headings unify, borders unify (#1254)

src/scss/layout/_root.scss

@@ -18,6 +18,18 @@
   --#{$prefix}icon-color: #{$icon-color};
   --#{$prefix}disabled-bg: #{$disabled-bg};
 
+  @each $name, $value in $font-weights {
+    --#{$prefix}font-weight-#{$name}: #{$value};
+  }
+
+  @each $name, $value in $font-sizes {
+    --#{$prefix}font-size-#{$name}: #{$value};
+  }
+
+  @each $name, $value in $line-heights {
+    --#{$prefix}line-height-#{$name}: #{$value};
+  }
+
   @each $name, $value in $shadows {
     --#{$prefix}#{$name}: #{$value};
   }