refactor(theme/Nav): remove menu margin compensation

Author: SoonIter

packages/core/src/theme/components/Nav/NavMenu.scss

@@ -5,8 +5,6 @@
   align-items: center;
   height: 100%;
   list-style: none;
-  margin: 0 calc(0px - var(--rp-nav-menu-item-padding-x)) 0
-    calc(0px - var(--rp-nav-menu-item-padding-x));
 
   @media (max-width: 1279px) {
     --rp-nav-menu-item-padding-x: 12px;