:root {
  --site-header-bg: #113B7A;
  --site-header-top-bg: #081B36;
  --site-nav-bg: #1D5FD1;
  --site-btn-bg: linear-gradient(180deg, #2B73F6 0%, #1144A6 100%);
  --site-btn-hover-bg: linear-gradient(180deg, #4FA8FF 0%, #2B73F6 100%);
  --site-text-main: #F3F8FF;
  --site-text-secondary: #AFC4E8;
  --site-border: #244D84;
  --site-divider: #1B3357;
  --site-footer-bg: #08162B;
  --header-offset: 122px;
}

body {
  padding-top: var(--header-offset);
  margin: 0;
  font-family: 'Segoe UI', Arial, sans-serif;
  background: #0A1428;
  color: var(--site-text-main);
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: var(--site-header-bg);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.header-top {
  background: var(--site-header-top-bg);
  border-bottom: 1px solid var(--site-border);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 24px;
  gap: 20px;
}

.logo {
  display: inline-block;
  font-size: 28px;
  font-weight: 800;
  color: var(--site-text-main);
  text-decoration: none;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.desktop-nav-buttons {
  display: flex;
  gap: 12px;
}

.btn {
  display: inline-block;
  padding: 8px 20px;
  border-radius: 24px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  text-align: center;
  transition: all 0.3s ease;
  color: var(--site-text-main);
  white-space: nowrap;
}

.btn-register {
  background: var(--site-btn-bg);
  box-shadow: 0 0 10px rgba(79, 168, 255, 0.3);
}

.btn-register:hover {
  background: var(--site-btn-hover-bg);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(79, 168, 255, 0.5);
}

.btn-login {
  background: transparent;
  border: 2px solid var(--site-border);
}

.btn-login:hover {
  background: rgba(79, 168, 255, 0.15);
  border-color: var(--site-border);
}

.main-nav {
  display: flex;
  background: var(--site-nav-bg);
  border-bottom: 1px solid var(--site-border);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  padding: 8px 20px;
  gap: 4px;
  width: 100%;
  flex-wrap: wrap;
  overflow: hidden;
}

.nav-link {
  display: block;
  padding: 8px 14px;
  font-size: 14px;
  font-weight: 600;
  color: var(--site-text-main);
  text-decoration: none;
  border-radius: 6px;
  white-space: nowrap;
  position: relative;
}

.nav-link:hover {
  color: var(--site-text-main);
  background: rgba(255, 255, 255, 0.1);
}

.nav-link::after {
  content: '';
  display: none;
}

.hamburger-menu {
  display: none;
}

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

.mobile-nav-buttons {
  display: none;
}

.site-footer {
  background: var(--site-footer-bg);
  border-top: 3px solid var(--site-border);
  padding: 0;
  width: 100%;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr;
  gap: 30px;
  padding: 40px 24px 30px;
}

.footer-brand {
  padding-right: 20px;
}

.footer-logo {
  display: block;
  font-size: 24px;
  font-weight: 800;
  color: var(--site-text-main);
  text-decoration: none;
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.footer-desc {
  font-size: 14px;
  line-height: 1.6;
  color: var(--site-text-secondary);
  margin-bottom: 16px;
}

.footer-heading {
  font-size: 16px;
  font-weight: 700;
  color: var(--site-text-main);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--site-border);
}

.footer-nav {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-nav li {
  margin-bottom: 10px;
}

.footer-nav a {
  color: var(--site-text-secondary);
  text-decoration: none;
  font-size: 13px;
  transition: color 0.2s;
}

.footer-nav a:hover {
  color: var(--site-text-main);
}

.footer-contact-text {
  font-size: 14px;
  color: var(--site-text-secondary);
  line-height: 1.6;
  margin-bottom: 10px;
}

.footer-bottom {
  border-top: 1px solid var(--site-divider);
  padding: 15px 20px;
  text-align: center;
}

.copyright {
  font-size: 13px;
  color: var(--site-text-secondary);
  margin: 0;
}

@media (max-width: 768px) {
  :root {
    --header-offset: 110px;
  }

  .site-header {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
  }

  .header-container {
    width: 100%;
    max-width: none;
    padding: 10px 15px;
    gap: 10px;
  }

  .nav-container {
    width: 100%;
    max-width: none;
    padding: 15px;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    gap: 10px;
  }

  .main-nav {
    display: none;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    width: 280px;
    height: 100vh;
    background: #113B7A;
    z-index: 1001;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    border-right: 1px solid var(--site-border);
    overflow-y: auto;
  }

  .main-nav.active {
    display: block;
    transform: translateX(0);
  }

  .nav-link {
    display: block;
    padding: 8px 16px;
  }

  .hamburger-menu {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 44px;
    min-width: 44px;
    height: 44px;
    cursor: pointer;
    background: transparent;
    border: 1px solid var(--site-border);
    border-radius: 8px;
    padding: 0;
    cursor: pointer;
    z-index: 1002;
    order: -1;
    flex: 0 0 auto;
  }

  .hamburger-menu span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--site-text-main);
    margin: 3px auto;
    transition: all 0.3s ease;
    border-radius: 2px;
  }

  .hamburger-menu.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .hamburger-menu.active span:nth-child(2) {
    opacity: 0;
  }

  .hamburger-menu.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
  }

  .mobile-menu-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
    opacity: 0;
    transition: opacity 0.3s ease;
  }

  .mobile-menu-overlay.active {
    display: block;
    opacity: 1;
  }

  .mobile-nav-buttons {
    display: flex;
    gap: 10px;
    justify-content: center;
    padding: 8px 16px;
    background: #0B1D3D;
    border-bottom: 1px solid var(--site-border);
    width: 100%;
    box-sizing: border-box;
  }

  .mobile-nav-buttons .btn {
    flex: 1;
    max-width: 200px;
    padding: 8px 16px;
    font-size: 13px;
  }

  .header-top {
    order: 1;
  }

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

  .mobile-menu-overlay.active {
    display: block;
    opacity: 1;
  }

  .site-header {
    display: flex;
    flex-wrap: wrap;
  }

  .site-header .header-top {
    order: 1;
    width: 100%;
  }

  .site-header .mobile-nav-buttons {
    order: 2;
    width: 100%;
  }

  .site-header .main-nav {
    order: 3;
  }

  .hamburger-menu {
    order: -1;
  }

  .logo {
    flex: 1;
    text-align: center;
    font-size: 20px;
    order: 0;
  }

  .header-container .desktop-nav-buttons {
    display: none;
  }

  .footer-container {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 28px 20px;
  }

  .footer-brand {
    padding-right: 0;
  }

  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }

  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }

  body {
    overflow-x: hidden;
  }
}
/* 移动端内容区防溢出（系统追加，请勿删除） */
@media (max-width: 768px) {
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
  body {
    overflow-x: hidden;
  }
}
/* 内容保护（系统追加，请勿删除） */
body {
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}
input, textarea, select, [contenteditable="true"] {
  -webkit-user-select: text;
  -moz-user-select: text;
  user-select: text;
}