diff --git a/resources/css/main.css b/resources/css/main.css
index 8c09a08..193bc17 100644
--- a/resources/css/main.css
+++ b/resources/css/main.css
@@ -114,6 +114,10 @@ tr:hover {
   margin: auto;
 }
 
+.center canvas {
+  border: 5px solid black;
+}
+
 .inline {
   margin: 15px;
 }
diff --git a/resources/css/scss/_classes.scss b/resources/css/scss/_classes.scss
index ae19d1a..eb31ccd 100644
--- a/resources/css/scss/_classes.scss
+++ b/resources/css/scss/_classes.scss
@@ -10,6 +10,10 @@
     * {
         margin: auto;
     }
+
+    canvas {
+      border: 5px solid black;
+    }
 }
 
 .inline {