chore: small changes

src/DevTools/NavBar.js

@@ -91,7 +91,7 @@ export default class NavBar extends Emitter {
     const $el = this._$el
 
     $el.css({
-      height: height + 1
+      height: height + 2
     })
     $el.find('.eruda-nav-bar-item').css({
       height: height,

src/DevTools/NavBar.scss

@@ -8,6 +8,7 @@ $item-width: 69px;
   .nav-bar {
     @include absolute(100%, $height);
     @include overflow-auto(x);
+    border-top: 1px solid var(--border);
     border-bottom: 1px solid var(--border);
     z-index: 100;
     background: var(--darker-background);