/* 页眉样式 */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: var(--color-white);
  box-shadow: var(--shadow-sm);
  z-index: var(--z-header);
}

.main-nav {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 60px;
}

.logo {
  font-size: 24px;
  font-weight: bold;
  color: var(--color-link);
  text-decoration: none;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--gap-xl);
}

.nav-menu a {
  color: var(--color-text-nav);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition-color);
}

.nav-menu a:hover {
  color: var(--color-link);
}

/* 导航下拉菜单 - 仅桌面端 */
@media (min-width: 769px) {
  .nav-has-dropdown {
    position: relative;
  }

  .nav-dropdown {
    display: none;
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    list-style: none;
    margin: 8px 0 0;
    padding: 8px 0;
    background: var(--color-white);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    min-width: 160px;
    z-index: 1000;
  }

  .nav-dropdown::before {
    content: '';
    position: absolute;
    top: -8px;
    left: 0;
    right: 0;
    height: 8px;
  }

  .nav-has-dropdown:hover .nav-dropdown {
    display: block;
  }

  .nav-dropdown li {
    padding: 0;
  }

  .nav-dropdown a {
    display: block;
    padding: 8px 20px;
    font-size: 14px;
    white-space: nowrap;
    transition: var(--transition-normal);
  }

  .nav-dropdown a:hover {
    background: var(--color-primary-10);
  }
}

/* 移动端隐藏下拉菜单 */
@media (max-width: 768px) {
  .nav-dropdown {
    display: none;
  }
}

/* 页脚样式 */
.site-footer {
  background: var(--color-white);
  margin-top: 60px;
  padding: 30px 0;
  border-top: 1px solid var(--color-border-light);
}

.footer-content {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  text-align: center;
  color: var(--color-text-muted);
}

.footer-content p {
  margin: 5px 0;
}

.footer-content a {
  color: var(--color-link);
  text-decoration: none;
}

.footer-content a:hover {
  text-decoration: underline;
}

/* GitHub角标 */
.github-corner:hover .octo-arm {
  animation: octocat-wave 560ms ease-in-out;
}

@keyframes octocat-wave {
  0%, 100% {
    transform: rotate(0);
  }
  20%, 60% {
    transform: rotate(-25deg);
  }
  40%, 80% {
    transform: rotate(10deg);
  }
}

/* 移动端优化 - 平板 */
@media (max-width: 768px) {
  .main-nav {
    padding: 0 70px 0 15px;
  }

  .logo {
    font-size: 20px;
  }

  .nav-menu {
    gap: var(--gap-lg);
    font-size: 14px;
  }
}

/* 移动端优化 - 手机 */
@media (max-width: 480px) {
  /* 隐藏右上角 GitHub 角标 */
  .github-corner {
    display: none;
  }

  .main-nav {
    padding: 0 15px 0 10px;
    height: 50px;
  }

  .logo {
    font-size: 18px;
  }

  .nav-menu {
    gap: var(--gap-sm);
    font-size: 12px;
  }

  .nav-menu li a {
    padding: 4px 6px;
  }

  .site-footer {
    margin-top: 40px;
    padding: 20px 0;
  }

  .footer-content {
    padding: 0 var(--container-padding-tablet);
    font-size: 13px;
  }

  .footer-content p {
    margin: 3px 0;
  }

  .github-corner svg {
    width: 50px;
    height: 50px;
  }
}