:root {
  --void: #070B18;
  --void-deep: #05070F;
  --panel: #111A33;
  --panel-deep: #0C1428;
  --violet: #7C4DFF;
  --cyan: #00E5FF;
  --magenta: #FF3DDA;
  --gold: #FFC857;
  --paper: #F5F7FF;
  --ink: #05070F;
  --haze: #B9A7FF;

  --rail-w: 272px;
  --bar-h: 62px;
  --wrap: 1200px;
  --gutter: clamp(20px, 5vw, 56px);
  --radius: 18px;
  --ease: cubic-bezier(.22, .68, .24, 1);

  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "SimSun", Georgia, "Times New Roman", serif;
  --font-sans: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Inter, system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "Roboto Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, "Courier New", monospace;

  --line: rgba(185, 167, 255, .18);
  --line-soft: rgba(185, 167, 255, .1);
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: .01em;
  color: var(--paper);
  background-color: var(--void);
  background-image:
    radial-gradient(1100px 720px at 92% -12%, rgba(124, 77, 255, .26), transparent 62%),
    radial-gradient(880px 620px at -12% 26%, rgba(0, 229, 255, .13), transparent 58%),
    radial-gradient(720px 520px at 74% 108%, rgba(255, 61, 218, .14), transparent 62%),
    linear-gradient(to right, rgba(185, 167, 255, .045) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(185, 167, 255, .045) 1px, transparent 1px);
  background-size: auto, auto, auto, 92px 92px, 92px 92px;
  background-attachment: fixed;
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 .6em;
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.24;
  letter-spacing: .015em;
  color: var(--paper);
}

h1 { font-size: clamp(2.1rem, 5.4vw, 3.7rem); }
h2 { font-size: clamp(1.6rem, 3.6vw, 2.5rem); }
h3 { font-size: clamp(1.18rem, 2.1vw, 1.5rem); }
h4 { font-size: clamp(1.02rem, 1.6vw, 1.16rem); }

p {
  margin: 0 0 1em;
  color: rgba(245, 247, 255, .78);
}

a {
  color: var(--cyan);
  text-decoration: none;
  transition: color .2s var(--ease);
}
a:hover { color: var(--paper); }

ul, ol { margin: 0 0 1em; padding-left: 1.2em; }
li { color: rgba(245, 247, 255, .78); }

img { max-width: 100%; display: block; }

button, input, select, textarea { font: inherit; color: inherit; }

code, kbd, samp, .mono { font-family: var(--font-mono); }

hr {
  border: 0;
  height: 1px;
  margin: clamp(28px, 4vw, 48px) 0;
  background: linear-gradient(90deg, transparent, var(--line), transparent);
}

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 8px;
}

::selection {
  background: rgba(124, 77, 255, .55);
  color: var(--paper);
}

/* ===== 跳转链接 ===== */
.skip-link {
  position: fixed;
  top: 12px;
  left: 50%;
  z-index: 200;
  padding: 12px 24px;
  font-size: .9rem;
  font-weight: 700;
  color: var(--ink);
  background: var(--gold);
  border-radius: 999px;
  box-shadow: 0 12px 30px -12px rgba(255, 200, 87, .9);
  transform: translate(-50%, -180%);
  transition: transform .28s var(--ease);
}
.skip-link:focus { transform: translate(-50%, 0); color: var(--ink); }

/* ===== 滚动进度 ===== */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 120;
  pointer-events: none;
  background: rgba(17, 26, 51, .55);
}
.scroll-progress > span {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--violet), var(--cyan) 55%, var(--magenta));
  box-shadow: 0 0 16px rgba(0, 229, 255, .85);
}

/* ===== 品牌标识 ===== */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--paper);
  text-decoration: none;
}
.brand:hover { color: var(--paper); }

.brand__glyph {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 40px;
  height: 40px;
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--ink);
  background: linear-gradient(135deg, var(--violet), var(--magenta));
  border-radius: 12px;
  box-shadow: 0 0 22px rgba(124, 77, 255, .55), inset 0 0 0 1px rgba(255, 255, 255, .2);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.16;
  min-width: 0;
}

.brand__name {
  font-family: var(--font-serif);
  font-size: 1.02rem;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--paper);
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: .66rem;
  letter-spacing: .16em;
  color: var(--haze);
}

/* ===== 头部骨架 ===== */
.site-header {
  position: relative;
  z-index: 90;
}

.header-bar {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 95;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  height: var(--bar-h);
  padding: 0 18px;
  background: rgba(7, 11, 24, .88);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(16px) saturate(150%);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 9px 15px;
  font-size: .78rem;
  font-weight: 600;
  letter-spacing: .08em;
  color: var(--paper);
  background: rgba(17, 26, 51, .92);
  border: 1px solid rgba(185, 167, 255, .3);
  border-radius: 999px;
  cursor: pointer;
  transition: border-color .22s var(--ease), background .22s var(--ease);
}
.nav-toggle:hover { border-color: var(--cyan); background: rgba(0, 229, 255, .12); }

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 18px;
  height: 14px;
}
.nav-toggle__bars span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--cyan);
  border-radius: 2px;
  transition: transform .3s var(--ease), opacity .2s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.nav-toggle__label {
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .16em;
  text-transform: uppercase;
}

/* ===== 折叠抽屉遮罩 ===== */
.nav-scrim {
  position: fixed;
  inset: 0;
  z-index: 96;
  background: rgba(5, 7, 15, .7);
  backdrop-filter: blur(3px);
  -webkit-backdrop-filter: blur(3px);
  opacity: 0;
  visibility: hidden;
  transition: opacity .3s var(--ease), visibility .3s linear;
}
.site-header[data-open] .nav-scrim { opacity: 1; visibility: visible; }

/* ===== 折叠抽屉 ===== */
.rail {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 98;
  display: flex;
  flex-direction: column;
  gap: 26px;
  width: min(86vw, 320px);
  padding: calc(var(--bar-h) + 26px) 22px 26px;
  overflow-y: auto;
  overscroll-behavior: contain;
  background: linear-gradient(180deg, #0B1225 0%, #070B18 100%);
  border-right: 1px solid rgba(185, 167, 255, .22);
  box-shadow: 26px 0 70px rgba(0, 0, 0, .62);
  transform: translateX(-104%);
  transition: transform .42s var(--ease);
  scrollbar-width: thin;
  scrollbar-color: rgba(124, 77, 255, .6) transparent;
}
.site-header[data-open] .rail { transform: translateX(0); }

.brand--rail { display: none; }

.rail__nav {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.rail__hint {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .26em;
  text-transform: uppercase;
  color: rgba(185, 167, 255, .72);
}

.rail__list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.rail__list::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 16px;
  bottom: 16px;
  width: 1px;
  background: linear-gradient(180deg, rgba(124, 77, 255, .8), rgba(0, 229, 255, .55) 55%, rgba(255, 61, 218, .45));
}

.rail__item { margin: 0; }

.rail__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 11px 14px 11px 30px;
  font-size: .96rem;
  font-weight: 500;
  color: rgba(245, 247, 255, .74);
  border-radius: 12px;
  transition: color .22s var(--ease), background .22s var(--ease), box-shadow .22s var(--ease);
}
.rail__link::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 50%;
  width: 9px;
  height: 9px;
  margin-top: -4.5px;
  border-radius: 50%;
  background: var(--void);
  border: 1px solid rgba(124, 77, 255, .85);
  transition: background .22s var(--ease), box-shadow .22s var(--ease), border-color .22s var(--ease);
}
.rail__link:hover {
  color: var(--paper);
  background: rgba(124, 77, 255, .13);
}
.rail__link:hover::before { border-color: var(--cyan); }

.rail__link[aria-current="page"] {
  color: var(--paper);
  background: linear-gradient(90deg, rgba(124, 77, 255, .28), rgba(0, 229, 255, .07));
  box-shadow: inset 0 0 0 1px rgba(124, 77, 255, .38);
}
.rail__link[aria-current="page"]::before {
  background: var(--violet);
  border-color: var(--violet);
  box-shadow: 0 0 0 4px rgba(124, 77, 255, .22), 0 0 18px rgba(124, 77, 255, .95);
}

.rail__idx {
  min-width: 20px;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .08em;
  color: rgba(255, 200, 87, .64);
}
.rail__link:hover .rail__idx,
.rail__link[aria-current="page"] .rail__idx { color: var(--gold); }

.rail__label { flex: 1 1 auto; }

.rail__foot {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: auto;
  padding-top: 20px;
  border-top: 1px dashed rgba(185, 167, 255, .22);
}

.rail__cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  font-size: .88rem;
  font-weight: 700;
  letter-spacing: .05em;
  color: var(--ink);
  background: linear-gradient(120deg, var(--violet), var(--magenta) 68%, var(--cyan));
  border-radius: 999px;
  box-shadow: 0 12px 30px -14px rgba(124, 77, 255, 1);
  transition: transform .22s var(--ease), box-shadow .22s var(--ease);
}
.rail__cta:hover {
  color: var(--ink);
  transform: translateY(-2px);
  box-shadow: 0 18px 38px -14px rgba(255, 61, 218, .95);
}

.rail__meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .1em;
  color: rgba(185, 167, 255, .68);
}

/* ===== 桌面端：固定星图轨道 ===== */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }

  .header-bar { display: none; }
  .nav-scrim { display: none; }
  .scroll-progress { left: var(--rail-w); }

  .rail {
    width: var(--rail-w);
    padding: 40px 26px 30px;
    box-shadow: none;
    transform: none;
    border-right: 1px solid var(--line);
  }
  .brand--rail { display: inline-flex; }
  .rail__hint { padding-left: 2px; }
}

/* ===== 页脚 ===== */
.site-footer {
  position: relative;
  z-index: 1;
  margin-top: clamp(56px, 8vw, 116px);
  padding: clamp(46px, 6vw, 84px) 0 26px;
  overflow: hidden;
  background: linear-gradient(180deg, rgba(17, 26, 51, .3) 0%, rgba(5, 7, 15, .97) 62%);
  border-top: 1px solid var(--line);
}

.footer__glow {
  position: absolute;
  top: -150px;
  left: 50%;
  width: min(780px, 130vw);
  height: 320px;
  transform: translateX(-50%);
  background: radial-gradient(closest-side, rgba(124, 77, 255, .45), transparent 72%);
  filter: blur(14px);
  pointer-events: none;
}

.footer__inner {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(30px, 4.6vw, 54px);
}

.footer__brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
}

.footer__summary {
  max-width: 44ch;
  margin: 0;
  font-size: .95rem;
  line-height: 1.8;
  color: rgba(245, 247, 255, .74);
}

.footer__col {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.footer__title {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--haze);
}

.footer__list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer__link {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: .92rem;
  color: rgba(245, 247, 255, .76);
  transition: color .2s var(--ease), transform .2s var(--ease);
}
.footer__link::before {
  content: "";
  flex: 0 0 auto;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--violet);
  box-shadow: 0 0 10px rgba(124, 77, 255, .95);
  transition: background .2s var(--ease), box-shadow .2s var(--ease);
}
.footer__link:hover { color: var(--paper); transform: translateX(3px); }
.footer__link:hover::before {
  background: var(--cyan);
  box-shadow: 0 0 12px rgba(0, 229, 255, .95);
}

.footer__list--contact { gap: 12px; }

.contact-item {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  background: rgba(17, 26, 51, .62);
  border: 1px solid var(--line);
  border-radius: 12px;
}

.contact-item__key {
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .1em;
  color: var(--haze);
}

.contact-item__val {
  font-family: var(--font-mono);
  font-size: .82rem;
  color: var(--paper);
  overflow-wrap: anywhere;
}

.copy-btn {
  padding: 6px 12px;
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--cyan);
  background: rgba(0, 229, 255, .08);
  border: 1px solid rgba(0, 229, 255, .38);
  border-radius: 999px;
  cursor: pointer;
  transition: background .2s var(--ease), color .2s var(--ease), border-color .2s var(--ease);
}
.copy-btn:hover { background: rgba(0, 229, 255, .22); color: var(--paper); }
.copy-btn[data-copied="true"] {
  color: var(--ink);
  background: var(--gold);
  border-color: var(--gold);
}

.copy-status {
  min-height: 1.3em;
  margin: 12px 0 0;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .04em;
  color: var(--gold);
}

.footer__bottom {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  margin-top: clamp(18px, 3vw, 32px);
  padding-top: 20px;
  border-top: 1px dashed rgba(185, 167, 255, .22);
}

.footer__copy,
.footer__icp {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .08em;
  color: rgba(185, 167, 255, .72);
}

.footer__icp { color: rgba(245, 247, 255, .62); }

@media (min-width: 720px) {
  .footer__inner { grid-template-columns: 1fr 1fr; }
  .footer__brand { grid-column: 1 / -1; }
}

@media (min-width: 1024px) {
  .footer__inner { grid-template-columns: 1.35fr 1fr 1.25fr; }
  .footer__brand { grid-column: auto; }
}

/* ===== 内容容器与网格 ===== */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.grid {
  display: grid;
  gap: clamp(18px, 2.4vw, 28px);
}
.grid--2,
.grid--3 { grid-template-columns: 1fr; }

@media (min-width: 680px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (min-width: 1024px) {
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

/* ===== 编号章节 ===== */
.section {
  position: relative;
  padding-block: clamp(40px, 6vw, 84px);
}

.section__head {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: clamp(20px, 3vw, 34px);
}

.section__no {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 4vw, 2.7rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: .06em;
  color: rgba(255, 200, 87, .78);
}
@supports (-webkit-text-stroke: 1px #000) {
  .section__no {
    color: transparent;
    -webkit-text-stroke: 1px rgba(255, 200, 87, .78);
  }
}

.section__title {
  margin: 0;
  font-family: var(--font-serif);
  font-size: clamp(1.55rem, 3.4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--paper);
  text-shadow: 0 0 28px rgba(124, 77, 255, .45);
}

.section__lead {
  max-width: 62ch;
  margin: 0;
  font-size: 1rem;
  color: rgba(245, 247, 255, .74);
}

/* ===== 堆叠画板 ===== */
.panel {
  position: relative;
  padding: clamp(20px, 3vw, 32px);
  background: linear-gradient(160deg, rgba(17, 26, 51, .94), rgba(9, 14, 28, .94));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 24px 60px -36px rgba(0, 0, 0, .95);
}

.panel--flat {
  background: rgba(12, 20, 40, .72);
  box-shadow: none;
}

.panel--stacked {
  box-shadow:
    6px 6px 0 -1px rgba(17, 26, 51, .92),
    6px 6px 0 0 rgba(124, 77, 255, .3),
    12px 12px 0 -1px rgba(17, 26, 51, .7),
    12px 12px 0 0 rgba(0, 229, 255, .18),
    0 30px 70px -40px rgba(0, 0, 0, .95);
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 26px;
  font-family: var(--font-sans);
  font-size: .92rem;
  font-weight: 700;
  letter-spacing: .04em;
  border: 1px solid transparent;
  border-radius: 999px;
  cursor: pointer;
  transition: transform .22s var(--ease), box-shadow .22s var(--ease), background .22s var(--ease), color .22s var(--ease), border-color .22s var(--ease);
}

.btn--primary {
  color: var(--ink);
  background: linear-gradient(120deg, var(--violet), var(--magenta) 64%, var(--cyan));
  box-shadow: 0 14px 34px -16px rgba(124, 77, 255, 1);
}
.btn--primary:hover {
  color: var(--ink);
  transform: translateY(-2px);
  box-shadow: 0 20px 44px -16px rgba(255, 61, 218, .95);
}

.btn--ghost {
  color: var(--paper);
  background: rgba(17, 26, 51, .72);
  border-color: rgba(185, 167, 255, .34);
}
.btn--ghost:hover {
  color: var(--paper);
  background: rgba(0, 229, 255, .12);
  border-color: var(--cyan);
  transform: translateY(-2px);
}

/* ===== 标签 ===== */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 12px;
  font-family: var(--font-mono);
  font-size: .68rem;
  font-weight: 600;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--cyan);
  background: rgba(0, 229, 255, .08);
  border: 1px solid rgba(0, 229, 255, .32);
  border-radius: 6px;
}

.tag--gold {
  color: var(--gold);
  background: rgba(255, 200, 87, .1);
  border-color: rgba(255, 200, 87, .36);
}

.tag--violet {
  color: var(--haze);
  background: rgba(124, 77, 255, .14);
  border-color: rgba(124, 77, 255, .44);
}

/* ===== 面包屑 ===== */
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .1em;
  color: rgba(185, 167, 255, .78);
}
.breadcrumbs li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  color: inherit;
}
.breadcrumbs li + li::before {
  content: "/";
  color: rgba(124, 77, 255, .75);
}
.breadcrumbs a { color: rgba(185, 167, 255, .88); }
.breadcrumbs a:hover { color: var(--cyan); }
.breadcrumbs [aria-current="page"] { color: var(--gold); }

/* ===== 数据 ===== */
.data-figure {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3.6vw, 2.2rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -.01em;
  color: var(--gold);
}

.data-label {
  display: block;
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: rgba(185, 167, 255, .74);
}

/* ===== 图片容器（供页面阶段放置占位图） ===== */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border: 1px solid rgba(185, 167, 255, .22);
  border-radius: var(--radius);
  background-image:
    radial-gradient(120% 90% at 18% 8%, rgba(124, 77, 255, .32), transparent 60%),
    radial-gradient(120% 90% at 92% 92%, rgba(0, 229, 255, .22), transparent 58%),
    linear-gradient(160deg, #111A33, #070B18);
}

.media-frame__img,
.media-frame > img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .5s var(--ease);
}
.media-frame:hover .media-frame__img,
.media-frame:hover > img { transform: scale(1.04); }

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame__caption {
  position: absolute;
  left: 14px;
  bottom: 14px;
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .1em;
  color: var(--paper);
  background: rgba(5, 7, 15, .74);
  border: 1px solid rgba(185, 167, 255, .28);
  border-radius: 8px;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

/* ===== 滚动显现 ===== */
html.js-on [data-reveal] {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity .72s var(--ease), transform .72s var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
}
html.js-on [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

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

  html.js-on [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .rail,
  .nav-scrim,
  .rail__link,
  .rail__cta,
  .btn,
  .footer__link,
  .copy-btn,
  .media-frame__img,
  .media-frame > img,
  .brand__glyph { transition-duration: .01ms; }

  .btn:hover,
  .rail__cta:hover,
  .footer__link:hover { transform: none; }

  .media-frame:hover .media-frame__img,
  .media-frame:hover > img { transform: none; }
}