/* =========================================================
   AiMod — 简约高级版
   结构：tokens → base → nav → hero(scene) → statement →
         steps(scene) → video → features → library → spec →
         faq → outro → footer → motion → responsive
   ========================================================= */

:root {
  color-scheme: dark;
  --bg: #000;
  --bg-soft: #0b0b0d;
  --card: #111114;
  --line: rgba(255, 255, 255, .09);
  --line-strong: rgba(255, 255, 255, .16);
  --text: #f5f5f7;
  --muted: #86868b;
  --dim: #55555b;
  --accent: #6ff0ea;
  --ease: cubic-bezier(.22, .61, .36, 1);
  --ease-out: cubic-bezier(.16, 1, .3, 1);
  --wrap: 1180px;
  --pad: 32px;
  --nav-h: 64px;
  font-family: "SF Pro Display", "Inter", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

* { box-sizing: border-box; }
html { background: var(--bg); scroll-behavior: smooth; }
body { margin: 0; color: var(--text); background: var(--bg); line-height: 1.7; overflow-x: hidden; }
h1, h2, h3, p, figure { margin: 0; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
img, video { display: block; max-width: 100%; }
::selection { background: rgba(111, 240, 234, .28); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; border-radius: 6px; }

.wrap { width: 100%; max-width: calc(var(--wrap) + var(--pad) * 2); margin-inline: auto; padding-inline: var(--pad); }
.muted { color: var(--muted); }
.eyebrow { color: var(--muted); font-size: 13px; font-weight: 600; letter-spacing: .08em; }
.note { margin-top: 28px; color: var(--dim); font-size: 13px; }
.skip { position: absolute; z-index: 1000; left: 16px; top: -80px; padding: 8px 14px; background: #fff; color: #000; border-radius: 8px; }
.skip:focus { top: 12px; }

h2 { font-size: clamp(32px, 4.4vw, 56px); line-height: 1.12; letter-spacing: -.04em; font-weight: 700; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 48px; padding: 0 24px; border-radius: 999px; font-size: 15px; font-weight: 600;
  transition: background .3s, color .3s, border-color .3s, transform .4s var(--ease-out);
}
.btn-light { background: var(--text); color: #000; }
.btn-light:hover { background: #fff; }
.btn-ghost { color: var(--text); border: 1px solid var(--line-strong); }
.btn-ghost:hover { border-color: rgba(255, 255, 255, .4); }

/* ---------- progress + cursor ---------- */
.progress-bar {
  position: fixed; z-index: 300; left: 0; top: 0; width: 100%; height: 2px;
  background: var(--text); transform: scaleX(0); transform-origin: left; pointer-events: none;
}
.cursor {
  position: fixed; z-index: 400; left: 0; top: 0; width: 28px; height: 28px; margin: -14px 0 0 -14px;
  border-radius: 50%; border: 1px solid rgba(255, 255, 255, .5); pointer-events: none; opacity: 0;
  transition: width .35s var(--ease-out), height .35s var(--ease-out), margin .35s var(--ease-out),
              background .3s, border-color .3s, opacity .3s;
  mix-blend-mode: difference;
}
.has-cursor .cursor { opacity: 1; }
.cursor.is-hover { width: 56px; height: 56px; margin: -28px 0 0 -28px; background: #fff; border-color: #fff; }

/* ---------- nav ---------- */
.nav {
  position: fixed; z-index: 200; inset: 0 0 auto; height: var(--nav-h);
  transition: background .4s, border-color .4s; border-bottom: 1px solid transparent;
}
.nav.is-solid { background: rgba(0, 0, 0, .72); border-color: var(--line); backdrop-filter: saturate(1.6) blur(20px); -webkit-backdrop-filter: saturate(1.6) blur(20px); }
.nav-inner { height: 100%; display: flex; align-items: center; gap: 36px; }
.brand { display: inline-flex; align-items: center; gap: 9px; font-size: 17px; font-weight: 700; letter-spacing: -.02em; }
.brand img { width: 26px; height: 26px; }
.nav-links { display: flex; gap: 32px; margin-left: auto; }
.nav-links a { color: var(--muted); font-size: 13.5px; transition: color .25s; }
.nav-links a:hover { color: var(--text); }
.nav-cta { height: 34px; padding: 0 16px; display: inline-flex; align-items: center; border-radius: 999px; background: var(--text); color: #000; font-size: 13px; font-weight: 600; }
.nav-toggle { display: none; margin-left: auto; width: 40px; height: 40px; padding: 0; border: 0; background: none; cursor: pointer; }
.nav-toggle i { display: block; width: 20px; height: 1.5px; margin: 6px auto; background: currentColor; transition: transform .35s var(--ease); }
.nav-toggle[aria-expanded="true"] i:first-child { transform: translateY(3.75px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] i:last-child { transform: translateY(-3.75px) rotate(-45deg); }
.mobile-menu { display: none; }

/* =========================================================
   Scene 基础：外层撑出滚动距离，内层 sticky 固定一屏
   ========================================================= */
.scene { position: relative; }
.stage { position: sticky; top: 0; height: 100vh; height: 100svh; overflow: hidden; }

/* ---------- 1. hero ---------- */
.scene-hero { height: 280vh; }
.hero-copy {
  position: absolute; inset: 0 0 auto; padding: calc(var(--nav-h) + 10vh) var(--pad) 0;
  text-align: center; will-change: transform, opacity;
}
.hero-title { margin: 18px 0 22px; font-size: clamp(44px, 7.4vw, 104px); line-height: 1.04; letter-spacing: -.055em; font-weight: 700; }
.hero-title .line { display: block; overflow: hidden; padding-bottom: .06em; }
.hero-title .line > span { display: inline-block; transform: translateY(105%); animation: rise 1.2s var(--ease-out) forwards; }
.hero-title .line:nth-child(2) > span { animation-delay: .12s; }
.hero-sub { max-width: 620px; margin: 0 auto; color: var(--muted); font-size: clamp(15px, 1.35vw, 19px); line-height: 1.8; }
.hero-actions { display: flex; justify-content: center; gap: 12px; margin-top: 34px; }
.reveal-load { opacity: 0; transform: translateY(16px); animation: fadeUp 1s var(--ease-out) forwards; }
.eyebrow.reveal-load { animation-delay: .05s; }
.hero-sub.reveal-load { animation-delay: .35s; }
.hero-actions.reveal-load { animation-delay: .5s; }
@keyframes rise { to { transform: translateY(0); } }
@keyframes fadeUp { to { opacity: 1; transform: none; } }

.reel {
  position: absolute; left: 50%; top: 0; width: 80vw; height: 45vw; overflow: hidden;
  border-radius: 24px; background: var(--bg-soft); transform: translateX(-50%);
  box-shadow: 0 0 0 1px var(--line);
  will-change: width, height, transform, border-radius;
}
.reel .video-slot { position: absolute; inset: 0; border-radius: 0; }
.reel-caption {
  position: absolute; left: 0; right: 0; bottom: 0; padding: 0 var(--pad) 8vh; text-align: center; pointer-events: none;
  opacity: 0; transform: translateY(24px);
  background: linear-gradient(transparent, rgba(0, 0, 0, .55)); padding-top: 20vh;
}
.reel-caption span { display: block; color: rgba(255, 255, 255, .7); font-size: 14px; font-weight: 600; letter-spacing: .08em; margin-bottom: 8px; }
.reel-caption strong { font-size: clamp(30px, 4.6vw, 64px); letter-spacing: -.04em; line-height: 1.1; }
.scroll-hint {
  position: absolute; left: 50%; bottom: 26px; transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 10px;
  color: var(--dim); font-size: 11px; letter-spacing: .15em;
}
.scroll-hint span { width: 1px; height: 36px; background: linear-gradient(var(--muted), transparent); animation: hint 2s var(--ease) infinite; transform-origin: top; }
@keyframes hint { 0% { transform: scaleY(0); } 50% { transform: scaleY(1); } 100% { transform: scaleY(1); opacity: 0; } }

/* ---------- video slot（通用） ---------- */
.video-slot { position: relative; overflow: hidden; background: #0d0d10; }
.video-slot video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; opacity: 0; transition: opacity .8s var(--ease); }
.video-slot.is-ready video { opacity: 1; }
.video-slot.is-ready .video-placeholder { opacity: 0; }
.video-placeholder {
  position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 12px;
  color: var(--dim); font-size: 13px; transition: opacity .6s;
  background:
    radial-gradient(ellipse at 50% 120%, rgba(111, 240, 234, .10), transparent 60%),
    repeating-linear-gradient(135deg, rgba(255, 255, 255, .025) 0 1px, transparent 1px 14px),
    #0d0d10;
}
.video-placeholder b { color: var(--muted); font-size: 15px; font-weight: 600; }
.video-placeholder code { font-family: ui-monospace, "Cascadia Code", Consolas, monospace; font-size: 12px; padding: 3px 9px; border: 1px solid var(--line); border-radius: 6px; }
.play-mark { width: 56px; height: 56px; border-radius: 50%; border: 1px solid var(--line-strong); position: relative; }
.play-mark::after { content: ""; position: absolute; left: 22px; top: 18px; border-left: 15px solid var(--muted); border-block: 10px solid transparent; }

/* ---------- 2. statement ---------- */
.statement { padding-block: 22vh 18vh; }
.statement-text {
  max-width: 1000px; font-size: clamp(28px, 3.9vw, 52px); line-height: 1.42; letter-spacing: -.03em; font-weight: 600;
}
.statement-text .ch { color: var(--text); opacity: .16; transition: opacity .25s linear; }
.statement-text .ch.on { opacity: 1; }

/* ---------- 3. steps ---------- */
.scene-steps { height: 460vh; border-top: 1px solid var(--line); }
.steps-stage { display: flex; align-items: center; }
.steps-grid { display: grid; grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr); gap: 72px; align-items: center; }
.steps-copy h2 { margin: 14px 0 40px; font-size: clamp(30px, 3.4vw, 46px); }
.step-list { list-style: none; margin: 0; padding: 0; }
.step { display: flex; gap: 20px; padding: 16px 0; border-top: 1px solid var(--line); opacity: .32; transition: opacity .5s var(--ease); }
.step:last-child { border-bottom: 1px solid var(--line); }
.step.is-active { opacity: 1; }
.step-no { flex: none; width: 28px; padding-top: 2px; color: var(--muted); font-size: 13px; font-variant-numeric: tabular-nums; }
.step b { display: block; font-size: 17px; font-weight: 600; }
.step p { max-height: 0; overflow: hidden; color: var(--muted); font-size: 14px; line-height: 1.7; transition: max-height .6s var(--ease), margin .6s var(--ease); }
.step.is-active p { max-height: 80px; margin-top: 6px; }
.step-meter { margin-top: 26px; height: 2px; background: var(--line); border-radius: 2px; overflow: hidden; }
.step-meter i { display: block; height: 100%; background: var(--text); transform-origin: left; transform: scaleX(0); }

.device {
  position: relative; border-radius: 18px; overflow: hidden; background: #0e0e11;
  box-shadow: 0 0 0 1px var(--line-strong), 0 60px 120px -40px rgba(0, 0, 0, .9);
  will-change: transform;
}
.device-bar { display: flex; align-items: center; gap: 7px; height: 42px; padding: 0 16px; border-bottom: 1px solid var(--line); }
.device-bar i { width: 10px; height: 10px; border-radius: 50%; background: #2a2a2e; }
.device-bar span { margin-left: 10px; color: var(--dim); font-size: 12px; font-weight: 600; }
.device-body { position: relative; aspect-ratio: 16 / 11; }
.screen { position: absolute; inset: 0; padding: 26px; opacity: 0; transform: translateY(20px) scale(.98); pointer-events: none; transition: opacity .6s var(--ease), transform .8s var(--ease-out); }
.screen.is-on { opacity: 1; transform: none; }

/* screen 01 */
.screen-games { display: grid; grid-template-columns: repeat(3, 1fr); grid-template-rows: 1fr auto; gap: 14px; }
.game-tile { display: flex; flex-direction: column; gap: 3px; padding: 10px; border: 1px solid var(--line); border-radius: 12px; transition: border-color .4s, transform .6s var(--ease-out); }
.game-tile.is-pick.lit { border-color: var(--accent); transform: translateY(-4px); box-shadow: 0 0 0 3px rgba(111, 240, 234, .12); }
.gt-art { flex: 1; min-height: 60px; margin-bottom: 8px; border-radius: 8px; }
.gt-art.a { background: linear-gradient(160deg, #1d6f8c, #07263a 70%); }
.gt-art.b { background: linear-gradient(160deg, #8c6a3a, #2a1c10 70%); }
.gt-art.c { background: linear-gradient(160deg, #4f8c3a, #16290f 70%); }
.game-tile b { font-size: 13px; }
.game-tile small { color: var(--dim); font-size: 11px; }
.engine-btn { position: relative; grid-column: 1 / -1; height: 44px; border-radius: 10px; border: 1px solid var(--line-strong); overflow: hidden; display: grid; place-items: center; }
.engine-fill { position: absolute; inset: 0; background: var(--text); transform-origin: left; transform: scaleX(0); }
.engine-btn em { position: relative; font-style: normal; font-size: 13px; font-weight: 600; mix-blend-mode: difference; }

/* screen 02 */
.screen-chat { display: flex; flex-direction: column; gap: 16px; justify-content: center; }
.bubble.me { align-self: flex-end; min-height: 44px; padding: 11px 18px; border-radius: 18px 18px 4px 18px; background: var(--text); color: #000; font-size: 15px; font-weight: 600; }
.caret { display: inline-block; width: 1.5px; height: 16px; margin-left: 2px; vertical-align: -3px; background: #000; animation: blink 1s steps(2) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.bubble.ai { display: flex; gap: 10px; max-width: 86%; opacity: 0; transform: translateY(12px); transition: opacity .5s, transform .6s var(--ease-out); }
.bubble.ai.show { opacity: 1; transform: none; }
.bubble.ai img { width: 30px; height: 30px; flex: none; }
.bubble.ai > div { padding: 13px 16px; border: 1px solid var(--line); border-radius: 4px 18px 18px 18px; background: rgba(255, 255, 255, .03); }
.bubble.ai b { font-size: 12px; }
.bubble.ai p { color: var(--muted); font-size: 13px; margin: 4px 0 10px; }
.bar { height: 3px; border-radius: 3px; background: var(--line); overflow: hidden; }
.bar i { display: block; height: 100%; background: var(--accent); transform-origin: left; transform: scaleX(0); }

/* screen 03 */
.screen-game { padding: 0; }
.sea { position: absolute; inset: 0; overflow: hidden; background: linear-gradient(180deg, #0f4c66 0%, #06263a 55%, #031421 100%); }
.ray { position: absolute; top: -20%; left: 20%; width: 18%; height: 140%; background: linear-gradient(rgba(255, 255, 255, .12), transparent 70%); transform: rotate(18deg); filter: blur(8px); }
.ray.r2 { left: 58%; width: 12%; transform: rotate(24deg); opacity: .7; }
.bubbles { position: absolute; inset: 0; background-image: radial-gradient(circle, rgba(255, 255, 255, .35) 1.5px, transparent 2px); background-size: 46px 60px; opacity: .35; }
.diver { position: absolute; top: 52%; left: 8%; width: 70px; height: 26px; border-radius: 13px; background: #f5f5f7; box-shadow: 0 0 30px rgba(111, 240, 234, .5); }
.diver::before { content: ""; position: absolute; right: -4px; top: 5px; width: 14px; height: 16px; border-radius: 50%; background: #f5f5f7; }
.diver i { position: absolute; right: 100%; top: 50%; height: 2px; width: 0; margin-top: -1px; background: linear-gradient(90deg, transparent, rgba(255, 255, 255, .7)); }
.hud { position: absolute; left: 22px; top: 18px; padding: 10px 14px; border-radius: 12px; background: rgba(0, 0, 0, .35); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); }
.hud small { display: block; color: rgba(255, 255, 255, .6); font-size: 11px; }
.hud b { font-size: 28px; font-weight: 700; letter-spacing: -.03em; font-variant-numeric: tabular-nums; }
.confirm-chip { position: absolute; right: 22px; bottom: 20px; padding: 9px 10px 9px 16px; border-radius: 999px; background: rgba(0, 0, 0, .45); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); font-size: 13px; opacity: 0; transform: translateY(10px); transition: opacity .5s, transform .6s var(--ease-out); }
.confirm-chip em { margin-left: 8px; padding: 4px 12px; border-radius: 999px; background: var(--text); color: #000; font-style: normal; font-weight: 600; }
.confirm-chip.show { opacity: 1; transform: none; }

/* screen 04 */
.screen-mods { display: flex; flex-direction: column; gap: 10px; }
.mods-head { display: flex; justify-content: space-between; align-items: baseline; padding-bottom: 12px; border-bottom: 1px solid var(--line); }
.mods-head small { color: var(--dim); font-size: 12px; }
.mod { display: flex; align-items: center; gap: 14px; padding: 14px; border: 1px solid var(--line); border-radius: 12px; opacity: 0; transform: translateX(24px); transition: opacity .5s, transform .7s var(--ease-out), border-color .4s; }
.mod.show { opacity: 1; transform: none; }
.mod.saved.show { border-color: rgba(111, 240, 234, .45); }
.mod b { display: block; font-size: 14px; }
.mod small { color: var(--dim); font-size: 11.5px; }
.mi { flex: none; width: 36px; height: 36px; display: grid; place-items: center; border-radius: 10px; background: rgba(255, 255, 255, .05); color: var(--text); font-weight: 700; }
.tgl { margin-left: auto; width: 40px; height: 24px; border-radius: 12px; background: #2a2a2e; position: relative; transition: background .4s; }
.tgl::after { content: ""; position: absolute; left: 3px; top: 3px; width: 18px; height: 18px; border-radius: 50%; background: #fff; transition: transform .45s var(--ease-out); }
.tgl.on { background: var(--accent); }
.tgl.on::after { transform: translateX(16px); }
.kbd { margin-left: auto; padding: 3px 9px; border: 1px solid var(--line-strong); border-bottom-width: 2px; border-radius: 6px; color: var(--muted); font-size: 11.5px; font-weight: 600; white-space: nowrap; }

/* ---------- sections ---------- */
.section { padding-block: 140px; }
.section-head { margin-bottom: 56px; }
.section-head h2 { margin-top: 14px; }

/* 4. videos */
.video-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.video-card .video-slot { aspect-ratio: 4 / 5; border-radius: 20px; box-shadow: 0 0 0 1px var(--line); }
.video-card .video-slot video { transition: opacity .8s var(--ease), transform 1.2s var(--ease-out); }
.video-card:hover .video-slot video { transform: scale(1.04); }
.video-card figcaption { display: flex; flex-direction: column; gap: 2px; padding: 18px 4px 0; }
.video-card figcaption b { font-size: 17px; font-weight: 600; }
.video-card figcaption span { color: var(--muted); font-size: 14px; }
.video-card:nth-child(2) { margin-top: 64px; }

/* 5. features */
.feature-list { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--line); }
.feature { padding: 30px 28px 10px 0; }
.feature + .feature { padding-left: 28px; border-left: 1px solid var(--line); }
.f-no { color: var(--dim); font-size: 13px; font-variant-numeric: tabular-nums; }
.feature h3 { margin: 44px 0 10px; font-size: 20px; font-weight: 600; letter-spacing: -.02em; }
.feature p { color: var(--muted); font-size: 14.5px; }

/* 6. library */
.library { display: grid; grid-template-columns: 1fr 1fr; gap: 90px; align-items: center; border-top: 1px solid var(--line); }
.library-copy h2 { margin: 14px 0 22px; }
.library-copy p { color: var(--muted); font-size: 17px; max-width: 460px; }
.library-card { padding: 24px; border-radius: 22px; background: var(--card); box-shadow: 0 0 0 1px var(--line-strong), 0 50px 100px -40px rgba(0, 0, 0, .9); transform-style: preserve-3d; }
.tilt { transition: transform .8s var(--ease-out); }
.tilt.is-tilting { transition: transform .15s linear; }
.lc-head { display: flex; justify-content: space-between; align-items: baseline; padding-bottom: 14px; margin-bottom: 4px; border-bottom: 1px solid var(--line); }
.lc-head b { font-size: 17px; }
.lc-head small { color: var(--dim); font-size: 12px; }
.lc-row { display: flex; align-items: center; gap: 14px; padding: 16px 4px; border-bottom: 1px solid var(--line); }
.lc-row:last-child { border-bottom: 0; }
.lc-row b { display: block; font-size: 14.5px; }
.lc-row small { color: var(--dim); font-size: 12px; }
.grow { flex: 1; }
.coin { margin-left: 6px; color: var(--muted); font-weight: 500; font-variant-numeric: tabular-nums; }
.switch { margin-left: auto; flex: none; position: relative; width: 44px; height: 26px; padding: 0; border: 0; border-radius: 13px; background: #2a2a2e; cursor: pointer; transition: background .35s; }
.switch::after { content: ""; position: absolute; left: 3px; top: 3px; width: 20px; height: 20px; border-radius: 50%; background: #fff; transition: transform .45s var(--ease-out); }
.switch[aria-pressed="true"] { background: var(--accent); }
.switch[aria-pressed="true"]::after { transform: translateX(18px); }
.range { width: 100%; margin: 12px 0 0; height: 4px; border-radius: 4px; appearance: none; -webkit-appearance: none; cursor: pointer;
  background: linear-gradient(90deg, var(--text) var(--val, 66%), #2a2a2e var(--val, 66%)); }
.range::-webkit-slider-thumb { -webkit-appearance: none; width: 18px; height: 18px; border-radius: 50%; background: #fff; box-shadow: 0 2px 8px rgba(0, 0, 0, .5); }
.range::-moz-range-thumb { width: 18px; height: 18px; border: 0; border-radius: 50%; background: #fff; }

/* 7. spec */
#fit { border-top: 1px solid var(--line); }
.spec-list { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.spec { padding: 30px; border-radius: 20px; background: var(--bg-soft); box-shadow: 0 0 0 1px var(--line); }
.spec b { display: block; margin-bottom: 10px; font-size: 18px; font-weight: 600; }
.spec p { color: var(--muted); font-size: 14.5px; }

/* 8. faq */
.faq { display: grid; grid-template-columns: .8fr 1.2fr; gap: 60px; border-top: 1px solid var(--line); }
.faq-list { border-top: 1px solid var(--line); }
details { border-bottom: 1px solid var(--line); }
summary { position: relative; list-style: none; cursor: pointer; padding: 24px 44px 24px 0; font-size: 17px; font-weight: 600; }
summary::-webkit-details-marker { display: none; }
summary::before, summary::after { content: ""; position: absolute; right: 6px; top: 50%; width: 14px; height: 1.5px; background: var(--muted); transition: transform .4s var(--ease-out); }
summary::after { transform: rotate(90deg); }
details[open] summary::after { transform: rotate(0); }
details p { padding: 0 44px 24px 0; color: var(--muted); font-size: 15px; }

/* 9. outro */
.outro { padding-block: 180px 160px; text-align: center; border-top: 1px solid var(--line); overflow: hidden; }
.outro-title { font-size: clamp(38px, 6.4vw, 88px); line-height: 1.08; letter-spacing: -.05em; will-change: transform; }
.outro-inner p { max-width: 520px; margin: 28px auto 36px; color: var(--muted); font-size: 16px; }

.footer { border-top: 1px solid var(--line); }
.footer-inner { display: flex; align-items: center; gap: 28px; padding-block: 30px; color: var(--dim); font-size: 13px; }
.footer-inner .brand { margin-right: auto; color: var(--text); font-size: 15px; }
.footer-inner .brand img { width: 22px; height: 22px; }
.footer-inner a:not(.brand):hover { color: var(--text); }

/* ---------- 进场动画（滚动到时淡入） ---------- */
.js [data-reveal] { opacity: 0; transform: translateY(40px); transition: opacity 1s var(--ease-out), transform 1.2s var(--ease-out); transition-delay: var(--d, 0ms); }
.js [data-reveal].in { opacity: 1; transform: none; }
.js .library-card[data-reveal].in { transition: opacity 1s var(--ease-out), transform .8s var(--ease-out); }
.js .library-card.is-tilting { transition: transform .15s linear; }

/* ---------- responsive ---------- */
@media (hover: none), (pointer: coarse) { .cursor { display: none; } }

@media (max-width: 960px) {
  .nav-links, .nav-cta { display: none; }
  .nav-toggle { display: block; }
  .mobile-menu { position: absolute; top: var(--nav-h); left: 0; right: 0; display: flex; flex-direction: column; padding: 8px var(--pad) 20px; background: rgba(0, 0, 0, .94); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); border-bottom: 1px solid var(--line); transform: translateY(-8px); opacity: 0; visibility: hidden; transition: opacity .3s, transform .4s var(--ease-out), visibility .3s; }
  .mobile-menu.open { opacity: 1; visibility: visible; transform: none; }
  .mobile-menu a { padding: 14px 0; border-bottom: 1px solid var(--line); font-size: 17px; }
  .nav:has(.mobile-menu.open) { background: rgba(0, 0, 0, .94); }

  .steps-grid { grid-template-columns: 1fr; gap: 24px; }
  .steps-copy h2 { margin: 8px 0 16px; font-size: 26px; }
  .steps-copy .eyebrow { display: none; }
  .step { padding: 10px 0; }
  .step b { font-size: 15px; }
  .step p { font-size: 13px; }
  .step:not(.is-active) { display: none; }
  .step-meter { margin-top: 12px; }
  .device { max-width: 560px; }

  .video-grid { grid-template-columns: 1fr 1fr; }
  .video-card:nth-child(2) { margin-top: 0; }
  .video-card:nth-child(3) { grid-column: 1 / -1; }
  .video-card:nth-child(3) .video-slot { aspect-ratio: 16 / 9; }
  .feature-list { grid-template-columns: 1fr 1fr; }
  .feature:nth-child(3) { padding-left: 0; border-left: 0; }
  .feature:nth-child(n+3) { border-top: 1px solid var(--line); }
  .library, .faq { grid-template-columns: 1fr; gap: 48px; }
  .spec-list { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  :root { --pad: 18px; --nav-h: 58px; }
  .br-desk { display: none; }
  .hero-copy { padding-top: calc(var(--nav-h) + 7vh); }
  .hero-actions { flex-direction: column; align-items: center; }
  .hero-actions .btn { width: 100%; max-width: 320px; }
  .scene-hero { height: 220vh; }
  .scroll-hint { display: none; }
  .statement { padding-block: 16vh 12vh; }
  .section { padding-block: 96px; }
  .section-head { margin-bottom: 36px; }
  .screen { padding: 16px; }
  .screen-games { gap: 8px; }
  .gt-art { min-height: 36px; }
  .game-tile { padding: 7px; }
  .game-tile b { font-size: 11px; }
  .game-tile small { display: none; }
  .bubble.me { font-size: 13px; }
  .hud b { font-size: 20px; }
  .confirm-chip { font-size: 11px; right: 12px; bottom: 12px; }
  .diver { width: 48px; height: 18px; }
  .diver::before { width: 10px; height: 11px; top: 3.5px; }
  .mod { padding: 10px; }
  .video-grid { grid-template-columns: 1fr; }
  .video-card .video-slot, .video-card:nth-child(3) .video-slot { aspect-ratio: 16 / 10; }
  .feature-list { grid-template-columns: 1fr; }
  .feature, .feature + .feature { padding: 24px 0; border-left: 0; }
  .feature + .feature { border-top: 1px solid var(--line); }
  .feature h3 { margin-top: 14px; }
  .outro { padding-block: 120px; }
  .footer-inner { flex-wrap: wrap; gap: 12px 22px; }
  .footer-inner .brand { flex-basis: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
  .js [data-reveal] { opacity: 1; transform: none; }
  .cursor { display: none; }
}