:root {
  --bg: #f7f8fc;
  --bg-gradient: linear-gradient(135deg, #fdf2f4 0%, #eef4fb 50%, #f7f8fc 100%);
  --surface: #ffffff;
  --surface-glass: rgba(255, 255, 255, 0.72);
  --text: #1a1a2e;
  --text-secondary: #5a5a72;
  --border: #e4e6f0;
  --border-glass: rgba(255, 255, 255, 0.5);
  --brand: #e63946;
  --brand-soft: #fde8ea;
  --brand-dark: #b82a36;
  --brand-glow: rgba(230, 57, 70, 0.35);
  --accent: #457b9d;
  --accent-soft: #e8f0f8;
  --accent-glow: rgba(69, 123, 157, 0.25);
  --shadow: 0 8px 32px rgba(26, 26, 46, 0.08);
  --shadow-hover: 0 16px 48px rgba(26, 26, 46, 0.14);
  --radius: 20px;
  --radius-sm: 12px;
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="dark"] {
  --bg: #0f0f1a;
  --bg-gradient: linear-gradient(135deg, #1a1020 0%, #0f1520 50%, #0f0f1a 100%);
  --surface: #1a1a2e;
  --surface-glass: rgba(26, 26, 46, 0.72);
  --text: #ececf4;
  --text-secondary: #a8a8c0;
  --border: #2a2a42;
  --border-glass: rgba(255, 255, 255, 0.08);
  --brand: #f25c6a;
  --brand-soft: #2e1820;
  --brand-dark: #d94856;
  --brand-glow: rgba(242, 92, 106, 0.3);
  --accent: #6a9ec0;
  --accent-soft: #16222e;
  --accent-glow: rgba(106, 158, 192, 0.2);
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  --shadow-hover: 0 16px 48px rgba(0, 0, 0, 0.55);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-sans);
  background: var(--bg);
  background-image: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text);
  line-height: 1.75;
  transition: background var(--transition), color var(--transition);
  padding-top: 72px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition);
}

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

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
}

/* ========== 导航吸顶 ========== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border-glass);
  transition: background var(--transition), border var(--transition), box-shadow var(--transition);
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.35rem;
  color: var(--brand);
  flex-shrink: 0;
  letter-spacing: -0.02em;
  transition: transform var(--transition);
}

.logo:hover {
  transform: scale(1.03);
  color: var(--brand);
}

.logo svg {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  box-shadow: 0 4px 12px var(--brand-glow);
  transition: box-shadow var(--transition);
}

.logo:hover svg {
  box-shadow: 0 6px 20px var(--brand-glow);
}

.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
  font-size: 0.95rem;
  font-weight: 500;
}

.nav-links a {
  color: var(--text-secondary);
  position: relative;
  padding: 4px 0;
}

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  border-radius: 2px;
  transition: width var(--transition);
}

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

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.search-box {
  display: flex;
  align-items: center;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 40px;
  padding: 4px 4px 4px 16px;
  transition: border var(--transition), box-shadow var(--transition);
}

.search-box:focus-within {
  border-color: var(--brand);
  box-shadow: 0 0 0 4px var(--brand-soft);
}

.search-box input {
  border: none;
  background: transparent;
  padding: 8px 0;
  font-size: 0.9rem;
  color: var(--text);
  outline: none;
  width: 160px;
  font-family: inherit;
}

.search-box input::placeholder {
  color: var(--text-secondary);
  opacity: 0.7;
}

.search-box button {
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  border: none;
  color: #fff;
  border-radius: 40px;
  padding: 8px 18px;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  transition: transform var(--transition), box-shadow var(--transition), filter var(--transition);
}

.search-box button:hover {
  transform: scale(1.04);
  box-shadow: 0 4px 16px var(--brand-glow);
  filter: brightness(1.05);
}

.search-box button:active {
  transform: scale(0.97);
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text);
  transition: background var(--transition), border var(--transition), transform var(--transition), box-shadow var(--transition);
}

.theme-toggle:hover {
  background: var(--brand-soft);
  border-color: var(--brand);
  transform: rotate(20deg) scale(1.08);
  box-shadow: 0 4px 14px var(--brand-glow);
}

.theme-toggle svg {
  transition: transform var(--transition);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.6rem;
  cursor: pointer;
  color: var(--text);
  padding: 4px;
  line-height: 1;
}

/* ========== 移动菜单 ========== */
.mobile-menu {
  display: none;
  position: fixed;
  top: 72px;
  left: 0;
  right: 0;
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border-glass);
  padding: 20px 24px;
  z-index: 999;
  flex-direction: column;
  gap: 4px;
  box-shadow: var(--shadow);
  animation: slideDown 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.mobile-menu.open {
  display: flex;
}

.mobile-menu a {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  transition: color var(--transition), padding-left var(--transition);
}

.mobile-menu a:last-child {
  border-bottom: none;
}

.mobile-menu a:hover {
  color: var(--brand);
  padding-left: 8px;
}

/* ========== 主体容器 ========== */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ========== 面包屑 ========== */
.breadcrumb {
  padding: 16px 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
}

.breadcrumb li + li::before {
  content: "›";
  margin: 0 6px;
  color: var(--border);
}

.breadcrumb a {
  color: var(--text-secondary);
}

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

/* ========== 首屏 Hero ========== */
.hero {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  padding: 48px 0 64px;
  position: relative;
}

.hero::before {
  content: "";
  position: absolute;
  top: -80px;
  left: -120px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, var(--brand-soft) 0%, transparent 70%);
  border-radius: 50%;
  z-index: -1;
  pointer-events: none;
  opacity: 0.8;
}

.hero::after {
  content: "";
  position: absolute;
  bottom: -60px;
  right: -100px;
  width: 360px;
  height: 360px;
  background: radial-gradient(circle, var(--accent-soft) 0%, transparent 70%);
  border-radius: 50%;
  z-index: -1;
  pointer-events: none;
  opacity: 0.8;
}

.hero-content h1 {
  font-size: 2.8rem;
  line-height: 1.25;
  font-weight: 800;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
  animation: heroFadeIn 0.8s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.hero-content h1 span {
  background: linear-gradient(135deg, var(--brand), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.hero-content p {
  font-size: 1.08rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 520px;
  animation: heroFadeIn 0.8s cubic-bezier(0.16, 1, 0.3, 1) 0.15s both;
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  animation: heroFadeIn 0.8s cubic-bezier(0.16, 1, 0.3, 1) 0.3s both;
}

@keyframes heroFadeIn {
  from {
    opacity: 0;
    transform: translateY(28px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 1rem;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition), border-color var(--transition), color var(--transition);
  border: 2px solid transparent;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.25), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}

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

.btn-primary {
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  color: #fff;
  border-color: transparent;
  box-shadow: 0 6px 20px var(--brand-glow);
}

.btn-primary:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 12px 32px var(--brand-glow);
  color: #fff;
}

.btn-primary:active {
  transform: translateY(-1px) scale(0.99);
}

.btn-outline {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  color: var(--text);
  border-color: var(--border);
}

.btn-outline:hover {
  border-color: var(--brand);
  color: var(--brand);
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
  animation: heroFadeIn 0.9s cubic-bezier(0.16, 1, 0.3, 1) 0.2s both;
}

.hero-visual svg {
  width: 100%;
  max-width: 480px;
  filter: drop-shadow(0 24px 48px rgba(26, 26, 46, 0.12));
  transition: transform var(--transition-slow);
}

.hero-visual svg:hover {
  transform: translateY(-8px) scale(1.02);
}

/* ========== 数据统计 ========== */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  padding: 40px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  margin-bottom: 64px;
}

.stat-item {
  text-align: center;
  padding: 16px 8px;
  border-radius: var(--radius-sm);
  transition: background var(--transition), transform var(--transition);
}

.stat-item:hover {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  transform: translateY(-4px);
}

.stat-number {
  font-size: 2.4rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--brand), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  line-height: 1.2;
  letter-spacing: -0.03em;
}

.stat-label {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ========== 通用区块 ========== */
.section {
  padding: 64px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-header h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
  position: relative;
  display: inline-block;
}

.section-header h2::after {
  content: "";
  display: block;
  width: 56px;
  height: 4px;
  margin: 14px auto 0;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  border-radius: 4px;
}

.section-header p {
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto;
  font-size: 1.05rem;
}

/* ========== 卡片网格 ========== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 28px;
}

.card {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  backdrop-filter: blur(16px) saturate(160%);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  padding: 32px 28px;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition), background var(--transition);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.card:hover::before {
  transform: scaleX(1);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--brand-soft);
}

.card-icon {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--brand-soft), var(--accent-soft));
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--brand);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover .card-icon {
  transform: scale(1.1) rotate(-4deg);
  box-shadow: 0 8px 20px var(--brand-glow);
}

.card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
}

/* ========== 文章列表 ========== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 28px;
}

.article-card {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  backdrop-filter: blur(16px) saturate(160%);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--brand-soft);
}

.article-thumb {
  width: 100%;
  height: 180px;
  background: linear-gradient(135deg, var(--brand-soft) 0%, var(--accent-soft) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  position: relative;
  transition: transform var(--transition-slow);
}

.article-card:hover .article-thumb {
  transform: scale(1.02);
}

.article-thumb svg {
  transition: transform var(--transition-slow);
}

.article-card:hover .article-thumb svg {
  transform: scale(1.12) rotate(3deg);
}

.article-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.article-meta {
  display: flex;
  gap: 16px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 10px;
}

.article-meta span {
  color: var(--accent);
  font-weight: 500;
}

.article-body h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 10px;
  line-height: 1.45;
  letter-spacing: -0.01em;
  transition: color var(--transition);
}

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

.article-body p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  flex: 1;
}

.read-more {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--brand);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: gap var(--transition), color var(--transition);
  margin-top: auto;
}

.read-more:hover {
  gap: 10px;
  color: var(--brand-dark);
}

/* ========== FAQ ========== */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  backdrop-filter: blur(16px) saturate(160%);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.faq-item:hover {
  border-color: var(--brand-soft);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.04);
}

.faq-item.open {
  border-color: var(--brand);
  box-shadow: 0 8px 24px var(--brand-glow);
}

.faq-question {
  padding: 20px 24px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
  transition: background var(--transition), color var(--transition);
  gap: 16px;
}

.faq-question:hover {
  background: var(--brand-soft);
}

.faq-item.open .faq-question {
  color: var(--brand);
}

.faq-question .arrow {
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  font-size: 1.2rem;
  color: var(--text-secondary);
  flex-shrink: 0;
}

.faq-item.open .faq-question .arrow {
  transform: rotate(180deg);
  color: var(--brand);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.45s cubic-bezier(0.4, 0, 0.2, 1), padding 0.3s ease, opacity 0.3s ease;
  padding: 0 24px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.75;
  opacity: 0;
}

.faq-item.open .faq-answer {
  max-height: 500px;
  padding: 0 24px 22px;
  opacity: 1;
}

/* ========== HowTo ========== */
.howto-steps {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 24px;
  margin-top: 32px;
}

.step {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  backdrop-filter: blur(16px) saturate(160%);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-sm);
  padding: 28px 24px;
  position: relative;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
  overflow: hidden;
}

.step::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.step:hover {
  border-color: var(--brand);
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.step:hover::after {
  transform: scaleX(1);
}

.step-number {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 16px;
  box-shadow: 0 4px 12px var(--brand-glow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.step:hover .step-number {
  transform: scale(1.12) rotate(-8deg);
  box-shadow: 0 6px 20px var(--brand-glow);
}

.step h4 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.step p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ========== 表格 ========== */
.table-wrap {
  overflow-x: auto;
  margin-top: 32px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}

th, td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  background: linear-gradient(135deg, var(--brand-soft), var(--accent-soft));
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
}

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

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

tbody tr:hover {
  background: var(--brand-soft);
}

/* ========== 联系信息 ========== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 24px;
  margin-top: 32px;
}

.contact-item {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  backdrop-filter: blur(16px) saturate(160%);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-sm);
  padding: 24px;
  display: flex;
  align-items: flex-start;
  gap: 16px;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.contact-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
  border-color: var(--accent);
}

.contact-icon {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent-soft), var(--brand-soft));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  flex-shrink: 0;
  transition: transform var(--transition), background var(--transition);
}

.contact-item:hover .contact-icon {
  transform: scale(1.1);
  background: linear-gradient(135deg, var(--brand-soft), var(--accent-soft));
}

.contact-item h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.contact-item p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  word-break: break-word;
}

/* ========== 页脚 ========== */
.site-footer {
  background: var(--surface-glass);
  -webkit-backdrop-filter: blur(20px) saturate(160%);
  backdrop-filter: blur(20px) saturate(160%);
  border-top: 1px solid var(--border-glass);
  padding: 48px 0 24px;
  margin-top: 64px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 12px;
  max-width: 320px;
  line-height: 1.7;
}

.footer-col h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 16px;
  position: relative;
  display: inline-block;
}

.footer-col h4::after {
  content: "";
  display: block;
  width: 24px;
  height: 2px;
  margin-top: 8px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  border-radius: 2px;
}

.footer-col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col a {
  font-size: 0.88rem;
  color: var(--text-secondary);
  transition: color var(--transition), padding-left var(--transition);
  display: inline-block;
}

.footer-col a:hover {
  color: var(--brand);
  padding-left: 6px;
}

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.footer-bottom a {
  color: var(--text-secondary);
}

.footer-bottom a:hover {
  color: var(--brand);
}

/* ========== 返回顶部 ========== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  color: #fff;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 6px 20px var(--brand-glow);
  z-index: 900;
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-5px) scale(1.08);
  box-shadow: 0 12px 32px var(--brand-glow);
}

.back-to-top:active {
  transform: translateY(-2px) scale(1.02);
}

/* ========== 滚动动画 ========== */
.fade-in {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1), transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
  will-change: opacity, transform;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========== 选择文本 ========== */
::selection {
  background: var(--brand);
  color: #fff;
}

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

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

::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, var(--brand), var(--accent));
  border-radius: 10px;
  border: 2px solid var(--bg);
}

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

/* ========== 响应式 - 1024px ========== */
@media (max-width: 1024px) {
  .hero {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 32px;
  }

  .hero-content p {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .hero-visual svg {
    max-width: 380px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }

  .card-grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }
}

/* ========== 响应式 - 768px ========== */
@media (max-width: 768px) {
  body {
    padding-top: 64px;
  }

  .nav-links,
  .search-box {
    display: none;
  }

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

  .header-inner {
    height: 64px;
    padding: 0 16px;
  }

  .mobile-menu {
    top: 64px;
  }

  .logo {
    font-size: 1.15rem;
  }

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

  .hero {
    padding: 32px 0 48px;
  }

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

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

  .hero-visual svg {
    max-width: 300px;
  }

  .stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    padding: 28px 0;
    margin-bottom: 40px;
  }

  .stat-number {
    font-size: 1.9rem;
  }

  .container {
    padding: 0 16px;
  }

  .section {
    padding: 40px 0;
  }

  .section-header {
    margin-bottom: 32px;
  }

  .section-header h2 {
    font-size: 1.6rem;
  }

  .section-header p {
    font-size: 0.95rem;
  }

  .card-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .card {
    padding: 24px 22px;
  }

  .article-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .howto-steps {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .contact-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
  }

  .btn {
    padding: 12px 26px;
    font-size: 0.95rem;
  }

  .faq-question {
    padding: 16px 18px;
    font-size: 0.95rem;
  }

  .faq-answer {
    padding: 0 18px;
    font-size: 0.9rem;
  }

  .faq-item.open .faq-answer {
    padding: 0 18px 18px;
  }

  th, td {
    padding: 12px 14px;
    font-size: 0.85rem;
  }

  .hero::before,
  .hero::after {
    display: none;
  }
}

/* ========== 响应式 - 480px ========== */
@media (max-width: 480px) {
  .stats {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .stat-item {
    padding: 12px 8px;
  }

  .hero-content h1 {
    font-size: 1.7rem;
  }

  .hero-content p {
    font-size: 0.95rem;
  }

  .hero-cta {
    flex-direction: column;
    width: 100%;
  }

  .hero-cta .btn {
    width: 100%;
  }

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

  .article-thumb {
    height: 150px;
  }

  .section-header h2 {
    font-size: 1.4rem;
  }

  .footer-brand p {
    max-width: 100%;
  }

  .contact-item {
    padding: 18px;
  }

  .step {
    padding: 22px 18px;
  }
}

/* ========== 无障碍 & 减少动画 ========== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .fade-in {
    opacity: 1;
    transform: none;
  }
}

/* ========== 打印样式 ========== */
@media print {
  .site-header,
  .mobile-menu,
  .back-to-top,
  .hero-visual,
  .search-box,
  .theme-toggle {
    display: none !important;
  }

  body {
    padding-top: 0;
    background: #fff;
    color: #000;
  }

  .card,
  .article-card,
  .faq-item,
  .step,
  .contact-item {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ccc;
  }
}

/* ========== 焦点可见性 ========== */
:focus-visible {
  outline: 3px solid var(--brand);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ========== 卡片内列表样式修正 ========== */
.card ul {
  list-style: none;
}

.card ul li a {
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: color var(--transition), padding-left var(--transition);
  display: inline-block;
}

.card ul li a:hover {
  color: var(--brand);
  padding-left: 6px;
}