body { font-family: sans-serif; text-align: center; padding: 20px; background: #f4f4f9; }
        .card { background: white; padding: 25px; border-radius: 15px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); display: inline-block; width: 340px; }
        #status { margin-top: 15px; font-size: 13px; color: #666; min-height: 40px; border-top: 1px solid #eee; padding-top: 15px; }
        button { background: #28a745; color: white; border: none; padding: 15px; border-radius: 8px; cursor: pointer; width: 100%; font-weight: bold; margin-top: 10px; }
        button:disabled { background: #ccc; }
        #preview { width: 100%; max-height: 250px; object-fit: contain; border: 1px dashed #ccc; margin-top: 10px; display: none; }
        canvas { display: none; }