Update app.css

app.css

@@ -1,3 +1,29 @@
+body {
+background-color: #f0f0f2;
+margin: 0;
+padding: 0;
+font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
+
+}
+div {
+width: 600px;
+margin: 5em auto;
+padding: 2em;
+background-color: #fdfdff;
+border-radius: 0.5em;
+box-shadow: 2px 3px 7px 2px rgba(0,0,0,0.02);
+}
+a:link, a:visited {
+color: #38488f;
+text-decoration: none;
+}
+@media (max-width: 700px) {
+div {
+margin: 0 auto;
+width: auto;
+}
+}
+
 body{overflow:hidden;overscroll-behavior:none;/*background-color:#f0f0f2;*/background: white repeating-linear-gradient( 45deg, #EEE, #EEE 5px, #FFF 5px, #FFF 10px );margin:0;padding:0;font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif}
 article{width:600px;margin: 5em auto;padding:2em;background-color:#fdfdff;border-radius:0.5em;box-shadow: 2px 3px 7px 2px rgba(0,0,0,0.02)}
 a:link, a:visited{color:#38488f;text-decoration:none}