Add SASS variables for colors

assets/sass/_task_summary.sass

@@ -1,14 +1,13 @@
+@import variables
+
 #task-summary
   margin-bottom: 15px
   h2
-    color: #666
-    font-size: $text-xlarge
+    color: color('medium')
+    font-size: size('xlarge')
     margin-top: 0
     padding-top: 0
 
-.task-summary-buttons
-  margin-top: 10px
-
 .task-summary-container
   border: 2px solid #000
   border-radius: 8px
@@ -23,9 +22,9 @@
   justify-content: space-between
 
 .task-summary-column
-  color: #666
+  color: color('primary')
   span
-    color: #555
+    color: color('medium')
   li
     line-height: 23px
 
@@ -34,6 +33,6 @@
   border-radius: 8px
   margin-bottom: 20px
   h2
-    color: #555
+    color: color('medium')
     margin: 0
     padding: 8px