.drop-zone {
      border: 2px dashed var(--border-color);
      padding: 40px;
      text-align: center;
      cursor: pointer;
      border-radius: 12px;
      transition: all 0.3s;
      margin-bottom: 24px;
      background: var(--card-bg);
      color: var(--text-color);
    }
.drop-zone.dragover {
      border-color: var(--primary-color);
      background-color: var(--hover-bg);
    }
.controls {
      margin-bottom: 20px;
    }
.control-group {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      margin-bottom: 12px;
      gap: 12px;
    }
.control-group label {
      margin-right: 4px;
      font-weight: bold;
    }
.button {
      padding: 10px 20px;
      background-color: var(--primary-color);
      color: var(--accent-ink);
      border: none;
      border-radius: 6px;
      font-size: 16px;
      cursor: pointer;
      transition: opacity 0.2s;
    }
.button:hover {
      opacity: 0.9;
    }
.preview-area {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }
.preview-container {
      border: 1px solid var(--border-color);
      border-radius: 8px;
      padding: 10px;
      box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
      text-align: center;
      background-color: #fff;
      
      transition: background-color 0.3s;
    }
.preview-container img {
      max-width: 200px;
      display: block;
      margin: 0 auto 8px auto;
    }
.step-box {
      background: var(--card-bg);
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 2rem;
      margin-bottom: 2rem;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    }
h2, p {
      color: var(--text-color);
    }
.tool-container {
      max-width: 900px;
      margin: 0 auto;
      padding: 20px;
    }

select { max-width: 100%; min-width: 0; }
@media (max-width: 480px) { #pngFormatSelect, #resizeMode { display: block; width: 100%; margin-top: 4px; } }