Refactor(css): sass fixes

Author: rarestoma

src/assets/scss/core/_dropdown.scss

@@ -1,3 +1,5 @@
+@use "sass:math";
+
 // Menus https://www.google.com/design/spec/components/menus.html#menus-specs
 // Dropdown buttons (mobile and desktop) https://www.google.com/design/spec/components/buttons.html#buttons-dropdown-buttons
 
@@ -90,7 +92,7 @@
     text-decoration: none;
 
     font-size: .8125rem;
-    border-radius: $border-radius / 2;
+    border-radius: math.div($border-radius, 2);
     margin: 0 $bmd-dropdown-margin-y;
     @include transitions($fast-transition-time, $transition-linear);
 

src/assets/scss/core/_togglebutton.scss

@@ -1,3 +1,5 @@
+@use "sass:math";
+
 .togglebutton {
   vertical-align: middle;
   &, label, input, .toggle {
@@ -70,15 +72,15 @@
     // set bg when checked
     input[type=checkbox]:checked {
       + .toggle {
-        background-color: rgba($brand-primary, (70/100)); // Switch bg on
+        background-color: rgba($brand-primary, (math.div(70,100))); // Switch bg on
       }
 
       + .toggle:after {
         border-color: $brand-primary; // Handle on
       }
 
       + .toggle:active:after {
-        box-shadow: 0 1px 3px 1px rgba(0, 0, 0, 0.4), 0 0 0 15px rgba($brand-primary, (10/100)); // Ripple on
+        box-shadow: 0 1px 3px 1px rgba(0, 0, 0, 0.4), 0 0 0 15px rgba($brand-primary, (math.div(10,100))); // Ripple on
       }
     }
   }