body {
  margin: 0;
  font-family: Arial, sans-serif;
  line-height: 1.6;
  color: #1F2D3D; /* Text Main */
  background-color: #F4F7FB; /* Background */
  padding-top: var(--header-offset); /* Fixed header spacing */
  overflow-x: hidden; /* Prevent horizontal scroll from body */
}

a {
  text-decoration: none;
  color: #2F6BFF; /* Main color for links */
}

a:hover {
  text-decoration: underline;
}

/* Header Offset - Mandatory */
:root {
  --header-offset: 122px; /* Desktop: header-top (68px) + main-nav (52px) + 2px buffer */
}

/* Site Header - Fixed & Suspended */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  background-color: #FFFFFF; /* Ensures solid background */
  box-sizing: border-box;
  overflow-x: hidden; /* Prevent header content overflow */
}

/* Header Top Section - Desktop */
.header-top {
  box-sizing: border-box;
  min-height: 68px;
  height: 68px; /* Fixed height for desktop */
  display: flex;
  align-items: center;
  overflow: hidden;
  background-color: #2F6BFF; /* Main color for header-top */
  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 20px; /* Padding for logo and buttons */
}

.logo {
  font-size: 28px;
  font-weight: bold;
  color: #FFFFFF; /* White for logo text on main color background */
  display: block;
  text-decoration: none;
}

.logo img {
  display: block;
  max-height: 60px; /* Max height for desktop logo image */
  height: auto;
  width: auto;
  max-width: 280px;
  object-fit: contain;
}

.desktop-nav-buttons {
  display: flex; /* Visible on desktop */
  gap: 12px;
  align-items: center;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 10px 20px;
  border-radius: 25px;
  font-weight: bold;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: all 0.3s ease;
  color: #FFFFFF; /* White text for buttons */
  background: linear-gradient(180deg, #4A8BFF 0%, #2F6BFF 100%); /* Button gradient */
  border: none;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

.btn:hover {
  opacity: 0.9;
  box-shadow: 0 6px 15px rgba(0, 0, 0, 0.3);
  text-decoration: none; /* Ensure no underline on hover */
}

/* Mobile Nav Buttons - Hidden on Desktop */
.mobile-nav-buttons {
  box-sizing: border-box;
  display: none; /* Hidden by default on desktop */
  min-height: 48px;
  width: 100%;
  background-color: #6FA3FF; /* Accent color for mobile button bar */
  padding: 10px 20px;
  justify-content: center;
  align-items: center;
  gap: 10px;
  overflow: hidden;
}

/* Main Navigation - Desktop */
.main-nav {
  box-sizing: border-box;
  min-height: 52px;
  height: 52px; /* Fixed height for desktop */
  display: flex; /* Visible on desktop */
  align-items: center;
  overflow: hidden;
  background-color: #F4F7FB; /* Background color for main nav */
  width: 100%;
}

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

.nav-link {
  color: #1F2D3D; /* Text Main */
  font-weight: bold;
  padding: 0 15px;
  transition: color 0.3s ease;
  white-space: nowrap;
}

.nav-link:hover {
  color: #2F6BFF; /* Main color on hover */
  text-decoration: none;
}

/* Hamburger Menu - Hidden on Desktop */
.hamburger-menu {
  display: none; /* Hidden by default on desktop */
  flex-direction: column;
  justify-content: space-around;
  width: 30px;
  height: 25px;
  cursor: pointer;
  z-index: 1001; /* Above header */
}

.hamburger-menu span {
  display: block;
  width: 100%;
  height: 3px;
  background-color: #FFFFFF; /* White for hamburger on main color background */
  border-radius: 3px;
  transition: all 0.3s ease-in-out;
}

.hamburger-menu.active span:nth-child(1) {
  transform: translateY(11px) rotate(45deg);
}

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

.hamburger-menu.active span:nth-child(3) {
  transform: translateY(-11px) rotate(-45deg);
}

/* Overlay - Hidden by default */
.overlay {
  display: none; 
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 998; /* Below mobile menu, above content */
  transition: opacity 0.3s ease;
  opacity: 0;
}

.overlay.active {
  display: block;
  opacity: 1;
}

/* Footer Styles */
.site-footer {
  background-color: #1F2D3D; /* Dark background for footer */
  color: #F4F7FB; /* Light text for footer */
  padding: 40px 20px 20px;
  font-size: 14px;
  box-sizing: border-box;
}

.site-footer a {
  color: #6FA3FF; /* Accent color for footer links */
  text-decoration: none;
}

.site-footer a:hover {
  text-decoration: underline;
}

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

.footer-col h3 {
  color: #FFFFFF;
  font-size: 16px;
  margin-bottom: 15px;
}

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

.footer-description {
  margin-bottom: 15px;
  line-height: 1.8;
  color: #F4F7FB;
}

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

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

.footer-bottom {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: #D6E2FF; /* Border color for copyright text */
}

/* Mobile Responsive Styles */
@media (max-width: 768px) {
  body {
    padding-top: var(--header-offset);
    overflow-x: hidden; /* Ensure body prevents horizontal scroll */
  }

  :root {
    --header-offset: 110px; /* Mobile: header-top (60px) + mobile-nav-buttons (48px) + 2px buffer */
  }

  /* Header Top Section - Mobile */
  .header-top {
    min-height: 60px !important;
    height: 60px !important; /* Fixed height for mobile */
    padding: 0 15px; /* Adjust padding for mobile */
    justify-content: space-between; /* Space out hamburger and logo */
  }

  .header-container {
    width: 100%;
    max-width: none; /* Full width for mobile container */
    padding: 0; /* Remove container padding as header-top has it */
    position: relative; /* For absolute logo positioning if needed */
  }

  .logo {
    flex: 1 !important; /* Allow logo to take flexible space */
    display: flex !important;
    justify-content: center !important; /* Center logo horizontally */
    align-items: center !important;
    position: absolute; /* Absolute positioning for logo centering */
    left: 50%;
    transform: translateX(-50%);
    max-width: calc(100% - 100px); /* Ensure logo doesn't overlap hamburger/buttons */
  }
  
  .logo img {
    max-height: 56px !important; /* Max height for mobile logo image */
    max-width: 100%; /* Ensure image scales within logo container */
  }

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

  .hamburger-menu {
    display: flex; /* Show hamburger on mobile */
    order: -1; /* Place hamburger on the left */
    margin-right: auto; /* Push logo and buttons to the right */
    position: relative;
    z-index: 1002; /* Ensure hamburger is clickable */
  }

  /* Mobile Nav Buttons - Show on Mobile */
  .mobile-nav-buttons {
    display: flex !important; /* Show mobile buttons */
    min-height: 48px;
    width: 100%;
    max-width: 100%;
    box-sizing: border-box;
    padding: 8px 15px;
    overflow: hidden;
    gap: 10px;
    flex-wrap: nowrap; /* Ensure buttons stay in one line */
  }

  .mobile-nav-buttons .btn {
    flex: 1;
    min-width: 0;
    max-width: calc(50% - 5px);
    box-sizing: border-box;
    padding: 8px 12px;
    font-size: 13px;
    white-space: normal;
    word-wrap: break-word;
    overflow-wrap: break-word;
  }

  /* Main Navigation - Mobile */
  .main-nav {
    display: none; /* Hidden by default on mobile */
    flex-direction: column;
    position: fixed;
    top: var(--header-offset); /* Position below fixed header */
    left: 0;
    width: 280px; /* Width of the mobile menu */
    height: calc(100% - var(--header-offset)); /* Full height below header */
    background-color: #FFFFFF; /* White background for mobile menu */
    box-shadow: 2px 0 5px rgba(0, 0, 0, 0.2);
    transform: translateX(-100%); /* Off-screen by default */
    transition: transform 0.3s ease;
    z-index: 1001; /* Above overlay */
    overflow-y: auto; /* Allow scrolling for long menus */
    box-sizing: border-box;
  }

  .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: 20px 15px; /* Padding inside mobile menu */
    height: auto; /* Allow content to define height */
    max-width: none; /* Full width for mobile container */
  }

  .nav-link {
    width: 100%;
    padding: 10px 0;
    border-bottom: 1px solid #F4F7FB; /* Light border for menu items */
    text-align: left;
  }

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

  /* Footer - Mobile */
  .footer-top-grid {
    grid-template-columns: 1fr; /* Single column layout for mobile */
  }

  .footer-col {
    text-align: center; /* Center footer content */
  }

  .footer-col 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%;
  }
}

/* Prevent body scroll when mobile menu is open */
body.no-scroll {
  overflow: 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;
}