/* ===== 海豚跨境电商官网 - 公共样式 ===== */
:root {
  --primary: #004EA3;
  --primary-dark: #003880;
  --primary-light: #1a6bbf;
  --accent: #00C4E0;
  --accent2: #FF6B35;
  --text-dark: #1a1a2e;
  --text-gray: #5a6478;
  --text-light: #8896a8;
  --bg-white: #ffffff;
  --bg-light: #f5f8ff;
  --bg-dark: #0a1628;
  --border: #e0e8f5;
  --shadow: 0 8px 32px rgba(0,78,163,0.12);
  --shadow-hover: 0 16px 48px rgba(0,78,163,0.22);
  --radius: 12px;
  --radius-lg: 20px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  color: var(--text-dark);
  background: var(--bg-white);
  line-height: 1.6;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* ===== 通用布局 ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 40px; }
.section { padding: 90px 0; }
.section-sm { padding: 60px 0; }
.text-center { text-align: center; }

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-tag {
  display: inline-block;
  background: rgba(0,78,163,0.08);
  color: var(--primary);
  font-size: 13px;
  font-weight: 600;
  padding: 6px 16px;
  border-radius: 50px;
  letter-spacing: 0.05em;
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 700;
  color: var(--text-dark);
  line-height: 1.25;
  margin-bottom: 16px;
}

.section-title span { color: var(--primary); }

.section-desc {
  font-size: 17px;
  color: var(--text-gray);
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.75;
}

.section-sub {
  font-size: 16px;
  color: var(--text-gray);
  max-width: 560px;
  margin: -8px auto 0;
  line-height: 1.75;
}

/* ===== 导航栏 ===== */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  height: 72px;
  display: flex;
  align-items: center;
  transition: all 0.3s ease;
  background: transparent;
}

.navbar.scrolled {
  background: rgba(255,255,255,0.97);
  box-shadow: 0 2px 20px rgba(0,78,163,0.1);
  backdrop-filter: blur(16px);
}

.navbar.dark-nav {
  background: rgba(255,255,255,0.97);
  box-shadow: 0 2px 20px rgba(0,78,163,0.1);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 40px;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  z-index: 1001;
}

.logo-icon {
  width: 42px; height: 42px;
 
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  flex-shrink: 0;
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-main {
  font-size: 18px;
  font-weight: 700;
  color: #fff;
  line-height: 1;
  transition: color 0.3s;
}

.logo-sub {
  font-size: 10px;
  color: rgba(255,255,255,0.7);
  letter-spacing: 0.1em;
  font-weight: 500;
  transition: color 0.3s;
}

.navbar.scrolled .logo-main,
.navbar.dark-nav .logo-main { color: var(--primary); }
.navbar.scrolled .logo-sub,
.navbar.dark-nav .logo-sub { color: var(--text-light); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-links a {
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: 8px;
  transition: all 0.25s;
  color: rgba(255,255,255,0.9);
}

.navbar.scrolled .nav-links a,
.navbar.dark-nav .nav-links a { color: var(--text-dark); }

.nav-links a:hover,
.nav-links a.active {
  background: var(--primary);
  color: #fff !important;
}

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

.btn-nav {
  padding: 9px 24px;
  background: var(--accent2);
  color: #fff;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.25s;
}

.btn-nav:hover { background: #e55a28; transform: translateY(-1px); }

.navbar.scrolled .btn-nav,
.navbar.dark-nav .btn-nav { background: var(--accent2); color: #fff; }

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  z-index: 1001;
  background: none;
  border: none;
}

.mobile-menu-btn span {
  width: 22px; height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: all 0.3s;
}

.navbar.scrolled .mobile-menu-btn span,
.navbar.dark-nav .mobile-menu-btn span { background: var(--text-dark); }

.mobile-menu-btn.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.mobile-menu-btn.open span:nth-child(2) { opacity: 0; }
.mobile-menu-btn.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

.mobile-menu {
  display: none;
  position: fixed;
  top: 72px; left: 0; right: 0;
  background: rgba(255,255,255,0.98);
  padding: 20px 40px;
  flex-direction: column;
  gap: 4px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.1);
  backdrop-filter: blur(20px);
}

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

.mobile-menu a {
  text-decoration: none;
  color: var(--text-dark);
  font-size: 15px;
  font-weight: 500;
  padding: 12px 16px;
  border-radius: 8px;
  transition: all 0.25s;
}

.mobile-menu a:hover,
.mobile-menu a.active {
  background: var(--primary);
  color: #fff;
}

/* ===== 页面横幅（子页面） ===== */
.page-banner {
  padding: 140px 40px 80px;
  background: linear-gradient(135deg, #001f4d 0%, #004EA3 50%, #0072cc 100%);
  position: relative;
  overflow: hidden;
  text-align: center;
}

.page-banner::before {
  content: '';
  position: absolute; inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.04'%3E%3Ccircle cx='30' cy='30' r='2'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.page-banner h1 {
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 800;
  color: #fff;
  position: relative;
  margin-bottom: 16px;
}

.page-banner p {
  font-size: 17px;
  color: rgba(255,255,255,0.8);
  position: relative;
  max-width: 500px;
  margin: 0 auto;
  line-height: 1.7;
}

.page-banner-wave {
  position: absolute;
  bottom: -2px; left: 0; right: 0;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  border: none;
  transition: all 0.25s;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0,78,163,0.4);
}

.btn-sm {
  padding: 8px 18px;
  font-size: 13px;
  border-radius: 8px;
}

.btn-white {
  background: #fff;
  color: var(--primary);
}

.btn-white:hover {
  background: #f0f5ff;
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border: 2px solid rgba(255,255,255,0.5);
}

.btn-outline:hover {
  background: rgba(255,255,255,0.1);
  border-color: #fff;
  transform: translateY(-2px);
}

.btn-primary-white {
  padding: 14px 32px;
  background: #fff;
  color: var(--primary);
  border-radius: 30px;
  font-size: 15px;
  font-weight: 700;
  text-decoration: none;
  transition: all .3s;
  box-shadow: 0 8px 24px rgba(0,0,0,0.2);
  display: inline-block;
}

.btn-primary-white:hover { transform: translateY(-2px); box-shadow: 0 12px 32px rgba(0,0,0,0.3); }

.btn-outline-white {
  padding: 14px 32px;
  background: transparent;
  border: 2px solid rgba(255,255,255,0.6);
  color: #fff;
  border-radius: 30px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: all .3s;
  display: inline-block;
}

.btn-outline-white:hover { background: rgba(255,255,255,0.15); border-color: #fff; }

/* ===== 卡片 ===== */
.card {
  background: #fff;
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow);
  transition: all 0.3s;
  border: 1px solid var(--border);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: rgba(0,78,163,0.2);
}

/* ===== 页脚 ===== */
.footer {
  background: var(--bg-dark);
  color: rgba(255,255,255,0.7);
  padding: 70px 0 30px;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 40px;
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1fr;
  gap: 50px;
  margin-bottom: 50px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
}

.footer-logo .logo-icon {
  background: linear-gradient(135deg, var(--primary), var(--accent));
}

.footer-logo .logo-main { color: #fff; font-size: 20px; }
.footer-logo .logo-sub { color: rgba(255,255,255,0.5); }

.footer-desc {
  font-size: 14px;
  line-height: 1.8;
  margin-bottom: 24px;
  color: rgba(255,255,255,0.6);
}

.footer-social {
  display: flex;
  gap: 12px;
}

.social-link {
  padding: 6px 14px;
  border-radius: 8px;
  background: rgba(255,255,255,0.08);
  font-size: 13px;
  color: rgba(255,255,255,0.7);
  transition: all 0.25s;
}

.social-link:hover { background: var(--primary); color: #fff; }

.footer-links {
  display: contents;
}

.footer-col h4 {
  color: #fff;
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 20px;
}

.footer-col a {
  display: block;
  color: rgba(255,255,255,0.55);
  font-size: 14px;
  margin-bottom: 12px;
  transition: color 0.25s;
}

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

.footer-bottom {
  max-width: 1200px;
  margin: 0 auto;
  padding: 28px 40px 0;
  border-top: 1px solid rgba(255,255,255,0.08);
  font-size: 13px;
  color: rgba(255,255,255,0.4);
  text-align: center;
}

/* ===== 回到顶部 ===== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px; height: 48px;
  background: var(--primary);
  color: #fff;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(0,78,163,0.4);
  opacity: 0;
  transform: translateY(16px);
  transition: all 0.3s;
  z-index: 999;
  text-decoration: none;
}

.back-to-top.visible { opacity: 1; transform: translateY(0); }
.back-to-top:hover { background: var(--primary-dark); transform: translateY(-2px); }

/* ===== 入场动画 ===== */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-up.visible { opacity: 1; transform: translateY(0); }
.fade-up:nth-child(1) { transition-delay: 0.05s; }
.fade-up:nth-child(2) { transition-delay: 0.15s; }
.fade-up:nth-child(3) { transition-delay: 0.25s; }
.fade-up:nth-child(4) { transition-delay: 0.35s; }
.fade-up:nth-child(5) { transition-delay: 0.45s; }
.fade-up:nth-child(6) { transition-delay: 0.55s; }

/* ===== Tab 切换 ===== */
.tab-group { margin-top: 40px; }

.tab-btns {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 40px;
}

.tab-btn {
  padding: 12px 28px;
  border: 2px solid var(--border);
  border-radius: 30px;
  background: #fff;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-gray);
  cursor: pointer;
  transition: all 0.3s;
}

.tab-btn:hover { border-color: var(--primary); color: var(--primary); }

.tab-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.tab-pane { display: none; }
.tab-pane.active { display: block; }

/* ===== FAQ ===== */
.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 12px;
  transition: all 0.3s;
}

.faq-item:hover { border-color: rgba(0,78,163,0.3); }

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

.faq-q {
  padding: 20px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
  color: var(--text-dark);
  gap: 16px;
}

.faq-q::after {
  content: '+';
  font-size: 20px;
  color: var(--primary);
  font-weight: 300;
  flex-shrink: 0;
  transition: transform 0.3s;
}

.faq-item.open .faq-q::after { content: '−'; }

.faq-a {
  padding: 0 24px 20px;
  font-size: 14px;
  color: var(--text-gray);
  line-height: 1.8;
  display: none;
}

.faq-item.open .faq-a { display: block; }

/* ===== 新闻筛选 ===== */
.filter-bar {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 8px 20px;
  border: 2px solid var(--border);
  border-radius: 30px;
  background: #fff;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-gray);
  cursor: pointer;
  transition: all 0.3s;
}

.filter-btn:hover { border-color: var(--primary); color: var(--primary); }
.filter-btn.active { background: var(--primary); border-color: var(--primary); color: #fff; }

/* ===== 时间轴 ===== */
.timeline { position: relative; padding-left: 40px; }

.timeline::before {
  content: '';
  position: absolute;
  left: 15px; top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--primary), var(--accent));
}

.timeline-item {
  position: relative;
  padding-bottom: 40px;
  padding-left: 30px;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -29px; top: 6px;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--primary);
  border: 3px solid #fff;
  box-shadow: 0 0 0 3px var(--primary);
}

.timeline-item .t-date {
  font-size: 13px;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 6px;
}

.timeline-item .t-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 4px;
}

.timeline-item .t-desc {
  font-size: 14px;
  color: var(--text-gray);
  line-height: 1.7;
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .container { padding: 0 24px; }
  .footer-inner { grid-template-columns: 1fr 1fr; gap: 36px; }
  .nav-links { display: none; }
  .nav-actions { display: none; }
  .mobile-menu-btn { display: flex; }
  .nav-inner { padding: 0 24px; }
  .footer-inner { padding: 0 24px; }
  .footer-bottom { padding: 28px 24px 0; }
  .page-banner { padding: 120px 24px 60px; }
}

@media (max-width: 768px) {
  .navbar { height: 64px; }
  .mobile-menu-btn { display: flex; }
  .mobile-menu { padding: 20px 24px; top: 64px; }
  .container { padding: 0 20px; }
  .section { padding: 64px 0; }
  .section-header { margin-bottom: 40px; }
  .footer-inner { grid-template-columns: 1fr; gap: 28px; }
  .btn { padding: 12px 24px; font-size: 14px; }
  .tab-btn { padding: 10px 20px; font-size: 13px; }
  .timeline { padding-left: 30px; }
}

@media (max-width: 480px) {
  .back-to-top { bottom: 20px; right: 20px; width: 42px; height: 42px; font-size: 16px; }
}