:root {
  --header-offset: 122px;
}
body {
  padding-top: var(--header-offset);
}
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #ffffff;
}
.header-top {
  background: linear-gradient(135deg, #c62828 0%, #e53935 100%);
  width: 100%;
}
.header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 30px;
  min-height: 60px;
}
.logo {
  font-size: 24px;
  font-weight: 800;
  color: #ffffff;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 1px;
  display: inline-block;
  flex-shrink: 0;
}
.logo:hover {
  color: #ffffff;
  opacity: 0.9;
}
.desktop-nav-buttons {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-left: auto;
}
.btn {
  display: inline-block;
  padding: 10px 20px;
  border-radius: 25px;
  font-weight: 700;
  font-size: 14px;
  text-decoration: none;
  text-align: center;
  transition: all 0.3s ease;
  cursor: pointer;
  border: none;
  min-height: 44px;
  box-sizing: border-box;
}
.btn-register {
  background: linear-gradient(180deg, #ff5a4f 0%, #e53935 100%);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(229, 57, 53, 0.4);
}
.btn-register:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(229, 57, 53, 0.5);
}
.btn-login {
  background: #ffffff;
  color: #e53935;
  border: 2px solid #e53935;
}
.btn-login:hover {
  background: #ffecec;
  transform: translateY(-2px);
}
.btn-download {
  background: linear-gradient(135deg, #ff9800 0%, #f57c00 100%);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(245, 124, 0, 0.4);
}
.btn-download:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(245, 124, 0, 0.5);
}
.main-nav {
  background: #ffffff;
  width: 100%;
  display: flex;
  flex-direction: row;
  border-bottom: 2px solid #e53935;
}
.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  padding: 6px 20px;
  gap: 4px;
  flex-wrap: wrap;
}
.nav-link {
  color: #333333;
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  padding: 8px 14px;
  border-radius: 6px;
  transition: all 0.3s ease;
  white-space: nowrap;
}
.nav-link:hover {
  background: #ffecec;
  color: #e53935;
  transform: translateY(-1px);
}
.mobile-nav-buttons {
  display: none;
}
.hamburger-menu {
  display: none;
  z-index: 1001;
  width: 44px;
  height: 44px;
  position: relative;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: transparent;
  border: none;
  padding: 0;
}
.hamburger-menu span {
  display: block;
  width: 24px;
  height: 3px;
  background-color: #ffffff;
  border-radius: 3px;
  transition: all 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, 0.7);
  z-index: 999;
}
.mobile-menu-overlay.active {
  display: block;
}
.site-footer {
  background: #2d2d2d;
  color: #ffffff;
  padding: 50px 20px 20px;
  margin-top: 40px;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  gap: 30px;
}
.footer-column {
  flex: 1 1 200px;
  min-width: 200px;
}
.footer-logo {
  font-size: 24px;
  font-weight: 800;
  color: #ff5a4f;
  margin: 0 0 15px 0;
  text-transform: uppercase;
}
.footer-column h4 {
  color: #ff5a4f;
  font-size: 16px;
  font-weight: 700;
  margin: 0 0 15px 0;
}
.footer-column p {
  font-size: 14px;
  color: #cccccc;
  line-height: 1.6;
  margin: 0 0 15px 0;
}
.footer-nav {
  list-style: none;
  padding: 0;
  margin: 0;
}
.footer-nav li {
  margin-bottom: 10px;
}
.footer-nav a {
  color: #cccccc;
  text-decoration: none;
  font-size: 14px;
  transition: all 0.3s ease;
}
.footer-nav a:hover {
  color: #ff5a4f;
  padding-left: 5px;
}
.footer-contact {
  list-style: none;
  padding: 0;
  margin: 0;
}
.footer-contact li {
  color: #cccccc;
  font-size: 14px;
  margin-bottom: 10px;
}
.footer-copyright {
  border-top: 1px solid #444444;
  padding-top: 20px;
  text-align: center;
  margin-top: 20px;
  flex-basis: 100%;
  color: #999999;
  font-size: 14px;
}
@media (max-width: 768px) {
  :root {
    --header-offset: 110px;
  }
  .site-header {
    min-height: auto;
  }
  .header-container {
    width: 100%;
    max-width: none;
    padding: 10px 15px;
    min-height: 60px;
    justify-content: flex-start;
    gap: 10px;
  }
  .logo {
    font-size: 18px;
    flex: 1;
    text-align: center;
    order: 2;
    padding: 0 5px;
  }
  .desktop-nav-buttons {
    display: none;
  }
  .hamburger-menu {
    display: flex;
    order: 1;
  }
  .header-top::before {
    content: '';
    flex: 0 0 44px;
    order: 0;
  }
  .mobile-nav-buttons {
    display: flex;
    justify-content: center;
    gap: 8px;
    padding: 10px 15px;
    background: #ffffff;
    border-bottom: 1px solid #e0e0e0;
    width: 100%;
    order: 4;
    z-index: 1000;
  }
  .mobile-nav-buttons .btn {
    flex: 1;
    max-width: 150px;
    padding: 10px 10px;
    font-size: 13px;
    min-height: 44px;
  }
  .main-nav {
    display: none;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    width: 280px;
    height: 100vh;
    height: 100dvh;
    background: #ffffff;
    padding: 80px 20px 30px 20px;
    overflow-y: auto;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    z-index: 1000;
    box-shadow: 2px 0 15px rgba(0, 0, 0, 0.2);
    border-bottom: none;
    border-right: 2px solid #e53935;
  }
  .main-nav.active {
    display: block;
    transform: translateX(0);
  }
  .nav-container {
    width: 100%;
    max-width: none;
    flex-direction: column;
    align-items: flex-start;
    padding: 0;
    gap: 0;
  }
  .nav-link {
    display: block;
    width: 100%;
    padding: 15px 15px;
    font-size: 16px;
    border-bottom: 1px solid #f0f0f0;
    border-radius: 0;
    color: #333333;
  }
  .nav-link:hover {
    background: #ffecec;
    color: #e53935;
    transform: none;
  }
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
  body {
    overflow-x: hidden;
    padding-top: var(--header-offset);
  }
  .site-footer {
    padding: 40px 15px 15px;
  }
  .footer-container {
    flex-direction: column;
    gap: 20px;
  }
  .footer-column {
    flex: 1 1 100%;
    min-width: 100%;
  }
}
/* 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;
}