/* =========================================================
   漫小社漫画 - 完整样式表 (style.css)
   风格：现代清新 · 渐变Banner · 圆角卡片 · 毛玻璃 · 暗色模式
   ========================================================= */

/* ---------- 重置与基础变量 ---------- */
:root {
  --primary: #2b5a8c;
  --primary-light: #4b7ab5;
  --primary-dark: #1a3a5c;
  --accent: #e8a838;
  --bg: #f7f9fc;
  --bg-dark: #121a24;
  --card-bg: #ffffff;
  --card-bg-dark: #1a2634;
  --text: #1e2b3c;
  --text-light: #3d5167;
  --text-muted: #7f8c9b;
  --border: #e9eef3;
  --border-dark: #2a3a4a;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.03);
  --shadow-md: 0 6px 18px rgba(0,0,0,0.05);
  --shadow-lg: 0 12px 32px rgba(0,0,0,0.08);
  --radius-sm: 12px;
  --radius-md: 20px;
  --radius-lg: 32px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --font: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'Noto Sans', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

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

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

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
  transition: background 0.4s ease, color 0.4s ease;
}

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

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 吸顶导航 ---------- */
.sticky-nav {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  z-index: 1000;
  border-bottom: 1px solid var(--border);
  transition: background 0.4s ease, border-color 0.4s ease;
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 20px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  flex-shrink: 0;
}

.logo svg {
  width: 42px;
  height: 42px;
  transition: transform var(--transition);
}

.logo:hover svg {
  transform: scale(1.06) rotate(-3deg);
}

.logo span {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--primary-dark);
  letter-spacing: 0.5px;
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  gap: 32px;
  align-items: center;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-light);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
  padding: 6px 2px;
  transition: color var(--transition);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  border-radius: 2px;
  transition: width var(--transition);
}

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

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

.search-box {
  display: flex;
  align-items: center;
  background: #f1f4f8;
  border-radius: 40px;
  padding: 8px 18px;
  gap: 8px;
  border: 1px solid transparent;
  transition: all var(--transition);
  flex-shrink: 0;
}

.search-box:focus-within {
  border-color: var(--primary-light);
  box-shadow: 0 0 0 3px rgba(43, 90, 140, 0.12);
  background: #fff;
}

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

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

.search-box svg {
  width: 18px;
  height: 18px;
  fill: var(--text-muted);
  flex-shrink: 0;
}

.menu-btn {
  display: none;
  font-size: 2rem;
  color: var(--primary-dark);
  width: 44px;
  height: 44px;
  border-radius: 12px;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
}

.menu-btn:hover {
  background: rgba(43, 90, 140, 0.08);
}

.mobile-menu {
  display: none;
  flex-direction: column;
  background: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(20px);
  padding: 8px 24px 20px;
  gap: 4px;
  border-bottom: 1px solid var(--border);
  box-shadow: 0 16px 32px rgba(0,0,0,0.06);
}

.mobile-menu.open {
  display: flex;
  animation: slideDown 0.3s ease;
}

.mobile-menu a {
  padding: 12px 8px;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-light);
  border-radius: 10px;
  transition: all var(--transition);
}

.mobile-menu a:hover {
  background: rgba(43, 90, 140, 0.08);
  color: var(--primary);
  padding-left: 16px;
}

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

/* ---------- 首屏 Hero ---------- */
.hero {
  background: linear-gradient(135deg, #e8f1fa 0%, #f5f9ff 45%, #ffffff 100%);
  padding: 64px 0 48px;
  border-radius: 0 0 48px 48px;
  position: relative;
  overflow: hidden;
  transition: background 0.4s ease;
}

.hero::before {
  content: '';
  position: absolute;
  top: -120px;
  right: -80px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(43, 90, 140, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-grid {
  display: flex;
  align-items: center;
  gap: 48px;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.hero-text {
  flex: 1;
  min-width: 300px;
}

.hero-text h1 {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  font-weight: 800;
  color: var(--primary-dark);
  line-height: 1.15;
  margin-bottom: 24px;
  letter-spacing: -0.5px;
}

.hero-text h1 span {
  color: var(--primary);
  position: relative;
  display: inline-block;
}

.hero-text h1 span::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 0;
  width: 100%;
  height: 8px;
  background: rgba(43, 90, 140, 0.15);
  border-radius: 4px;
  z-index: -1;
}

.hero-text p {
  font-size: 1.1rem;
  color: var(--text-light);
  max-width: 600px;
  margin-bottom: 36px;
  line-height: 1.8;
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: white;
  padding: 14px 32px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  box-shadow: 0 4px 16px rgba(43, 90, 140, 0.3);
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(43, 90, 140, 0.4);
}

.btn-outline {
  border: 2px solid var(--primary);
  color: var(--primary);
  padding: 12px 30px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
}

.btn-outline:hover {
  background: rgba(43, 90, 140, 0.08);
  transform: translateY(-2px);
}

.hero-visual {
  flex: 1;
  text-align: center;
  min-width: 280px;
}

.hero-visual svg {
  max-width: 420px;
  width: 100%;
  height: auto;
  filter: drop-shadow(0 16px 32px rgba(43, 90, 140, 0.12));
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

/* ---------- 快速统计 ---------- */
.quick-stats {
  display: flex;
  gap: 40px;
  justify-content: center;
  margin: 48px 0 8px;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.stat-item {
  text-align: center;
  padding: 16px 28px;
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(12px);
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.6);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition);
  min-width: 120px;
}

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

.stat-item .num {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1.2;
}

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

/* ---------- 通用区块 ---------- */
.section {
  padding: 56px 0;
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 800;
  color: var(--primary-dark);
  margin-bottom: 20px;
  border-left: 6px solid var(--primary);
  padding-left: 20px;
  line-height: 1.3;
  transition: color 0.4s ease;
}

.section-subtitle {
  color: var(--text-light);
  max-width: 900px;
  margin-bottom: 16px;
  font-size: 1rem;
}

/* ---------- 文章卡片网格 ---------- */
.grid-articles {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 28px;
  margin-top: 32px;
}

.article-card {
  background: var(--card-bg);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
  border: 1px solid rgba(0,0,0,0.02);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.article-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light), var(--accent));
  opacity: 0;
  transition: opacity var(--transition);
}

.article-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(43, 90, 140, 0.08);
}

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

.article-card .meta {
  color: var(--text-muted);
  font-size: 0.8rem;
  margin-bottom: 12px;
  font-weight: 500;
  letter-spacing: 0.3px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.article-card .meta::before {
  content: '📖';
  font-size: 0.9rem;
}

.article-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
  line-height: 1.5;
  transition: color var(--transition);
}

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

.article-card p {
  color: var(--text-light);
  font-size: 0.92rem;
  line-height: 1.7;
  flex: 1;
  margin-bottom: 16px;
}

.read-more {
  color: var(--primary);
  font-weight: 600;
  text-decoration: none;
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: gap var(--transition);
}

.read-more::after {
  content: '→';
  transition: transform var(--transition);
}

.read-more:hover {
  gap: 10px;
}

.read-more:hover::after {
  transform: translateX(3px);
}

/* ---------- FAQ 样式 ---------- */
.faq-item {
  background: var(--card-bg);
  border-radius: var(--radius-md);
  margin-bottom: 14px;
  padding: 20px 28px;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(0,0,0,0.02);
  transition: all var(--transition);
}

.faq-item:hover {
  box-shadow: var(--shadow-md);
  border-color: rgba(43, 90, 140, 0.1);
}

.faq-question {
  font-weight: 600;
  font-size: 1.05rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  color: var(--text);
}

.faq-icon {
  font-size: 1.4rem;
  color: var(--primary);
  transition: transform 0.3s ease;
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(43, 90, 140, 0.08);
  border-radius: 50%;
  line-height: 1;
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, margin 0.4s ease, opacity 0.3s ease;
  color: var(--text-light);
  opacity: 0;
  line-height: 1.8;
}

.faq-item.active {
  border-color: rgba(43, 90, 140, 0.2);
  box-shadow: var(--shadow-md);
}

.faq-item.active .faq-answer {
  max-height: 500px;
  margin-top: 14px;
  opacity: 1;
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
  background: var(--primary);
  color: white;
}

/* ---------- HowTo 教程 ---------- */
.howto-steps {
  background: linear-gradient(145deg, #f0f5fb, #ffffff);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(43, 90, 140, 0.06);
  transition: background 0.4s ease;
}

.step {
  display: flex;
  gap: 20px;
  margin-bottom: 24px;
  align-items: flex-start;
}

.step:last-child {
  margin-bottom: 0;
}

.step-num {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: white;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.1rem;
  flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(43, 90, 140, 0.25);
}

.step strong {
  display: block;
  margin-bottom: 4px;
  color: var(--text);
  font-size: 1.05rem;
}

.step div:last-child {
  color: var(--text-light);
  font-size: 0.95rem;
}

/* ---------- 联系 / 企业信息 ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(0,0,0,0.02);
  transition: background 0.4s ease;
}

.contact-grid h3 {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid rgba(43, 90, 140, 0.1);
}

.contact-grid p {
  margin-bottom: 10px;
  color: var(--text-light);
  font-size: 0.95rem;
  line-height: 1.8;
}

.contact-grid p strong {
  color: var(--text);
  font-weight: 600;
}

/* ---------- 底部 ---------- */
footer {
  background: linear-gradient(180deg, #0a1e33, #0d2438);
  color: #cbd5e0;
  padding: 56px 0 28px;
  margin-top: 48px;
  position: relative;
}

footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent), var(--primary-light));
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 40px;
}

.footer-grid h4 {
  color: white;
  margin-bottom: 20px;
  font-size: 1.05rem;
  font-weight: 700;
  position: relative;
  padding-bottom: 10px;
}

.footer-grid h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 32px;
  height: 3px;
  background: var(--primary-light);
  border-radius: 2px;
}

.footer-grid a {
  display: block;
  color: #a0b3c9;
  text-decoration: none;
  margin-bottom: 10px;
  font-size: 0.9rem;
  transition: all var(--transition);
}

.footer-grid a:hover {
  color: white;
  padding-left: 6px;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  margin-top: 40px;
  padding-top: 24px;
  font-size: 0.85rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  color: #7f93a8;
}

.footer-bottom a {
  color: #a0b3c9;
  transition: color var(--transition);
}

.footer-bottom a:hover {
  color: white;
}

/* ---------- 返回顶部 ---------- */
#backTop {
  position: fixed;
  bottom: 40px;
  right: 30px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: white;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  border: none;
  font-size: 1.6rem;
  box-shadow: 0 4px 16px rgba(43, 90, 140, 0.35);
  z-index: 999;
  transition: all var(--transition);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
}

#backTop.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

#backTop:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(43, 90, 140, 0.45);
}

/* ---------- 暗色模式 ---------- */
.dark-mode {
  background: var(--bg-dark);
  color: #e0e6ed;
}

.dark-mode .sticky-nav {
  background: rgba(15, 23, 34, 0.85);
  border-bottom-color: var(--border-dark);
}

.dark-mode .logo span {
  background: linear-gradient(135deg, #fff, #b0c4d9);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.dark-mode .nav-links a {
  color: #a0b3c9;
}

.dark-mode .nav-links a:hover {
  color: #7fb0e0;
}

.dark-mode .nav-links a::after {
  background: #7fb0e0;
}

.dark-mode .search-box {
  background: rgba(255, 255, 255, 0.06);
}

.dark-mode .search-box input {
  color: #e0e6ed;
}

.dark-mode .search-box input::placeholder {
  color: #6b7f96;
}

.dark-mode .menu-btn {
  color: #e0e6ed;
}

.dark-mode .mobile-menu {
  background: rgba(15, 23, 34, 0.98);
  border-bottom-color: var(--border-dark);
}

.dark-mode .mobile-menu a {
  color: #a0b3c9;
}

.dark-mode .mobile-menu a:hover {
  background: rgba(127, 176, 224, 0.1);
  color: #7fb0e0;
}

.dark-mode .hero {
  background: linear-gradient(135deg, #0f1a26, #162330);
}

.dark-mode .hero-text h1 {
  color: #fff;
}

.dark-mode .hero-text h1 span {
  color: #7fb0e0;
}

.dark-mode .hero-text h1 span::after {
  background: rgba(127, 176, 224, 0.2);
}

.dark-mode .hero-text p {
  color: #b0c4d9;
}

.dark-mode .btn-outline {
  border-color: #7fb0e0;
  color: #7fb0e0;
}

.dark-mode .btn-outline:hover {
  background: rgba(127, 176, 224, 0.1);
}

.dark-mode .stat-item {
  background: rgba(255, 255, 255, 0.04);
  border-color: rgba(255, 255, 255, 0.06);
}

.dark-mode .stat-item .num {
  color: #7fb0e0;
}

.dark-mode .stat-item .label {
  color: #7f93a8;
}

.dark-mode .section-title {
  color: #fff;
}

.dark-mode .article-card,
.dark-mode .faq-item,
.dark-mode .contact-grid {
  background: var(--card-bg-dark);
  border-color: rgba(255, 255, 255, 0.04);
}

.dark-mode .article-card h3 {
  color: #e0e6ed;
}

.dark-mode .article-card:hover h3 {
  color: #7fb0e0;
}

.dark-mode .article-card p,
.dark-mode .faq-answer,
.dark-mode .step div:last-child,
.dark-mode .contact-grid p {
  color: #a0b3c9;
}

.dark-mode .article-card .meta {
  color: #6b7f96;
}

.dark-mode .faq-question {
  color: #e0e6ed;
}

.dark-mode .faq-icon {
  background: rgba(127, 176, 224, 0.15);
  color: #7fb0e0;
}

.dark-mode .faq-item.active .faq-icon {
  background: #7fb0e0;
  color: #0f1a26;
}

.dark-mode .howto-steps {
  background: linear-gradient(145deg, #1a2634, #162230);
  border-color: rgba(255, 255, 255, 0.04);
}

.dark-mode .step strong {
  color: #e0e6ed;
}

.dark-mode .contact-grid h3 {
  color: #fff;
  border-bottom-color: rgba(255, 255, 255, 0.1);
}

.dark-mode .contact-grid p strong {
  color: #e0e6ed;
}

/* ---------- 滚动动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .hero-grid {
    gap: 32px;
  }
  
  .hero-text h1 {
    font-size: 2.4rem;
  }
  
  .contact-grid {
    grid-template-columns: 1fr;
    padding: 32px;
  }
}

@media (max-width: 900px) {
  .nav-links {
    display: none;
  }
  
  .menu-btn {
    display: flex;
  }
  
  .search-box {
    display: none;
  }
  
  .hero {
    padding: 48px 0 40px;
    border-radius: 0 0 32px 32px;
  }
  
  .hero-text h1 {
    font-size: 2rem;
  }
  
  .hero-text p {
    font-size: 1rem;
  }
  
  .quick-stats {
    gap: 16px;
    margin-top: 32px;
  }
  
  .stat-item {
    padding: 12px 20px;
    min-width: 100px;
  }
  
  .stat-item .num {
    font-size: 1.6rem;
  }
  
  .section {
    padding: 40px 0;
  }
  
  .grid-articles {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 20px;
  }
  
  .howto-steps {
    padding: 24px;
  }
}

@media (max-width: 640px) {
  .container {
    padding: 0 16px;
  }
  
  .nav-wrap {
    height: 64px;
  }
  
  .logo span {
    font-size: 1.2rem;
  }
  
  .logo svg {
    width: 36px;
    height: 36px;
  }
  
  .hero-text h1 {
    font-size: 1.7rem;
  }
  
  .hero-text p {
    font-size: 0.95rem;
    margin-bottom: 24px;
  }
  
  .hero-cta {
    flex-direction: column;
    gap: 12px;
  }
  
  .btn-primary, .btn-outline {
    width: 100%;
    text-align: center;
    justify-content: center;
  }
  
  .hero-visual svg {
    max-width: 280px;
  }
  
  .quick-stats {
    gap: 12px;
  }
  
  .stat-item {
    padding: 10px 14px;
    min-width: 85px;
  }
  
  .stat-item .num {
    font-size: 1.3rem;
  }
  
  .stat-item .label {
    font-size: 0.8rem;
  }
  
  .section-title {
    font-size: 1.4rem;
    padding-left: 14px;
  }
  
  .grid-articles {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  
  .article-card {
    padding: 20px;
  }
  
  .faq-item {
    padding: 16px 20px;
  }
  
  .faq-question {
    font-size: 0.95rem;
  }
  
  .howto-steps {
    padding: 20px;
  }
  
  .step {
    gap: 14px;
  }
  
  .step-num {
    width: 34px;
    height: 34px;
    font-size: 1rem;
  }
  
  .contact-grid {
    padding: 24px;
    gap: 24px;
  }
  
  .footer-grid {
    gap: 28px;
  }
  
  .footer-bottom {
    flex-direction: column;
    text-align: center;
    justify-content: center;
  }
  
  #backTop {
    bottom: 24px;
    right: 20px;
    width: 44px;
    height: 44px;
    font-size: 1.3rem;
  }
}

/* ---------- 暗色模式切换按钮 ---------- */
.dark-toggle-btn {
  position: fixed;
  bottom: 100px;
  right: 30px;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  border: none;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: white;
  font-size: 1.3rem;
  cursor: pointer;
  z-index: 999;
  box-shadow: 0 4px 16px rgba(43, 90, 140, 0.3);
  transition: all var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
}

.dark-toggle-btn:hover {
  transform: translateY(-4px) rotate(15deg);
  box-shadow: 0 8px 24px rgba(43, 90, 140, 0.4);
}

@media (max-width: 640px) {
  .dark-toggle-btn {
    bottom: 80px;
    right: 20px;
    width: 44px;
    height: 44px;
    font-size: 1.1rem;
  }
}

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

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

::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, var(--primary-light), var(--primary));
  border-radius: 8px;
  border: 2px solid var(--bg);
}

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

/* ---------- 选中样式 ---------- */
::selection {
  background: rgba(43, 90, 140, 0.2);
  color: var(--primary-dark);
}

/* ---------- 无障碍与细节 ---------- */
:focus-visible {
  outline: 3px solid rgba(43, 90, 140, 0.4);
  outline-offset: 2px;
  border-radius: 4px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}