/* 响应式设计 */
@media (max-width: 768px) {
  .upload-area {
    padding: 20px 0;
  }

  .card#uploadSection {
    padding: 15px;
  }

  .container {
    padding-left: 15px;
    padding-right: 15px;
  }

  header h1 {
    font-size: 1.8rem;
  }

  header p {
    font-size: 0.9rem;
  }

  header .theme-toggle {
    top: 45px;
    right: 15px;
  }

  .theme-toggle .theme-btn,
  .back-btn {
    width: 35px;
    height: 35px;
  }

  .back-btn {
    top: 45px;
  }

  .card {
    border-style: none;
  }

  .card h2 {
    font-size: 1.2rem;
  }

  .stat-number {
    font-size: 1.4rem;
  }

  .dashboard {
    grid-template-columns: minmax(0, 1fr);
  }

  .something-container {
    border-style: none;
    padding-right: 0;
  }

  .like-container {
    grid-template-columns: minmax(0, 1fr);
  }

  .favorites-container {
    border-top: 2px solid var(--border-primary);
    padding-top: 3px;
  }

  .conversation-item .favorite-btn {
    font-size: 1.4rem;
  }

  .controls {
    flex-direction: column;
    gap: 0;
  }

  .controls :nth-child(2) {
    border-top-style: none;
    border-bottom-style: none;
  }

  .search-box,
  .filter-select {
    padding: 9px;
    width: 100%;
    border-radius: 0;
    font-size: 0.9rem;
  }

  .conversation-header {
    display: none;
  }

  .list-container {
    min-height: 80vh;
    max-height: 100vh;
  }

  .messages-container {
    min-height: 0;
    max-height: 100vh;
  }

  .conversation-item {
    border-radius: 0;
    margin-bottom: 0;
    border-top-width: 1px;
    border-bottom-width: 1px;
  }

  .conversation-item:first-child {
    border-top-width: 2px;
  }

  .conversation-item:last-child {
    border-bottom-width: 2px;
  }

  .conversation-title {
    font-size: 0.9rem;
  }

  .conversation-meta {
    font-size: 0.8rem;
  }

  .message {
    margin-bottom: 10px;
    padding: 5px;
  }

  .message.user {
    margin-left: 5%;
  }

  .message.assistant {
    margin-right: 5%;
  }
}