/*
# @ctx:index[v:1|f:static/hub.css|e:7|n:0|i:-]
*/
@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Libre+Caslon+Display&display=swap');
:root{
  /* Atlas palette tokens — BT-ENERGY-01 */
  --canvas:#EDF5E7;
  --terrain:#BDE0B2;
  --water:#B6E2F1;
  --ink:#173A3A;
  --primary:#126B62;
  --discovery:#F2C94C;
  --surface:#FFFFFF;
  /* Subject territory tokens */
  --subject-physics:#C8BEEC;
  --subject-biology:#8ECFA9;
  --subject-computing:#80CBE3;
  --subject-mathematics:#F3D475;
  --subject-humanities:#F0AD91;
  /* Derived semantic tokens */
  --muted:rgba(23,58,58,0.6);
  --line:rgba(23,58,58,0.18);
  --accent:var(--primary);
  /* Legacy aliases kept for structural rules below */
  --paper:var(--canvas);
  /* Typography */
  --serif:'Libre Caslon Display',Georgia,serif;
  --sans:'DM Sans',Arial,sans-serif;
}
*{box-sizing:border-box}html{scroll-padding-top:100px}body{margin:0;background:var(--canvas);color:var(--ink);font:14px/1.5 var(--sans);-webkit-font-smoothing:antialiased}button,input,select{font:inherit;color:inherit}button,a,input,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button{border:0;background:none}a{color:inherit;text-decoration:none}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:2px solid var(--primary);outline-offset:5px}button:hover,a:hover{color:var(--primary)}[hidden]{display:none!important}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}.skip{position:absolute;top:-80px;left:24px;padding:12px;background:var(--canvas);z-index:50}.skip:focus{top:12px}.masthead{height:64px;margin:0;padding:0 20px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:30px}.wordmark{display:flex;align-items:center;gap:15px;font-size:18px;font-weight:600;letter-spacing:-.6px;line-height:1.25}.wordmark-note{display:block;font-size:10px;letter-spacing:.7px;font-weight:400;margin-top:5px}.mark{font-family:Georgia,serif;font-size:58px;line-height:.8;letter-spacing:-13px;margin-right:10px;transform:translateY(-4px)}.mark span{color:var(--primary)}nav{display:flex;gap:40px}.nav-link{padding:12px 0;font-size:12px}.nav-link.selected{color:var(--primary)}sup{font-size:9px;margin-left:5px}.search-toggle{font-size:12px;display:flex;gap:28px}.search-toggle span{font-size:20px}main{margin:0;padding:0 20px}.edition-line{display:flex;justify-content:space-between;margin-top:23px;font-size:9px;text-transform:uppercase;letter-spacing:1.5px;color:var(--muted)}.introduction{display:grid;grid-template-columns:1.5fr 1fr;align-items:end;padding:51px 0 48px;gap:30px}.introduction h1{font:clamp(54px,6.5vw,100px)/.96 var(--serif);letter-spacing:-3px;margin:0}.introduction>div{padding:0 0 3px 25%}.introduction p{font-size:14px;line-height:1.8;margin:0 0 20px}.text-link{display:inline-flex;gap:30px;font-size:11px;padding:7px 0;border-bottom:1px solid var(--ink)}.feature{display:grid;grid-template-columns:1.52fr 1fr;border-top:1px solid var(--ink);border-bottom:1px solid var(--ink);padding:26px 0;gap:44px;min-height:330px}.feature-media{position:relative;display:block;aspect-ratio:16/9;background:#dadad1;overflow:hidden;padding:0;text-align:left;width:100%}.feature-media img{width:100%;height:100%;object-fit:cover;filter:saturate(.7)}.feature-media::after{content:'';position:absolute;inset:60% 0 0;background:linear-gradient(transparent,#0006)}.play-label{position:absolute;z-index:1;bottom:22px;left:24px;background:var(--canvas);color:var(--ink);padding:11px 17px;display:flex;gap:25px;font-size:11px}.feature-text{display:flex;flex-direction:column;align-items:flex-start;justify-content:center;padding:12px 4% 12px 0}.eyebrow{font-size:9px;letter-spacing:1.6px;text-transform:uppercase}.feature-text .eyebrow{color:var(--primary);margin-bottom:20px}.feature-text h2{font:clamp(29px,3.3vw,48px)/1.07 var(--serif);letter-spacing:-.8px;margin:0 0 15px}.feature-text p{color:var(--muted);font-size:12px;line-height:1.8;max-width:370px;margin:0 0 20px}.byline{font-size:10px;letter-spacing:.1px;display:flex;flex-wrap:wrap;gap:8px;align-items:center}.dot{width:3px;height:3px;background:var(--muted);border-radius:50%;display:inline-block}.feature-bottom{margin-top:30px;display:flex;align-items:center;justify-content:space-between;width:100%}.save{font-size:11px;padding:8px 0}.save[aria-pressed=true]{color:var(--primary)}.catalog{padding:58px 0 70px;scroll-margin-top:25px}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:24px}.section-heading h2{font:39px/1.2 var(--serif);letter-spacing:-.5px;margin:0}.section-heading h2 span{font:11px var(--sans);vertical-align:top;margin-left:10px}.catalog-tools{display:flex;gap:25px;align-items:center}.search-field{display:flex;gap:15px;border-bottom:1px solid var(--line);align-items:center}.search-field input{border:0;background:none;font-size:11px;width:240px;padding:10px 0;outline-offset:0}select{background:none;border:0;font-size:10px;max-width:150px;padding:12px 0}.subjects{display:flex;gap:24px;flex-wrap:wrap;margin-top:31px;border-bottom:1px solid var(--line);padding-bottom:14px}.subjects button{font-size:11px;padding:8px 0;position:relative}.subjects button.selected{color:var(--primary)}.subjects button.selected::after{content:'';position:absolute;bottom:-15px;left:0;right:0;height:2px;background:var(--primary)}.view-options{display:flex;justify-content:space-between;align-items:center;padding:20px 0 27px;font-size:10px;color:var(--muted)}.view-options>div{display:flex;gap:18px}.small{padding:5px 0;font-size:10px;color:var(--muted)}.small.selected{color:var(--ink);text-decoration:underline;text-underline-offset:5px}.media-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));column-gap:20px;row-gap:32px}.media-item{min-width:0}.media-image{position:relative;aspect-ratio:16/9;width:100%;background:#dfded5;display:block;padding:0;overflow:hidden}.media-image img{width:100%;height:100%;object-fit:cover;filter:saturate(.65)}.media-image .duration{position:absolute;bottom:10px;right:10px;background:var(--canvas);padding:2px 7px;color:var(--ink);font-size:9px}.article-art{width:100%;height:100%;padding:25px;display:flex;align-items:end;justify-content:space-between;font:48px var(--serif);color:var(--muted);background:repeating-linear-gradient(0deg,transparent,transparent 22px,#cacac026 23px)}.item-topline{display:flex;justify-content:space-between;align-items:center;margin-top:14px}.item-topline .eyebrow{font-size:8px;color:var(--primary);letter-spacing:1px}.item-topline button{padding:5px;font-size:16px;line-height:1}.media-item h3{font-size:15px;line-height:1.4;letter-spacing:-.25px;font-weight:500;margin:7px 0 10px}.media-item h3 button{text-align:left;padding:0}.media-item .byline{color:var(--muted);font-size:10px}.empty{grid-column:1/-1;padding:70px 0;text-align:center;color:var(--muted)}.colophon{display:grid;grid-template-columns:.45fr 1.25fr 1fr;gap:50px;border-top:1px solid var(--ink);padding:48px 0 65px}.colophon-number{font-size:10px;color:var(--primary)}.colophon h2{font:43px/1.07 var(--serif);letter-spacing:-.8px;margin:0 0 20px}.colophon p{font-size:11px;line-height:1.9;color:var(--muted);max-width:330px}.collection-notes{padding-left:20px}.collection-notes h3{font-size:10px;font-weight:500;margin:0 0 21px}.collection-notes .text-link{display:table;font-size:10px;margin-top:8px}.collection-notes #sync-details{font-size:10px}footer{border-top:1px solid var(--line);margin:0;padding:16px 20px;display:flex;justify-content:space-between;font-size:9px;color:var(--muted)}footer>a{color:var(--ink);font-weight:600}.loading{padding:80px 0;color:var(--muted)}dialog{background:var(--canvas);color:var(--ink);border:1px solid var(--line);padding:0;width:min(1120px,94vw);max-height:93vh}dialog::backdrop{background:#17393999;backdrop-filter:blur(4px)}.reader-toolbar{position:sticky;top:0;z-index:3;background:var(--canvas);display:flex;justify-content:space-between;align-items:center;padding:16px 25px;border-bottom:1px solid var(--line)}.reader-toolbar button{font-size:11px;padding:10px}.reader-layout{display:grid;grid-template-columns:1.5fr 1fr}.reader-main{padding:25px;border-right:1px solid var(--line)}.player{aspect-ratio:16/9;background:var(--ink);width:100%;border:0}.reader-main h2{font:35px/1.15 var(--serif);margin:24px 0 12px}.reader-main>p{font-size:12px;color:var(--muted);line-height:1.8}.reader-actions{display:flex;gap:24px;flex-wrap:wrap;margin-top:25px}.reader-side{padding:25px}.reader-tabs{display:flex;gap:20px;border-bottom:1px solid var(--line);padding-bottom:12px;margin-bottom:24px}.reader-tabs button{font-size:11px;padding:5px 0}.reader-tabs .selected{color:var(--primary)}.reader-side h3{font:25px var(--serif);margin:22px 0 12px}.reader-side p,.reader-side li{font-size:12px;color:var(--muted);line-height:1.8}.reader-side ul{padding-left:17px}.cue{display:grid;grid-template-columns:46px 1fr;text-align:left;padding:10px 0;gap:9px;border-bottom:1px solid var(--line);width:100%;font-size:11px}.cue time{color:var(--primary);font-variant-numeric:tabular-nums}.transcript-list{max-height:420px;overflow:auto}.reader-side input{background:none;border:1px solid var(--line);padding:10px;width:100%;font-size:11px}.related-link{display:block;font-size:12px;text-align:left;border-bottom:1px solid var(--line);padding:12px 0;width:100%}.reader-side .text-link{font-size:10px}.map-intro{color:var(--muted);font-size:12px;margin:0 0 35px}#map-canvas{display:grid;grid-template-columns:repeat(3,1fr);gap:35px}.map-group{border-left:1px solid var(--line);padding:0 20px}.map-group h3{font:27px var(--serif);margin:0 0 15px;color:var(--primary)}#notice{position:fixed;bottom:25px;left:50%;transform:translateX(-50%);background:var(--ink);color:var(--canvas);font-size:12px;padding:14px 24px;opacity:0;pointer-events:none;z-index:20}#notice.visible{opacity:1}
@media(min-width:1500px){.media-grid{grid-template-columns:repeat(5,minmax(0,1fr))}}
@media(max-width:900px){nav{gap:22px}.masthead{gap:16px}.wordmark{font-size:15px}.search-toggle{display:none}.catalog-tools{gap:12px}.search-field input{width:185px}.media-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.reader-layout{grid-template-columns:1fr}.reader-main{border-right:0;border-bottom:1px solid var(--line)}#map-canvas{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){.media-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:600px){.masthead{height:auto;min-height:126px;flex-direction:column;align-items:flex-start;justify-content:center;gap:20px;padding:22px 0 13px}.mark{font-size:47px}.wordmark{font-size:17px}.wordmark-note{font-size:9px}nav{justify-content:space-between;width:100%;gap:10px}.nav-link{font-size:11px;padding:4px 0}.edition-line{font-size:7px;letter-spacing:.7px;margin-top:15px}.edition-line>span:last-child{display:none}.introduction{padding:34px 0;grid-template-columns:1fr;gap:24px}.introduction h1{font-size:65px;letter-spacing:-2px}.introduction>div{padding:0;display:flex;justify-content:space-between;align-items:end;gap:20px}.introduction p{font-size:11px;margin:0}.introduction .text-link{font-size:10px;gap:12px;white-space:nowrap}.feature{grid-template-columns:1fr;gap:21px;padding:18px 0 24px}.feature-text{padding:0}.feature-text .eyebrow{margin-bottom:13px}.feature-text h2{font-size:35px;max-width:400px}.feature-text p{max-width:none;font-size:12px;margin-bottom:12px}.feature-bottom{margin-top:18px}.catalog{padding-top:36px}.section-heading{align-items:start;flex-direction:column;gap:14px}.section-heading h2{font-size:36px}.catalog-tools{width:100%;justify-content:space-between}.search-field{flex:1}.search-field input{width:100%;font-size:10px}.catalog-tools select{max-width:120px;font-size:9px}.subjects{gap:17px;margin-top:20px;padding-bottom:10px}.subjects button{font-size:10px}.subjects button.selected::after{bottom:-11px}.view-options{align-items:start;gap:12px;font-size:9px;padding-bottom:20px}.view-options>div{gap:12px;white-space:nowrap}.small{font-size:9px;padding:0}.media-grid{column-gap:14px;row-gap:27px}.media-item h3{font-size:12px}.media-item .byline{font-size:9px}.item-topline .eyebrow{font-size:7px;letter-spacing:.3px}.item-topline{margin-top:9px}.duration{font-size:8px!important;bottom:6px!important;right:6px!important}.colophon{grid-template-columns:1fr;gap:25px;padding:30px 0}.colophon h2{font-size:38px}.collection-notes{padding:0}.colophon p{max-width:100%}.colophon-number{font-size:9px}.collection-notes h3{margin-bottom:12px}footer{flex-wrap:wrap;gap:14px;font-size:8px}footer>span:last-child{width:100%}.reader-main,.reader-side{padding:18px}.reader-main h2{font-size:29px}.reader-toolbar{padding:10px 15px}.reader-actions{gap:15px}.text-link{gap:12px}#map-canvas{grid-template-columns:1fr}.play-label{bottom:15px;left:15px;padding:9px 13px}.article-art{font-size:30px;padding:15px}}
.introduction>*{min-width:0}.item-topline{gap:8px}.item-topline .eyebrow{min-width:0;overflow-wrap:anywhere}.item-topline button{flex-shrink:0}.media-item h3,.byline{overflow-wrap:anywhere}.byline>span{min-width:0}.feature-text,.reader-main,.reader-side{min-width:0}
@media(max-width:360px){.introduction h1{font-size:55px}.introduction>div{flex-wrap:wrap;gap:12px}.feature-bottom{flex-wrap:wrap;gap:12px}.section-heading h2{font-size:32px}.search-field{min-width:0}.catalog-tools select{max-width:105px}.media-grid{grid-template-columns:1fr}.colophon h2{font-size:34px}}
/* Snippet cards — Twitter/X text items inline between videos */
.snippet-card{grid-column:span 2;display:flex;flex-direction:column;gap:10px;padding:22px 24px;background:var(--surface);border:1px solid var(--line);border-left:3px solid var(--primary);text-decoration:none;color:inherit}
.snippet-card:hover{border-left-color:var(--ink)}
.snippet-text{font-size:13px;line-height:1.75;color:var(--muted);margin:0;font-style:italic}
.snippet-cta{font-size:10px;letter-spacing:.8px;text-transform:uppercase;color:var(--primary)}
@media(max-width:600px){.snippet-card{grid-column:span 2}}
@media(max-width:480px){.snippet-card{grid-column:1/-1}}
/* BrainTube: video-first workspace */
.masthead{position:sticky;top:0;z-index:5;height:64px;background:var(--canvas)}
.wordmark{font-size:25px}.mark{font-size:46px;letter-spacing:-7px}.mark span{font:17px var(--sans);display:inline-block;margin-left:4px}.wordmark-note{font-size:9px}
.nav-link{display:flex;align-items:center;gap:9px;min-height:44px}.nav-link>span{font-size:21px}.search-toggle{min-height:44px}
.introduction{display:flex;justify-content:space-between;align-items:center;padding:26px 0}.introduction h1{font-size:38px;letter-spacing:-1px}.introduction>div{padding:0}.edition-line{margin-top:16px}
.feature{padding:0 0 24px;border-top:0;gap:30px}.feature-text h2{font-size:39px}.feature-text p{display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden}.feature-media img,.media-image img{filter:none}
.catalog{padding-top:28px}.subjects{flex-wrap:nowrap;overflow:auto;scrollbar-width:none;gap:10px;padding:5px 0 12px;margin-top:20px}.subjects button{flex-shrink:0;padding:10px 16px;min-height:44px;background:var(--terrain);border-radius:3px}.subjects button.selected{background:var(--ink);color:var(--canvas)}.subjects button.selected::after{display:none}
button{touch-action:manipulation}.media-item h3{font-size:18px}.media-item .byline{font-size:12px}.media-image::after{content:'▶';position:absolute;left:50%;top:50%;display:grid;place-items:center;width:54px;height:54px;background:rgba(237,245,231,0.93);border-radius:50%;color:var(--ink);opacity:0;transform:translate(-50%,-50%)}.media-image:hover::after{opacity:1}.icon-save{min-width:44px;min-height:44px}.save[aria-pressed=true]{color:var(--primary)}.reader-actions>*{min-height:44px;align-items:center}.reader-tabs{overflow:auto;gap:20px}.reader-tabs button{min-height:44px;white-space:nowrap}.reader-side p{overflow-wrap:anywhere}.reader-toolbar button{min-height:44px}
.reader-side{}.comments{margin-top:28px;border-top:1px solid var(--line);padding-top:18px}.comments h3{font:26px var(--serif);margin:0 0 7px}.comment-note{font-size:11px;color:var(--muted)}.comment{display:grid;grid-template-columns:34px 1fr;gap:12px;padding:18px 0;border-bottom:1px solid var(--line)}.comment-avatar{display:grid;place-items:center;width:34px;height:34px;border-radius:50%;background:var(--terrain);font:20px var(--serif)}.comment a{font-size:12px;font-weight:600}.comment p{font-size:13px;line-height:1.7;white-space:pre-wrap;overflow-wrap:anywhere;margin:7px 0}.comment small{color:var(--muted);font-size:10px}.comment-body{min-width:0}.comments summary{cursor:pointer;min-height:44px;padding:14px 0;font-size:12px}
@media(max-width:700px){
 body{padding-bottom:calc(78px + env(safe-area-inset-bottom))}html{scroll-padding-top:85px}main{margin:0 20px}.masthead{margin:0;padding:10px 20px;height:76px;min-height:76px;flex-direction:row;align-items:center;gap:12px;border-bottom:1px solid var(--line)}.wordmark{font-size:26px;gap:10px}.wordmark-note{font-size:8px}.mark{font-size:42px}.search-toggle{display:flex;font-size:0;gap:0;min-width:44px;justify-content:center}.search-toggle span{font-size:26px}
 nav{position:fixed;bottom:0;left:0;right:0;z-index:10;display:flex;width:100%;gap:0;justify-content:space-around;background:var(--canvas);border-top:1px solid var(--line);padding:7px 12px calc(7px + env(safe-area-inset-bottom));box-shadow:0 -8px 25px rgba(23,58,58,0.04)}.nav-link{flex:1;flex-direction:column;gap:2px;font-size:10px;padding:5px;min-height:54px;position:relative}.nav-link>span{font-size:23px;line-height:1.2}.nav-link.selected::before{content:'';position:absolute;top:-8px;height:2px;background:var(--primary);width:34px}.nav-link sup{position:absolute;top:5px;left:calc(50% + 13px);margin:0;font-size:9px}
 .edition-line{font-size:8px;letter-spacing:.5px}.introduction{padding:20px 0;gap:12px}.introduction h1{font-size:30px;line-height:1.05;letter-spacing:-.6px;max-width:235px}.introduction .text-link{font-size:10px}.feature{display:flex;flex-direction:column;gap:16px;padding-bottom:23px}.feature-media{width:calc(100% + 40px);margin-left:-20px;aspect-ratio:16/9}.feature-text{padding:0}.feature-text h2{font:25px/1.16 var(--sans);letter-spacing:-.7px;font-weight:500;margin-bottom:12px}.feature-text .eyebrow{font-size:9px;margin-bottom:10px}.feature-text p{display:none}.feature-text .byline{font-size:12px}.feature-bottom{margin-top:10px;gap:10px}.feature-bottom>*{min-height:44px;display:flex;align-items:center;font-size:11px}.play-label{bottom:16px;left:20px;min-height:44px;align-items:center}
 .section-heading{gap:16px}.section-heading h2{font:28px var(--serif)}.catalog-tools{gap:12px}.search-field{min-width:0}.search-field input{font-size:16px;min-height:44px;min-width:0}.catalog-tools select{min-height:44px;font-size:11px;max-width:116px}.subjects{margin-right:-20px;margin-left:-20px;padding-left:20px;padding-right:20px}.subjects button{font-size:12px}.view-options{align-items:center;padding:12px 0 18px;font-size:10px;gap:8px}.view-options>div{gap:10px}.small{min-height:44px;font-size:11px}.media-grid{grid-template-columns:1fr;gap:28px}.media-item .media-image{width:calc(100% + 40px);margin-left:-20px}.media-item h3{font-size:20px;line-height:1.35;margin:0 0 8px}.media-item h3 button{min-height:44px}.item-topline{margin-top:7px}.item-topline .eyebrow{font-size:9px;letter-spacing:.8px}.media-item .byline{font-size:12px}.media-image .duration{font-size:11px!important;bottom:12px!important;right:16px!important}.colophon{grid-template-columns:1fr}.colophon-number{display:none}.colophon h2{font-size:30px}.colophon p{font-size:12px}.collection-notes{padding:0}footer{margin:0 20px}
 dialog{width:100%;max-width:100%;height:100dvh;max-height:100dvh;margin:0;border:0;border-radius:0;overscroll-behavior:contain}.reader-toolbar{padding:calc(6px + env(safe-area-inset-top)) 16px 6px}.reader-layout{display:block}.reader-main{padding:0 20px 24px}.player{display:block;width:calc(100% + 40px);max-width:none;margin-left:-20px}.reader-main h2{font:24px/1.25 var(--sans);letter-spacing:-.5px;margin-top:20px}.reader-main .byline{font-size:12px}.reader-side{padding:12px 20px calc(24px + env(safe-area-inset-bottom))}.reader-tabs{position:sticky;top:62px;background:var(--canvas);z-index:2;gap:25px}.reader-side input{font-size:16px;min-height:44px}.cue{min-height:44px;font-size:13px}.related-link{font-size:14px;min-height:44px}.reader-side p,.reader-side li{font-size:14px}#notice{bottom:calc(90px + env(safe-area-inset-bottom));max-width:90vw;width:max-content}.article-art{font-size:42px}.transcript-list{max-height:50dvh}
}
@media(prefers-reduced-motion:reduce){/* Zero-motion mandate active; no authored animations or transitions exist to disable. */}
/* Auth */
.auth-mount{display:flex;align-items:center;flex-shrink:0}
.sign-in-btn{font-size:11px;padding:7px 14px;border:1px solid var(--ink);color:var(--ink);background:none;cursor:pointer;white-space:nowrap}
.sign-in-btn:hover{background:var(--ink);color:var(--canvas)}

/* ============================================================
   BT-ENERGY-04 — Atlas shell styles
   Zero transitions, zero animations, zero will-change.
   ============================================================ */

/* Status rail */
.status-rail{display:none}
.sr-visible{color:var(--primary);font-weight:600}
/* Colophon links */
.colophon-links{display:flex;gap:24px;padding:20px 0;border-top:1px solid var(--line);margin-top:40px}

/* Atlas container — hidden; grid view is the default explore experience */
.atlas-container{display:none}
@media(max-width:700px){.atlas-container{height:calc(100dvh - 140px)}}
@media(max-width:360px){.atlas-container{height:calc(100dvh - 120px)}}

/* Atlas map wrapper (SVG + landmark overlay) */
.atlas-map-wrap{position:relative;width:100%;height:100%}

/* Territory SVG — fills the full container */
.atlas-svg{position:absolute;inset:0;width:100%;height:100%;display:block}
.atlas-territory-label{font:10px/1 var(--sans);fill:var(--ink);pointer-events:none;font-weight:500;text-transform:uppercase;letter-spacing:.8px}

/* Landmark overlay — absolutely positioned cards */
.atlas-landmarks{position:absolute;inset:0;pointer-events:none}

/* Landmark card */
.landmark{position:absolute;transform:translate(-50%,-50%);pointer-events:all;cursor:pointer;width:80px;min-height:56px;background:var(--surface);border:1px solid var(--line);border-radius:3px;overflow:hidden;display:flex;flex-direction:column;touch-action:manipulation;min-width:44px}
.landmark:hover{border-color:var(--primary)}
.landmark:focus-visible{outline:2px solid var(--primary);outline-offset:2px}
.landmark.selected{border:2px solid var(--primary);box-shadow:0 2px 8px rgba(23,58,58,0.18)}
/* Ensure 44×44 touch target minimum via padding extension */
.landmark::before{content:'';position:absolute;inset:-4px;pointer-events:none}

/* Landmark thumbnail */
.landmark-thumb{position:relative;width:100%;height:36px;background:var(--terrain);flex-shrink:0;display:flex;align-items:center;justify-content:center;overflow:hidden}
.landmark-thumb img{width:100%;height:100%;object-fit:cover}
.landmark-thumb-glyph{font-size:14px;color:var(--surface);line-height:1}
.landmark-duration{position:absolute;bottom:3px;right:4px;background:var(--canvas);color:var(--ink);font-size:8px;padding:1px 4px;border-radius:2px;line-height:1.4}

/* Landmark label row */
.landmark-label{display:flex;align-items:center;gap:4px;padding:3px 5px;min-height:20px;background:var(--surface)}
.landmark-subject-dot{width:6px;height:6px;border-radius:50%;flex-shrink:0}
.landmark-title{font-size:9px;font-weight:500;color:var(--ink);line-height:1.3;overflow:hidden;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;min-width:0}

/* Accessible list (atlas alternative) — shown when list-view toggle is active */
.atlas-accessible-list{list-style:none;margin:0;padding:0;display:none}
.atlas-accessible-list:not([hidden]){display:block}
.atlas-list-item-btn{display:flex;align-items:center;gap:12px;width:100%;text-align:left;padding:12px 0;border:0;background:none;cursor:pointer;border-bottom:1px solid var(--line);min-height:44px;color:var(--ink)}
.atlas-list-item-btn:hover{color:var(--primary)}
.atlas-list-item-btn.selected{color:var(--primary)}
.atlas-list-item-btn:focus-visible{outline:2px solid var(--primary);outline-offset:2px}
.atlas-list-dot{width:8px;height:8px;border-radius:50%;flex-shrink:0}
.atlas-list-content{display:flex;flex-direction:column;gap:3px;min-width:0}
.atlas-list-title{font-size:14px;font-weight:500;line-height:1.4;overflow-wrap:anywhere}
.atlas-list-meta{font-size:11px;color:var(--muted)}

/* More button */
.atlas-more-btn{display:block;width:100%;padding:14px;margin-top:14px;text-align:center;font-size:11px;border:1px solid var(--line);background:none;color:var(--ink);cursor:pointer;min-height:44px}
.atlas-more-btn:hover{color:var(--primary)}

/* Preview tray — fixed above the dock */
.preview-tray{position:fixed;bottom:calc(60px + env(safe-area-inset-bottom));left:0;right:0;z-index:8;background:var(--surface);border-top:1px solid var(--ink);padding:12px 20px;max-width:100%}
@media(min-width:701px){.preview-tray{max-width:600px;left:50%;transform:translateX(-50%);border:1px solid var(--ink);bottom:20px}}
.preview-tray-inner{display:flex;align-items:center;gap:12px;min-width:0}
.preview-tray-thumb{width:64px;height:48px;flex-shrink:0;background:var(--terrain);overflow:hidden;border-radius:2px;display:flex;align-items:center;justify-content:center}
.preview-tray-thumb img{width:100%;height:100%;object-fit:cover}
.preview-thumb-placeholder{font-size:18px;color:var(--surface)}
.preview-tray-body{flex:1;min-width:0}
.preview-tray-title{font-size:14px;font-weight:600;color:var(--ink);line-height:1.3;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;margin-bottom:4px}
.preview-tray-meta{font-size:11px;color:var(--muted);display:flex;flex-wrap:wrap;gap:4px;align-items:center}
.preview-dot{color:var(--muted)}
.preview-tray-actions{display:flex;flex-direction:column;gap:6px;flex-shrink:0;align-items:flex-end}
.preview-open-btn{background:var(--primary);color:var(--surface);font-size:12px;font-weight:600;padding:8px 16px;min-height:44px;min-width:64px;border:0;cursor:pointer;border-radius:2px}
.preview-open-btn:hover{opacity:.9}
.preview-save-btn{background:none;border:1px solid var(--line);font-size:16px;min-width:44px;min-height:44px;cursor:pointer;color:var(--ink)}
.preview-save-btn[aria-pressed="true"]{color:var(--primary)}
.preview-dismiss{position:absolute;top:8px;right:8px;background:none;border:0;font-size:20px;cursor:pointer;color:var(--muted);min-width:44px;min-height:44px;display:flex;align-items:center;justify-content:center;padding:0}
.preview-dismiss:hover{color:var(--ink)}

/* Atlas static list (hub.html #atlas-list) */
.atlas-list{list-style:none;margin:0;padding:0}

/* Desktop: wider landmark cards */
@media(min-width:667px){
  .landmark{width:96px;min-height:68px}
  .landmark-thumb{height:44px}
  .landmark-title{font-size:10px}
  .landmark-duration{font-size:9px}
}

/* 320px minimum: tighter touch targets, single-col */
@media(max-width:360px){
  .atlas-container{height:calc(100dvh - 110px)}
  .landmark{width:68px;min-height:48px}
  .landmark-thumb{height:28px}
  .preview-tray{padding:8px 12px}
  .preview-tray-title{font-size:13px}
  .preview-tray-thumb{width:48px;height:36px}
  .status-rail{gap:8px;font-size:8px}
}

/* ============================================================
   BT-ENERGY-05 — Search / Filter / Preview additions
   Zero transitions, zero animations per motion mandate.
   ============================================================ */

/* Subject filter pills — replaces bare .subjects button styling */
.subject-pill{font-size:11px;padding:8px 14px;min-height:44px;background:transparent;color:var(--ink);border:1px solid var(--line);border-radius:2px;cursor:pointer}
.subject-pill.selected{background:var(--terrain);color:var(--ink);border-color:var(--terrain)}
.subject-pill:hover{border-color:var(--primary)}

/* Subject badge — colored pill used in preview tray */
.subject-badge{display:inline-block;padding:2px 8px;border-radius:10px;font-size:10px;font-weight:500;color:var(--ink)}
.subject-badge--physics{background:var(--subject-physics)}
.subject-badge--biology{background:var(--subject-biology)}
.subject-badge--computing{background:var(--subject-computing)}
.subject-badge--mathematics{background:var(--subject-mathematics)}
.subject-badge--humanities{background:var(--subject-humanities)}
.subject-badge--open{background:var(--terrain)}

/* Source domain label in preview tray meta */
.preview-source-domain{color:var(--muted);font-size:10px}

/* Tray Watch button (primary CTA) */
.tray-watch-btn{background:var(--primary);color:var(--surface);font-size:12px;font-weight:600;padding:8px 16px;min-height:44px;min-width:64px;border:0;cursor:pointer;border-radius:2px}
.tray-watch-btn:hover{opacity:.9}

/* Tray Read / Read excerpt / Open original button */
.tray-read-btn{display:inline-flex;align-items:center;justify-content:center;background:none;border:1px solid var(--primary);color:var(--primary);font-size:12px;font-weight:600;padding:8px 16px;min-height:44px;min-width:64px;cursor:pointer;border-radius:2px;text-decoration:none}
.tray-read-btn:hover{background:var(--primary);color:var(--surface)}

/* Tray dismiss × button (top-right of tray) */
.tray-dismiss{position:absolute;top:8px;right:8px;background:none;border:0;font-size:20px;cursor:pointer;color:var(--muted);min-width:44px;min-height:44px;display:flex;align-items:center;justify-content:center;padding:0}
.tray-dismiss:hover{color:var(--ink)}

/* Results status — live region text (small, muted) */
.results-status{font-size:10px;color:var(--muted);font-style:italic}

/* ============================================================
   BT-ENERGY-06 — Watch view & source conversation
   Zero transitions, zero animations per motion mandate.
   ============================================================ */

/* Subject band — 4px colored top strip inside dialog content, above layout */
.subject-band{height:4px;width:100%;background:var(--subject-band-color,var(--terrain))}

/* Reader toolbar layout: left group (eyebrow + educator + badge) + close */
.reader-toolbar-left{display:flex;align-items:center;gap:10px;min-width:0}
.reader-toolbar-educator{font-size:11px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:200px}
.reader-toolbar-subject{font-size:10px;font-weight:500;padding:2px 8px;border-radius:10px}

/* Watch context band — subject badge · channel · duration below player */
.watch-context-band{display:flex;align-items:center;gap:12px;padding:10px 0 6px;flex-wrap:wrap;border-bottom:1px solid var(--line);margin-bottom:10px}
.ctx-channel{flex:1;font-size:12px;color:var(--muted);min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ctx-channel a{color:var(--muted);text-decoration:underline;text-underline-offset:3px}
.ctx-channel a:hover{color:var(--primary)}
.ctx-duration{font-size:11px;color:var(--muted);white-space:nowrap;padding:2px 8px;background:var(--canvas);border:1px solid var(--line);border-radius:2px}

/* Reader tabs — selected tab has static bottom border; no transition */
.reader-tabs button[aria-selected="true"]{color:var(--primary);border-bottom:2px solid var(--primary)}
.reader-tabs button[aria-selected="false"]{border-bottom:2px solid transparent}

/* Transcript unavailable notice */
.transcript-unavailable{padding:16px 0}
.transcript-unavailable p{font-size:12px;color:var(--muted);font-style:italic;margin:0 0 10px}

/* Comment avatar — uses CSS custom property for background color */
.comment-avatar{background:var(--avatar-bg,var(--terrain))}

/* Embed fallback */
.embed-fallback{padding:24px;background:var(--canvas);border:1px solid var(--line);text-align:center}
.embed-fallback p{font-size:13px;color:var(--muted);margin:0 0 10px}

/* ============================================================
   BT-ENERGY-07 — Personal field collection view
   Zero transitions, zero animations per motion mandate.
   ============================================================ */

/* Collection view wrapper */
#collection-view{padding:24px 0 48px}
#collection-view h2{font:32px/1.2 var(--serif);letter-spacing:-.4px;margin:0 0 28px;color:var(--ink)}

/* Subject group */
.collection-subject-group{margin-bottom:36px}
.collection-group-heading{font-size:11px;font-weight:600;text-transform:uppercase;letter-spacing:1.2px;color:var(--primary);margin:0 0 14px;padding-bottom:8px;border-bottom:1px solid var(--line)}
.collection-group-items{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px}

/* Collection item card — min 44px touch target per interactive controls */
.collection-item{display:grid;grid-template-columns:88px 1fr auto;gap:12px;align-items:start;background:var(--surface);border:1px solid var(--line);border-radius:3px;padding:12px;min-height:44px;position:relative}

/* Explored state — subtle left border using --terrain token */
.collection-item.explored{border-left:3px solid var(--terrain)}

/* Thumbnail */
.collection-item-thumb{width:88px;height:62px;background:var(--terrain);overflow:hidden;border-radius:2px;flex-shrink:0;display:flex;align-items:center;justify-content:center}
.collection-item-thumb img{width:100%;height:100%;object-fit:cover}
.collection-thumb-placeholder{font-size:20px;color:var(--surface)}

/* Body */
.collection-item-body{min-width:0;display:flex;flex-direction:column;gap:6px}
.collection-item-title{font-size:14px;font-weight:500;line-height:1.4;color:var(--ink);overflow-wrap:anywhere}
.collection-item-title button{text-align:left;font-size:14px;font-weight:500;line-height:1.4;color:var(--ink);padding:0;min-height:44px;display:block;width:100%}
.collection-item-title button:hover{color:var(--primary)}
.collection-item-meta{display:flex;flex-wrap:wrap;gap:6px;align-items:center;font-size:11px;color:var(--muted)}
.collection-item-educator{color:var(--muted)}
.collection-item-kind{font-size:10px;text-transform:uppercase;letter-spacing:.8px;color:var(--muted);padding:2px 6px;border:1px solid var(--line);border-radius:2px}

/* Explore checkbox label */
.collection-item-explore{display:flex;align-items:center;gap:8px;font-size:11px;color:var(--muted);cursor:pointer;min-height:44px;padding:4px 0}
.collection-item-explore input[type="checkbox"]{width:16px;height:16px;flex-shrink:0;accent-color:var(--primary);cursor:pointer}
.collection-item-explore:hover{color:var(--ink)}

/* Remove button */
.collection-item-remove{min-width:44px;min-height:44px;font-size:18px;display:flex;align-items:center;justify-content:center;color:var(--muted);border:1px solid var(--line);border-radius:2px;background:none;cursor:pointer;flex-shrink:0;align-self:start}
.collection-item-remove:hover{color:var(--primary);border-color:var(--primary)}
.collection-item-remove[aria-pressed="true"]{color:var(--primary)}

/* Empty state */
.collection-empty{padding:60px 0;text-align:center;color:var(--muted);font-size:14px;grid-column:1/-1}

/* Notice undo button (inside the #notice toast) */
.notice-undo-btn{display:inline;background:none;border:0;color:var(--canvas);text-decoration:underline;font-size:12px;padding:0;cursor:pointer;font:inherit;min-height:0}
.notice-undo-btn:hover{opacity:.85}

/* Responsive: single column on narrow screens */
@media(max-width:700px){
  .collection-group-items{grid-template-columns:1fr}
  .collection-item{grid-template-columns:72px 1fr auto}
  .collection-item-thumb{width:72px;height:50px}
  #collection-view h2{font-size:26px}
}

/* ============================================================
   BT-ENERGY-08 — Subject trails view
   Zero transitions, zero animations per motion mandate.
   ============================================================ */

#trails-view{padding:32px 0 64px}
.trails-intro{font-size:12px;color:var(--muted);margin:4px 0 0}

.trails-grid{display:grid;grid-template-columns:1fr;gap:1.5rem;padding:1rem 0}

.trail-section{background:var(--surface);border:1px solid var(--line);border-radius:6px;padding:1.25rem}

.trail-header{display:flex;align-items:center;gap:0.75rem;margin-bottom:1rem}

.trail-dot{width:12px;height:12px;border-radius:50%;flex-shrink:0}

.trail-header h3{font:18px/1.2 var(--serif);letter-spacing:-.3px;margin:0;flex:1}

.trail-count-badge{font-size:0.75rem;color:var(--muted);background:var(--canvas);padding:0.1rem 0.4rem;border-radius:3px}

.trail-items{list-style:none;padding:0;margin:0 0 0.75rem}

.trail-item{padding:0.5rem 0;border-bottom:1px solid var(--line);cursor:pointer;display:flex;align-items:flex-start;gap:0.5rem}
.trail-item:last-child{border-bottom:none}
.trail-item:hover .trail-item-title{color:var(--primary)}

.trail-item-title{font-size:0.875rem;color:var(--ink);flex:1;overflow-wrap:anywhere}

.trail-item-format{font-size:0.7rem;color:var(--muted);flex-shrink:0;text-transform:uppercase;letter-spacing:.5px;padding-top:2px}

.trail-show-more{background:none;border:1px solid var(--line);color:var(--primary);font-size:0.8rem;padding:0.3rem 0.6rem;cursor:pointer;border-radius:3px;margin-bottom:0.75rem;min-height:44px}
.trail-show-more:hover{background:var(--canvas)}

.trail-bridges{background:var(--canvas);border-radius:4px;padding:0.75rem;font-size:0.8rem;color:var(--muted)}

.trail-bridges-title{font-weight:600;color:var(--ink);margin-bottom:0.4rem;font-size:0.8rem}

.trail-bridge-item{margin-bottom:0.25rem;overflow-wrap:anywhere}
.trail-bridge-item:last-child{margin-bottom:0}

@media(min-width:768px){.trails-grid{grid-template-columns:repeat(2,1fr)}}

@media(max-width:700px){#trails-view{padding:20px 0 48px}.trail-section{padding:1rem}.trail-header h3{font-size:16px}}