ui: 完善全部下载按钮的样式和位置

src/components/DownloadAll.tsx

@@ -28,8 +28,16 @@ export function DownloadAll() {
   };
 
   return (
-    <button className="btn btn-primary" onClick={onClickDownloadAll}>
-      Download All
+    <button
+      style={{ width: '48px', height: '48px', paddingInline: '0px', margin: '10px', marginLeft: 'auto' }}
+      className="btn btn-primary"
+      onClick={onClickDownloadAll}
+      title="下载全部"
+    >
+      <svg xmlns="http://www.w3.org/2000/svg" height="40px" viewBox="0 0 24 24" width="40px" fill="#e3e3e3">
+        <path d="M0 0h24v24H0z" fill="none" />
+        <path d="M19 9h-4V3H9v6H5l7 7 7-7zM5 18v2h14v-2H5z" />
+      </svg>
     </button>
   );
 }