:root{--blue:#0a5bd8;--navy:#0b1d3a;--yellow:#ffcc33;--green:#1eaa62;--bg:#f5f8fc;--text:#14213d;--muted:#5c677d;--card:#fff;--line:#dfe7f2}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--text);background:var(--bg);line-height:1.6}.site-header{min-height:72px;display:flex;align-items:center;gap:28px;padding:10px 5vw;background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}.brand{font-weight:850;font-size:1.5rem;text-decoration:none;color:var(--navy);display:flex;align-items:center;gap:8px}.blue,.blue-text{color:var(--blue)}.site-header nav{display:flex;gap:22px;margin:auto}.site-header nav a{color:var(--navy);text-decoration:none;font-weight:700}.search{width:250px;border:0;border-radius:999px;background:#eef2f7;padding:12px 16px;font-size:.95rem}.hero{min-height:430px;padding:56px 5vw;display:grid;grid-template-columns:1.1fr .9fr;gap:48px;align-items:center;background:linear-gradient(135deg,#123d78,#0763c8);color:#fff}.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-weight:850;font-size:.76rem;opacity:.9}.eyebrow.dark{color:var(--blue)}.hero h1{font-size:clamp(2.8rem,5.3vw,5.3rem);line-height:.97;margin:.2em 0}.hero h1 span{color:var(--yellow)}.hero p{font-size:1.15rem;max-width:760px}.hero-actions{display:flex;gap:14px;margin-top:28px}.button{padding:13px 22px;border-radius:12px;text-decoration:none;font-weight:850;border:0;cursor:pointer;font-size:1rem}.primary{background:var(--yellow);color:#15213b}.secondary{border:1px solid #fff;color:#fff}.hero-visual{height:310px;position:relative;min-width:320px}.orbit{position:absolute;width:74px;height:74px;border-radius:50%;display:grid;place-items:center;font-size:2.2rem;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.32);backdrop-filter:blur(4px)}.center{width:130px;height:130px;left:50%;top:50%;transform:translate(-50%,-50%);font-size:4.5rem}.o1{left:4%;top:8%}.o2{left:56%;top:0}.o3{left:10%;bottom:0}.o4{right:0;bottom:14%}.o5{right:2%;top:10%}.o6{left:46%;bottom:-4%}.bob{animation:bob 3.6s ease-in-out infinite}.delay1{animation-delay:.7s}.delay2{animation-delay:1.4s}@keyframes bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-11px)}}
.progress-dashboard{display:grid;grid-template-columns:1fr auto auto;gap:28px;align-items:center;padding:30px 5vw;background:#fff;border-bottom:1px solid var(--line)}.progress-dashboard h2{margin:0;font-size:1.65rem}.progress-dashboard p{margin:.25rem 0}.progress-ring{--p:0;width:92px;height:92px;border-radius:50%;display:grid;place-items:center;background:conic-gradient(var(--green) calc(var(--p)*1%),#e8eef6 0);position:relative;font-weight:900}.progress-ring:after{content:"";position:absolute;inset:10px;border-radius:50%;background:#fff}.progress-ring span{position:relative;z-index:1}.reset-button{border:1px solid var(--line);background:#fff;border-radius:10px;padding:9px 12px;color:var(--muted);cursor:pointer}.topics-section{padding:46px 5vw 36px}.section-heading{display:flex;justify-content:space-between;gap:24px;align-items:flex-end}.section-heading h2{font-size:2rem;margin:0}.section-heading p{margin-top:4px;color:var(--muted)}.filters{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}.filter{border:1px solid var(--line);background:#fff;border-radius:999px;padding:8px 12px;cursor:pointer}.filter.active{background:var(--navy);color:#fff}.topic-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;margin-top:24px}.topic-card{display:flex;flex-direction:column;background:var(--card);border:1px solid var(--line);border-radius:18px;padding:12px;text-decoration:none;color:var(--text);box-shadow:0 8px 24px rgba(29,51,84,.07);transition:.2s ease}.topic-card:hover{transform:translateY(-5px);box-shadow:0 15px 30px rgba(29,51,84,.13)}.topic-card h3{font-size:1.16rem;margin:9px 2px 4px}.topic-card p{font-size:.92rem;color:var(--muted);flex:1}.topic-card>span{font-size:.88rem;color:#24466e;font-weight:750}.card-art{height:145px;border-radius:13px;background:linear-gradient(135deg,#eef5ff,#dceaff);display:grid;place-items:center;position:relative;overflow:hidden}.topic-icon span{font-size:4.5rem;position:relative;z-index:2}.motion-ring{position:absolute;width:90px;height:90px;border:2px dashed rgba(10,91,216,.35);border-radius:50%;animation:spin 8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.card-topline{display:flex;justify-content:space-between;gap:10px;margin-top:12px;align-items:center}.card-topline small{color:var(--muted);font-weight:700}.progress-pill{font-size:.72rem;background:#eef2f7;color:#51627a;padding:4px 8px;border-radius:999px;white-space:nowrap}.progress-pill.done{background:#dcf6e8;color:#117642}.no-results{padding:20px}.why{display:grid;grid-template-columns:repeat(4,1fr);background:#fff;border-top:1px solid var(--line);margin-top:20px;padding:28px 5vw}.why div{padding:8px 24px;border-right:1px solid var(--line)}.why div:last-child{border-right:0}.why strong,.why span{display:block}.why span{font-size:.9rem;color:var(--muted);margin-top:4px}footer{text-align:center;padding:28px;color:var(--muted)}
.article-shell{max-width:940px;margin:0 auto;padding:44px 22px 80px}.article-back{text-decoration:none;color:var(--blue);font-weight:800}.article-hero{padding:34px 0 18px}.article-title-row{display:flex;gap:22px;align-items:center}.lesson-icon{font-size:4.2rem}.article-hero h1{font-size:clamp(2.5rem,6vw,4.6rem);line-height:1;margin:.12em 0}.article-hero .dek{font-size:1.2rem;color:var(--muted);max-width:760px}.meta{display:flex;gap:16px;flex-wrap:wrap;font-weight:700;color:#49607d}.animated-diagram{min-height:250px;background:linear-gradient(135deg,#0f3f7e,#0870d8);border-radius:22px;margin:28px 0;padding:28px;display:grid;grid-template-columns:170px 1fr;gap:18px;align-items:center;color:#fff;overflow:hidden}.diagram-icon{width:145px;height:145px;border-radius:50%;display:grid;place-items:center;font-size:5.4rem;background:rgba(255,255,255,.13);border:1px solid rgba(255,255,255,.3);animation:pulse 2.7s ease-in-out infinite}@keyframes pulse{50%{transform:scale(1.04)}}.diagram-track{height:58px;position:relative;border-top:3px solid rgba(255,255,255,.35);margin-top:45px}.diagram-track i{position:absolute;top:-10px;width:17px;height:17px;background:var(--yellow);border-radius:50%;animation:flow 4s linear infinite}.diagram-track i:nth-child(2){animation-delay:1s}.diagram-track i:nth-child(3){animation-delay:2s}.diagram-track i:nth-child(4){animation-delay:3s}@keyframes flow{0%{left:0;opacity:0}10%{opacity:1}90%{opacity:1}100%{left:calc(100% - 18px);opacity:0}}.diagram-copy{grid-column:2}.diagram-copy strong,.diagram-copy span{display:block}.diagram-copy strong{font-size:1.35rem}.diagram-copy span{opacity:.85}.lesson-section{padding:6px 0}.article-shell h2{font-size:1.75rem;margin-top:38px}.article-shell p,.article-shell li{font-size:1.08rem}.callout{background:#eef6ff;border-left:5px solid var(--blue);padding:18px 20px;border-radius:12px;margin:24px 0}.challenge{background:#fff8d8;border:1px solid #f5d55d;padding:20px;border-radius:14px;margin:30px 0}.quiz-card{background:#fff;border:1px solid var(--line);border-radius:22px;padding:28px;margin-top:46px;box-shadow:0 10px 28px rgba(29,51,84,.07)}.quiz-card h2{margin-top:0}.quiz-question{border:0;border-top:1px solid var(--line);padding:24px 0 12px}.quiz-question legend{font-weight:850;font-size:1.05rem;padding-top:18px}.answer{display:flex;gap:10px;align-items:flex-start;background:#f7f9fc;border:1px solid transparent;border-radius:10px;padding:10px 12px;margin:8px 0;cursor:pointer}.answer:hover{border-color:#bfd5f5}.answer input{margin-top:5px}.answer.correct{background:#e6f8ee;border-color:#83d7aa}.answer.wrong{background:#fff0f0;border-color:#efabab}.answer-feedback{font-size:.9rem!important;font-weight:750;margin:.4rem 0}.quiz-submit{margin-top:10px}.quiz-result{margin-top:20px;padding:18px;border-radius:12px;background:#eef6ff;font-size:1.1rem;font-weight:800}.complete-card{display:flex;justify-content:space-between;gap:24px;align-items:center;background:#102447;color:#fff;border-radius:18px;padding:24px;margin-top:28px}.complete-card h2{margin:0}.complete-card p{margin:.3rem 0 0;color:#dbe6f6}.complete-button{background:#fff;color:#102447;white-space:nowrap}.complete-button.completed{background:#dcf6e8;color:#117642}.next-card{display:block;margin-top:30px;background:var(--navy);color:#fff;padding:22px;border-radius:16px;text-decoration:none;font-weight:800}.lesson-progress{width:170px}.lesson-progress>span{font-size:.78rem;font-weight:800}.lesson-progress>div{height:7px;border-radius:999px;background:#e8eef6;overflow:hidden}.lesson-progress i{display:block;height:100%;width:0;background:var(--blue);transition:width .2s}.reveal{opacity:0;transform:translateY(18px);transition:opacity .55s ease,transform .55s ease}.reveal.visible{opacity:1;transform:none}
@media(max-width:1100px){.topic-grid{grid-template-columns:repeat(3,1fr)}.site-header nav{display:none}.search{margin-left:auto}.hero{grid-template-columns:1fr}.hero-visual{display:none}}@media(max-width:760px){.site-header{padding:10px 18px}.search{width:44px}.search::placeholder{color:transparent}.lesson-progress{margin-left:auto;width:100px}.progress-dashboard{grid-template-columns:1fr auto}.reset-button{grid-column:1/-1;width:max-content}.section-heading{align-items:flex-start;flex-direction:column}.filters{justify-content:flex-start}.topic-grid{grid-template-columns:1fr}.why{grid-template-columns:1fr}.why div{border-right:0;border-bottom:1px solid var(--line)}.hero{padding:42px 22px}.topics-section{padding:36px 18px}.hero-actions{flex-direction:column;align-items:flex-start}.animated-diagram{grid-template-columns:1fr;text-align:center}.diagram-icon{margin:auto}.diagram-track{display:none}.diagram-copy{grid-column:1}.article-title-row{align-items:flex-start}.lesson-icon{font-size:3rem}.complete-card{flex-direction:column;align-items:flex-start}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}.bob,.motion-ring,.diagram-icon,.diagram-track i{animation:none!important}.reveal{opacity:1;transform:none;transition:none}}


/* Interactive engineering labs */
.interactive-lab{background:#fff;border:1px solid var(--line);border-radius:22px;padding:26px;margin:32px 0;box-shadow:0 12px 32px rgba(29,51,84,.08)}
.lab-heading{display:flex;justify-content:space-between;gap:22px;align-items:flex-start}.lab-heading h2{margin:.15rem 0 .35rem}.lab-heading p{margin:.25rem 0;color:var(--muted)}.lab-badge{background:#fff1ac;color:#6a5300;font-weight:900;border-radius:999px;padding:7px 11px;white-space:nowrap}
.sim-stage{margin:24px 0;min-height:160px;border-radius:18px;background:linear-gradient(180deg,#eff6ff,#f9fbfe);border:1px solid #dce8f8;padding:22px;display:flex;align-items:center;justify-content:space-between;gap:12px;overflow:hidden}.sim-node{min-width:120px;min-height:112px;background:#fff;border:1px solid #d7e2ef;border-radius:16px;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:12px;text-align:center;box-shadow:0 5px 14px rgba(29,51,84,.06);position:relative;z-index:2}.sim-node span{font-size:2.7rem}.sim-node b{font-size:.92rem}.sim-node small{color:var(--muted)}
.sim-arrow{height:8px;min-width:58px;flex:1;border-radius:999px;background:#d8e3ef;position:relative;overflow:hidden}.sim-arrow.long{flex:1.4}.sim-arrow i{position:absolute;width:24px;height:100%;border-radius:999px;background:var(--yellow);left:-28px}.interactive-lab.running .sim-arrow i{animation:labFlow 1.2s linear infinite}@keyframes labFlow{to{left:105%}}
.lab-controls{display:flex;gap:14px;align-items:center;flex-wrap:wrap}.lab-controls label{font-weight:800;background:#f7f9fc;border:1px solid var(--line);border-radius:12px;padding:10px 12px}.lab-controls select,.lab-controls input[type=range]{margin-left:8px}.sim-explain{background:#eef6ff;border-radius:12px;padding:13px 15px;margin:16px 0 0!important;font-size:.98rem!important}.sim-action{min-width:145px}
.car-sim .wheels.spin span{animation:wheelSpin .65s linear infinite}@keyframes wheelSpin{to{transform:rotate(360deg)}}.car-sim .engine.fire span{animation:engineShake .16s linear infinite alternate}@keyframes engineShake{to{transform:translateX(2px)}}
.wifi-space{flex:1;height:110px;position:relative;min-width:75px}.wifi-space em{position:absolute;inset:38px 0 auto;text-align:center;font-style:normal;font-size:1.4rem;color:#71a7e8;letter-spacing:5px}.wifi-space .packet{position:absolute;z-index:2;top:38px;left:-10px;background:var(--yellow);color:#13233d;border-radius:8px;padding:4px 6px;font-style:normal;font-weight:900;opacity:0}.wifi-sim.sending .wifi-space .packet{animation:packetMove var(--packet-speed,1.2s) linear forwards}@keyframes packetMove{0%{left:0;opacity:0}12%{opacity:1}88%{opacity:1}100%{left:calc(100% - 36px);opacity:0}}
.grid-sim.powered .sim-node{box-shadow:0 0 0 3px rgba(255,209,61,.28),0 5px 14px rgba(29,51,84,.06)}.grid-sim.powered .demand-node span{animation:housePulse .8s ease-in-out 2}@keyframes housePulse{50%{transform:scale(1.14)}}
.fridge-sim .cold.cooling{background:#e6f5ff}.fridge-sim .hot.heating{background:#fff0e5}.fridge-sim .compressor.active span{animation:compressorSpin .65s linear infinite}@keyframes compressorSpin{to{transform:rotate(360deg)}}
.rocket-stage{height:240px;margin:24px 0;border-radius:18px;background:linear-gradient(#0e244b,#07152f);position:relative;overflow:hidden}.rocket-body{position:absolute;left:46%;top:83px;font-size:4.8rem;z-index:2;transition:transform .9s cubic-bezier(.2,.8,.2,1)}.rocket-stage.launch .rocket-body{transform:translateY(var(--rocket-rise,-55px))}.exhaust{position:absolute;left:calc(46% + 31px);top:153px;width:22px;height:70px}.exhaust i{position:absolute;width:8px;height:18px;border-radius:50%;background:#ffd44c;left:7px;opacity:.25}.rocket-stage.launch .exhaust i{animation:exhaustDrop .55s linear infinite}.exhaust i:nth-child(2){animation-delay:.12s!important}.exhaust i:nth-child(3){animation-delay:.24s!important}.exhaust i:nth-child(4){animation-delay:.36s!important}@keyframes exhaustDrop{0%{transform:translateY(0) scale(1);opacity:1}100%{transform:translateY(55px) scale(.35);opacity:0}}.force-label{position:absolute;color:#d8e7ff;font-weight:800;font-size:.9rem;top:22px}.force-label.backward{left:20px}.force-label.forward{right:20px}
.interactive-lab.interacted .lab-badge{background:#dcf6e8;color:#117642}.interactive-lab.interacted .lab-badge::before{content:'✓ '}
@media(max-width:760px){.lab-heading{flex-direction:column}.sim-stage{overflow-x:auto;justify-content:flex-start}.sim-node{min-width:105px}.sim-arrow{min-width:52px}.wifi-space{min-width:75px}.rocket-stage{height:210px}.lab-controls{align-items:stretch;flex-direction:column}.lab-controls label,.sim-action{width:100%}.lab-controls select{max-width:100%}}
@media(prefers-reduced-motion:reduce){.interactive-lab.running .sim-arrow i,.car-sim .wheels.spin span,.car-sim .engine.fire span,.wifi-sim.sending .wifi-space .packet,.fridge-sim .compressor.active span,.rocket-stage.launch .exhaust i,.grid-sim.powered .demand-node span{animation:none!important}.rocket-body{transition:none!important}}

.flagship-card{outline:2px solid rgba(20,108,224,.14)}.flagship-label{display:inline-block;font-size:.68rem;font-weight:950;letter-spacing:.08em;color:#0b67c9;background:#eaf4ff;padding:5px 8px;border-radius:999px;margin-bottom:8px}.premium-lab{background:#fff;border:1px solid var(--line);border-radius:24px;padding:28px;margin:34px 0;box-shadow:0 14px 40px rgba(29,51,84,.09)}.premium-head{display:flex;justify-content:space-between;gap:20px;align-items:flex-start}.premium-head h2{margin:.15rem 0}.mission-pill{background:#102447;color:#fff;font-size:.72rem;font-weight:950;padding:8px 11px;border-radius:999px;white-space:nowrap}.premium-controls{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:18px 0}.premium-controls label{display:grid;grid-template-columns:auto 1fr auto;gap:10px;align-items:center;background:#f7f9fc;border:1px solid var(--line);border-radius:12px;padding:12px;font-weight:800}.flight-sky{height:260px;border-radius:18px;background:linear-gradient(#bfe4ff 0 70%,#dceec7 70%);position:relative;overflow:hidden;margin:22px 0}.plane{position:absolute;left:43%;top:100px;font-size:5rem;transition:transform .35s}.horizon{position:absolute;left:0;right:0;top:70%;border-top:3px solid rgba(255,255,255,.8)}.force{position:absolute;font-weight:950;color:#102447}.force.lift{left:48%;top:20px}.force.weight{left:48%;bottom:18px}.instrument-row{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.instrument-row div{background:#102447;color:#fff;border-radius:14px;padding:14px;text-align:center}.instrument-row span,.instrument-row strong{display:block}.solar-scene{height:260px;border-radius:18px;background:linear-gradient(#cceaff 0 68%,#b8d899 68%);position:relative;overflow:hidden;margin:22px 0}.sun{position:absolute;left:65%;top:25px;font-size:4rem}.cloud{position:absolute;left:50%;top:42px;font-size:4rem;opacity:.1}.panel-bank{position:absolute;left:20%;bottom:35px;font-size:2.4rem;color:#183f79}.solar-house{position:absolute;right:12%;bottom:25px;font-size:4.5rem}.power-meter{display:flex;align-items:center;gap:14px}.power-meter>div{height:18px;flex:1;background:#e7edf4;border-radius:999px;overflow:hidden}.power-meter i{display:block;height:100%;width:65%;background:var(--blue)}.ipad-lab{display:grid;grid-template-columns:240px 1fr;gap:28px;align-items:center;margin:22px 0}.tablet-screen{height:320px;border:10px solid #20242c;border-radius:28px;background:linear-gradient(135deg,#d8edff,#f6f1ff);position:relative;font:inherit;font-weight:900;color:#174e8e}.tablet-screen i{position:absolute;width:30px;height:30px;border:3px solid var(--blue);border-radius:50%;left:50%;top:50%;transform:translate(-50%,-50%) scale(.2);opacity:0}.tablet-screen.tapped i{animation:tapRipple .65s ease-out}@keyframes tapRipple{0%{opacity:1;transform:translate(-50%,-50%) scale(.2)}100%{opacity:0;transform:translate(-50%,-50%) scale(3.5)}}.signal-path{display:grid;gap:10px}.chip-step{border:1px solid var(--line);border-radius:14px;padding:13px;display:grid;grid-template-columns:34px 1fr;gap:2px 10px;opacity:.4;transition:.25s}.chip-step b{grid-row:1/3}.chip-step.active{opacity:1;background:#eef6ff;transform:translateX(6px)}.latency{display:flex;justify-content:space-between;padding:13px 15px;background:#102447;color:#fff;border-radius:12px}.engineer-card{display:grid;grid-template-columns:80px 1fr;gap:20px;background:linear-gradient(135deg,#102447,#173e75);color:#fff;border-radius:22px;padding:26px;margin:38px 0}.engineer-card p{color:#dce8f8}.engineer-icon{font-size:3.5rem}.premium-success{color:#147d45!important}.premium-warn{color:#ffb09b!important}@media(max-width:760px){.premium-head{flex-direction:column}.premium-controls,.instrument-row,.ipad-lab{grid-template-columns:1fr}.tablet-screen{height:240px}.engineer-card{grid-template-columns:1fr}}

/* v4.1: simplified, highly visual car story simulation */
.car-story-lab{background:#fff;border:1px solid var(--line);border-radius:26px;padding:28px;margin:34px 0;box-shadow:0 15px 42px rgba(25,52,88,.1)}
.car-story-head{display:flex;justify-content:space-between;align-items:flex-start;gap:20px}.car-story-head h2{margin:.15rem 0 .35rem}.car-story-head>div>p:last-child{color:var(--muted);max-width:760px}
.car-story-layout{display:grid;grid-template-columns:190px minmax(0,1fr);gap:20px;margin-top:24px}.pedal-panel{background:#f6f9fd;border:1px solid var(--line);border-radius:18px;padding:18px;text-align:center}.step-kicker{display:flex;align-items:center;gap:8px;font-weight:900;text-align:left;margin:0 0 16px}.step-kicker span{display:grid;place-items:center;width:28px;height:28px;border-radius:50%;background:var(--blue);color:#fff}
.gas-pedal{width:118px;height:178px;margin:0 auto 14px;border:0;background:transparent;cursor:pointer;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;color:var(--ink);touch-action:none}.pedal-face{display:grid;place-items:center;width:72px;height:118px;border-radius:18px;background:linear-gradient(145deg,#3d4857,#151b23);color:#98a6b8;font-size:3.5rem;box-shadow:inset 6px 6px 12px rgba(255,255,255,.08),0 8px 0 #0d1117;transition:transform .12s,box-shadow .12s}.gas-pedal:active .pedal-face,.gas-pedal.pressed .pedal-face{transform:perspective(200px) rotateX(15deg) translateY(7px);box-shadow:inset 6px 6px 12px rgba(255,255,255,.08),0 2px 0 #0d1117}.gas-pedal strong{font-size:.92rem}.gas-pedal small{color:var(--muted)}.throttle-readout{display:flex;justify-content:space-between;align-items:center;background:#102447;color:#fff;padding:9px 11px;border-radius:10px;font-size:.82rem}.throttle-readout strong{font-size:1.05rem}.pedal-help{font-size:.76rem!important;color:var(--muted);line-height:1.4;margin:14px 0 0}
.engine-window{min-height:420px;position:relative;overflow:hidden;border-radius:20px;background:linear-gradient(180deg,#eaf4ff 0 44%,#f9fbfe 44%);border:1px solid #cbd9e8}.story-label{position:absolute;font-size:.75rem;font-weight:900;padding:5px 8px;border-radius:999px;background:#fff;border:1px solid #cedbea;z-index:4}.fuel-label{left:5%;top:11%;color:#a66b00}.air-label{left:5%;top:27%;color:#0873ba}.fuel-line,.air-line{position:absolute;left:12%;width:27%;height:8px;border-radius:999px;z-index:2}.fuel-line{top:18%;background:#ffd464}.air-line{top:34%;background:#9bdcff}.fuel-line:after,.air-line:after{content:'›';position:absolute;right:-5px;top:-16px;font-size:2rem;font-weight:900}.fuel-line:after{color:#d49a00}.air-line:after{color:#1992d4}.fuel-drop,.air-dot{position:absolute;width:10px;height:10px;border-radius:50%;left:0;top:-1px;opacity:.2}.fuel-drop{background:#e7a500}.air-dot{background:#168fce}.engine-window.running .fuel-drop,.engine-window.running .air-dot{animation:storyFlow 1s linear infinite}.engine-window.running .d2,.engine-window.running .a2{animation-delay:.3s}.engine-window.running .d3,.engine-window.running .a3{animation-delay:.6s}@keyframes storyFlow{0%{left:0;opacity:.1}15%{opacity:1}100%{left:94%;opacity:.2}}
.injector{position:absolute;left:37%;top:12%;width:74px;height:70px;border-radius:12px;background:#37465a;color:#fff;display:grid;place-items:center;font-size:.63rem;text-align:center;z-index:5}.injector i{position:absolute;width:8px;height:37px;background:#d9a417;bottom:-28px;left:34px}.spark-plug{position:absolute;left:49%;top:8%;text-align:center;font-size:.68rem;font-weight:900;z-index:6}.spark-plug i{display:block;font-style:normal;font-size:1.5rem;opacity:.3}.engine-window.ignite .spark-plug i{animation:spark .35s ease 2}@keyframes spark{50%{opacity:1;transform:scale(1.45)}}
.cylinder{position:absolute;left:38%;top:28%;width:145px;height:190px;border:12px solid #64758a;border-top:16px solid #3d4d61;border-radius:18px 18px 8px 8px;background:linear-gradient(#253447 0 4%,#e7edf4 4%);overflow:hidden;z-index:3}.combustion{position:absolute;left:15px;right:15px;top:14px;height:62px;display:grid;place-items:center;border-radius:50%;opacity:.1;transform:scale(.35);background:radial-gradient(circle,#fff0a9 0,#ff9d24 42%,#ee5627 75%,transparent 76%)}.combustion span{font-size:2.2rem}.engine-window.ignite .combustion{animation:boom .55s ease-out}@keyframes boom{0%{opacity:.2;transform:scale(.3)}45%{opacity:1;transform:scale(1.25)}100%{opacity:.45;transform:scale(.8)}}.piston{position:absolute;left:10px;right:10px;top:72px;height:62px;border-radius:8px;background:linear-gradient(#bac6d4,#76869a);border:2px solid #56677b;display:grid;place-items:center;color:#26364a;font-size:.65rem;font-weight:950;transition:transform .22s}.engine-window.running .piston{animation:pistonPump .7s ease-in-out infinite}.engine-window.ignite .piston{animation:pistonKick .48s ease-out}@keyframes pistonPump{0%,100%{transform:translateY(-13px)}50%{transform:translateY(27px)}}@keyframes pistonKick{0%{transform:translateY(-18px)}100%{transform:translateY(35px)}}.rod{position:absolute;width:10px;height:80px;background:#66778b;left:66px;top:128px;transform-origin:top center}.crank{position:absolute;left:39%;top:78%;width:130px;height:18px;background:#4b5b6d;border-radius:999px;z-index:5;transform-origin:center}.crank i{position:absolute;width:42px;height:42px;border:10px solid #64778c;border-radius:50%;left:45px;top:-12px}.crank span{position:absolute;top:30px;width:130px;text-align:center;font-size:.7rem;font-weight:900}.engine-window.running .crank,.engine-window.ignite .crank{animation:crankSpin .7s linear infinite}@keyframes crankSpin{to{transform:rotate(360deg)}}
.power-shaft{position:absolute;left:55%;top:69%;width:24%;height:9px;background:#6c7f94;border-radius:10px}.power-shaft i{position:absolute;left:0;top:-4px;width:18px;height:18px;border-radius:50%;background:#ffc43d;opacity:0}.engine-window.running .power-shaft i{animation:powerPulse .9s linear infinite}@keyframes powerPulse{0%{left:0;opacity:.2}20%{opacity:1}100%{left:94%;opacity:.2}}.mini-gear{position:absolute;left:68%;top:58%;text-align:center;font-size:2.4rem}.mini-gear small{display:block;font-size:.7rem;font-weight:900}.engine-window.running .mini-gear span{display:block;animation:crankSpin 1.1s linear infinite}.story-wheel{position:absolute;right:6%;top:48%;width:115px;height:115px;border:18px solid #27313e;border-radius:50%;background:#d6e0ea;display:grid;place-items:center}.story-wheel i{width:18px;height:18px;border-radius:50%;background:#26384d;box-shadow:0 -36px 0 -4px #738499,0 36px 0 -4px #738499,36px 0 0 -4px #738499,-36px 0 0 -4px #738499}.story-wheel span{position:absolute;top:118px;font-size:.7rem;font-weight:900}.engine-window.running .story-wheel{animation:wheelTurn .65s linear infinite}@keyframes wheelTurn{to{transform:rotate(360deg)}}.flow-caption{position:absolute;left:4%;right:4%;bottom:18px;background:rgba(16,36,71,.94);color:#fff;padding:12px 15px;border-radius:12px;font-size:.88rem;z-index:10}.flow-caption strong{color:#ffd361}
.car-story-steps{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin-top:14px}.car-story-steps button{border:1px solid var(--line);background:#fff;border-radius:12px;padding:10px 8px;display:grid;grid-template-columns:28px 1fr;gap:1px 8px;text-align:left;cursor:pointer;color:var(--ink)}.car-story-steps b{grid-row:1/3;display:grid;place-items:center;width:26px;height:26px;border-radius:50%;background:#eaf3ff;color:var(--blue)}.car-story-steps span{font-weight:900;font-size:.78rem}.car-story-steps small{color:var(--muted);font-size:.67rem}.car-story-steps button.active{background:#eaf4ff;border-color:#8dbff6;transform:translateY(-2px)}.car-story-insight{display:flex;gap:10px;align-items:flex-start;background:#fff7d8;border-radius:14px;padding:13px 15px;margin-top:14px}.car-story-insight span{font-size:1.35rem}.car-story-insight p{margin:0;font-size:.88rem;line-height:1.45}
@media(max-width:820px){.car-story-layout{grid-template-columns:1fr}.pedal-panel{display:grid;grid-template-columns:auto 1fr;align-items:center;gap:10px}.pedal-panel .step-kicker,.pedal-panel .pedal-help{grid-column:1/-1}.gas-pedal{height:150px}.pedal-face{height:95px}.car-story-steps{grid-template-columns:1fr 1fr}.engine-window{min-height:390px}.story-wheel{right:3%;width:88px;height:88px;border-width:14px}.story-wheel span{top:94px}.cylinder{left:34%}.crank{left:35%}.power-shaft{left:53%}}
@media(max-width:520px){.car-story-lab{padding:18px}.car-story-head{flex-direction:column}.engine-window{min-height:455px}.fuel-line,.air-line{width:23%}.cylinder{left:30%;top:27%;width:125px}.injector{left:29%}.spark-plug{left:48%}.crank{left:28%;top:72%}.power-shaft{left:50%;top:66%;width:22%}.mini-gear{left:62%;top:56%}.story-wheel{right:3%;top:48%;width:76px;height:76px;border-width:12px}.story-wheel i{transform:scale(.7)}.story-wheel span{top:82px}.flow-caption{bottom:12px}.car-story-steps{grid-template-columns:1fr}.mission-pill{white-space:normal}}
@media(prefers-reduced-motion:reduce){.engine-window.running *,.engine-window.ignite *{animation:none!important;transition:none!important}}

/* v5 simplified visual flagship labs */
.chain-lab{background:#fff;border:1px solid var(--line);border-radius:24px;padding:28px;margin:34px 0;box-shadow:0 14px 38px rgba(29,51,84,.09)}.chain-head{text-align:center;max-width:680px;margin:auto}.chain-head h2{margin:.15rem 0 .4rem}.air-stage,.solar-chain-stage,.rocket-stage{height:300px;border-radius:20px;position:relative;overflow:hidden;margin:22px 0}.air-stage{background:linear-gradient(#c9eaff 0 72%,#cde4b4 72%)}.airplane-big{position:absolute;left:42%;top:105px;font-size:6rem;transition:.25s}.wind-lines{position:absolute;left:4%;right:48%;top:95px}.wind-lines i{display:block;border-top:3px solid rgba(255,255,255,.9);margin:18px 0;animation:wind 1.4s linear infinite}.wind-lines i:nth-child(2){width:80%}.wind-lines i:nth-child(3){width:65%}@keyframes wind{from{transform:translateX(-30px);opacity:.2}to{transform:translateX(80px);opacity:1}}.lift-arrow,.drag-arrow{position:absolute;font-weight:950;color:#153d70;font-size:2rem;transition:.25s}.lift-arrow{left:55%;top:22px}.drag-arrow{left:28%;top:135px}.lift-arrow span,.drag-arrow span{font-size:.75rem;display:block}.ground-line{position:absolute;bottom:28%;left:0;right:0;border-top:3px solid rgba(255,255,255,.8)}.two-knobs{display:grid;grid-template-columns:1fr 1fr;gap:14px}.two-knobs label{background:#f6f8fb;border:1px solid var(--line);border-radius:14px;padding:14px;display:grid;grid-template-columns:auto 1fr auto;gap:12px;align-items:center;font-weight:850}.chain-status{background:#102447;color:#fff;padding:14px 18px;border-radius:14px;margin:16px 0;text-align:center}.flow-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin-top:15px}.flow-strip button{border:1px solid var(--line);background:#f7f9fc;border-radius:12px;padding:11px 8px;font-weight:850;color:#17375f;cursor:pointer}.flow-strip button:hover,.flow-strip button.active{background:#e9f4ff;border-color:#7db7ee}.flow-note{text-align:center;color:var(--muted);min-height:28px}.solar-chain-stage{background:linear-gradient(#cceaff 0 68%,#c3dfa6 68%)}.movable-sun{position:absolute;top:25px;left:65%;font-size:4.5rem;transition:.3s}.movable-cloud{position:absolute;top:45px;left:48%;font-size:4rem;opacity:.1;transition:.3s}.photon-stream{position:absolute;left:35%;top:100px;transform:rotate(28deg)}.photon-stream i{display:inline-block;width:12px;height:12px;border-radius:50%;background:#ffd73f;margin:9px;animation:photon 1s infinite}@keyframes photon{50%{transform:translate(35px,35px);opacity:.35}}.panel-visual{position:absolute;left:18%;bottom:42px;font-size:3rem;color:#173f7a;transform:skew(-12deg)}.wire-flow{position:absolute;left:39%;bottom:58px;color:#0a79db;font-size:1.6rem;letter-spacing:8px}.inverter-box{position:absolute;left:58%;bottom:42px;background:#fff;border:3px solid #7891aa;border-radius:8px;padding:13px 7px;font-size:.7rem;font-weight:950}.house-visual{position:absolute;right:8%;bottom:28px;font-size:5rem;filter:grayscale(.6);transition:.3s}.ipad-chain{display:grid;grid-template-columns:230px 1fr;gap:28px;align-items:center;margin:25px 0}.ipad-device{height:300px;border:11px solid #20242c;border-radius:28px;background:linear-gradient(135deg,#d7edff,#f2eaff);position:relative;font:inherit;font-weight:950;color:#145a9d;cursor:pointer}.finger-dot{position:absolute;left:50%;top:50%;width:28px;height:28px;border:3px solid #0b78df;border-radius:50%;opacity:0;transform:translate(-50%,-50%) scale(.2)}.ipad-device.tapped .finger-dot{animation:tap5 .6s ease-out}@keyframes tap5{0%{opacity:1;transform:translate(-50%,-50%) scale(.2)}100%{opacity:0;transform:translate(-50%,-50%) scale(4)}}.ipad-guts{display:flex;align-items:center;gap:7px;flex-wrap:wrap}.guts-step{flex:1;min-width:105px;border:1px solid var(--line);border-radius:14px;padding:15px;text-align:center;opacity:.35;transition:.2s}.guts-step b,.guts-step span{display:block}.guts-step b{font-size:2rem}.guts-step.active{opacity:1;background:#eaf5ff;transform:translateY(-5px)}.path-dot{font-weight:950;color:#7790aa}.rocket-stage{background:linear-gradient(#07152f,#173d72);height:360px}.tank{position:absolute;top:35px;width:80px;height:120px;border-radius:20px;padding-top:45px;text-align:center;font-weight:950;color:#fff}.fuel-tank{left:10%;background:#d1842e}.oxy-tank{left:27%;background:#2d87cf}.fuel-pipe,.oxy-pipe{position:absolute;top:145px;height:5px;width:130px;opacity:.3}.fuel-pipe{left:16%;background:#ffad3d;transform:rotate(18deg)}.oxy-pipe{left:31%;background:#58c9ff;transform:rotate(8deg)}.rocket-body{position:absolute;left:58%;top:65px;font-size:8rem;transition:.25s}.combustion-glow{position:absolute;left:66%;top:205px;width:45px;height:45px;border-radius:50%;background:#ffbf36;opacity:0;box-shadow:0 0 30px #ff6b22}.exhaust-plume{position:absolute;left:65%;top:225px;width:55px;height:110px;background:linear-gradient(#fff3a6,#ff7b22,transparent);clip-path:polygon(25% 0,75% 0,100% 100%,50% 78%,0 100%);opacity:0}.rocket-label{position:absolute;color:#fff;font-weight:950;opacity:.45}.rocket-label.upward{right:14%;top:55px}.rocket-label.downward{right:12%;bottom:30px}.ignite-button{display:block;margin:0 auto;background:#f5b72e;border:0;border-radius:16px;padding:16px 26px;font:inherit;font-weight:950;cursor:pointer;box-shadow:0 5px 0 #bd8111}.ignite-button:active,.ignite-button.firing{transform:translateY(4px);box-shadow:0 1px 0 #bd8111}.rocket-stage.firing .fuel-pipe,.rocket-stage.firing .oxy-pipe,.rocket-stage.firing .combustion-glow,.rocket-stage.firing .exhaust-plume{opacity:1}.rocket-stage.firing .rocket-body{transform:translateY(-25px)}@media(max-width:760px){.two-knobs,.flow-strip{grid-template-columns:1fr}.two-knobs label{grid-template-columns:1fr}.ipad-chain{grid-template-columns:1fr}.ipad-device{height:230px}.ipad-guts{display:grid;grid-template-columns:1fr}.path-dot{display:none}.air-stage,.solar-chain-stage{height:240px}.rocket-stage{height:320px}}

/* v5.1 close-up solar cell */
.cell-lab{background:#fff;border:1px solid var(--line);border-radius:24px;padding:28px;margin:34px 0;box-shadow:0 14px 38px rgba(29,51,84,.09)}.cell-head{text-align:center;max-width:760px;margin:auto}.cell-head h2{margin:.15rem 0 .45rem}.cell-controls{display:flex;gap:14px;justify-content:space-between;align-items:center;margin:22px 0;flex-wrap:wrap}.cell-controls>label{flex:1;min-width:260px;display:grid;grid-template-columns:auto 1fr auto;gap:12px;align-items:center;background:#fff8df;border:1px solid #f1d57a;border-radius:14px;padding:13px;font-weight:900}.weather-buttons{display:flex;gap:7px}.weather-buttons button{border:1px solid var(--line);background:#f7f9fc;border-radius:12px;padding:11px;font-weight:800;cursor:pointer}.cell-world{height:440px;position:relative;overflow:hidden;border-radius:20px;background:linear-gradient(#cceaff 0 38%,#edf4fa 38%);border:1px solid #d6e2ed}.cell-sun{position:absolute;left:8%;top:25px;font-size:5rem}.photon-zone{position:absolute;left:19%;top:82px;width:34%;height:135px;transform:rotate(20deg)}.photon-zone i{position:absolute;width:14px;height:14px;border-radius:50%;background:#ffd42a;box-shadow:0 0 10px #ffd42a;animation:cellPhoton 1.35s linear infinite}.photon-zone i:nth-child(1){left:5%;top:10%;animation-delay:0s}.photon-zone i:nth-child(2){left:20%;top:35%;animation-delay:.25s}.photon-zone i:nth-child(3){left:38%;top:5%;animation-delay:.5s}.photon-zone i:nth-child(4){left:52%;top:48%;animation-delay:.75s}.photon-zone i:nth-child(5){left:70%;top:20%;animation-delay:1s}.photon-zone i:nth-child(6){left:85%;top:60%;animation-delay:1.2s}@keyframes cellPhoton{from{transform:translate(-60px,-45px);opacity:.1}to{transform:translate(65px,75px);opacity:1}}.cell-stack{position:absolute;left:18%;right:28%;top:205px;height:190px;border:5px solid #52687c;border-radius:8px;overflow:hidden;box-shadow:0 8px 20px rgba(0,0,0,.16)}.silicon{height:46%;position:relative;padding:13px 16px;color:#fff;font-weight:900}.silicon small{display:block;font-weight:500;opacity:.85}.n-layer{background:linear-gradient(135deg,#1266a8,#2d92d0)}.p-layer{background:linear-gradient(135deg,#9e3f59,#d05d70)}.junction{height:8%;background:#dfe8ee;text-align:center;font-size:.72rem;font-weight:950;color:#324b61;padding-top:2px}.electron,.hole{position:absolute;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;font-weight:950}.electron{background:#086ed0;border:2px solid #fff}.hole{background:#ef4e5d;border:2px solid #fff}.e1{left:42%;top:28%}.e2{left:62%;top:52%}.e3{left:80%;top:22%}.h1{left:48%;top:20%}.h2{left:67%;top:48%}.h3{left:84%;top:18%}.wire-loop{position:absolute;right:5%;top:190px;width:19%;height:205px;border:6px solid #e7aa16;border-left:0;border-radius:0 24px 24px 0}.bulb{position:absolute;right:-25px;top:65px;font-size:4rem;filter:grayscale(1);transition:.3s}.moving-charge{position:absolute;color:#076dcc;background:#fff;border:2px solid #0b78df;border-radius:50%;width:26px;height:26px;text-align:center;font-weight:950;animation:chargeMove 2s linear infinite}.c1{top:-15px;left:10%}.c2{right:-15px;top:30%}.c3{bottom:-15px;left:30%}@keyframes chargeMove{50%{transform:translateY(35px)}}.cell-meter{display:grid;grid-template-columns:220px 1fr;gap:18px;align-items:center;margin:18px 0}.cell-meter span,.cell-meter strong{display:block}.cell-meter strong{font-size:1.5rem;color:#0b67c9}.meter-track{height:22px;background:#e5ebf1;border-radius:999px;overflow:hidden}.meter-track i{display:block;height:100%;width:70%;background:#39b96b;transition:.25s}.cell-steps{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}.cell-steps button{display:flex;align-items:center;gap:8px;border:1px solid var(--line);background:#f7f9fc;border-radius:12px;padding:12px;text-align:left;font-weight:850;cursor:pointer}.cell-steps b{width:27px;height:27px;border-radius:50%;background:#dcecff;color:#075eaf;display:grid;place-items:center}.cell-steps button.active{background:#e9f4ff;border-color:#74b2e9}.cell-explain{background:#102447;color:#eaf3ff;border-radius:14px;padding:16px;margin-top:12px;min-height:62px}.cell-world[data-power="high"] .bulb{filter:none}.cell-world[data-power="high"] .moving-charge{animation-duration:.75s}.cell-world[data-power="low"] .moving-charge{animation-duration:3.5s;opacity:.55}@media(max-width:760px){.cell-world{height:520px}.cell-stack{left:7%;right:7%;top:220px}.wire-loop{left:32%;right:auto;top:415px;width:45%;height:70px;border-left:6px solid #e7aa16;border-top:0;border-radius:0 0 20px 20px}.bulb{right:-35px;top:5px}.cell-meter{grid-template-columns:1fr}.cell-steps{grid-template-columns:1fr}.weather-buttons{width:100%;display:grid;grid-template-columns:1fr}.photon-zone{left:24%;width:50%}}

/* v5.2 car cutaway simulation */
.car-cutaway{position:relative;background:#071b31;color:#fff;border-radius:26px;padding:26px;margin:34px 0;box-shadow:0 18px 48px rgba(8,28,52,.24);overflow:hidden}.cutaway-head{display:flex;justify-content:space-between;gap:20px;align-items:flex-start}.cutaway-head h2{color:#fff;margin:.15rem 0 .4rem}.cutaway-head p{color:#c8d8e8;max-width:760px}.cutaway-reset{border:1px solid #365572;background:#102c49;color:#dcecff;border-radius:10px;padding:9px 12px;font-weight:800;cursor:pointer}.cutaway-grid{display:grid;grid-template-columns:190px minmax(430px,1fr) 250px;gap:16px;align-items:stretch;margin-top:20px}.pedal-console,.engine-steps{background:rgba(4,20,37,.72);border:1px solid #31516e;border-radius:18px;padding:16px}.console-step{display:flex;gap:8px;align-items:center;font-weight:900}.console-step b,.engine-step b{display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:#1684ed;color:#fff;flex:none}.real-pedal{display:block;width:100px;height:178px;margin:18px auto;background:transparent;border:0;cursor:pointer;touch-action:none}.pedal-grooves{display:grid;place-items:center;width:72px;height:138px;margin:auto;background:linear-gradient(145deg,#4a5662,#171e26);border:3px solid #8e99a4;border-radius:14px;color:#9aa6b0;font-size:3rem;box-shadow:0 12px 0 #080d12;transform-origin:bottom;transition:.12s}.real-pedal.pressed .pedal-grooves{transform:perspective(220px) rotateX(18deg) translateY(10px);box-shadow:0 3px 0 #080d12}.throttle-gauge,.fuel-gauge{background:#0e2c46;border:1px solid #28506f;border-radius:12px;padding:11px;margin-top:10px}.throttle-gauge span,.fuel-gauge span,.fuel-gauge small{display:block}.throttle-gauge strong,.fuel-gauge strong{font-size:1.12rem}.throttle-gauge>div{height:10px;background:#1c425e;border-radius:999px;overflow:hidden;margin-top:7px}.throttle-gauge i{display:block;width:0;height:100%;background:#54d54d;transition:.2s}.fuel-gauge small{color:#8facbf;font-size:.66rem;margin-top:4px}.pedal-presets{display:grid;grid-template-columns:repeat(3,1fr);gap:5px;margin-top:12px}.pedal-presets button{background:#153853;color:#fff;border:1px solid #315f80;border-radius:8px;padding:8px 3px;font-weight:900;cursor:pointer}.pedal-presets small{display:block;font-size:.55rem;color:#9eb5c8;font-weight:600;margin-top:3px}.pedal-presets button.active{outline:2px solid #18bcff;background:#0d5d91}.engine-cutaway{min-height:520px;position:relative;border-radius:18px;overflow:hidden;background:radial-gradient(circle at 60% 40%,#24384c 0,#111f2d 35%,#08131e 76%);border:1px solid #32516c}.fuel-tank-visual{position:absolute;left:4%;bottom:9%;width:170px;height:115px;border:5px solid #63717a;border-radius:22px 22px 12px 12px;background:#242d33;overflow:hidden}.fuel-tank-visual span{position:absolute;z-index:3;top:10px;left:12px;font-size:.72rem;font-weight:900}.fuel-liquid{position:absolute;left:0;right:0;bottom:0;height:48%;background:linear-gradient(#ffd648,#d69308);box-shadow:0 0 24px rgba(255,190,20,.5)}.fuel-pump-visual{position:absolute;left:22%;bottom:28%;width:95px;height:42px;background:linear-gradient(#9aa3aa,#4c5962);border-radius:18px;border:3px solid #bfc6cc;display:grid;place-items:center;font-size:.62rem;font-weight:900;z-index:4}.fuel-pipe-visual{position:absolute;left:15%;bottom:35%;width:39%;height:14px;border-radius:999px;background:#604b16;border:3px solid #c18a13;transform:rotate(-11deg);transform-origin:left}.fuel-pipe-visual i{position:absolute;width:11px;height:11px;background:#ffd52f;border-radius:50%;top:-1px;left:0;opacity:0}.engine-cutaway.fueling .fuel-pipe-visual i{animation:fuelTravel .9s linear infinite}.engine-cutaway.fueling .fuel-pipe-visual i:nth-child(2){animation-delay:.2s}.engine-cutaway.fueling .fuel-pipe-visual i:nth-child(3){animation-delay:.4s}.engine-cutaway.fueling .fuel-pipe-visual i:nth-child(4){animation-delay:.6s}@keyframes fuelTravel{0%{left:0;opacity:.1}20%{opacity:1}100%{left:92%;opacity:.2}}.air-intake-visual{position:absolute;left:5%;top:12%;width:42%;height:72px;border:7px solid #2769a2;border-radius:35px;background:linear-gradient(90deg,#153c61,#1597e7);transform:rotate(7deg);box-shadow:0 0 18px rgba(40,157,240,.28)}.air-intake-visual span{position:absolute;left:10px;top:20px;font-weight:900;font-size:.72rem}.air-intake-visual i{position:absolute;width:10px;height:10px;border-radius:50%;background:#8bdbff;top:25px;left:22%;opacity:.25}.engine-cutaway.fueling .air-intake-visual i{animation:airTravel 1s linear infinite}.engine-cutaway.fueling .air-intake-visual i:nth-child(3){animation-delay:.3s}.engine-cutaway.fueling .air-intake-visual i:nth-child(4){animation-delay:.6s}@keyframes airTravel{to{left:88%;opacity:1}}.injector-visual{position:absolute;left:50%;top:18%;width:90px;height:34px;border-radius:10px;background:#7f8990;border:3px solid #b8c0c5;z-index:7;transform:rotate(12deg)}.injector-visual span{position:absolute;top:-28px;left:-8px;font-size:.68rem;background:#0b2237;border:1px solid #69a5d0;padding:5px 7px;border-radius:7px;white-space:nowrap}.injector-visual b{position:absolute;right:-10px;bottom:-18px;width:8px;height:24px;background:#e2ad2f;transform:rotate(-18deg)}.spark-visual{position:absolute;left:64%;top:4%;text-align:center;font-size:.68rem;font-weight:900;z-index:8}.spark-visual b{display:block;font-size:2rem;opacity:.25}.engine-cutaway.igniting .spark-visual b{animation:carSpark .25s ease 3}@keyframes carSpark{50%{opacity:1;transform:scale(1.45)}}.engine-cylinder{position:absolute;left:47%;top:25%;width:210px;height:255px;border:14px solid #65717b;border-top-width:18px;border-radius:20px 20px 8px 8px;background:linear-gradient(#263440 0 8%,#d8dde0 8% 100%);overflow:hidden;z-index:5}.mix-cloud{position:absolute;left:15px;right:15px;top:15px;height:80px}.mix-cloud i{position:absolute;width:10px;height:10px;border-radius:50%;background:#7fd4ff;opacity:0}.mix-cloud i:nth-child(even){background:#ffd137}.engine-cutaway.fueling .mix-cloud i{animation:mixFloat 1.2s ease-in-out infinite}.mix-cloud i:nth-child(1){left:15%;top:15%}.mix-cloud i:nth-child(2){left:27%;top:42%;animation-delay:.1s}.mix-cloud i:nth-child(3){left:42%;top:22%;animation-delay:.2s}.mix-cloud i:nth-child(4){left:54%;top:55%;animation-delay:.3s}.mix-cloud i:nth-child(5){left:67%;top:15%;animation-delay:.4s}.mix-cloud i:nth-child(6){left:79%;top:40%;animation-delay:.5s}.mix-cloud i:nth-child(7){left:33%;top:68%;animation-delay:.6s}.mix-cloud i:nth-child(8){left:70%;top:70%;animation-delay:.7s}@keyframes mixFloat{0%,100%{opacity:.25;transform:translateY(4px)}50%{opacity:1;transform:translateY(-6px)}}.mini-explosion{position:absolute;top:27px;left:50%;transform:translateX(-50%) scale(.2);font-size:4rem;opacity:0}.engine-cutaway.igniting .mini-explosion{animation:controlledBoom .7s ease-out}@keyframes controlledBoom{0%{opacity:.1;transform:translateX(-50%) scale(.2)}42%{opacity:1;transform:translateX(-50%) scale(1.4)}100%{opacity:.4;transform:translateX(-50%) scale(.65)}}.cutaway-piston{position:absolute;left:16px;right:16px;top:105px;height:82px;background:linear-gradient(#d8dde0,#7a848c);border:3px solid #505c66;border-radius:9px;display:grid;place-items:center;color:#25313b;font-size:.72rem;font-weight:950;transition:.35s}.engine-cutaway.powerstroke .cutaway-piston{transform:translateY(50px)}.cutaway-rod{position:absolute;left:50%;top:184px;width:13px;height:100px;background:#777f86;transform:translateX(-50%)}.cutaway-crank{position:absolute;left:49%;bottom:5%;width:205px;height:25px;background:#5b6872;border-radius:999px;z-index:4}.cutaway-crank i{position:absolute;left:78px;top:-24px;width:62px;height:62px;border:14px solid #727e87;border-radius:50%}.cutaway-crank span{position:absolute;top:35px;left:60px;font-size:.7rem;font-weight:900}.engine-cutaway.powerstroke .cutaway-crank{animation:crankOne .8s ease-out}@keyframes crankOne{to{transform:rotate(180deg)}}.engine-callout{position:absolute;background:#0b2238;border:1px solid #58a9df;border-radius:8px;padding:5px 8px;font-size:.66rem;font-weight:900;z-index:10}.air-callout{left:26%;top:6%;color:#8ddcff}.fuel-callout{left:31%;bottom:42%;color:#ffd949}.power-callout{right:8%;top:52%;color:#ffbc39;opacity:0}.engine-cutaway.powerstroke .power-callout{opacity:1}.engine-steps{display:flex;flex-direction:column;gap:9px}.engine-step{display:grid;grid-template-columns:34px 1fr;gap:2px 9px;background:#f8fbff;color:#10233a;border:1px solid #cbdbe8;border-radius:12px;padding:10px;text-align:left;cursor:pointer}.engine-step b{grid-row:1/3}.engine-step span{font-weight:950}.engine-step small{color:#52677c}.engine-step.active{background:#05a6ef;color:#fff;border-color:#40dcff;box-shadow:0 0 0 2px rgba(37,214,255,.28)}.engine-step.active small{color:#e4f8ff}.engine-popup{position:absolute;right:24px;top:95px;width:min(440px,calc(100% - 48px));background:#fff;color:#10233a;border:4px solid #198bf1;border-radius:20px;padding:20px 20px 17px;z-index:30;box-shadow:0 18px 60px rgba(0,0,0,.35);display:grid;grid-template-columns:44px 1fr;gap:12px}.engine-popup[hidden]{display:none}.popup-number{width:42px;height:42px;border-radius:50%;display:grid;place-items:center;background:#1589f1;color:#fff;font-size:1.3rem;font-weight:950}.popup-copy h3{font-size:1.18rem;margin:2px 35px 10px 0}.popup-copy p{color:#31485e}.popup-close{position:absolute;right:14px;top:11px;border:0;background:transparent;font-size:2rem;color:#16334e;cursor:pointer}.popup-power{display:flex;gap:10px;align-items:flex-start;background:#e9f5ff;border-radius:12px;padding:12px;margin-top:13px}.popup-power>span{font-size:2rem}.popup-power p{margin:0}.popup-actions{display:flex;justify-content:space-between;margin-top:14px}.cutaway-bigidea{display:flex;gap:12px;background:#fff6ce;color:#314150;border-radius:13px;padding:13px 15px;margin-top:15px}.cutaway-bigidea span{font-size:1.5rem}.cutaway-bigidea p{margin:0}.car-cutaway .blue-text{color:#55baff}@media(max-width:1050px){.cutaway-grid{grid-template-columns:180px 1fr}.engine-steps{grid-column:1/-1;display:grid;grid-template-columns:repeat(5,1fr)}.engine-step{grid-template-columns:30px 1fr}.engine-step small{display:none}}@media(max-width:760px){.car-cutaway{padding:18px}.cutaway-head{flex-direction:column}.cutaway-grid{grid-template-columns:1fr}.pedal-console{display:grid;grid-template-columns:130px 1fr;gap:8px;align-items:center}.console-step,.pedal-presets{grid-column:1/-1}.real-pedal{height:145px;margin:5px auto}.pedal-grooves{height:105px}.engine-cutaway{min-height:480px}.engine-steps{grid-template-columns:1fr}.engine-step small{display:block}.engine-popup{position:fixed;left:14px;right:14px;top:12vh;width:auto;max-height:76vh;overflow:auto}.fuel-tank-visual{width:135px}.engine-cylinder{left:44%;width:170px}.cutaway-crank{left:43%;width:180px}.air-intake-visual{width:39%}}@media(max-width:480px){.pedal-console{grid-template-columns:1fr}.engine-cutaway{min-height:510px}.fuel-tank-visual{left:2%;width:120px}.fuel-pump-visual{left:19%}.engine-cylinder{left:36%;top:28%;width:160px}.injector-visual{left:39%}.spark-visual{left:65%}.cutaway-crank{left:35%;bottom:7%}.air-intake-visual{left:2%;width:42%}.fuel-pipe-visual{left:11%;width:35%}.pedal-presets{grid-template-columns:repeat(3,1fr)}}

/* v5.3 exact approved car simulation */
.car-cutaway-v53{background:#071b31;color:#fff;border-radius:26px;padding:24px;margin:34px 0;box-shadow:0 18px 48px rgba(8,28,52,.24)}
.car-v53-head{display:flex;justify-content:space-between;gap:18px;align-items:flex-start}
.car-v53-head h2{color:#fff;margin:.15rem 0 .35rem}.car-v53-head p{color:#c7d8e8;max-width:760px}
.car53-layout{display:grid;grid-template-columns:190px minmax(460px,1fr) 300px;gap:14px;margin-top:18px;align-items:stretch}
.car53-controls,.car53-explain{background:#0b2942;border:1px solid #235272;border-radius:18px;padding:16px}
.car53-controls h3{margin:0 0 4px}.car53-controls p{color:#c9d9e8;font-size:.88rem}
.car53-pedal{width:100px;height:180px;display:block;margin:16px auto;background:transparent;border:0;cursor:pointer;touch-action:none}
.car53-pedal span{display:grid;place-items:center;width:70px;height:140px;margin:auto;background:linear-gradient(145deg,#465461,#151d25);border:3px solid #8d99a4;border-radius:14px;color:#a7b2bc;font-size:3rem;box-shadow:0 12px 0 #05090d;transform-origin:bottom;transition:.12s}
.car53-pedal.pressed span{transform:perspective(230px) rotateX(18deg) translateY(10px);box-shadow:0 3px 0 #05090d}
.car53-gauge,.car53-fuel{background:#0f3552;border:1px solid #2a5879;border-radius:12px;padding:10px;margin-top:10px}.car53-gauge span,.car53-fuel span,.car53-fuel small{display:block}.car53-gauge strong,.car53-fuel strong{font-size:1.1rem}.car53-gauge>div{height:10px;background:#173f5c;border-radius:999px;overflow:hidden;margin-top:7px}.car53-gauge i{display:block;height:100%;width:0;background:#53d84c;transition:.2s}.car53-fuel small{color:#92a9bb;font-size:.66rem;margin-top:3px}
.car53-presets{display:grid;grid-template-columns:repeat(3,1fr);gap:5px;margin-top:12px}.car53-presets button{background:#133b59;border:1px solid #316684;color:#fff;border-radius:9px;padding:8px 2px;font-weight:900;cursor:pointer}.car53-presets small{display:block;color:#9fb6c8;font-size:.55rem;margin-top:3px}.car53-presets button.active{background:#0b76be;outline:2px solid #19c3ff}
.car53-engine{position:relative;overflow:hidden;border-radius:18px;min-height:520px;background:#06111b;border:1px solid #31516b}
.car53-engine>img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;object-position:center;filter:brightness(.86) saturate(.95)}
.car53-overlay{position:absolute;inset:0;pointer-events:none}
.car53-air,.car53-gas,.car53-spray,.car53-fire,.car53-piston-ring,.car53-crank-ring{position:absolute;opacity:0;transition:.2s}
.car53-air{left:6%;top:27%;width:47%;height:13px;border-radius:999px;background:linear-gradient(90deg,transparent,#25b4ff,#b6ecff,transparent);box-shadow:0 0 18px #168cd7;transform:rotate(4deg)}
.car53-gas{left:16%;top:60%;width:45%;height:8px;border-radius:999px;background:linear-gradient(90deg,transparent,#ffd72f,#fff1a0,#ffd72f,transparent);box-shadow:0 0 14px #ffbf1c;transform:rotate(-17deg)}
.car53-spray{left:58%;top:34%;width:80px;height:95px;background:radial-gradient(ellipse at top,#ffe049 0 10%,rgba(255,211,51,.55) 28%,transparent 70%);clip-path:polygon(42% 0,58% 0,100% 100%,0 100%)}
.car53-spark{left:62%;top:28%;font-size:2.2rem}
.car53-fire{left:55%;top:39%;width:120px;height:120px;border-radius:50%;background:radial-gradient(circle,#fffad0 0 10%,#ffd52a 24%,#ff7a17 50%,rgba(255,73,0,.3) 70%,transparent 74%);box-shadow:0 0 38px #ff8b18;transform:scale(.25)}
.car53-piston-ring{left:56%;top:55%;width:100px;height:78px;border:5px solid #ffd12c;border-radius:9px}
.car53-crank-ring{left:53%;bottom:8%;width:125px;height:125px;border:5px solid #ffbb2e;border-radius:50%}
.car53-engine.stage2 .car53-air,.car53-engine.stage2 .car53-gas,.car53-engine.stage2 .car53-spray,.car53-engine.stage3 .car53-air,.car53-engine.stage3 .car53-gas,.car53-engine.stage3 .car53-spray,.car53-engine.stage4 .car53-air,.car53-engine.stage4 .car53-gas,.car53-engine.stage4 .car53-spray,.car53-engine.stage5 .car53-air,.car53-engine.stage5 .car53-gas{opacity:1}
.car53-engine.stage2 .car53-air,.car53-engine.stage2 .car53-gas,.car53-engine.stage3 .car53-air,.car53-engine.stage3 .car53-gas,.car53-engine.stage4 .car53-air,.car53-engine.stage4 .car53-gas,.car53-engine.stage5 .car53-air,.car53-engine.stage5 .car53-gas{animation:car53Flow .7s linear infinite}
.car53-engine.stage3 .car53-spark{opacity:1;animation:car53Spark .28s ease 3}.car53-engine.stage3 .car53-fire,.car53-engine.stage4 .car53-fire{opacity:1;animation:car53Boom .7s ease-out}
.car53-engine.stage4 .car53-piston-ring{opacity:1;animation:car53Piston .65s ease forwards}.car53-engine.stage5 .car53-crank-ring{opacity:1;animation:car53Crank .8s linear}
@keyframes car53Flow{50%{filter:brightness(1.8)}}
@keyframes car53Spark{50%{transform:scale(1.5);filter:brightness(2)}}
@keyframes car53Boom{0%{transform:scale(.2);opacity:.2}45%{transform:scale(1.3);opacity:1}100%{transform:scale(.8);opacity:.75}}
@keyframes car53Piston{to{transform:translateY(60px)}}
@keyframes car53Crank{to{transform:rotate(180deg)}}
.car53-label{position:absolute;z-index:5;background:rgba(5,23,39,.9);border:1px solid #74b9e7;border-radius:8px;padding:5px 7px;font-size:.66rem;font-weight:900}.label-air{left:20%;top:14%}.label-injector{left:47%;top:27%}.label-spark{left:65%;top:12%}.label-piston{left:67%;top:58%}.label-crank{left:58%;bottom:5%}
.car53-what{display:flex;gap:10px;background:#eaf5ff;color:#10243b;border-radius:13px;padding:12px}.idea-icon{font-size:1.6rem}.car53-what h3{margin:0 0 4px}.car53-what p{font-size:.82rem;margin:0;color:#324b63;line-height:1.42}
.car53-steps{display:grid;gap:8px;margin-top:12px}.car53-step{display:grid;grid-template-columns:36px 1fr;gap:8px;background:#102f49;border:1px solid #2b5473;border-radius:12px;padding:10px;opacity:.7}.car53-step b{width:34px;height:34px;border-radius:50%;display:grid;place-items:center;border:2px solid #8ea9bd}.car53-step strong,.car53-step small{display:block}.car53-step small{color:#b5c7d6;font-size:.69rem;margin-top:2px}.car53-step.active{background:#08a5ed;border-color:#48d9ff;opacity:1;box-shadow:0 0 0 2px rgba(55,211,255,.22)}.car53-step.active b{background:#096cc4;border-color:#69dfff}
.car53-key{margin-top:12px;border:1px solid #20526f;border-radius:12px;padding:12px}.car53-key strong{color:#fff}.car53-key p{font-size:.72rem;color:#afc2d1;margin:.35rem 0 0}
.car-cutaway-v53 .blue-text{color:#55baff}
@media(max-width:1100px){.car53-layout{grid-template-columns:180px 1fr}.car53-explain{grid-column:1/-1}.car53-steps{grid-template-columns:repeat(5,1fr)}.car53-step{grid-template-columns:1fr}.car53-step b{margin:auto}.car53-step small{display:none}}
@media(max-width:760px){.car-cutaway-v53{padding:16px}.car-v53-head{flex-direction:column}.car53-layout{grid-template-columns:1fr}.car53-controls{display:grid;grid-template-columns:130px 1fr;gap:8px;align-items:center}.car53-controls h3,.car53-controls>p,.car53-presets{grid-column:1/-1}.car53-pedal{height:145px}.car53-pedal span{height:105px}.car53-engine{min-height:390px}.car53-explain{grid-column:auto}.car53-steps{grid-template-columns:1fr}.car53-step{grid-template-columns:36px 1fr}.car53-step small{display:block}.car53-label{font-size:.55rem}.label-piston{left:64%}.label-crank{left:55%}}

/* v5.4 simplified moving car engine */
.car-simple{background:#081c31;color:#fff;border-radius:26px;padding:24px;margin:34px 0;box-shadow:0 18px 46px rgba(9,28,48,.24)}
.car-simple-head{display:flex;justify-content:space-between;gap:18px;align-items:flex-start}.car-simple-head h2{color:#fff;margin:.15rem 0 .35rem}.car-simple-head p{color:#c8d9e8;max-width:760px}.car-simple .blue-text{color:#56b8ff}
.car-simple-grid{display:grid;grid-template-columns:190px minmax(430px,1fr) 300px;gap:14px;margin-top:18px}
.car-simple-controls,.car-simple-steps{background:#0d2c46;border:1px solid #28516e;border-radius:18px;padding:16px}.car-simple-controls h3{margin:0 0 4px}.car-simple-controls p{color:#c4d5e4;font-size:.88rem}
.car-simple-presets{display:grid;grid-template-columns:repeat(3,1fr);gap:5px;margin:12px 0}.car-simple-presets button{background:#153a56;color:#fff;border:1px solid #35617f;border-radius:9px;padding:8px 3px;font-weight:900;cursor:pointer}.car-simple-presets small{display:block;color:#9fb7c9;font-size:.55rem}.car-simple-presets button.active{background:#0a7bc5;outline:2px solid #21c9ff}
.car-simple-pedal{width:100px;height:175px;display:block;margin:8px auto;background:transparent;border:0;cursor:pointer}.car-simple-pedal span{display:grid;place-items:center;width:70px;height:138px;margin:auto;background:linear-gradient(145deg,#485561,#171e25);border:3px solid #929ca5;border-radius:14px;color:#9eabb4;font-size:3rem;box-shadow:0 12px 0 #060a0e;transition:.12s;transform-origin:bottom}.car-simple-pedal.pressed span{transform:perspective(220px) rotateX(19deg) translateY(9px);box-shadow:0 3px 0 #060a0e}
.car-simple-meter,.car-simple-fuel{background:#103653;border:1px solid #2f5d7a;border-radius:12px;padding:10px;margin-top:9px}.car-simple-meter span,.car-simple-fuel span,.car-simple-fuel small{display:block}.car-simple-meter strong,.car-simple-fuel strong{font-size:1.1rem}.car-simple-meter>div{height:10px;background:#1c455f;border-radius:999px;overflow:hidden;margin-top:7px}.car-simple-meter i{display:block;width:0;height:100%;background:#50db4d;transition:.2s}.car-simple-fuel small{color:#91a9bb;font-size:.66rem}
.car-engine-diagram{position:relative;min-height:520px;border-radius:18px;overflow:hidden;background:radial-gradient(circle at 61% 38%,#284158 0,#142638 37%,#08141f 76%);border:1px solid #33546f}
.air-intake-simple{position:absolute;left:5%;top:15%;width:49%;height:82px;border:8px solid #3178b3;border-radius:42px;background:linear-gradient(90deg,#153f67,#1598e9);box-shadow:0 0 18px rgba(55,171,244,.25)}.air-intake-simple span{position:absolute;left:20px;top:-30px;background:#0c263c;border:1px solid #6dadd8;border-radius:7px;padding:5px 7px;font-size:.68rem;font-weight:900}.air-arrow{position:absolute;top:16px;color:#d3f2ff;font-size:2.2rem;opacity:0}.a1{left:18%}.a2{left:46%}.a3{left:74%}
.fuel-tank-simple{position:absolute;left:4%;bottom:8%;width:190px;height:128px;border:6px solid #66737d;border-radius:24px 24px 13px 13px;background:#263039;overflow:hidden}.fuel-tank-simple .gasoline{position:absolute;left:0;right:0;bottom:0;height:52%;background:linear-gradient(#ffd74a,#d99a0e);box-shadow:0 0 24px rgba(255,193,31,.5)}.fuel-tank-simple span{position:absolute;left:16px;bottom:17px;font-size:.72rem;font-weight:900;z-index:2}
.fuel-line-simple{position:absolute;left:19%;bottom:34%;width:41%;height:14px;background:#655017;border:3px solid #c9921a;border-radius:999px;transform:rotate(-14deg);transform-origin:left}.fuel-line-simple i{position:absolute;width:12px;height:12px;border-radius:50%;background:#ffd62c;top:-1px;left:0;opacity:0}
.injector-simple{position:absolute;left:51%;top:31%;width:95px;height:34px;border-radius:10px;background:#7b858d;border:3px solid #bac2c7;transform:rotate(10deg);z-index:7}.injector-simple span{position:absolute;top:-29px;left:-11px;background:#0c263c;border:1px solid #6dadd8;padding:5px 7px;border-radius:7px;font-size:.67rem;font-weight:900;white-space:nowrap}.injector-simple b{position:absolute;right:-8px;bottom:-18px;width:7px;height:23px;background:#dba928;transform:rotate(-19deg)}
.sparkplug-simple{position:absolute;left:64%;top:7%;font-size:.68rem;font-weight:900;text-align:center;z-index:8}.sparkplug-simple span{display:block;background:#0c263c;border:1px solid #6dadd8;padding:5px 7px;border-radius:7px}.sparkplug-simple b{display:block;font-size:2rem;opacity:.25}
.cylinder-simple{position:absolute;left:48%;top:24%;width:220px;height:260px;border:15px solid #65717b;border-top-width:18px;border-radius:22px 22px 8px 8px;background:linear-gradient(#26333d 0 8%,#dce1e4 8% 100%);overflow:hidden;z-index:5}.mix-dots{position:absolute;left:17px;right:17px;top:18px;height:80px}.mix-dots i{position:absolute;width:10px;height:10px;border-radius:50%;opacity:0}.mix-dots .blue{background:#73d3ff}.mix-dots .yellow{background:#ffd431}.mix-dots i:nth-child(1){left:16%;top:14%}.mix-dots i:nth-child(2){left:30%;top:42%}.mix-dots i:nth-child(3){left:48%;top:20%}.mix-dots i:nth-child(4){left:60%;top:56%}.mix-dots i:nth-child(5){left:73%;top:15%}.mix-dots i:nth-child(6){left:81%;top:50%}
.combustion-simple{position:absolute;left:50%;top:31px;width:105px;height:105px;transform:translateX(-50%) scale(.2);border-radius:50%;background:radial-gradient(circle,#fffbd0 0 12%,#ffd426 26%,#ff7b18 54%,rgba(255,64,0,.28) 72%,transparent 74%);box-shadow:0 0 34px #ff8b1d;opacity:0}
.piston-simple{position:absolute;left:18px;right:18px;top:108px;height:84px;background:linear-gradient(#dfe4e7,#7b858d);border:3px solid #505c66;border-radius:9px;display:grid;place-items:center;color:#26333c;font-size:.72rem;font-weight:950;transition:.28s}.rod-simple{position:absolute;left:50%;top:185px;width:14px;height:105px;background:#788188;transform:translateX(-50%);transform-origin:top;transition:.28s}
.crank-simple{position:absolute;left:49%;bottom:5%;width:210px;height:150px;z-index:4}.crank-disc{position:absolute;left:48px;bottom:8px;width:122px;height:122px;border:18px solid #707b84;border-radius:50%;background:#303b43}.crank-pin{position:absolute;left:100px;bottom:56px;width:24px;height:24px;border-radius:50%;background:#b5bec5;border:5px solid #57636c}.crank-simple span{position:absolute;left:65px;bottom:-5px;font-size:.7rem;font-weight:900}
.exhaust-simple{position:absolute;right:3%;top:21%;width:22%;height:70px;border:8px solid #a14a32;border-radius:35px;background:linear-gradient(90deg,#75331f,#ee6d32)}.exhaust-simple span{position:absolute;right:12px;top:-30px;background:#0c263c;border:1px solid #6dadd8;padding:5px 7px;border-radius:7px;font-size:.67rem;font-weight:900}.exhaust-arrow{position:absolute;top:13px;color:#ffd7c8;font-size:2rem;opacity:0}.e1{left:25%}.e2{left:62%}
.car-engine-diagram.running .air-arrow{opacity:1;animation:simpleArrow .7s linear infinite}.car-engine-diagram.running .air-arrow.a2{animation-delay:.18s}.car-engine-diagram.running .air-arrow.a3{animation-delay:.36s}
.car-engine-diagram.running .fuel-line-simple i{opacity:1;animation:simpleFuel .8s linear infinite}.car-engine-diagram.running .fuel-line-simple i:nth-child(2){animation-delay:.2s}.car-engine-diagram.running .fuel-line-simple i:nth-child(3){animation-delay:.4s}.car-engine-diagram.running .fuel-line-simple i:nth-child(4){animation-delay:.6s}
.car-engine-diagram.running .mix-dots i{opacity:1;animation:simpleMix .8s ease-in-out infinite}.car-engine-diagram.running .sparkplug-simple b{animation:simpleSpark .8s steps(1) infinite}.car-engine-diagram.running .combustion-simple{animation:simpleBoom .8s ease-out infinite}.car-engine-diagram.running .piston-simple{animation:simplePiston .8s ease-in-out infinite}.car-engine-diagram.running .rod-simple{animation:simpleRod .8s ease-in-out infinite}.car-engine-diagram.running .crank-simple{animation:simpleCrank .8s linear infinite}.car-engine-diagram.running .exhaust-arrow{opacity:1;animation:simpleArrow .7s linear infinite}
@keyframes simpleArrow{0%{transform:translateX(-12px);opacity:.25}100%{transform:translateX(22px);opacity:1}}
@keyframes simpleFuel{0%{left:0;opacity:.15}100%{left:92%;opacity:1}}
@keyframes simpleMix{50%{transform:translateY(-8px);filter:brightness(1.4)}}
@keyframes simpleSpark{0%,54%{opacity:.2}55%,68%{opacity:1}69%,100%{opacity:.2}}
@keyframes simpleBoom{0%,48%{opacity:0;transform:translateX(-50%) scale(.2)}55%{opacity:1;transform:translateX(-50%) scale(1.25)}100%{opacity:.15;transform:translateX(-50%) scale(.7)}}
@keyframes simplePiston{0%,45%{transform:translateY(0)}72%,100%{transform:translateY(55px)}}
@keyframes simpleRod{0%,45%{transform:translateX(-50%) rotate(0deg)}72%{transform:translateX(-50%) rotate(12deg)}100%{transform:translateX(-50%) rotate(0deg)}}
@keyframes simpleCrank{to{transform:rotate(360deg)}}
.car-simple-steps{display:grid;gap:8px}.simple-step{display:grid;grid-template-columns:38px 1fr;gap:8px;background:#f8fbff;color:#10233a;border-radius:13px;padding:10px;border:1px solid #cadbe8;opacity:.76}.simple-step b{width:36px;height:36px;border-radius:50%;display:grid;place-items:center;background:#1887ef;color:#fff;font-size:1.1rem}.simple-step strong,.simple-step small{display:block}.simple-step small{color:#556b7e;font-size:.7rem;margin-top:2px}.simple-step.active{opacity:1;outline:3px solid #12c6ff;background:#ecfaff}.simple-what{background:#e9f5ff;color:#10243b;border-radius:13px;padding:12px;margin-top:2px}.simple-what p{margin:.35rem 0 0;color:#334c62;font-size:.78rem}
@media(max-width:1080px){.car-simple-grid{grid-template-columns:180px 1fr}.car-simple-steps{grid-column:1/-1;grid-template-columns:repeat(5,1fr)}.simple-what{grid-column:1/-1}.simple-step{grid-template-columns:1fr}.simple-step b{margin:auto}.simple-step small{display:none}}
@media(max-width:760px){.car-simple{padding:16px}.car-simple-head{flex-direction:column}.car-simple-grid{grid-template-columns:1fr}.car-simple-controls{display:grid;grid-template-columns:125px 1fr;gap:8px;align-items:center}.car-simple-controls h3,.car-simple-controls>p,.car-simple-presets{grid-column:1/-1}.car-simple-pedal{height:145px}.car-simple-pedal span{height:105px}.car-engine-diagram{min-height:430px}.car-simple-steps{grid-column:auto;grid-template-columns:1fr}.simple-step{grid-template-columns:38px 1fr}.simple-step small{display:block}.cylinder-simple{left:43%;width:180px}.crank-simple{left:42%}.fuel-tank-simple{width:150px}.air-intake-simple{width:43%}.exhaust-simple{width:20%}}

/* v5.5 common flagship balance: simple enough for sixth grade, real enough to show mechanism */
.flagship-simple{background:#081c31;color:#fff;border-radius:26px;padding:24px;margin:34px 0;box-shadow:0 18px 46px rgba(9,28,48,.24)}
.flagship-head{display:flex;justify-content:space-between;gap:18px;align-items:flex-start}.flagship-head h2{color:#fff;margin:.15rem 0 .35rem}.flagship-head p{color:#c7d8e8;max-width:760px}.flagship-simple .blue-text{color:#56b8ff}
.flagship-grid{display:grid;grid-template-columns:190px minmax(430px,1fr) 300px;gap:14px;margin-top:18px}
.simple-controls,.simple-steps-panel{background:#0d2c46;border:1px solid #28516e;border-radius:18px;padding:16px}.simple-controls h3{margin:0 0 10px}
.simple-controls label{display:grid;grid-template-columns:auto 1fr auto;gap:8px;align-items:center;background:#103653;border:1px solid #2f5d7a;border-radius:12px;padding:10px;margin:9px 0;font-weight:850}.simple-controls output{color:#6bc6ff}
.mini-readout{background:#103653;border:1px solid #2f5d7a;border-radius:12px;padding:10px;margin-top:12px}.mini-readout span,.mini-readout strong{display:block}.mini-readout strong{font-size:1.15rem}
.simple-steps-panel{display:grid;gap:8px}.simple-steps-panel .simple-step{display:grid;grid-template-columns:38px 1fr;gap:8px;background:#f8fbff;color:#10233a;border-radius:13px;padding:10px;border:1px solid #cadbe8;opacity:.76}.simple-steps-panel .simple-step b{width:36px;height:36px;border-radius:50%;display:grid;place-items:center;background:#1887ef;color:#fff}.simple-steps-panel .simple-step strong,.simple-steps-panel .simple-step small{display:block}.simple-steps-panel .simple-step small{color:#556b7e;font-size:.7rem;margin-top:2px}.simple-steps-panel .simple-step.active{opacity:1;outline:3px solid #12c6ff;background:#ecfaff}.simple-steps-panel .simple-what{background:#e9f5ff;color:#10243b;border-radius:13px;padding:12px}.simple-steps-panel .simple-what p{margin:.35rem 0 0;color:#334c62;font-size:.78rem}

/* airplane */
.air-simple-stage{position:relative;min-height:500px;border-radius:18px;overflow:hidden;background:linear-gradient(#bfe5ff 0 68%,#d0e5b5 68%);border:1px solid #33546f}
.air-simple-wing{position:absolute;left:38%;top:43%;width:190px;height:44px;background:linear-gradient(#f0f2f4,#7b858d);border-radius:55% 40% 45% 45%;transform-origin:center;box-shadow:0 4px 0 #515c66}.air-simple-wing span{position:absolute;top:-27px;left:68px;background:#0c263c;color:#fff;padding:4px 6px;border-radius:6px;font-size:.65rem;font-weight:900}
.plane-body-simple{position:absolute;left:39%;top:33%;font-size:5.5rem;transition:.25s}.airflow{position:absolute;left:8%;right:12%;display:flex;justify-content:space-around;color:#168bd5;font-size:2.2rem;opacity:.7}.airflow.top{top:28%}.airflow.bottom{top:57%}.airflow i{font-style:normal;animation:airMove 1s linear infinite}.airflow i:nth-child(2){animation-delay:.2s}.airflow i:nth-child(3){animation-delay:.4s}.force-arrow{position:absolute;font-weight:950;color:#173d70;font-size:2.2rem;text-align:center}.force-arrow span{display:block;font-size:.7rem}.lift-force{left:55%;top:10%}.weight-force{left:55%;bottom:8%}.drag-force{left:22%;top:44%}@keyframes airMove{0%{transform:translateX(-20px);opacity:.25}100%{transform:translateX(30px);opacity:1}}

/* solar */
.solar-simple-stage{position:relative;min-height:500px;border-radius:18px;overflow:hidden;background:linear-gradient(#cceaff 0 34%,#eef4f8 34%);border:1px solid #33546f}.sun-simple{position:absolute;left:7%;top:20px;font-size:4.7rem}.photon-simple{position:absolute;left:19%;top:85px;width:42%;height:120px;transform:rotate(18deg)}.photon-simple i{position:absolute;width:13px;height:13px;border-radius:50%;background:#ffd52c;box-shadow:0 0 10px #ffd52c;animation:photonMove 1.1s linear infinite}.photon-simple i:nth-child(1){left:5%;top:5%}.photon-simple i:nth-child(2){left:25%;top:35%;animation-delay:.2s}.photon-simple i:nth-child(3){left:45%;top:12%;animation-delay:.4s}.photon-simple i:nth-child(4){left:65%;top:48%;animation-delay:.6s}.photon-simple i:nth-child(5){left:83%;top:20%;animation-delay:.8s}@keyframes photonMove{from{transform:translate(-55px,-45px);opacity:.1}to{transform:translate(60px,70px);opacity:1}}
.cell-layer{position:absolute;left:20%;right:24%;height:92px;color:#fff;padding:12px 14px;font-weight:900}.cell-layer.n{top:205px;background:linear-gradient(135deg,#1268a9,#2d93d0)}.cell-junction{position:absolute;left:20%;right:24%;top:297px;height:32px;background:#dce6ec;color:#324a60;text-align:center;padding-top:7px;font-size:.7rem;font-weight:950}.cell-layer.p{top:329px;background:linear-gradient(135deg,#9e3e58,#d35e72)}.electron-dot,.hole-dot{position:absolute;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;border:2px solid #fff}.electron-dot{background:#0b75d8}.hole-dot{background:#ed4f5e}.e1{left:38%;top:20%}.e2{left:59%;top:48%}.e3{left:78%;top:18%}.h1{left:43%;top:16%}.h2{left:65%;top:47%}.h3{left:82%;top:20%}
.wire-simple{position:absolute;right:5%;top:220px;width:18%;height:180px;border:6px solid #e7aa16;border-left:0;border-radius:0 22px 22px 0}.wire-simple>i{position:absolute;width:25px;height:25px;border-radius:50%;background:#fff;border:2px solid #0b78df;color:#0870ca;text-align:center;font-style:normal;font-weight:950;animation:electronFlow 2s linear infinite}.wire-simple>i:nth-child(1){top:-14px;left:8%}.wire-simple>i:nth-child(2){right:-14px;top:35%}.wire-simple>i:nth-child(3){bottom:-14px;left:35%}.bulb-simple{position:absolute;right:-28px;top:57px;font-size:3.8rem;filter:grayscale(1);transition:.25s}@keyframes electronFlow{50%{transform:translateY(25px)}}

/* iPad */
.ipad-simple-device{height:235px;width:150px;margin:0 auto;display:block;border:9px solid #20242c;border-radius:24px;background:linear-gradient(135deg,#d7edff,#f2eaff);font:inherit;font-weight:950;color:#145a9d;position:relative;cursor:pointer}.ipad-simple-device i{position:absolute;left:50%;top:50%;width:28px;height:28px;border:3px solid #0b78df;border-radius:50%;transform:translate(-50%,-50%) scale(.2);opacity:0}.ipad-simple-device.tapped i{animation:tapSimple .6s ease-out}@keyframes tapSimple{0%{opacity:1;transform:translate(-50%,-50%) scale(.2)}100%{opacity:0;transform:translate(-50%,-50%) scale(4)}}
.ipad-simple-stage{position:relative;min-height:500px;border-radius:18px;background:#eef5fb;border:1px solid #33546f;padding:38px 28px;display:grid;grid-template-columns:1.2fr auto 1fr auto 1fr auto 1.2fr;gap:10px;align-items:center}.touch-grid-simple,.chip-simple,.pixel-grid-simple{border:2px solid #9fb9cc;border-radius:16px;background:#fff;min-height:150px;display:grid;place-items:center;text-align:center;font-weight:900;color:#173754;position:relative}.touch-grid-simple i,.pixel-grid-simple i{position:absolute;width:10px;height:10px;border-radius:50%;background:#57bdf4;opacity:.2}.touch-grid-simple i:nth-child(2){left:28%;top:35%}.touch-grid-simple i:nth-child(3){left:55%;top:52%}.touch-grid-simple i:nth-child(4){left:70%;top:25%}.touch-grid-simple i:nth-child(5){left:42%;top:72%}.chip-simple b{font-size:2.2rem}.chip-simple span{display:block}.signal-arrow{font-size:2rem;color:#157bc4;opacity:.25}.pixel-grid-simple{background:linear-gradient(135deg,#cfe9ff,#eee1ff)}.pixel-grid-simple i:nth-child(2){left:20%;top:25%;background:#ff5b5b}.pixel-grid-simple i:nth-child(3){left:45%;top:25%;background:#51c769}.pixel-grid-simple i:nth-child(4){left:70%;top:25%;background:#4a85ff}.pixel-grid-simple i:nth-child(5){left:32%;top:62%;background:#ff5b5b}.pixel-grid-simple i:nth-child(6){left:58%;top:62%;background:#51c769}.pixel-grid-simple i:nth-child(7){left:78%;top:62%;background:#4a85ff}.ipad-simple-stage.active1 .touch-grid-simple,.ipad-simple-stage.active2 .cpu,.ipad-simple-stage.active3 .mem,.ipad-simple-stage.active4 .pixel-grid-simple{outline:4px solid #21b9ff;transform:translateY(-5px)}.ipad-simple-stage.active2 .s1,.ipad-simple-stage.active3 .s1,.ipad-simple-stage.active3 .s2,.ipad-simple-stage.active4 .signal-arrow{opacity:1;animation:signalPulse .45s ease}@keyframes signalPulse{50%{transform:scale(1.35);color:#03a6ff}}

/* rocket */
.rocket-simple-ignite{display:block;width:100%;background:#f3b52d;border:0;border-radius:14px;padding:15px 10px;font:inherit;font-weight:950;cursor:pointer;box-shadow:0 5px 0 #b77d11}.rocket-simple-ignite:active,.rocket-simple-ignite.firing{transform:translateY(4px);box-shadow:0 1px 0 #b77d11}.rocket-simple-stage{position:relative;min-height:500px;border-radius:18px;background:linear-gradient(#07152f,#173d72);border:1px solid #33546f;overflow:hidden}.rocket-tank{position:absolute;top:60px;width:90px;height:150px;border-radius:22px;padding-top:62px;text-align:center;font-weight:950;color:#fff}.rocket-tank.fuel{left:8%;background:#cf812d}.rocket-tank.oxygen{left:28%;background:#2a88d0}.rocket-pipe{position:absolute;top:205px;width:180px;height:7px;border-radius:999px}.fuel-p{left:14%;background:#ffad38;transform:rotate(14deg)}.oxy-p{left:33%;background:#5bcaff;transform:rotate(4deg)}.rocket-pipe i{position:absolute;width:10px;height:10px;border-radius:50%;background:#fff;opacity:0;top:-2px}.chamber-simple{position:absolute;left:57%;top:165px;width:125px;height:115px;border:8px solid #88939b;border-radius:16px;background:#303c45;color:#fff;text-align:center;padding-top:10px;font-size:.65rem;font-weight:900}.rocket-fire{position:absolute;left:50%;bottom:8px;width:85px;height:70px;transform:translateX(-50%) scale(.2);border-radius:50%;background:radial-gradient(circle,#fffbd0 0 12%,#ffd329 26%,#ff7518 54%,rgba(255,55,0,.25) 70%,transparent 74%);opacity:0}.nozzle-simple{position:absolute;left:59%;top:280px;width:90px;height:90px;background:#6e7880;clip-path:polygon(25% 0,75% 0,100% 100%,0 100%)}.rocket-exhaust-simple{position:absolute;left:59%;top:350px;width:90px;text-align:center;color:#ffd275;font-size:2.2rem}.rocket-exhaust-simple i{display:inline-block;font-style:normal;opacity:.2}.rocket-body-simple{position:absolute;right:8%;top:95px;font-size:7.5rem;transition:.25s}.rocket-thrust-arrow{position:absolute;right:13%;top:38px;color:#fff;font-size:2.2rem;font-weight:950;text-align:center;opacity:.3}.rocket-thrust-arrow span{display:block;font-size:.72rem}.rocket-simple-stage.firing .rocket-pipe i{opacity:1;animation:rocketParticle .7s linear infinite}.rocket-simple-stage.firing .rocket-pipe i:nth-child(2){animation-delay:.2s}.rocket-simple-stage.firing .rocket-pipe i:nth-child(3){animation-delay:.4s}.rocket-simple-stage.firing .rocket-fire{opacity:1;animation:rocketBurn .6s ease-in-out infinite}.rocket-simple-stage.firing .rocket-exhaust-simple i{opacity:1;animation:rocketExhaust .55s linear infinite}.rocket-simple-stage.firing .rocket-body-simple{transform:translateY(-28px)}.rocket-simple-stage.firing .rocket-thrust-arrow{opacity:1;animation:rocketLift .7s ease-in-out infinite alternate}@keyframes rocketParticle{0%{left:0}100%{left:92%}}@keyframes rocketBurn{50%{transform:translateX(-50%) scale(1.15)}}@keyframes rocketExhaust{to{transform:translateY(28px);opacity:.2}}@keyframes rocketLift{to{transform:translateY(-10px)}}

@media(max-width:1080px){.flagship-grid{grid-template-columns:180px 1fr}.simple-steps-panel{grid-column:1/-1;grid-template-columns:repeat(4,1fr)}.simple-what{grid-column:1/-1}}
@media(max-width:760px){.flagship-simple{padding:16px}.flagship-head{flex-direction:column}.flagship-grid{grid-template-columns:1fr}.simple-steps-panel{grid-column:auto;grid-template-columns:1fr}.air-simple-stage,.solar-simple-stage,.ipad-simple-stage,.rocket-simple-stage{min-height:420px}.ipad-simple-stage{grid-template-columns:1fr;gap:8px}.signal-arrow{transform:rotate(90deg)}.rocket-tank{transform:scale(.85);transform-origin:top left}.chamber-simple{left:50%}.nozzle-simple{left:53%}.rocket-exhaust-simple{left:53%}}

/* v5.6 rewards, engineer challenges, and next-mystery flow */
.reward-zone{margin:38px 0;display:grid;gap:18px}
.reward-card{display:grid;grid-template-columns:74px 1fr;gap:16px;align-items:center;background:linear-gradient(135deg,#0b2a45,#133f61);color:#fff;border-radius:22px;padding:20px;border:1px solid #2c6386;box-shadow:0 14px 34px rgba(8,28,47,.18)}
.reward-card h2{color:#fff;margin:.1rem 0 .35rem}.reward-card p{color:#c9dbe8}.reward-icon{width:64px;height:64px;border-radius:50%;display:grid;place-items:center;background:#f5c43c;font-size:2rem;box-shadow:0 0 0 6px rgba(245,196,60,.15)}
.mystery-progress{margin-top:10px;display:flex;justify-content:space-between;gap:10px;background:#0b2238;border:1px solid #315f7c;border-radius:12px;padding:10px 12px}.mystery-progress span{color:#b8cddd}.mystery-progress strong{color:#fff}
.engineer-challenge{background:#fff;border:2px solid #d6e6f2;border-radius:22px;padding:20px;box-shadow:0 12px 30px rgba(18,52,78,.08)}.engineer-challenge h3{margin:.2rem 0 14px;color:#10253a}
.challenge-options{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.challenge-option{border:2px solid #b9d1e2;background:#f7fbfe;color:#12334b;border-radius:14px;padding:14px 10px;font:inherit;font-weight:850;cursor:pointer;min-height:72px}.challenge-option:hover{transform:translateY(-2px)}.challenge-option.correct{border-color:#38b35d;background:#ebfaef}.challenge-option.wrong{border-color:#e05b5b;background:#fff0f0}.challenge-feedback{margin-top:12px;border-radius:12px;background:#edf6fc;padding:11px 12px;color:#2f4b60;font-weight:750}.challenge-feedback.success{background:#eaf8ee;color:#236f38}
.next-mysteries{background:#0b243a;color:#fff;border-radius:20px;padding:18px}.next-mystery-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}.next-mystery-card{display:block;background:#113754;color:#fff;text-decoration:none;border:1px solid #2d6283;border-radius:14px;padding:14px;font-weight:900}.next-mystery-card:hover{background:#15527b;transform:translateY(-2px)}
.home-mystery-strip{margin:24px auto 34px;max-width:1180px;background:linear-gradient(135deg,#0a2943,#104b70);color:#fff;border-radius:22px;padding:20px 24px;display:flex;justify-content:space-between;gap:22px;align-items:center}.home-mystery-strip h2{color:#fff;margin:.15rem 0 .35rem}.home-mystery-strip p{color:#c6dae8}.badge-row{display:flex;gap:9px;flex-wrap:wrap;justify-content:flex-end}.badge-row span{width:48px;height:48px;border-radius:50%;display:grid;place-items:center;background:#173c58;filter:grayscale(1);opacity:.45;font-size:1.45rem;border:2px solid #315d79}.badge-row span.unlocked{filter:none;opacity:1;background:#f4c33c;border-color:#ffdf71}
@media(max-width:760px){.challenge-options{grid-template-columns:1fr}.next-mystery-grid{grid-template-columns:1fr}.reward-card{grid-template-columns:1fr}.home-mystery-strip{margin:20px 14px 28px;flex-direction:column;align-items:flex-start}.badge-row{justify-content:flex-start}}

/* v5.7 electric vehicle */
.ev56{background:#081c31;color:#fff;border-radius:26px;padding:24px;margin:34px 0}.ev56-grid{display:grid;grid-template-columns:190px minmax(430px,1fr) 300px;gap:14px;margin-top:18px}.ev56-controls,.ev56-steps{background:#0d2c46;border:1px solid #28516e;border-radius:18px;padding:16px}.ev56-presets{display:grid;grid-template-columns:repeat(3,1fr);gap:5px}.ev56-presets button{background:#153a56;color:#fff;border:1px solid #35617f;border-radius:9px;padding:8px 3px;font-weight:900}.ev56-presets small{display:block;font-size:.55rem}.ev56-pedal{width:100px;height:170px;display:block;margin:12px auto;background:transparent;border:0}.ev56-pedal span{display:grid;place-items:center;width:70px;height:130px;margin:auto;background:#303c47;border:3px solid #929ca5;border-radius:14px;font-size:3rem;box-shadow:0 12px 0 #060a0e;transition:.12s}.ev56-pedal.pressed span{transform:perspective(220px) rotateX(19deg) translateY(9px);box-shadow:0 3px 0 #060a0e}.ev56-meter{background:#103653;border-radius:12px;padding:10px}.ev56-meter span,.ev56-meter strong{display:block}.ev56-meter>div{height:10px;background:#1c455f;border-radius:999px;overflow:hidden;margin-top:7px}.ev56-meter i{display:block;height:100%;width:0;background:#53d84d}.ev56-stage{position:relative;min-height:500px;border-radius:18px;background:radial-gradient(circle,#29435a,#08141f 72%);overflow:hidden}.ev56-battery{position:absolute;left:12%;bottom:18%;width:48%;height:105px;border:5px solid #687c8b;border-radius:13px;background:#243847;padding:9px;font-weight:950}.ev56-battery>div{display:grid;grid-template-columns:repeat(5,1fr);gap:4px;margin-top:10px}.ev56-battery i{height:48px;background:#39b95c;border-radius:5px}.ev56-inverter{position:absolute;left:43%;top:24%;width:120px;height:78px;border:5px solid #8295a3;border-radius:12px;background:#d9e0e4;color:#243746;display:grid;place-items:center;font-weight:950}.ev56-inverter small{font-size:.55rem}.ev56-wire{position:absolute;height:8px;background:#e6b92f;border-radius:999px}.w1{left:35%;bottom:39%;width:18%;transform:rotate(-43deg)}.w2{left:57%;top:35%;width:18%;transform:rotate(16deg)}.ev56-wire b{position:absolute;width:11px;height:11px;border-radius:50%;background:#fff24a;top:-2px;opacity:0}.ev56-motor{position:absolute;right:15%;top:34%;text-align:center}.ev56-motor>div{width:120px;height:120px;border:18px solid #5e8098;border-radius:50%;background:linear-gradient(90deg,#df5151 50%,#397fd3 50%);display:grid;place-items:center;font-weight:950}.ev56-motor span,.ev56-gear span{display:block;font-size:.7rem;font-weight:950}.ev56-gear{position:absolute;right:10%;bottom:19%;font-size:3.7rem;text-align:center}.ev56-axle{position:absolute;left:25%;right:9%;bottom:11%;height:10px;background:#77848e}.ev56-wheel{position:absolute;bottom:4%;width:78px;height:78px;border:15px solid #1d252b;border-radius:50%;background:#77848e}.ev56-wheel.left{left:15%}.ev56-wheel.right{right:5%}.ev56-stage.running .ev56-wire b{opacity:1;animation:evCharge .7s linear infinite}.ev56-stage.running .ev56-wire b:nth-child(2){animation-delay:.2s}.ev56-stage.running .ev56-wire b:nth-child(3){animation-delay:.4s}.ev56-stage.running .ev56-motor>div,.ev56-stage.running .ev56-gear,.ev56-stage.running .ev56-wheel{animation:evSpin .8s linear infinite}@keyframes evCharge{from{left:0}to{left:92%}}@keyframes evSpin{to{transform:rotate(360deg)}}.ev56-steps{display:grid;gap:8px}.ev56-steps .simple-step{display:grid;grid-template-columns:38px 1fr;gap:8px;background:#f8fbff;color:#10233a;border-radius:13px;padding:10px;opacity:.75}.ev56-steps .simple-step b{width:36px;height:36px;border-radius:50%;display:grid;place-items:center;background:#1887ef;color:#fff}.ev56-steps .simple-step strong,.ev56-steps .simple-step small{display:block}.ev56-steps .simple-step small{font-size:.7rem}.ev56-steps .simple-step.active{opacity:1;outline:3px solid #12c6ff}.ev56-steps .simple-what{background:#e9f5ff;color:#10243b;border-radius:13px;padding:12px}.ev56-steps .simple-what p{font-size:.78rem}@media(max-width:1050px){.ev56-grid{grid-template-columns:180px 1fr}.ev56-steps{grid-column:1/-1}}@media(max-width:760px){.ev56-grid{grid-template-columns:1fr}.ev56-stage{min-height:420px}.ev56-steps{grid-column:auto}}


/* v5.8.35: Simplify only the lab area, not the lesson below it.
   Detailed reading, engineering context, quizzes, completion and next-topic
   sections use their original visible styles. Keep the extra path bar hidden. */
body[data-topic-page] .ss-learning-path{display:none!important}
body[data-topic-page] .article-shell{max-width:1120px;padding-bottom:40px}
body[data-topic-page] .article-hero{padding-bottom:12px;margin-bottom:18px}
body[data-topic-page] .article-hero .meta{display:none}
body[data-topic-page] .article-back{margin-bottom:14px}


/* v5.8.51 car race reward — inline below the quiz */
.race-unlock-card{margin:18px 0 30px;padding:24px 26px;border:1px solid #d7c86c;border-radius:20px;background:#fff9dc;display:grid;grid-template-columns:auto minmax(0,1fr) auto;align-items:center;gap:18px;color:var(--text)}
.race-unlock-card[hidden]{display:none!important}
.race-unlock-card .race-unlock-icon{font-size:2.6rem;line-height:1}
.race-unlock-card .eyebrow{margin:0 0 5px!important}
.race-unlock-card h2{margin:0 0 6px!important;font-size:clamp(1.35rem,3vw,1.85rem);line-height:1.15}
.race-unlock-card p:not(.eyebrow){margin:0!important;color:var(--muted);font-size:.95rem!important}
.race-unlock-card .button{min-height:48px;display:inline-flex;align-items:center;justify-content:center;white-space:nowrap}
.race-unlocked-now{animation:race-reveal .35s ease both}
@keyframes race-reveal{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
@media(max-width:700px){.race-unlock-card{grid-template-columns:auto 1fr;padding:20px}.race-unlock-card .button{grid-column:1/-1;width:100%}}
@media(prefers-reduced-motion:reduce){.race-unlocked-now{animation:none}}

/* v5.8.60 lesson game unlocks */
.game-unlock-card .race-unlock-icon{font-size:2.8rem}.game-unlock-card a.button{text-decoration:none}


/* v5.8.70 game surprise teaser */
.game-surprise-note{
  display:flex;
  align-items:center;
  gap:10px;
  width:max-content;
  max-width:100%;
  margin:4px 0 20px;
  padding:10px 14px;
  border:1px solid #ead78a;
  border-radius:12px;
  background:#fff8dc;
  color:#4f4417;
  font-size:.9rem;
}
.game-surprise-note span{font-size:1.15rem;line-height:1}
.game-surprise-note strong{font-weight:850}
@media(max-width:650px){
  .game-surprise-note{width:100%;font-size:.84rem;line-height:1.4}
}