Follow the CSS Style Guide rules for including a space after the property colon.

app/assets/stylesheets/framework/common.scss

@@ -8,20 +8,20 @@
 /** COMMON CLASSES **/
 .prepend-top-0 { margin-top: 0; }
 .prepend-top-5 { margin-top: 5px; }
-.prepend-top-10 { margin-top:10px }
+.prepend-top-10 { margin-top: 10px }
 .prepend-top-default { margin-top: $gl-padding !important; }
-.prepend-top-20 { margin-top:20px }
-.prepend-left-10 { margin-left:10px }
+.prepend-top-20 { margin-top: 20px }
+.prepend-left-10 { margin-left: 10px }
 .prepend-left-default { margin-left: $gl-padding; }
-.prepend-left-20 { margin-left:20px }
+.prepend-left-20 { margin-left: 20px }
 .append-right-5 { margin-right: 5px }
-.append-right-10 { margin-right:10px }
+.append-right-10 { margin-right: 10px }
 .append-right-default { margin-right: $gl-padding; }
-.append-right-20 { margin-right:20px }
-.append-bottom-0 { margin-bottom:0 }
-.append-bottom-10 { margin-bottom:10px }
-.append-bottom-15 { margin-bottom:15px }
-.append-bottom-20 { margin-bottom:20px }
+.append-right-20 { margin-right: 20px }
+.append-bottom-0 { margin-bottom: 0 }
+.append-bottom-10 { margin-bottom: 10px }
+.append-bottom-15 { margin-bottom: 15px }
+.append-bottom-20 { margin-bottom: 20px }
 .append-bottom-default { margin-bottom: $gl-padding; }
 .inline { display: inline-block }
 .center { text-align: center }
@@ -134,10 +134,10 @@ p.time {
 
 // Fix issue with notes & lists creating a bunch of bottom borders.
 li.note {
-  img { max-width:100% }
+  img { max-width: 100% }
   .note-title {
     li {
-      border-bottom:none !important;
+      border-bottom: none !important;
     }
   }
 }

app/assets/stylesheets/framework/variables.scss

@@ -27,7 +27,7 @@ $gl-gray: #5a5a5a;
 $gl-padding: 16px;
 $gl-btn-padding: 10px;
 $gl-vert-padding: 6px;
-$gl-padding-top:10px;
+$gl-padding-top: 10px;
 $gl-avatar-size: 40px;
 $secondary-text: #7f8fa4;
 $error-exclamation-point: #e62958;

app/assets/stylesheets/pages/appearances.scss

@@ -4,7 +4,7 @@
 }
 
 .appearance-light-logo-preview {
-  background-color:  $background-color;
+  background-color: $background-color;
   max-width: 72px;
   padding: 10px;
   margin-bottom: 10px;

app/assets/stylesheets/pages/dashboard.scss

@@ -11,15 +11,15 @@
 }
 
 .dashboard-search-filter {
-  padding:5px;
+  padding: 5px;
 
   .search-text-input {
-    float:left;
+    float: left;
     @extend .col-md-2;
   }
   .btn {
     margin-left: 5px;
-    float:left;
+    float: left;
   }
 }
 

app/assets/stylesheets/pages/events.scss

@@ -94,7 +94,7 @@
     }
   }
 
-  &:last-child { border:none }
+  &:last-child { border: none }
 
   .event_commits {
     li {
@@ -138,7 +138,7 @@
     @include str-truncated(100%);
     padding: 5px 0;
     font-size: 13px;
-    float:left;
+    float: left;
     margin-right: -150px;
     padding-right: 150px;
     line-height: 20px;

app/assets/stylesheets/pages/issuable.scss

@@ -59,7 +59,7 @@
 .issuable-sidebar {
   .block {
     @include clearfix;
-    padding:  $gl-padding 0;
+    padding: $gl-padding 0;
     border-bottom: 1px solid $border-gray-light;
     // This prevents the mess when resizing the sidebar
     // of elements repositioning themselves..

app/assets/stylesheets/pages/login.scss

@@ -28,7 +28,7 @@
 
     img {
       max-width: 100%;
-      margin-bottom:  30px;
+      margin-bottom: 30px;
     }
 
     a {
@@ -85,7 +85,7 @@
 
     &.middle {
       border-top: 0;
-      margin-bottom:0;
+      margin-bottom: 0;
       @include border-radius(0);
     }
 

app/assets/stylesheets/pages/notes.scss

@@ -3,9 +3,9 @@
  */
 
 @-webkit-keyframes targe3-note {
-  from { background:#fffff0; }
-  50% { background:#ffffd3; }
-  to { background:#fffff0; }
+  from { background: #fffff0; }
+  50% { background: #ffffd3; }
+  to { background: #fffff0; }
 }
 
 ul.notes {
@@ -93,12 +93,12 @@ ul.notes {
   .discussion {
     overflow: hidden;
     display: block;
-    position:relative;
+    position: relative;
   }
 
   .note {
     display: block;
-    position:relative;
+    position: relative;
 
     .note-body {
       overflow: auto;

app/assets/stylesheets/pages/projects.scss

@@ -286,11 +286,11 @@ table.table.protected-branches-list tr.no-border {
   padding-bottom: 4px;
 
   ul.nav {
-    display:inline-block;
+    display: inline-block;
   }
 
   .nav li {
-    display:inline;
+    display: inline;
   }
 
   .nav > li > a {
@@ -303,11 +303,11 @@ table.table.protected-branches-list tr.no-border {
   }
 
   li {
-    display:inline;
+    display: inline;
   }
 
   a {
-    float:left;
+    float: left;
     font-size: 17px;
   }
 

app/assets/stylesheets/pages/tree.scss

@@ -46,7 +46,7 @@
 
       img {
         position: relative;
-        top:-1px;
+        top: -1px;
       }
     }