move .gap style to base

app/assets/stylesheets/common/base/topic-post.scss

@@ -197,3 +197,40 @@ blockquote > *:first-child {
 blockquote > *:last-child {
   margin-bottom: 0 !important;
 }
+
+.gap {
+  background-color: dark-light-diff($primary, $secondary, 90%, -60%);
+  padding: 5px 0;
+  color: lighten($primary, 70%);
+  cursor: pointer;
+  text-align: center;
+  width: calc(#{$topic-avatar-width} + #{$topic-body-width} + 2 * #{$topic-body-width-padding});
+
+  &.jagged-border {
+    background-image:
+    linear-gradient(
+                    135deg,
+                    $secondary 50%, rgba(255,255,255,0) 50%
+    ),
+    linear-gradient(
+                    -135deg,
+                    $secondary 50%, rgba(255,255,255,0) 50%
+    ),
+    linear-gradient(
+                    45deg,
+                    $secondary 50%, rgba(255,255,255,0) 50%
+    ),
+    linear-gradient(
+                    -45deg,
+                    $secondary 50%, rgba(255,255,255,0) 50%
+    );
+    background-position:
+    top center, top center,
+    bottom center, bottom center;
+    background-size: .9em .9em;
+    background-repeat: repeat-x;
+    padding: 20px 0;
+    margin-bottom: 20px;
+  }
+
+}

app/assets/stylesheets/desktop/topic-post.scss

@@ -709,43 +709,6 @@ $topic-avatar-width: 45px;
   z-index: 2;
 }
 
-.gap {
-  background-color: dark-light-diff($primary, $secondary, 90%, -60%);
-  padding: 5px 0;
-  color: lighten($primary, 30%);
-  cursor: pointer;
-  text-align: center;
-  width: calc(#{$topic-avatar-width} + #{$topic-body-width} + 2 * #{$topic-body-width-padding});
-
-  &.jagged-border {
-    background-image:
-    linear-gradient(
-                    135deg,
-                    $secondary 50%, rgba(255,255,255,0) 50%
-    ),
-    linear-gradient(
-                    -135deg,
-                    $secondary 50%, rgba(255,255,255,0) 50%
-    ),
-    linear-gradient(
-                    45deg,
-                    $secondary 50%, rgba(255,255,255,0) 50%
-    ),
-    linear-gradient(
-                    -45deg,
-                    $secondary 50%, rgba(255,255,255,0) 50%
-    );
-    background-position:
-    top center, top center,
-    bottom center, bottom center;
-    background-size: .9em .9em;
-    background-repeat: repeat-x;
-    padding: 20px 0;
-    margin-bottom: 20px;
-  }
-
-}
-
 .time-gap {
   width: 755px;
   border-top: 1px solid dark-light-diff($primary, $secondary, 90%, -60%);

app/assets/stylesheets/mobile/topic-post.scss

@@ -1,9 +1,5 @@
 .gap {
-  background-color: dark-light-diff($primary, $secondary, 90%, -60%);
+  /* may not need this */
-  padding: 5px 15px;
-  color: $primary;
-  text-align: center;
-  margin: 10px 0;
 }
 
 .time-gap {