/* Layout: full-bleed 16:9 stage, HUD pinned to the edges like the reference intro.
   Single deliberate dark look; per-character accents are swapped on #app by JS. */
:root {
  color-scheme: dark;
  --bg: #02050a;
  --ink: #e9eef9;
  --ink-dim: rgba(205, 216, 238, 0.62);
  --ink-faint: rgba(190, 204, 232, 0.32);
  --accent: #38d9c6;
  --code: #45f59c;
  --glow: #6ea8ff;
  --chrome-top: #ffffff;
  --chrome-mid: #9fb0d9;
  --f-display: 'Saira', 'Exo 2', 'Segoe UI', system-ui, sans-serif;
  --f-hud: 'Chakra Petch', 'Saira', 'Segoe UI', system-ui, sans-serif;
  --f-mono: 'JetBrains Mono', ui-monospace, 'Cascadia Mono', Consolas, monospace;
  --f-cn: 'PingFang SC', 'HarmonyOS Sans SC', 'Microsoft YaHei UI', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  /* one scale unit: 1% of the 16:9 frame width */
  --u: min(1vw, 1.7778vh);
  --hud-xs: max(9px, calc(var(--u) * 0.64));
  --hud-s: max(10px, calc(var(--u) * 0.72));
}

* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--f-hud);
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

.app { position: fixed; inset: 0; overflow: hidden; background: radial-gradient(120% 90% at 78% 40%, #071022 0%, var(--bg) 62%); }
.app[data-char='chatgpt'] { background: radial-gradient(120% 90% at 78% 40%, #04130f 0%, var(--bg) 62%); }
.app[data-char='claude'] { background: radial-gradient(120% 90% at 78% 40%, #160b05 0%, var(--bg) 62%); }

.layer { position: absolute; inset: 0; width: 100%; height: 100%; display: block; pointer-events: none; }
.fallback-img { object-fit: cover; object-position: 85% 35%; opacity: 0; transition: opacity 1.2s ease; }
.fallback-img.on { opacity: 1; }
.vignette {
  background:
    radial-gradient(130% 100% at 70% 45%, transparent 55%, rgba(0, 0, 0, 0.55) 100%),
    linear-gradient(90deg, rgba(2, 5, 10, 0.55) 0%, transparent 38%);
}
.scanlines {
  background: repeating-linear-gradient(0deg, rgba(255, 255, 255, 0.018) 0 1px, transparent 1px 3px);
  mix-blend-mode: overlay;
}

/* iris overlay (positioned by JS) */
.iris {
  position: absolute; left: 0; top: 0; width: 80px; height: 80px;
  pointer-events: none; opacity: 0;
  mix-blend-mode: screen;
  -webkit-mask-image: radial-gradient(circle at 50% 50%, #000 0 34%, rgba(0, 0, 0, 0.55) 40%, transparent 46%);
  mask-image: radial-gradient(circle at 50% 50%, #000 0 34%, rgba(0, 0, 0, 0.55) 40%, transparent 46%);
}
.iris canvas { width: 100%; height: 100%; display: block; }
.glint {
  position: absolute; left: 0; top: 0; width: 10px; height: 10px; pointer-events: none;
  border-radius: 50%; opacity: 0;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.95) 0 6%, var(--glow) 18%, transparent 60%);
  mix-blend-mode: screen;
}
.glint.flash { animation: glint 1.1s ease-out forwards; }
@keyframes glint {
  0% { opacity: 0; scale: 0.2; }
  18% { opacity: 1; scale: 1.25; }
  100% { opacity: 0; scale: 2.4; }
}

/* ---------------- HUD ---------------- */
.hud { position: absolute; inset: 0; pointer-events: none; transition: opacity 0.45s ease, filter 0.45s ease; }
.hud.leaving { opacity: 0; filter: blur(6px); }
.hud.reset * { transition: none !important; animation: none !important; }
.hud > * { position: absolute; margin: 0; }
.caret::after { content: '▌'; color: var(--accent); margin-left: 1px; animation: blink 0.7s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }

.fade { opacity: 0; transition: opacity 0.6s ease, transform 0.6s ease; }
.fade.on { opacity: 1; }

/* top-left brand */
.brand { left: 3.1%; top: 5.6%; display: flex; align-items: center; gap: calc(var(--u) * 0.9); }
.site-glyph { color: var(--accent); filter: drop-shadow(0 0 5px color-mix(in srgb, var(--accent) 60%, transparent)); }
.emblem { display: inline-flex; width: max(16px, calc(var(--u) * 1.5)); height: max(16px, calc(var(--u) * 1.5)); color: var(--ink); }
.emblem svg { width: 100%; height: 100%; overflow: visible; }
.brand-name { font-family: var(--f-display), var(--f-cn); font-weight: 600; font-size: max(13px, calc(var(--u) * 1.18)); letter-spacing: 0.01em; }
.brand-rule { position: relative; display: block; width: calc(var(--u) * 13.5); height: 1px; margin-left: calc(var(--u) * 1.2); }
.brand-rule i { position: absolute; inset: 0; background: linear-gradient(90deg, var(--ink-faint), rgba(230, 238, 255, 0.7)); transform-origin: left; transform: scaleX(0); transition: transform 1.1s cubic-bezier(0.2, 0.7, 0.1, 1); }
.brand-rule b { position: absolute; right: calc(var(--u) * -1.3); top: 50%; translate: 0 -52%; font-weight: 400; font-size: max(11px, calc(var(--u) * 1)); color: var(--ink-dim); opacity: 0; transition: opacity 0.4s ease 0.9s; }
.brand.on .brand-rule i { transform: scaleX(1); }
.brand.on .brand-rule b { opacity: 1; }

.brand-sub { left: 6.25%; top: 10.1%; font-size: var(--hud-xs); letter-spacing: 0.17em; line-height: 1.55; color: var(--ink-dim); }
.brand-sub span { display: block; min-height: 1.55em; }

/* left status list */
.status { left: 3.2%; top: 17.6%; list-style: none; padding: 0; font-size: var(--hud-xs); letter-spacing: 0.14em; line-height: 1.62; color: var(--ink-dim); }
.status li { min-height: 1.62em; }
.status li.done::first-letter { color: var(--ink); }
.mini-bar { width: calc(var(--u) * 3.4); height: 2px; background: rgba(160, 180, 220, 0.18); opacity: 0; transition: opacity 0.5s ease; }
.mini-bar i { display: block; height: 100%; width: 0; background: var(--accent); box-shadow: 0 0 6px var(--accent); transition: width 1.4s cubic-bezier(0.3, 0.7, 0.2, 1); }
.mini-bar.on { opacity: 1; }
.mini-bar.on i { width: 52%; }
.mini-bar.l { left: 3.2%; top: 27.6%; }
.mini-bar.r { margin-top: calc(var(--u) * 0.5); }

/* right status */
.rcol { right: 1.4%; top: 35.6%; width: max(86px, calc(var(--u) * 6.3)); }
.status-r { margin: 0; list-style: none; padding: 0; font-size: var(--hud-xs); letter-spacing: 0.14em; line-height: 1.62; color: var(--ink-dim); white-space: nowrap; }
.status-r li { min-height: 1.62em; }


/* bottom corners */
.foot { left: 3.2%; bottom: 6.2%; font-size: var(--hud-xs); letter-spacing: 0.16em; line-height: 1.55; color: var(--ink-dim); }
.foot span { display: block; min-height: 1.55em; }
.foot .arrow { position: absolute; left: calc(100% + var(--u) * 0.6); top: -0.35em; width: calc(var(--u) * 3.3); height: 1px; background: var(--ink-faint); transform-origin: left; transform: scaleX(0); transition: transform 0.8s ease 0.5s; }
.foot .arrow::after { content: ''; position: absolute; right: 0; top: -2px; border: 2.5px solid transparent; border-left: 4px solid var(--ink-dim); border-right: 0; }
.foot.on .arrow { transform: scaleX(1); }
.corner { right: 3.4%; bottom: 6.6%; display: flex; align-items: center; gap: calc(var(--u) * 0.8); color: var(--ink-dim); font-size: var(--hud-xs); letter-spacing: 0.08em; }
.slashes { color: color-mix(in srgb, var(--glow) 55%, transparent); letter-spacing: 0.06em; font-style: italic; }

/* ---------------- title block ---------------- */
.title { left: 7.8%; top: 38.6%; }
.rail { position: absolute; left: calc(var(--u) * -3.4); top: -36%; width: 1px; height: 150%; background: linear-gradient(180deg, transparent, rgba(220, 232, 255, 0.7) 30%, rgba(220, 232, 255, 0.7) 70%, transparent); transform: scaleY(0); transform-origin: top; transition: transform 0.7s ease; }
.title.rail-on .rail { transform: scaleY(1); }
.streak { position: absolute; left: calc(var(--u) * -3.4); top: 108%; width: 60%; height: 2px; border-radius: 2px; opacity: 0; background: linear-gradient(90deg, transparent, #fff 45%, var(--glow) 60%, transparent); filter: blur(0.4px); box-shadow: 0 0 14px var(--glow); }
.title.draw .streak { animation: streak 1.2s ease-out forwards; }
@keyframes streak {
  0% { opacity: 0; transform: translateX(-10%) scaleX(0.3); }
  25% { opacity: 1; }
  100% { opacity: 0; transform: translateX(120%) scaleX(1); }
}

.logo {
  position: relative; margin: 0; white-space: nowrap;
  font-family: var(--f-display); font-style: italic; font-weight: 800; font-stretch: 125%;
  font-size: calc(var(--u) * 6.1); line-height: 1; letter-spacing: 0.005em;
}
.logo-layer { display: block; }
.logo-layer:not(.logo-fill) { position: absolute; left: 0; top: 0; }
.logo-layer span { display: inline-block; }
.logo-outline span {
  color: transparent; -webkit-text-stroke: max(1px, calc(var(--u) * 0.07)) rgba(205, 222, 255, 0.85);
  opacity: 0; transform: translateX(-0.12em) skewX(-8deg); filter: blur(4px);
  transition: opacity 0.35s ease calc(var(--i) * 70ms), transform 0.5s cubic-bezier(0.2, 0.8, 0.2, 1) calc(var(--i) * 70ms), filter 0.4s ease calc(var(--i) * 70ms);
}
.title.draw .logo-outline span { opacity: 1; transform: none; filter: none; }
.title.fill .logo-outline span { opacity: 0.25; transition-delay: calc(var(--i) * 60ms + 200ms); }
.logo-fill span {
  background: linear-gradient(180deg, var(--chrome-top) 0%, #eef3ff 36%, var(--chrome-mid) 52%, #f3f6ff 66%, color-mix(in srgb, var(--chrome-mid) 70%, #fff) 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  opacity: 0; transition: opacity 0.5s ease calc(var(--i) * 60ms);
}
.title.fill .logo-fill span { opacity: 1; }
.logo-sweep {
  background: linear-gradient(105deg, transparent 0 40%, rgba(255, 255, 255, 0.95) 48%, rgba(255, 255, 255, 0.2) 54%, transparent 60% 100%);
  background-size: 300% 100%; background-position: 120% 0;
  -webkit-background-clip: text; background-clip: text; color: transparent; opacity: 0;
}
.title.shine .logo-sweep { opacity: 1; animation: sweep 5.2s ease-in-out infinite; }
@keyframes sweep {
  0% { background-position: 120% 0; }
  32%, 100% { background-position: -20% 0; }
}
.logo-glow { color: var(--glow); filter: blur(calc(var(--u) * 1.1)); opacity: 0; transition: opacity 1s ease; }
.title.fill .logo-glow { opacity: 0.5; }

.orbit { position: absolute; left: -11.6%; top: -92%; width: 116.5%; height: 269%; overflow: visible; pointer-events: none; }
.orbit path { fill: none; stroke: url(#orbitGrad); stroke-width: 1.2; vector-effect: non-scaling-stroke; }
.orbit .comet { fill: #fff; filter: url(#cometGlow); opacity: 0; }
.title.orbit-on .orbit .comet { opacity: 1; }

.spark { position: absolute; left: calc(100% + var(--u) * 0.5); top: 22%; width: calc(var(--u) * 1.6); height: calc(var(--u) * 1.6); opacity: 0; transform: scale(0.2) rotate(-40deg); transition: opacity 0.4s ease, transform 0.7s cubic-bezier(0.2, 1.4, 0.4, 1); color: #fff; filter: drop-shadow(0 0 6px var(--glow)); }
.title.fill .spark { opacity: 1; transform: none; animation: twinkle 2.6s ease-in-out 1s infinite; }
@keyframes twinkle { 50% { opacity: 0.55; scale: 0.8; } }

.tag-cn {
  position: absolute; left: 13.5%; top: calc(100% + var(--u) * 1.9); white-space: nowrap;
  display: flex; align-items: center; gap: calc(var(--u) * 1.4);
  font-family: var(--f-cn); font-weight: 500; font-size: max(13px, calc(var(--u) * 1.42)); letter-spacing: 0.3em; color: var(--ink);
  text-shadow: 0 0 12px color-mix(in srgb, var(--glow) 55%, transparent);
}
.tag-cn .slashes { font-family: var(--f-hud); font-size: 0.6em; letter-spacing: 0.12em; }
.tag-cn em { font-style: normal; display: inline-block; opacity: 0; transform: translateY(0.35em); filter: blur(5px); transition: opacity 0.45s ease calc(var(--i) * 45ms), transform 0.45s ease calc(var(--i) * 45ms), filter 0.45s ease calc(var(--i) * 45ms); }
.tag-cn .slashes { opacity: 0; transition: opacity 0.4s ease; }
.tag-cn.on em, .tag-cn.on .slashes { opacity: 1; transform: none; filter: none; }
.tag-en {
  position: absolute; left: 21.6%; top: calc(100% + var(--u) * 5.1); white-space: nowrap;
  font-size: max(8.5px, calc(var(--u) * 0.66)); letter-spacing: 1.1em; color: var(--ink-dim); opacity: 0;
  transition: opacity 0.8s ease, letter-spacing 1.4s cubic-bezier(0.2, 0.7, 0.1, 1);
}
.tag-en.on { opacity: 1; letter-spacing: 0.52em; }

/* terminal */
.term { left: 8.1%; top: 64.2%; font-family: var(--f-mono); font-size: max(9.5px, calc(var(--u) * 0.68)); line-height: 1.75; color: var(--code); text-shadow: 0 0 8px color-mix(in srgb, var(--code) 50%, transparent); white-space: pre; }
.term div { min-height: 1.75em; }
.term .cursor { display: inline-block; width: 0.55em; height: 1em; margin-left: 0.35em; vertical-align: -0.12em; background: var(--code); animation: blink 0.9s steps(1) infinite; }

/* ---------------- pager / controls ---------------- */
.controls {
  position: absolute; left: 50%; bottom: 3.6%; translate: -50% 0; z-index: 5;
  display: flex; align-items: center; gap: calc(var(--u) * 1.4); pointer-events: auto;
  padding-bottom: env(safe-area-inset-bottom, 0px);
}
.controls button { font-family: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
.controls button:focus-visible { outline: 1px solid var(--accent); outline-offset: 4px; }
.arrow-btn { width: 30px; height: 30px; display: grid; place-items: center; color: var(--ink-dim); border: 1px solid rgba(200, 215, 245, 0.18) !important; transition: color 0.2s, border-color 0.2s; }
.arrow-btn:hover { color: var(--ink); border-color: var(--accent) !important; }
.arrow-btn svg { width: 12px; height: 12px; }
.pages { display: flex; gap: calc(var(--u) * 1.6); }
.page { display: grid; gap: 6px; min-width: max(84px, calc(var(--u) * 7.5)); text-align: left; color: var(--ink-faint); font-size: var(--hud-xs); letter-spacing: 0.18em; transition: color 0.3s; }
.page b { font-weight: 600; color: inherit; margin-right: 0.6em; }
.page .bar { display: block; height: 1px; background: rgba(200, 215, 245, 0.16); overflow: hidden; }
.page .bar i { display: block; height: 100%; width: 100%; background: var(--accent); transform-origin: left; transform: scaleX(0); box-shadow: 0 0 6px var(--accent); }
.page:hover { color: var(--ink-dim); }
.page[aria-current='true'] { color: var(--ink); }
.page.seen .bar i { transform: scaleX(1); opacity: 0.35; }
.sound { font-size: var(--hud-xs); letter-spacing: 0.18em; color: var(--ink-faint) !important; padding: 6px 0 !important; transition: color 0.2s; }
.sound:hover, .sound[aria-pressed='true'] { color: var(--ink) !important; }
.sound[aria-pressed='true'] .state { color: var(--accent); }


/* ---------------- entry page: nav, call to action, endpoint ---------------- */
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.nav {
  position: absolute; right: 3.4%; top: 5%; z-index: 6; margin: 0;
  display: flex; align-items: center; gap: calc(var(--u) * 2);
  font-size: var(--hud-s); letter-spacing: 0.12em;
  opacity: 0; transition: opacity 0.8s ease 0.4s;
}
.ready .nav { opacity: 1; }
.nav a { color: var(--ink-dim); text-decoration: none; transition: color 0.2s; font-family: var(--f-hud), var(--f-cn); }
.nav a:hover { color: var(--ink); }
.nav a:focus-visible, .dock a:focus-visible, .dock button:focus-visible { outline: 1px solid var(--accent); outline-offset: 4px; }
.nav .nav-btn {
  color: var(--ink); padding: 0.55em 1.25em; border: 1px solid color-mix(in srgb, var(--accent) 55%, transparent);
  clip-path: polygon(8px 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%, 0 8px);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
}
.nav .nav-btn:hover { background: color-mix(in srgb, var(--accent) 22%, transparent); }

.dock {
  position: absolute; left: 8.1%; top: 73%; z-index: 6;
  display: grid; gap: calc(var(--u) * 1.1); justify-items: start;
  opacity: 0; transform: translateY(10px); pointer-events: none;
  transition: opacity 0.8s ease, transform 0.8s cubic-bezier(0.2, 0.7, 0.1, 1);
}
.docked .dock { opacity: 1; transform: none; pointer-events: auto; }
.cta { display: flex; gap: calc(var(--u) * 1); flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 0.6em; text-decoration: none; white-space: nowrap;
  font-family: var(--f-hud), var(--f-cn); font-weight: 600; letter-spacing: 0.08em;
  font-size: max(13px, calc(var(--u) * 0.86)); padding: 0.85em 1.5em;
  clip-path: polygon(10px 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%, 0 10px);
  transition: background 0.2s, color 0.2s, box-shadow 0.2s, transform 0.2s;
}
.btn.primary { color: #03070d; background: linear-gradient(100deg, color-mix(in srgb, var(--accent) 92%, #fff), var(--accent)); box-shadow: 0 0 24px color-mix(in srgb, var(--accent) 35%, transparent); }
.btn.primary:hover { transform: translateY(-1px); box-shadow: 0 0 34px color-mix(in srgb, var(--accent) 55%, transparent); }
.btn.ghost { color: var(--ink); background: rgba(8, 14, 26, 0.55); box-shadow: inset 0 0 0 1px rgba(200, 215, 245, 0.22); }
.btn.ghost:hover { box-shadow: inset 0 0 0 1px var(--accent); }
.btn .count { color: var(--accent); }
.endpoint {
  display: inline-flex; align-items: center; gap: calc(var(--u) * 0.9);
  padding: 0.55em 0.6em 0.55em 0.9em; border: 1px solid rgba(200, 215, 245, 0.16);
  background: rgba(3, 7, 14, 0.62); backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px);
  font-size: max(11px, calc(var(--u) * 0.72));
}
.ep-label { font-size: 0.78em; letter-spacing: 0.2em; color: var(--ink-faint); }
.endpoint code { font-family: var(--f-mono); color: var(--code); letter-spacing: 0.02em; user-select: all; }
.endpoint button {
  font: inherit; font-size: 0.85em; letter-spacing: 0.1em; color: var(--ink-dim); cursor: pointer;
  background: rgba(200, 215, 245, 0.08); border: 0; padding: 0.35em 0.8em; transition: color 0.2s, background 0.2s;
}
.endpoint button:hover { color: var(--ink); background: color-mix(in srgb, var(--accent) 22%, transparent); }
.note { position: absolute; left: 3.2%; bottom: 2.4%; margin: 0; font-size: 10px; letter-spacing: 0.08em; color: var(--ink-faint); font-family: var(--f-cn); }

/* ---------------- loader ---------------- */
.loader { position: absolute; inset: 0; z-index: 10; display: grid; place-content: center; gap: 12px; background: var(--bg); transition: opacity 0.8s ease, visibility 0.8s; font-size: 11px; letter-spacing: 0.3em; color: var(--ink-dim); text-align: center; }
.loader .lbar { width: 220px; height: 1px; background: rgba(200, 215, 245, 0.15); }
.loader .lbar i { display: block; height: 100%; width: 0; background: var(--accent); box-shadow: 0 0 8px var(--accent); transition: width 0.3s ease; }
.loader.done { opacity: 0; visibility: hidden; }
.loader .err { color: #ff8a7a; letter-spacing: 0.08em; max-width: 60ch; }

/* ---------------- narrow / portrait screens ---------------- */
@media (max-aspect-ratio: 1/1), (max-width: 760px) {
  :root { --u: 1.9vw; --hud-xs: 9px; --hud-s: 11px; }
  .vignette { background: linear-gradient(180deg, rgba(2, 5, 10, 0.45) 0%, transparent 16%, transparent 42%, rgba(2, 5, 10, 0.6) 62%, rgba(2, 5, 10, 0.8) 100%); }
  .status, .rcol, .mini-bar, .foot, .corner, .brand-rule, .term, .note { display: none; }
  .brand { left: 16px; top: calc(16px + env(safe-area-inset-top, 0px)); }
  .brand-sub { left: 16px; top: calc(44px + env(safe-area-inset-top, 0px)); }
  .nav { right: 16px; top: calc(12px + env(safe-area-inset-top, 0px)); gap: 14px; }
  .nav a:nth-child(3) { display: none; }
  .title { left: 16px; right: auto; top: auto; bottom: calc(232px + env(safe-area-inset-bottom, 0px)); }
  .logo { font-size: min(13.5vw, 64px); }
  .rail { display: none; }
  .tag-cn { left: 2px; font-size: 14px; letter-spacing: 0.22em; top: calc(100% + 16px); }
  .tag-en { left: 4px; top: calc(100% + 44px); font-size: 8.5px; }
  .tag-en.on { letter-spacing: 0.38em; }
  .dock { left: 16px; right: 16px; top: auto; bottom: calc(64px + env(safe-area-inset-bottom, 0px)); gap: 10px; justify-items: stretch; }
  .cta { flex-wrap: nowrap; gap: 8px; }
  .cta .btn { flex: 1; justify-content: center; font-size: 13px; padding: 0.9em 0.6em; letter-spacing: 0.02em; }
  .endpoint { justify-content: space-between; font-size: 11px; }
  .endpoint code { overflow: hidden; text-overflow: ellipsis; min-width: 0; }
  .controls { bottom: calc(18px + env(safe-area-inset-bottom, 0px)); gap: 10px; width: calc(100% - 32px); justify-content: space-between; padding-bottom: 0; }
  .pages { gap: 10px; flex: 1; }
  .page { min-width: 0; flex: 1; }
  .page .name { display: none; }
  .arrow-btn { display: none !important; }
}

@media (prefers-reduced-motion: reduce) {
  .logo-sweep, .spark, .caret::after, .term .cursor { animation: none !important; }
}