Update: remove alternative background variable added for a future feature.

resources/css/common.css

@@ -10,7 +10,6 @@
     --ls-primary-background-color: #002b36;
     --ls-secondary-background-color: #073642;
     --ls-tertiary-background-color: #0f4552;
-    --ls-alternative-background-color: #01313d;
 
     --ls-block-properties-background-color: #02222a;
     --ls-search-background-color: var(--ls-primary-background-color);
@@ -53,7 +52,6 @@
     --ls-primary-background-color: white;
     --ls-secondary-background-color: #D8E1E8;
     --ls-tertiary-background-color: #f0f8ff;
-    --ls-alternative-background-color: #ced9e0;
 
 
     --ls-block-properties-background-color: var(--ls-tertiary-background-color);