/* ===== CSS Variables ===== */
:root {
  --primary:        #0a2d6e;
  --primary-dark:   #061d4a;
  --primary-light:  #1555c8;
  --accent:         #0098d4;
  --accent-hover:   #0077aa;
  --text:           #1a1a1a;
  --text-secondary: #555;
  --text-light:     #888;
  --bg-light:       #f4f6fb;
  --border:         #dde3ef;
  --white:          #ffffff;
  --shadow:         0 2px 20px rgba(10,45,110,.08);
  --shadow-hover:   0 8px 32px rgba(10,45,110,.18);
  --transition:     .3s ease;
  --radius:         6px;
  --radius-lg:      12px;
  --font:           'PingFang SC','Microsoft YaHei','Noto Sans SC',sans-serif;
  --nav-height:     72px;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--text);
  line-height: 1.6;
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: var(--font); }
input, textarea, select { font-family: var(--font); }

/* ===== Layout ===== */
.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}
.container--wide {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 40px;
}
.row {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
}

/* ===== Section Common ===== */
.section { padding: 80px 0; }
.section--gray { background: var(--bg-light); }
.section__header {
  text-align: center;
  margin-bottom: 52px;
}
.section__tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent);
  background: rgba(0,152,212,.08);
  padding: 4px 14px;
  border-radius: 20px;
  margin-bottom: 14px;
}
.section__title {
  font-size: clamp(24px, 2.4vw, 34px);
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 14px;
  line-height: 1.3;
}
.section__subtitle {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto;
}
.section__divider {
  width: 60px;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
  margin: 0 auto 20px;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  transition: all var(--transition);
  white-space: nowrap;
}
.btn--primary {
  background: var(--accent);
  color: var(--white);
}
.btn--primary:hover {
  background: var(--accent-hover);
  color: var(--white);
}
.btn--outline {
  border: 2px solid rgba(0,152,212,.5);
  color: var(--accent);
}
.btn--outline:hover {
  background: rgba(0,152,212,.07);
}
.btn--outline-dark {
  border: 2px solid var(--primary);
  color: var(--primary);
}
.btn--outline-dark:hover {
  background: var(--primary);
  color: var(--white);
}
.btn--sm { padding: 8px 20px; font-size: 13px; }
.btn--lg { padding: 15px 36px; font-size: 16px; }

/* ===== Cards ===== */
.card {
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: box-shadow var(--transition), transform var(--transition);
}
.card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}
.card__img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}
.card__img-placeholder {
  width: 100%;
  height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.card__body { padding: 24px; }
.card__title {
  font-size: 18px;
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 10px;
}
.card__text {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}
.card__link {
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: gap var(--transition);
}
.card__link:hover { gap: 10px; }

/* ===== Page Hero (sub-pages) ===== */
.page-hero {
  height: 280px;
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 50%, var(--primary-light) 100%);
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  margin-top: var(--nav-height);
}
.page-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 30% 50%, rgba(21,85,200,.3) 0%, transparent 50%),
    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='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}
.page-hero__content {
  position: relative;
  z-index: 1;
}
.page-hero__title {
  font-size: clamp(28px, 3vw, 42px);
  font-weight: 700;
  color: var(--white);
  margin-bottom: 12px;
}
.page-hero__breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: rgba(255,255,255,.7);
}
.page-hero__breadcrumb a:hover { color: var(--white); }
.page-hero__breadcrumb span { color: rgba(255,255,255,.4); }

/* ===== Utilities ===== */
.text-center { text-align: center; }
.text-primary { color: var(--primary); }

/* ===== Header ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  overflow: visible;
  background: rgba(255,255,255,.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--transition);
}
.site-header.scrolled {
  box-shadow: 0 4px 24px rgba(10,45,110,.14);
}
.header-inner {
  display: flex;
  align-items: center;
  height: var(--nav-height);
  gap: 40px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.logo-mark {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.logo-mark svg { width: 24px; height: 24px; fill: white; }
.logo-text { line-height: 1.2; }
.logo-name {
  font-size: 20px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: .02em;
}
.logo-en {
  font-size: 10px;
  font-weight: 600;
  color: var(--text-light);
  letter-spacing: .1em;
  text-transform: uppercase;
}
.main-nav { flex: 1; display: flex; justify-content: center; }
.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav-item { position: relative; }
.nav-item > a {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 10px 14px;
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  border-radius: var(--radius);
  transition: all var(--transition);
  white-space: nowrap;
}
.nav-item > a:hover,
.nav-item.active > a {
  color: var(--accent);
  background: rgba(0,152,212,.07);
}
.nav-arrow {
  font-size: 10px;
  transition: transform var(--transition);
  opacity: .6;
}
.nav-item:hover .nav-arrow { transform: rotate(180deg); }

/* Dropdown */
.dropdown {
  position: absolute;
  top: 100%;
  left: 50%;
  min-width: 180px;
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 40px rgba(10,45,110,.16);
  border: 1px solid var(--border);
  opacity: 0;
  visibility: hidden;
  transform: translateX(-50%) translateY(-8px);
  transition: all var(--transition);
  z-index: 100;
  padding: 8px;
}
.nav-item:hover .dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}
.dropdown a {
  display: block;
  padding: 10px 16px;
  font-size: 14px;
  color: var(--text-secondary);
  border-radius: var(--radius);
  transition: all var(--transition);
  white-space: nowrap;
}
.dropdown a:hover {
  color: var(--accent);
  background: rgba(0,152,212,.07);
  padding-left: 20px;
}
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}
.btn-search {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: all var(--transition);
}
.btn-search:hover { background: var(--bg-light); color: var(--accent); }
.btn-contact {
  background: var(--primary);
  color: var(--white);
  padding: 9px 20px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 600;
  transition: all var(--transition);
}
.btn-contact:hover { background: var(--primary-light); }
.btn-lang {
  padding: 6px 14px;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 700;
  color: var(--primary);
  border: 1.5px solid var(--primary);
  transition: all var(--transition);
  letter-spacing: .05em;
  cursor: pointer;
  background: transparent;
}
.btn-lang:hover {
  background: var(--primary);
  color: var(--white);
}
.menu-toggle {
  display: none;
  width: 36px;
  height: 36px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  border-radius: var(--radius);
  transition: background var(--transition);
}
.menu-toggle:hover { background: var(--bg-light); }
.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 1px;
  transition: all var(--transition);
}
.menu-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle.open span:nth-child(2) { opacity: 0; }
.menu-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile nav */
.mobile-nav {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--white);
  z-index: 999;
  overflow-y: auto;
  padding: 16px 24px 40px;
  transform: translateX(100%);
  transition: transform var(--transition);
}
.mobile-nav.open {
  display: block;
  transform: translateX(0);
}
.mobile-nav-item { border-bottom: 1px solid var(--border); }
.mobile-nav-item > a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
  font-size: 16px;
  font-weight: 500;
  color: var(--text);
}
.mobile-sub {
  padding: 0 0 12px 16px;
  display: none;
}
.mobile-sub.open { display: block; }
.mobile-sub a {
  display: block;
  padding: 10px 0;
  font-size: 14px;
  color: var(--text-secondary);
  border-bottom: 1px dashed var(--border);
}
.mobile-sub a:last-child { border-bottom: none; }

/* ===== Footer ===== */
.site-footer {
  background: var(--primary-dark);
  color: rgba(255,255,255,.8);
}
.footer-main {
  padding: 64px 0 40px;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
}
.footer-brand .logo-name { color: white; }
.footer-brand .logo-en { color: rgba(255,255,255,.5); }
.footer-desc {
  font-size: 14px;
  color: rgba(255,255,255,.55);
  line-height: 1.8;
  margin-top: 16px;
  margin-bottom: 24px;
}
.footer-socials {
  display: flex;
  gap: 10px;
}
.social-link {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,.2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  transition: all var(--transition);
}
.social-link:hover { background: var(--accent); border-color: var(--accent); }
.footer-col-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(255,255,255,.1);
}
.footer-links { display: flex; flex-direction: column; gap: 10px; }
.footer-links a {
  font-size: 14px;
  color: rgba(255,255,255,.55);
  transition: color var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.footer-links a::before {
  content: '›';
  color: var(--accent);
  font-size: 16px;
  line-height: 1;
}
.footer-links a:hover { color: var(--white); }
.footer-contact-item {
  display: flex;
  gap: 10px;
  font-size: 14px;
  color: rgba(255,255,255,.55);
  margin-bottom: 12px;
  line-height: 1.5;
}
.footer-contact-item .icon {
  flex-shrink: 0;
  margin-top: 2px;
  color: var(--accent);
}
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08);
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 13px;
  color: rgba(255,255,255,.35);
}
.footer-bottom-links { display: flex; gap: 20px; }
.footer-bottom-links a { color: rgba(255,255,255,.35); transition: color var(--transition); }
.footer-bottom-links a:hover { color: rgba(255,255,255,.7); }

/* ===== Back to top ===== */
.back-to-top {
  position: fixed;
  right: 28px;
  bottom: 28px;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(10,45,110,.3);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: 500;
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { background: var(--accent); transform: translateY(-3px); }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .footer-main { grid-template-columns: 1fr 1fr; gap: 36px; }
}
@media (max-width: 768px) {
  :root { --nav-height: 60px; }
  .main-nav, .header-actions .btn-search, .header-actions .btn-contact { display: none; }
  .menu-toggle { display: flex; }
  .section { padding: 56px 0; }
  .section__header { margin-bottom: 36px; }
  .footer-main { grid-template-columns: 1fr; gap: 28px; padding: 40px 0 28px; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .container { padding: 0 16px; }
}