:root {
  --primary-color: #003366;
  --secondary-color: #FFCC00;
  --text-color-light: #ffffff;
  --text-color-dark: #333333;
  --header-offset: 110px; /* Desktop: header-top (60px) + main-nav (50px) */
}

@media (max-width: 768px) {
  :root {
    --header-offset: 108px; /* Mobile: header-top (60px) + mobile-nav-buttons (48px) */
  }
}

/* Base Styles */
body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding-top: var(--header-offset);
  line-height: 1.6;
  color: var(--text-color-dark);
  background-color: #f4f4f4;
  overflow-x: hidden; /* Prevent body overflow on mobile */
}

/* Shared Container Styles */
.header-container, .nav-container, .footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 10px 18px;
  border-radius: 5px;
  text-decoration: none;
  font-weight: bold;
  text-align: center;
  cursor: pointer;
  transition: background-color 0.3s ease, transform 0.2s ease;
  white-space: nowrap;
  box-sizing: border-box;
}

.btn-primary {
  background-color: var(--secondary-color);
  color: var(--primary-color);
  border: 1px solid var(--secondary-color);
}

.btn-primary:hover {
  background-color: #e6b800;
  transform: translateY(-2px);
}

.btn-secondary {
  background-color: var(--primary-color);
  color: var(--secondary-color);
  border: 1px solid var(--secondary-color);
}

.btn-secondary:hover {
  background-color: #002244;
  transform: translateY(-2px);
}

/* Header Styles */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  background-color: var(--primary-color); /* Fallback, specific sections will override */
}

.site-header .header-top {
  background-color: var(--primary-color); /* Deep Blue */
  min-height: 60px;
  display: flex;
  align-items: center;
}

.site-header .header-top .header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  padding: 0 20px; /* Ensure spacing from edges */
}

.site-header .logo {
  font-size: 28px;
  font-weight: bold;
  color: var(--secondary-color);
  text-decoration: none;
  padding: 5px 0;
  white-space: nowrap;
}

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

.site-header .main-nav {
  background-color: #004488; /* Slightly lighter blue for contrast */
  min-height: 50px;
  display: flex; /* Desktop default */
  align-items: center;
}

.site-header .main-nav .nav-container {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  padding: 0 20px;
}

.site-header .nav-link {
  color: var(--text-color-light);
  text-decoration: none;
  padding: 10px 15px;
  display: block;
  transition: background-color 0.3s ease, color 0.3s ease;
  white-space: nowrap;
}

.site-header .nav-link:hover, .site-header .nav-link.active {
  background-color: var(--secondary-color);
  color: var(--primary-color);
  border-radius: 3px;
}

/* Hamburger Menu (Desktop Hidden) */
.hamburger-menu {
  display: none; /* Hidden on desktop */
  background: none;
  border: none;
  cursor: pointer;
  padding: 10px;
  z-index: 1001;
}

.hamburger-icon {
  display: block;
  width: 25px;
  height: 3px;
  background-color: var(--secondary-color);
  position: relative;
  transition: background-color 0.3s ease;
}

.hamburger-icon::before, .hamburger-icon::after {
  content: '';
  display: block;
  width: 100%;
  height: 3px;
  background-color: var(--secondary-color);
  position: absolute;
  transition: transform 0.3s ease, top 0.3s ease;
}

.hamburger-icon::before {
  top: -8px;
}

.hamburger-icon::after {
  top: 8px;
}

.hamburger-menu.active .hamburger-icon {
  background-color: transparent;
}

.hamburger-menu.active .hamburger-icon::before {
  transform: rotate(45deg);
  top: 0;
}

.hamburger-menu.active .hamburger-icon::after {
  transform: rotate(-45deg);
  top: 0;
}

/* Mobile Nav Buttons (Desktop Hidden) */
.mobile-nav-buttons {
  display: none; /* Hidden on desktop */
}

.mobile-menu-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.7);
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.mobile-menu-overlay.active {
  opacity: 1;
  visibility: visible;
}

/* Footer Styles */
.site-footer {
  background-color: var(--primary-color);
  color: var(--text-color-light);
  padding: 40px 0 20px;
  font-size: 14px;
}

.site-footer .footer-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 20px;
}

.site-footer .footer-col {
  flex: 1 1 200px; /* Allows columns to wrap */
  margin-bottom: 20px;
}

.site-footer h3 {
  color: var(--secondary-color);
  font-size: 18px;
  margin-bottom: 15px;
}

.site-footer p {
  margin-bottom: 10px;
}

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

.site-footer .footer-nav li {
  margin-bottom: 8px;
}

.site-footer .footer-nav a {
  color: var(--text-color-light);
  text-decoration: none;
  transition: color 0.3s ease;
}

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

.site-footer .footer-bottom {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  margin-top: 20px;
}

/* Responsive Styles */
@media (max-width: 768px) {
  .header-container, .nav-container, .footer-container {
    padding: 0 15px;
    max-width: none; /* Ensure full width on mobile */
    width: 100%;
  }

  .site-header .header-top .header-container {
    justify-content: space-between;
  }

  .hamburger-menu {
    display: block; /* Show hamburger on mobile */
    order: 1;
  }

  .site-header .logo {
    order: 2;
    flex: 1;
    display: flex;
    justify-content: center;
    padding: 5px 0;
  }

  .site-header .desktop-nav-buttons {
    display: none; /* Hide desktop buttons on mobile */
  }

  .site-header .main-nav {
    display: none; /* Hidden by default on mobile */
    flex-direction: column;
    position: fixed;
    top: var(--header-offset);
    left: 0;
    width: 280px;
    height: calc(100% - var(--header-offset));
    background-color: var(--primary-color);
    transform: translateX(-100%); /* Off-screen by default */
    transition: transform 0.3s ease;
    overflow-y: auto;
    z-index: 1000;
    box-shadow: 2px 0 5px rgba(0, 0, 0, 0.3);
  }

  .site-header .main-nav.active {
    display: flex; /* Show when active */
    transform: translateX(0); /* Slide in */
  }

  .site-header .main-nav .nav-container {
    flex-direction: column;
    align-items: flex-start;
    padding: 10px 0;
  }

  .site-header .nav-link {
    width: 100%;
    padding: 12px 20px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  }

  .site-header .nav-link:last-child {
    border-bottom: none;
  }

  .mobile-nav-buttons {
    display: flex !important;
    width: 100%;
    max-width: 100%;
    box-sizing: border-box;
    padding: 10px 15px;
    overflow: hidden;
    gap: 10px;
    flex-wrap: nowrap;
    background-color: var(--primary-color); /* Match header top */
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    justify-content: center;
    align-items: center;
    min-height: 48px; /* Approx height for 2 buttons */
  }

  .mobile-nav-buttons .btn {
    flex: 1;
    min-width: 0;
    max-width: calc(50% - 5px); /* Account for gap */
    box-sizing: border-box;
    padding: 8px 12px;
    font-size: 13px;
    white-space: normal;
    word-wrap: break-word;
    overflow-wrap: break-word;
    height: auto; /* Allow text to wrap */
  }

  .site-footer .footer-container {
    flex-direction: column;
    text-align: center;
  }

  .site-footer .footer-col {
    flex: 1 1 100%;
  }

  .site-footer h3 {
    margin-top: 20px;
  }

  /* Mobile content overflow protection */
  .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;
  }
}