#1: use $space SCSS vars

Author: brendanfalkowski

css/src/_modal.scss

@@ -41,8 +41,8 @@ $z-modal-dialog:   901 !default;
 .modal_dialog {
     position: absolute;
     z-index: $z-modal-dialog;
-    right: 15px;
-    left: 15px;
+    right: $space-base;
+    left: $space-base;
     border-radius: $radius-base;
     background: #FFF;
     box-shadow: 0 5px 15px 5px black(0.2);
@@ -83,8 +83,8 @@ $z-modal-dialog:   901 !default;
 @media (min-width: 600px) {
 
     .modal_dialog {
-        right: 25px;
-        left: 25px;
+        right: $space-xl;
+        left: $space-xl;
     }
 
 }