/* ========== Reset & Base ========== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --blue-dark: #004a99;
  --blue-primary: #00529b;
  --blue-header: #003d7a;
  --blue-light: #0066cc;
  --blue-border: #b8d4f0;
  --blue-bg-light: #eef4ff;
  --blue-footer-bottom: #003366;
  --gold: #f5a623;
  --text-dark: #333333;
  --text-gray: #666666;
  --text-light-gray: #999999;
  --white: #ffffff;
  --container-width: 1200px;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  background: var(--white);
  min-width: 1200px;
}

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

ul {
  list-style: none;
}

.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ========== Shared Section Header ========== */
.section-header {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-bottom: 24px;
}

.section-icon {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.section-icon svg {
  width: 20px;
  height: 20px;
}

.section-icon-blue {
  background: linear-gradient(135deg, #0066cc, #004a99);
  color: var(--white);
}

.section-icon-white {
  background: rgba(255, 255, 255, 0.2);
  color: var(--white);
}

.section-icon-img {
  width: auto;
  height: auto;
  border-radius: 0;
  background: none;
}

.section-icon-img img {
  display: block;
  width: 52px;
  height: 52px;
  object-fit: contain;
}

.section-title-cn {
  font-size: 22px;
  font-weight: 700;
  color: var(--blue-primary);
  line-height: 1;
}

.section-header-white .section-title-cn {
  color: var(--white);
}

.section-title-en {
  font-size: 13px;
  color: var(--text-light-gray);
  letter-spacing: 1px;
  font-weight: 400;
  margin-left: 2px;
}

.section-header-white .section-title-en {
  color: rgba(255, 255, 255, 0.5);
}

.arrow-btn {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 1px solid var(--blue-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--blue-primary);
  transition: background 0.2s;
  flex-shrink: 0;
}

.arrow-btn svg {
  width: 16px;
  height: 16px;
}

.arrow-btn-sm {
  width: 28px;
  height: 28px;
  margin-left: auto;
}

.arrow-btn-sm svg {
  width: 14px;
  height: 14px;
}

/* ========== Logo ========== */
.logo-circle {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.8);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  background: rgba(255, 255, 255, 0.1);
}

.logo-circle-sm {
  width: 48px;
  height: 48px;
}

.logo-text {
  font-size: 14px;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 1px;
}

.logo-info .logo-cn {
  font-size: 14px;
  font-weight: 600;
  color: var(--white);
  line-height: 1.4;
}

.logo-info .logo-en {
  font-size: 9px;
  color: rgba(255, 255, 255, 0.75);
  letter-spacing: 0.5px;
  line-height: 1.3;
}

/* ========== Header & Hero ========== */
.site-header {
  position: relative;
}

.hero-banner {
  position: relative;
  width: 100%;
  height: 480px;
  background: url("../images//top-banner.png") center top / cover no-repeat;
  overflow: hidden;
}

.hero-banner::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 80px;
  background: linear-gradient(to bottom, transparent, #f8f9fb);
  pointer-events: none;
  z-index: 1;
}

.header-inner {
  position: relative;
  z-index: 2;
  height: 100%;
}

.header-top {
  max-width: var(--container-width);
  width: 100%;
  margin: 0 auto;
  padding: 18px 20px 0;
  display: flex;
  justify-content: flex-end;
}

.header-search {
  flex-shrink: 0;
}

.header-search form {
  margin: 0;
}

.search-box {
  display: flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.7);
  border-radius: 20px;
  overflow: hidden;
  width: 260px;
  height: 36px;
  padding-left: 14px;
  backdrop-filter: blur(4px);
}

.search-icon {
  width: 16px;
  height: 16px;
  color: var(--white);
  flex-shrink: 0;
}

.search-box input {
  border: none;
  outline: none;
  flex: 1;
  padding: 0 10px;
  font-size: 13px;
  background: transparent;
  color: var(--white);
  min-width: 0;
}

.search-box input::placeholder {
  color: rgba(255, 255, 255, 0.6);
}

.search-box button {
  background: var(--blue-primary);
  color: var(--white);
  border: none;
  padding: 0 16px;
  height: 100%;
  font-size: 13px;
  cursor: pointer;
  font-family: inherit;
  flex-shrink: 0;
  border-radius: 0 18px 18px 0;
  transition: background 0.2s;
}

.search-box button:hover {
  background: var(--blue-dark);
}

.main-nav {
  max-width: var(--container-width);
  width: 100%;
  margin: 108px auto 0;
  padding: 0 20px;
}

.nav-list {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  gap: 88px;
  list-style: none;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: inline-block;
  color: rgba(255, 255, 255, 0.9);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 4px;
  padding: 6px 4px;
  position: relative;
  transition: color 0.25s ease, transform 0.25s ease;
  transform-origin: center bottom;
}

.nav-link:hover,
.nav-item.has-submenu:hover > .nav-link {
  color: var(--white);
  transform: scale(1.15);
}

.nav-link.active {
  color: var(--white);
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 28px;
  height: 2px;
  background: var(--white);
  border-radius: 1px;
}

.nav-link.active:hover {
  transform: scale(1.15);
}

.nav-link.active:hover::after {
  transform: translateX(-50%) scale(0.87);
}

.submenu {
  position: absolute;
  top: calc(100% + 14px);
  left: 50%;
  transform: translateX(-50%) translateY(-18px);
  min-width: 168px;
  padding: 10px 0;
  background: rgba(255, 255, 255, 0.96);
  border-radius: 6px;
  box-shadow: 0 8px 24px rgba(0, 45, 98, 0.18);
  list-style: none;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition:
    opacity 0.4s ease,
    transform 0.5s cubic-bezier(0.22, 1, 0.36, 1),
    visibility 0.4s ease;
  z-index: 20;
}

.submenu::before {
  content: "";
  position: absolute;
  top: -6px;
  left: 50%;
  transform: translateX(-50%) rotate(45deg);
  width: 12px;
  height: 12px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: -2px -2px 4px rgba(0, 45, 98, 0.06);
  opacity: 0;
  transition: opacity 0.35s ease 0.1s;
}

.nav-item.has-submenu::after {
  content: "";
  position: absolute;
  top: 100%;
  left: -10px;
  right: -10px;
  height: 18px;
}

.nav-item.has-submenu:hover .submenu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

.nav-item.has-submenu:hover .submenu::before {
  opacity: 1;
}

.submenu li {
  opacity: 0;
  transform: translateY(-10px);
  transition:
    opacity 0.35s ease,
    transform 0.4s cubic-bezier(0.22, 1, 0.36, 1);
}

.nav-item.has-submenu:hover .submenu li {
  opacity: 1;
  transform: translateY(0);
}

.nav-item.has-submenu:hover .submenu li:nth-child(1) { transition-delay: 0.08s; }
.nav-item.has-submenu:hover .submenu li:nth-child(2) { transition-delay: 0.11s; }
.nav-item.has-submenu:hover .submenu li:nth-child(3) { transition-delay: 0.14s; }
.nav-item.has-submenu:hover .submenu li:nth-child(4) { transition-delay: 0.17s; }
.nav-item.has-submenu:hover .submenu li:nth-child(5) { transition-delay: 0.2s; }

.submenu.submenu-large {
  min-width: 480px;
  padding: 10px 0;
  overflow: visible;
}

.submenu.submenu-large > ul {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  max-height: min(260px, calc(100vh - 220px));
  overflow-y: auto;
  overflow-x: hidden;
  list-style: none;
  margin: 0;
  padding: 0;
}

.submenu.submenu-large li a {
  padding: 10px 18px;
  font-size: 14px;
}

.nav-item.has-submenu:hover .submenu.submenu-large li {
  transition-delay: 0.1s;
}

.submenu.submenu-large > ul::-webkit-scrollbar {
  width: 4px;
}

.submenu.submenu-large > ul::-webkit-scrollbar-thumb {
  background: rgba(0, 82, 155, 0.25);
  border-radius: 2px;
}

.submenu li a {
  display: block;
  padding: 10px 22px;
  font-size: 14px;
  color: var(--text-dark);
  letter-spacing: 1px;
  white-space: nowrap;
  transition: color 0.2s ease, background 0.2s ease, padding-left 0.2s ease;
}

.submenu li a:hover {
  color: var(--blue-primary);
  background: rgba(0, 82, 155, 0.06);
  padding-left: 28px;
}

/* ========== Footer ========== */
.site-footer {
  margin-top: 0;
  line-height: 0;
}

.site-footer img {
  display: block;
  width: 100%;
  height: auto;
}