Wider export dialog (#603)

src/components/ExportDialog.tsx

@@ -259,7 +259,7 @@ export function ExportDialog({
       />
       {modalIsShown && (
         <Modal
-          maxWidth={640}
+          maxWidth={800}
           onCloseRequest={handleClose}
           labelledBy="export-title"
         >

src/components/Modal.css

@@ -26,4 +26,5 @@
   position: relative;
   z-index: 2;
   width: 100%;
+  max-width: 100%;
 }