/* 页脚 */
.site-footer {
  background: #2c3e50;
  color: white;
  padding: 60px 0 30px;
  margin-top: 60px;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 40px;
  margin-bottom: 40px;
}

@media (max-width: 992px) {
  .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .footer-content {
    grid-template-columns: 1fr;
  }
}

.footer-column h4 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 20px;
  color: white;
}

.footer-links {
  list-style: none;
}

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

.footer-links a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  font-size: 14px;
  transition: var(--transition);
}

.footer-links a:hover {
  color: white;
  padding-left: 5px;
}

.footer-bottom {
  text-align: center;
  padding-top: 30px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 14px;
  color: rgba(255, 255, 255, 0.6);
}

/* 返回顶部按钮 */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: var(--secondary-color);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: #2980b9;
  transform: translateY(-5px);
}

/* 响应式调整 */
@media (max-width: 768px) {
  .article-header {
    padding: 30px 20px 15px;
  }

  .article-title {
    font-size: 24px;
  }

  .article-content {
    padding: 30px 20px;
  }

  .article-actions {
    padding: 15px 20px;
    flex-direction: column;
    gap: 15px;
  }

  .comments-section {
    padding: 30px 20px;
  }

  .header-content {
    flex-direction: column;
    height: auto;
    padding: 15px 0;
    gap: 15px;
  }

  .nav-links {
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* 暗色主题支持 */
@media (prefers-color-scheme: dark) {
  :root {
    --primary-color: #ecf0f1;
    --secondary-color: #3498db;
    --text-color: #ecf0f1;
    --light-text: #bdc3c7;
    --border-color: #34495e;
    --bg-color: #2c3e50;
    --light-bg: #34495e;
  }

  body {
    background: var(--bg-color);
  }
}