/* ============================================================================
   styles.css — 设计系统 + 全部视觉效果
   ----------------------------------------------------------------------------
   结构：1 token  2 基础  3 装饰层  4 顶栏  5 跳转轨道  6 头图舞台
        7 滚动大字  8 章节外壳  9 图文分栏  10 场景网格  11 封面 CTA
        12 折叠面板  13 页脚  14 灯箱  15 响应式  16 无障碍/降级
   ========================================================================== */

/* ---------------------------------------------------------------- 1 token */
:root {
  /* 色板：曜石黑 + 骨白 + 余烬橙，唯一的强调色只给「动作」和「进度」 */
  --ink: #07080a;
  --ink-soft: #0a0c10;
  --ink-card: #0d1014;
  --bone: #e9e5dd;
  --bone-70: rgba(233, 229, 221, .70);
  --bone-45: rgba(233, 229, 221, .45);
  --bone-25: rgba(233, 229, 221, .25);
  --line: rgba(233, 229, 221, .13);
  --line-2: rgba(233, 229, 221, .26);
  --ember: #ff5a1f;
  --ember-2: #ff9a5e;
  --mist: #8fa6b8;

  /* 字体：全部本机字体，零外链，离线可用 */
  --font-display: "Bahnschrift", "DIN Alternate", "HarmonyOS Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Segoe UI Variable Text", "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "Cascadia Mono", "Cascadia Code", ui-monospace, Consolas, "Courier New", monospace;

  --pad: clamp(18px, 4.2vw, 68px);
  --maxw: 1480px;
  --ease: cubic-bezier(.22, .61, .36, 1);
  --ease-out: cubic-bezier(.16, .84, .3, 1);
}

/* ---------------------------------------------------------------- 2 基础 */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scrollbar-color: rgba(233, 229, 221, .22) transparent;
  -webkit-tap-highlight-color: transparent;   /* 手机点按不再有灰色块 */
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--bone);
  font-family: var(--font-body);
  font-size: clamp(15px, 1.02vw, 17px);
  line-height: 1.62;
  letter-spacing: .002em;
  overflow-x: clip;                 /* 用 clip 而不是 hidden，避免破坏 sticky */
  overscroll-behavior-y: contain;   /* 防 iOS 橡皮筋把整页拽动 */
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, p, figure, ul, ol { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, video, canvas, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }

::selection { background: var(--ember); color: #10100f; }

:where(a, button, summary, [tabindex]):focus-visible {
  outline: 2px solid var(--ember);
  outline-offset: 3px;
  border-radius: 2px;
}

.skip-link {
  position: fixed;
  left: 12px; top: -80px;
  z-index: 10000;
  padding: 10px 16px;
  background: var(--bone);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 12px;
  transition: top .25s var(--ease);
}
.skip-link:focus { top: 12px; }

.noscript {
  padding: 18px var(--pad);
  border-top: 1px solid var(--line);
  color: var(--bone-70);
  font-family: var(--font-mono);
  font-size: 12px;
}

/* 通用小标签 */
.kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: clamp(9.5px, .72vw, 11px);
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--bone-45);
}
.kicker::before {
  content: "";
  width: 5px; height: 5px;
  background: var(--ember);
  box-shadow: 0 0 12px rgba(255, 90, 31, .9);
  flex: none;
}

/* 按钮 */
.btn {
  --btn-bg: transparent;
  --btn-fg: var(--bone);
  --btn-bd: var(--line-2);
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 24px;
  border: 1px solid var(--btn-bd);
  border-radius: 2px;
  background: var(--btn-bg);
  color: var(--btn-fg);
  font-family: var(--font-mono);
  font-size: clamp(10px, .78vw, 12px);
  letter-spacing: .16em;
  text-transform: uppercase;
  cursor: pointer;
  overflow: hidden;
  transition: color .35s var(--ease), border-color .35s var(--ease), background-color .35s var(--ease), transform .35s var(--ease);
}
.btn__arrow {
  display: inline-block;
  transition: transform .4s var(--ease);
}
.btn:hover { border-color: var(--bone); transform: translateY(-2px); }
.btn:hover .btn__arrow { transform: translateX(5px); }
.btn--primary {
  --btn-bg: var(--ember);
  --btn-fg: #14100d;
  --btn-bd: var(--ember);
  font-weight: 600;
}
.btn--primary:hover {
  --btn-bg: var(--ember-2);
  --btn-bd: var(--ember-2);
  box-shadow: 0 10px 40px -14px rgba(255, 90, 31, .8);
}
.btn--sm { padding: 10px 16px; }
.btn--block { width: 100%; justify-content: center; }

/* ---------------------------------------------------------------- 3 装饰层 */
.grain {
  position: fixed;
  inset: -60%;
  z-index: 9998;
  pointer-events: none;
  opacity: .052;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.86' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23n)'/%3E%3C/svg%3E");
  animation: grainShift 5.5s steps(6) infinite;
}
@keyframes grainShift {
  0%   { transform: translate3d(0, 0, 0); }
  16%  { transform: translate3d(-3%, 2%, 0); }
  33%  { transform: translate3d(2%, -3%, 0); }
  50%  { transform: translate3d(-2%, -2%, 0); }
  66%  { transform: translate3d(3%, 1%, 0); }
  83%  { transform: translate3d(-1%, 3%, 0); }
  100% { transform: translate3d(0, 0, 0); }
}

.cursor-glow {
  position: fixed;
  left: 0; top: 0;
  width: 560px; height: 560px;
  margin: -280px 0 0 -280px;
  z-index: 9997;
  pointer-events: none;
  border-radius: 50%;
  opacity: 0;
  background: radial-gradient(circle, rgba(255, 90, 31, .17) 0%, rgba(255, 90, 31, .06) 40%, rgba(255, 90, 31, 0) 68%);
  mix-blend-mode: screen;
  will-change: transform;
  transition: opacity .7s var(--ease);
}
@media (hover: none), (pointer: coarse) { .cursor-glow { display: none; } }

/* ---------------------------------------------------------------- 4 顶栏 */
.header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 900;
  transition: transform .5s var(--ease), background-color .5s var(--ease), border-color .5s var(--ease);
  border-bottom: 1px solid transparent;
}
.header.is-hidden { transform: translateY(-101%); }
.header.is-solid {
  background: rgba(7, 8, 10, .72);
  backdrop-filter: blur(16px) saturate(120%);
  -webkit-backdrop-filter: blur(16px) saturate(120%);
  border-bottom-color: var(--line);
}
.header__bar {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(14px, 1.6vw, 22px) var(--pad);
  display: flex;
  align-items: center;
  gap: clamp(16px, 3vw, 46px);
}
.brand {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex: none;
}
.brand__mark {
  font-family: var(--font-body);
  font-size: 20px;
  line-height: 1;
  color: var(--ember);
}
.brand__name {
  font-family: var(--font-display);
  font-size: clamp(13px, 1vw, 15px);
  font-weight: 600;
  letter-spacing: .26em;
}
.brand__tag {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .14em;
  color: var(--bone-45);
  padding-left: 10px;
  border-left: 1px solid var(--line);
}
.nav {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 32px);
  margin-left: auto;
}
.nav__link {
  position: relative;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--bone-70);
  padding: 4px 0;
  transition: color .3s var(--ease);
}
.nav__link::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 1px;
  background: var(--ember);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .45s var(--ease);
}
.nav__link:hover { color: var(--bone); }
.nav__link:hover::after, .nav__link.is-active::after { transform: scaleX(1); }
.nav__link.is-active { color: var(--bone); }

.header__right {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: none;
}
.lang {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 12px;
  border: 1px solid var(--line-2);
  border-radius: 2px;
  background: transparent;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--bone-70);
  transition: color .3s var(--ease), border-color .3s var(--ease);
}
.lang:hover { color: var(--bone); border-color: var(--bone-25); }
.lang__dot { width: 4px; height: 4px; border-radius: 50%; background: var(--ember); }

.header__progress {
  height: 1px;
  background: var(--line);
  overflow: hidden;
}
.header__progress i {
  display: block;
  height: 100%;
  width: 100%;
  background: linear-gradient(90deg, var(--ember), var(--ember-2));
  transform: scaleX(0);
  transform-origin: left center;
}

/* ---------------------------------------------------------------- 5 跳转轨道 */
.rail {
  position: fixed;
  left: clamp(10px, 1.6vw, 26px);
  top: 50%;
  z-index: 800;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 14px;
  opacity: 0;
  pointer-events: none;
  transition: opacity .6s var(--ease);
}
.rail.is-visible { opacity: 1; pointer-events: auto; }
.rail__dot {
  position: relative;
  width: 22px; height: 22px;
  display: grid;
  place-items: center;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 0;
}
.rail__dot::before {
  content: "";
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--bone-25);
  transition: background-color .35s var(--ease), transform .35s var(--ease);
}
.rail__dot::after {
  content: attr(data-label);
  position: absolute;
  left: 26px;
  top: 50%;
  transform: translateY(-50%) translateX(-6px);
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--bone-45);
  opacity: 0;
  pointer-events: none;
  transition: opacity .3s var(--ease), transform .3s var(--ease);
}
.rail__dot:hover::after { opacity: 1; transform: translateY(-50%) translateX(0); }
.rail__dot:hover::before { background: var(--bone-70); }
.rail__dot.is-active::before {
  background: var(--ember);
  transform: scale(1.5);
  box-shadow: 0 0 14px rgba(255, 90, 31, .85);
}

/* ---------------------------------------------------------------- 6 头图舞台 */
.stage {
  position: relative;
  height: calc(100vh + var(--stage-extra, 340vh));    /* 老浏览器兜底 */
  height: calc(100svh + var(--stage-extra, 340vh));   /* 地址栏收起时也稳 */
}
.stage__pin {
  position: sticky;
  top: 0;
  height: 100vh;    /* 兜底 */
  height: 100svh;
  overflow: hidden;
  isolation: isolate;
}
.stage__canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}
.stage__scrim {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(120% 90% at 50% 4%, rgba(7, 8, 10, 0) 40%, rgba(7, 8, 10, .55) 100%),
    linear-gradient(180deg, rgba(7, 8, 10, .5) 0%, rgba(7, 8, 10, 0) 26%, rgba(7, 8, 10, 0) 58%, rgba(7, 8, 10, .82) 100%);
}
/* 取景框四角刻度 */
.stage__frame {
  position: absolute;
  inset: clamp(46px, 6vh, 74px) var(--pad);
  pointer-events: none;
  opacity: .5;
}
.stage__frame i {
  position: absolute;
  width: 16px; height: 16px;
  border: 1px solid var(--line-2);
}
.stage__frame i:nth-child(1) { left: 0; top: 0; border-right: 0; border-bottom: 0; }
.stage__frame i:nth-child(2) { right: 0; top: 0; border-left: 0; border-bottom: 0; }
.stage__frame i:nth-child(3) { left: 0; bottom: 0; border-right: 0; border-top: 0; }
.stage__frame i:nth-child(4) { right: 0; bottom: 0; border-left: 0; border-top: 0; }

/* 首屏大标题区 */
.stage__intro {
  position: absolute;
  left: var(--pad);
  right: var(--pad);
  top: 50%;
  transform: translateY(-50%);
  max-width: var(--maxw);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: clamp(14px, 2vw, 26px);
  will-change: opacity, transform;
}
.stage__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(64px, 17.5vw, 280px);
  line-height: .82;
  letter-spacing: -.045em;
  margin: clamp(-6px, -.6vw, 0px) 0 0 clamp(-4px, -.4vw, 0px);
  background: linear-gradient(178deg, #ffffff 0%, var(--bone) 44%, rgba(233, 229, 221, .34) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-stretch: 87.5%;
}
.stage__sub {
  max-width: 26ch;
  font-size: clamp(15px, 1.32vw, 21px);
  line-height: 1.5;
  color: var(--bone-70);
  text-wrap: balance;
}
.stage__actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: clamp(6px, 1vw, 14px); }
.stage__hint {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--bone-25);
  margin-top: clamp(4px, 1vw, 10px);
}

/* 滚动中依次出现的 beat */
.stage__beats {
  position: absolute;
  left: var(--pad);
  bottom: clamp(74px, 15vh, 170px);
  width: min(52ch, 62vw);
  pointer-events: none;
}
.beat {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  opacity: 0;
  will-change: opacity, transform;
}
.beat__idx {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .3em;
  color: var(--ember);
  margin-bottom: clamp(8px, 1vw, 14px);
  text-shadow: 0 0 18px rgba(255, 90, 31, .55);
}
.beat__title {
  font-family: var(--font-display);
  font-size: clamp(26px, 3.6vw, 54px);
  line-height: 1.02;
  letter-spacing: -.02em;
  margin-bottom: clamp(8px, 1vw, 14px);
}
.beat__body {
  font-size: clamp(14px, 1.02vw, 17px);
  color: var(--bone-70);
  max-width: 44ch;
  line-height: 1.6;
}

/* 右侧 HUD：进度条 + 计数 */
.hud {
  position: absolute;
  right: var(--pad);
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 16px;
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--bone-45);
  pointer-events: none;
}
.hud__track {
  position: relative;
  width: 1px;
  height: clamp(90px, 20vh, 190px);
  background: var(--line);
  overflow: hidden;
}
.hud__track i {
  position: absolute;
  inset: 0 0 auto 0;
  height: 0;
  background: var(--ember);
  box-shadow: 0 0 12px rgba(255, 90, 31, .8);
}
.hud__count { font-variant-numeric: tabular-nums; color: var(--bone-70); }

/* 舞台底栏 */
.stage__foot {
  position: absolute;
  left: var(--pad);
  right: var(--pad);
  bottom: clamp(20px, 3.4vh, 40px);
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--bone-25);
  pointer-events: none;
}
.scroll-cue {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  white-space: nowrap;
}
.scroll-cue__line {
  position: relative;
  width: 1px; height: 34px;
  background: var(--line-2);
  overflow: hidden;
}
.scroll-cue__line i {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent, var(--ember));
  animation: cueRun 2.2s var(--ease) infinite;
}
@keyframes cueRun {
  0%   { transform: translateY(-100%); }
  60%  { transform: translateY(0); }
  100% { transform: translateY(100%); }
}

/* ---------------------------------------------------------------- 7 滚动大字 */
.marquee {
  position: relative;
  padding: clamp(22px, 3vw, 44px) 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  overflow: hidden;
  user-select: none;
}
.marquee + .marquee { border-top: 0; }
.marquee__track {
  display: flex;
  gap: 0;
  width: max-content;
  will-change: transform;
}
.marquee__group {
  display: flex;
  align-items: center;
  gap: clamp(20px, 3vw, 56px);
  padding-right: clamp(20px, 3vw, 56px);
  flex: none;
}
.marquee__item {
  font-family: var(--font-display);
  font-size: clamp(34px, 7vw, 108px);
  line-height: 1;
  letter-spacing: -.03em;
  white-space: nowrap;
  color: transparent;
  -webkit-text-stroke: 1px rgba(233, 229, 221, .42);
  font-stretch: 87.5%;
}
.marquee__item--fill {
  color: var(--bone);
  -webkit-text-stroke: 0;
}
.marquee__star {
  width: clamp(12px, 1.8vw, 26px);
  height: clamp(12px, 1.8vw, 26px);
  flex: none;
  color: var(--ember);
}
.marquee--reverse .marquee__item--fill { color: var(--ember); }

/* ---------------------------------------------------------------- 8 章节外壳 */
.section {
  position: relative;
  padding: clamp(64px, 9vw, 148px) var(--pad);
}
.section__inner {
  max-width: var(--maxw);
  margin: 0 auto;
}
.section--hairline { border-top: 1px solid var(--line); }
.sec-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(12px, 1.6vw, 22px);
  margin-bottom: clamp(34px, 5vw, 76px);
}
.sec-head__row {
  display: grid;
  grid-template-columns: minmax(0, .34fr) minmax(0, .66fr);
  align-items: end;
  gap: clamp(16px, 3vw, 60px);
}
.sec-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(30px, 4.9vw, 76px);
  line-height: 1.0;
  letter-spacing: -.028em;
  font-stretch: 87.5%;
  text-wrap: balance;
}
.sec-lead {
  max-width: 46ch;
  color: var(--bone-70);
}
.sec-note {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .1em;
  color: var(--bone-45);
  max-width: 42ch;
  line-height: 1.7;
}

/* ---------------------------------------------------------------- 9 图文分栏 */
.split {
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(0, .98fr);
  gap: clamp(26px, 5vw, 92px);
  align-items: start;
}
.split--reverse .split__media { order: 2; }
.split__media { position: sticky; top: 15vh; }
.split__body { display: grid; gap: clamp(18px, 2.2vw, 30px); }
.split__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(28px, 3.7vw, 60px);
  line-height: 1.02;
  letter-spacing: -.028em;
  font-stretch: 87.5%;
  text-wrap: balance;
}
.split__paras { display: grid; gap: clamp(12px, 1.4vw, 18px); color: var(--bone-70); max-width: 52ch; }
.split__list {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}
.split__list li {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: clamp(11px, 1.3vw, 16px) 0;
  border-bottom: 1px solid var(--line);
  font-size: clamp(13.5px, .95vw, 16px);
  color: var(--bone-70);
}
.split__list li::before {
  content: "";
  width: 4px; height: 4px;
  flex: none;
  background: var(--ember);
  transform: translateY(-2px) rotate(45deg);
}

/* ---------------------------------------------------------------- 媒介组件 */
.media {
  position: relative;
  overflow: hidden;
  background: var(--ink-card);
  border: 1px solid var(--line);
  isolation: isolate;
}
.media--16-9 { aspect-ratio: 16 / 9; }
.media--4-5 { aspect-ratio: 4 / 5; }
.media--1-1 { aspect-ratio: 1; }
.media > canvas,
.media > img,
.media > video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media__sheen {
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  background: linear-gradient(160deg, rgba(255, 255, 255, .07), rgba(255, 255, 255, 0) 42%);
  mix-blend-mode: overlay;
}
.media__scan {
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  opacity: .16;
  background-image: repeating-linear-gradient(0deg, rgba(0, 0, 0, .55) 0 1px, rgba(0, 0, 0, 0) 1px 3px);
}
.media__tag {
  position: absolute;
  z-index: 3;
  left: 10px;
  bottom: 10px;
  padding: 4px 7px;
  font-family: var(--font-mono);
  font-size: 8.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: rgba(233, 229, 221, .62);
  background: rgba(7, 8, 10, .58);
  border: 1px solid var(--line);
  backdrop-filter: blur(4px);
  pointer-events: none;
}
.media__btn {
  position: absolute;
  z-index: 4;
  right: 10px;
  bottom: 10px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 11px;
  border: 1px solid var(--line-2);
  background: rgba(7, 8, 10, .6);
  backdrop-filter: blur(6px);
  color: var(--bone-70);
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: .14em;
  text-transform: uppercase;
  cursor: pointer;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity .4s var(--ease), transform .4s var(--ease), color .3s, border-color .3s;
}
.media:hover .media__btn,
.media__btn:focus-visible { opacity: 1; transform: translateY(0); }
.media__btn:hover { color: var(--bone); border-color: var(--bone-25); }
.media--zoom img,
.media--zoom video { transition: transform 1.1s var(--ease); }
.media--zoom:hover img,
.media--zoom:hover video { transform: scale(1.04); }

/* ---------------------------------------------------------------- 10 场景网格 */
.gallery {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(14px, 2vw, 30px);
}
.card {
  position: relative;
  grid-column: span 4;
  border: 1px solid var(--line);
  background: var(--ink-card);
  border-radius: 2px;
  overflow: hidden;
  transform-style: preserve-3d;
  transition: transform .6s var(--ease), border-color .5s var(--ease), box-shadow .6s var(--ease);
  will-change: transform;
}
.card:hover {
  border-color: var(--line-2);
  box-shadow: 0 30px 70px -40px rgba(0, 0, 0, .9);
}
/* 卡片内的光标聚光 */
.card::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 5;
  pointer-events: none;
  opacity: 0;
  background: radial-gradient(320px circle at var(--mx, 50%) var(--my, 50%), rgba(255, 90, 31, .16), rgba(255, 90, 31, 0) 62%);
  transition: opacity .45s var(--ease);
}
.card:hover::after { opacity: 1; }
.card__body {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 14px;
  padding: clamp(12px, 1.4vw, 18px);
}
.card__title {
  font-family: var(--font-display);
  font-size: clamp(15px, 1.18vw, 19px);
  line-height: 1.2;
  letter-spacing: -.01em;
}
.card__meta {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--bone-45);
  white-space: nowrap;
}
/* 非对称排布：故意错位，避免均分的呆板 */
.gallery .card:nth-child(1) { grid-column: span 5; }
.gallery .card:nth-child(2) { grid-column: span 4; margin-top: clamp(24px, 4vw, 68px); }
.gallery .card:nth-child(3) { grid-column: span 3; margin-top: clamp(-24px, -2vw, 0px); }
.gallery .card:nth-child(4) { grid-column: span 3; margin-top: clamp(24px, 4vw, 72px); }
.gallery .card:nth-child(5) { grid-column: span 5; }
.gallery .card:nth-child(6) { grid-column: span 4; margin-top: clamp(24px, 4vw, 72px); }

/* ---------------------------------------------------------------- 11 封面 CTA */
.cover {
  position: relative;
  min-height: min(104svh, 980px);
  display: grid;
  place-items: center;
  overflow: hidden;
  isolation: isolate;
  padding: clamp(70px, 10vw, 130px) var(--pad);
  border-top: 1px solid var(--line);
}
.cover__media { position: absolute; inset: 0; z-index: 0; }
.cover__media .media { border: 0; height: 100%; aspect-ratio: auto; }
.cover__scrim {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background:
    radial-gradient(90% 70% at 50% 55%, rgba(7, 8, 10, .28), rgba(7, 8, 10, .9) 78%),
    linear-gradient(180deg, rgba(7, 8, 10, .9), rgba(7, 8, 10, .2) 32%, rgba(7, 8, 10, .92));
}
.cover__inner {
  position: relative;
  z-index: 2;
  text-align: center;
  display: grid;
  justify-items: center;
  gap: clamp(16px, 2vw, 26px);
  width: min(1100px, 92vw);
}
.cover__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(34px, 7.4vw, 116px);
  line-height: .98;
  letter-spacing: -.035em;
  font-stretch: 87.5%;
  text-wrap: balance;
}
.cover__sub { color: var(--bone-70); max-width: 34ch; }
.cover__actions { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; }

/* ---------------------------------------------------------------- 12 折叠面板 */
.acc {
  border-top: 1px solid var(--line);
  margin-top: clamp(20px, 3vw, 40px);
}
.acc__item { border-bottom: 1px solid var(--line); }
.acc__btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: clamp(16px, 2.1vw, 28px) 0;
  background: none;
  border: 0;
  text-align: left;
  cursor: pointer;
  font-family: var(--font-display);
  font-size: clamp(17px, 1.9vw, 28px);
  letter-spacing: -.012em;
  line-height: 1.24;
  color: var(--bone-70);
  transition: color .35s var(--ease);
}
.acc__btn:hover { color: var(--bone); }
.acc__item.is-open .acc__btn { color: var(--bone); }
.acc__sign {
  position: relative;
  width: 14px; height: 14px;
  flex: none;
}
.acc__sign::before,
.acc__sign::after {
  content: "";
  position: absolute;
  background: var(--bone-45);
  transition: transform .45s var(--ease), background-color .35s var(--ease);
}
.acc__sign::before { left: 0; top: 50%; width: 100%; height: 1px; transform: translateY(-50%); }
.acc__sign::after { top: 0; left: 50%; height: 100%; width: 1px; transform: translateX(-50%); }
.acc__item.is-open .acc__sign::after { transform: translateX(-50%) scaleY(0); }
.acc__item.is-open .acc__sign::before { background: var(--ember); }
.acc__panel {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows .55s var(--ease);
}
.acc__item.is-open .acc__panel { grid-template-rows: 1fr; }
.acc__panel > div { overflow: hidden; }
.acc__text {
  max-width: 68ch;
  color: var(--bone-70);
  padding-bottom: clamp(18px, 2.2vw, 30px);
  padding-right: clamp(0px, 6vw, 90px);
}

/* ---------------------------------------------------------------- 13 页脚 */
.footer {
  border-top: 1px solid var(--line);
  padding: clamp(48px, 6vw, 90px) var(--pad) clamp(24px, 3vw, 40px);
}
.footer__inner { max-width: var(--maxw); margin: 0 auto; display: grid; gap: clamp(34px, 4vw, 64px); }
.footer__top {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: clamp(22px, 3vw, 50px);
}
.footer__brand { display: grid; gap: 12px; align-content: start; }
.footer__note { color: var(--bone-45); font-size: 13px; max-width: 34ch; }
.footer__col { display: grid; gap: 10px; align-content: start; }
.footer__col-title {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--bone-25);
  margin-bottom: 4px;
}
.footer__link {
  font-size: 13.5px;
  color: var(--bone-70);
  width: fit-content;
  border-bottom: 1px solid transparent;
  transition: color .3s var(--ease), border-color .3s var(--ease);
}
.footer__link:hover { color: var(--bone); border-bottom-color: var(--ember); }
.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding-top: clamp(18px, 2vw, 26px);
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--bone-25);
}
.to-top {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: none;
  border: 0;
  cursor: pointer;
  color: var(--bone-45);
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  transition: color .3s var(--ease);
}
.to-top:hover { color: var(--bone); }
.to-top span { transition: transform .4s var(--ease); }
.to-top:hover span { transform: translateY(-3px); }

/* ---------------------------------------------------------------- 14 灯箱 */
.lightbox {
  margin: auto;
  padding: 0;
  border: 0;
  background: transparent;
  max-width: none;
  width: 100%;
  height: 100%;
  color: var(--bone);
}
.lightbox::backdrop {
  background: rgba(4, 5, 7, .9);
  backdrop-filter: blur(8px);
}
.lightbox[open] { display: grid; place-items: center; }
.lightbox__inner {
  position: relative;
  width: min(1400px, 92vw);
  display: grid;
  justify-items: center;
  gap: 0;
  animation: lbIn .5s var(--ease-out) both;
}
@keyframes lbIn {
  from { opacity: 0; transform: scale(.97) translateY(10px); }
  to   { opacity: 1; transform: none; }
}
.lightbox__frame {
  display: grid;
  place-items: center;
  max-width: 100%;
}
.lightbox__frame .media {
  border: 1px solid var(--line-2);
  width: min(92vw, calc(74vh * 16 / 9));
  max-width: 100%;
  aspect-ratio: 16 / 9;
}
.lightbox__frame .media > canvas,
.lightbox__frame .media > img,
.lightbox__frame .media > video { object-fit: contain; }
.lightbox__caption {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  max-width: 100%;
  padding: 12px 2px 0;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--bone-45);
}
.lightbox__close {
  position: fixed;
  right: clamp(14px, 2vw, 30px);
  top: clamp(14px, 2vw, 30px);
  z-index: 3;
  padding: 9px 14px;
  background: rgba(7, 8, 10, .72);
  backdrop-filter: blur(8px);
  border: 1px solid var(--line-2);
  border-radius: 2px;
  color: var(--bone-70);
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  text-transform: uppercase;
  transition: color .3s, border-color .3s;
}
.lightbox__close:hover { color: var(--bone); border-color: var(--bone-25); }

/* ---------------------------------------------------------------- 15 响应式 */
@media (max-width: 1180px) {
  .rail { display: none; }
  .gallery .card:nth-child(n) { grid-column: span 6; margin-top: 0; }
  .footer__top { grid-template-columns: minmax(0, 1fr) repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 900px) {
  .nav { display: none; }
  .split { grid-template-columns: minmax(0, 1fr); }
  .split__media { position: relative; top: 0; }
  .split--reverse .split__media { order: 0; }
  .sec-head__row { grid-template-columns: minmax(0, 1fr); align-items: start; }
  .stage__beats { width: min(46ch, 84vw); bottom: clamp(96px, 18vh, 180px); }
  .hud { display: none; }
  .footer__top { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
}

@media (max-width: 640px) {
  .stage__frame { display: none; }
  .stage__title { font-size: clamp(54px, 20vw, 110px); }
  .gallery .card:nth-child(n) { grid-column: span 12; }
  .brand__tag { display: none; }
  .footer__top { grid-template-columns: minmax(0, 1fr); }
  .media__btn { opacity: 1; transform: none; }
  .stage__foot { font-size: 8.5px; }
}

/* ---------------------------------------------------------------- 16 无障碍/降级 */
[data-reveal] {
  opacity: 0;
  transform: translate3d(0, 26px, 0);
  transition: opacity .95s var(--ease), transform .95s var(--ease);
  transition-delay: calc(var(--i, 0) * 80ms);
}
[data-reveal].is-in { opacity: 1; transform: none; }

body.is-locked { overflow: hidden; }

/* WebGL 不可用时的 CSS 兜底背景 */
.stage.no-webgl .stage__canvas { display: none; }
.stage.no-webgl .stage__pin {
  background:
    radial-gradient(120% 80% at 26% 62%, rgba(255, 90, 31, .30), rgba(255, 90, 31, 0) 55%),
    radial-gradient(90% 70% at 78% 30%, rgba(143, 166, 184, .18), rgba(143, 166, 184, 0) 60%),
    linear-gradient(180deg, #0a0b11 0%, #150f14 46%, #2a1614 72%, #07080a 100%);
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  [data-reveal] { opacity: 1; transform: none; }
  .grain { animation: none; }
}

/* ------------------------------------------ 17 手机 H5 适配（安全区 / 触屏） */
:root {
  --safe-l: env(safe-area-inset-left, 0px);
  --safe-r: env(safe-area-inset-right, 0px);
  --safe-t: env(safe-area-inset-top, 0px);
  --safe-b: env(safe-area-inset-bottom, 0px);
}

/* 刘海屏、灵动岛、横屏圆角：内容不贴边，底部不被 Home 条压住 */
.header { padding-top: var(--safe-t); }
.header__bar {
  padding-left: calc(var(--pad) + var(--safe-l));
  padding-right: calc(var(--pad) + var(--safe-r));
}
.stage__intro {
  left: calc(var(--pad) + var(--safe-l));
  right: calc(var(--pad) + var(--safe-r));
}
.stage__beats { left: calc(var(--pad) + var(--safe-l)); }
.stage__frame {
  left: calc(var(--pad) + var(--safe-l));
  right: calc(var(--pad) + var(--safe-r));
}
.stage__foot {
  left: calc(var(--pad) + var(--safe-l));
  right: calc(var(--pad) + var(--safe-r));
  bottom: calc(clamp(20px, 3.4vh, 40px) + var(--safe-b));
}
.hud { right: calc(var(--pad) + var(--safe-r)); }
.section {
  padding-left: calc(var(--pad) + var(--safe-l));
  padding-right: calc(var(--pad) + var(--safe-r));
}
.cover {
  padding-left: calc(var(--pad) + var(--safe-l));
  padding-right: calc(var(--pad) + var(--safe-r));
  padding-bottom: calc(clamp(70px, 10vw, 130px) + var(--safe-b));
}
.footer {
  padding-left: calc(var(--pad) + var(--safe-l));
  padding-right: calc(var(--pad) + var(--safe-r));
  padding-bottom: calc(clamp(24px, 3vw, 40px) + var(--safe-b));
}
.rail { left: calc(clamp(10px, 1.6vw, 26px) + var(--safe-l)); }
.skip-link { left: calc(12px + var(--safe-l)); }

/* 触屏专属：去掉只对鼠标成立的悬停位移，避免点完“卡”在悬停态 */
@media (pointer: coarse) {
  a, button { touch-action: manipulation; }
  .btn:hover { transform: none; }
  .media--zoom:hover img,
  .media--zoom:hover video { transform: none; }
  .card:hover { box-shadow: none; }
  .grain { opacity: .042; }
  .card::after { display: none; }        /* 触屏没有光标聚光 */
}