style: spacing 토큰 추가

Author: jwj0620gcu

src/app/styles/index.css

@@ -72,6 +72,7 @@
   --spacing-xs: 12px;
   --spacing-xxs: 10px;
   --spacing-xxxs: 8px;
+  --spacing-xxxxs: 4px;
 
   /* Margin (Primitive/Scale) */
   --margin-l: 24px;