/* ==========================================================================
   KAIYUN 全站 — /assets/site.css
   共享外壳：转播控制室轨道头部 + 信号页脚 + 通用组件基座
   ========================================================================== */

/* ---------- 1. Reset ---------- */
*,
*::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: 100dvh;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.008em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, p, figure, blockquote { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video, canvas { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
address { font-style: normal; }
main { display: block; }
strong { font-weight: 700; }

/* ---------- 2. Tokens ---------- */
:root {
  --ink: #0A1230;
  --ink-2: #121C45;
  --ink-3: #080E26;
  --ink-4: #0B1434;
  --cyan: #35F2DC;
  --cyan-dim: rgba(53, 242, 220, 0.12);
  --orange: #FF6B2C;
  --violet: #8B7BFF;
  --green: #42D392;
  --silver: #AEB9CF;
  --paper: #F5F0E6;
  --black: #0B0D14;

  --line: rgba(174, 185, 207, 0.16);
  --line-strong: rgba(174, 185, 207, 0.32);
  --line-cyan: rgba(53, 242, 220, 0.28);

  --font-display: "Barlow Condensed", "Oswald", "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-editorial: "Noto Serif SC", "Source Han Serif SC", "Songti SC", Georgia, serif;

  --rail-w: 92px;
  --radius: 3px;
  --shadow-paper: 0 18px 44px rgba(3, 6, 18, 0.45);
  --shadow-cyan: 0 0 0 1px rgba(53, 242, 220, 0.32), 0 10px 28px rgba(53, 242, 220, 0.16);
  --ease: cubic-bezier(0.22, 0.7, 0.2, 1);
}

/* ---------- 3. 中文排版与焦点 ---------- */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: 0.01em;
  text-wrap: balance;
}

p { line-height: 1.8; text-wrap: pretty; }
p + p { margin-top: 0.85em; }

.mono,
[data-mono] {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.03em;
}

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

::selection {
  background: var(--cyan);
  color: #04120F;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ---------- 4. 布局基座 ---------- */
@media (min-width: 1080px) {
  body { padding-left: var(--rail-w); }
  html { scroll-padding-top: 28px; }
}

.container {
  width: min(1280px, calc(100% - 2.5rem));
  margin-inline: auto;
}

@media (max-width: 640px) {
  .container { width: min(1280px, calc(100% - 1.5rem)); }
}

.section { margin-block: clamp(40px, 6vw, 84px); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 14px 24px;
  padding-bottom: 16px;
  margin-bottom: clamp(20px, 3vw, 34px);
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
}

.eyebrow::before {
  content: "";
  width: 16px;
  height: 2px;
  background: var(--cyan);
}

.grid { display: grid; gap: var(--gap, 22px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--auto { grid-template-columns: repeat(auto-fit, minmax(min(100%, 258px), 1fr)); }

@media (max-width: 900px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 620px) {
  .grid--2,
  .grid--3 { grid-template-columns: minmax(0, 1fr); }
}

/* ---------- 5. 跳过链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 220;
  display: inline-block;
  padding: 10px 18px;
  background: var(--cyan);
  color: #04120F;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.04em;
  border-radius: 2px;
  transform: translateY(-180%);
  transition: transform 0.2s var(--ease);
}

.skip-link:focus,
.skip-link:focus-visible {
  transform: translateY(0);
  outline-offset: 2px;
}

/* ---------- 6. 头部外壳 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 70;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  background: rgba(10, 18, 48, 0.96);
  border-bottom: 1px solid var(--line-cyan);
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  color: var(--paper);
}

.brand__mark {
  display: grid;
  place-items: center;
  flex: 0 0 36px;
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--cyan) 0%, #1BB6A8 100%);
  color: #04120F;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 16px;
  line-height: 1;
  letter-spacing: 0.02em;
  border-radius: 2px;
  box-shadow: var(--shadow-cyan);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}

.brand__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 15px;
  line-height: 1.1;
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.brand__line {
  font-family: var(--font-mono);
  font-size: 9px;
  line-height: 1.2;
  letter-spacing: 0.14em;
  color: var(--silver);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 抽屉按钮 */
.nav-toggle {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 13px;
  color: var(--cyan);
  background: rgba(53, 242, 220, 0.07);
  border: 1px solid var(--line-cyan);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease);
}

.nav-toggle:hover { background: rgba(53, 242, 220, 0.14); }

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 16px;
  height: 2px;
  background: currentColor;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background: currentColor;
  transition: transform 0.26s var(--ease), opacity 0.2s var(--ease);
}

.nav-toggle__bars::before { top: -5px; }
.nav-toggle__bars::after { top: 5px; }

.site-header[data-open] .nav-toggle__bars { background: transparent; }
.site-header[data-open] .nav-toggle__bars::before { transform: translateY(5px) rotate(45deg); }
.site-header[data-open] .nav-toggle__bars::after { transform: translateY(-5px) rotate(-45deg); }

.nav-toggle__label { display: inline; }

/* 导航容器：移动端 = 右侧抽屉 */
.site-nav {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  z-index: 95;
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: min(86vw, 344px);
  padding: 20px 20px 26px;
  overflow-y: auto;
  background: var(--ink-4);
  border-left: 1px solid var(--line-cyan);
  box-shadow: -28px 0 68px rgba(0, 0, 0, 0.62);
  transform: translateX(104%);
  visibility: hidden;
  transition: transform 0.34s var(--ease), visibility 0.34s var(--ease);
}

.site-header[data-open] .site-nav {
  transform: translateX(0);
  visibility: visible;
}

.site-nav__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 16px;
  margin-bottom: 6px;
  border-bottom: 1px solid var(--line);
}

.site-nav__eyebrow {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--silver);
}

.site-nav__close {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  color: var(--cyan);
  border: 1px solid var(--line-cyan);
  border-radius: 2px;
  font-size: 13px;
  line-height: 1;
  transition: background 0.2s var(--ease);
}

.site-nav__close:hover { background: rgba(53, 242, 220, 0.12); }

.site-nav__list {
  display: flex;
  flex-direction: column;
}

.site-nav__item {
  border-bottom: 1px solid rgba(174, 185, 207, 0.12);
}

.site-nav__item:first-child {
  border-top: 1px solid rgba(174, 185, 207, 0.12);
}

.site-nav__link {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 13px 4px 13px 14px;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.05em;
  color: rgba(245, 240, 230, 0.84);
  transition: color 0.2s var(--ease), background 0.2s var(--ease);
}

.site-nav__link::after {
  content: "";
  width: 5px;
  height: 5px;
  flex: 0 0 auto;
  background: rgba(174, 185, 207, 0.45);
  transform: rotate(45deg);
  transition: background 0.2s var(--ease);
}

.site-nav__link:hover {
  color: var(--paper);
  background: rgba(245, 240, 230, 0.05);
}

.site-nav__link:hover::after { background: var(--cyan); }

.site-nav__link[aria-current="page"] {
  color: var(--cyan);
  background: rgba(53, 242, 220, 0.09);
}

.site-nav__link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 3px;
  height: 20px;
  transform: translateY(-50%);
  background: var(--cyan);
}

.site-nav__link[aria-current="page"]::after { background: var(--cyan); }

.site-nav__foot {
  margin-top: auto;
  padding-top: 18px;
  display: grid;
  gap: 10px;
}

.site-nav__hint {
  font-family: var(--font-mono);
  font-size: 10.5px;
  line-height: 1.6;
  letter-spacing: 0.06em;
  color: rgba(174, 185, 207, 0.78);
}

/* 遮罩 */
.nav-scrim {
  position: fixed;
  inset: 0;
  z-index: 90;
  background: rgba(6, 9, 22, 0.7);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s var(--ease);
}

.site-header[data-open] .nav-scrim {
  opacity: 1;
  pointer-events: auto;
}

body.is-nav-open { overflow: hidden; }

/* 信号进度条 */
.rail-progress {
  position: fixed;
  top: 0;
  right: 0;
  width: 3px;
  height: 0;
  z-index: 96;
  pointer-events: none;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--violet) 58%, var(--orange) 100%);
  transition: height 0.12s linear;
}

/* ---------- 7. 头部桌面：96px 侧边轨道 ---------- */
@media (min-width: 1080px) {
  .site-header {
    position: fixed;
    inset: 0 auto 0 0;
    width: var(--rail-w);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 20px 0 18px;
    background: linear-gradient(180deg, var(--ink-4) 0%, var(--ink) 52%, var(--ink-3) 100%);
    border-bottom: 0;
    border-right: 1px solid var(--line);
  }

  .brand {
    flex-direction: column;
    align-items: center;
    gap: 10px;
    padding: 0 8px;
    margin-bottom: 18px;
  }

  .brand__mark {
    flex: 0 0 40px;
    width: 40px;
    height: 40px;
    font-size: 17px;
  }

  .brand__text { align-items: center; gap: 3px; text-align: center; }

  .brand__name {
    font-size: 11.5px;
    letter-spacing: 0.02em;
    white-space: normal;
  }

  .brand__line {
    font-size: 8.5px;
    letter-spacing: 0.06em;
    white-space: normal;
    overflow: visible;
    max-width: 74px;
  }

  .nav-toggle { display: none; }
  .nav-scrim { display: none; }

  .site-nav {
    position: static;
    transform: none;
    visibility: visible;
    width: auto;
    height: auto;
    min-height: 0;
    flex: 1 1 auto;
    padding: 0 6px;
    gap: 0;
    background: none;
    border: 0;
    box-shadow: none;
    overflow-y: auto;
    scrollbar-width: thin;
  }

  .site-nav__top { display: none; }

  .site-nav__list {
    flex: 0 0 auto;
    padding-top: 4px;
    gap: 2px;
  }

  .site-nav__item { border: 0; }
  .site-nav__item:first-child { border: 0; }

  .site-nav__link {
    justify-content: center;
    padding: 11px 2px;
    font-size: 12px;
    letter-spacing: 0.06em;
    text-align: center;
    border-radius: 2px;
    color: rgba(245, 240, 230, 0.78);
  }

  .site-nav__link::after { display: none; }

  .site-nav__link:hover {
    color: var(--paper);
    background: rgba(245, 240, 230, 0.07);
  }

  .site-nav__link[aria-current="page"] {
    color: var(--cyan);
    background: rgba(53, 242, 220, 0.13);
  }

  .site-nav__link[aria-current="page"]::before {
    left: auto;
    right: -6px;
    top: 50%;
    width: 3px;
    height: 18px;
    transform: translateY(-50%);
    background: var(--cyan);
  }

  .site-nav__foot {
    margin-top: auto;
    padding-top: 14px;
    gap: 6px;
  }

  .site-nav__hint { display: none; }
}

/* ---------- 8. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 8vw, 96px);
  background: linear-gradient(180deg, var(--ink-3) 0%, var(--ink) 46%, #06091A 100%);
  border-top: 1px solid var(--line-cyan);
  color: rgba(245, 240, 230, 0.86);
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: repeating-linear-gradient(
    90deg,
    var(--cyan) 0 18px,
    transparent 18px 34px,
    var(--orange) 34px 46px,
    transparent 46px 66px
  );
  opacity: 0.55;
}

.footer__inner {
  width: min(1280px, calc(100% - 2.5rem));
  margin-inline: auto;
  padding: clamp(36px, 6vw, 74px) 0 26px;
}

.footer__head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 52px);
}

@media (min-width: 820px) {
  .footer__head {
    grid-template-columns: 1.15fr 0.85fr 0.95fr;
    align-items: start;
  }
}

.footer__logo {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 3vw, 28px);
  letter-spacing: 0.03em;
  color: var(--paper);
  line-height: 1.1;
}

.footer__logo-sub {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.footer__tagline {
  margin-top: 14px;
  max-width: 34em;
  font-size: 14px;
  line-height: 1.85;
  color: rgba(245, 240, 230, 0.72);
}

.footer__badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  border: 1px solid currentColor;
  border-radius: 2px;
  background: transparent;
}

.chip--cyan { color: var(--cyan); background: rgba(53, 242, 220, 0.08); }
.chip--orange { color: var(--orange); background: rgba(255, 107, 44, 0.08); }
.chip--violet { color: var(--violet); background: rgba(139, 123, 255, 0.1); }
.chip--green { color: var(--green); background: rgba(66, 211, 146, 0.1); }
.chip--silver { color: var(--silver); background: rgba(174, 185, 207, 0.08); }

.footer__nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.footer__title {
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
}

.footer__links a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 0;
  font-size: 14px;
  color: rgba(245, 240, 230, 0.78);
  transition: color 0.2s var(--ease), gap 0.2s var(--ease);
}

.footer__links a::before {
  content: "";
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: rgba(53, 242, 220, 0.5);
  transition: background 0.2s var(--ease);
}

.footer__links a:hover { color: var(--cyan); gap: 11px; }
.footer__links a:hover::before { background: var(--cyan); }

.footer__contact { display: grid; gap: 8px; }

.footer__contact li {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 10px;
  align-items: baseline;
  font-size: 12.5px;
  line-height: 1.6;
}

.footer__k {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: rgba(174, 185, 207, 0.72);
}

.footer__v {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: rgba(245, 240, 230, 0.88);
  word-break: break-word;
}

.footer__note {
  margin-top: 14px;
  font-size: 11.5px;
  line-height: 1.75;
  color: rgba(174, 185, 207, 0.72);
  padding-left: 10px;
  border-left: 2px solid var(--line-cyan);
}

.footer__legal {
  margin-top: clamp(28px, 4vw, 48px);
  padding-top: 18px;
  border-top: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: rgba(174, 185, 207, 0.82);
}

.footer__copy { margin: 0; }

.footer__legal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.footer__legal-links a {
  color: rgba(174, 185, 207, 0.86);
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.footer__legal-links a:hover {
  color: var(--cyan);
  border-color: var(--cyan);
}

.footer__icp { margin: 0; color: rgba(174, 185, 207, 0.6); }

/* ---------- 9. 通用组件 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.2;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.2s var(--ease), color 0.2s var(--ease),
              border-color 0.2s var(--ease), transform 0.2s var(--ease);
}

.btn--primary {
  background: var(--cyan);
  color: #04120F;
  box-shadow: 0 8px 24px rgba(53, 242, 220, 0.2);
}

.btn--primary:hover { background: #62F8E8; transform: translateY(-1px); }

.btn--signal {
  background: var(--orange);
  color: #170803;
  box-shadow: 0 8px 24px rgba(255, 107, 44, 0.22);
}

.btn--signal:hover { background: #FF824F; transform: translateY(-1px); }

.btn--ghost {
  background: transparent;
  color: var(--paper);
  border-color: var(--line-strong);
}

.btn--ghost:hover {
  color: var(--cyan);
  border-color: var(--cyan);
  background: rgba(53, 242, 220, 0.08);
}

.btn--sm { padding: 8px 14px; font-size: 12.5px; }
.btn--full { width: 100%; }

.breadcrumb {
  margin-bottom: clamp(16px, 2.4vw, 26px);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: rgba(174, 185, 207, 0.78);
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.breadcrumb__item { display: inline-flex; align-items: center; gap: 8px; }

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: rgba(174, 185, 207, 0.42);
}

.breadcrumb a { color: rgba(245, 240, 230, 0.8); }
.breadcrumb a:hover { color: var(--cyan); }
.breadcrumb__item[aria-current="page"] { color: var(--cyan); }

.paper-card {
  position: relative;
  background: var(--paper);
  color: var(--black);
  border-radius: var(--radius);
  padding: clamp(20px, 3vw, 32px);
  box-shadow: var(--shadow-paper);
}

.paper-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--violet) 55%, var(--orange) 100%);
  border-radius: var(--radius) var(--radius) 0 0;
}

.paper-card h2,
.paper-card h3 { color: var(--black); }
.paper-card p { color: rgba(11, 13, 20, 0.82); }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--silver);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: rgba(174, 185, 207, 0.06);
}

.tag--cyan { color: var(--cyan); border-color: var(--line-cyan); background: var(--cyan-dim); }
.tag--orange { color: var(--orange); border-color: rgba(255, 107, 44, 0.35); background: rgba(255, 107, 44, 0.1); }
.tag--violet { color: var(--violet); border-color: rgba(139, 123, 255, 0.38); background: rgba(139, 123, 255, 0.12); }
.tag--green { color: var(--green); border-color: rgba(66, 211, 146, 0.36); background: rgba(66, 211, 146, 0.12); }

/* ---------- 10. 可复用图片容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  width: 100%;
  background-color: var(--ink-2);
  background-image:
    repeating-linear-gradient(0deg, rgba(53, 242, 220, 0.09) 0 1px, transparent 1px 6px),
    repeating-linear-gradient(90deg, rgba(174, 185, 207, 0.07) 0 1px, transparent 1px 6px),
    linear-gradient(135deg, rgba(18, 28, 69, 0.96) 0%, rgba(10, 18, 48, 0.96) 100%);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  isolation: isolate;
}

.media-frame img,
.media-frame video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(
    0deg,
    rgba(6, 9, 22, 0.22) 0 1px,
    transparent 1px 4px
  );
  opacity: 0.5;
}

.media-frame--wide { aspect-ratio: 16 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--portrait { aspect-ratio: 4 / 5; }
.media-frame--hero { aspect-ratio: 21 / 9; }

.media-frame__label {
  position: absolute;
  left: 10px;
  bottom: 10px;
  z-index: 2;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--paper);
  background: rgba(10, 18, 48, 0.82);
  border: 1px solid var(--line-cyan);
  border-radius: 2px;
}

.media-frame--cyan .media-frame__label { color: #06120F; background: var(--cyan); border-color: var(--cyan); }
.media-frame--orange .media-frame__label { color: #170803; background: var(--orange); border-color: var(--orange); }
.media-frame--violet .media-frame__label { color: #0A0620; background: var(--violet); border-color: var(--violet); }

/* ---------- 11. 滚动显现 ---------- */
[data-reveal] {
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
  transition-delay: calc(var(--reveal-i, 0) * 55ms);
}

html.js-ready [data-reveal] {
  opacity: 0;
  transform: translate3d(0, 18px, 0);
}

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

/* ---------- 12. 降级与 reduced-motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

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

  .skip-link,
  .site-nav,
  .nav-scrim,
  .rail-progress,
  .nav-toggle__bars::before,
  .nav-toggle__bars::after,
  .btn,
  .site-nav__link,
  .footer__links a {
    transition: none !important;
  }

  .btn:hover { transform: none; }
}

@media (max-width: 420px) {
  .brand__line { display: none; }
  .footer__nav { grid-template-columns: minmax(0, 1fr); }
}