/* ============================================================
   AIDC // DECISION — immersive landing (/landing)
   Follows the site theme system (theme.js + [data-theme]):
   tokens mirror site.css — dark = Geist dark + signal orange,
   light (site default) = Geist light + darker signal.
   Signature: the slash-particle decision core (landing.js).
   ============================================================ */

:root {
  --bg: #0a0a0a;
  --ink: #ededed;
  --ink-strong: #ffffff;
  --mut: #a1a1a1;
  --mut-2: #7d7d7d;
  --line: rgba(255, 255, 255, 0.14);
  --line-soft: rgba(255, 255, 255, 0.07);
  --signal: #ff4d00;
  --signal-hover: #ff6b2e;
  /* atmosphere (theme-dependent alphas can't be derived from --bg) */
  --halo: rgba(10, 10, 10, 0.85);
  --edge: rgba(10, 10, 10, 0.72);
  --pool-1: rgba(10, 10, 10, 0.92);
  --pool-2: rgba(10, 10, 10, 0.6);
  --pill-bg: rgba(10, 10, 10, 0.55);
  --font-display: "Archivo", "PingFang SC", "Hiragino Sans", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;
  --pad: clamp(20px, 5vw, 72px);
}

[data-theme="light"] {
  --bg: #ffffff;
  --ink: #333333;
  --ink-strong: #171717;
  --mut: #666666;
  --mut-2: #8f8f8f;
  --line: rgba(0, 0, 0, 0.12);
  --line-soft: rgba(0, 0, 0, 0.06);
  --signal: #e34400;
  --signal-hover: #ff4d00;
  --halo: rgba(255, 255, 255, 0.9);
  --edge: rgba(255, 255, 255, 0.78);
  --pool-1: rgba(255, 255, 255, 0.94);
  --pool-2: rgba(255, 255, 255, 0.66);
  --pill-bg: rgba(255, 255, 255, 0.6);
}

*, *::before, *::after { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
::selection { background: rgba(255, 77, 0, 0.25); }
a { color: inherit; text-decoration: none; }
a:focus-visible, button:focus-visible {
  outline: none;
  box-shadow: 0 0 0 2px var(--bg), 0 0 0 4px #006bff;
  border-radius: 6px;
}

/* ---------- loader ---------- */
.loader {
  position: fixed; inset: 0; z-index: 60;
  background: var(--bg);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  transition: opacity 0.7s ease, visibility 0.7s;
}
.loader.done { opacity: 0; visibility: hidden; }
.loader-mark {
  color: var(--signal);
  font-size: 2rem; font-weight: 600;
  letter-spacing: 0.1em;
  animation: pulse 1.2s ease-in-out infinite;
}
.loader-pct { color: var(--mut); font-size: 0.8rem; letter-spacing: 0.25em; }
.loader-pct::after { content: "%"; margin-left: 0.15em; }
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.35; } }

/* ---------- stage ---------- */
#stage {
  position: fixed; inset: 0; z-index: 0;
  width: 100%; height: 100%;
  display: block;
}
.vignette {
  position: fixed; inset: 0; z-index: 2; pointer-events: none;
  background: radial-gradient(ellipse 72% 64% at 50% 48%, transparent 52%, var(--edge) 100%);
}

/* ---------- HUD frame ---------- */
.hud { position: fixed; inset: 0; z-index: 5; pointer-events: none; }
.hud .c {
  position: absolute; width: 14px; height: 14px;
  border: 1px solid var(--line);
}
.hud .tl { top: 14px; left: 14px; border-right: 0; border-bottom: 0; }
.hud .tr { top: 14px; right: 14px; border-left: 0; border-bottom: 0; }
.hud .bl { bottom: 14px; left: 14px; border-right: 0; border-top: 0; }
.hud .br { bottom: 14px; right: 14px; border-left: 0; border-top: 0; }
.hud-rail {
  position: absolute; right: 26px; top: 50%;
  transform: translateY(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 0.55rem;
  font-family: var(--font-mono); font-size: 0.62rem; letter-spacing: 0.18em;
  color: var(--mut-2);
}
.hud-idx { color: var(--signal); font-weight: 600; }
.hud-sep { transform: rotate(90deg); }
.hud-label {
  writing-mode: vertical-rl;
  letter-spacing: 0.34em;
  color: var(--mut);
  border-left: 1px solid var(--line-soft);
  padding-left: 0.55rem; margin-top: 0.4rem;
}

/* ---------- top chrome ---------- */
.top {
  position: fixed; top: 0; left: 0; right: 0; z-index: 40;
  display: flex; align-items: center; justify-content: space-between;
  padding: 22px var(--pad);
}
.wordmark {
  font-family: var(--font-mono); font-weight: 600;
  font-size: 1rem; letter-spacing: 0.14em; color: var(--ink-strong);
}
.wordmark span { color: var(--signal); margin-right: 0.18em; }
.pill {
  display: flex; align-items: center; gap: 0.2rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.3rem 0.35rem;
  background: var(--pill-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.12em;
}
.pill a { padding: 0.42rem 0.95rem; border-radius: 999px; color: var(--mut); transition: color 0.15s; }
.pill a:hover { color: var(--ink-strong); }
.pill .cta { background: var(--signal); color: #ffffff; font-weight: 600; }
[data-theme="dark"] .pill .cta { color: #0b0b0c; }
.pill .cta:hover { background: var(--signal-hover); }
.pill-theme {
  display: inline-flex; align-items: center; justify-content: center;
  width: 32px; height: 32px;
  border: 0; border-radius: 999px;
  background: transparent; color: var(--mut);
  cursor: pointer;
  transition: color 0.15s;
}
.pill-theme:hover { color: var(--ink-strong); }
.pill-theme svg { width: 15px; height: 15px; }
[data-theme="light"] .pill-theme .i-sun { display: none; }
[data-theme="dark"] .pill-theme .i-moon { display: none; }

/* ---------- panels ---------- */
main { position: relative; z-index: 10; }
.panel {
  min-height: 125vh;
  display: flex; flex-direction: column; justify-content: center;
  padding: 0 var(--pad);
  position: relative;
}
.panel.hero, .panel.last { min-height: 100vh; }
.block { max-width: 32rem; }
.hero .block { max-width: 46rem; }
.block.wide { max-width: 44rem; }
.block.left { margin-right: auto; }
.block.right { margin-left: auto; text-align: left; }
.block.center { margin: 0 auto; text-align: center; }

.eyebrow {
  font-family: var(--font-mono); font-size: 0.7rem; font-weight: 500;
  letter-spacing: 0.3em; color: var(--mut);
  margin: 0 0 1.4rem;
  text-transform: uppercase;
}
.eyebrow b, .eyebrow .n { color: var(--signal); font-weight: 600; }

h1 {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 8vw, 6.2rem);
  font-weight: 800; letter-spacing: 0.02em; line-height: 1.08;
  color: var(--ink-strong);
  margin: 0 0 1.1rem;
  text-shadow: 0 0 14px var(--halo), 0 0 28px var(--halo), 0 2px 40px var(--halo);
}
h2 {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4.4vw, 3.2rem);
  font-weight: 700; letter-spacing: 0.01em; line-height: 1.22;
  color: var(--ink-strong);
  margin: 0 0 1.4rem;
  text-shadow: 0 0 12px var(--halo), 0 0 24px var(--halo), 0 2px 34px var(--halo);
}
.ghost {
  font-family: var(--font-mono); font-size: 0.78rem;
  letter-spacing: 0.52em; color: var(--mut-2);
  margin: 0 0 2rem;
}
.lede {
  font-size: clamp(1rem, 1.6vw, 1.18rem); color: var(--ink); margin: 0;
  text-shadow: 0 0 8px var(--halo), 0 0 16px var(--halo), 0 1px 26px var(--halo);
}
.body {
  font-size: 1rem; color: var(--mut); margin: 0; max-width: 30rem;
  text-shadow: 0 0 8px var(--halo), 0 0 16px var(--halo), 0 1px 26px var(--halo);
}
.block.center .body { margin: 0 auto; }

/* scroll hint */
.scroll-hint {
  position: absolute; bottom: 40px; left: 50%;
  transform: translateX(-50%);
  font-family: var(--font-mono); font-size: 0.64rem; letter-spacing: 0.3em;
  color: var(--mut-2);
  display: flex; align-items: center; gap: 0.8rem;
}
.scroll-hint b { color: var(--signal); }
.scroll-hint .tick {
  width: 1px; height: 34px; background: var(--line);
  position: relative; overflow: hidden;
}
.scroll-hint .tick::after {
  content: ""; position: absolute; left: 0; top: -50%;
  width: 100%; height: 50%; background: var(--signal);
  animation: drip 1.8s cubic-bezier(0.6, 0, 0.4, 1) infinite;
}
@keyframes drip { to { top: 110%; } }

/* layers list (scene 03) */
.layers { list-style: none; margin: 2.4rem 0 0; padding: 0; }
.layers li {
  display: grid;
  grid-template-columns: 7.5rem 7rem 1fr;
  gap: 1.4rem; align-items: baseline;
  padding: 1.15rem 0;
  border-top: 1px solid var(--line-soft);
}
.layers li:last-child { border-bottom: 1px solid var(--line-soft); }
.layers .tag {
  font-family: var(--font-mono); font-size: 0.7rem; font-weight: 600;
  letter-spacing: 0.24em; color: var(--mut);
}
.layers .tag.hot { color: var(--signal); }
.layers .name { font-weight: 700; color: var(--ink-strong); font-size: 1.05rem; }
.layers .desc { color: var(--mut); font-size: 0.92rem; text-shadow: 0 1px 14px var(--halo); }

/* trace readout (scene 04) */
.trace {
  margin-top: 2.2rem;
  border: 1px solid var(--line-soft);
  border-radius: 6px;
  font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.14em;
  background: var(--pill-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.trace .tr {
  display: grid; grid-template-columns: 5.4rem 1fr auto;
  gap: 1rem; padding: 0.68rem 1rem;
}
.trace .tr + .tr { border-top: 1px solid var(--line-soft); }
.trace .k { color: var(--mut-2); }
.trace .v { color: var(--ink); }
.trace .s { color: var(--signal); }

/* soft pool behind the closing text so it floats on the mark */
.panel.last .block { position: relative; }
.panel.last .block::before {
  content: "";
  position: absolute; inset: -24% -34%;
  background: radial-gradient(closest-side, var(--pool-1), var(--pool-2) 58%, transparent);
  z-index: -1;
}

/* buttons */
.btns { display: flex; gap: 0.8rem; justify-content: center; margin-top: 2.2rem; flex-wrap: wrap; }
.btn {
  font-family: var(--font-mono); font-size: 0.78rem; font-weight: 600;
  letter-spacing: 0.14em;
  padding: 0.95rem 1.9rem;
  border: 1px solid var(--line); border-radius: 999px;
  color: var(--ink);
  transition: border-color 0.2s, color 0.2s, background 0.2s, transform 0.2s;
}
.btn:hover { border-color: var(--ink-strong); color: var(--ink-strong); transform: translateY(-1px); }
.btn.primary { background: var(--signal); border-color: var(--signal); color: #ffffff; }
[data-theme="dark"] .btn.primary { color: #0b0b0c; }
.btn.primary:hover { background: var(--signal-hover); border-color: var(--signal-hover); }
.btn .arr { display: inline-block; transition: transform 0.2s; }
.btn:hover .arr { transform: translateX(3px); }

/* footer */
.foot {
  position: absolute; bottom: 26px; left: var(--pad); right: var(--pad);
  display: flex; justify-content: space-between;
  font-family: var(--font-mono); font-size: 0.6rem; letter-spacing: 0.26em;
  color: var(--mut-2);
}

/* ---------- reveals ---------- */
.reveal {
  opacity: 0; transform: translateY(26px);
  transition: opacity 0.9s ease, transform 0.9s cubic-bezier(0.16, 1, 0.3, 1);
}
.reveal.d1 { transition-delay: 0.08s; }
.reveal.d2 { transition-delay: 0.16s; }
.reveal.d3 { transition-delay: 0.26s; }
.reveal.d4 { transition-delay: 0.36s; }
.reveal.in { opacity: 1; transform: none; }

/* ---------- responsive ---------- */
@media (max-width: 720px) {
  .panel { min-height: 110vh; }
  .hud-rail { display: none; }
  .layers li { grid-template-columns: 1fr; gap: 0.25rem; }
  .trace .tr { grid-template-columns: 4.6rem 1fr; }
  .trace .s { display: none; }
  .bw { display: none; }
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .scroll-hint .tick::after, .loader-mark { animation: none; }
}