/* ============================================================
   页脚样式
   ============================================================ */

footer {
  background: radial-gradient(circle at 20% 20%, rgba(77, 208, 225, 0.12), transparent 55%),
              linear-gradient(135deg, #061737, #0b1e3d 65%, #002d5e);
  color: var(--color-white);
  padding: var(--spacing-2xl) var(--container-padding);
  margin-top: var(--spacing-2xl);
}

.footer-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

.footer-section h3 {
  color: var(--color-white);
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-base);
  border-bottom: 2px solid rgba(255, 152, 0, 0.6);
  padding-bottom: var(--spacing-sm);
  letter-spacing: 0.05em;
}

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

.footer-section li {
  margin-bottom: var(--spacing-sm);
}

.footer-section a {
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-section a:hover {
  color: var(--color-secondary);
  text-decoration: underline;
}

.footer-section p {
  color: rgba(230, 239, 249, 0.85);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-base);
}

/* 页脚底部 */
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: var(--spacing-lg);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-base);
}

.footer-copyright {
  color: var(--color-gray-light);
  font-size: var(--font-size-sm);
}

.footer-social {
  display: flex;
  gap: var(--spacing-base);
}

.footer-social-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: var(--border-radius-full);
  color: var(--color-white);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.footer-social-link:hover {
  background: linear-gradient(135deg, var(--color-secondary), var(--color-primary));
  transform: translateY(-3px);
}

/* 响应式设计 */
@media (max-width: 1024px) {
  .footer-content {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
  }
}

@media (max-width: 768px) {
  footer {
    padding: var(--spacing-lg) var(--container-padding);
  }

  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .footer-social {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  footer {
    padding: var(--spacing-base) var(--container-padding);
  }

  .footer-section h3 {
    font-size: var(--font-size-base);
  }

  .footer-copyright {
    font-size: var(--font-size-xs);
  }
}