Hamburger menu - background color delay (bootstrap4)

Question

I started coding a couple of months ago and i'm almost done with a basic portfolio site.

The issue I can't work out is the hamburger menu background. I've managed to give the menu a background colour with CSS, but when clicking on it, the menu doesn't change to that colour straight away. There's a very short delay but it frustrates me a little!

Apologies if any of the code is messy. Any constructive criticism is welcome!

Link: https://codepen.io/MikeyT24/pen/xrQvxe

HTML

<nav class="navbar fixed-top navbar-inverse navbar-toggleable-sm opaque-navbar">
  <div class="container containernav">
    <button class="navbar-toggler " type="button" data-toggle="collapse" data-target="#myContent" aria-controls="myContent" aria-expanded="false" aria-label="toggle navigation">
    <span class="navbar-toggler-icon"></span>
    </button>
    <h1 class="navbar-brand m-0 ">Michael Treeves</h1>
  <div class="collapse navbar-collapse" id="myContent">
  <div class="navbar-nav ml-auto">
    <a class="nav-item nav-link" href="#about">About</a>
    <a class="nav-item nav-link" href="#portfolio">Portfolio</a>
    <a class="nav-item nav-link" href="#contact">Contact</a>
  </div> <!--navbar-nav-->
  </div> <!--collapse-->
  </div> <!--container-->
</nav>

CSS

/***********************************************************
  OPAQUE NAVBAR SECTION
**********************************************************/
.opaque-navbar {
    background-color: rgba(0,0,0,0);
    height: 50px;
    border-bottom: 0px;
    transition: background-color 0.5s ease 0s;
}

.opaque-navbar.opaque {
    background-color: rgba(100,100,150,0.9);
    height: 50px;
    transition: background-color 0.5s ease 0s;
}

@media (max-width: 992px) {
  .opaque-navbar {
    height: 50px;
    transition: background-color .5s ease 0s;
}

@media (max-width: 768px){
.collapse {
    background-color: rgba(100,100,150,0.9);
}

Script (not sure if relevant)

  * OPAQUE NAVBAR SCRIPT
  **********************************************************
  */

  // Toggle tranparent navbar when the user scrolls the page

  $(window).scroll(function() {
    if($(this).scrollTop() > 650)  /*height in pixels when the navbar becomes non opaque*/
    {
        $('.opaque-navbar').addClass('opaque');
    } else {
        $('.opaque-navbar').removeClass('opaque');
    }
});

Many thanks!

Mike.

Answer 1

While opening navbar bootstrap changes .collapse class to .collapsing and then .collapse that's why background applying after few seconds.

Use .navbar-collapse instead.

.navbar-collapse {
    background-color: rgba(100,100,150,0.9);
}