convert to CSS variables

frontend/src/app/components/transaction/transaction-preview.component.scss

@@ -54,7 +54,7 @@
   }
 
   .label {
-    color: #ffffff66;
+    color: var(--transparent-fg);
   }
 
   &.pair > *:first-child {
@@ -79,7 +79,7 @@
 
 .graph-wrapper {
   position: relative;
-  background: #181b2d;
+  background: var(--stat-box-bg);
   padding: 10px 0;
   padding-bottom: 0;
 

frontend/src/app/components/transaction/transaction.component.scss

@@ -70,11 +70,11 @@
 }
 
 .arrow-green {
-	color: #1a9436;
+	color: var(--success);
 }
 
 .arrow-red {
-	color: #dc3545;
+	color: var(--red);
 }
 
 .container-xl {
@@ -100,7 +100,7 @@
 .graph-container {
   position: relative;
   width: 100%;
-  background: #181b2d;
+  background: var(--stat-box-bg);
   padding: 10px 0;
   padding-bottom: 0;
 }