diff --git a/src/index.css b/src/index.css
index bd5bd6d..36abd35 100644
--- a/src/index.css
+++ b/src/index.css
@@ -1,13 +1,19 @@
-body {
-  margin: 0;
-  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
-    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
-    sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-}
-
-code {
-  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
-    monospace;
-}
+*,
+*::before,
+*::after {
+  box-sizing: border-box;
+}
+
+body {
+  margin: 0;
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
+    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
+    sans-serif;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+code {
+  font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New",
+    monospace;
+}