.lesson-motion{margin:22px 0 28px;border:1px solid #b8cec9;border-radius:16px;overflow:hidden;background:#e8f0e8;box-shadow:0 5px 0 #18313b08}.motion-head{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 16px;border-bottom:1px solid #c8d8ce;background:#f4f6ed}.motion-head span{font:700 11px system-ui,sans-serif;letter-spacing:.07em;color:#356272}.motion-head button,.motion-options button,.motion-global{font:600 12px system-ui,sans-serif;min-height:44px;padding:8px 12px;border-radius:8px}.motion-head button{background:#fffaf0}.motion-stage{position:relative;background:linear-gradient(#daeaf1,#eef1e1)}.motion-stage svg{display:block;width:100%;height:auto;aspect-ratio:600/280}.motion-stage .spin,.motion-stage .swirl,.motion-stage .gust-arrow,.motion-stage .shed,.motion-stage .lift-bob{transform-box:fill-box;transform-origin:center}.motion-stage .cloud{fill:#fffcf0;opacity:.8}.motion-stage .wing{fill:#fff5df;stroke:#244c62;stroke-width:3;stroke-linejoin:round}.motion-stage .blue-body{fill:#2d749b;stroke:#244c62;stroke-width:3}.motion-stage .flowline{fill:none;stroke:#3a819e;stroke-width:3;stroke-linecap:round}.motion-stage .moving{stroke-dasharray:5 17;animation:air-passing 3s linear infinite}.motion-stage .warm{stroke:#c76533}.motion-stage .force{stroke:#c65d30;stroke-width:6;fill:none;stroke-linecap:round;stroke-linejoin:round}.motion-stage .muted{stroke:#92b6bb}.motion-stage text{font:650 20px system-ui,sans-serif;fill:#244c62}.motion-stage .small-text{font-size:17px}.motion-stage .number{font-size:20px;font-weight:750}.motion-stage .lift-bob{animation:lift-bob 3s ease-in-out infinite}.motion-stage .spin{animation:prop-spin 4s linear infinite}.motion-stage .pulse{animation:glow 3s ease-in-out infinite}.motion-stage .shed{animation:shed-vortex 8s ease-in-out infinite}.motion-stage .initial-flow{animation:initial-flow 8s linear infinite}.motion-stage .settled-flow{animation:settled-flow 8s linear infinite}.motion-stage .slow-flow{animation-duration:7s}.motion-stage .fast-flow{animation-duration:2.7s}.motion-stage .swirl{animation:prop-spin 6s linear infinite}.motion-options{display:flex;flex-wrap:wrap;gap:6px;padding:12px 14px 0}.motion-options button[aria-pressed=true]{background:#244c62;color:#fff7e8;border-color:#244c62}.motion-key{display:flex;flex-wrap:wrap;gap:7px;padding:12px 16px 0}.motion-key span{font:600 12px/1.5 system-ui,sans-serif;padding:3px 8px;border-radius:5px;background:#fffaf0;color:#244c62;border:1px solid #cad8cc}.lesson-motion figcaption{font:14px/1.6 system-ui,sans-serif;color:#3b5962;padding:12px 16px 16px}.motion-global{margin:12px 0 0}.lesson-motion[data-paused=true] svg *,.lesson-motion.is-offscreen svg *,.lesson-motion.page-hidden svg *{animation-play-state:paused!important}.motion-stage [data-scene]{display:none}.lesson-motion[data-state=attached] [data-scene=attached],.lesson-motion[data-state=stalled] [data-scene=stalled],.lesson-motion[data-state=short] [data-scene=short],.lesson-motion[data-state=long] [data-scene=long],.lesson-motion[data-state=flaps] [data-scene=flaps],.lesson-motion[data-state=spoilers] [data-scene=spoilers],.lesson-motion[data-state=wake] [data-scene=wake]{display:inline}.gust-arrow{transform:rotate(0deg)}.lesson-motion[data-state=gust] .gust-arrow{transform:rotate(-10deg)}.gust-arc{opacity:0}.lesson-motion[data-state=gust] .gust-arc{opacity:1}.gust-fixed{opacity:1}.lesson-motion[data-state=gust] .gust-fixed{opacity:0}
@keyframes air-passing{to{stroke-dashoffset:-88}}@keyframes lift-bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-7px)}}@keyframes prop-spin{to{transform:rotate(360deg)}}@keyframes glow{0%,100%{opacity:.5}50%{opacity:1}}@keyframes shed-vortex{0%,20%{opacity:0;transform:translate(0,0) scale(.2)}35%{opacity:1;transform:translate(0,0) scale(1)}80%,100%{opacity:0;transform:translate(140px,35px) scale(1.5)}}@keyframes initial-flow{0%,25%{opacity:1}38%,100%{opacity:0}}@keyframes settled-flow{0%,25%{opacity:.15}42%,100%{opacity:1}}@media(max-width:480px){.motion-head{padding:8px 12px}.motion-head span{font-size:9px}.motion-stage svg{aspect-ratio:600/300}.motion-key{padding:10px 12px 0;gap:5px}.motion-key span{font-size:11px}.lesson-motion figcaption{font-size:13px;padding:10px 12px 14px}.motion-options{padding:10px 12px 0}.motion-options button{font-size:11px;flex:1}.lesson-motion{margin-inline:-5px}}@media(prefers-reduced-motion:reduce){.lesson-motion:not([data-motion-opt-in=true]) svg *{animation:none!important}.lesson-motion:not([data-motion-opt-in=true]) .initial-flow,.lesson-motion:not([data-motion-opt-in=true]) .shed{opacity:0}.lesson-motion:not([data-motion-opt-in=true]) .settled-flow{opacity:1}}
/* Cause-and-effect guides: plain observation first; technical detail on request. */
.motion-guide{padding:14px 16px 6px;background:#f4f6ed}.reading .motion-notice{font:650 17px/1.5 system-ui,sans-serif;margin:0;color:#183d4b}.reading .motion-hint{font:13px/1.55 system-ui,sans-serif;margin:6px 0 0;color:#4a6570}.motion-options{background:#f4f6ed;padding-bottom:12px}.motion-options button{border-color:#a3bab7;background:#fffaf0}.lesson-motion figcaption{padding:0 16px 12px}.lesson-motion .motion-explainer{margin:0;padding:10px 0 0;border-top:1px solid #c8d8ce}.motion-explainer summary{font:600 12px/1.5 system-ui,sans-serif;min-height:36px;display:list-item}.reading .motion-explainer p{font:13px/1.65 system-ui,sans-serif;margin:10px 0}.motion-key{padding:0}.motion-step-controls{padding:12px 16px;display:flex;gap:10px;align-items:center;justify-content:space-between;background:#f4f6ed}.motion-step-count{font:600 12px system-ui,sans-serif;color:#4a6570;white-space:nowrap}.motion-next{font:600 12px system-ui,sans-serif;background:#244c62;color:#fff7e8;min-height:44px;padding:8px 12px}.stage-highlight{display:none;stroke:#c56332;stroke-width:5;fill:none;stroke-dasharray:9 5}.lesson-motion[data-concept=jet][data-phase="0"] [data-step="0"],.lesson-motion[data-concept=jet][data-phase="1"] [data-step="1"],.lesson-motion[data-concept=jet][data-phase="2"] [data-step="2"],.lesson-motion[data-concept=jet][data-phase="3"] [data-step="3"],.lesson-motion[data-concept=jet][data-phase="4"] [data-step="4"]{display:inline}.lesson-motion[data-concept=start] .initial-flow,.lesson-motion[data-concept=start] .settled-flow{animation:none}.lesson-motion[data-concept=start][data-phase="0"] .initial-flow{opacity:1}.lesson-motion[data-concept=start][data-phase="0"] .settled-flow{opacity:0}.lesson-motion[data-concept=start][data-phase="0"] .shed{display:none}.lesson-motion[data-concept=start][data-phase="1"] .initial-flow{opacity:.15}.lesson-motion[data-concept=start][data-phase="1"] .settled-flow{opacity:.6}.lesson-motion[data-concept=start][data-phase="1"] .shed{animation:guided-shed 4s ease-out infinite}.lesson-motion[data-concept=start][data-phase="2"] .initial-flow,.lesson-motion[data-concept=start][data-phase="2"] .shed{display:none}.lesson-motion[data-concept=start][data-phase="2"] .settled-flow{opacity:1}.lesson-motion[data-concept=fan][data-state=bypass] .core-flow,.lesson-motion[data-concept=fan][data-state=core] .bypass-flow{opacity:.18}.lesson-motion[data-concept=ram][data-state=ramjet] .scramjet-view,.lesson-motion[data-concept=ram][data-state=scramjet] .ramjet-view{opacity:.22}.lesson-motion[data-concept=prop][data-state=air] .spin circle{opacity:.5}.lesson-motion[data-concept=prop][data-state=tip] .flowline{opacity:.2}@keyframes guided-shed{0%{opacity:1;transform:translate(0,0) scale(.7)}75%,100%{opacity:0;transform:translate(120px,30px) scale(1.4)}}@media(max-width:480px){.motion-guide{padding:12px 12px 5px}.reading .motion-notice{font-size:14px}.reading .motion-hint{font-size:12px}.motion-options{padding-bottom:10px}.motion-step-controls{padding:10px 12px;gap:8px}.motion-next{font-size:11px}.lesson-motion figcaption{padding:0 12px 10px}}@media(prefers-reduced-motion:reduce){.lesson-motion[data-concept=start]:not([data-motion-opt-in=true])[data-phase="1"] .shed{animation:none!important;opacity:1;transform:translate(65px,15px)}}