/* Visual lessons share the site's quiet blue and charcoal palette. */
.academy-hero{padding:78px 0 66px;overflow:hidden;background:radial-gradient(ellipse at 78% 40%,#18334a66,transparent 58%)}
.academy-hero>.wrap{display:grid;grid-template-columns:.85fr 1.15fr;gap:64px;align-items:center}
.academy-hero h1{font-size:clamp(2.8rem,4.6vw,4.7rem);line-height:1.3;letter-spacing:-.055em;font-weight:500;margin:20px 0}
.academy-hero h1 em{font-style:normal;color:#a0deff}.academy-hero .lead{font-size:1.05rem;margin:20px 0 29px}.academy-hero .btn{margin-top:31px;gap:26px}
.academy-counts{display:flex;gap:22px;flex-wrap:wrap;font-size:.75rem;color:#88a3bb}.academy-counts b{font:400 1.4rem ui-monospace,monospace;color:#d7edfd;margin-right:5px}
.academy-hero-visual{display:block;border:1px solid #38516a;background:#0c1826;position:relative;box-shadow:0 26px 85px #0005}
.academy-hero-visual .optical-scene{aspect-ratio:1.45}.academy-hero-visual .optical-scene img{object-fit:cover;object-position:32% 50%}.academy-hero-visual .sound-overlay{display:none}
.academy-hero-visual .optical-scene:after{content:"";position:absolute;left:18%;top:32%;width:20%;aspect-ratio:1;background:radial-gradient(ellipse,#fff3a2 0%,#ff643d 11%,#ffa742 22%,#58d6a37a 42%,#3593dc56 60%,transparent 72%);border-radius:50%}
.hero-visual-caption{position:relative;padding:25px 28px 27px}.hero-visual-caption .mono{display:block;font-size:.65rem;letter-spacing:.09em;color:#7da3c2;margin-bottom:12px}.hero-visual-caption strong{font-size:1.22rem;font-weight:500;color:#e0f1ff}.visual-play{position:absolute;right:27px;top:32px;font-size:1.7rem;color:#8bd8ff}.academy-hero-visual:hover{border-color:#8bd8ff}
.illustrated-card{padding:0!important;overflow:hidden;background:#0c1826}.lesson-art{height:auto;aspect-ratio:2.12;background:#0d1d2d;border-bottom:1px solid #2a4259;overflow:hidden}.lesson-art .academy-svg{width:100%;height:100%;object-fit:cover;transition:transform .4s}.lesson-art .lesson-photo{height:100%}.illustrated-card:hover .academy-svg,.illustrated-card:hover .lesson-photo img{transform:scale(1.035)}
.lesson-card-copy{padding:24px;display:flex;flex-direction:column;flex:1}.lesson-card-copy h3{margin:19px 0 13px;line-height:1.55;font-size:1.22rem}.lesson-card-copy p{font-size:.87rem;margin-bottom:27px}.lesson-open{font-size:.8rem}
.lesson-photo{position:relative;overflow:hidden}.lesson-photo img{width:100%;height:100%;object-fit:cover;transition:transform .4s}.lesson-photo:after{content:"";position:absolute;inset:0;background:linear-gradient(0deg,#06101dc9,transparent 50%)}
.photo-corner{position:absolute;z-index:1;bottom:13px;left:19px;font:.56rem ui-monospace,monospace;letter-spacing:.12em;color:#d0e5f6}
.cover-target{position:absolute;width:21%;aspect-ratio:1;left:15%;top:26%;border-radius:50%;background:radial-gradient(ellipse,#fff6a0 0%,#ff7448 14%,#f3bc46 24%,#59dca680 42%,#3da7e870 62%,transparent 73%)}
.cover-map .cover-target{width:37%;left:7%;top:12%}.cover-map .cover-target:after{content:"+";position:absolute;inset:0;display:grid;place-items:center;color:white;font-size:2rem;font-weight:200}.cover-record .cover-target{background:none;width:44%;left:12%;top:10%;border-radius:0;border:1px solid #bdeaff;box-shadow:0 0 0 100px #07162545}.cover-record .photo-corner{color:#b2e5ff}
.reading-header{max-width:960px;padding-bottom:32px}.reading-header h1{font-size:clamp(2rem,3.8vw,3.25rem)}.reading-header .key-thought{background:none;border:0;border-left:2px solid #8bd8ff;margin-top:23px;padding:6px 0 6px 20px;gap:24px}.reading-header .key-thought p{font-size:.96rem;color:#b5cddd}.reading-header .key-thought span{color:#79a6c7}
.lesson-exhibit{border:1px solid #34516b;background:#0a1725;position:relative;scroll-margin-top:105px}
.exhibit-heading{padding:25px 29px;display:flex;justify-content:space-between;align-items:center;gap:24px;border-bottom:1px solid #2d455b}.exhibit-heading .mono{font-size:.62rem;letter-spacing:.1em;color:#79a0bf}.exhibit-heading h2{font-size:1.4rem;line-height:1.5;margin-top:12px;letter-spacing:-.02em}.exhibit-hint{color:#a4d3ee;font-size:.75rem;border:1px solid #355570;padding:7px 11px;white-space:nowrap}
.exhibit-grid{display:grid;grid-template-columns:minmax(0,1fr) 280px;align-items:stretch}.exhibit-picture{background:#0b1928;display:flex;flex-direction:column;justify-content:center;min-width:0}.exhibit-controls{padding:30px 26px;background:#0c1c2c;border-left:1px solid #2d455b;min-width:0}.exhibit-caption{font-size:.72rem!important;color:#87a3bb!important;line-height:1.8!important;margin:0!important;padding:17px 27px;border-top:1px solid #2d455b}.visual-noscript{padding:14px 26px;font-size:.8rem;color:#c3daed}
.academy-svg{display:block;width:100%;height:auto;overflow:hidden}.control-prompt{font-size:.83rem;color:#b6d0e5;margin:0 0 16px;line-height:1.8}.visual-options{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:26px}.visual-options button{padding:9px 12px;min-height:40px;background:#0c1b2b;border:1px solid #3d5972;color:#9bb8ce;border-radius:3px;font-size:.78rem;line-height:1.5;cursor:pointer}.visual-options button:hover{border-color:#8bd8ff}.visual-options button[aria-pressed=true]{background:#a2dfff;border-color:#a2dfff;color:#071725;font-weight:550}
.visual-insight{padding-top:22px;border-top:1px solid #2d455b}.visual-insight .mono{font-size:.64rem;color:#6ba1c5}.visual-insight h3{font-size:1.13rem;line-height:1.65;color:#e0effb;margin:12px 0}.visual-insight p{font-size:.85rem;line-height:1.9;color:#a4bdcf;margin:0}.control-footnote{font-size:.7rem;line-height:1.9;color:#7896ae;margin-top:22px}.visual-control{margin:23px 0}.visual-control label{font-size:.79rem;line-height:1.75;color:#a8c3d9;display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap}.visual-control output{font-family:ui-monospace,monospace;color:#cff0ff}.visual-control input{display:block;width:100%;margin:13px 0 9px;accent-color:#9adeff;cursor:pointer}.visual-control .range-limits{font-size:.67rem}.visual-answer{border-top:1px solid #2c475f;padding-top:20px;margin-top:25px}.visual-answer span{display:block;font-size:.75rem;color:#90b0c9}.visual-answer strong{display:block;font:400 2rem/1.6 ui-monospace,monospace;color:#b1e8ff;margin-top:7px}.visual-feedback{font-size:.84rem;line-height:1.8;color:#bdd5e8;margin-top:22px}
.optical-scene{width:100%;aspect-ratio:1672/941;position:relative;overflow:hidden;background:#172b3e}.optical-scene picture,.optical-scene img{width:100%;height:100%;display:block;object-fit:cover}.sound-overlay{position:absolute;inset:0}.scene-heat,.scene-reticle{position:absolute;left:var(--x);top:var(--y);transform:translate(-50%,-50%)}.scene-heat{width:18%;aspect-ratio:1;border-radius:50%;background:radial-gradient(ellipse,#fff6b1 0%,#ff6544 15%,#ffa638 28%,#8ddd6cbd 42%,#3fc4c391 53%,#3d80e875 62%,transparent 74%);opacity:.9;transition:width .4s}.scene-reticle{width:6%;aspect-ratio:1;z-index:1}.scene-reticle:before,.scene-reticle:after{content:"";position:absolute;background:#fff;box-shadow:0 0 5px #003965}.scene-reticle:before{width:100%;height:1px;top:50%}.scene-reticle:after{width:1px;height:100%;left:50%}.scene-reticle i{position:absolute;inset:32%;border:1px solid white;background:#ffd57650}.scene-label{position:absolute;left:35%;top:30%;font-size:.75rem;color:white;padding:5px 9px;background:#081827cb;border:1px solid #d5e6f18c}.scene-label:before{content:"";width:32px;height:1px;background:#d5e6f1;position:absolute;right:100%;top:100%;transform-origin:right;transform:rotate(-25deg)}.scene-stamp{position:absolute;bottom:12px;right:13px;color:#d8e8f3;background:#091726c4;font-size:.62rem;letter-spacing:.02em;padding:5px 9px}
[data-scene-mode=optical] .sound-overlay{display:none}[data-scene-mode=map] .scene-heat{width:41%;opacity:.65}[data-scene-mode=map] .scene-reticle{display:none}[data-scene-mode=map] .scene-label{display:none}
.visual-key{padding:5px 0;margin:0;list-style:none}.visual-key li{display:flex;gap:15px;padding:20px 0;border-bottom:1px solid #2a435a}.visual-key li:last-child{border:0}.visual-key b{font:400 .73rem/2 ui-monospace,monospace;color:#79b7dc}.visual-key strong{font-size:1rem;color:#cce6f8;font-weight:500}.visual-key p{font-size:.8rem;line-height:1.85;color:#8caec7;margin:9px 0 0}
.level-pair{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px;padding:28px}.level-panel{min-width:0}.level-panel>.mono{display:block;font-size:.73rem;letter-spacing:.04em;color:#a0c0d9;margin:3px 0 18px}.level-field{aspect-ratio:1;border:1px solid #304b65;position:relative;background:linear-gradient(#27466040 1px,transparent 1px),linear-gradient(90deg,#27466040 1px,transparent 1px);background-size:25% 25%}.level-spot{position:absolute;inset:5%;background:radial-gradient(ellipse,#fff6a0 0%,#ff644f 12%,#ffa53a 27%,#59dca6b3 40%,#3da7e877 58%,transparent 72%)}.field-cross{position:absolute;inset:0;display:grid;place-items:center;color:#fff;font:300 2rem system-ui;text-shadow:0 0 5px #000}.level-scale{display:flex;gap:12px;align-items:center;margin-top:18px}.level-scale i{width:36px;height:7px;background:linear-gradient(90deg,#3598df,#53d39f,#efb448,#ff644f);flex-shrink:0}.level-scale span{font-size:.65rem;color:#8eacc4;line-height:1.6}.level-panel>p{font-size:.85rem;color:#c9e2f3;margin:13px 0 0}.arrival-strip{display:flex;align-items:center;position:relative;height:58px;margin-top:26px;font-size:.66rem;color:#94b2c9;gap:15px}.arrival-strip:before{content:"";height:1px;position:absolute;left:45px;right:45px;background:#476682}.arrival-strip span:last-child{margin-left:auto}.arrival-strip i,.arrival-strip b{display:block;width:3px;height:25px;background:#8bd8ff;z-index:1}.arrival-strip i{margin-left:20px}.arrival-strip b{background:#ffd28a;margin-left:50px;height:18px}
.field-guide{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));padding:14px 12px}.field-step{padding:21px 20px 26px;min-width:0}.field-step+.field-step{border-left:1px solid #2d455b}.field-step>.mono{font:.75rem ui-monospace,monospace;color:#557e9c}.field-step svg{display:block;width:100px;height:100px;margin:14px 0}.field-step h3{font-size:1.2rem;color:#d6eafa;margin-bottom:15px}.field-step strong{font-size:.86rem;font-weight:400;color:#a5d9f7}.field-step p{font-size:.8rem;line-height:1.95;color:#8facc3;margin:13px 0 0}
.reading-transition{padding:45px 0 23px;display:flex;justify-content:space-between;gap:20px;align-items:center;margin-top:25px}.reading-transition .mono{font-size:.68rem;letter-spacing:.08em;color:#7f9cb5}.reading-transition>span:last-child{font-size:.76rem;color:#7d94ab}.reading-section p{max-width:68ch}.reading-toc{top:108px}
.lesson-exhibit .lab{margin:0;border:0;grid-template-columns:minmax(0,1.35fr) minmax(280px,1fr);background:none}.lesson-exhibit .lab-visual{padding:24px}.lesson-exhibit .lab canvas{height:325px;width:100%;display:block}.lesson-exhibit .lab-heading{display:none}.lesson-exhibit .lab-visual>.lab-heading{display:flex;justify-content:flex-end;margin:0}.lesson-exhibit .lab-visual>.lab-heading h3{display:none}.lesson-exhibit .lab-controls{padding:30px 26px;background:#0c1c2c}.lesson-exhibit .lab-notes{font-size:.7rem;line-height:1.85;color:#85a3be}.lesson-exhibit .arrival-note{font-size:.87rem}.lesson-exhibit .equation{font-size:.76rem;overflow-wrap:anywhere}.lesson-exhibit .canvas-legend{font-size:.75rem}.lesson-exhibit .lab-results strong{font-size:1.5rem}.lesson-exhibit .lab-results small{font-size:.69rem}.lesson-exhibit .wavelength-lab{border:0;background:none;padding:25px 29px}.lesson-exhibit .wavelength-lab .lab-heading{display:none}.lesson-exhibit .wavelength-lab svg{margin:0 0 25px;max-height:310px}.lesson-exhibit .wave-controls{grid-template-columns:1fr 1fr}.lesson-exhibit .wave-results strong{font-size:1.75rem}.lesson-exhibit .control-row{min-width:0}.lesson-exhibit .control-label{flex-wrap:wrap}.lesson-exhibit .control-label output{white-space:normal;overflow-wrap:anywhere}
.lesson-exhibit *{min-width:0}.lesson-exhibit p,.lesson-exhibit strong,.lesson-exhibit h3,.lesson-exhibit output{overflow-wrap:break-word}.lesson-exhibit button:focus-visible,.lesson-exhibit input:focus-visible,.illustrated-card:focus-visible,.academy-hero-visual:focus-visible{outline:2px solid #d1efff;outline-offset:5px}
html:not(.js) .visual-options,html:not(.js) .visual-control input{display:none}
@media(min-width:801px) and (max-width:1100px){.academy-hero>.wrap{gap:35px}.academy-hero h1{font-size:3.5rem}.lesson-card-copy{padding:19px}.lesson-card-copy h3{font-size:1.1rem}.academy-counts{gap:13px}.exhibit-grid{grid-template-columns:minmax(0,1fr) 255px}.exhibit-controls{padding:23px 20px}.level-pair{gap:17px;padding:20px}}
@media(max-width:800px){.academy-hero{padding:48px 0 40px}.academy-hero>.wrap{grid-template-columns:1fr;gap:38px}.academy-hero h1{font-size:3.5rem}.academy-hero-visual .optical-scene{aspect-ratio:1672/941}.academy-hero-visual .optical-scene:after{left:15%;top:28%}.academy-hero .lead{margin:16px 0 24px}.academy-hero .btn{margin-top:25px}.hero-visual-caption{padding:21px 24px}.hero-visual-caption strong{font-size:1.1rem}.visual-play{top:25px}.illustrated-card{display:grid;grid-template-columns:minmax(0,.9fr) minmax(0,1.1fr)}.lesson-art{height:100%;aspect-ratio:auto;border:0;border-right:1px solid #2a4259;display:flex;align-items:center}.lesson-art .academy-svg{height:auto;min-height:100%;object-fit:cover}.lesson-art .lesson-photo{width:100%}.lesson-card-copy{padding:24px}.lesson-card-copy h3{font-size:1.2rem}.lesson-card-copy p{font-size:.85rem;margin-bottom:20px}.exhibit-grid{grid-template-columns:1fr}.exhibit-controls{border-left:0;border-top:1px solid #2d455b;padding:24px}.exhibit-picture .academy-svg{max-height:400px}.exhibit-heading{padding:22px 24px;flex-wrap:wrap;gap:14px}.exhibit-heading h2{font-size:1.3rem}.exhibit-hint{font-size:.68rem}.visual-options{margin-bottom:20px}.visual-options button{font-size:.85rem;padding:10px 14px}.visual-insight h3{font-size:1.15rem}.control-footnote{margin-top:18px}.exhibit-controls .visual-control{margin:21px 0}.visual-answer{margin-top:22px}.visual-key{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;padding:0}.visual-key li{display:block;border:0;padding:0}.visual-key b{display:block;margin-bottom:9px}.visual-key strong{font-size:.95rem}.visual-key p{font-size:.77rem}.level-pair{padding:26px;gap:24px}.field-guide{grid-template-columns:1fr 1fr;padding:10px}.field-step{padding:21px}.field-step+.field-step{border-left:0}.field-step:nth-child(even){border-left:1px solid #2d455b}.field-step:nth-child(n+3){border-top:1px solid #2d455b}.lesson-exhibit .lab{grid-template-columns:1fr}.lesson-exhibit .lab-controls{border-top:1px solid #2d455b;border-left:0}.lesson-exhibit .lab canvas{height:310px}.lesson-exhibit .lab-visual{padding:22px}.lesson-exhibit .lab-results strong{font-size:1.75rem}.lesson-exhibit .lab-visual>.lab-heading{margin-bottom:3px}.reading-transition{padding-top:28px;flex-wrap:wrap;gap:10px}.reading-transition>span:last-child{display:none}}
@media(max-width:520px){.academy-hero h1{font-size:2.9rem}.academy-hero .eyebrow{font-size:.66rem}.academy-hero>.wrap{gap:31px}.academy-counts{gap:17px}.academy-counts b{font-size:1.2rem}.academy-counts span{font-size:.7rem}.hero-visual-caption{padding:19px}.hero-visual-caption .mono{font-size:.58rem}.hero-visual-caption strong{font-size:1rem}.visual-play{right:18px;font-size:1.4rem}.illustrated-card{display:flex}.lesson-art{aspect-ratio:2.12;height:auto;display:block;border-right:0;border-bottom:1px solid #2a4259}.lesson-art .academy-svg{height:100%;min-height:0}.lesson-art .lesson-photo{height:100%}.lesson-card-copy{padding:24px}.lesson-card-copy h3{font-size:1.24rem}.learning-stage{padding-top:35px}.reading-header h1{font-size:2rem}.reading-header .key-thought{padding:4px 0 4px 17px}.reading-header .key-thought p{font-size:.88rem}.exhibit-heading{padding:20px}.exhibit-heading .mono{font-size:.55rem}.exhibit-heading h2{font-size:1.17rem;line-height:1.6;margin-top:10px}.exhibit-hint{border:0;padding:0;color:#80b2d1;white-space:normal}.exhibit-controls{padding:22px 20px}.exhibit-caption{padding:15px 20px;font-size:.65rem!important}.visual-options button{font-size:.77rem;padding:9px 10px}.visual-insight h3{font-size:1.1rem}.visual-insight p{font-size:.82rem}.visual-answer strong{font-size:1.7rem}.visual-control label{font-size:.8rem}.scene-label{font-size:.55rem;padding:3px 6px;top:23%}.scene-stamp{font-size:.5rem;right:8px;bottom:8px;padding:3px 6px}.scene-label:before{width:20px}.visual-key{grid-template-columns:1fr;gap:15px}.visual-key li{display:flex;gap:17px}.visual-key b{margin-top:1px}.visual-key p{margin:4px 0 0}.visual-key strong{font-size:.97rem}.level-pair{padding:19px 15px;gap:17px}.level-panel>.mono{font-size:.61rem;line-height:1.7;letter-spacing:0}.level-scale{flex-wrap:wrap;gap:6px;margin-top:12px}.level-scale span{font-size:.58rem}.level-panel>p{font-size:.73rem;line-height:1.7}.field-step{padding:18px 13px}.field-step svg{width:78px;height:78px;margin:11px 0}.field-step h3{font-size:1.07rem}.field-step strong{font-size:.77rem;line-height:1.8;display:block}.field-step p{font-size:.72rem}.lesson-exhibit .lab-visual,.lesson-exhibit .lab-controls{padding:21px 17px}.lesson-exhibit .lab canvas{height:260px}.lesson-exhibit .lab-results strong{font-size:1.4rem}.lesson-exhibit .lab-results{gap:18px}.lesson-exhibit .lab-notes{font-size:.67rem}.lesson-exhibit .wavelength-lab{padding:20px 17px}.lesson-exhibit .wave-controls{grid-template-columns:1fr;gap:21px}.lesson-exhibit .wave-results strong{font-size:1.3rem}.lesson-exhibit .wave-results{gap:16px}.lesson-exhibit .wave-results span{font-size:.7rem}.reading-transition{margin-top:13px}}
@media(prefers-reduced-motion:reduce){.lesson-art .academy-svg,.lesson-art img,.scene-heat{transition:none!important}.illustrated-card:hover .academy-svg,.illustrated-card:hover .lesson-photo img{transform:none}}
@media print{.academy-hero{padding:25px 0}.lesson-exhibit{break-inside:avoid}.visual-options,.visual-control input,.exhibit-hint{display:none}.exhibit-grid{display:block}.exhibit-controls{background:#eee;color:#111}.exhibit-heading,.exhibit-caption,.exhibit-controls{border-color:#aaa}.visual-insight h3,.visual-insight p,.control-footnote,.visual-answer span,.visual-answer strong{color:#111}.reading-transition{padding-top:15px}}
/* Short illustrations break up the deeper reading without adding another task. */
.concept-quartet{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px;margin:10px 0 30px}.concept-quartet>div{background:#0c1c2c;border:1px solid #29445d;padding:13px 13px 19px}.concept-quartet svg{width:100%;height:auto;display:block}.concept-quartet strong{display:block;color:#d8ebf9;font-size:.86rem;font-weight:500;margin:8px 0}.concept-quartet span{color:#8ba8c1;font-size:.72rem;line-height:1.8;display:block}.inline-figure{margin:12px 0 28px;border:1px solid #2c475f}.inline-figure figcaption{padding:17px 22px;font-size:.74rem;color:#8ba8c1;line-height:1.85;background:#0c1b2a}.sense-pair{display:grid;grid-template-columns:1fr 30px 1fr;gap:12px;align-items:center;margin:5px 0 26px;border-top:1px solid #2f4961;border-bottom:1px solid #2f4961;padding:20px 0}.sense-pair>div{display:flex;align-items:center;gap:10px}.sense-pair svg{width:82px;flex-shrink:0}.sense-pair strong,.sense-pair span{display:block}.sense-pair strong{font-size:.92rem;color:#c8e1f4;font-weight:500}.sense-pair span{font-size:.72rem;color:#82a1bb;margin-top:8px;line-height:1.7}.sense-pair .sense-plus{font-size:1.8rem;color:#4b708e;text-align:center;margin:0}
@media(max-width:800px){.concept-quartet{gap:12px}.concept-quartet>div{padding:10px 12px 16px}}
@media(max-width:520px){.concept-quartet{grid-template-columns:1fr 1fr;gap:12px}.concept-quartet>div{padding:9px 13px 18px}.concept-quartet strong{font-size:.88rem}.concept-quartet span{font-size:.71rem}.inline-figure figcaption{font-size:.69rem;padding:15px 18px}.sense-pair{grid-template-columns:1fr 18px 1fr;gap:10px}.sense-pair>div{display:block}.sense-pair svg{width:70px}.sense-pair strong{font-size:.88rem}.sense-pair span{font-size:.67rem}.exhibit-picture .academy-svg text{font-size:24px}}
html:not(.js) .lesson-exhibit input,html:not(.js) #acoustic-canvas,html:not(.js) #animation-toggle{display:none}

/* The diagrams stay on a dark canvas; reading and navigation use the light site. */
.first-lesson{display:grid;grid-template-columns:1fr 1fr;gap:45px;align-items:center;overflow:hidden;border-radius:28px;background:#f1f4f7;min-height:280px}.first-lesson>div:first-child{padding:35px 0 35px 42px}.first-lesson h2{font-size:29px;line-height:1.5;letter-spacing:-.025em;margin-bottom:21px}.first-lesson .eyebrow{font-size:13px;margin-bottom:19px}.first-lesson .link{font-size:15px}.first-lesson>div:last-child{position:relative;height:100%}.first-lesson img{width:100%;height:100%;min-height:280px;object-fit:cover}.first-lesson i{position:absolute;left:26%;top:45%;width:25%;aspect-ratio:1;border-radius:50%;transform:translate(-50%,-50%);background:radial-gradient(ellipse,#ff664bed,#febd53a9 25%,#58d0a680 42%,#4a9dc954 58%,transparent 73%)}
.learning-route{display:flex;gap:40px;flex-wrap:wrap;padding:32px 0;border-bottom:1px solid #dde4ea;margin-top:14px;font-size:13px;color:#7190a7}.learning-stage{padding-top:58px}.stage-heading{display:flex;align-items:center;gap:25px;margin-bottom:30px}.stage-heading>span{font-size:39px;color:#a0b4c3;font-weight:300;letter-spacing:-.065em}.stage-heading h2{font-size:31px;line-height:1.3}.stage-heading p{color:#9aa3ab;font-size:14px;margin-top:11px}.lesson-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:25px}.lesson-card{display:flex;flex-direction:column;border-radius:25px;overflow:hidden;background:#f5f6f8;transition:transform .2s;min-width:0}.lesson-card:hover{transform:translateY(-4px)}.lesson-art{aspect-ratio:2.12;height:auto;border:0;display:block;overflow:hidden}.lesson-art .lesson-photo{height:100%}.lesson-art .academy-svg{width:100%;height:100%}.lesson-card-copy{padding:25px;display:flex;flex-direction:column;flex:1}.lesson-meta{font-size:10px;display:flex;justify-content:space-between;gap:15px;color:#8b9eac}.lesson-card-copy h3{font-size:20px;line-height:1.55;color:#334d61;margin:18px 0 15px}.lesson-card-copy>p:not(.lesson-meta){font-size:13px;line-height:1.85;color:#8c98a2;margin:0 0 22px}.lesson-card-copy>.link{margin-top:auto;font-size:13px}.lesson-photo .photo-corner{color:#dae9f4}.page-knowledge .reading-help{margin:65px 0 45px}.reading-wrap{max-width:1140px}.breadcrumb{display:flex;gap:12px;flex-wrap:wrap;font-size:11px;color:#acb6bf;line-height:1.8;margin:33px 0 44px}.breadcrumb a{color:#7894aa}.reading-header{max-width:980px;padding-bottom:34px}.reading-header .eyebrow{font-size:12px;color:#a0a9b1;margin-bottom:20px}.reading-header h1{font-size:clamp(32px,4vw,53px);line-height:1.35;color:#273f52;letter-spacing:-.045em}.reading-header .lead{font-size:18px;color:#919da7;line-height:1.8;margin-top:23px}.reading-header .key-thought{display:flex;align-items:baseline;gap:22px;margin-top:26px;border-left:2px solid #85abc6;padding:3px 0 3px 19px}.reading-header .key-thought>span{font-size:11px;color:#7c9db7;white-space:nowrap}.reading-header .key-thought p{font-size:14px;line-height:1.9;color:#71899d;margin:0}.reading-transition{padding:43px 0 20px;margin-top:15px;font-size:12px;color:#a3adb6}.reading-layout{display:grid;grid-template-columns:minmax(0,1fr) 205px;gap:65px;align-items:start}.reading-toc{grid-column:2;grid-row:1;position:sticky;top:96px;padding-top:5px}.reading-toc>strong{font-size:11px;font-weight:500;color:#9daebb;display:block;margin-bottom:15px}.reading-toc nav{display:flex;flex-direction:column;gap:0}.reading-toc a{font-size:11px;line-height:1.85;color:#7995aa;display:block;padding:10px 0;border-bottom:1px solid #e0e6ec}.reading-toc a:hover{color:#285e82}.reading-body{grid-column:1;grid-row:1;min-width:0;padding-bottom:80px}.reading-section{border-top:1px solid #d8e1e9;padding:36px 0}.reading-section:first-child{padding-top:10px;border-top:0}.reading-section h2{font-size:25px;line-height:1.6;margin-bottom:24px;color:#3c5367;letter-spacing:-.015em}.reading-section h3{font-size:20px;line-height:1.6;margin-bottom:14px;color:#45627a}.reading-section p{font-size:16px;line-height:2;color:#8796a2;max-width:65ch}.reading-section p+p{margin-top:20px}.reading-section .text-link{color:#45799a;font-size:14px;display:inline-block;margin-top:24px}.source-note{font-size:11px!important;line-height:1.8!important;color:#a0b0bd!important;margin-top:23px!important}.source-note a{color:#829dad;text-decoration:underline;text-underline-offset:3px}.learning-note{padding:23px 25px;background:#f2f5f8;border-left:2px solid #a4bacb;border-radius:0 13px 13px 0;margin-top:25px}.learning-note strong{color:#58768d;font-size:14px;font-weight:500}.learning-note p{font-size:13px;margin-top:11px;line-height:1.95}.formula-block{background:#f4f6f8;border-radius:18px;border:1px solid #e0e7ed;padding:25px;margin:25px 0}.formula-block>strong{font:400 20px/1.8 ui-monospace,monospace;color:#6287a3}.formula-block p{font-size:12px;margin-top:12px;line-height:1.9}.signal-chain{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));margin:28px 0;border-top:1px solid #d0dce5;border-bottom:1px solid #d0dce5}.signal-chain>div{padding:22px 16px}.signal-chain>div+div{border-left:1px solid #dce5ec}.signal-chain b{font-size:10px;color:#8ba9be;font-weight:400}.signal-chain strong,.signal-chain span{display:block}.signal-chain strong{font-size:15px;margin:15px 0 8px;color:#627d92;font-weight:500}.signal-chain span{font-size:11px;color:#a3b2bd}.term-list{margin:0}.term-list>div{display:grid;grid-template-columns:130px minmax(0,1fr);gap:27px;padding:22px 0;border-bottom:1px solid #e0e6ec;line-height:1.95;font-size:14px}.term-list dt{color:#63849d;font-weight:500}.term-list dd{margin:0;color:#91a0ac}.reading-steps{margin:0;padding-left:25px;color:#8d9eaa}.reading-steps li{padding:0 0 20px 8px;font-size:15px;line-height:2}.reading-steps strong{color:#597a92;font-weight:500}.method-block{padding:23px 0}.method-block+.method-block{border-top:1px solid #dde5ec}.method-block .mono{display:block;color:#90abbe;font-size:11px;margin-bottom:17px}.path-diagram{padding:8px 23px;margin:25px 0;background:#f4f6f8;border:1px solid #e0e7ed;border-radius:17px}.path-diagram>div{padding:19px 0;display:flex;gap:24px;flex-wrap:wrap}.path-diagram>div+div{border-top:1px solid #d9e4ec}.path-diagram span{font-size:11px;color:#a0b1bf}.path-diagram strong{font-size:13px;color:#68869c;font-weight:400}.path-diagram i{font-style:normal;margin-inline:9px;color:#9eb8cb}.reading-boundary{border-top:1px solid #dce6ed;padding-top:24px;font-size:11px;color:#a7b7c3;line-height:1.9}.reading-boundary a{color:#749ab4}.lesson-pagination{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:32px;margin-top:40px}.lesson-pagination a{border-top:1px solid #beceda;padding-top:20px}.lesson-pagination span{display:block;font-size:11px;color:#8faabd;margin-bottom:13px}.lesson-pagination strong{font-size:16px;color:#66859d;font-weight:500;line-height:1.8}.lesson-pagination a:hover strong{color:#2b648b}
.lesson-exhibit{border:0;border-radius:24px;overflow:hidden;color:#d9ebf8;background:#0b1928;scroll-margin-top:90px}.exhibit-heading h2{color:#e4f1fa;font-weight:500;font-size:24px;line-height:1.55;letter-spacing:-.02em}.exhibit-heading{padding:26px 29px}.exhibit-heading .mono{color:#8fb0ca;font-size:10px}.exhibit-hint{font-size:11px;color:#9ac7e4;border-radius:20px;border-color:#49667e;padding:7px 11px}.exhibit-caption{font-size:10px!important;color:#92b0c7!important}.exhibit-grid{grid-template-columns:minmax(0,1fr) 275px}.exhibit-controls .control-prompt{color:#b5ccde}.exhibit-controls p{line-height:1.9}.exhibit-controls .visual-insight h3{color:#d9eafa;font-size:19px;letter-spacing:-.015em}.exhibit-controls .visual-insight p{color:#9ab5cb;font-size:13px}.exhibit-controls .control-footnote{font-size:10px;color:#7d9fb8}.visual-options button{font-size:12px;border-radius:18px}.visual-control label{font-size:12px}.visual-feedback{font-size:13px;color:#afc9dc}.visual-answer strong{font-size:29px}.visual-answer span{font-size:11px}.visual-key strong{color:#d1e7f6}.visual-key p{font-size:12px;color:#96b3c9}.field-step h3{color:#d8ebf9;font-size:20px}.field-step strong{font-size:13px}.field-step p{font-size:12px;color:#89abc4}.level-panel>p{color:#abcbe1;font-size:13px}.lesson-exhibit .lab{display:grid;grid-template-columns:minmax(0,1.3fr) minmax(280px,1fr)}.lesson-exhibit .lab-controls{border-left:1px solid #2d455b}.lab-heading button{border:1px solid #526e84;border-radius:20px;background:none;color:#b9d5e9;padding:8px 12px;font-size:11px}.lesson-exhibit .lab-visual .lab-heading{display:flex;align-items:center}.lab canvas{height:325px}.canvas-legend{display:flex;justify-content:center;gap:27px;margin:15px 0 24px;color:#91b4d0}.canvas-legend span{display:flex;align-items:center;gap:7px;font-size:11px}.canvas-legend i{height:2px;width:14px;background:#8bd8ff}.canvas-legend i.b{background:#6c83ff}.control-row{margin-bottom:29px}.control-label{display:flex;align-items:center;justify-content:space-between;gap:15px;font-size:13px;color:#bed7e9;margin-bottom:15px}.control-label output{color:#8bd8ff;font:400 13px ui-monospace,monospace}.control-row input{width:100%;accent-color:#8bd8ff}.range-limits{display:flex;justify-content:space-between;gap:10px;font-size:10px;line-height:1.8;color:#7d9fb8;margin-top:10px}.lab-results{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:25px;padding-top:24px;border-top:1px solid #36526c;margin-bottom:24px}.lab-results strong{display:block;font:400 25px/1.4 ui-monospace,monospace;color:#8bd8ff}.lab-results small{display:block;font-size:10px;color:#7fa4c0;margin-top:13px}.arrival-note{font-size:13px;color:#b3cfe3;line-height:1.9;margin-bottom:20px}.equation{font:400 11px/1.9 ui-monospace,monospace;color:#759dbb;margin-bottom:22px}.lesson-exhibit .lab-notes{font-size:10px;color:#799ebc;line-height:1.9}.wave-controls{display:grid;grid-template-columns:1fr 1fr;gap:36px}.wave-results{display:grid;grid-template-columns:1fr 1fr;gap:30px;padding-top:23px;margin:15px 0 25px;border-top:1px solid #2e4b66}.wave-results span{font-size:11px;color:#95b5cd;display:block}.wave-results strong{font:400 28px/1.7 ui-monospace,monospace;color:#b8e5ff;display:block;margin-top:7px}.wavelength-lab svg{width:100%;height:auto;display:block}.visual-noscript{color:#adcbdf;font-size:12px}.inline-figure{border:0;border-radius:20px;overflow:hidden}.inline-figure figcaption{background:#f2f5f8;color:#899eae;font-size:12px;line-height:1.9}.concept-quartet{gap:13px}.concept-quartet>div{background:#f2f5f8;border:1px solid #e4eaef;border-radius:16px}.concept-quartet svg g{stroke:#7a9cb6}.concept-quartet strong{color:#5d7e96;font-size:13px}.concept-quartet span{color:#93a9b9;font-size:11px}.sense-pair{border-color:#d3e0ea}.sense-pair strong{color:#597d97;font-size:14px}.sense-pair span{color:#96aebb;font-size:11px}.sense-pair .sense-plus{color:#b4c8d7}.sense-pair svg g{stroke:#85a4ba}
@media(max-width:1050px){.lesson-grid{gap:20px}.lesson-card-copy{padding:22px}.lesson-card-copy h3{font-size:18px}.first-lesson{gap:35px}.first-lesson>div:first-child{padding-left:35px}.first-lesson h2{font-size:25px}.reading-layout{gap:42px;grid-template-columns:minmax(0,1fr) 180px}.exhibit-grid{grid-template-columns:minmax(0,1fr) 245px}.exhibit-controls{padding:25px 22px}}
@media(max-width:800px){.lesson-grid{grid-template-columns:1fr}.lesson-card{display:grid;grid-template-columns:minmax(0,.9fr) minmax(0,1.1fr)}.lesson-art{height:100%;aspect-ratio:auto;min-width:0;display:flex;align-items:center;background:#0c1928}.lesson-art .academy-svg{height:auto;width:100%;min-height:100%}.lesson-art .lesson-photo{width:100%;height:100%}.lesson-card-copy{padding:26px}.lesson-card-copy h3{font-size:21px}.lesson-card-copy>p:not(.lesson-meta){font-size:14px}.first-lesson h2{font-size:23px}.first-lesson>div:first-child{padding:28px}.first-lesson{gap:0;min-height:250px}.first-lesson img{min-height:250px}.learning-route{gap:24px}.reading-layout{grid-template-columns:1fr;gap:30px}.reading-toc{position:static;grid-column:1;grid-row:1;border-top:1px solid #dae5ed;border-bottom:1px solid #dae5ed;padding:20px 0}.reading-toc nav{display:grid;grid-template-columns:1fr 1fr;gap:6px 20px}.reading-toc a{border:0;padding:6px 0;font-size:11px}.reading-body{grid-column:1;grid-row:2}.reading-header h1{font-size:40px}.reading-header .key-thought{display:block}.reading-header .key-thought p{margin-top:9px}.exhibit-grid{grid-template-columns:1fr}.exhibit-heading h2{font-size:22px}.exhibit-controls{padding:25px}.lesson-exhibit .lab{grid-template-columns:1fr}.lesson-exhibit .lab-controls{border-left:0;border-top:1px solid #2d455b}.lesson-exhibit .lab-results strong{font-size:26px}.visual-key{grid-template-columns:1fr 1fr 1fr}.visual-key p{font-size:12px}.lesson-exhibit .wave-controls{grid-template-columns:1fr 1fr}.reading-section p{font-size:16px}.reading-section h2{font-size:25px}.reading-help .link{white-space:normal}}
@media(max-width:520px){.first-lesson{grid-template-columns:1fr;border-radius:23px}.first-lesson>div:first-child{padding:29px}.first-lesson h2{font-size:25px;margin-bottom:19px}.first-lesson img{min-height:0;aspect-ratio:1.8;object-fit:cover}.first-lesson .eyebrow{font-size:12px;margin-bottom:16px}.learning-route{font-size:11px;gap:18px;justify-content:space-between;flex-wrap:wrap;padding-block:26px;margin-top:3px}.learning-stage{padding-top:35px}.stage-heading{gap:18px;margin-bottom:24px;align-items:flex-start}.stage-heading>span{font-size:31px;margin-top:1px}.stage-heading h2{font-size:26px}.stage-heading p{font-size:12px;line-height:1.85;margin-top:9px}.lesson-card{display:flex;border-radius:23px}.lesson-art{aspect-ratio:2.12;height:auto;display:block}.lesson-art .academy-svg{height:100%;min-height:0}.lesson-art .lesson-photo{height:100%}.lesson-card-copy{padding:25px}.lesson-card-copy h3{font-size:21px;margin-top:16px}.lesson-card-copy>p:not(.lesson-meta){font-size:13px}.lesson-meta{font-size:10px}.lesson-card-copy .link{font-size:12px}.page-knowledge .reading-help{margin:40px 0 32px}.breadcrumb{font-size:10px;gap:9px;margin:24px 0 31px}.reading-header h1{font-size:31px;line-height:1.45}.reading-header .lead{font-size:15px;line-height:1.85;margin-top:18px}.reading-header .eyebrow{font-size:10px;margin-bottom:16px}.reading-header .key-thought{margin-top:22px;padding-left:16px}.reading-header .key-thought>span{font-size:10px}.reading-header .key-thought p{font-size:13px;line-height:1.95}.reading-header{padding-bottom:29px}.lesson-exhibit{border-radius:19px}.exhibit-heading{padding:23px 20px;gap:13px}.exhibit-heading .mono{font-size:8px;letter-spacing:.06em}.exhibit-heading h2{font-size:19px;line-height:1.6}.exhibit-hint{font-size:10px;border:0;padding:0}.exhibit-controls{padding:23px 20px}.exhibit-caption{font-size:9px!important;padding:15px 20px;line-height:1.9!important}.exhibit-controls .visual-insight h3{font-size:18px}.exhibit-controls .visual-insight p{font-size:12px}.exhibit-controls .control-footnote{font-size:9px}.visual-control label{font-size:12px}.visual-answer strong{font-size:26px}.visual-key{grid-template-columns:1fr}.visual-key strong{font-size:15px}.visual-key p{font-size:11px}.field-step{padding:20px 14px}.field-step h3{font-size:17px}.field-step strong{font-size:11px}.field-step p{font-size:10px}.lesson-exhibit .lab-visual,.lesson-exhibit .lab-controls{padding:22px 18px}.control-label{font-size:12px}.range-limits{font-size:9px}.control-label output{font-size:12px}.lesson-exhibit .lab-results strong{font-size:22px}.lesson-exhibit .lab-results small{font-size:9px}.lesson-exhibit .lab-notes{font-size:9px}.equation{font-size:10px}.arrival-note{font-size:12px}.lesson-exhibit .wave-controls{grid-template-columns:1fr;gap:21px}.lesson-exhibit .wave-results strong{font-size:21px}.lesson-exhibit .wave-results span{font-size:10px}.lesson-exhibit .control-row{margin-bottom:0}.lesson-exhibit .lab-controls .control-row{margin-bottom:29px}.reading-transition{font-size:10px;padding:27px 0 19px;margin-top:7px}.reading-toc nav{grid-template-columns:1fr;gap:5px}.reading-toc a{font-size:11px}.reading-section{padding:30px 0}.reading-section h2{font-size:23px;margin-bottom:20px}.reading-section h3{font-size:19px}.reading-section p{font-size:15px;line-height:2}.reading-section p+p{margin-top:18px}.source-note{font-size:10px!important}.learning-note{padding:20px}.learning-note strong{font-size:13px}.learning-note p{font-size:12px}.formula-block{padding:20px}.formula-block>strong{font-size:17px}.formula-block p{font-size:11px}.signal-chain{grid-template-columns:1fr}.signal-chain>div{display:flex;align-items:center;gap:16px;flex-wrap:wrap;padding:18px 13px}.signal-chain>div+div{border-left:0;border-top:1px solid #dce5ec}.signal-chain strong{margin:0;font-size:14px}.signal-chain span{font-size:10px}.term-list>div{grid-template-columns:1fr;gap:9px;padding:20px 0;font-size:13px}.reading-steps li{font-size:14px}.path-diagram{padding:5px 18px}.path-diagram>div{display:block;padding-block:18px}.path-diagram strong{display:block;margin-top:12px;line-height:1.9;font-size:12px}.concept-quartet strong{font-size:13px}.concept-quartet span{font-size:10px}.sense-pair strong{font-size:13px}.sense-pair span{font-size:10px}.inline-figure figcaption{font-size:11px;padding:15px 18px}.lesson-pagination{gap:24px;margin-top:30px}.lesson-pagination strong{font-size:14px}.lesson-pagination span{font-size:10px}.reading-boundary{font-size:10px}.reading-body{padding-bottom:53px}}
@media(prefers-reduced-motion:reduce){.lesson-card{transition:none}.lesson-card:hover{transform:none}}

/* Readable supporting text on the light reading pages. */
.reading-section p,.reading-steps,.term-list dd{color:#5d6873}
.reading-header .lead,.reading-header .eyebrow,.reading-transition,.reading-boundary,.stage-heading p,.lesson-card-copy>p:not(.lesson-meta),.lesson-meta,.lesson-pagination span,.reading-help p{color:#65717c}
.learning-route,.breadcrumb,.breadcrumb a,.reading-toc>strong,.reading-toc a,.reading-header .key-thought p,.reading-header .key-thought>span,.lesson-pagination strong,.reading-boundary a{color:#536f86}
.signal-chain span,.signal-chain b,.path-diagram span,.path-diagram strong,.concept-quartet span,.sense-pair span,.inline-figure figcaption{color:#5e7384}
.formula-block>strong,.signal-chain strong,.term-list dt,.learning-note strong,.reading-steps strong,.concept-quartet strong,.sense-pair strong{color:#48677e}

.reading-section .source-note,.reading-section .source-note a{color:#536f86}

/* Arrival lesson: fixed physical scales and explicit reference-crest markers. */
.page-learn-array .lesson-exhibit .lab-visual>.lab-heading{justify-content:space-between;gap:12px;margin-bottom:15px}
.lab-speed{font-size:10px;line-height:1.6;color:#91b0c8}
.lesson-exhibit #acoustic-canvas{height:460px}
.page-learn-array .canvas-legend{flex-wrap:wrap;gap:10px 22px;margin:13px 0 20px}
.canvas-legend i.b{background:#a3aaff}
.canvas-legend i.reference{background:#ffd28a}
.frequency-facts{display:flex;flex-wrap:wrap;gap:9px 22px;margin-top:16px;color:#8caac2;font-size:11px}
.frequency-facts output{color:#bfdbed;margin-left:7px;font-variant-numeric:tabular-nums}
.arrival-times{display:grid;gap:8px;margin:-7px 0 19px;color:#92aec5;font-size:11px}
.arrival-times>span{display:flex;justify-content:space-between;gap:12px}
.arrival-times output{color:#ffd28a;font-variant-numeric:tabular-nums}
.lesson-exhibit .phase-explanation{font-size:11px;color:#a0bdd3;line-height:1.9;margin-bottom:17px}
.phase-explanation>span{color:#c1dcef;white-space:nowrap}
.page-learn-array .lab-results small{line-height:1.8}
.page-learn-array .lab-notes strong{color:#c2deef;font-weight:500}
@media(max-width:520px){.lesson-exhibit #acoustic-canvas{height:410px}.lab-speed{font-size:9px;max-width:150px}.page-learn-array .canvas-legend{gap:9px 14px}.page-learn-array .canvas-legend span{font-size:10px}.frequency-facts{gap:10px 18px}.page-learn-array .lab-results{gap:15px}.page-learn-array .lab-results strong{font-size:21px}.arrival-times{font-size:11px}.lesson-exhibit .phase-explanation{font-size:11px}}