/* 全局重置与基础样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: linear-gradient(135deg, #f0f4f8 0%, #e2e8f0 100%);
  color: #1a1a2e;
  line-height: 1.6;
  transition: background 0.4s, color 0.4s;
}

/* 暗色模式 */
.dark body {
  background: linear-gradient(135deg, #0b1622 0%, #1a2536 100%);
  color: #cfd8e6;
}

/* 头部导航 */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px) saturate(180%);
  -webkit-backdrop-filter: blur(12px) saturate(180%);
  border-bottom: 1px solid rgba(224, 228, 234, 0.6);
  transition: background 0.4s, border-color 0.4s;
}

.dark header {
  background: rgba(10, 20, 30, 0.85);
  border-color: rgba(42, 58, 74, 0.6);
}

.main-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0.8rem 1.5rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  font-weight: 700;
  color: #1a3b5c;
  font-size: 1.4rem;
  transition: color 0.3s, transform 0.3s;
}

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

.dark .logo {
  color: #f0c040;
}

.logo svg {
  transition: transform 0.4s ease;
}

.logo:hover svg {
  transform: rotate(-5deg) scale(1.1);
}

.nav-list {
  display: flex;
  gap: 1.8rem;
  list-style: none;
}

.nav-list a {
  text-decoration: none;
  color: #1a3b5c;
  font-weight: 500;
  padding: 0.3rem 0;
  position: relative;
  transition: color 0.3s;
}

.dark .nav-list a {
  color: #cfd8e6;
}

.nav-list a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: #f0c040;
  transition: width 0.3s ease;
}

.nav-list a:hover::after,
.nav-list a.active::after {
  width: 100%;
}

.nav-list a.active {
  color: #f0c040;
  font-weight: 600;
}

.dark-mode-toggle,
.mobile-menu-btn {
  background: rgba(26, 59, 92, 0.08);
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  padding: 0.4rem 0.6rem;
  border-radius: 30px;
  color: #1a3b5c;
  transition: background 0.3s, transform 0.3s;
}

.dark-mode-toggle:hover,
.mobile-menu-btn:hover {
  background: rgba(240, 192, 64, 0.2);
  transform: scale(1.1);
}

.dark .dark-mode-toggle,
.dark .mobile-menu-btn {
  color: #f0c040;
  background: rgba(240, 192, 64, 0.1);
}

.mobile-menu-btn {
  display: none;
}

/* 移动端导航 */
@media (max-width: 768px) {
  .nav-list {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.97);
    backdrop-filter: blur(10px);
    padding: 1.2rem;
    gap: 0.8rem;
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.08);
    border-radius: 0 0 20px 20px;
    animation: slideDown 0.3s ease;
  }

  .dark .nav-list {
    background: rgba(10, 20, 30, 0.97);
  }

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

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

  .nav-list a {
    padding: 0.6rem 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  }

  .dark .nav-list a {
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 英雄区域 */
.hero {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 2rem auto;
  padding: 3rem 1.5rem;
  gap: 2rem;
  background: linear-gradient(135deg, rgba(26, 59, 92, 0.03) 0%, rgba(240, 192, 64, 0.05) 100%);
  border-radius: 40px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(240, 192, 64, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-content {
  flex: 1 1 400px;
  position: relative;
  z-index: 2;
}

.hero h1 {
  font-size: 2.8rem;
  font-weight: 800;
  color: #0b1a2f;
  margin-bottom: 1rem;
  line-height: 1.2;
  background: linear-gradient(135deg, #0b1a2f 0%, #1a3b5c 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.dark .hero h1 {
  background: linear-gradient(135deg, #e8edf5 0%, #f0c040 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.2rem;
  color: #2e3b4e;
  margin-bottom: 2.5rem;
  opacity: 0.9;
}

.dark .hero p {
  color: #b0c4d9;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.btn {
  display: inline-block;
  padding: 0.9rem 2.2rem;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.btn.primary {
  background: linear-gradient(135deg, #1a3b5c, #2a5a8a);
  color: white;
  box-shadow: 0 4px 15px rgba(26, 59, 92, 0.3);
}

.btn.primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(26, 59, 92, 0.4);
}

.btn.secondary {
  background: linear-gradient(135deg, #f0c040, #f5d06a);
  color: #0b1a2f;
  box-shadow: 0 4px 15px rgba(240, 192, 64, 0.3);
}

.btn.secondary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(240, 192, 64, 0.4);
}

.hero-visual {
  flex: 1 1 300px;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  z-index: 2;
}

.hero-visual svg {
  max-width: 100%;
  height: auto;
  filter: drop-shadow(0 8px 20px rgba(0, 0, 0, 0.06));
  transition: transform 0.6s ease;
}

.hero-visual:hover svg {
  transform: scale(1.03) rotate(1deg);
}

/* 通用section */
section {
  max-width: 1200px;
  margin: 4rem auto;
  padding: 0 1.5rem;
  animation: fadeInUp 0.6s ease;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

h2 {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 2rem;
  color: #0b1a2f;
  border-left: 5px solid #f0c040;
  padding-left: 1.2rem;
  position: relative;
}

.dark h2 {
  color: #e8edf5;
}

h2::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 1.2rem;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, #f0c040, transparent);
  border-radius: 4px;
}

/* 卡片网格 */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.8rem;
}

.card {
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-radius: 24px;
  padding: 2rem 1.8rem;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.04);
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  border: 1px solid rgba(255, 255, 255, 0.3);
  position: relative;
  overflow: hidden;
}

.dark .card {
  background: rgba(30, 42, 58, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.05);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #1a3b5c, #f0c040, #1a3b5c);
  background-size: 200% 100%;
  transition: background-position 0.6s;
}

.card:hover::before {
  background-position: 100% 0;
}

.card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.08);
}

.dark .card:hover {
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.3);
}

.card h3 {
  margin-bottom: 0.8rem;
  font-size: 1.4rem;
  color: #1a3b5c;
  transition: color 0.3s;
}

.dark .card h3 {
  color: #f0c040;
}

.card p {
  color: #4a5568;
  margin-bottom: 1.2rem;
}

.dark .card p {
  color: #a0b4c8;
}

.card-link {
  display: inline-block;
  padding: 0.5rem 1.4rem;
  background: linear-gradient(135deg, #1a3b5c, #2a5a8a);
  color: white;
  text-decoration: none;
  border-radius: 30px;
  font-weight: 500;
  font-size: 0.9rem;
  transition: all 0.3s;
  box-shadow: 0 2px 8px rgba(26, 59, 92, 0.2);
}

.card-link:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(26, 59, 92, 0.3);
  background: linear-gradient(135deg, #2a5a8a, #1a3b5c);
}

/* 统计数字 */
.stats {
  display: flex;
  flex-wrap: wrap;
  gap: 2.5rem;
  justify-content: center;
  margin: 2.5rem 0;
  padding: 2rem;
  background: rgba(255, 255, 255, 0.5);
  backdrop-filter: blur(8px);
  border-radius: 30px;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.dark .stats {
  background: rgba(30, 42, 58, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.stat {
  text-align: center;
  font-size: 1.6rem;
  font-weight: 700;
  color: #1a3b5c;
  transition: transform 0.3s;
}

.dark .stat {
  color: #f0c040;
}

.stat:hover {
  transform: scale(1.05);
}

.stat span:first-child {
  display: block;
  font-size: 2.8rem;
  background: linear-gradient(135deg, #1a3b5c, #f0c040);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.dark .stat span:first-child {
  background: linear-gradient(135deg, #f0c040, #e8edf5);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat span:last-child {
  font-size: 1rem;
  font-weight: 400;
  color: #4a5568;
  display: block;
  margin-top: 0.3rem;
}

.dark .stat span:last-child {
  color: #a0b4c8;
}

/* 文章列表 */
.article-list article {
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
  padding: 1rem 0;
  transition: padding-left 0.3s;
}

.dark .article-list article {
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.article-list article:hover {
  padding-left: 0.8rem;
}

.article-list a {
  text-decoration: none;
  color: #1a3b5c;
  transition: color 0.3s;
}

.dark .article-list a {
  color: #b0c4d9;
}

.article-list a:hover {
  color: #f0c040;
}

.article-list h3 {
  font-size: 1.1rem;
  font-weight: 500;
}

/* 步骤列表 */
.steps {
  list-style: none;
  counter-reset: step;
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(10px);
  padding: 2.5rem;
  border-radius: 30px;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.dark .steps {
  background: rgba(30, 42, 58, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.steps li {
  counter-increment: step;
  padding: 1rem 0 1rem 3rem;
  position: relative;
  font-size: 1.05rem;
  border-bottom: 1px solid rgba(0, 0, 0, 0.04);
  transition: transform 0.3s, padding-left 0.3s;
}

.dark .steps li {
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

.steps li:hover {
  transform: translateX(6px);
  padding-left: 3.5rem;
}

.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 1rem;
  width: 2rem;
  height: 2rem;
  background: linear-gradient(135deg, #1a3b5c, #2a5a8a);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
  transition: transform 0.3s, background 0.3s;
}

.steps li:hover::before {
  transform: scale(1.1);
  background: linear-gradient(135deg, #f0c040, #f5d06a);
  color: #0b1a2f;
}

.steps li:last-child {
  border-bottom: none;
}

/* FAQ 手风琴 */
.faq-list {
  margin: 1.5rem 0;
  border-radius: 24px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.5);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.dark .faq-list {
  background: rgba(30, 42, 58, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.faq-item {
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  transition: background 0.3s;
}

.dark .faq-item {
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-item:hover {
  background: rgba(240, 192, 64, 0.03);
}

.faq-question {
  background: none;
  border: none;
  width: 100%;
  text-align: left;
  padding: 1.2rem 1.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: #1a3b5c;
  transition: color 0.3s, padding-left 0.3s;
}

.dark .faq-question {
  color: #e0e8f0;
}

.faq-question:hover {
  color: #f0c040;
  padding-left: 2rem;
}

.faq-question .icon {
  font-size: 1.6rem;
  font-weight: 300;
  transition: transform 0.3s;
  color: #1a3b5c;
}

.dark .faq-question .icon {
  color: #f0c040;
}

.faq-question[aria-expanded="true"] .icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), padding 0.3s;
  padding: 0 1.5rem;
  background: rgba(255, 255, 255, 0.3);
}

.dark .faq-answer {
  background: rgba(0, 0, 0, 0.1);
}

.faq-answer p {
  padding: 0.8rem 0 1.2rem;
  color: #4a5568;
  line-height: 1.7;
}

.dark .faq-answer p {
  color: #a0b4c8;
}

/* 联系区域 */
.contact {
  background: rgba(255, 255, 255, 0.6);
  backdrop-filter: blur(12px);
  padding: 2.5rem;
  border-radius: 30px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  text-align: center;
}

.dark .contact {
  background: rgba(30, 42, 58, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.contact p {
  font-size: 1.1rem;
  margin-bottom: 0.6rem;
  color: #2e3b4e;
}

.dark .contact p {
  color: #b0c4d9;
}

/* 页脚 */
footer {
  background: linear-gradient(135deg, #0b1a2f, #1a2a3e);
  color: #aab9ce;
  padding: 2.5rem 1.5rem;
  text-align: center;
  margin-top: 4rem;
  position: relative;
}

footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, #1a3b5c, #f0c040, #1a3b5c);
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
}

.footer-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 2rem;
  margin-bottom: 1.2rem;
}

.footer-links a {
  color: #f0c040;
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s, transform 0.3s;
  position: relative;
}

.footer-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: #f0c040;
  transition: width 0.3s;
}

.footer-links a:hover {
  color: #ffd966;
  transform: translateY(-1px);
}

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

footer p {
  font-size: 0.9rem;
  opacity: 0.8;
}

/* 返回顶部 */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 52px;
  height: 52px;
  background: linear-gradient(135deg, #1a3b5c, #2a5a8a);
  color: white;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(26, 59, 92, 0.3);
  z-index: 99;
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  border: none;
  outline: none;
}

.dark .back-to-top {
  background: linear-gradient(135deg, #f0c040, #f5d06a);
  color: #0b1a2f;
  box-shadow: 0 6px 20px rgba(240, 192, 64, 0.3);
}

.back-to-top:hover {
  transform: translateY(-6px) scale(1.08);
  box-shadow: 0 10px 30px rgba(26, 59, 92, 0.4);
}

.dark .back-to-top:hover {
  box-shadow: 0 10px 30px rgba(240, 192, 64, 0.4);
}

/* 响应式调整 */
@media (max-width: 768px) {
  .hero {
    padding: 2rem 1.2rem;
    margin: 1rem;
    border-radius: 24px;
  }

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

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

  h2 {
    font-size: 1.6rem;
  }

  .stats {
    gap: 1.5rem;
    padding: 1.5rem;
  }

  .stat span:first-child {
    font-size: 2rem;
  }

  .card-grid {
    grid-template-columns: 1fr;
    gap: 1.2rem;
  }

  .card {
    padding: 1.5rem;
  }

  .steps {
    padding: 1.5rem;
  }

  .steps li {
    padding-left: 2.5rem;
    font-size: 0.95rem;
  }

  .faq-question {
    padding: 1rem 1.2rem;
    font-size: 1rem;
  }

  .faq-answer {
    padding: 0 1.2rem;
  }

  .contact {
    padding: 1.8rem;
  }

  .footer-links {
    gap: 1.2rem;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
    font-size: 1.4rem;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.6rem;
  }

  .btn {
    padding: 0.7rem 1.6rem;
    font-size: 0.9rem;
  }

  .stat span:first-child {
    font-size: 1.6rem;
  }
}

/* 滚动动画支持：针对需要滚动触发动画的元素 */
@media (prefers-reduced-motion: no-preference) {
  section {
    opacity: 0;
    animation: fadeInUp 0.7s ease forwards;
  }

  section:nth-child(2) { animation-delay: 0.1s; }
  section:nth-child(3) { animation-delay: 0.2s; }
  section:nth-child(4) { animation-delay: 0.3s; }
  section:nth-child(5) { animation-delay: 0.4s; }
  section:nth-child(6) { animation-delay: 0.5s; }
  section:nth-child(7) { animation-delay: 0.6s; }
  section:nth-child(8) { animation-delay: 0.7s; }
  section:nth-child(9) { animation-delay: 0.8s; }
}

/* 选择样式 */
::selection {
  background: #f0c040;
  color: #0b1a2f;
}

/* 滚动条 */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: #f0f4f8;
}

.dark ::-webkit-scrollbar-track {
  background: #111a26;
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(135deg, #1a3b5c, #2a5a8a);
  border-radius: 10px;
}

.dark ::-webkit-scrollbar-thumb {
  background: linear-gradient(135deg, #f0c040, #f5d06a);
}

::-webkit-scrollbar-thumb:hover {
  background: #1a3b5c;
}

.dark ::-webkit-scrollbar-thumb:hover {
  background: #f0c040;
}