:root {
  --bg: #f0f4fa;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-solid: #ffffff;
  --text-primary: #0f1a2e;
  --text-secondary: #2a3a52;
  --text-muted: #4a5a72;
  --brand: #1a2a4a;
  --brand-light: #2c3e5c;
  --accent: #e85d04;
  --accent-hover: #c44d00;
  --accent-glow: rgba(232, 93, 4, 0.35);
  --border: rgba(26, 42, 74, 0.12);
  --border-strong: rgba(26, 42, 74, 0.22);
  --shadow: rgba(15, 26, 46, 0.08);
  --shadow-lg: rgba(15, 26, 46, 0.14);
  --nav-bg: rgba(255, 255, 255, 0.82);
  --nav-text: #0f1a2e;
  --footer-bg: #0f1a2e;
  --footer-text: #dce4f0;
  --card-bg: rgba(255, 255, 255, 0.68);
  --card-text: #1f2937;
  --faq-bg: rgba(255, 255, 255, 0.7);
  --faq-text: #1f2937;
  --faq-question: #0f1a2e;
  --faq-answer: #2a3a52;
  --btn-text: #ffffff;
  --link: #1a5a9a;
  --link-hover: #0d3b6b;
  --input-bg: rgba(255, 255, 255, 0.65);
  --input-text: #0f1a2e;
  --input-border: rgba(26, 42, 74, 0.2);
  --placeholder: #6a7a8a;
  --table-header: #1a2a4a;
  --table-header-text: #ffffff;
  --table-row-alt: rgba(240, 244, 250, 0.6);
  --table-text: #1f2937;
  --tag-bg: rgba(232, 237, 245, 0.8);
  --tag-text: #1a2a4a;
  --glass-blur: 16px;
  --glass-border: rgba(255, 255, 255, 0.35);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
}

html[data-theme="dark"] {
  --bg: #0a0f1a;
  --surface: rgba(30, 41, 59, 0.68);
  --surface-solid: #1e293b;
  --text-primary: #f1f5f9;
  --text-secondary: #e2e8f0;
  --text-muted: #cbd5e1;
  --brand: #4a7ab5;
  --brand-light: #5b8bc5;
  --accent: #f97316;
  --accent-hover: #ea580c;
  --accent-glow: rgba(249, 115, 22, 0.35);
  --border: rgba(148, 163, 184, 0.16);
  --border-strong: rgba(148, 163, 184, 0.28);
  --shadow: rgba(0, 0, 0, 0.35);
  --shadow-lg: rgba(0, 0, 0, 0.5);
  --nav-bg: rgba(30, 41, 59, 0.82);
  --nav-text: #f1f5f9;
  --footer-bg: #070b14;
  --footer-text: #e2e8f0;
  --card-bg: rgba(30, 41, 59, 0.62);
  --card-text: #e2e8f0;
  --faq-bg: rgba(30, 41, 59, 0.65);
  --faq-text: #e2e8f0;
  --faq-question: #f8fafc;
  --faq-answer: #cbd5e1;
  --btn-text: #ffffff;
  --link: #7ba9d4;
  --link-hover: #a0c4e8;
  --input-bg: rgba(30, 41, 59, 0.6);
  --input-text: #f1f5f9;
  --input-border: rgba(148, 163, 184, 0.25);
  --placeholder: #94a3b8;
  --table-header: #2c3e5c;
  --table-header-text: #f1f5f9;
  --table-row-alt: rgba(30, 41, 59, 0.5);
  --table-text: #e2e8f0;
  --tag-bg: rgba(44, 62, 92, 0.7);
  --tag-text: #e2e8f0;
  --glass-border: rgba(148, 163, 184, 0.18);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background-color: var(--bg);
  background-image:
    radial-gradient(ellipse 80% 50% at 10% 0%, rgba(26, 42, 74, 0.06), transparent),
    radial-gradient(ellipse 60% 40% at 90% 10%, rgba(232, 93, 4, 0.05), transparent),
    radial-gradient(ellipse 70% 50% at 50% 100%, rgba(44, 62, 92, 0.05), transparent);
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.7;
  transition: background-color 0.4s ease, color 0.4s ease;
  overflow-x: hidden;
}

html[data-theme="dark"] body {
  background-image:
    radial-gradient(ellipse 80% 50% at 10% 0%, rgba(74, 122, 181, 0.08), transparent),
    radial-gradient(ellipse 60% 40% at 90% 10%, rgba(249, 115, 22, 0.06), transparent),
    radial-gradient(ellipse 70% 50% at 50% 100%, rgba(44, 62, 92, 0.12), transparent);
}

a {
  color: var(--link);
  text-decoration: none;
  transition: color 0.25s ease;
}

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

img {
  max-width: 100%;
  height: auto;
}

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

/* ============ 导航 ============ */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--nav-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(1.6);
  backdrop-filter: blur(var(--glass-blur)) saturate(1.6);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 2px 20px var(--shadow);
  transition: background 0.4s ease, border-color 0.4s ease, box-shadow 0.3s ease;
}

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

.nav-brand {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--brand);
  letter-spacing: -0.5px;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav-brand span {
  background: linear-gradient(135deg, var(--accent), #ff8c42);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.nav-brand:hover {
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 26px;
  list-style: none;
  align-items: center;
}

.nav-links a {
  color: var(--nav-text);
  font-weight: 600;
  font-size: 0.94rem;
  text-decoration: none;
  position: relative;
  padding: 4px 0;
  transition: color 0.25s ease;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), #ff8c42);
  border-radius: 2px;
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-links a:hover {
  color: var(--accent);
  text-decoration: none;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.theme-toggle {
  background: var(--surface);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text-primary);
  transition: background 0.25s, border-color 0.25s, color 0.25s, transform 0.2s;
}

.theme-toggle:hover {
  background: var(--tag-bg);
  border-color: var(--border-strong);
  transform: scale(1.05);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.6rem;
  cursor: pointer;
  color: var(--text-primary);
  padding: 4px 8px;
  transition: transform 0.2s;
}

.mobile-menu-btn:hover {
  transform: scale(1.1);
}

/* ============ 搜索框 ============ */
.search-box {
  display: flex;
  align-items: center;
  background: var(--input-bg);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border: 1px solid var(--input-border);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  gap: 6px;
  transition: border-color 0.25s, box-shadow 0.25s;
}

.search-box:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.search-box input {
  border: none;
  outline: none;
  background: transparent;
  color: var(--input-text);
  font-size: 0.9rem;
  width: 140px;
}

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

.search-box button {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 1rem;
  padding: 2px;
  transition: color 0.2s, transform 0.2s;
}

.search-box button:hover {
  color: var(--accent);
  transform: scale(1.15);
}

/* ============ Banner ============ */
.banner {
  position: relative;
  background: linear-gradient(135deg, #0f1a2e 0%, #1a2a4a 35%, #2c3e5c 65%, #1a3a5a 100%);
  color: #ffffff;
  padding: 80px 0 72px;
  overflow: hidden;
  isolation: isolate;
}

.banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle 500px at 15% 30%, rgba(232, 93, 4, 0.18), transparent),
    radial-gradient(circle 400px at 85% 70%, rgba(74, 122, 181, 0.2), transparent),
    radial-gradient(circle 300px at 50% 110%, rgba(232, 93, 4, 0.1), transparent);
  pointer-events: none;
  z-index: 0;
}

.banner::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 60%, rgba(0, 0, 0, 0.25) 100%);
  pointer-events: none;
  z-index: 0;
}

.banner .container {
  position: relative;
  z-index: 1;
}

.banner h1 {
  font-size: 2.7rem;
  font-weight: 800;
  line-height: 1.28;
  margin-bottom: 20px;
  color: #ffffff;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.45);
  letter-spacing: -0.5px;
  animation: bannerFadeUp 0.8s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.banner p {
  font-size: 1.12rem;
  max-width: 720px;
  color: #e2e8f0;
  margin-bottom: 34px;
  text-shadow: 0 1px 8px rgba(0, 0, 0, 0.35);
  animation: bannerFadeUp 0.8s cubic-bezier(0.16, 1, 0.3, 1) 0.15s both;
}

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

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

/* ============ 按钮 ============ */
.btn {
  display: inline-block;
  padding: 14px 34px;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  text-decoration: none;
  position: relative;
  overflow: hidden;
  transition: background 0.25s, transform 0.2s, box-shadow 0.3s;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s ease;
}

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

.btn-primary {
  background: linear-gradient(135deg, var(--accent), #ff7a2e);
  color: #ffffff;
  box-shadow: 0 4px 20px var(--accent-glow);
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--accent-hover), #e85d04);
  color: #ffffff;
  text-decoration: none;
  transform: translateY(-3px);
  box-shadow: 0 8px 30px var(--accent-glow);
}

.btn-outline {
  background: rgba(255, 255, 255, 0.06);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border: 2px solid rgba(255, 255, 255, 0.7);
  color: #ffffff;
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.16);
  border-color: #ffffff;
  color: #ffffff;
  text-decoration: none;
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.25);
}

/* ============ 通用区块 ============ */
.section {
  padding: 72px 0;
  position: relative;
}

.section-alt {
  background: var(--surface);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  transition: background 0.4s ease, border-color 0.4s ease;
}

.section-title {
  font-size: 1.95rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 12px;
  letter-spacing: -0.4px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 56px;
  height: 4px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), #ff8c42);
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin-bottom: 44px;
  max-width: 720px;
  margin-top: 16px;
}

.section-header {
  text-align: center;
  margin-bottom: 52px;
}

.section-header .section-title::after {
  left: 50%;
  transform: translateX(-50%);
}

.section-header .section-subtitle {
  margin-left: auto;
  margin-right: auto;
}

/* ============ 卡片网格 ============ */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
}

.card {
  background: var(--card-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(1.4);
  backdrop-filter: blur(var(--glass-blur)) saturate(1.4);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 30px 26px;
  box-shadow: 0 4px 20px var(--shadow);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.3s ease, background 0.4s ease, border-color 0.3s ease;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), #ff8c42, var(--brand-light));
  opacity: 0;
  transition: opacity 0.3s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 40px var(--shadow-lg);
  border-color: var(--border-strong);
}

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

.card h3 {
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
  letter-spacing: -0.2px;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.75;
}

.card-icon {
  font-size: 2.1rem;
  margin-bottom: 16px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(232, 93, 4, 0.1), rgba(44, 62, 92, 0.1));
  transition: transform 0.3s ease, background 0.3s ease;
}

.card:hover .card-icon {
  transform: scale(1.1) rotate(-4deg);
  background: linear-gradient(135deg, rgba(232, 93, 4, 0.18), rgba(44, 62, 92, 0.16));
}

/* ============ 文章列表 ============ */
.article-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.article-card {
  background: var(--card-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 26px;
  box-shadow: 0 3px 16px var(--shadow);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.3s, background 0.4s, border-color 0.3s;
  position: relative;
}

.article-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 32px var(--shadow-lg);
  border-color: var(--border-strong);
}

.article-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.45;
  transition: color 0.25s;
}

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

.article-meta {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.article-card p {
  color: var(--text-secondary);
  font-size: 0.93rem;
  margin-bottom: 16px;
  line-height: 1.7;
}

.read-more {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--link);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: color 0.25s, gap 0.25s;
}

.read-more:hover {
  color: var(--link-hover);
  text-decoration: underline;
  gap: 8px;
}

/* ============ FAQ ============ */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
}

.faq-item {
  background: var(--faq-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: background 0.4s, border-color 0.3s, box-shadow 0.3s;
}

.faq-item:hover {
  border-color: var(--border-strong);
  box-shadow: 0 4px 16px var(--shadow);
}

.faq-item.open {
  border-color: var(--accent);
  box-shadow: 0 4px 20px var(--accent-glow);
}

.faq-question {
  width: 100%;
  text-align: left;
  padding: 18px 24px;
  font-size: 1rem;
  font-weight: 700;
  color: var(--faq-question);
  background: none;
  border: none;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  transition: background 0.25s, color 0.25s;
  font-family: inherit;
}

.faq-question:hover {
  background: var(--tag-bg);
  color: var(--text-primary);
}

.faq-question .arrow {
  font-size: 1rem;
  transition: transform 0.35s cubic-bezier(0.16, 1, 0.3, 1);
  color: var(--accent);
  flex-shrink: 0;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s cubic-bezier(0.16, 1, 0.3, 1), padding 0.35s ease;
  padding: 0 24px;
  color: var(--faq-answer);
  font-size: 0.95rem;
  line-height: 1.85;
}

.faq-item.open .faq-answer {
  max-height: 600px;
  padding: 0 24px 22px;
}

/* ============ HowTo ============ */
.howto-steps {
  counter-reset: step;
  max-width: 800px;
  margin: 0 auto;
}

.howto-step {
  position: relative;
  padding: 0 0 36px 64px;
  counter-increment: step;
}

.howto-step::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.05rem;
  box-shadow: 0 4px 14px rgba(26, 42, 74, 0.3);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.howto-step:hover::before {
  transform: scale(1.12);
  box-shadow: 0 6px 20px var(--accent-glow);
}

.howto-step::after {
  content: '';
  position: absolute;
  left: 21px;
  top: 48px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--border-strong), transparent);
}

.howto-step:last-child::after {
  display: none;
}

.howto-step h4 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.howto-step p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.75;
}

/* ============ 表格 ============ */
.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  box-shadow: 0 4px 20px var(--shadow);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.93rem;
}

thead {
  background: linear-gradient(135deg, var(--table-header), var(--brand-light));
  color: var(--table-header-text);
}

th {
  padding: 15px 20px;
  text-align: left;
  font-weight: 700;
  color: var(--table-header-text);
  white-space: nowrap;
}

td {
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  color: var(--table-text);
  transition: background 0.2s;
}

tbody tr {
  transition: background 0.2s;
}

tbody tr:nth-child(even) {
  background: var(--table-row-alt);
}

tbody tr:hover {
  background: var(--tag-bg);
}

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

/* ============ 标签 ============ */
.tag {
  display: inline-block;
  background: var(--tag-bg);
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
  color: var(--tag-text);
  border-radius: var(--radius-sm);
  padding: 5px 14px;
  font-size: 0.82rem;
  font-weight: 600;
  margin: 3px 4px 3px 0;
  border: 1px solid var(--border);
  transition: background 0.25s, transform 0.2s, border-color 0.25s;
}

.tag:hover {
  background: var(--brand);
  color: #ffffff;
  transform: translateY(-2px);
  border-color: var(--brand);
}

/* ============ 联系信息 ============ */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.contact-item {
  background: var(--card-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.3s, border-color 0.3s;
}

.contact-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 28px var(--shadow-lg);
  border-color: var(--border-strong);
}

.contact-item h4 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.contact-item p {
  color: var(--text-secondary);
  font-size: 0.93rem;
  line-height: 1.7;
}

/* ============ Footer ============ */
footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  padding: 60px 0 30px;
  transition: background 0.4s, color 0.4s;
  position: relative;
  overflow: hidden;
}

footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0.5;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 36px;
  margin-bottom: 44px;
}

.footer-col h4 {
  font-size: 1rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 18px;
  position: relative;
  display: inline-block;
}

.footer-col h4::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 28px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
}

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

.footer-col li {
  margin-bottom: 10px;
}

.footer-col a {
  color: var(--footer-text);
  font-size: 0.9rem;
  text-decoration: none;
  transition: color 0.25s, padding-left 0.25s;
  display: inline-block;
}

.footer-col a:hover {
  color: #ffffff;
  text-decoration: none;
  padding-left: 4px;
}

.footer-col p {
  color: var(--footer-text);
  font-size: 0.9rem;
  line-height: 1.8;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding-top: 26px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.85rem;
  color: var(--footer-text);
}

.footer-bottom a {
  color: var(--footer-text);
  transition: color 0.25s;
}

.footer-bottom a:hover {
  color: #ffffff;
}

/* ============ 返回顶部 ============ */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #ff7a2e);
  color: #ffffff;
  border: none;
  font-size: 1.3rem;
  cursor: pointer;
  box-shadow: 0 6px 22px var(--accent-glow);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.35s, visibility 0.35s, transform 0.25s, box-shadow 0.25s;
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.back-to-top:hover {
  transform: translateY(-4px) scale(1.08);
  box-shadow: 0 10px 32px var(--accent-glow);
}

/* ============ 滚动动画 ============ */
.fade-in {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1), transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

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

/* ============ 面包屑 ============ */
.breadcrumb {
  padding: 18px 0;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--link);
  transition: color 0.25s;
}

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

.breadcrumb span {
  margin: 0 8px;
  color: var(--text-muted);
}

/* ============ 数字统计 ============ */
.stat-number {
  font-size: 2.3rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), #ff8c42);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  display: block;
  line-height: 1.2;
}

.stat-label {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 600;
}

/* ============ 内部锚点导航 ============ */
.anchor-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 36px;
}

.anchor-nav a {
  background: var(--tag-bg);
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
  color: var(--tag-text);
  padding: 9px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid var(--border);
  transition: background 0.25s, color 0.25s, transform 0.2s, box-shadow 0.25s, border-color 0.25s;
}

.anchor-nav a:hover {
  background: linear-gradient(135deg, var(--brand), var(--brand-light));
  color: #ffffff;
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(26, 42, 74, 0.3);
  border-color: var(--brand);
}

/* ============ 时间线 ============ */
.timeline {
  position: relative;
  padding-left: 34px;
  border-left: 3px solid var(--brand);
}

.timeline-item {
  margin-bottom: 30px;
  position: relative;
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -42px;
  top: 7px;
  width: 14px;
  height: 14px;
  background: linear-gradient(135deg, var(--accent), #ff8c42);
  border-radius: 50%;
  border: 3px solid var(--surface-solid);
  box-shadow: 0 0 0 3px var(--accent-glow);
  transition: transform 0.25s;
}

.timeline-item:hover::before {
  transform: scale(1.25);
}

.timeline-item h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.timeline-item p {
  color: var(--text-secondary);
  font-size: 0.93rem;
  line-height: 1.7;
}

/* ============ 辅助类 ============ */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* ============ 响应式 ============ */
@media (max-width: 992px) {
  .grid-3,
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .banner h1 {
    font-size: 2.1rem;
  }

  .banner {
    padding: 64px 0 56px;
  }

  .section {
    padding: 56px 0;
  }

  .section-title {
    font-size: 1.7rem;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--nav-bg);
    -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(1.6);
    backdrop-filter: blur(var(--glass-blur)) saturate(1.6);
    flex-direction: column;
    padding: 22px 20px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 12px 30px var(--shadow-lg);
    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);
    }
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    font-size: 1rem;
    padding: 8px 0;
    width: 100%;
  }

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

  .search-box {
    display: none;
  }

  .grid-3,
  .grid-4,
  .grid-2,
  .article-list,
  .contact-grid {
    grid-template-columns: 1fr;
  }

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

  .banner h1 {
    font-size: 1.65rem;
  }

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

  .banner {
    padding: 52px 0 46px;
  }

  .section {
    padding: 48px 0;
  }

  .section-title {
    font-size: 1.45rem;
  }

  .section-subtitle {
    font-size: 0.98rem;
    margin-bottom: 32px;
  }

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

  .btn {
    padding: 13px 26px;
    font-size: 0.95rem;
  }

  .card {
    padding: 24px 20px;
  }

  .howto-step {
    padding-left: 56px;
  }

  .howto-step::before {
    width: 40px;
    height: 40px;
    font-size: 0.95rem;
  }

  .howto-step::after {
    left: 19px;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
    font-size: 1.15rem;
  }

  .timeline {
    padding-left: 28px;
  }

  .timeline-item::before {
    left: -36px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .banner h1 {
    font-size: 1.4rem;
  }

  .section-title {
    font-size: 1.3rem;
  }

  .card h3 {
    font-size: 1.08rem;
  }

  .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;
  }
}

/* ============ 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-in {
    opacity: 1;
    transform: none;
  }
}

/* ============ 选择文本样式 ============ */
::selection {
  background: var(--accent);
  color: #ffffff;
}

::-moz-selection {
  background: var(--accent);
  color: #ffffff;
}

/* ============ 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-light), var(--brand));
  border-radius: 5px;
  border: 2px solid var(--bg);
}

::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(180deg, var(--accent), var(--accent-hover));
}

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