font weight unification

scss/_variables.scss

@@ -278,7 +278,7 @@ $input-focus-color: inherit !default;
 
 //buttons
 $btn-padding-x: 1rem !default;
-$btn-font-weight: 500 !default;
+$btn-font-weight: $font-weight-bold !default;
 $btn-border-radius: 3px !default;
 
 //cards
@@ -387,7 +387,7 @@ $navbar-brand-padding-y: $nav-link-padding-y !default;
 $navbar-brand-image-height: 2rem !default;
 $navbar-brand-margin-right: 0 !default;
 $navbar-brand-font-size: $h3-font-size !default;
-$navbar-brand-font-weight: 500 !default;
+$navbar-brand-font-weight: $font-weight-bold !default;
 
 $navbar-toggler-font-size: 1rem !default;
 $navbar-toggler-padding-x: 0 !default;

scss/ui/_buttons.scss

 .btn {
-  font-weight: 500;
+  font-weight: $btn-font-weight;
   display: inline-flex;
   align-items: center;
   justify-content: center;

scss/ui/_forms.scss

@@ -127,7 +127,7 @@ Form help
  */
 .form-help {
   display: inline-flex;
-  font-weight: 600;
+  font-weight: $font-weight-bold;
   align-items: center;
   justify-content: center;
   width: 1.125rem;