/* Reset, typography, shared components (nav, buttons, tags, marks, loader). */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
html.has-lenis, html.has-lenis body { height: auto; }
.lenis.lenis-smooth { scroll-behavior: auto !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-weight: 300;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  transition: background-color 0.6s var(--ease-in-out), color 0.6s var(--ease-in-out);
}
h1, h2, h3, p, ol, ul, figure { margin: 0; }
ol, ul { padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
button, input, textarea { font: inherit; color: inherit; }
button { cursor: pointer; background: none; border: 0; padding: 0; }
::selection { background: var(--ink); color: var(--bg); }
:focus-visible { outline: 1.5px solid var(--amber); outline-offset: 3px; }

.mono { font-family: var(--mono); font-size: 11px; letter-spacing: 0.06em; font-weight: 400; }
.kicker {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--muted); display: flex; align-items: center; gap: 10px;
}
.kicker::before { content: ""; width: 18px; height: 1px; background: currentColor; }
html[data-lang="zh"] .kicker { letter-spacing: 0.2em; }

/* ── Marks ─────────────────────────────────────────────── */
.mark { display: block; overflow: visible; }
.mark .mark-a { fill: var(--ink); }
.mark .mark-b { fill: var(--mid); }
.mark .mark-i { fill: var(--paper); }
.mark--line .mark-a, .mark--line .mark-b { fill: none; stroke: currentColor; stroke-width: 1.2; vector-effect: non-scaling-stroke; }

/* ── Grain overlay ─────────────────────────────────────── */
.grain {
  position: fixed; inset: -8%; z-index: 90; pointer-events: none; opacity: 0.06; will-change: transform;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0  0 0 0 0 0  0 0 0 0 0  0 0 0 .9 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
  animation: grain 1.2s steps(6) infinite;
}
@keyframes grain {
  0% { transform: translate(0, 0); } 20% { transform: translate(-3%, 2%); } 40% { transform: translate(2%, -3%); }
  60% { transform: translate(-2%, -1%); } 80% { transform: translate(3%, 3%); } 100% { transform: translate(0, 0); }
}

/* ── Loader ────────────────────────────────────────────── */
.loader {
  position: fixed; inset: 0; z-index: 100; display: grid; place-items: center; background: var(--bg);
  transition: opacity 0.7s var(--ease-in-out) 0.35s, visibility 0s linear 1.05s;
}
.loader-mark { width: 88px; }
.loader-mark .mark-a { animation: plane-a 0.9s var(--ease-out) both; }
.loader-mark .mark-b, .loader-mark .mark-i { animation: plane-b 0.9s var(--ease-out) both; }
@keyframes plane-a { from { transform: translate(-26px, -14px); opacity: 0; } }
@keyframes plane-b { from { transform: translate(26px, 14px); opacity: 0; } }
body.is-loaded .loader { opacity: 0; visibility: hidden; }
body.is-loaded .loader-mark { transform: scale(0.9); transition: transform 0.8s var(--ease-out); }

/* ── Navigation ────────────────────────────────────────── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50; height: var(--nav-h);
  display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 0 var(--gutter);
  transition: transform 0.6s var(--ease-out), background-color 0.4s, color 0.6s var(--ease-in-out), border-color 0.4s;
  border-bottom: 1px solid transparent;
}
.nav.is-scrolled { background: color-mix(in srgb, var(--bg) 82%, transparent); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); border-color: var(--line); }
/* Over the live story canvas a backdrop blur would be re-computed every frame — skip it. */
body.in-story .nav.is-scrolled { background: transparent; backdrop-filter: none; -webkit-backdrop-filter: none; border-color: transparent; }
.nav.is-hidden { transform: translateY(-100%); }
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark { width: 30px; }
.brand-zh { font-family: var(--font-cjk); font-size: 18px; letter-spacing: 0.08em; font-weight: 300; }
.brand-en { font-family: var(--font-latin); font-size: 11px; letter-spacing: 0.32em; font-weight: 400; padding-top: 2px; }
.nav-links { display: flex; gap: clamp(18px, 2.5vw, 36px); font-size: 14px; }
.nav-links a { position: relative; padding: 4px 0; }
.nav-links a::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 1px; background: currentColor;
  transform: scaleX(0); transform-origin: right; transition: transform 0.5s var(--ease-out);
}
.nav-links a:hover::after { transform: scaleX(1); transform-origin: left; }
.nav-right { display: flex; align-items: center; gap: 18px; }
.lang { display: flex; gap: 2px; font-family: var(--mono); font-size: 11px; }
.lang button { padding: 6px 8px; color: var(--muted); border-radius: 99px; transition: color 0.3s, background-color 0.3s; }
.lang button[aria-pressed="true"] { color: var(--ink); background: color-mix(in srgb, var(--ink) 8%, transparent); }

/* ── Buttons ───────────────────────────────────────────── */
.btn {
  position: relative; display: inline-flex; align-items: center; gap: 12px; overflow: hidden;
  padding: 15px 26px; border-radius: 99px; background: var(--ink); color: var(--bg);
  font-size: 15px; font-weight: 400; letter-spacing: 0.02em; isolation: isolate;
  transition: transform 0.5s var(--ease-out), color 0.5s var(--ease-out);
}
.btn::before {
  content: ""; position: absolute; inset: 0; z-index: -1; background: var(--amber);
  transform: translateY(101%); border-radius: inherit; transition: transform 0.55s var(--ease-out);
}
.btn::after { content: "→"; font-family: var(--mono); transition: transform 0.5s var(--ease-out); }
.btn:hover::before { transform: translateY(0); }
.btn:hover::after { transform: translateX(4px); }
.btn--small { padding: 10px 18px; font-size: 13px; }
.btn--small::after { content: none; }
.btn--light { background: var(--on-dark); color: var(--dark); }

/* ── Tags ──────────────────────────────────────────────── */
.tags { display: flex; flex-wrap: wrap; gap: 8px; }
.tag {
  font-size: 12px; padding: 5px 12px; border: 1px solid var(--line); border-radius: 99px; color: var(--ink-2);
  transition: border-color 0.6s, color 0.6s;
}

/* ── Reveal helper ─────────────────────────────────────── */
[data-reveal] { opacity: 0; transform: translateY(28px); transition: opacity 1s var(--ease-out), transform 1.2s var(--ease-out); }
[data-reveal].is-in { opacity: 1; transform: none; }

/* ── Dark stage (studio lights off during the shoot) ───── */
body.is-stage-dark { background: var(--dark); color: var(--on-dark); }
body.is-stage-dark .nav { color: var(--on-dark); }
body.is-stage-dark .lang button[aria-pressed="true"] { color: var(--on-dark); background: rgba(255, 255, 255, 0.1); }
body.is-stage-dark .btn--small { background: var(--on-dark); color: var(--dark); }
body.is-stage-dark .brand .mark-a { fill: var(--on-dark); }
body.is-stage-dark .brand .mark-i { fill: var(--dark-2); }
body.is-stage-dark .tag { border-color: var(--line-dark); color: var(--on-dark); }
body.is-stage-dark .kicker, body.is-stage-dark .caption-no { color: var(--on-dark-muted); }
body.is-stage-dark .grain { opacity: 0.03; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition-duration: 0.01ms !important; }
  [data-reveal] { opacity: 1; transform: none; }
}