diff --git a/css/chess.css b/css/chess.css
index f481adf..729a040 100644
--- a/css/chess.css
+++ b/css/chess.css
@@ -1,3 +1,7 @@
+*, ::before, ::after {
+   box-sizing: border-box;
+}
+
 body {
    font-family: 'Roboto', sans-serif;
    padding: 0;