/* =========================================================
   PA視訊中心 · /assets/site.css
   共享层：reset / 变量 / 中文排版 / 页头 / 页脚 / 基础组件
   ========================================================= */

/* ---------- 1. 变量 ---------- */
:root {
  --ink-0: #070B14;
  --ink-1: #0E1626;
  --ink-2: #141F33;
  --glass: rgba(20, 32, 52, 0.62);
  --cy: #3FE0D0;
  --cy-soft: #8CF5EA;
  --mg: #F0479A;
  --vi: #7A5CFF;
  --fg: #F4F7FB;
  --fg-2: #A9B4C6;
  --line: #22304A;
  --grad-signal: linear-gradient(96deg, #3FE0D0 0%, #7A5CFF 52%, #F0479A 100%);
  --grad-veil: linear-gradient(140deg, rgba(63, 224, 208, .16), rgba(122, 92, 255, .10) 50%, rgba(240, 71, 154, .14));
  --shell: 1280px;
  --gutter: clamp(18px, 4vw, 44px);
  --r-sm: 10px;
  --r-md: 16px;
  --r-lg: 26px;
  --header-h: 66px;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, "Liberation Mono", "Courier New", monospace;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  background: var(--ink-0);
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 24px);
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.8;
  letter-spacing: .01em;
  color: var(--fg);
  background: transparent;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(58vw 58vw at 84% -12%, rgba(63, 224, 208, .16), rgba(63, 224, 208, 0) 62%),
    radial-gradient(52vw 52vw at 4% 6%, rgba(122, 92, 255, .14), rgba(122, 92, 255, 0) 60%),
    radial-gradient(48vw 48vw at 62% 106%, rgba(240, 71, 154, .12), rgba(240, 71, 154, 0) 62%);
}

html.nav-open,
html.nav-open body { overflow: hidden; }

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

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }
ul, ol { margin: 0; padding: 0; }
li { list-style: none; }
button { font: inherit; color: inherit; }
a { color: var(--cy); text-decoration: none; }
a:hover { color: var(--cy-soft); }

::selection { background: rgba(63, 224, 208, .32); color: #fff; }

:focus-visible {
  outline: 2px solid var(--cy-soft);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 3. 中文排版 ---------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: -.01em;
  color: var(--fg);
  text-wrap: balance;
}
h1 { font-size: clamp(34px, 5.6vw, 60px); }
h2 { font-size: clamp(26px, 3.6vw, 38px); }
h3 { font-size: clamp(20px, 2.2vw, 24px); font-weight: 700; }
h4 { font-size: 17px; font-weight: 700; }

.meta {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .06em;
  color: var(--fg-2);
}

.eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--cy);
}

.section-title { margin: 0 0 14px; }

.prose {
  max-width: 38em;
  color: var(--fg-2);
  line-height: 1.82;
}
.prose p + p { margin-top: 1.05em; }
.prose strong { color: var(--fg); font-weight: 700; }
.prose a { border-bottom: 1px solid rgba(63, 224, 208, .42); }

/* ---------- 4. 布局容器与网格 ---------- */
.shell,
.container {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.grid { display: grid; gap: clamp(16px, 2.4vw, 28px); }
.grid--2 { grid-template-columns: 1fr; }
.grid--3 { grid-template-columns: 1fr; }

.split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
}

@media (min-width: 720px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 960px) {
  .split { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }
  .split--reverse { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }
}

/* ---------- 5. 按钮 / 标签 / 卡片 / 面包屑 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: inherit;
  font-size: 14px;
  font-weight: 700;
  line-height: 1.4;
  text-decoration: none;
  cursor: pointer;
  transition: transform .2s var(--ease), border-color .2s var(--ease), color .2s var(--ease), filter .2s var(--ease);
}
.btn--primary { background: var(--grad-signal); color: #04121A; }
.btn--primary:hover { color: #04121A; filter: brightness(1.08); transform: translateY(-1px); }
.btn--ghost { background: rgba(20, 32, 52, .55); border-color: var(--line); color: var(--fg); }
.btn--ghost:hover { border-color: var(--cy); color: var(--cy); }
.btn--quiet { padding-inline: 0; background: none; color: var(--cy); }
.btn--quiet:hover { color: var(--cy-soft); }

.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 15px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(20, 32, 52, .5);
  color: var(--fg-2);
  font-family: inherit;
  font-size: 13px;
  font-weight: 600;
  line-height: 1.5;
  cursor: pointer;
  transition: color .2s var(--ease), border-color .2s var(--ease), background-color .2s var(--ease);
}
.chip:hover { color: var(--fg); border-color: rgba(63, 224, 208, .5); }
.chip[aria-pressed="true"],
.chip.is-active { background: var(--cy); border-color: var(--cy); color: #04121A; }

.card {
  position: relative;
  padding: clamp(18px, 2.4vw, 26px);
  background: var(--glass);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  transition: border-color .22s var(--ease), transform .22s var(--ease);
}
.card:hover { border-color: rgba(63, 224, 208, .55); }
.card--solid {
  background: var(--ink-1);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 clamp(20px, 3vw, 32px);
  font-size: 13px;
  color: var(--fg-2);
}
.crumbs li { display: flex; align-items: center; gap: 8px; }
.crumbs li + li::before { content: "/"; color: var(--line); }
.crumbs a { color: var(--fg-2); }
.crumbs a:hover { color: var(--cy); }
.crumbs [aria-current="page"] { color: var(--fg); }

/* ---------- 6. 图片占位容器 ---------- */
.media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: linear-gradient(160deg, var(--ink-1), var(--ink-0) 72%);
}
.media img,
.media svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--3x4 { aspect-ratio: 3 / 4; }
.media--21x9 { aspect-ratio: 21 / 9; }

.media-glow::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(72% 62% at 18% 0%, rgba(63, 224, 208, .18), transparent 70%);
  mix-blend-mode: screen;
}
.media-caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--fg-2);
}

/* ---------- 7. 页头 · 命令栏 ---------- */
.skip-link {
  position: absolute;
  top: -120px;
  left: var(--gutter);
  z-index: 120;
  padding: 10px 18px;
  border-radius: 0 0 var(--r-sm) var(--r-sm);
  background: var(--cy);
  color: #04121A;
  font-size: 14px;
  font-weight: 700;
  transition: top .18s var(--ease);
}
.skip-link:focus { top: 0; color: #04121A; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--line);
}
.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: rgba(7, 11, 20, .88);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  backdrop-filter: blur(18px) saturate(140%);
}

.header-bar {
  display: flex;
  align-items: center;
  gap: clamp(10px, 2vw, 26px);
  min-height: var(--header-h);
  padding-block: 8px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  color: var(--fg);
}
.brand:hover { color: var(--fg); }
.brand-mark {
  position: relative;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border: 1px solid rgba(140, 245, 234, .35);
  border-radius: 9px;
  background: linear-gradient(150deg, rgba(63, 224, 208, .22), rgba(240, 71, 154, .18));
}
.brand-wave {
  display: block;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: var(--grad-signal);
  box-shadow:
    0 -5px 0 -0.5px rgba(140, 245, 234, .6),
    0 5px 0 -0.5px rgba(240, 71, 154, .6);
}
.brand-text { display: flex; flex-direction: column; }
.brand-name {
  font-size: 16px;
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: .02em;
}
.brand-sub {
  font-size: 11px;
  line-height: 1.4;
  letter-spacing: .14em;
  color: var(--fg-2);
}

/* 导航：移动端为右侧玻璃抽屉 */
.nav {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  z-index: 60;
  width: min(86vw, 340px);
  padding: calc(var(--header-h) + 22px) clamp(18px, 5vw, 26px) 36px;
  overflow-y: auto;
  border-left: 1px solid var(--line);
  background: rgba(11, 18, 32, .96);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  transform: translateX(103%);
  visibility: hidden;
  transition: transform .24s var(--ease), visibility .24s var(--ease);
}
.site-header[data-open] .nav { transform: none; visibility: visible; }

.nav-inner { display: flex; flex-direction: column; gap: 18px; }

.nav-title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--fg-2);
}

.nav-list { display: flex; flex-direction: column; gap: 2px; }

.nav-link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 14px;
  border-radius: var(--r-sm);
  font-size: 15px;
  font-weight: 600;
  color: var(--fg-2);
  transition: color .18s var(--ease), background-color .18s var(--ease);
}
.nav-link:hover { color: var(--fg); background: rgba(63, 224, 208, .08); }
.nav-idx {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: .08em;
  color: rgba(169, 180, 198, .6);
}
.nav-link[aria-current="page"] { color: var(--cy); background: rgba(63, 224, 208, .10); }
.nav-link[aria-current="page"] .nav-idx { color: var(--cy); }
.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 2px;
  top: 14px;
  bottom: 14px;
  width: 2px;
  border-radius: 2px;
  background: var(--cy);
}

.nav-quick {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}
.nav-quick a {
  display: block;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  font-size: 14px;
  font-weight: 600;
  color: var(--fg-2);
  transition: color .18s var(--ease), border-color .18s var(--ease), background-color .18s var(--ease);
}
.nav-quick a:hover { color: var(--fg); border-color: var(--cy); background: rgba(63, 224, 208, .08); }

.nav-toggle {
  position: relative;
  z-index: 70;
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-left: auto;
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(20, 32, 52, .62);
  color: var(--fg);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: border-color .18s var(--ease), color .18s var(--ease);
}
.nav-toggle:hover { border-color: var(--cy); color: var(--cy); }
.nav-toggle-bars {
  position: relative;
  display: block;
  width: 16px;
  height: 10px;
}
.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform .2s var(--ease), top .2s var(--ease);
}
.nav-toggle-bars::before { top: 0; }
.nav-toggle-bars::after { top: 8px; }
.nav-toggle-label { line-height: 1; }
.site-header[data-open] .nav-toggle-bars::before { top: 4px; transform: rotate(45deg); }
.site-header[data-open] .nav-toggle-bars::after { top: 4px; transform: rotate(-45deg); }

.nav-scrim {
  position: fixed;
  inset: 0;
  z-index: 55;
  background: rgba(3, 6, 12, .66);
  opacity: 0;
  pointer-events: none;
  transition: opacity .22s var(--ease);
}
.site-header[data-open] .nav-scrim { opacity: 1; pointer-events: auto; }

.signal-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  background: rgba(34, 48, 74, .55);
}
.signal-progress-fill {
  display: block;
  width: 0;
  height: 100%;
  background: var(--grad-signal);
  transition: width .12s linear;
}

/* 桌面端导航转为行内索引带 */
@media (min-width: 1024px) {
  .nav {
    position: static;
    width: auto;
    margin-left: auto;
    padding: 0;
    overflow: visible;
    border-left: 0;
    background: transparent;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    transform: none;
    visibility: visible;
  }
  .nav-inner {
    flex-direction: row;
    align-items: center;
    gap: clamp(8px, 1.6vw, 22px);
  }
  .nav-title { display: none; }
  .nav-list { flex-direction: row; align-items: center; gap: clamp(2px, .9vw, 12px); }
  .nav-link { padding: 8px 11px; border-radius: 8px; font-size: 14px; }
  .nav-link[aria-current="page"] { background: transparent; }
  .nav-link[aria-current="page"]::after {
    left: 11px;
    right: 11px;
    top: auto;
    bottom: 2px;
    width: auto;
    height: 2px;
  }
  .nav-quick {
    flex-direction: row;
    align-items: center;
    gap: 8px;
    padding: 0 0 0 clamp(10px, 1.4vw, 18px);
    border-top: 0;
    border-left: 1px solid var(--line);
  }
  .nav-quick a {
    padding: 7px 13px;
    border-radius: 999px;
    font-size: 12.5px;
    white-space: nowrap;
  }
  .nav-toggle { display: none; }
  .nav-scrim { display: none; }
}

@media (min-width: 1024px) and (max-width: 1339px) {
  .brand-sub { display: none; }
  .nav-idx { display: none; }
  .nav-link { padding: 8px 8px; font-size: 13.5px; }
  .nav-quick a { padding: 6px 10px; font-size: 12px; }
}

@media (max-width: 419px) {
  .brand-sub { display: none; }
}

/* ---------- 8. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(64px, 10vw, 120px);
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(14, 22, 38, .9), rgba(7, 11, 20, .98));
}
.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: min(420px, 46%);
  height: 1px;
  background: var(--grad-signal);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 5vw, 48px);
  padding-block: clamp(40px, 6vw, 64px) clamp(28px, 4vw, 42px);
}

.footer-brand-name {
  font-size: 18px;
  font-weight: 800;
  letter-spacing: .02em;
  color: var(--fg);
}
.footer-brand-line {
  margin-top: 6px;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--cy);
}
.footer-note {
  margin-top: 14px;
  max-width: 34em;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--fg-2);
}

.footer-col-title {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .18em;
  color: var(--fg-2);
}

.footer-list { display: grid; gap: 11px; }
.footer-list a {
  display: inline-block;
  font-size: 14px;
  color: var(--fg-2);
  transition: color .18s var(--ease);
}
.footer-list a::before {
  content: "";
  display: inline-block;
  width: 0;
  height: 1px;
  margin-right: 0;
  vertical-align: middle;
  background: var(--cy);
  transition: width .2s var(--ease), margin-right .2s var(--ease);
}
.footer-list a:hover,
.footer-list a:focus-visible { color: var(--cy); }
.footer-list a:hover::before,
.footer-list a:focus-visible::before { width: 10px; margin-right: 8px; }

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px 24px;
  padding-block: 20px 30px;
  border-top: 1px solid var(--line);
}
.legal-line {
  max-width: 62em;
  font-size: 12.5px;
  line-height: 1.75;
  color: var(--fg-2);
}
.legal-meta {
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: .04em;
  color: var(--fg-2);
}

@media (min-width: 720px) {
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (min-width: 1024px) {
  .footer-grid { grid-template-columns: 1.5fr 1fr 1fr 1fr; }
}

/* ---------- 9. 显现动画 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .5s var(--ease), transform .5s var(--ease);
}
[data-reveal].is-visible { opacity: 1; transform: none; }

/* ---------- 10. 减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  [data-reveal] { opacity: 1; transform: none; }
}

/* ---------- 11. 打印 ---------- */
@media print {
  body { background: #fff; color: #111; }
  body::before { display: none; }
  .site-header, .site-footer { position: static; background: none; }
  .nav-toggle, .nav-scrim, .signal-progress, .skip-link { display: none; }
}