```css
/* ============================================================
   风驰影院 - 极速播放体验
   风格：深空蓝调 + 霓虹青蓝渐变 · 毛玻璃卡片
   ============================================================ */

/* ---------- CSS 变量 ---------- */
:root {
  --brand-dark: #0d1b2a;
  --brand-mid: #16324f;
  --brand-blue: #1a5fb4;
  --brand-deep: #0d3d78;
  --accent: #4fc3f7;
  --accent-glow: rgba(79, 195, 247, 0.45);
  --accent-soft: rgba(79, 195, 247, 0.12);

  --bg: #f5f7fa;
  --bg-alt: #eef4fb;
  --surface: #ffffff;
  --surface-glass: rgba(255, 255, 255, 0.72);
  --surface-glass-strong: rgba(255, 255, 255, 0.88);
  --border: #e1e8f0;
  --border-glass: rgba(255, 255, 255, 0.55);

  --text: #1c2533;
  --text-soft: #33415c;
  --text-mute: #5b6b7f;
  --text-faint: #7a8a9e;

  --link: #1a5fb4;
  --link-hover: #0d3d78;

  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 18px;
  --radius-pill: 999px;

  --shadow-sm: 0 2px 8px rgba(13, 27, 42, 0.08);
  --shadow: 0 6px 24px rgba(13, 27, 42, 0.10);
  --shadow-lg: 0 16px 48px rgba(13, 27, 42, 0.16);
  --shadow-glow: 0 8px 32px rgba(79, 195, 247, 0.28);

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --dur: 0.35s;

  --maxw: 1200px;
  --header-h: 64px;
}

/* ---------- 基础重置 ---------- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: calc(var(--header-h) + 16px);
}

body {
  font-family: "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  background-image:
    radial-gradient(circle at 12% -8%, rgba(79, 195, 247, 0.14), transparent 42%),
    radial-gradient(circle at 92% 4%, rgba(26, 95, 180, 0.10), transparent 46%);
  background-attachment: fixed;
  line-height: 1.8;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

a {
  color: var(--link);
  text-decoration: none;
  transition: color var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

a:hover {
  color: var(--link-hover);
}

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

ul,
ol {
  list-style-position: outside;
}

::selection {
  background: var(--accent);
  color: var(--brand-dark);
}

/* ---------- 无障碍跳转 ---------- */
.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 999;
}

.skip:focus {
  left: 12px;
  top: 12px;
  background: var(--brand-dark);
  color: #fff;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-glow);
  outline: 2px solid var(--accent);
}

/* ============================================================
   头部导航
   ============================================================ */
header.site {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 27, 42, 0.86);
  -webkit-backdrop-filter: blur(18px) saturate(160%);
  backdrop-filter: blur(18px) saturate(160%);
  color: #fff;
  border-bottom: 1px solid rgba(79, 195, 247, 0.18);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.28);
  transition: background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.nav-wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 0 20px;
  height: var(--header-h);
}

/* 品牌标识 */
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-weight: 700;
  font-size: 20px;
  letter-spacing: 0.5px;
  white-space: nowrap;
  transition: transform var(--dur) var(--ease);
}

.brand:hover {
  color: #fff;
  transform: translateY(-1px);
}

.brand svg {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  box-shadow: 0 0 0 1px rgba(79, 195, 247, 0.4), 0 4px 14px var(--accent-glow);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.brand:hover svg {
  transform: rotate(-6deg) scale(1.06);
  box-shadow: 0 0 0 1px rgba(79, 195, 247, 0.7), 0 6px 22px var(--accent-glow);
}

/* 主导航 */
nav.main ul {
  display: flex;
  align-items: center;
  gap: 6px;
  list-style: none;
}

nav.main a {
  position: relative;
  display: inline-block;
  color: #dbe4f0;
  font-size: 15px;
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}

nav.main a::after {
  content: "";
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 2px;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), transparent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur) var(--ease);
}

nav.main a:hover {
  color: var(--accent);
  background: rgba(79, 195, 247, 0.10);
}

nav.main a:hover::after {
  transform: scaleX(1);
}

/* 搜索与工具按钮 */
.search-box {
  display: flex;
  align-items: center;
  gap: 8px;
}

.search-box input[type="search"] {
  border: 1px solid rgba(79, 195, 247, 0.35);
  background: rgba(255, 255, 255, 0.08);
  color: #eaf3fb;
  border-radius: var(--radius-pill);
  padding: 7px 14px;
  font-size: 14px;
  width: 160px;
  outline: none;
  transition: width var(--dur) var(--ease), border-color var(--dur) var(--ease),
    background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.search-box input[type="search"]::placeholder {
  color: #8fa2ba;
}

.search-box input[type="search"]:focus {
  width: 200px;
  border-color: var(--accent);
  background: rgba(255, 255, 255, 0.14);
  box-shadow: 0 0 0 3px rgba(79, 195, 247, 0.22);
}

.search-box button {
  border: none;
  border-radius: var(--radius-pill);
  padding: 7px 16px;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  background: linear-gradient(135deg, var(--accent), #2b9fd8);
  color: var(--brand-dark);
  box-shadow: 0 4px 14px var(--accent-glow);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    filter var(--dur) var(--ease);
}

.search-box button:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px var(--accent-glow);
  filter: brightness(1.06);
}

.search-box button:active {
  transform: translateY(0);
}

.theme-btn {
  background: rgba(79, 195, 247, 0.08);
  border: 1px solid rgba(79, 195, 247, 0.55);
  color: var(--accent);
  border-radius: var(--radius-pill);
  padding: 7px 14px;
  cursor: pointer;
  font-size: 14px;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.theme-btn:hover {
  background: rgba(79, 195, 247, 0.18);
  box-shadow: 0 0 0 3px rgba(79, 195, 247, 0.16);
  transform: translateY(-1px);
}

.menu-btn {
  display: none;
  background: rgba(79, 195, 247, 0.08);
  border: 1px solid rgba(79, 195, 247, 0.55);
  color: var(--accent);
  padding: 7px 14px;
  border-radius: var(--radius-pill);
  font-size: 14px;
  cursor: pointer;
  transition: background var(--dur) var(--ease);
}

.menu-btn:hover {
  background: rgba(79, 195, 247, 0.18);
}

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 16px 20px 0;
  font-size: 14px;
  color: var(--text-mute);
}

.breadcrumb a {
  color: var(--link);
  border-bottom: 1px dashed transparent;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.breadcrumb a:hover {
  color: var(--link-hover);
  border-bottom-color: var(--link-hover);
}

.breadcrumb span {
  color: var(--text-faint);
}

/* ============================================================
   Banner 轮播
   ============================================================ */
.banner {
  position: relative;
  max-width: var(--maxw);
  margin: 16px auto 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--brand-dark);
  box-shadow: var(--shadow-lg), 0 0 0 1px rgba(79, 195, 247, 0.16);
}

.banner::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(circle at 80% 20%, rgba(79, 195, 247, 0.22), transparent 46%),
    radial-gradient(circle at 12% 88%, rgba(26, 95, 180, 0.26), transparent 52%);
  mix-blend-mode: screen;
}

.slides {
  position: relative;
  height: 360px;
}

.slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transform: scale(1.04);
  transition: opacity 0.9s var(--ease), transform 1.2s var(--ease);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  color: #fff;
  text-align: center;
  padding: 24px;
  pointer-events: none;
}

.slide.active {
  opacity: 1;
  transform: scale(1);
  pointer-events: auto;
}

.slide h2 {
  position: relative;
  font-size: 32px;
  line-height: 1.35;
  margin-bottom: 14px;
  letter-spacing: 1px;
  text-shadow: 0 4px 28px rgba(0, 0, 0, 0.45);
  animation: fadeUp 0.9s var(--ease) both;
}

.slide p {
  position: relative;
  font-size: 16px;
  color: #d3e2f2;
  max-width: 660px;
  text-shadow: 0 2px 16px rgba(0, 0, 0, 0.4);
  animation: fadeUp 0.9s 0.12s var(--ease) both;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 轮播指示点 */
.dots {
  position: absolute;
  bottom: 18px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 3;
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  background: rgba(13, 27, 42, 0.35);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.14);
}

.dots span {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.42);
  cursor: pointer;
  transition: all var(--dur) var(--ease);
}

.dots span:hover {
  background: rgba(255, 255, 255, 0.75);
  transform: scale(1.2);
}

.dots span.active {
  width: 26px;
  border-radius: var(--radius-pill);
  background: var(--accent);
  box-shadow: 0 0 12px var(--accent-glow);
}

/* ============================================================
   主内容区
   ============================================================ */
main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px 72px;
}

section {
  position: relative;
  margin-top: 40px;
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  backdrop-filter: blur(14px) saturate(140%);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 34px 32px;
  box-shadow: var(--shadow);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease), transform var(--dur) var(--ease);
}

section:hover {
  box-shadow: var(--shadow-lg);
}

section h2 {
  position: relative;
  font-size: 24px;
  line-height: 1.4;
  color: var(--brand-dark);
  padding-left: 18px;
  margin-bottom: 22px;
  letter-spacing: 0.5px;
}

section h2::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 5px;
  height: 26px;
  border-radius: var(--radius-pill);
  background: linear-gradient(180deg, var(--accent), var(--brand-blue));
  box-shadow: 0 0 14px var(--accent-glow);
}

section h3 {
  font-size: 19px;
  color: var(--brand-mid);
  margin: 26px 0 10px;
  padding-left: 2px;
  letter-spacing: 0.3px;
}

section h4 {
  font-size: 16px;
  color: var(--brand-blue);
  margin: 18px 0 8px;
}

section p {
  margin-bottom: 12px;
  color: var(--text-soft);
  text-align: justify;
  text-justify: inter-ideograph;
}

/* ============================================================
   数据统计卡片
   ============================================================ */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  margin-top: 26px;
}

.stat {
  position: relative;
  overflow: hidden;
  background: linear-gradient(150deg, rgba(79, 195, 247, 0.14), rgba(26, 95, 180, 0.06));
  border: 1px solid rgba(79, 195, 247, 0.24);
  border-radius: var(--radius);
  padding: 22px 18px;
  text-align: center;
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.stat::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, rgba(79, 195, 247, 0.28), transparent 68%);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
  pointer-events: none;
}

.stat:hover {
  transform: translateY(-5px);
  border-color: rgba(79, 195, 247, 0.55);
  box-shadow: var(--shadow-glow);
}

.stat:hover::before {
  opacity: 1;
}

.stat .num {
  position: relative;
  font-size: 34px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--brand-blue);
  letter-spacing: 0.5px;
  font-variant-numeric: tabular-nums;
}

.stat .label {
  position: relative;
  font-size: 14px;
  color: var(--text-mute);
  margin-top: 4px;
}

/* ============================================================
   卡片网格
   ============================================================ */
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.card {
  position: relative;
  background: var(--surface-glass-strong);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  overflow: hidden;
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.card::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, rgba(79, 195, 247, 0.10), transparent 55%);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
  pointer-events: none;
}

.card:hover {
  transform: translateY(-6px);
  border-color: rgba(79, 195, 247, 0.45);
  box-shadow: var(--shadow-lg);
}

.card:hover::after {
  opacity: 1;
}

.card h3 {
  margin-top: 0;
  font-size: 18px;
}

.card svg {
  width: 100%;
  height: 120px;
  margin-bottom: 14px;
  border-radius: var(--radius-sm);
  transition: transform var(--dur) var(--ease);
}

.card:hover svg {
  transform: scale(1.03);
}

/* ============================================================
   文章列表
   ============================================================ */
.articles {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.article {
  position: relative;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  background: var(--surface-glass-strong);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.article::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  bottom: 18px;
  width: 3px;
  border-radius: var(--radius-pill);
  background: linear-gradient(180deg, var(--accent), transparent);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}

.article:hover {
  transform: translateY(-5px);
  border-color: rgba(79, 195, 247, 0.45);
  box-shadow: var(--shadow-lg);
}

.article:hover::before {
  opacity: 1;
}

.article h3 {
  font-size: 17px;
  margin: 0 0 8px;
  color: var(--brand-mid);
  line-height: 1.5;
  transition: color var(--dur) var(--ease);
}

.article:hover h3 {
  color: var(--brand-blue);
}

.article .meta {
  font-size: 13px;
  color: var(--text-faint);
  margin-bottom: 10px;
  letter-spacing: 0.2px;
}

.article p {
  font-size: 14px;
  color: var(--text-mute);
  margin-bottom: 14px;
  flex: 1;
}

.article a {
  align-self: flex-start;
  font-size: 14px;
  font-weight: 700;
  color: var(--brand-blue);
  padding: 4px 0;
  position: relative;
  transition: color var(--dur) var(--ease), letter-spacing var(--dur) var(--ease);
}

.article a::after {
  content: " →";
  display: inline-block;
  transition: transform var(--dur) var(--ease);
}

.article a:hover {
  color: var(--brand-deep);
  letter-spacing: 0.4px;
}

.article a:hover::after {
  transform: translateX(4px);
}

/* ============================================================
   FAQ 手风琴
   ============================================================ */
.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
  transition: border-color var(--dur) var(--ease);
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-q {
  font-weight: 700;
  color: var(--brand-mid);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  font-size: 16px;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.faq-q:hover {
  color: var(--brand-blue);
  background: rgba(79, 195, 247, 0.08);
}

.faq-q:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.faq-q span {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  font-size: 16px;
  font-weight: 400;
  color: var(--accent);
  background: rgba(79, 195, 247, 0.12);
  border: 1px solid rgba(79, 195, 247, 0.35);
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease);
}

.faq-item.open .faq-q span {
  background: var(--accent);
  color: var(--brand-dark);
  transform: rotate(180deg);
}

.faq-a {
  display: none;
  margin-top: 12px;
  padding: 0 8px;
  color: var(--text-mute);
  font-size: 15px;
  text-align: justify;
  animation: faqIn 0.4s var(--ease) both;
}

.faq-item.open .faq-a {
  display: block;
}

@keyframes faqIn {
  from {
    opacity: 0;
    transform: translateY(-6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================================
   HowTo 教程
   ============================================================ */
.howto ol {
  margin: 12px 0 12px 22px;
  color: var(--text-soft);
}

.howto ol li {
  margin-bottom: 10px;
  padding-left: 4px;
  transition: color var(--dur) var(--ease);
}

.howto ol li::marker {
  color: var(--brand-blue);
  font-weight: 700;
}

.howto ol li:hover {
  color: var(--brand-blue);
}

/* ============================================================
   表格
   ============================================================ */
table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 20px 0;
  font-size: 14px;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 0 0 1px var(--border);
}

th,
td {
  border-bottom: 1px solid var(--border);
  border-right: 1px solid var(--border);
  padding: 12px 14px;
  text-align: left;
  transition: background var(--dur) var(--ease);
}

th:last-child,
td:last-child {
  border-right: none;
}

tr:last-child td {
  border-bottom: none;
}

th {
  background: linear-gradient(135deg, rgba(79, 195, 247, 0.16), rgba(26, 95, 180, 0.10));
  color: var(--brand-mid);
  font-weight: 700;
  letter-spacing: 0.3px;
}

tbody tr {
  transition: background var(--dur) var(--ease);
}

tbody tr:hover {
  background: rgba(79, 195, 247, 0.07);
}

/* ============================================================
   页脚
   ============================================================ */
footer.site {
  position: relative;
  background:
    radial-gradient(circle at 8% 0%, rgba(79, 195, 247, 0.14), transparent 46%),
    radial-gradient(circle at 92% 100%, rgba(26, 95, 180, 0.18), transparent 50%),
    var(--brand-dark);
  color: #b9c7d9;
  padding: 48px 20px 22px;
  font-size: 14px;
  border-top: 1px solid rgba(79, 195, 247, 0.16);
}

.footer-wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

footer.site h3 {
  color: #fff;
  font-size: 16px;
  margin-bottom: 14px;
  padding-bottom: 8px;
  position: relative;
  letter-spacing: 0.4px;
}

footer.site h3::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 28px;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), transparent);
}

footer.site p {
  color: #93a6bd;
  line-height: 1.9;
}

footer.site ul {
  list-style: none;
}

footer.site li {
  margin-bottom: 9px;
  line-height: 1.7;
  transition: transform var(--dur) var(--ease);
}

footer.site li:hover {
  transform: translateX(4px);
}

footer.site a {
  color: #b9c7d9;
  transition: color var(--dur) var(--ease);
}

footer.site a:hover {
  color: var(--accent);
}

.copyright {
  max-width: var(--maxw);
  margin: 30px auto 0;
  border-top: 1px solid rgba(79, 195, 247, 0.14);
  padding-top: 18px;
  text-align: center;
  color: #7a8a9e;
  font-size: 13px;
  letter-spacing: 0.2px;
}

.copyright p {
  color: #7a8a9e;
}

/* ============================================================
   返回顶部
   ============================================================ */
#backTop {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-blue), var(--accent));
  color: #fff;
  border: none;
  font-size: 20px;
  cursor: pointer;
  display: none;
  z-index: 200;
  box-shadow: var(--shadow-glow);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    filter var(--dur) var(--ease);
}

#backTop:hover {
  transform: translateY(-4px) scale(1.05);
  filter: brightness(1.08);
  box-shadow: 0 12px 36px rgba(79, 195, 247, 0.5);
}

#backTop:active {
  transform: translateY(-1px) scale(0.98);
}

/* ============================================================
   滚动动画
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  will-change: opacity, transform;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ============================================================
   暗色模式
   ============================================================ */
body.dark {
  --bg: #0a1220;
  --bg-alt: #101d30;
  --surface: #101d30;
  --surface-glass: rgba(16, 29, 48, 0.72);
  --surface-glass-strong: rgba(21, 36, 58, 0.82);
  --border: #1e2f45;
  --border-glass: rgba(79, 195, 247, 0.14);

  --text: #c6d4e6;
  --text-soft: #a9b8cc;
  --text-mute: #8fa2ba;
  --text-faint: #6f829a;

  --link: #6cc4f5;
  --link-hover: #9adcff;

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.42);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.55);

  background: var(--bg);
  background-image:
    radial-gradient(circle at 12% -8%, rgba(79, 195, 247, 0.12), transparent 42%),
    radial-gradient(circle at 92% 4%, rgba(26, 95, 180, 0.16), transparent 46%);
  color: var(--text);
}

body.dark header.site {
  background: rgba(8, 16, 28, 0.88);
  border-bottom-color: rgba(79, 195, 247, 0.22);
}

body.dark section {
  background: var(--surface-glass);
  border-color: var(--border-glass);
  box-shadow: var(--shadow);
}

body.dark section h2 {
  color: #e6eef8;
}

body.dark section h3 {
  color: #c6d4e6;
}

body.dark section h4 {
  color: var(--accent);
}

body.dark section p {
  color: var(--text-soft);
}

body.dark .card,
body.dark .article {
  background: var(--surface-glass-strong);
  border-color: var(--border);
}

body.dark .article h3 {
  color: #d6e4f4;
}

body.dark .article:hover h3 {
  color: var(--accent);
}

body.dark .article p {
  color: var(--text-mute);
}

body.dark .stat {
  background: linear-gradient(150deg, rgba(79, 195, 247, 0.12), rgba(26, 95, 180, 0.06));
  border-color: rgba(79, 195, 247, 0.22);
}

body.dark .stat .num {
  color: var(--accent);
}

body.dark .stat .label {
  color: var(--text-mute);
}

body.dark .breadcrumb {
  color: var(--text-mute);
}

body.dark .breadcrumb span {
  color: var(--text-faint);
}

body.dark .faq-q {
  color: #d6e4f4;
}

body.dark .faq-q:hover {
  color: var(--accent);
  background: rgba(79, 195, 247, 0.10);
}

body.dark .faq-a {
  color: var(--text-soft);
}

body.dark .faq-item {
  border-bottom-color: var(--border);
}

body.dark table {
  box-shadow: 0 0 0 1px var(--border);
}

body.dark th {
  background: linear-gradient(135deg, rgba(79, 195, 247, 0.16), rgba(26, 95, 180, 0.14));
  color: #d6e4f4;
}

body.dark td {
  border-color: var(--border);
  color: var(--text-soft);
}

body.dark tbody tr:hover {
  background: rgba(79, 195, 247, 0.08);
}

body.dark .howto ol {
  color: var(--text-soft);
}

body.dark .howto ol li::marker {
  color: var(--accent);
}

body.dark footer.site {
  border-top-color: rgba(79, 195, 247, 0.18);
}

/* ============================================================
   响应式 - 平板
   ============================================================ */
@media (max-width: 1024px) {
  .nav-wrap {
    gap: 12px;
  }

  nav.main ul {
    gap: 2px;
  }

  nav.main a {
    font-size: 14px;
    padding: 6px 8px;
  }

  .search-box input[type="search"] {
    width: 130px;
  }

  .search-box input[type="search"]:focus {
    width: 160px;
  }

  .slides {
    height: 320px;
  }
}

/* ============================================================
   响应式 - 移动端 900px
   ============================================================ */
@media (max-width: 900px) {
  :root {
    --header-h: 60px;
  }

  .nav-wrap {
    padding: 0 16px;
  }

  /* 移动端导航抽屉 */
  nav.main {
    display: none;
  }

  nav.main.open {
    display: block;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: rgba(13, 27, 42, 0.97);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    padding: 16px 20px 20px;
    border-bottom: 1px solid rgba(79, 195, 247, 0.22);
    box-shadow: 0 18px 40px rgba(0, 0, 0, 0.4);
    animation: navDrop 0.3s var(--ease) both;
  }

  @keyframes navDrop {
    from {
      opacity: 0;
      transform: translateY(-10px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  nav.main.open ul {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
  }

  nav.main.open a {
    display: block;
    padding: 10px 12px;
    font-size: 15px;
    border-radius: var(--radius-sm);
  }

  nav.main.open a::after {
    display: none;
  }

  .menu-btn {
    display: inline-block;
  }

  .search-box input[type="search"] {
    width: 110px;
  }

  .search-box input[type="search"]:focus {
    width: 130px;
  }

  .search-box button {
    padding: 7px 12px;
  }

  .breadcrumb {
    padding: 14px 16px 0;
  }

  .banner {
    margin: 12px 16px 0;
    border-radius: var(--radius);
  }

  .slides {
    height: 300px;
  }

  .slide h2 {
    font-size: 26px;
  }

  .slide p {
    font-size: 15px;
  }

  main {
    padding: 0 16px 56px;
  }

  section {
    margin-top: 32px;
    padding: 26px 22px;
    border-radius: var(--radius);
  }

  section h2 {
    font-size: 21px;
    margin-bottom: 18px;
  }

  section h3 {
    font-size: 17px;
  }

  .stats,
  .grid,
  .articles,
  .footer-wrap {
    grid-template-columns: 1fr 1fr;
  }

  .footer-wrap {
    gap: 26px;
  }
}

/* ============================================================
   响应式 - 小屏 600px
   ============================================================ */
@media (max-width: 600px) {
  body {
    font-size: 15px;
  }

  .brand {
    font-size: 17px;
    gap: 8px;
  }

  .brand svg {
    width: 30px;
    height: 30px;
  }

  .search-box {
    gap: 6px;
  }

  .search-box input[type="search"] {
    width: 84px;
    padding: 6px 10px;
    font-size: 13px;
  }

  .search-box input[type="search"]:focus {
    width: 104px;
  }

  .search-box button,
  .theme-btn,
  .menu-btn {
    padding: 6px 10px;
    font-size: 13px;
  }

  .slides {
    height: 260px;
  }

  .slide {
    padding: 18px;
  }

  .slide h2 {
    font-size: 21px;
    margin-bottom: 10px;
  }

  .slide p {
    font-size: 14px;
  }

  .dots {
    bottom: 12px;
    padding: 6px 12px;
  }

  section {
    padding: 22px 18px;
    margin-top: 26px;
  }

  section h2 {
    font-size: 19px;
    padding-left: 14px;
  }

  section h2::before {
    height: 22px;
    width: 4px;
  }

  section h3 {
    font-size: 16px;
    margin-top: 20px;
  }

  section p {
    text-align: left;
  }

  .stats,
  .grid,
  .articles,
  .footer-wrap {
    grid-template-columns: 1fr;
  }

  .stat .num {
    font-size: 28px;
  }

  .card {
    padding: 18px;
  }

  .article {
    padding: 16px;
  }

  .faq-q {
    font-size: 15px;
    gap: 10px;
  }

  .faq-a {
    font-size: 14px;
  }

  /* 表格移动端横向滚动 */
  table {
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    white-space: nowrap;
  }

  th,
  td {
    padding: 10px 12px;
  }

  footer.site {
    padding: 36px 16px 18px;
  }

  #backTop {
    right: 16px;
    bottom: 16px;
    width: 44px;
    height: 44px;
    font-size: 18px;
  }
}

/* ============================================================
   减少动效偏好
   ============================================================ */
@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;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ============================================================
   打印样式
   ============================================================ */
@media print {
  header.site,
  footer.site,
  #backTop,
  .dots,
  .search-box,
  .menu-btn,
  .theme-btn {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
  }

  section {
    box-shadow: none;
    border: 1px solid #ccc;
    break-inside: avoid;
  }

  a {
    color: #000;
  }
}
```