:root { --header-offset: 122px; --primary-color: #E53935; --secondary-color: #FF5A4F; }
* { margin: 0; padding: 0; box-sizing: border-box; }
body { padding-top: var(--header-offset); margin: 0; font-family: 'Segoe UI', Arial, sans-serif; background-color: #F5F7FA; color: #333333; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
.site-header { position: fixed; top: 0; left: 0; width: 100%; z-index: 1000; box-shadow: 0 2px 8px rgba(0,0,0,0.15); }
.header-top { width: 100%; background-color: #B71C1C; display: flex; min-height: 68px; }
.header-container { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; width: 100%; padding-left: 24px; padding-right: 24px; }
.logo { font-size: 24px; font-weight: 800; color: #FFFFFF; letter-spacing: 1px; display: inline-block; text-decoration: none; text-transform: uppercase; background: linear-gradient(180deg, #FFD54F 0%, #FFB300 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.logo:hover { opacity: 0.9; }
.desktop-nav-buttons { display: flex; gap: 10px; align-items: center; }
.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 36px; padding: 4px 18px; border-radius: 4px; font-size: 14px; font-weight: 600; text-decoration: none; transition: all 0.3s ease; cursor: pointer; border: none; line-height: 1.2; }
.btn-register { background: linear-gradient(180deg, #FF5A4F 0%, #E53935 100%); color: #FFFFFF; }
.btn-register:hover { opacity: 0.9; transform: translateY(-1px); }
.btn-login { background: linear-gradient(180deg, #FFD54F 0%, #FFB300 100%); color: #333333; }
.btn-login:hover { opacity: 0.9; transform: translateY(-1px); }
.btn-download { background: linear-gradient(180deg, #FF5A4F 0%, #E53935 100%); color: #FFFFFF; }
.btn-download:hover { opacity: 0.9; transform: translateY(-1px); }
.main-nav { width: 100%; background-color: #FFFFFF; display: flex; min-height: 52px; border-top: 2px solid #E53935; border-bottom: 1px solid #E0E0E0; }
.nav-container { max-width: 1200px; margin: 0 auto; display: flex; flex-direction: row; justify-content: center; align-items: center; padding: 0 20px; width: 100%; }
.nav-menu { display: flex; flex-direction: row; justify-content: center; align-items: center; gap: 0; margin: 0; padding: 0; list-style: none; }
.nav-menu li { position: relative; }
.nav-menu li a { display: block; padding: 14px 16px; font-size: 14px; font-weight: 500; color: #333333; border-bottom: 3px solid transparent; transition: color 0.3s ease, border-color 0.3s ease; white-space: nowrap; }
.nav-menu li a:hover { color: #E53935; border-bottom-color: #E53935; }
.nav-menu li a.active { color: #E53935; font-weight: 600; border-bottom-color: #E53935; }
.hamburger-menu { display: none; position: fixed; top: 21px; left: 15px; z-index: 1002; background: none; border: none; outline: none; padding: 0; min-width: 34px; height: 34px; cursor: pointer; flex-direction: column; justify-content: center; align-items: center; gap: 5px; }
.hamburger-menu span { display: block; width: 26px; height: 3px; background-color: #FFFFFF; border-radius: 2px; transition: transform 0.3s ease, opacity 0.3s ease; }
.hamburger-menu.active span:nth-child(1) { transform: translateY(8px) rotate(45deg); }
.hamburger-menu.active span:nth-child(2) { opacity: 0; }
.hamburger-menu.active span:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }
.mobile-menu-overlay { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background-color: rgba(0,0,0,0.5); z-index: 998; opacity: 0; transition: opacity 0.3s ease; }
.mobile-menu-overlay.active { display: block; opacity: 1; }
.mobile-nav-buttons { display: none; width: 100%; background: linear-gradient(180deg, #FF5A4F 0%, #E53935 100%); min-height: 48px; align-items: center; justify-content: space-around; gap: 10px; z-index: 999; border-top: 1px solid rgba(255,255,255,0.2); padding: 6px 10px; }
.mobile-nav-buttons .btn { min-height: 34px; padding: 2px 16px; font-size: 13px; flex: 1; max-width: 120px; }
.site-footer { width: 100%; background: linear-gradient(135deg, #1F2A44 0%, #1B1B2F 100%); color: #E0E0E0; position: relative; z-index: 1; }
.site-footer::before { content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 3px; background: linear-gradient(90deg, #E53935 0%, #FF5A4F 50%, #E53935 100%); }
.footer-container { max-width: 1200px; margin: 0 auto; display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 30px; padding: 50px 24px 30px; }
.footer-column h3 { color: #FFFFFF; font-size: 16px; font-weight: 600; margin-bottom: 20px; padding-bottom: 10px; border-bottom: 2px solid #E53935; display: inline-block; }
.footer-column ul { padding: 0; margin: 0; list-style: none; }
.footer-column ul li { margin-bottom: 10px; }
.footer-column ul li a { color: #B0B0C0; text-decoration: none; transition: color 0.3s ease; font-size: 14px; }
.footer-column ul li a:hover { color: #FF5A4F; }
.footer-logo { font-size: 26px; font-weight: 800; color: #FFFFFF; text-decoration: none; display: inline-block; margin-bottom: 15px; }
.footer-logo:hover { color: #FF5A4F; }
.footer-description { font-size: 14px; line-height: 1.6; color: #B0B0C0; opacity: 0.8; display: flex; flex-direction: column; }
.footer-badges { display: flex; gap: 10px; margin-top: 15px; }
.badge { background: #E53935; color: #FFFFFF; padding: 3px 8px; border-radius: 4px; font-size: 12px; font-weight: 500; display: inline-block; }
.footer-bottom { border-top: 1px solid #333; padding: 20px 24px; text-align: center; }
.copyright { font-size: 14px; color: #B0B0C0; margin-bottom: 8px; }
.disclaimer { font-size: 12px; color: #888; opacity: 0.7; }
@media (max-width: 768px) {
  :root { --header-offset: 158px; }
  .mobile-nav-buttons .btn { min-height: 34px; padding: 2px 12px; font-size: 13px; flex: 1; max-width: 100px; }
  .hamburger-menu { display: flex; }
  .mobile-nav-buttons { display: flex; }
  .site-header { min-height: auto; }
  .header-top { min-height: 60px; }
  .header-container { width: 100%; max-width: none; padding-left: 55px; padding-right: 15px; justify-content: space-between; }
  .header-container .logo { margin-right: 0; font-size: 20px; }
  .btn { padding: 4px 14px; font-size: 13px; }
  .desktop-nav-buttons { display: none; }
  .main-nav { display: none; position: fixed; top: 0; left: 0; width: 280px; height: 100%; min-height: 100vh; background-color: #FFFFFF; flex-direction: column; transform: translateX(-110%); transition: transform 0.3s ease; z-index: 1000; border-top: none; border-right: 2px solid #E53935; }
  .main-nav.active, .main-nav.open { display: block; transform: translateX(0); }
  .nav-container { width: 100%; max-width: none; padding: 0; display: block; }
  .nav-menu { display: flex; flex-direction: column; align-items: stretch; width: 100%; padding-top: 60px; }
  .nav-menu li a { padding: 14px 20px; border-bottom: 1px solid #F0F0F0; border-left: 3px solid transparent; }
  .nav-menu li a:hover { color: #E53935; border-bottom-color: #F0F0F0; border-left-color: #E53935; background: #FAFAFA; }
  .nav-menu li a.active { color: #E53935; border-bottom-color: #F0F0F0; border-left-color: #E53935; background: #FDF3F3; }
  .footer-container { grid-template-columns: 1fr 1fr; gap: 20px; padding: 40px 15px 25px; }
  .header-top { width: 100%; }
  body { overflow-x: hidden; }
  .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;
}