use variable font size for header

Author: LukaHarambasic

assets/scss/_settings.scss

@@ -28,7 +28,7 @@ $fs-s:  $s-s;
 $fs:    $s;
 $fs-m:  $s-m;
 $fs-l:  $s-l;
-$fs-xl: $s-xl;
+$fs-xl: $s-xl * 2;
 
 /*
 * Colors

components/LhCvHeader.vue

@@ -38,7 +38,7 @@
 
     h1 {
       color: $c-primary;
-      font-size: 4rem;
+      font-size: $fs-xl;
       margin: $s 0 0 $s-xl;
       width: 100%;
       line-height: 1;