:root{color-scheme:dark;--bg:#07111f;--surface:#0c1a2a;--line:#22364d;--text:#edf5ff;--muted:#9bb0c7;--accent:#f5c76f}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,sans-serif}.twilight-page{width:min(1120px,calc(100% - 32px));margin:0 auto;padding:48px 0 72px}.twilight-page>small{color:var(--accent);letter-spacing:.12em}.twilight-page h1{max-width:780px;font-size:clamp(2rem,5vw,4rem);line-height:1.02;margin:12px 0}.twilight-page>p{max-width:760px;color:var(--muted);line-height:1.7}.twilight-lab{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(280px,.65fr);gap:16px;margin:32px 0;align-items:start}.twilight-view,.twilight-controls,.twilight-copy{border:1px solid var(--line);border-radius:18px;background:var(--surface);padding:18px}.twilight-sky{position:relative;min-height:360px;overflow:hidden;border-radius:14px;background:linear-gradient(#6ea8dc,#f2b46d 72%,#1a2530);transition:background .2s}.twilight-sky[data-sky-phase=civil]{background:linear-gradient(#244d79,#df7d5b 72%,#131d2a)}.twilight-sky[data-sky-phase=nautical]{background:linear-gradient(#0d2342,#5c4260 74%,#0b1420)}.twilight-sky[data-sky-phase=astro]{background:linear-gradient(#07152b,#28233e 76%,#07101c)}.twilight-sky[data-sky-phase=night]{background:radial-gradient(circle at 50% 80%,#111b32,#040914 70%)}.twilight-sun{position:absolute;left:50%;width:54px;height:54px;transform:translate(-50%,50%);border-radius:50%;background:#ffe3a0;box-shadow:0 0 42px #f6b95f}.twilight-metrics{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin-top:10px}.twilight-metrics div{min-width:0;padding:12px;border:1px solid var(--line);border-radius:12px}.twilight-metrics small{display:block;color:var(--muted)}.twilight-metrics strong{display:block;margin-top:5px;overflow-wrap:anywhere}.twilight-controls label{display:grid;gap:12px;color:var(--muted)}.twilight-controls input{width:100%}.twilight-tip,.twilight-fact{line-height:1.65}.twilight-tip{font-size:1.02rem}.twilight-fact{color:var(--muted)}.twilight-flow{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.twilight-copy p{color:var(--muted);line-height:1.65}.twilight-links{display:flex;flex-wrap:wrap;gap:8px}.twilight-links a{color:var(--text);border:1px solid var(--line);border-radius:999px;padding:8px 12px;text-decoration:none}@media(max-width:760px){.twilight-page{width:min(100% - 20px,1120px);padding-top:24px}.twilight-lab{grid-template-columns:1fr}.twilight-sky{min-height:260px}.twilight-flow{grid-template-columns:1fr}.twilight-metrics{grid-template-columns:1fr}}
.course-overview-image{margin:14px 0 22px;width:min(100%,560px);border:1px solid var(--border);border-radius:16px;overflow:hidden;background:var(--surface)}.course-overview-image img{display:block;width:100%;height:auto;aspect-ratio:14/9;object-fit:cover}.course-overview-image figcaption{padding:9px 12px;color:var(--muted);font-size:.72rem;line-height:1.45}


/* WTS lesson split alignment v1 — 2026-09-23 */
@media(min-width:1024px){.twilight-lab{grid-template-columns:minmax(0,1.52fr) minmax(360px,.7fr);gap:22px;margin:30px 0}.twilight-lab>*{min-width:0;align-self:start}.twilight-controls label{gap:10px}.twilight-metrics{gap:10px;grid-auto-rows:1fr}.twilight-flow{gap:14px;grid-auto-rows:1fr}.twilight-flow>*{height:100%}}


/* v2 mobile teaching workspace — keep the result and its control in one viewport */
.twilight-controls{position:sticky;top:86px}
.twilight-controls label{font-weight:700;color:var(--text)}
.twilight-controls input[type=range]{min-height:34px;accent-color:var(--accent);touch-action:pan-x}
@media(max-width:760px){
  .twilight-page{padding-top:14px}
  .twilight-page>h1{font-size:clamp(1.55rem,8vw,2.15rem);line-height:1.08;margin:7px 0}
  .twilight-page>p{font-size:.76rem;line-height:1.5;margin-bottom:10px}
  .twilight-lab{display:flex;flex-direction:column;gap:0;margin:14px 0 18px;border:1px solid var(--line);border-radius:16px;overflow:hidden;background:var(--surface)}
  .twilight-view,.twilight-controls{width:100%;border:0;border-radius:0;background:transparent}
  .twilight-view{padding:8px 8px 0}
  .twilight-sky{min-height:clamp(190px,32vh,260px);border-radius:11px}
  .twilight-metrics{grid-template-columns:repeat(3,minmax(0,1fr));gap:5px;margin-top:6px}
  .twilight-metrics div{padding:7px 6px;border-radius:9px}
  .twilight-metrics small{font-size:.56rem;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
  .twilight-metrics strong{font-size:.68rem;line-height:1.25;margin-top:3px}
  .twilight-tip{font-size:.72rem;line-height:1.45;margin:7px 2px 4px}
  .twilight-fact{font-size:.62rem;line-height:1.42;margin:4px 2px 7px}
  .twilight-controls{position:static;padding:9px 10px 10px;border-top:1px solid var(--line)}
  .twilight-controls label{gap:5px;font-size:.68rem}
  .twilight-controls input[type=range]{margin:0}
  .twilight-flow{gap:7px}
  .twilight-copy{padding:12px;border-radius:13px}
  .twilight-copy h2{font-size:.84rem;margin:0 0 5px}
  .twilight-copy p{font-size:.7rem;line-height:1.52;margin:0}
}
@media(max-width:430px){
  .twilight-page{width:calc(100% - 16px)}
  .twilight-sky{min-height:190px}
  .twilight-metrics strong{font-size:.64rem}
}


/* v3 scene feedback — connect solar altitude to photographic consequences */
.twilight-sky{--star-visibility:.25;--ground-detail:.5}
.twilight-sun{z-index:2}
.twilight-scene-layer{position:absolute;inset:0;z-index:1;pointer-events:none;overflow:hidden;border-radius:inherit}
.twilight-stars{position:absolute;inset:0 0 26%;opacity:var(--star-visibility);transition:opacity .18s ease;background-image:radial-gradient(circle at 12% 22%,rgba(255,255,255,.95) 0 1px,transparent 1.4px),radial-gradient(circle at 24% 44%,rgba(255,255,255,.8) 0 1px,transparent 1.4px),radial-gradient(circle at 39% 16%,rgba(255,255,255,.92) 0 1.1px,transparent 1.5px),radial-gradient(circle at 52% 37%,rgba(255,255,255,.76) 0 1px,transparent 1.4px),radial-gradient(circle at 67% 19%,rgba(255,255,255,.88) 0 1px,transparent 1.4px),radial-gradient(circle at 79% 48%,rgba(255,255,255,.8) 0 1px,transparent 1.4px),radial-gradient(circle at 91% 27%,rgba(255,255,255,.95) 0 1px,transparent 1.5px),radial-gradient(circle at 18% 70%,rgba(255,255,255,.72) 0 1px,transparent 1.4px),radial-gradient(circle at 44% 63%,rgba(255,255,255,.9) 0 1px,transparent 1.5px),radial-gradient(circle at 72% 72%,rgba(255,255,255,.7) 0 1px,transparent 1.4px),radial-gradient(circle at 86% 61%,rgba(255,255,255,.84) 0 1px,transparent 1.4px)}
.twilight-foreground{position:absolute;left:-4%;right:-4%;bottom:-1px;height:40%;background:linear-gradient(to bottom,rgba(16,28,35,calc(.42 + var(--ground-detail)*.34)),rgba(3,8,12,.96));clip-path:polygon(0 58%,8% 45%,15% 51%,24% 29%,32% 50%,43% 37%,52% 61%,61% 42%,68% 48%,78% 31%,87% 52%,94% 44%,100% 57%,100% 100%,0 100%);transition:background .18s ease}
.twilight-foreground::after{content:"";position:absolute;inset:42% 0 0;opacity:var(--ground-detail);background:linear-gradient(112deg,transparent 0 22%,rgba(115,139,134,.24) 23% 25%,transparent 26% 55%,rgba(120,143,140,.18) 56% 58%,transparent 59%);transition:opacity .18s ease}
.twilight-histogram{position:absolute;right:10px;top:10px;width:122px;padding:8px 9px 7px;border:1px solid rgba(255,255,255,.18);border-radius:10px;background:rgba(3,9,18,.56);backdrop-filter:blur(6px);box-shadow:0 7px 20px rgba(0,0,0,.16)}
.twilight-histogram small{display:block;margin-bottom:5px;color:rgba(240,246,255,.82);font-size:.58rem;letter-spacing:.02em}
.twilight-histogram-bars{display:flex;align-items:flex-end;gap:2px;height:35px}
.twilight-histogram-bars i{display:block;flex:1;min-width:2px;height:18%;border-radius:2px 2px 0 0;background:rgba(245,199,111,.82);transition:height .16s ease}
.twilight-scene-readout{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:7px;margin-top:8px}
.twilight-scene-readout>div{padding:8px 10px;border:1px solid var(--line);border-radius:10px;background:rgba(4,12,22,.28)}
.twilight-scene-readout small{display:block;color:var(--muted);font-size:.62rem;line-height:1.2}
.twilight-scene-readout strong{display:block;margin-top:3px;font-size:.78rem;line-height:1.25}
.twilight-scene-readout p{grid-column:1/-1;margin:0 2px;color:var(--muted);font-size:.6rem;line-height:1.35}
@media(max-width:760px){
  .twilight-histogram{right:7px;top:7px;width:104px;padding:6px 7px}
  .twilight-histogram-bars{height:29px}
  .twilight-scene-readout{margin-top:6px;gap:5px}
  .twilight-scene-readout>div{padding:6px 7px}
  .twilight-scene-readout small{font-size:.54rem}
  .twilight-scene-readout strong{font-size:.66rem}
  .twilight-scene-readout p{font-size:.55rem}
}
@media(prefers-reduced-motion:reduce){.twilight-stars,.twilight-foreground,.twilight-histogram-bars i{transition:none}}