Add main styles in style.css for layout and design consistency

Author: moses77-boop

Form-Controls/style.css

@@ -16,4 +16,11 @@ body{
     color: var(--color-text);
     font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
     line-height: 1.5;
+}
+main{
+    min-width: 32rem;
+    margin: 0 auto;
+    background: var(--color-border);
+    border-radius: var(--radius);
+    padding: 2rem;
 }