body{margin:0;font-family:system-ui;background:#fafafa;color:#222}
header{padding:2rem;background:linear-gradient(135deg,#007bff,#00b4ff);color:#fff;text-align:center}
.drop-zone{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:200px;border:3px dashed #007bff;border-radius:12px;margin:2rem;transition:.3s}
.drop-zone.hover{border-color:#00b4ff;background:#e6f4ff}
.preview{margin:2rem}
.hidden{display:none}
.download-btn{display:block;margin:0 auto 2rem auto;padding:1rem 2rem;background:#28a745;color:#fff;border:none;border-radius:30px;font-size:1.1rem;cursor:pointer}