:root { --primary: #2F6BFF; --primary-light: #6FA3FF; --primary-dark: #1a4fd6; --header-offset: 166px; --gradient-btn: linear-gradient(180deg, #4A8BFF 0%, #2F6BFF 100%); }
* { 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: #F4F7FB; color: #1F2D3D; overflow-x: hidden; }
.site-header { position: fixed; top: 0; left: 0; width: 100%; z-index: 1000; background: #ffffff; box-shadow: 0 4px 20px rgba(31, 45, 61, 0.12); }
.header-top { background: #ffffff; width: 100%; }
.header-container { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; padding: 8px 24px; min-height: 68px; }
.logo { font-size: 1.6rem; font-weight: 800; color: var(--primary); text-decoration: none; letter-spacing: -0.5px; display: inline-block; line-height: 1.3; white-space: nowrap; }
.logo:hover { color: var(--primary); opacity: 0.9; }
.main-nav { display: flex; background: var(--primary); width: 100%; min-height: 52px; transition: all 0.3s ease; }
.nav-container { max-width: 1200px; margin: 0 auto; display: flex; flex-direction: row; justify-content: center; align-items: center; flex-wrap: wrap; gap: 4px; padding: 6px 20px; width: 100%; }
.main-nav a { color: #ffffff; text-decoration: none; font-size: 0.92rem; font-weight: 600; padding: 8px 16px; border-radius: 6px; transition: background 0.3s, color 0.3s; white-space: nowrap; }
.main-nav a:hover { background: rgba(255,255,255,0.2); color: #ffffff; }
.desktop-nav-buttons { display: flex; align-items: center; gap: 10px; }
.btn { text-decoration: none; display: inline-block; padding: 10px 20px; border-radius: 8px; font-weight: 700; font-size: 0.9rem; border: none; cursor: pointer; transition: transform 0.2s, box-shadow 0.2s, opacity 0.2s; text-align: center; line-height: normal; }
.btn:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(47, 107, 255, 0.4); }
.btn-register { background: var(--gradient-btn); color: #ffffff; box-shadow: 0 4px 15px rgba(47, 107, 255, 0.3); }
.btn-login { background: #ffffff; color: var(--primary); border: 2px solid var(--primary); box-shadow: 0 2px 8px rgba(47, 107, 255, 0.15); }
.btn-login:hover { background: #F0F4FF; }
.mobile-nav-buttons { display: none; background: #ffffff; padding: 8px 16px; gap: 10px; width: 100%; z-index: 999; border-bottom: 1px solid #D6E2FF; }
.hamburger-menu { display: none; position: fixed; top: 14px; left: 16px; width: 40px; height: 40px; cursor: pointer; z-index: 1003; background: #ffffff; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); padding: 10px 8px; align-items: center; justify-content: center; }
.hamburger-menu span { display: block; width: 24px; height: 2.5px; background: var(--primary); margin-bottom: 5px; border-radius: 3px; transition: transform 0.3s ease, opacity 0.3s; }
.hamburger-menu span:last-child { margin-bottom: 0; }
.hamburger-menu.active span { background: var(--primary); }
.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-menu-overlay { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.55); z-index: 1001; opacity: 0; transition: opacity 0.3s ease; }
.mobile-menu-overlay.active { opacity: 1; }
.mobile-menu-overlay.visible { display: block; }
.site-footer { background: #1F2D3D; margin-top: 0; padding: 40px 0 0; color: #d1d8e0; }
.footer-container { max-width: 1200px; margin: 0 auto; padding: 0 24px; display: grid; grid-template-columns: 1.4fr 1fr 1.2fr; gap: 32px; }
.footer-column h3 { color: #ffffff; font-size: 1.1rem; margin-bottom: 16px; padding-bottom: 8px; position: relative; }
.footer-column h3::after { content: ''; position: absolute; bottom: 0; left: 0; width: 30px; height: 2px; background: var(--primary-light); }
.footer-logo { font-size: 1.5rem; font-weight: 800; color: #ffffff; text-decoration: none; display: inline-block; margin-bottom: 12px; }
.footer-info p { font-size: 0.88rem; line-height: 1.6; }
.footer-nav { display: flex; flex-direction: column; gap: 8px; }
.footer-nav a { color: #b0b8c4; text-decoration: none; font-size: 0.88rem; transition: color 0.3s, padding-left 0.3s; }
.footer-nav a:hover { color: var(--primary-light); padding-left: 6px; }
.footer-contact p { font-size: 0.88rem; margin-bottom: 8px; line-height: 1.5; }
.footer-bottom { background: #141d2a; margin-top: 32px; padding: 16px 24px; text-align: center; font-size: 0.85rem; color: #8a97a6; border-top: 1px solid #2a3644; }
body.no-scroll { overflow: hidden; }
@media (max-width: 992px) { .main-nav a { padding: 8px 12px; font-size: 0.85rem; } .header-container { padding: 8px 16px; } }
@media (max-width: 768px) {
  :root { --header-offset: 146px; }
  .site-header { display: block; }
  .header-top { background: #ffffff; }
  .header-container { width: 100%; max-width: none; min-height: 60px; padding: 8px 16px; justify-content: center; position: relative; }
  .logo { font-size: 1.2rem; text-align: center; }
  .main-nav { display: none; position: fixed; top: 0; right: 0; width: 280px; height: 100%; background: #ffffff; flex-direction: column; justify-content: flex-start; align-items: stretch; padding: 80px 20px 30px; z-index: 1002; transform: translateX(100%); opacity: 0; visibility: hidden; transition: transform 0.4s cubic-bezier(0.77, 0.2, 0.05, 1), opacity 0.3s, visibility 0.4s; box-shadow: -6px 0 20px rgba(0,0,0,0.15); }
  .main-nav.active { display: block; opacity: 1; visibility: visible; transform: translateX(0); }
  .nav-container { display: block; width: 100%; max-width: none; padding: 0; }
  .main-nav a { display: block; color: #1F2D3D; padding: 12px 15px; font-size: 1rem; border-bottom: 1px solid #f0f0f0; border-radius: 0; }
  .main-nav a:hover { background: #f0f4ff; color: var(--primary); }
  .main-nav a:last-of-type { border-bottom: none; }
  .desktop-nav-buttons { display: none; }
  .mobile-nav-buttons { display: flex; justify-content: center; align-items: center; margin: 0 auto; }
  .mobile-nav-buttons .btn { flex: 1; max-width: 180px; font-size: 0.85rem; padding: 8px 14px; }
  .hamburger-menu { display: flex; }
  .mobile-menu-overlay.active { display: block; }
  .mobile-menu-overlay.visible { display: block; }
  .site-footer { padding-top: 30px; color: #c8d0da; }
  .footer-container { display: block; padding: 0 20px; }
  .footer-column { margin-bottom: 28px; }
  .footer-column h3 { font-size: 1rem; margin-bottom: 12px; }
  .footer-nav a { font-size: 0.86rem; }
  .footer-contact p { font-size: 0.85rem; }
  .footer-bottom { padding: 14px 16px; font-size: 0.8rem; }
  .page-content img { max-width: 100% !important; height: auto !important; display: block; }
  .page-content { overflow-x: hidden; max-width: 100%; }
  body { overflow-x: hidden; }
}
@media (min-width: 769px) and (max-width: 1024px) { .mobile-nav-buttons { display: none; } }
/* 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;
}