Factor behaviors.scss constants

app/assets/stylesheets/behaviors.scss

 // Details
 //--------
-.js-details-container .content { display: none; }
-.js-details-container .content.hide { display: block; }
-.js-details-container.open .content { display: block; }
-.js-details-container.open .content.hide { display: none; }
+.js-details-container {
+  .content {
+    display: none;
+    &.hide { display: block; }
+  }
+  &.open .content {
+    display: block;
+    &.hide { display: none; }
+  }
+}
 
 // Toggle between two states.
-.js-toggler-container .turn-on  { display: block; }
-.js-toggler-container .turn-off { display: none; }
-.js-toggler-container.on .turn-on  { display: none; }
-.js-toggler-container.on .turn-off { display: block; }
+.js-toggler-container {
+  .turn-on  { display: block; }
+  .turn-off { display: none; }
+  &.on {
+    .turn-on  { display: none; }
+    .turn-off { display: block; }
+  }
+}