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

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

/* Base styles for anchors/buttons */
a {
  text-decoration: none;
  color: var(--primary-color);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  border-radius: 8px;
  background: var(--button-gradient);
  color: var(--card-bg); /* White text on button */
  font-weight: bold;
  font-size: 15px;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
  white-space: nowrap;
  text-decoration: none; /* Remove underline for buttons */
}

.btn:hover {
  opacity: 0.9;
  transform: translateY(-2px);
  box-shadow: 0 6px 15px rgba(0, 0, 0, 0.3), 0 0 15px var(--glow-color);
}

/* Site Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  background-color: transparent; /* Handled by child elements */
}

.header-top {
  box-sizing: border-box;
  min-height: 68px;
  height: 68px;
  display: flex;
  align-items: center;
  overflow: hidden;
  background-color: var(--primary-color); /* Main color for header-top */
  width: 100%;
  color: var(--card-bg); /* White text for header-top */
}

.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-left: 20px; /* Adjusted padding */
  padding-right: 20px; /* Adjusted padding */
}

.logo {
  font-size: 28px;
  font-weight: bold;
  color: var(--card-bg); /* White color for logo text */
  text-decoration: none;
  display: flex; /* For potential image logo alignment */
  align-items: center;
  height: 100%;
}

.logo img {
  display: block;
  max-height: 60px;
  height: auto;
  width: auto;
  max-width: 280px;
  object-fit: contain;
}

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

/* Mobile nav buttons (hidden on desktop) */
.mobile-nav-buttons {
  box-sizing: border-box;
  display: none; /* Hidden by default on desktop */
  min-height: 48px; /* Fixed height for mobile */
  background-color: var(--card-bg); /* White background for mobile buttons */
  box-shadow: 0 2px 5px rgba(0,0,0,0.05); /* Subtle shadow */
}

.main-nav {
  box-sizing: border-box;
  min-height: 52px;
  height: 52px;
  display: flex; /* Desktop: display flex */
  align-items: center;
  overflow: hidden;
  background-color: var(--card-bg); /* White background for main-nav */
  width: 100%;
  border-top: 1px solid var(--border-color); /* Subtle border to separate from header-top */
}

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

.nav-link {
  color: var(--text-main); /* Dark text for nav links */
  padding: 0 15px;
  font-weight: 600;
  font-size: 16px;
  transition: color 0.3s ease;
  height: 100%;
  display: flex;
  align-items: center;
  white-space: nowrap;
}

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

/* Hamburger Menu (mobile only) */
.hamburger-menu {
  display: none; /* Hidden on desktop */
  width: 30px;
  height: 24px;
  position: relative;
  cursor: pointer;
  z-index: 1001; /* Higher than header-top */
  flex-shrink: 0;
  margin-right: 15px;
}

.hamburger-menu span {
  display: block;
  height: 3px;
  width: 100%;
  background-color: var(--card-bg); /* White bars */
  position: absolute;
  left: 0;
  transition: all 0.3s ease;
}

.hamburger-menu span:nth-child(1) { top: 0; }
.hamburger-menu span:nth-child(2) { top: 50%; transform: translateY(-50%); }
.hamburger-menu span:nth-child(3) { bottom: 0; }

.hamburger-menu.active span:nth-child(1) { top: 50%; transform: translateY(-50%) rotate(45deg); }
.hamburger-menu.active span:nth-child(2) { opacity: 0; }
.hamburger-menu.active span:nth-child(3) { bottom: 50%; transform: translateY(50%) rotate(-45deg); }

/* Overlay for mobile menu */
.overlay {
  display: none; /* Hidden by default */
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 999; /* Below menu, above content */
  transition: opacity 0.3s ease;
  opacity: 0;
}

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

/* Site Footer */
.site-footer {
  background-color: var(--text-main); /* Dark background for footer */
  color: var(--card-bg); /* White text for footer */
  padding: 40px 20px 20px;
  font-size: 14px;
}

.site-footer a {
  color: var(--accent-color); /* Accent color for footer links */
  text-decoration: none;
  transition: color 0.3s ease;
}

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

.footer-top-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  max-width: 1200px;
  margin: 0 auto 30px;
  padding-bottom: 30px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-col h3 {
  color: var(--card-bg);
  font-size: 16px;
  margin-bottom: 15px;
  text-transform: uppercase;
}

.footer-col p {
  line-height: 1.6;
  margin-bottom: 15px;
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.footer-logo {
  font-size: 24px;
  font-weight: bold;
  color: var(--card-bg);
  margin-bottom: 15px;
  display: block;
}

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

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

.footer-bottom {
  text-align: center;
  max-width: 1200px;
  margin: 0 auto;
  padding-top: 20px;
  color: rgba(255, 255, 255, 0.7);
}

.footer-bottom p {
  margin: 0;
}

/* Mobile specific styles */
@media (max-width: 768px) {
  :root {
    --header-offset: 110px; /* Mobile: header-top (60px) + mobile-nav-buttons (48px) + 2px buffer */
  }

  body {
    padding-top: var(--header-offset);
  }

  /* Header adjustments */
  .header-top {
    min-height: 60px !important;
    height: 60px !important;
    justify-content: space-between; /* For hamburger and logo */
  }

  .header-container {
    width: 100%;
    max-width: none; /* No max-width on mobile */
    padding-left: 15px;
    padding-right: 15px;
    position: relative; /* For absolute positioning of logo */
  }

  .logo {
    position: absolute !important;
    left: 50% !important;
    transform: translateX(-50%) !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    max-width: calc(100% - 100px); /* Ensure space for hamburger */
    height: 100%; /* To ensure vertical centering if logo is image */
  }

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

  .hamburger-menu {
    display: block; /* Show hamburger menu */
    order: -1; /* Place it first */
    position: relative; /* Ensure it stays in flow or has z-index */
    z-index: 2; /* Ensure it's above logo if they overlap */
    margin-right: 0; /* Remove desktop margin */
  }

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

  .mobile-nav-buttons {
    display: flex !important; /* Show mobile buttons */
    min-height: 48px;
    align-items: center;
    justify-content: center; /* Center buttons horizontally */
    width: 100%;
    max-width: 100%;
    box-sizing: border-box;
    padding-left: 15px;
    padding-right: 15px;
    overflow: hidden; /* Prevent overflow */
    gap: 10px;
    flex-wrap: nowrap;
    background-color: var(--card-bg); /* White background for mobile buttons */
    box-shadow: 0 2px 5px rgba(0,0,0,0.05); /* Subtle shadow */
  }

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

  .main-nav {
    display: none; /* Hidden by default on mobile */
    flex-direction: column;
    position: fixed;
    top: var(--header-offset); /* Position below header-top and mobile-nav-buttons */
    left: 0;
    width: 80%; /* Menu width */
    max-width: 300px; /* Max width for menu */
    height: calc(100% - var(--header-offset)); /* Fill remaining height */
    background-color: var(--card-bg); /* White background for mobile menu */
    box-shadow: 2px 0 10px rgba(0, 0, 0, 0.2);
    transform: translateX(-100%); /* Slide out of view */
    transition: transform 0.3s ease;
    z-index: 1001; /* Higher than overlay */
    overflow-y: auto; /* Scroll for long menus */
    align-items: flex-start; /* Align links to the left */
    border-top: none; /* Remove border from desktop version */
    padding: 20px 0; /* Add padding to top/bottom */
  }

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

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

  .nav-link {
    width: 100%;
    padding: 12px 20px;
    border-bottom: 1px solid var(--bg-color); /* Separator */
    font-size: 16px;
    justify-content: flex-start;
  }

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

  /* Footer adjustments */
  .footer-top-grid {
    grid-template-columns: 1fr; /* Single column on mobile */
    text-align: center;
  }

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

  .footer-col h3 {
    text-align: center;
  }

  .footer-nav {
    text-align: center;
  }

  .footer-nav li {
    display: inline-block; /* Inline links for better flow */
    margin: 0 8px 8px;
  }

  .footer-nav li a {
    white-space: nowrap;
  }

  /* Mobile content area 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;
  }
}