:root { --header-offset: 122px; }
body { padding-top: var(--header-offset); }
@media (max-width: 768px) { :root { --header-offset: 110px; } }
.site-header { position: fixed; top: 0; left: 0; width: 100%; z-index: 1000; box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15); background: #FFFFFF; }
.header-top { background: linear-gradient(135deg, #2F6BFF 0%, #1a4fdb 100%); width: 100%; }
.header-container { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; padding: 0 24px; min-height: 68px; }
.logo { font-size: 1.8rem; font-weight: 800; color: #FFFFFF; letter-spacing: 1px; text-decoration: none; display: block; line-height: 68px; }
.logo:hover { color: #FFFFFF; opacity: 0.9; }
.desktop-nav-buttons { display: flex; gap: 12px; align-items: center; }
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 10px 24px; border-radius: 50px; font-weight: 600; font-size: 0.9rem; text-decoration: none; border: none; cursor: pointer; transition: all 0.3s ease; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1); }
.btn-register { background: linear-gradient(180deg, #4A8BFF 0%, #2F6BFF 100%); color: #FFFFFF; }
.btn-register:hover { background: linear-gradient(180deg, #6FA3FF 0%, #4A8BFF 100%); transform: translateY(-2px); box-shadow: 0 6px 16px rgba(47, 107, 255, 0.4); }
.btn-login { background: #1F2D3D; color: #FFFFFF; border: 2px solid #FFFFFF; }
.btn-login:hover { background: #2F6BFF; transform: translateY(-2px); box-shadow: 0 6px 16px rgba(47, 107, 255, 0.4); }
.main-nav { width: 100%; background: linear-gradient(180deg, #F4F7FB 0%, #FFFFFF 100%); border-bottom: 2px solid #D6E2FF; display: flex; }
.nav-container { max-width: 1200px; margin: 0 auto; display: flex; flex-direction: row; justify-content: center; align-items: center; padding: 0 24px; min-height: 52px; flex-wrap: wrap; }
.nav-link { color: #1F2D3D; font-size: 0.9rem; font-weight: 500; text-decoration: none; padding: 8px 12px; border-radius: 8px; transition: all 0.3s ease; position: relative; margin: 4px 2px; white-space: nowrap; }
.nav-link:hover { color: #2F6BFF; background: rgba(47, 107, 255, 0.1); }
.nav-link::after { content: ''; position: absolute; bottom: 2px; left: 12px; right: 12px; height: 2px; background: #2F6BFF; transform: scaleX(0); transform-origin: center; transition: transform 0.3s ease; }
.nav-link:hover::after { transform: scaleX(1); }
.hamburger-menu { display: none; }
.mobile-menu-overlay { display: none; }
.mobile-nav-buttons { display: none; }
@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; }
  .site-header { background: linear-gradient(180deg, #F4F7FB 0%, #FFFFFF 100%); }
  .header-top { background: linear-gradient(135deg, #2F6BFF 0%, #1a4fdb 100%); }
  .header-container { width: 100%; max-width: none; padding: 0 20px; min-height: 60px; position: relative; }
  .logo { font-size: 1.4rem; line-height: 60px; position: absolute; left: 50%; transform: translateX(-50%); }
  .desktop-nav-buttons { display: none; }
  .hamburger-menu { display: flex; flex-direction: column; justify-content: center; gap: 5px; width: 40px; height: 40px; background: transparent; border: none; cursor: pointer; z-index: 1002; padding: 0; position: absolute; left: 12px; top: 10px; }
  .hamburger-line { display: block; width: 24px; height: 2.5px; background: #FFFFFF; border-radius: 2px; transition: all 0.3s ease; margin: 0 auto; }
  .hamburger-menu.active .hamburger-line:nth-child(1) { transform: translateY(7.5px) rotate(45deg); }
  .hamburger-menu.active .hamburger-line:nth-child(2) { opacity: 0; }
  .hamburger-menu.active .hamburger-line:nth-child(3) { transform: translateY(-7.5px) rotate(-45deg); }
  .main-nav { display: none; position: fixed; top: 0; left: 0; width: 80%; max-width: 320px; height: 100vh; height: 100dvh; background: #FFFFFF; flex-direction: column; justify-content: flex-start; align-items: stretch; padding: 80px 20px 30px; overflow-y: auto; z-index: 1001; transform: translateX(-100%); transition: transform 0.3s ease-in-out; box-shadow: 2px 0 20px rgba(0, 0, 0, 0.2); min-height: 100vh; }
  .main-nav.active { display: flex; transform: translateX(0); }
  .nav-container { width: 100%; max-width: none; flex-direction: column; justify-content: flex-start; align-items: center; padding: 0; min-height: auto; }
  .nav-link { font-size: 1rem; padding: 12px 16px; width: 100%; text-align: center; border-radius: 8px; margin: 4px 0; }
  .nav-link:hover { background: rgba(47, 107, 255, 0.1); }
  .mobile-menu-overlay { display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 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; padding: 8px 20px 8px; justify-content: center; background: #FFFFFF; border-bottom: 1px solid #D6E2FF; width: 100%; box-sizing: border-box; }
  .mobile-nav-buttons .btn { padding: 8px 16px; font-size: 0.8rem; min-width: 100px; }
}
.site-footer { background: #1F2D3D; color: #FFFFFF; padding: 0; margin-top: 40px; position: relative; }
.footer-container { max-width: 1200px; margin: 0 auto; padding: 50px 24px 30px; display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; }
.footer-brand { max-width: 360px; }
.footer-logo { font-size: 1.8rem; font-weight: 800; color: #FFFFFF; text-decoration: none; display: inline-block; margin-bottom: 16px; }
.footer-description { color: rgba(255, 255, 255, 0.8); font-size: 0.9rem; line-height: 1.8; margin: 0; }
.footer-title { font-size: 1rem; font-weight: 600; color: #FFFFFF; margin-bottom: 15px; position: relative; padding-bottom: 8px; }
.footer-title::after { content: ''; position: absolute; bottom: 0; left: 0; width: 30px; height: 2px; background: #6FA3FF; }
.footer-nav { list-style: none; padding: 0; margin: 0; text-align: left; }
.footer-nav li { margin-bottom: 10px; text-align: left; padding-left: 0; }
.footer-nav li::before { display: none; }
.footer-nav a { color: rgba(255, 255, 255, 0.8); text-decoration: none; font-size: 0.9rem; transition: all 0.3s ease; display: inline-block; }
.footer-nav a:hover { color: #6FA3FF; padding-left: 4px; }
.footer-contact p { color: rgba(255, 255, 255, 0.8); font-size: 0.9rem; margin-bottom: 8px; }
.footer-bottom { border-top: 1px solid rgba(255, 255, 255, 0.1); padding: 18px 24px; text-align: center; background: rgba(0, 0, 0, 0.2); }
.footer-bottom p { color: rgba(255, 255, 255, 0.6); font-size: 0.85rem; margin: 4px 0; }
.footer-warning { color: #A5C4FF; font-size: 0.8rem !important; }
@media (max-width: 768px) {
  .footer-container { grid-template-columns: 1fr 1fr; gap: 30px; padding: 40px 20px 20px; }
  .footer-brand { grid-column: 1 / -1; }
  .footer-bottom { padding: 15px 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;
}