Move all hex colors in SASS to variables and all variations to darken/lighten

app/assets/stylesheets/tables.scss

@@ -9,13 +9,13 @@
     padding: 8px;
     line-height: 18px;
     vertical-align: top;
-    border-top: 1px solid #282c37;
+    border-top: 1px solid $color1;
     text-align: left;
   }
 
   & > thead > tr > th {
     vertical-align: bottom;
-    border-bottom: 2px solid #282c37;
+    border-bottom: 2px solid $color1;
     border-top: 0;
     font-weight: 500;
   }
@@ -25,11 +25,11 @@
   }
 
   & > tbody > tr:nth-child(odd) > td, & > tbody > tr:nth-child(odd) > th {
-    background: lighten(#1a1c23, 2%);
+    background: $color1;
   }
 
   a {
-    color: #2b90d9;
+    color: $color4;
     text-decoration: underline;
 
     &:hover {
@@ -51,11 +51,11 @@ a.table-action-link {
   display: inline-block;
   margin-right: 5px;
   padding: 0 10px;
-  color: rgba(255, 255, 255, 0.7);
+  color: rgba($color5, 0.7);
   font-weight: 500;
 
   &:hover {
-    color: #fff;
+    color: $color5;
   }
 
   i.fa {