:root {
  --primary-color: #2F6BFF;
  --secondary-color: #6FA3FF;
  --button-gradient: linear-gradient(180deg, #4A8BFF 0%, #2F6BFF 100%);
  --card-bg: #FFFFFF;
  --body-bg: #F4F7FB;
  --text-main: #1F2D3D;
  --text-black: #000000;
  --border-color: #D6E2FF;
  --glow-color: #A5C4FF;
  --header-offset: 122px; /* Desktop: 68px (header-top) + 52px (main-nav) */
}

body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding-top: var(--header-offset);
  background-color: var(--body-bg);
  color: var(--text-main);
  overflow-x: hidden; /* Global overflow-x for body */
}

/* Site Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  background-color: var(--card-bg); /* Default background, individual sections will override */
}

/* Header Top Section */
.header-top {
  box-sizing: border-box;
  height: 68px; /* Desktop fixed height */
  display: flex;
  align-items: center;
  overflow: hidden;
  background-color: #1A3A70; /* Darker blue for header top */
  color: #FFFFFF;
  width: 100%;
}

.header-container {
  box-sizing: border-box;
  width: 100%;
  height: 100%;
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 30px; /* Padding for logo and buttons */
}

.logo {
  font-size: 28px;
  font-weight: bold;
  color: #FFFFFF;
  text-decoration: none;
  display: block;
}

.logo img { /* For potential image logo */
  display: block;
  max-height: 60px; /* Desktop max height */
  height: auto;
  width: auto;
  max-width: 280px;
  object-fit: contain;
}

/* Desktop Navigation Buttons */
.desktop-nav-buttons {
  display: flex;
  gap: 12px;
  align-items: center;
}

.btn {
  padding: 10px 20px;
  border-radius: 25px;
  text-decoration: none;
  font-weight: bold;
  font-size: 15px;
  white-space: nowrap;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: center;
  box-sizing: border-box;
  color: #FFFFFF; /* Default button text color */
}

.btn-login {
  background: var(--button-gradient);
  border: 1px solid var(--primary-color);
}
.btn-login:hover {
  opacity: 0.9;
  box-shadow: 0 0 10px var(--glow-color);
}

.btn-register {
  background: var(--button-gradient);
  border: 1px solid var(--primary-color);
}
.btn-register:hover {
  opacity: 0.9;
  box-shadow: 0 0 10px var(--glow-color);
}

/* Mobile Navigation Buttons (hidden by default on desktop) */
.mobile-nav-buttons {
  box-sizing: border-box;
  display: none; /* Hidden on desktop */
  min-height: 48px; /* Fixed height for mobile */
  background-color: var(--body-bg); /* Subtle background */
  width: 100%;
  padding: 8px 15px; /* Adjust padding for mobile */
  gap: 10px;
  align-items: center;
  justify-content: center; /* Center buttons horizontally */
  box-shadow: 0 1px 5px rgba(0, 0, 0, 0.05);
}

/* Main Navigation */
.main-nav {
  box-sizing: border-box;
  height: 52px; /* Desktop fixed height */
  display: flex; /* Desktop default: flex */
  align-items: center;
  overflow: hidden;
  background-color: var(--secondary-color); /* Lighter blue for main nav */
  width: 100%;
  color: var(--text-main);
  position: static; /* Desktop default: static */
}

.nav-container {
  box-sizing: border-box;
  height: 100%;
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: row;
  justify-content: center; /* Center nav links */
  align-items: center;
  padding: 0 20px;
}

.nav-link {
  padding: 0 15px;
  color: var(--text-main);
  text-decoration: none;
  font-weight: bold;
  font-size: 16px;
  white-space: nowrap;
  transition: color 0.3s ease;
  height: 100%; /* Make links fill height for better click area */
  display: flex;
  align-items: center;
}

.nav-link:hover {
  color: var(--primary-color);
}

/* Hamburger Menu (hidden on desktop) */
.hamburger-menu {
  display: none; /* Hidden on desktop */
  width: 30px;
  height: 24px;
  position: relative;
  cursor: pointer;
  z-index: 1001; /* Above header */
  flex-direction: column;
  justify-content: space-between;
  order: 1; /* For mobile layout */
}

.hamburger-menu span {
  display: block;
  width: 100%;
  height: 3px;
  background-color: #FFFFFF;
  transition: all 0.3s ease;
}

/* Overlay (hidden by default) */
.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;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.overlay.active {
  opacity: 1;
  visibility: visible;
}

/* Footer */
.site-footer {
  background-color: #1A3A70; /* Darker blue for footer */
  color: #FFFFFF;
  padding: 40px 20px 20px;
  font-size: 14px;
}

.site-footer a {
  color: #FFFFFF;
  text-decoration: none;
  transition: color 0.3s ease;
}

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

.footer-top-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  max-width: 1200px;
  margin: 0 auto 30px;
}

.footer-col h3 {
  font-size: 18px;
  margin-bottom: 15px;
  color: #FFFFFF;
}

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

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

.footer-logo {
  font-size: 24px;
  font-weight: bold;
  margin-bottom: 15px;
  display: block;
}

.footer-description {
  line-height: 1.6;
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.footer-bottom {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  max-width: 1200px;
  margin: 0 auto;
}

.footer-slot-anchor-inner { /* Ensures anchors are visible */
  min-height: 1px;
}

/* --- Mobile Styles --- */
@media (max-width: 768px) {
  :root {
    --header-offset: 110px; /* Mobile: 60px (header-top) + 48px (mobile-nav-buttons) */
  }

  body {
    padding-top: var(--header-offset);
    overflow-x: hidden; /* Prevent body horizontal scroll */
  }

  /* Mobile Content Overflow Protection */
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }

  .header-top {
    height: 60px !important; /* Mobile fixed height */
    padding: 0 15px;
    justify-content: space-between; /* Space out hamburger and logo */
  }

  .header-container {
    width: 100%;
    max-width: none; /* No max-width on mobile */
    padding: 0; /* Remove horizontal padding, handled by header-top */
    justify-content: center; /* Default for logo, will be overridden by flex logic */
    position: relative; /* For absolute positioning of logo if needed */
  }

  .logo {
    flex: 1 !important;
    display: flex !important;
    justify-content: center !important; /* Center logo */
    align-items: center !important;
    font-size: 24px; /* Adjust font size for mobile */
    order: 2; /* Place logo in middle */
  }

  .logo img {
    max-height: 56px !important; /* Mobile max height */
  }

  .hamburger-menu {
    display: flex;
    order: 1; /* Place hamburger menu first */
  }
  .hamburger-menu.active span:nth-child(1) {
    transform: translateY(10px) rotate(45deg);
  }
  .hamburger-menu.active span:nth-child(2) {
    opacity: 0;
  }
  .hamburger-menu.active span:nth-child(3) {
    transform: translateY(-10px) rotate(-45deg);
  }

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

  .mobile-nav-buttons {
    display: flex !important; /* Show mobile buttons */
    justify-content: center;
    align-items: center;
    width: 100%;
    max-width: 100%; /* Ensure no overflow */
    box-sizing: border-box;
    padding: 8px 15px; /* Mobile padding */
    overflow: hidden; /* Prevent buttons from overflowing */
    gap: 10px;
    flex-wrap: nowrap; /* Keep buttons on one line */
    background-color: var(--body-bg); /* Use body background for this strip */
  }

  .mobile-nav-buttons .btn {
    flex: 1;
    min-width: 0; /* Allow shrinking */
    max-width: calc(50% - 5px); /* Max width for two buttons with gap */
    padding: 8px 12px; /* Smaller padding */
    font-size: 13px; /* Smaller font size */
    white-space: normal; /* Allow text wrapping */
    word-wrap: break-word;
    overflow-wrap: break-word;
  }

  .main-nav {
    display: none; /* Hidden by default on mobile */
    position: fixed; /* Fixed position for mobile menu */
    top: var(--header-offset); /* Position below fixed header and mobile buttons */
    left: 0;
    width: 280px; /* Width of the mobile menu */
    height: calc(100% - var(--header-offset)); /* Full height below header */
    background-color: var(--card-bg); /* Use card background for slide-out menu */
    flex-direction: column; /* Vertical layout for menu items */
    align-items: flex-start;
    padding: 20px;
    box-shadow: 2px 0 10px rgba(0, 0, 0, 0.2);
    transform: translateX(-100%); /* Slide out from left */
    transition: transform 0.3s ease;
    z-index: 1000; /* Same as header or slightly above */
    overflow-y: auto; /* Allow scrolling for many menu items */
  }

  .main-nav.active {
    display: flex; /* Show menu when active */
    transform: translateX(0); /* Slide into view */
  }

  .nav-container {
    flex-direction: column;
    align-items: flex-start;
    padding: 0;
    width: 100%;
    max-width: none; /* No max-width on mobile */
  }

  .nav-link {
    width: 100%;
    padding: 12px 0;
    border-bottom: 1px solid #eee;
    font-size: 16px;
    justify-content: flex-start;
  }
  .nav-link:last-child {
    border-bottom: none;
  }

  .footer-top-grid {
    grid-template-columns: 1fr; /* Single column on mobile */
  }

  .footer-col {
    margin-bottom: 20px;
  }
}
/* 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;
}