/* ============================================================
   /assets/site.css · 华体会赛事 共享外壳
   01 基础重置 / 02 设计变量 / 03 排版底座 / 04 无障碍
   05 侧轨头部 / 06 轨道页脚 / 07 共享组件 / 08 动效降级
   ============================================================ */

/* ---------- 01 · 基础重置 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  background: #06111f;
  scroll-behavior: smooth;
}

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, ul, ol, li, dl, dd { margin: 0; }

ul, ol { padding: 0; list-style: none; }

a { color: inherit; text-decoration: none; }

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

img, svg, video { display: block; max-width: 100%; height: auto; }

::selection { background: #36f2c3; color: #04140f; }

/* ---------- 02 · 设计变量 ---------- */
:root {
  /* 竞技场色阶 */
  --abyss: #06111f;
  --deep: #0b1e33;
  --panel: #102b47;
  --struct: #1a4366;
  --silver: #9fb2c4;
  --ice: #f4f9fd;
  --neon: #36f2c3;
  --flare: #ff6b45;
  --volt: #2fa8ff;
  --slate: #617a91;

  --ink: var(--ice);
  --ink-soft: var(--silver);
  --ink-mute: var(--slate);
  --line: var(--struct);

  /* 结构与阴影 */
  --rail-w: 272px;
  --bar-h: 62px;
  --edge: 2px;
  --radius: 4px;
  --shadow-hard: 8px 8px 0 rgba(3, 9, 16, 0.9);
  --shadow-step: 6px 6px 0 var(--struct);
  --shadow-neon: 6px 6px 0 rgba(54, 242, 195, 0.22);
  --shadow-flare: 6px 6px 0 rgba(255, 107, 69, 0.24);

  /* 字号 */
  --fs-index: 12px;
  --fs-small: 14px;
  --fs-body: 17px;
  --fs-h3: clamp(1.35rem, 2.1vw, 1.9rem);
  --fs-h2: clamp(1.9rem, 3.4vw, 3.3rem);
  --fs-display: clamp(2.6rem, 5.6vw, 5.8rem);
  --fs-data: clamp(2rem, 4.6vw, 4.4rem);

  /* 字体 */
  --font-sans: "Noto Sans SC", "Source Han Sans SC", -apple-system,
    BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular,
    Menlo, Consolas, monospace;

  /* 节奏 */
  --ease: cubic-bezier(0.22, 0.7, 0.3, 1);
  --dur: 200ms;
  --gutter: clamp(18px, 5vw, 44px);
  --measure: 72ch;
  --stack-gap: 18px;
}

/* ---------- 03 · 排版底座 ---------- */
body {
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: 1.75;
  font-weight: 400;
  letter-spacing: 0.01em;
  color: var(--ice);
  background-color: var(--abyss);
  background-image:
    linear-gradient(rgba(159, 178, 196, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(159, 178, 196, 0.05) 1px, transparent 1px),
    radial-gradient(120% 80% at 100% 0%, rgba(47, 168, 255, 0.12), transparent 55%),
    radial-gradient(90% 70% at 0% 100%, rgba(54, 242, 195, 0.08), transparent 60%);
  background-size: 64px 64px, 64px 64px, 100% 100%, 100% 100%;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--ice);
  text-wrap: balance;
}

h1 { font-size: var(--fs-display); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }

p { text-wrap: pretty; }

/* ---------- 04 · 无障碍 ---------- */
:focus-visible {
  outline: 2px solid var(--volt);
  outline-offset: 3px;
  border-radius: 2px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 200;
  transform: translateY(-180%);
  padding: 10px 16px;
  background: var(--neon);
  color: #04140f;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  border: 2px solid #04140f;
  border-radius: var(--radius);
  box-shadow: 4px 4px 0 rgba(3, 9, 16, 0.9);
  transition: transform 160ms var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
  outline: 2px solid var(--ice);
  outline-offset: 3px;
}

/* ---------- 05 · 侧轨头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
}

.rail {
  position: relative;
  background: var(--deep);
  border-bottom: var(--edge) solid var(--struct);
  box-shadow: 0 6px 0 -2px rgba(3, 9, 16, 0.7);
}

.rail__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: var(--bar-h);
  padding: 0 var(--gutter);
}

.rail__brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
}

.rail__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 38px;
  background: var(--neon);
  color: #04140f;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.06em;
  border: 2px solid #04140f;
  border-radius: var(--radius);
  box-shadow: 3px 3px 0 rgba(54, 242, 195, 0.3);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.rail__brand:hover .rail__mark {
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0 rgba(54, 242, 195, 0.45);
}

.rail__name {
  font-size: 16px;
  font-weight: 900;
  letter-spacing: 0.08em;
  color: var(--ice);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  background: var(--panel);
  color: var(--ice);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  border: 2px solid var(--struct);
  border-radius: var(--radius);
  box-shadow: 3px 3px 0 rgba(3, 9, 16, 0.85);
  transition: background var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.nav-toggle:hover { background: #16395c; }

.nav-toggle:active {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 rgba(3, 9, 16, 0.85);
}

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 16px;
}

.nav-toggle__bars i {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--neon);
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.site-header[data-open="true"] .nav-toggle__bars i:first-child {
  transform: translateY(3px) rotate(45deg);
}

.site-header[data-open="true"] .nav-toggle__bars i:last-child {
  transform: translateY(-3px) rotate(-45deg);
}

/* 抽屉面板：移动端绝对定位浮出 */
.rail__body {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
  max-height: 0;
  overflow: hidden;
  padding: 0 var(--gutter);
  background: var(--deep);
  border-bottom: 0 solid var(--struct);
  box-shadow: 0 16px 0 -6px rgba(3, 9, 16, 0.65);
  transition: max-height 240ms var(--ease), padding 240ms var(--ease),
    border-bottom-width 240ms var(--ease);
}

.site-header[data-open="true"] .rail__body {
  max-height: min(78dvh, 640px);
  overflow-y: auto;
  padding: 4px var(--gutter) 22px;
  border-bottom: var(--edge) solid var(--struct);
}

.rail__version {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--silver);
}

.rail__pulse {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--neon);
  box-shadow: 0 0 0 3px rgba(54, 242, 195, 0.18);
  animation: rail-pulse 2.4s ease-in-out infinite;
}

@keyframes rail-pulse {
  0%, 100% { box-shadow: 0 0 0 3px rgba(54, 242, 195, 0.2); }
  50% { box-shadow: 0 0 0 7px rgba(54, 242, 195, 0.04); }
}

.rail__nav { width: 100%; }

.rail__list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.rail__item { display: block; }

.rail__link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 12px;
  color: var(--silver);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.02em;
  background: transparent;
  border: 2px solid transparent;
  border-left: 3px solid var(--struct);
  border-radius: var(--radius);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.rail__link:hover {
  color: var(--ice);
  background: var(--panel);
  border-color: var(--struct);
  border-left-color: var(--silver);
}

.rail__link[aria-current="page"] {
  color: var(--neon);
  background: rgba(54, 242, 195, 0.09);
  border-color: var(--struct);
  border-left-color: var(--neon);
  font-weight: 700;
}

.rail__idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--slate);
  font-variant-numeric: tabular-nums;
  transition: color var(--dur) var(--ease);
}

.rail__link:hover .rail__idx,
.rail__link[aria-current="page"] .rail__idx { color: var(--neon); }

.rail__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 4px;
}

.rail__label {
  width: 100%;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--slate);
}

.rail__action {
  display: inline-flex;
  align-items: center;
  padding: 6px 11px;
  font-size: 13px;
  color: var(--ice);
  background: rgba(16, 43, 71, 0.7);
  border: 2px solid var(--struct);
  border-radius: var(--radius);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.rail__action:hover {
  color: var(--neon);
  border-color: var(--neon);
  background: rgba(54, 242, 195, 0.1);
}

.rail__action--hot {
  color: var(--flare);
  border-color: rgba(255, 107, 69, 0.7);
  background: rgba(255, 107, 69, 0.12);
}

.rail__action--hot:hover {
  color: #200a03;
  background: var(--flare);
  border-color: var(--flare);
}

.rail__foot {
  margin-top: 2px;
  padding-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--slate);
  border-top: 2px dashed rgba(26, 67, 102, 0.9);
}

.rail__progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 120;
  pointer-events: none;
  background: rgba(26, 67, 102, 0.45);
}

.rail__progress span {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--neon), var(--volt) 55%, var(--flare));
  box-shadow: 0 0 12px rgba(54, 242, 195, 0.45);
}

/* 桌面：固定侧轨 */
@media (min-width: 1024px) {
  body { padding-inline-start: var(--rail-w); }

  .site-header {
    position: static;
    z-index: auto;
  }

  .rail {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: var(--rail-w);
    height: 100dvh;
    display: flex;
    flex-direction: column;
    gap: 18px;
    padding: 22px 18px 20px;
    overflow-y: auto;
    background: var(--deep);
    border-bottom: 0;
    border-right: var(--edge) solid var(--struct);
    border-top: 4px solid var(--neon);
    box-shadow: none;
    z-index: 80;
  }

  .rail__bar {
    min-height: 0;
    padding: 0;
    flex-wrap: wrap;
  }

  .nav-toggle { display: none; }

  .rail__body {
    position: static;
    max-height: none;
    overflow: visible;
    padding: 0;
    border-bottom: 0;
    box-shadow: none;
    background: transparent;
    display: flex;
    flex: 1 1 auto;
    flex-direction: column;
    gap: 16px;
  }

  .rail__nav { margin-top: 4px; }
  .rail__foot { margin-top: auto; }
  .rail__progress { left: var(--rail-w); }
}

/* ---------- 06 · 轨道页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 7vw, 96px);
  background: var(--deep);
  border-top: var(--edge) solid var(--struct);
  box-shadow: inset 0 4px 0 -2px rgba(54, 242, 195, 0.35);
}

.footer-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 24px;
  padding: clamp(20px, 3vw, 30px) var(--gutter);
  background:
    linear-gradient(100deg, rgba(255, 107, 69, 0.16), rgba(54, 242, 195, 0.1) 58%, transparent 92%);
  border-bottom: var(--edge) solid var(--struct);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
}

.footer-strip__label {
  flex: none;
  padding: 5px 9px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--flare);
  border: 1px solid rgba(255, 107, 69, 0.55);
  border-radius: 2px;
}

.footer-strip__text {
  flex: 1 1 240px;
  min-width: 0;
  font-size: 15px;
  color: var(--ice);
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3vw, 40px);
  padding: clamp(28px, 4vw, 52px) var(--gutter);
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-width: 0;
}

.footer-col--brand { gap: 10px; }

.footer-col__title {
  padding-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--slate);
  border-bottom: var(--edge) solid var(--struct);
}

.footer-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 66px;
  height: 44px;
  background: var(--neon);
  color: #04140f;
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.06em;
  border: 2px solid #04140f;
  border-radius: var(--radius);
  box-shadow: 5px 5px 0 rgba(54, 242, 195, 0.24);
}

.footer-brand {
  font-size: 18px;
  font-weight: 900;
  letter-spacing: 0.08em;
  color: var(--ice);
}

.footer-note {
  max-width: 34ch;
  font-size: 13px;
  line-height: 1.7;
  color: var(--silver);
}

.footer-icp {
  align-self: flex-start;
  padding: 4px 9px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--silver);
  border: 1px solid var(--struct);
  border-radius: 2px;
}

.footer-nav,
.footer-legal {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer-nav__link,
.footer-legal__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 0;
  font-size: 15px;
  color: var(--silver);
  border-bottom: 1px dashed transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.footer-nav__link::before,
.footer-legal__link::before {
  content: "—";
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--struct);
  transition: color var(--dur) var(--ease);
}

.footer-nav__link:hover,
.footer-legal__link:hover {
  color: var(--neon);
  border-bottom-color: var(--struct);
}

.footer-nav__link:hover::before,
.footer-legal__link:hover::before { color: var(--neon); }

.footer-nav__link[aria-current="page"],
.footer-legal__link[aria-current="page"] { color: var(--neon); }

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-contact__k {
  display: block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--slate);
}

.footer-contact__v {
  display: block;
  font-size: 14px;
  line-height: 1.6;
  color: var(--ice);
  overflow-wrap: anywhere;
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 18px;
  padding: 16px var(--gutter);
  font-size: 12px;
  color: var(--slate);
  background: rgba(6, 17, 31, 0.62);
  border-top: var(--edge) solid var(--struct);
}

.footer-base__mono {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--struct);
}

@media (min-width: 720px) {
  .footer-main { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 1024px) {
  .footer-main {
    grid-template-columns: 1.35fr 1fr 1.2fr 0.85fr;
    align-items: start;
  }
}

/* ---------- 07 · 共享组件 ---------- */
.shell {
  width: 100%;
  padding-inline: var(--gutter);
  padding-block: clamp(26px, 4.4vw, 52px);
}

@media (min-width: 1024px) {
  .shell {
    padding-left: clamp(32px, 4.5vw, 72px);
    padding-right: clamp(48px, 9vw, 160px);
  }
}

.section { padding-block: clamp(32px, 5vw, 72px); }

.section + .section {
  border-top: 2px solid rgba(26, 67, 102, 0.65);
}

.stack > * + * { margin-top: var(--stack-gap); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-index);
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--neon);
}

.eyebrow::before {
  content: "";
  width: 24px;
  height: 2px;
  background: currentColor;
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.data-num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--fs-data);
  font-weight: 700;
  line-height: 0.95;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--ice);
}

.data-num--neon { color: var(--neon); }
.data-num--flare { color: var(--flare); }

.panel {
  padding: clamp(18px, 2.4vw, 30px);
  background: var(--panel);
  border: var(--edge) solid var(--struct);
  border-radius: var(--radius);
  box-shadow: var(--shadow-step);
}

.panel--neon {
  border-color: rgba(54, 242, 195, 0.55);
  box-shadow: var(--shadow-neon);
}

.panel--flare {
  border-color: rgba(255, 107, 69, 0.55);
  box-shadow: var(--shadow-flare);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 0 20px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ice);
  background: var(--panel);
  border: var(--edge) solid var(--struct);
  border-radius: var(--radius);
  box-shadow: 5px 5px 0 rgba(3, 9, 16, 0.85);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    background var(--dur) var(--ease), color var(--dur) var(--ease);
}

.btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: 7px 7px 0 rgba(3, 9, 16, 0.85);
}

.btn:active {
  transform: translate(3px, 3px);
  box-shadow: 2px 2px 0 rgba(3, 9, 16, 0.85);
}

.btn--neon {
  background: var(--neon);
  color: #04140f;
  border-color: #04140f;
}

.btn--flare {
  background: var(--flare);
  color: #200a03;
  border-color: #200a03;
  box-shadow: 5px 5px 0 rgba(32, 10, 3, 0.55);
}

.btn--ghost {
  background: transparent;
  color: var(--neon);
  border-color: var(--neon);
  box-shadow: 4px 4px 0 rgba(54, 242, 195, 0.22);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 9px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--silver);
  background: rgba(26, 67, 102, 0.35);
  border: 1px solid var(--struct);
  border-radius: 2px;
}

.rule {
  height: 2px;
  border: 0;
  background: linear-gradient(90deg, var(--struct), transparent);
}

.grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(16px, 2.4vw, 28px);
}

@media (min-width: 720px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 780px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 1100px) {
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 960px) {
  .grid--sidebar {
    grid-template-columns: minmax(0, 1.7fr) minmax(0, 1fr);
  }
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--slate);
}

.breadcrumbs__link {
  color: var(--silver);
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.breadcrumbs__link:hover {
  color: var(--neon);
  border-bottom-color: var(--neon);
}

.breadcrumbs__sep { color: var(--struct); }

.breadcrumbs [aria-current="page"] { color: var(--ice); }

.prose {
  max-width: var(--measure);
  font-size: var(--fs-body);
  color: var(--silver);
}

.prose p + p { margin-top: 1em; }
.prose strong { color: var(--ice); }

.prose a {
  color: var(--volt);
  border-bottom: 2px solid rgba(47, 168, 255, 0.42);
}

.prose a:hover { border-bottom-color: var(--volt); }

.prose ul {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 1em;
}

.prose li {
  position: relative;
  padding-left: 22px;
}

.prose li::before {
  content: "—";
  position: absolute;
  left: 0;
  font-family: var(--font-mono);
  color: var(--neon);
}

.media-frame {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  background: linear-gradient(135deg, var(--panel), var(--deep));
  border: var(--edge) solid var(--struct);
  border-radius: var(--radius);
  box-shadow: var(--shadow-step);
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.82) contrast(1.05) brightness(0.92);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(
    180deg,
    rgba(11, 30, 51, 0.05),
    rgba(6, 17, 31, 0.62)
  );
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }

.media-frame__caption {
  position: absolute;
  left: 12px;
  bottom: 12px;
  z-index: 2;
  padding: 4px 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ice);
  background: rgba(6, 17, 31, 0.72);
  border: 1px solid var(--struct);
  border-radius: 2px;
}

/* 显现协议：仅在 JS 就绪时隐藏 */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 520ms var(--ease), transform 520ms var(--ease);
}

.js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 08 · 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .rail__pulse { animation: none; }

  .js [data-reveal],
  .js [data-reveal].is-in {
    opacity: 1;
    transform: none;
  }
}