/* 追加スタイル */
.checkerboard {
  background-image: linear-gradient(45deg, #e2e8f0 25%, transparent 25%),
    linear-gradient(-45deg, #e2e8f0 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #e2e8f0 75%),
    linear-gradient(-45deg, transparent 75%, #e2e8f0 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0;
}

.file-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 10px;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 6px;
}

.preview-page {
  border: 1px solid #cbd5e1;
  background: white;
  padding: 8px;
  border-radius: 8px;
}