:root {
  --primary: #2F6BFF;
  --primary-light: #6FA3FF;
  --primary-dark: #1B4FCC;
  --btn-gradient: linear-gradient(180deg, #4A8BFF 0%, #2F6BFF 100%);
  --text-main: #1F2D3D;
  --text-black: #000000;
  --card-bg: #FFFFFF;
  --bg-main: #F4F7FB;
  --border-color: #D6E2FF;
  --glow: #A5C4FF;
  --header-offset: 122px;
  --footer-bg: #1B2A4A;
  --footer-text: #C8D4E5;
  --footer-heading: #FFFFFF;
  --footer-border: rgba(255,255,255,0.1);
}
body {
  padding-top: var(--header-offset);
  margin: 0;
  font-family: 'Segoe UI', Roboto, Arial, sans-serif;
  background: var(--bg-main);
  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, 0.25);
  display: flex;
  flex-direction: column;
}
.header-top {
  background: linear-gradient(135deg, #1B4FCC, #2F6BFF);
  width: 100%;
}
.header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-left: 24px;
  padding-right: 24px;
  min-height: 68px;
}
.logo {
  display: inline-block;
  font-size: 28px;
  font-weight: 800;
  color: #FFFFFF;
  text-decoration: none;
  letter-spacing: -0.5px;
  text-shadow: 0 2px 8px rgba(0,0,0,0.2);
  line-height: 1.2;
}
.logo:hover {
  color: #FFD700;
  text-decoration: none;
}
.desktop-nav-buttons {
  display: flex;
  align-items: center;
  gap: 10px;
}
.btn {
  display: inline-block;
  padding: 10px 24px;
  font-size: 14px;
  font-weight: 700;
  border-radius: 24px;
  text-decoration: none;
  color: #FFFFFF;
  transition: all 0.3s ease;
  font-family: inherit;
  min-width: 90px;
  text-align: center;
  box-shadow: 0 4px 14px rgba(0,0,0,0.2);
}
.btn-register {
  background: var(--btn-gradient);
  border-radius: 8px;
}
.btn-register:hover {
  background: linear-gradient(180deg, #2F6BFF, #1B4FCC);
  transform: translateY(-2px);
  color: #FFFFFF;
}
.btn-login {
  background: var(--btn-gradient);
  border-radius: 8px;
}
.btn-login:hover {
  background: linear-gradient(180deg, #2F6BFF, #1B4FCC);
  transform: translateY(-2px);
  color: #FFFFFF;
}
.main-nav {
  background: #1B4FCC;
  width: 100%;
  display: flex;
  flex-direction: row;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  min-height: 52px;
}
.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  padding: 6px 20px;
  gap: 2px;
  flex-wrap: wrap;
}
.nav-link {
  color: #FFFFFF;
  text-decoration: none;
  font-size: 15px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 6px;
  white-space: nowrap;
  transition: background-color 0.3s ease, color 0.3s ease;
}
.nav-link:hover {
  background-color: #6FA3FF;
  color: #FFFFFF;
  text-decoration: none;
}
.nav-link.active {
  background-color: #2F6BFF;
  color: #FFFFFF;
  font-weight: 700;
}
.mobile-nav-buttons {
  display: none;
}
.hamburger-menu {
  display: none;
}
.mobile-menu-overlay {
  display: none;
}
@media (max-width: 768px) {
  :root {
    --header-offset: 110px;
  }
  .site-header {
    background: linear-gradient(135deg, #1B4FCC, #2F6BFF);
  }
  .header-top {
    background: transparent;
  }
  .header-container {
    width: 100%;
    max-width: none;
    padding-left: 15px;
    padding-right: 15px;
    min-height: 60px;
    justify-content: flex-start;
    gap: 10px;
  }
  .logo {
    font-size: 24px;
    flex: 1;
    text-align: center;
    padding: 0;
  }
  .desktop-nav-buttons {
    display: none;
  }
  .main-nav {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 80%;
    max-width: 360px;
    height: 100%;
    background: #1B4FCC;
    flex-direction: column;
    padding-top: 30px;
    box-shadow: 4px 0 20px rgba(0,0,0,0.3);
    z-index: 1100;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    overflow-y: auto;
    gap: 4px;
  }
  .main-nav.active {
    display: block;
    transform: translateX(0);
  }
  .nav-container {
    width: 100%;
    max-width: none;
    flex-direction: column;
    align-items: center;
    padding: 0;
    gap: 0;
  }
  .nav-link {
    display: block;
    width: 100%;
    text-align: center;
    padding: 15px 20px;
    font-size: 16px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    color: #FFFFFF;
  }
  .nav-link:hover {
    background-color: #2F6BFF;
  }
  .nav-link.active {
    background-color: #2F6BFF;
  }
  .mobile-nav-buttons {
    display: flex;
    justify-content: center;
    background: #F4F7FB;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
    min-height: 48px;
    align-items: center;
  }
  .mobile-buttons-container {
    display: flex;
    gap: 10px;
    justify-content: center;
    width: 100%;
    padding: 0 15px;
  }
  .mobile-buttons-container .btn {
    flex: 1;
    max-width: 160px;
    font-size: 13px;
    min-width: 80px;
    padding: 10px 12px;
    text-align: center;
  }
  .hamburger-menu {
    display: inline-flex;
    width: 42px;
    height: 42px;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: transparent;
    border: 2px solid #FFFFFF;
    border-radius: 50%;
    cursor: pointer;
    padding: 8px;
    z-index: 1200;
    position: relative;
    flex-shrink: 0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.3);
  }
  .hamburger-menu span {
    display: block;
    width: 20px;
    height: 2px;
    background: #FFFFFF;
    margin: 3px auto;
    border-radius: 4px;
    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: rgba(0,0,0,0.6);
    z-index: 1050;
    cursor: pointer;
  }
  .mobile-menu-overlay.active {
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  body {
    overflow-x: hidden;
  }
}
.site-footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  padding: 40px 20px 20px;
  font-family: 'Segoe UI', Roboto, Arial, sans-serif;
  border-top: 4px solid var(--primary);
}
.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 40px;
}
.footer-logo {
  font-size: 32px;
  font-weight: 800;
  color: #FFFFFF;
  text-decoration: none;
  letter-spacing: -0.5px;
  display: inline-block;
  margin-bottom: 12px;
}
.footer-logo:hover {
  color: #FFD700;
  text-decoration: none;
}
.footer-desc {
  font-size: 14px;
  line-height: 1.6;
  margin: 0 0 15px;
  color: var(--footer-text);
}
.footer-copyright {
  font-size: 13px;
  color: rgba(255,255,255,0.6);
  margin: 15px 0 0;
}
.footer-heading {
  font-size: 20px;
  font-weight: 600;
  color: var(--footer-heading);
  margin: 0 0 15px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.footer-nav {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.footer-nav a {
  color: var(--footer-text);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.3s ease, padding-left 0.3s ease;
  line-height: 1.5;
}
.footer-nav a:hover {
  color: #FFFFFF;
  text-decoration: underline;
  padding-left: 4px;
}
@media (max-width: 768px) {
  .footer-container {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    width: 100%;
    max-width: none;
  }
  .footer-column.footer-brand {
    grid-column: 1 / -1;
    text-align: center;
    padding-bottom: 16px;
  }
  .footer-heading {
    font-size: 16px;
    text-align: left;
  }
  .footer-desc {
    text-align: center;
    font-size: 13px;
  }
  .footer-nav a {
    font-size: 13px;
  }
}
@media (max-width: 480px) {
  .footer-container {
    grid-template-columns: 1fr;
  }
  .footer-column.footer-brand {
    text-align: left;
  }
  .footer-desc {
    text-align: left;
  }
  .footer-heading {
    text-align: left;
  }
}
/* 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;
}