window.downloadFile = function (fileName, base64, mimeType) {
    const byteChars = atob(base64);
    const bytes = new Uint8Array(byteChars.length);
    for (let i = 0; i < byteChars.length; i++) bytes[i] = byteChars.charCodeAt(i);
    const blob = new Blob([bytes], { type: mimeType });
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = fileName;
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    setTimeout(() => URL.revokeObjectURL(url), 10000);
};