Fix pozadí u 'side-line'

static/main.css

@@ -201,6 +201,7 @@ canvas {
   box-sizing: border-box;
   border: solid 0.125vw var(--color-primary);
   border-radius: 0.125vw;
+  background-color: var(--color-primary);
 }
 .number-thing {
   display: flex;