*{box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,sans-serif;max-width:600px;margin:0 auto;padding:20px;background:#f5f5f5;color:#333}#app{background:#fff;padding:24px;border-radius:8px;box-shadow:0 2px 8px #0000001a}h1{margin-top:0;font-size:1.5rem;color:#222;text-align:center}h2{font-size:1.1rem;margin-bottom:12px}#upload-section{margin-bottom:16px}#upload-section label{display:block;margin-bottom:8px;font-weight:500;text-align:center}input[type=file]{width:100%;padding:8px;border:2px dashed #ccc;border-radius:4px;cursor:pointer}input[type=file]:hover{border-color:#999}#status{padding:10px;border-radius:4px;margin-bottom:16px;min-height:20px}#status:empty{display:none}#status.success{background:#e8f5e9;color:#2e7d32}#status.error{background:#ffebee;color:#c62828}#tracks-section{border-top:1px solid #eee;padding-top:16px}#tracks-list{max-height:300px;overflow-y:auto;margin-bottom:16px;border:1px solid #eee;border-radius:4px}.track-item{display:flex;align-items:center;padding:12px;border-bottom:1px solid #eee}.track-item:last-child{border-bottom:none}.track-item:hover{background:#f9f9f9}.track-item input[type=checkbox]{width:18px;height:18px;margin-right:12px;cursor:pointer}.track-item label{flex:1;cursor:pointer;display:flex;flex-direction:column;gap:2px}.track-name{font-weight:500}.track-instrument{font-size:.85rem;color:#666}#export-controls{display:flex;gap:8px;flex-wrap:wrap}button{padding:10px 16px;border:none;border-radius:4px;cursor:pointer;font-size:.9rem;transition:background .2s}#select-all,#deselect-all{background:#e0e0e0;color:#333}#select-all:hover,#deselect-all:hover{background:#d0d0d0}#export-midi{background:#1976d2;color:#fff;flex:1;min-width:150px}#export-midi:hover:not(:disabled){background:#1565c0}#export-midi:disabled{background:#bdbdbd;cursor:not-allowed}footer{text-align:center;padding:10px}footer a{color:#000}