replace font-family declarations with mixins

.gitignore

@@ -2,3 +2,4 @@
 /vendor
 package-lock.json
 composer.lock
+*.css.map

sass/mixins/_mixins-master.scss

@@ -1,7 +1,8 @@
 @mixin font-1($weight) {
   // see functions.php->google_fonts()
   // and functions.php->_s_scripts()
-  font-family: "Montserrat", sans-serif;
+  font-family: "Montserrat", -apple-system, BlinkMacSystemFont, "Segoe UI",
+    Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
   @if $weight == regular {
     font-weight: 400;
   } @else if $weight == bold {

sass/typography/_copy.scss

@@ -19,7 +19,7 @@ address {
 
 pre {
   background: $color__background-pre;
-	font-family: $font__pre;
+  @include font-pre;
   font-size: 0.9375rem;
   line-height: $font__line-height-pre;
   margin-bottom: 1.6em;
@@ -32,7 +32,7 @@ code,
 kbd,
 tt,
 var {
-	font-family: $font__code;
+  @include font-code;
   font-size: 0.9375rem;
 }