css fix

frontend/src/routes/project/KanbanCard.svelte

@@ -5,7 +5,7 @@
         if (!task.tags || !tag_colors) return '';
         for (let tag of task.tags){
             let color = tag_colors[tag.toLowerCase()];
-            if (color) return `background: ${color}`;
+            if (color) return `background-color: ${color}`;
         }
         return '';
     }