.app {
      width: 100%;
      max-width: 480px;
      margin: 0 auto;
      height: calc(var(--vh) * 100);
      background: #ffffff;
      display: flex;
      flex-direction: column;
    }

    .app-header {
      padding: 12px 16px;
      text-align: center;
      border-bottom: 1px solid #eee;
      background: #ffffff;
    }

    .app-header-title {
      font-weight: 600;
      font-size: 16px;
      margin-bottom: 2px;
    }

    .app-header-subtitle {
      font-size: 13px;
      color: #777;
    }

    .app-chat {
      flex: 1 1 auto;
      min-height: 0;
      padding: 12px 16px;
      overflow-y: auto;
      display: flex;
      flex-direction: column;
      gap: 6px;
      background: #ffffff;
    }

    .app-bubble {
      display: inline-block;
      max-width: 80%;
      padding: 8px 13px;
      border-radius: 18px;
      font-size: 14px;
      line-height: 1.4;
      opacity: 0;
      transform: translateY(8px);
      animation: fadeInUp 0.25s forwards;
    }

    .app-bubble.left {
      align-self: flex-start;
      background: #f1f1f5;
      border-bottom-left-radius: 4px;
    }

    .app-bubble.right {
      align-self: flex-end;
      background: #f3e6ff;
      border-bottom-right-radius: 4px;
    }

    @keyframes fadeInUp {
      to { opacity: 1; transform: translateY(0); }
    }

    .app-footer {
      padding: 10px 16px 16px;
      border-top: 1px solid #eee;
      background: #ffffff;
    }

    .app-btn {
      width: 100%;
      border: none;
      border-radius: 999px;
      padding: 12px 16px;
      font-size: 15px;
      font-weight: 600;
      background: #ff4b79;
      color: #ffffff;
      cursor: pointer;
    }

    .app-btn:active { transform: scale(0.97); }

    .app-answer-form {
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .app-answer-input {
      flex: 1;
      padding: 9px 13px;
      border-radius: 999px;
      border: 1px solid #ddd;
      font-size: 16px;
      outline: none;
    }

    .app-answer-input:focus { border-color: #ff4b79; }

    .app-answer-form .btn {
      flex: 0 0 80px;
      padding-inline: 8px;
      font-size: 14px;
    }