```css
/* ===== 设计规范与变量 ===== */
:root {
  --brand: #0b5e7a;
  --brand-dark: #083d4f;
  --brand-light: #1b8a9e;
  --accent: #f0a500;
  --accent-rgb: 240, 165, 0;
  --text-primary: #1F2937;
  --text-secondary: #243447;
  --text-muted: #5b6b7b;
  --bg-body: #ffffff;
  --bg-soft: #f0f4f8;
  --bg-card: #ffffff;
  --bg-input: #eef2f6;
  --border-light: #e2e8f0;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.08);
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 999px;
  --transition-fast: 0.2s ease;
  --transition-slow: 0.4s cubic-bezier(0.25, 0.1, 0.25, 1);
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(255, 255, 255, 0.3);
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
}

/* ===== 暗色模式变量覆盖 ===== */
body.dark-mode {
  --brand: #4db8d4;
  --brand-dark: #a3d9f0;
  --brand-light: #6ec1e0;
  --accent: #ffb347;
  --text-primary: #E2E8F0;
  --text-secondary: #D1D9E6;
  --text-muted: #94a3b8;
  --bg-body: #0B1117;
  --bg-soft: #0F1A24;
  --bg-card: #1A2530;
  --bg-input: #1F2A36;
  --border-light: #2D3E4F;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.4);
  --glass-bg: rgba(26, 37, 48, 0.6);
  --glass-border: rgba(255, 255, 255, 0.1);
}

/* ===== 基础重置与全局 ===== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.75;
  font-size: 16px;
  transition: background-color 0.4s ease, color 0.3s ease;
  overflow-x: hidden;
}

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

a {
  color: var(--brand);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--brand-dark);
}

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

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 650;
  line-height: 1.3;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

p {
  color: var(--text-secondary);
}

/* ===== 文本工具 ===== */
.text-muted {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.text-center {
  text-align: center;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-block;
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #ffffff;
  padding: 0.8rem 2.2rem;
  border-radius: var(--radius-full);
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: transform 0.3s ease, box-shadow 0.3s ease, filter 0.3s ease;
  box-shadow: 0 4px 15px rgba(11, 94, 122, 0.3);
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.25), transparent);
  transition: left 0.5s ease;
}

.btn:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 8px 30px rgba(11, 94, 122, 0.4);
}

.btn:hover::before {
  left: 100%;
}

.btn:active {
  transform: translateY(-1px) scale(0.98);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--brand);
  color: var(--brand-dark);
  box-shadow: none;
}

.btn-outline:hover {
  background: rgba(11, 94, 122, 0.08);
  box-shadow: none;
  color: var(--brand-dark);
}

body.dark-mode .btn-outline {
  color: var(--brand-dark);
  border-color: var(--brand-light);
}

body.dark-mode .btn-outline:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* ===== 头部导航 ===== */
.site-header {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--glass-border);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow-sm);
  transition: background 0.3s ease, box-shadow 0.3s ease;
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.8rem 2rem;
  gap: 1rem;
}

.logo {
  font-size: 1.6rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--brand), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
  white-space: nowrap;
}

.logo span {
  background: none;
  -webkit-text-fill-color: var(--accent);
}

.nav-links {
  display: flex;
  gap: 1.8rem;
  align-items: center;
}

.nav-links a {
  font-weight: 500;
  color: var(--text-secondary);
  font-size: 1rem;
  position: relative;
  transition: color 0.2s ease;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--brand);
  transition: width 0.3s ease;
}

.nav-links a:hover {
  color: var(--brand);
}

.nav-links a:hover::after {
  width: 100%;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.search-box {
  display: flex;
  background: var(--bg-input);
  border-radius: var(--radius-full);
  padding: 0.2rem 0.2rem 0.2rem 1rem;
  align-items: center;
  transition: box-shadow 0.3s ease, background 0.3s ease;
  border: 1px solid transparent;
}

.search-box:focus-within {
  box-shadow: 0 0 0 3px rgba(11, 94, 122, 0.2);
  background: var(--bg-card);
  border-color: var(--brand);
}

.search-box input {
  border: none;
  background: transparent;
  padding: 0.5rem;
  width: 160px;
  color: var(--text-primary);
  outline: none;
  font-size: 0.9rem;
}

.search-box input::placeholder {
  color: var(--text-muted);
}

.search-box button {
  background: var(--brand);
  border: none;
  border-radius: var(--radius-full);
  padding: 0.5rem 1rem;
  color: #fff;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.3s ease;
}

.search-box button:hover {
  background: var(--brand-light);
}

.dark-toggle {
  background: var(--bg-input);
  border: none;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--text-primary);
  transition: background 0.3s ease, transform 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

.dark-toggle:hover {
  transform: rotate(20deg) scale(1.1);
  background: var(--bg-card);
}

/* ===== Hero 主视觉 ===== */
.hero {
  background: linear-gradient(135deg, #e0f2fe 0%, #f0f9ff 40%, #ffffff 100%);
  padding: 4rem 2rem;
  position: relative;
  overflow: hidden;
}

body.dark-mode .hero {
  background: linear-gradient(135deg, #0c1b2a, #0f1a24 60%, #0b1117);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 60%;
  height: 200%;
  background: radial-gradient(circle, rgba(11, 94, 122, 0.08) 0%, transparent 70%);
  pointer-events: none;
}

.hero-content {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 3rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  margin-bottom: 1.2rem;
  line-height: 1.2;
  background: linear-gradient(135deg, var(--text-primary), var(--brand));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  max-width: 560px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.hero-stats {
  display: flex;
  gap: 2.5rem;
  margin-top: 2.5rem;
  flex-wrap: wrap;
}

.stat-item {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 800;
  background: linear-gradient(135deg, var(--brand), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}

.stat-item + p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 0.2rem;
}

.hero-visual {
  position: relative;
}

.video-card {
  background: var(--glass-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
  transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.video-card:hover {
  transform: translateY(-8px) rotate(1deg);
  box-shadow: 0 20px 50px rgba(11, 94, 122, 0.15);
}

.video-svg {
  width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #e6f0f9, #d4e6f5);
  transition: transform 0.5s ease;
}

.video-card:hover .video-svg {
  transform: scale(1.02);
}

.video-card p {
  margin-top: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* ===== 通用区块 ===== */
.section {
  max-width: 1280px;
  margin: 4rem auto;
  padding: 0 2rem;
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 700;
  margin-bottom: 2.5rem;
  position: relative;
  padding-left: 1.2rem;
}

.section-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.3rem;
  width: 5px;
  height: 80%;
  background: linear-gradient(to bottom, var(--brand), var(--accent));
  border-radius: 4px;
}

/* ===== 品牌介绍 & 公司信息 ===== */
.brand-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.brand-history,
.company-info {
  background: var(--bg-card);
  padding: 2rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  backdrop-filter: blur(8px);
}

.brand-history:hover,
.company-info:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}

body.dark-mode .brand-history,
body.dark-mode .company-info {
  background: var(--bg-card);
  border-color: var(--border-light);
}

.company-info ul {
  list-style: none;
  margin: 1rem 0;
}

.company-info li {
  padding: 0.4rem 0;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.company-info li::before {
  content: '✓';
  color: var(--brand);
  font-weight: bold;
}

/* ===== 视频展示区 ===== */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.video-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 1.2rem;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  transition: transform 0.4s ease, box-shadow 0.4s ease, border-color 0.3s ease;
  overflow: hidden;
  position: relative;
}

.video-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.05), transparent 50%);
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
}

.video-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-lg);
  border-color: var(--brand-light);
}

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

.video-card svg {
  border-radius: var(--radius-md);
  width: 100%;
  height: auto;
  transition: transform 0.5s ease;
}

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

.video-card h3 {
  margin-top: 1rem;
  font-size: 1.2rem;
  font-weight: 600;
}

.video-card .text-muted {
  font-size: 0.85rem;
}

/* ===== 文章卡片 ===== */
.grid-articles {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.8rem;
}

.article-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  border: 1px solid var(--border-light);
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
  position: relative;
  overflow: hidden;
}

.article-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: linear-gradient(to bottom, var(--brand), var(--accent));
  opacity: 0;
  transition: opacity 0.3s ease;
}

.article-card:hover {
  transform: translateY(-5px) scale(1.01);
  box-shadow: var(--shadow-md);
  border-color: var(--brand-light);
}

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

.article-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
  transition: color 0.2s ease;
}

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

.article-card .meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.8rem;
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.article-card p {
  font-size: 0.95rem;
  margin-bottom: 1rem;
  color: var(--text-secondary);
}

.article-card a {
  font-weight: 500;
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  transition: gap 0.2s ease;
}

.article-card a:hover {
  gap: 0.6rem;
}

/* ===== FAQ 手风琴 ===== */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 0;
  transition: box-shadow 0.3s ease, border-color 0.3s ease;
  overflow: hidden;
  backdrop-filter: blur(4px);
}

.faq-item:hover {
  border-color: var(--brand-light);
  box-shadow: var(--shadow-sm);
}

.faq-question {
  font-weight: 600;
  font-size: 1.1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  padding: 1.2rem 1.5rem;
  user-select: none;
  transition: background 0.3s ease;
}

.faq-question:hover {
  background: rgba(11, 94, 122, 0.05);
}

.faq-question span {
  font-size: 1.5rem;
  color: var(--brand);
  transition: transform 0.3s ease;
  flex-shrink: 0;
  margin-left: 1rem;
}

.faq-question.open span {
  transform: rotate(45deg);
}

.faq-answer {
  padding: 0 1.5rem;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease, opacity 0.3s ease;
  opacity: 0;
  color: var(--text-secondary);
  font-size: 0.98rem;
  line-height: 1.7;
}

.faq-answer.show {
  max-height: 500px;
  padding: 0 1.5rem 1.2rem;
  opacity: 1;
}

/* ===== HowTo 教程区 ===== */
.howto-box {
  background: var(--bg-card);
  padding: 2.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(8px);
}

body.dark-mode .howto-box {
  background: var(--bg-card);
  border-color: var(--border-light);
}

.howto-step {
  display: flex;
  gap: 1.2rem;
  margin-bottom: 1.6rem;
  align-items: flex-start;
  opacity: 0;
  transform: translateX(-20px);
  animation: slideIn 0.6s ease forwards;
}

.howto-step:nth-child(1) { animation-delay: 0.1s; }
.howto-step:nth-child(2) { animation-delay: 0.2s; }
.howto-step:nth-child(3) { animation-delay: 0.3s; }
.howto-step:nth-child(4) { animation-delay: 0.4s; }
.howto-step:nth-child(5) { animation-delay: 0.5s; }
.howto-step:nth-child(6) { animation-delay: 0.6s; }
.howto-step:nth-child(7) { animation-delay: 0.7s; }

@keyframes slideIn {
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.step-num {
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #fff;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(11, 94, 122, 0.3);
}

.howto-step p {
  flex: 1;
  color: var(--text-secondary);
}

/* ===== 联系方式 & 承诺区 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  background: var(--bg-card);
  padding: 2.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(8px);
}

.contact-grid h3 {
  margin-bottom: 1rem;
  font-size: 1.3rem;
}

.contact-grid p {
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--bg-soft);
  padding: 3rem 2rem 2rem;
  margin-top: 4rem;
  border-top: 1px solid var(--border-light);
  transition: background 0.3s ease;
}

body.dark-mode .site-footer {
  background: var(--bg-soft);
  border-top-color: var(--border-light);
}

.footer-grid {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem;
}

.footer-grid h4 {
  margin-bottom: 1rem;
  font-size: 1.1rem;
}

.footer-grid a {
  color: var(--text-secondary);
  text-decoration: none;
  display: block;
  margin-bottom: 0.5rem;
  transition: color 0.2s ease, padding-left 0.2s ease;
  font-size: 0.95rem;
}

.footer-grid a:hover {
  color: var(--brand);
  padding-left: 5px;
}

.footer-bottom {
  border-top: 1px solid var(--border-light);
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
  max-width: 1280px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== 返回顶部按钮 ===== */
.scroll-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #fff;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  cursor: pointer;
  border: none;
  z-index: 999;
  box-shadow: 0 4px 15px rgba(11, 94, 122, 0.4);
  transition: transform 0.3s ease, box-shadow 0.3s ease, opacity 0.3s ease;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
}

.scroll-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.scroll-top:hover {
  transform: translateY(-5px) scale(1.1);
  box-shadow: 0 8px 25px rgba(11, 94, 122, 0.5);
}

/* ===== 滚动动画 ===== */
[data-animate] {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-animate].animate-in {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 响应式适配 ===== */
@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .brand-grid {
    grid-template-columns: 1fr;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

@media (max-width: 900px) {
  .nav-container {
    flex-wrap: wrap;
    padding: 0.8rem 1rem;
    gap: 0.5rem;
  }

  .nav-links {
    order: 3;
    width: 100%;
    justify-content: center;
    margin-top: 0.5rem;
    flex-wrap: wrap;
    gap: 1rem;
  }

  .nav-actions {
    margin-left: auto;
  }

  .search-box input {
    width: 120px;
  }

  .hero {
    padding: 3rem 1rem;
  }

  .hero-stats {
    gap: 1.5rem;
  }

  .section {
    padding: 0 1rem;
    margin: 3rem auto;
  }

  .video-grid {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
  }

  .grid-articles {
    grid-template-columns: 1fr;
  }

  .howto-box {
    padding: 1.5rem;
  }

  .contact-grid {
    padding: 1.5rem;
  }
}

@media (max-width: 600px) {
  .logo {
    font-size: 1.3rem;
  }

  .nav-actions {
    width: 100%;
    justify-content: space-between;
    margin-top: 0.3rem;
  }

  .search-box {
    flex: 1;
    max-width: 100%;
  }

  .search-box input {
    width: 100%;
    flex: 1;
  }

  .dark-toggle {
    width: 38px;
    height: 38px;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .btn {
    padding: 0.7rem 1.5rem;
    font-size: 0.9rem;
  }

  .hero-stats {
    flex-direction: column;
    gap: 0.8rem;
  }

  .section-title {
    font-size: 1.4rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .scroll-top {
    bottom: 1.5rem;
    right: 1.5rem;
    width: 42px;
    height: 42px;
    font-size: 1.2rem;
  }

  .faq-question {
    font-size: 1rem;
    padding: 1rem;
  }

  .faq-answer {
    padding: 0 1rem;
  }

  .faq-answer.show {
    padding: 0 1rem 1rem;
  }
}

/* ===== 暗色模式微调 ===== */
body.dark-mode .search-box {
  background: var(--bg-input);
}

body.dark-mode .search-box input {
  color: var(--text-primary);
}

body.dark-mode .dark-toggle {
  background: var(--bg-input);
  color: var(--text-primary);
}

body.dark-mode .video-card,
body.dark-mode .article-card,
body.dark-mode .faq-item {
  background: var(--bg-card);
  border-color: var(--border-light);
}

/* ===== 打印样式 ===== */
@media print {
  .site-header,
  .site-footer,
  .scroll-top,
  .dark-toggle,
  .search-box,
  .hero-actions {
    display: none !important;
  }

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

  .section {
    margin: 1rem auto;
  }
}

/* ===== 动画关键帧 ===== */
@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

@keyframes float {
  0%, 100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-10px);
  }
}

@keyframes shimmer {
  0% {
    background-position: -1000px 0;
  }
  100% {
    background-position: 1000px 0;
  }
}

/* ===== 滚动条美化 ===== */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-soft);
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(to bottom, var(--brand), var(--brand-light));
  border-radius: 8px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--brand-dark);
}

/* ===== 焦点可见性 ===== */
:focus-visible {
  outline: 3px solid rgba(11, 94, 122, 0.5);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ===== 暗色模式过渡 ===== */
body,
.site-header,
.site-footer,
.video-card,
.article-card,
.faq-item,
.search-box,
.dark-toggle,
.btn,
.btn-outline {
  transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}
```