update navbar toggle btn (#572)

Author: Arhell

_layouts/bootstrap.html

@@ -66,10 +66,7 @@
         <div class="container-fluid">
             <div class="navbar-header">
                 <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
-                    <span class="sr-only">Toggle navigation</span>
-                    <span class="icon-bar"></span>
-                    <span class="icon-bar"></span>
-                    <span class="icon-bar"></span>
+                  <i class="fa fa-bars" aria-hidden="true"></i>
                 </button>
                 <a href="/" class="navbar-brand main-logo">
                   <svg width="81" height="60" style="vertical-align: middle" viewBox="0 0 81 60" fill="none" xmlns="http://www.w3.org/2000/svg">

_scss/_main.scss

@@ -699,10 +699,6 @@ body {
   }
 }
 
-body .navbar-inverse .navbar-toggle .icon-bar {
-  background-color: #000;
-}
-
 @media screen and (min-width: 1030px) {
   .navbar-collapse.collapse {
     position: relative;
@@ -1251,6 +1247,16 @@ body .panel-info > .panel-heading {
 
 .navbar-toggle {
   margin-right: 0;
+  width: 44px;
+  height: 34px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0;
+  .fa {
+    font-size: 20px;
+    color: #333333;
+  }
 
   &:hover {
     background-color: #dddddd !important;