change download filename

src/website/pdf.ts

@@ -174,5 +174,5 @@ export async function downloadVocaQuiz(levels: number[], day: number) {
     levels.includes(chunk.level) && chunk.day === day
   ).flatMap((chunk) => chunk.voca_list);
   const bufferPdf = await makePdf(shuffle(voca_list));
-  downloadBuffer(bufferPdf, "voca.pdf");
+  downloadBuffer(bufferPdf, `voca-${day}-${levels.join(",")}.pdf`);
 }