:root {
  --header-offset: 120px;
  --color-primary: #113B7A;
  --color-secondary: #1D5FD1;
  --color-deep-navy: #08162B;
  --color-card-bg: #10233F;
  --color-text-main: #F3F8FF;
  --color-text-secondary: #AFC4E8;
  --color-border: #244D84;
  --color-glow: #4FA8FF;
  --color-gold: #F2C14E;
  --color-divider: #1B3357;
  --btn-gradient: linear-gradient(180deg, #2B73F6 0%, #1144A6 100%);
  color-scheme: dark;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--color-deep-navy);
  color: var(--color-text-main);
  padding-top: var(--header-offset);
  margin: 0;
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background-color: var(--color-deep-navy);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.6);
  border-bottom: 1px solid var(--color-border);
}

.header-top {
  width: 100%;
  background: rgba(8, 22, 43, 0.9);
  backdrop-filter: blur(5px);
  border-bottom: 1px solid var(--color-divider);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 24px;
  gap: 16px;
  flex-wrap: nowrap;
}

.logo {
  font-size: 2.2rem;
  font-weight: 900;
  color: #ffffff;
  text-decoration: none;
  letter-spacing: 1px;
  text-shadow: 0 0 20px rgba(79, 168, 255, 0.5);
  flex-shrink: 0;
  line-height: 1.1;
}

.logo:hover {
  color: var(--color-glow);
}

.desktop-nav-buttons {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-shrink: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.2s ease-in-out;
  white-space: nowrap;
  text-transform: none;
}

.btn-register {
  background: var(--btn-gradient);
  color: #fff;
  box-shadow: 0 0 12px rgba(43, 115, 246, 0.3);
}
.btn-register:hover {
  filter: brightness(1.15);
  box-shadow: 0 0 20px rgba(43, 115, 246, 0.6);
}

.btn-login {
  background: var(--color-gold);
  color: #08162B;
}
.btn-login:hover {
  filter: brightness(1.1);
}

.btn-download {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  border: 1px solid var(--color-border);
}
.btn-download:hover {
  background: rgba(255, 255, 255, 0.2);
  border-color: var(--color-glow);
}

.btn {
  padding: 10px 20px;
  font-size: 0.9rem;
}

.desktop-nav-buttons .btn {
  padding: 10px 20px;
  font-size: 0.9rem;
}

.main-nav {
  background-color: var(--color-primary);
  width: 100%;
  display: flex;
  justify-content: center;
  border-bottom: 1px solid var(--color-border);
}

.nav-container {
  max-width: 1200px;
  width: 100%;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  gap: 4px;
  padding: 6px 20px;
  flex-wrap: wrap;
}

.nav-container a {
  color: rgba(243, 248, 255, 0.9);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: 4px;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.nav-container a:hover {
  background: rgba(79, 168, 255, 0.15);
  color: #ffffff;
}

.mobile-nav-buttons {
  display: none;
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 30px;
  height: 22px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 1001;
  position: relative;
}

.mobile-menu-toggle .bar {
  display: block;
  width: 100%;
  height: 3px;
  background-color: #fff;
  border-radius: 3px;
  transition: all 0.3s ease;
}

.mobile-menu-toggle.active .bar:nth-child(1) {
  transform: translateY(9px) rotate(45deg);
}
.mobile-menu-toggle.active .bar:nth-child(2) {
  opacity: 0;
}
.mobile-menu-toggle.active .bar:nth-child(3) {
  transform: translateY(-9px) 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: 998;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.mobile-menu-overlay.active {
  display: block;
  opacity: 1;
}

.site-footer {
  background-color: var(--color-deep-navy);
  border-top: 1px solid var(--color-border);
  padding: 40px 24px 20px;
  width: 100%;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 30px;
}

.footer-brand .footer-logo {
  font-size: 2rem;
  font-weight: 900;
  color: #ffffff;
  text-decoration: none;
  display: inline-block;
  margin-bottom: 12px;
}

.footer-brand p {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: 16px;
  max-width: 400px;
}

.footer-age-badge {
  display: inline-block;
  background: var(--color-card-bg);
  border: 1px solid var(--color-gold);
  color: var(--color-gold);
  font-weight: 700;
  padding: 4px 14px;
  border-radius: 4px;
  font-size: 0.9rem;
  margin-bottom: 10px;
}

.footer-column h4 {
  font-size: 1rem;
  color: #ffffff;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-weight: 600;
}

.footer-nav {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-nav li {
  margin-bottom: 10px;
}

.footer-nav a {
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s;
}

.footer-nav a:hover {
  color: var(--color-glow);
}

.footer-bottom {
  border-top: 1px solid var(--color-divider);
  padding-top: 16px;
  max-width: 1200px;
  margin: 0 auto;
}

.footer-bottom p {
  color: var(--color-text-secondary);
  font-size: 0.8rem;
  text-align: center;
  margin: 0;
}

@media (max-width: 768px) {
  :root {
    --header-offset: 108px;
  }

  body {
    overflow-x: hidden;
  }

  .header-container {
    width: 100%;
    max-width: none;
    padding: 0 10%;
    padding-top: 8px;
    padding-bottom: 8px;
    justify-content: space-between;
    gap: 8px;
  }

  .logo {
    font-size: 1.7rem;
    margin-left: auto;
    margin-right: auto;
    order: 2;
  }

  .desktop-nav-buttons {
    display: none;
    order: 1;
  }

  .main-nav {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 80%;
    max-width: 320px;
    height: 100vh;
    height: 100dvh;
    background-color: var(--color-primary);
    box-shadow: 4px 0 30px rgba(0, 0, 0, 0.7);
    z-index: 1000;
    flex-direction: column;
    justify-content: flex-start;
    align-items: stretch;
    padding-top: 70px;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    border-right: 1px solid var(--color-border);
    border-bottom: none;
  }

  .main-nav.active {
    display: flex;
    transform: translateX(0);
  }

  .main-nav.active .nav-container {
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    gap: 4px;
    padding: 16px;
  }

  .nav-container {
    width: 100%;
    max-width: none;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    gap: 4px;
    padding: 12px;
  }

  .nav-container a {
    display: block;
    width: 100%;
    padding: 12px 16px;
    text-align: center;
    font-size: 0.95rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  }

  .mobile-nav-buttons {
    display: flex;
    justify-content: center;
    gap: 8px;
    background: rgba(8, 22, 43, 0.95);
    padding: 8px 12px;
    border-bottom: 1px solid var(--color-divider);
    flex-wrap: nowrap;
    overflow-x: auto;
    width: 100%;
  }

  .mobile-nav-buttons .btn {
    flex: 1 1 auto;
    padding: 8px 12px;
    font-size: 0.8rem;
    min-width: 0;
    width: auto;
    display: inline-flex;
    text-align: center;
    justify-content: center;
    align-items: center;
    white-space: nowrap;
  }

  .mobile-menu-toggle {
    display: flex;
    order: 1;
    min-width: 30px;
  }

  .mobile-menu-toggle.active {
    display: flex;
  }

  .mobile-menu-overlay {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    z-index: 999;
    pointer-events: none;
    opacity: 0;
  }

  .mobile-menu-overlay.active {
    pointer-events: auto;
    opacity: 1;
  }

  .site-header {
    border-bottom: 1px solid var(--color-border);
  }

  .site-footer {
    padding: 30px 16px 15px;
  }

  .footer-container {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .footer-column:nth-child(1) {
    margin-bottom: 10px;
  }

  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }

  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
}

@media (max-width: 480px) {
  .header-container {
    padding: 6px 12px;
  }

  .btn {
    padding: 8px 14px;
    font-size: 0.8rem;
  }

  .main-nav {
    width: 85%;
  }
}

@media (min-width: 1800px) {
  .header-top,
  .main-nav,
  .site-footer {
    font-size: 1rem;
    max-width: 1800px;
    margin-left: auto;
    margin-right: auto;
    border-left: 1px solid var(--color-border);
    border-right: 1px solid var(--color-border);
  }
}
/* 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;
}