diff --git a/less/header.less b/less/header.less
index 78e494d..c5f8ce8 100644
--- a/less/header.less
+++ b/less/header.less
@@ -17,7 +17,7 @@ header {
     font-size: @font-size-h5;
     color: @navbar-default-link-color;
     .border-radius;
-    margin-right: @grid-gutter-width/2;
+    margin-right: (@grid-gutter-width/2);
 
     &:hover {
       color: @navbar-default-link-color;
@@ -48,7 +48,7 @@ header {
         display: inline-block;
         a {
           display: block;
-          padding: @grid-gutter-width/4 @grid-gutter-width/2;
+          padding: (@grid-gutter-width/4) (@grid-gutter-width/2);
           border: 1px solid #fff;
          // line-height: @navbar-height - (@navbar-padding-horizontal*2);
         }
@@ -56,7 +56,7 @@ header {
 
       /* override bootstrap */
       &.navbar-nav > li > a {
-        padding: @grid-gutter-width/4 @grid-gutter-width/2;
+        padding: (@grid-gutter-width/4) (@grid-gutter-width/2);
       }
     }
   }
diff --git a/less/homepage.less b/less/homepage.less
index 255b32c..3980e83 100644
--- a/less/homepage.less
+++ b/less/homepage.less
@@ -2,7 +2,7 @@
   .jumbotron;
   .wrapper;
   padding: @grid-gutter-width !important;
-  margin-bottom: @grid-gutter-width/2;
+  margin-bottom: (@grid-gutter-width / 2);
 
   a[role="button"] {
     .btn;
@@ -11,7 +11,7 @@
   }
   img {
     float: right;
-    margin-left: @grid-gutter-width/2;
+    margin-left: (@grid-gutter-width / 2);
   }
 
   @media (max-width: @screen-sm-max) {
diff --git a/less/order-form.less b/less/order-form.less
index 1b348c6..3129b87 100644
--- a/less/order-form.less
+++ b/less/order-form.less
@@ -59,13 +59,13 @@
   .text-shadow;
   
   .background {
-    padding: @grid-gutter-width/2;
+    padding: (@grid-gutter-width/2);
     background-color: rgba(0,0,0,.6);
     .black-gradient;
   }
 }
 .tab-pane {
-  padding: @grid-gutter-width/2;
+  padding: (@grid-gutter-width/2);
 }
 .nav.nav-tabs {
   height: 42px;
diff --git a/less/restaurants.less b/less/restaurants.less
index f4e49ca..56393d0 100644
--- a/less/restaurants.less
+++ b/less/restaurants.less
@@ -1,14 +1,14 @@
 .restaurant {
   .border;
-  padding: @grid-gutter-width/2;
-  margin-bottom: @grid-gutter-width/2;
+  padding: (@grid-gutter-width/2);
+  margin-bottom: (@grid-gutter-width/2);
   
   h3, h2 {
     margin-top: 0;
   }
   img {
     float: left;
-    margin-right: @grid-gutter-width/2;
+    margin-right: (@grid-gutter-width/2);
     .border;
   }
   .address {
@@ -80,12 +80,12 @@
 @media (max-width: @screen-sm-max) {
 
   .restaurants, h2.page-header, .restaurant-content {
-    padding-left: @grid-gutter-width/2;
-    padding-right: @grid-gutter-width/2;
+    padding-left: (@grid-gutter-width/2);
+    padding-right: (@grid-gutter-width/2);
   }
   .restaurant, h2.page-header {
-    margin-left: -@grid-gutter-width/2;
-    margin-right: -@grid-gutter-width/2;
+    margin-left: (-@grid-gutter-width/2);
+    margin-right: (-@grid-gutter-width/2);
   }
 
 }
\ No newline at end of file
diff --git a/package.json b/package.json
index 30baf68..be2c832 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,6 @@
     }
   },
   "devDependencies": {
-    "less": "^3.9.0"
+    "less": "^4.1.1"
   }
 }