:root { --primary: #2F6BFF; --secondary: #6FA3FF; --btn-gradient: linear-gradient(180deg, #4A8BFF 0%, #2F6BFF 100%); --bg: #F4F7FB; --card-bg: #FFFFFF; --text-main: #1F2D3D; --border: #D6E2FF; --glow: #A5C4FF; --header-offset: 122px; }
* { box-sizing: border-box; margin: 0; padding: 0; }
body { padding-top: var(--header-offset); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; background-color: var(--bg); color: var(--text-main); }
.site-header { position: fixed; top: 0; left: 0; width: 100%; z-index: 1000; box-shadow: 0 4px 20px rgba(47, 107, 255, 0.18); background-color: #FFFFFF; }
.header-top { background-color: #FFFFFF; width: 100%; border-bottom: 1px solid var(--border); }
.header-container { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; padding: 0 24px; min-height: 68px; }
.logo { display: inline-block; font-size: 26px; font-weight: 800; color: var(--primary); text-decoration: none; letter-spacing: -0.5px; }
.desktop-nav-buttons { display: flex; align-items: center; gap: 12px; margin-left: auto; }
.btn { display: inline-block; padding: 9px 22px; border-radius: 8px; font-size: 14px; font-weight: 600; text-decoration: none; text-align: center; transition: all 0.25s ease; border: none; cursor: pointer; white-space: nowrap; }
.btn-login { background-color: #FFFFFF; color: var(--primary); border: 1.5px solid var(--primary); }
.btn-login:hover { background-color: #EAF1FF; box-shadow: 0 4px 12px rgba(47, 107, 255, 0.25); }
.btn-register { background: var(--btn-gradient); color: #FFFFFF; box-shadow: 0 4px 12px rgba(47, 107, 255, 0.35); }
.btn-register:hover { box-shadow: 0 6px 18px rgba(47, 107, 255, 0.5); transform: translateY(-1px); }
.hamburger-menu { display: none; background: transparent; border: none; cursor: pointer; padding: 6px; flex-direction: column; justify-content: center; align-items: center; gap: 5px; width: 40px; height: 40px; z-index: 1002; }
.hamburger-menu span { display: block; width: 24px; height: 2.5px; background-color: var(--primary); border-radius: 2px; transition: all 0.3s ease; transform-origin: center; }
.hamburger-menu.active span:nth-child(1) { transform: translateY(7.5px) rotate(45deg); }
.hamburger-menu.active span:nth-child(2) { opacity: 0; }
.hamburger-menu.active span:nth-child(3) { transform: translateY(-7.5px) rotate(-45deg); }
.mobile-buttons { display: none; }
.main-nav { background-color: var(--primary); width: 100%; 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: rgba(255, 255, 255, 0.85); text-decoration: none; font-size: 14.5px; font-weight: 500; padding: 14px 14px; position: relative; transition: color 0.25s ease; white-space: nowrap; }
.nav-link:hover, .nav-link.active { color: #FFFFFF; }
.nav-link::after { content: ''; position: absolute; bottom: 6px; left: 50%; transform: translateX(-50%) scaleX(0); width: 70%; height: 2.5px; background-color: var(--glow); border-radius: 2px; transition: transform 0.25s ease; }
.nav-link:hover::after, .nav-link.active::after { transform: translateX(-50%) scaleX(1); }
.mobile-menu-overlay { display: none; }
.site-footer { background-color: #0F1E3D; color: #C9D6EE; padding: 50px 0 0; margin-top: 0; }
.footer-container { max-width: 1200px; margin: 0 auto; padding: 0 24px 40px; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; }
.footer-column { display: flex; flex-direction: column; }
.footer-brand .footer-logo { font-size: 26px; font-weight: 800; color: #FFFFFF; text-decoration: none; letter-spacing: -0.5px; margin-bottom: 14px; }
.footer-desc { font-size: 14px; line-height: 1.7; color: #A9BADB; max-width: 340px; }
.footer-title { font-size: 16px; font-weight: 700; color: #FFFFFF; margin-bottom: 16px; position: relative; padding-bottom: 10px; }
.footer-title::after { content: ''; position: absolute; bottom: 0; left: 0; width: 36px; height: 2.5px; background: var(--btn-gradient); border-radius: 2px; }
.footer-nav { display: flex; flex-direction: column; gap: 10px; }
.footer-nav a { color: #A9BADB; text-decoration: none; font-size: 14px; transition: color 0.2s ease, padding-left 0.2s ease; }
.footer-nav a:hover { color: #FFFFFF; padding-left: 4px; }
.footer-bottom { border-top: 1px solid rgba(255, 255, 255, 0.12); padding: 20px 24px; text-align: center; }
.footer-copyright { font-size: 13.5px; color: #8FA3C8; }
body.no-scroll { overflow: hidden; }
@media (max-width: 768px) {
  :root { --header-offset: 110px; }
  .header-container { width: 100%; max-width: none; padding: 0 15px; min-height: 60px; justify-content: space-between; }
  .logo { flex: 1; text-align: center; font-size: 22px; order: 2; }
  .hamburger-menu { display: flex; order: 1; }
  .desktop-nav-buttons { display: none; }
  .mobile-buttons { display: flex; justify-content: center; align-items: center; gap: 10px; padding: 10px 15px; background-color: #FFFFFF; border-bottom: 1px solid var(--border); }
  .mobile-buttons .btn { flex: 1; padding: 9px 12px; font-size: 13.5px; max-width: 160px; }
  .main-nav { display: none; position: fixed; top: 0; left: 0; width: 82%; max-width: 320px; height: 100vh; background-color: #FFFFFF; z-index: 1001; transform: translateX(-100%); transition: transform 0.3s ease; flex-direction: column; padding-top: 20px; box-shadow: 4px 0 24px rgba(15, 30, 61, 0.25); overflow-y: auto; }
  .main-nav.active { display: block; transform: translateX(0); }
  .nav-container { width: 100%; max-width: none; flex-direction: column; justify-content: flex-start; align-items: stretch; padding: 10px 0 40px; min-height: auto; }
  .nav-link { color: var(--text-main); font-size: 15.5px; font-weight: 600; padding: 14px 24px; border-bottom: 1px solid #EEF3FC; }
  .nav-link:hover, .nav-link.active { color: var(--primary); background-color: #F0F5FF; }
  .nav-link::after { display: none; }
  .mobile-menu-overlay { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100vh; background-color: rgba(15, 30, 61, 0.55); z-index: 999; opacity: 0; transition: opacity 0.3s ease; }
  .mobile-menu-overlay.active { display: block; opacity: 1; }
  .footer-container { grid-template-columns: 1fr; gap: 30px; padding: 0 20px 30px; }
  .footer-desc { max-width: 100%; }
  .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;
  }
}
/* 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;
}