:root {
  --brand-dark: #0b1a2f;
  --brand-primary: #1e3a5f;
  --brand-accent: #e6b800;
  --brand-light: #f5f7fa;
  --brand-text: #1e2a3a;
  --brand-muted: #5b6f82;
  --brand-border: #dce3eb;
  --brand-white: #ffffff;
  --brand-glass: rgba(255, 255, 255, 0.72);
  --brand-glass-border: rgba(255, 255, 255, 0.35);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 16px 48px rgba(11, 26, 47, 0.14);
  --radius: 12px;
  --radius-lg: 20px;
  --transition: 0.28s cubic-bezier(0.34, 1.2, 0.64, 1);
  --font-stack: system-ui, -apple-system, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
}

body.dark-mode {
  --brand-dark: #e8edf2;
  --brand-primary: #a8c0d8;
  --brand-accent: #f0c94a;
  --brand-light: #0f1419;
  --brand-text: #e2e8f0;
  --brand-muted: #94a3b8;
  --brand-border: #2d3748;
  --brand-white: #1a202c;
  --brand-glass: rgba(26, 32, 44, 0.72);
  --brand-glass-border: rgba(148, 163, 184, 0.18);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.55);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-stack);
  color: var(--brand-text);
  background-color: var(--brand-light);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background-color 0.4s ease, color 0.4s ease;
}

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

a {
  -webkit-tap-highlight-color: transparent;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== 顶部导航 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--brand-glass);
  backdrop-filter: blur(18px) saturate(1.6);
  -webkit-backdrop-filter: blur(18px) saturate(1.6);
  border-bottom: 1px solid var(--brand-glass-border);
  box-shadow: var(--shadow-sm);
  transition: background 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--brand-text);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.5px;
  transition: transform var(--transition);
}

.logo:hover {
  transform: scale(1.03);
}

.logo svg {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
  border-radius: 10px;
  box-shadow: 0 4px 12px rgba(30, 58, 95, 0.25);
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--brand-border);
  border-radius: 10px;
  padding: 6px 10px;
  cursor: pointer;
  color: var(--brand-text);
  font-size: 1.2rem;
  line-height: 1;
  transition: all var(--transition);
}

.nav-toggle:hover {
  border-color: var(--brand-primary);
  color: var(--brand-primary);
}

.main-nav ul {
  display: flex;
  list-style: none;
  gap: 4px;
  align-items: center;
}

.main-nav a {
  text-decoration: none;
  color: var(--brand-muted);
  font-size: 0.92rem;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: 10px;
  transition: color var(--transition), background-color var(--transition), transform var(--transition);
  white-space: nowrap;
  position: relative;
}

.main-nav a::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 4px;
  height: 2px;
  background: var(--brand-accent);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.main-nav a:hover,
.main-nav a:focus-visible {
  color: var(--brand-primary);
  background-color: rgba(30, 58, 95, 0.07);
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.theme-btn,
.search-btn {
  background: var(--brand-glass);
  border: 1px solid var(--brand-border);
  border-radius: 50%;
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--brand-muted);
  transition: all var(--transition);
  flex-shrink: 0;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.theme-btn:hover,
.search-btn:hover {
  background-color: rgba(30, 58, 95, 0.1);
  color: var(--brand-primary);
  border-color: var(--brand-primary);
  transform: rotate(8deg) scale(1.06);
}

/* ===== 搜索栏 ===== */
.search-bar {
  display: none;
  padding: 12px 0;
  border-top: 1px solid var(--brand-glass-border);
  background: var(--brand-glass);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.search-bar.active {
  display: block;
  animation: slideDown 0.3s ease;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.search-bar form {
  display: flex;
  gap: 8px;
}

.search-bar input {
  flex: 1;
  padding: 10px 16px;
  border: 1px solid var(--brand-border);
  border-radius: 10px;
  font-size: 0.95rem;
  background-color: var(--brand-light);
  color: var(--brand-text);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.search-bar input:focus {
  border-color: var(--brand-primary);
  box-shadow: 0 0 0 3px rgba(30, 58, 95, 0.12);
}

.search-bar button {
  padding: 10px 24px;
  background: linear-gradient(135deg, var(--brand-primary), var(--brand-dark));
  color: #fff;
  border: none;
  border-radius: 10px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}

.search-bar button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(30, 58, 95, 0.3);
}

/* ===== 面包屑 ===== */
.breadcrumb {
  padding: 14px 0;
  font-size: 0.85rem;
  color: var(--brand-muted);
}

.breadcrumb a {
  color: var(--brand-muted);
  text-decoration: none;
  transition: color var(--transition);
}

.breadcrumb a:hover {
  color: var(--brand-primary);
  text-decoration: underline;
}

.breadcrumb span {
  margin: 0 6px;
}

/* ===== 首屏 Banner ===== */
.hero {
  background: linear-gradient(135deg, #0b1a2f 0%, #142c4a 45%, #1e3a5f 100%);
  color: #fff;
  padding: 64px 0 52px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  left: -120px;
  bottom: -140px;
  width: 360px;
  height: 360px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(230, 184, 0, 0.12) 0%, transparent 70%);
  pointer-events: none;
}

.hero::after {
  content: "";
  position: absolute;
  right: -80px;
  top: -80px;
  width: 320px;
  height: 320px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(230, 184, 0, 0.1) 0%, transparent 70%);
  pointer-events: none;
  animation: floatOrb 12s ease-in-out infinite;
}

@keyframes floatOrb {
  0%, 100% {
    transform: translate(0, 0) scale(1);
  }
  50% {
    transform: translate(-24px, 24px) scale(1.08);
  }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 720px;
}

.hero-badge {
  display: inline-block;
  background: rgba(230, 184, 0, 0.16);
  color: var(--brand-accent);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 5px 16px;
  border-radius: 20px;
  margin-bottom: 18px;
  letter-spacing: 0.5px;
  border: 1px solid rgba(230, 184, 0, 0.25);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.hero h1 {
  font-size: 2.2rem;
  line-height: 1.3;
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.hero h1 strong {
  color: var(--brand-accent);
  font-weight: 700;
  background: linear-gradient(120deg, #e6b800, #f5d76e);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  font-size: 1.05rem;
  color: rgba(255, 255, 255, 0.82);
  margin-bottom: 28px;
  line-height: 1.75;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px 28px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: linear-gradient(135deg, #e6b800, #f5d76e);
  color: #1a1a1a;
  box-shadow: 0 4px 16px rgba(230, 184, 0, 0.3);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 28px rgba(230, 184, 0, 0.42);
  filter: brightness(1.05);
}

.btn-outline {
  background: rgba(255, 255, 255, 0.06);
  color: #fff;
  border: 1.5px solid rgba(255, 255, 255, 0.35);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.btn-outline:hover {
  border-color: #fff;
  background: rgba(255, 255, 255, 0.14);
  transform: translateY(-3px);
}

/* ===== 数据统计 ===== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 20px;
  margin-top: 44px;
  padding-top: 32px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.stat-item {
  text-align: left;
  transition: transform var(--transition);
}

.stat-item:hover {
  transform: translateY(-4px);
}

.stat-number {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--brand-accent);
  line-height: 1.2;
  font-variant-numeric: tabular-nums;
}

.stat-label {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.65);
  margin-top: 4px;
}

/* ===== 通用区块 ===== */
.section {
  padding: 56px 0;
  position: relative;
}

.section-alt {
  background-color: var(--brand-white);
  transition: background-color 0.4s ease;
}

.section-header {
  margin-bottom: 36px;
}

.section-header h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--brand-dark);
  margin-bottom: 8px;
  position: relative;
  display: inline-block;
  letter-spacing: -0.3px;
}

.section-header h2::after {
  content: "";
  display: block;
  width: 44px;
  height: 3px;
  background: linear-gradient(90deg, var(--brand-accent), #f5d76e);
  border-radius: 2px;
  margin-top: 10px;
}

.section-header p {
  color: var(--brand-muted);
  font-size: 0.95rem;
  margin-top: 10px;
  max-width: 680px;
}

/* ===== 卡片网格 ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.card {
  background: var(--brand-glass);
  backdrop-filter: blur(14px) saturate(1.4);
  -webkit-backdrop-filter: blur(14px) saturate(1.4);
  border: 1px solid var(--brand-glass-border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  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-accent), transparent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(230, 184, 0, 0.35);
}

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

.card-icon {
  width: 46px;
  height: 46px;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(30, 58, 95, 0.12), rgba(230, 184, 0, 0.12));
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  color: var(--brand-primary);
  transition: transform var(--transition), background var(--transition);
}

.card:hover .card-icon {
  transform: scale(1.1) rotate(-4deg);
  background: linear-gradient(135deg, rgba(230, 184, 0, 0.22), rgba(30, 58, 95, 0.18));
}

.card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--brand-dark);
}

.card p {
  font-size: 0.9rem;
  color: var(--brand-muted);
  line-height: 1.7;
}

/* ===== 文章列表 ===== */
.article-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 22px;
}

.article-item {
  background: var(--brand-glass);
  backdrop-filter: blur(14px) saturate(1.4);
  -webkit-backdrop-filter: blur(14px) saturate(1.4);
  border: 1px solid var(--brand-glass-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  position: relative;
  overflow: hidden;
}

.article-item::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(230, 184, 0, 0.05), transparent 60%);
  opacity: 0;
  transition: opacity 0.4s ease;
  pointer-events: none;
}

.article-item:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(230, 184, 0, 0.3);
}

.article-item:hover::after {
  opacity: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.78rem;
  color: var(--brand-muted);
  margin-bottom: 10px;
}

.article-meta .tag {
  background: linear-gradient(135deg, rgba(30, 58, 95, 0.1), rgba(230, 184, 0, 0.1));
  color: var(--brand-primary);
  padding: 2px 12px;
  border-radius: 12px;
  font-weight: 500;
  border: 1px solid rgba(30, 58, 95, 0.08);
}

.article-item h3 {
  font-size: 1.02rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--brand-dark);
  line-height: 1.5;
  transition: color var(--transition);
}

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

.article-item p {
  font-size: 0.88rem;
  color: var(--brand-muted);
  line-height: 1.7;
  flex: 1;
  margin-bottom: 14px;
}

.article-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--brand-primary);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: color var(--transition), gap var(--transition);
}

.article-link:hover {
  color: var(--brand-accent);
  gap: 8px;
}

/* ===== FAQ ===== */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.faq-item {
  background: var(--brand-glass);
  backdrop-filter: blur(14px) saturate(1.4);
  -webkit-backdrop-filter: blur(14px) saturate(1.4);
  border: 1px solid var(--brand-glass-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: box-shadow var(--transition), border-color var(--transition), transform var(--transition);
}

.faq-item:hover {
  box-shadow: var(--shadow-md);
  border-color: rgba(230, 184, 0, 0.3);
}

.faq-item.open {
  border-color: rgba(230, 184, 0, 0.45);
  box-shadow: var(--shadow-md);
}

.faq-question {
  width: 100%;
  background: none;
  border: none;
  padding: 18px 22px;
  text-align: left;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--brand-dark);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  font-family: inherit;
  transition: background-color var(--transition), color var(--transition);
}

.faq-question:hover {
  background-color: rgba(30, 58, 95, 0.04);
}

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

.faq-question .arrow {
  flex-shrink: 0;
  transition: transform 0.35s cubic-bezier(0.34, 1.2, 0.64, 1);
  color: var(--brand-muted);
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease, opacity 0.35s ease;
  padding: 0 22px;
  color: var(--brand-muted);
  font-size: 0.9rem;
  line-height: 1.75;
  opacity: 0;
}

.faq-item.open .faq-answer {
  max-height: 500px;
  padding: 0 22px 20px;
  opacity: 1;
}

/* ===== HowTo 步骤 ===== */
.howto-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  counter-reset: step;
}

.howto-step {
  background: var(--brand-glass);
  backdrop-filter: blur(14px) saturate(1.4);
  -webkit-backdrop-filter: blur(14px) saturate(1.4);
  border: 1px solid var(--brand-glass-border);
  border-radius: var(--radius-lg);
  padding: 28px 22px;
  position: relative;
  counter-increment: step;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.howto-step:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(230, 184, 0, 0.35);
}

.howto-step::before {
  content: counter(step);
  position: absolute;
  top: -14px;
  left: 22px;
  width: 34px;
  height: 34px;
  background: linear-gradient(135deg, var(--brand-primary), var(--brand-dark));
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
  box-shadow: 0 4px 12px rgba(30, 58, 95, 0.3);
  transition: transform var(--transition), background var(--transition);
}

.howto-step:hover::before {
  transform: scale(1.15) rotate(-8deg);
  background: linear-gradient(135deg, var(--brand-accent), #f5d76e);
  color: #1a1a1a;
}

.howto-step h4 {
  font-size: 0.98rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--brand-dark);
  margin-top: 8px;
}

.howto-step p {
  font-size: 0.88rem;
  color: var(--brand-muted);
  line-height: 1.7;
}

/* ===== 团队 ===== */
.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 22px;
}

.team-card {
  background: var(--brand-glass);
  backdrop-filter: blur(14px) saturate(1.4);
  -webkit-backdrop-filter: blur(14px) saturate(1.4);
  border: 1px solid var(--brand-glass-border);
  border-radius: var(--radius-lg);
  padding: 26px 24px;
  text-align: center;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.team-card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: var(--shadow-lg);
  border-color: rgba(230, 184, 0, 0.35);
}

.team-avatar {
  width: 68px;
  height: 68px;
  border-radius: 50%;
  margin: 0 auto 14px;
  background: linear-gradient(135deg, var(--brand-primary), var(--brand-accent));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 1.35rem;
  box-shadow: 0 6px 20px rgba(30, 58, 95, 0.28);
  transition: transform var(--transition), box-shadow var(--transition);
}

.team-card:hover .team-avatar {
  transform: scale(1.08) rotate(6deg);
  box-shadow: 0 10px 28px rgba(230, 184, 0, 0.4);
}

.team-card h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--brand-dark);
}

.team-card .role {
  font-size: 0.8rem;
  color: var(--brand-accent);
  font-weight: 600;
  margin-bottom: 8px;
}

.team-card p {
  font-size: 0.82rem;
  color: var(--brand-muted);
  line-height: 1.6;
}

/* ===== 联系信息 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 22px;
}

.contact-item {
  background: var(--brand-glass);
  backdrop-filter: blur(14px) saturate(1.4);
  -webkit-backdrop-filter: blur(14px) saturate(1.4);
  border: 1px solid var(--brand-glass-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.contact-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(230, 184, 0, 0.3);
}

.contact-item h4 {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--brand-dark);
  margin-bottom: 8px;
}

.contact-item p {
  font-size: 0.88rem;
  color: var(--brand-muted);
  line-height: 1.7;
}

.contact-item a {
  color: var(--brand-primary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition);
}

.contact-item a:hover {
  color: var(--brand-accent);
  text-decoration: underline;
}

/* ===== 页脚 ===== */
.site-footer {
  background: linear-gradient(160deg, #0b1a2f 0%, #0f2238 60%, #142c4a 100%);
  color: rgba(255, 255, 255, 0.75);
  padding: 52px 0 24px;
  font-size: 0.85rem;
  position: relative;
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -60px;
  right: -60px;
  width: 240px;
  height: 240px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(230, 184, 0, 0.08), transparent 70%);
  pointer-events: none;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 32px;
  margin-bottom: 36px;
  position: relative;
  z-index: 1;
}

.footer-col h4 {
  color: #fff;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 14px;
  position: relative;
  padding-bottom: 8px;
}

.footer-col h4::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 28px;
  height: 2px;
  background: var(--brand-accent);
  border-radius: 2px;
}

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

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  color: rgba(255, 255, 255, 0.65);
  text-decoration: none;
  transition: color var(--transition), padding-left var(--transition);
  display: inline-block;
}

.footer-col a:hover {
  color: var(--brand-accent);
  padding-left: 4px;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 20px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.5);
  position: relative;
  z-index: 1;
}

.footer-bottom a {
  color: rgba(255, 255, 255, 0.6);
  text-decoration: none;
  transition: color var(--transition);
}

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

/* ===== 返回顶部 ===== */
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-primary), var(--brand-dark));
  color: #fff;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px) scale(0.9);
  transition: all 0.35s cubic-bezier(0.34, 1.2, 0.64, 1);
  z-index: 99;
}

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

.back-to-top:hover {
  background: linear-gradient(135deg, var(--brand-accent), #f5d76e);
  color: #1a1a1a;
  transform: translateY(-4px) scale(1.06);
  box-shadow: 0 12px 32px rgba(230, 184, 0, 0.4);
}

/* ===== 滚动动画 ===== */
.fade-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1), transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
  will-change: opacity, transform;
}

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

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .nav-toggle {
    display: block;
  }

  .main-nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--brand-glass);
    backdrop-filter: blur(20px) saturate(1.6);
    -webkit-backdrop-filter: blur(20px) saturate(1.6);
    border-bottom: 1px solid var(--brand-glass-border);
    box-shadow: var(--shadow-lg);
    padding: 10px 20px 18px;
    animation: slideDown 0.3s ease;
  }

  .main-nav.open {
    display: block;
  }

  .main-nav ul {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .main-nav a {
    display: block;
    padding: 12px 10px;
    border-radius: 10px;
  }

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

  .main-nav a:hover {
    background-color: rgba(30, 58, 95, 0.08);
    padding-left: 16px;
  }

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

  .hero {
    padding: 44px 0 36px;
  }

  .section {
    padding: 48px 0;
  }
}

@media (max-width: 600px) {
  .container {
    padding: 0 16px;
  }

  .hero h1 {
    font-size: 1.45rem;
  }

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

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    width: 100%;
  }

  .stats-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }

  .stat-number {
    font-size: 1.5rem;
  }

  .section {
    padding: 40px 0;
  }

  .section-header h2 {
    font-size: 1.3rem;
  }

  .card-grid,
  .article-list,
  .team-grid,
  .contact-grid,
  .howto-steps {
    grid-template-columns: 1fr;
  }

  .back-to-top {
    bottom: 18px;
    right: 18px;
    width: 42px;
    height: 42px;
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }

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

@media (max-width: 380px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .stats-row {
    grid-template-columns: 1fr;
  }
}

/* ===== 无障碍与动效偏好 ===== */
@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-up {
    opacity: 1;
    transform: none;
  }
}

::selection {
  background: rgba(230, 184, 0, 0.3);
  color: var(--brand-dark);
}

:focus-visible {
  outline: 2px solid var(--brand-accent);
  outline-offset: 2px;
  border-radius: 4px;
}