Vertically center hamburger button

app/assets/stylesheets/new_nav.scss

@@ -375,8 +375,6 @@ header.navbar-gitlab-new {
   display: flex;
   width: 100%;
   position: relative;
-  padding-top: $gl-padding;
-  padding-bottom: $gl-padding;
   align-items: center;
   border-bottom: 1px solid $border-color;
 }
@@ -390,7 +388,6 @@ header.navbar-gitlab-new {
 
   @media (max-width: $screen-xs-max) {
     padding-left: 17px;
-    margin-left: 33px;
     border-left: 1px solid $gl-text-color-quaternary;
   }
 

app/assets/stylesheets/new_sidebar.scss

@@ -440,7 +440,7 @@ $new-sidebar-collapsed-width: 50px;
   background-color: transparent;
   border: 0;
   padding: 6px 16px;
-  margin: 0 16px 0 -15px;
+  margin: 0 0 0 -15px;
   height: 46px;
 
   i {
@@ -449,9 +449,8 @@ $new-sidebar-collapsed-width: 50px;
   }
 
   @media (max-width: $screen-xs-max) {
-    display: inline-block;
-    position: absolute;
-    top: 2px;
+    display: flex;
+    align-items: center;
 
     i {
       font-size: 18px;