Studio: refactoring font-weight CSS rules to use Sass placeholders

common/static/sass/_mixins-inherited.scss

@@ -121,10 +121,10 @@
 @mixin button {
   @include font-size(14);
   @include transition(background-color 0.15s, box-shadow 0.15s);
+  @extend %t-strong;
   box-shadow: 0 1px 0 rgba(255, 255, 255, .3) inset, 0 0 0 rgba(0, 0, 0, 0);
   display: inline-block;
   padding: ($baseline/5) $baseline ($baseline/4);
-  font-weight: 700;
 
   &.disabled, &.is-disabled {
     border: 1px solid $gray-l1 !important;
@@ -331,9 +331,9 @@
   }
 
   h5 {
+    @extend %t-strong;
     margin-bottom: 8px;
     color: #fff;
-    font-weight: 700;
   }
 
   .row {
@@ -388,9 +388,9 @@
     .draft-item:after,
     .public-item:after,
     .private-item:after {
+      @extend %t-strong;
       margin-left: 3px;
       font-size: 9px;
-      font-weight: 600;
       text-transform: uppercase;
     }
 

common/static/sass/_mixins.scss

@@ -182,11 +182,11 @@
 %ui-btn-primary {
   @extend %ui-btn;
   @extend %ui-btn-pill;
+  @extend %t-strong;
   padding:($baseline/2) $baseline;
   border-width: 1px;
   border-style: solid;
   box-shadow: none;
-  font-weight: 600;
   line-height: 1.5em;
   text-align: center;
 
@@ -224,9 +224,9 @@
 }
 
 %ui-btn-flat-outline {
-  @extend %t-action4;
   @include transition(all .15s);
-  font-weight: 600;
+  @extend %t-strong;
+  @extend %t-action4;
   text-align: center;
   border-radius: ($baseline/4);
   border: 1px solid $blue-l2;