diff --git a/src/App.css b/src/App.css
index 066680d..28425e9 100644
--- a/src/App.css
+++ b/src/App.css
@@ -1,3 +1,13 @@
+* {
+  box-sizing: border-box;
+}
+
+body {
+  font-family: sans-serif;
+  margin: 20px;
+  padding: 0;
+}
+
 .square {
   background: #fff;
   border: 1px solid #999;