fix: font family polyfill (#111)

Author: Innei

src/client/styles/main.css

@@ -2,7 +2,7 @@
 
 html {
   /* --at-apply: font-sans; */
-  font-family: 'Roboto';
+  font-family: 'Roboto', system-ui;
   overflow-y: scroll;
   overscroll-behavior: none;
   -ms-overflow-style: none;
@@ -16,7 +16,7 @@ body::-webkit-scrollbar {
 }
 
 body {
-  font-family: 'Roboto';
+  font-family: 'Roboto', system-ui;
   /* trap scroll inside iframe */
   /* height: calc(100vh + 1px); */
 }