@media (max-width: 900px) {
  .brand img { 
    height: 48px; 
  }
  
  .brand-name {
    font-size: 20px; 
  }

  .main-nav a {
    font-size: 16px;
  }
}


@media (max-width: 640px) {
  .header-inner {
    flex-wrap: wrap; 
    gap: 10px; 
  }
  
  .site-header {
    margin-top: 20px;
  }
  
  .main-nav {
    width: 100%; 
    margin-left: 0; 
    margin-bottom: 20px; 
  }
  
  .main-nav ul {
    flex-wrap: wrap;
    gap: 12px 18px;
    justify-content: space-between;
  }

  .main-nav li {
    flex: 1 1 45%;
    text-align: center;
  }

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

  .poem-author {
    font-size: 20px;
  }

  .poem-text {
    font-size: 18px;
  }

  .poem-detail-container {
    max-width: 100%;
  }
}