Bootstrap Responsive Menu Bar With Light/Dark Mode Source Code

HTML

<html lang="en" >
<head>
  <meta charset="UTF-8">
  <link rel='stylesheet' href='https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css'>
  <link rel="stylesheet" href="./style.css">
 
</head>
<body>
 
<body class="hero-anime">	
 
	<div class="navigation-wrap bg-light start-header start-style">
		<div class="container">
		<div class="row">
		<div class="col-12">
		<nav class="navbar navbar-expand-md navbar-light">
		
		<a class="navbar-brand" href="https://webdevtrick.com/" target="_blank"><img src="https://webdevtrick.com/wp-content/uploads/logo-fb-1.png" alt=""></a>	
		
		<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
		<span class="navbar-toggler-icon"></span>
		</button>
		
		<div class="collapse navbar-collapse" id="navbarSupportedContent">
		<ul class="navbar-nav ml-auto py-4 py-md-0">
		<li class="nav-item pl-4 pl-md-0 ml-0 ml-md-4 active">
		<a class="nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false">Home</a>
		</li>
		<li class="nav-item pl-4 pl-md-0 ml-0 ml-md-4">
		<a class="nav-link" href="#">About</a>
		</li>
		<li class="nav-item pl-4 pl-md-0 ml-0 ml-md-4">
		<a class="nav-link" href="#">Portfolio</a>
		</li>
		<li class="nav-item pl-4 pl-md-0 ml-0 ml-md-4">
		<a class="nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false">Services</a>
		<div class="dropdown-menu">
		<a class="dropdown-item" href="#">Web Design</a>
		<a class="dropdown-item" href="#">Web Development</a>
		<a class="dropdown-item" href="#">SEO</a>
		<a class="dropdown-item" href="#">AI Development</a>
		</div>
		</li>
		<li class="nav-item pl-4 pl-md-0 ml-0 ml-md-4">
		<a class="nav-link" href="#">Blog</a>
		</li>
		<li class="nav-item pl-4 pl-md-0 ml-0 ml-md-4">
		<a class="nav-link" href="#">Contact</a>
		</li>
		</ul>
		</div>
		
		</nav>		
		</div>
		</div>
		</div>
	</div>
	<div class="section full-height">
		<div class="absolute-center">
		<div class="section">
		<div class="container">
		<div class="row">
		<div class="col-12">
		<h1>Bootstrap<br>Menu</h1>
		<p>scroll down for nav animation</p>	
		</div>	
		</div>		
		</div>		
		</div>
		<div class="section mt-5">
		<div class="container">
		<div class="row">
		<div class="col-12">
		<div id="switch">
		<div id="circle"></div>
		</div>
		</div>	
		</div>		
		</div>		
		</div>
		</div>
	</div>
	<div class="my-5 py-5">
	</div>
 
</body>
 
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js'></script>
<script src='https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js'></script>
<script  src="function.js"></script>
 
</body>
</html>

CSS

@import url('https://fonts.googleapis.com/css?family=Poppins:100,100i,200,200i,300,300i,400,400i,500,500i,600,600i,700,700i,800,800i,900,900i&subset=devanagari,latin-ext');
 
body{
    font-family: 'Poppins', sans-serif;
	font-size: 16px;
	line-height: 24px;
	font-weight: 400;
	color: #212112;
	background-size: 7%;
	background-color: #fff;
	overflow-x: hidden;
    transition: all 200ms linear;
}
::selection {
	color: #fff;
	background-color: #ff4242;
}
::-moz-selection {
	color: #fff;
	background-color: #ff4242;
}
.start-header {
	opacity: 1;
	transform: translateY(0);
	padding: 10px 0;
	box-shadow: 0 10px 30px 0 rgb(33,33,33,0.15);
	-webkit-transition : all 0.3s ease-out;
	transition : all 0.3s ease-out;
}
.start-header.scroll-on {
	box-shadow: 0 5px 10px 0 rgb(33,33,33,0.15);
	padding: 5px 0;
	-webkit-transition : all 0.3s ease-out;
	transition : all 0.3s ease-out;
}
.start-header.scroll-on .navbar-brand img{
	height: 28px;
	-webkit-transition : all 0.3s ease-out;
	transition : all 0.3s ease-out;
}
.navigation-wrap{
	position: fixed;
	width: 100%;
	top: 0;
	left: 0;
	z-index: 1000;
	-webkit-transition : all 0.3s ease-out;
	transition : all 0.3s ease-out;
}
.navbar{
	padding: 0;
}
.navbar-brand img{
	height: 52px;
	width: auto;
	display: block;
	-webkit-transition : all 0.3s ease-out;
	transition : all 0.3s ease-out;
}
.navbar-toggler {
	float: right;
	border: none;
	padding-right: 0;
}
.navbar-toggler:active,
.navbar-toggler:focus {
	outline: none;
}
.navbar-light .navbar-toggler-icon {
	width: 24px;
	height: 17px;
	background-image: none;
	position: relative;
	border-bottom: 1px solid #000;
    transition: all 300ms linear;
}
.navbar-light .navbar-toggler-icon:after, 
.navbar-light .navbar-toggler-icon:before{
	width: 24px;
	position: absolute;
	height: 1px;
	background-color: #000;
	top: 0;
	left: 0;
	content: '';
	z-index: 2;
    transition: all 300ms linear;
}
.navbar-light .navbar-toggler-icon:after{
	top: 8px;
}
.navbar-toggler[aria-expanded="true"] .navbar-toggler-icon:after {
	transform: rotate(45deg);
}
.navbar-toggler[aria-expanded="true"] .navbar-toggler-icon:before {
	transform: translateY(8px) rotate(-45deg);
}
.navbar-toggler[aria-expanded="true"] .navbar-toggler-icon {
	border-color: transparent;
}
.nav-link{
	color: #212121 !important;
	font-weight: 500;
    transition: all 200ms linear;
}
.nav-item:hover .nav-link{
	color: #ff4242 !important;
}
.nav-item.active .nav-link{
	color: #777 !important;
}
.nav-link {
	position: relative;
	padding: 5px 0 !important;
	display: inline-block;
}
.nav-item:after{
	position: absolute;
	bottom: -5px;
	left: 0;
	width: 100%;
	height: 2px;
	content: '';
	background-color: #ff4242;
	opacity: 0;
    transition: all 200ms linear;
}
.nav-item:hover:after{
	bottom: 0;
	opacity: 1;
}
.nav-item.active:hover:after{
	opacity: 0;
}
.nav-item{
	position: relative;
    transition: all 200ms linear;
}
 
.bg-light {
	background-color: #fff !important;
    transition: all 200ms linear;
}
.section {
    position: relative;
	width: 100%;
	display: block;
}
.full-height {
    height: 100vh;
}
.over-hide {
    overflow: hidden;
}
.absolute-center {
	position: absolute;
	top: 50%;
	left: 0;
	width: 100%;
  margin-top: 40px;
	transform: translateY(-50%);
	z-index: 20;
}
h1 {
	font-size: 48px;
	line-height: 1.2;
	font-weight: 700;
	color: #212112;
	text-align: center;
}
p {
	text-align: center;
	margin: 0;
	padding-top: 10px;
	opacity: 1;
	transform: translate(0);
    transition: all 300ms linear;
    transition-delay: 1700ms;
}
 
body.hero-anime p{
	opacity: 0;
	transform: translateY(40px);
    transition-delay: 1700ms;
}
#switch,
#circle {
	cursor: pointer;
	-webkit-transition: all 300ms linear;
	transition: all 300ms linear; 
} 
#switch {
	width: 60px;
	height: 8px;
	border: 2px solid #ff4242;
	border-radius: 27px;
	background: #ff4242;
	position: relative;
	display: block;
	margin: 0 auto;
	text-align: center;
	opacity: 1;
	transform: translate(0);
    transition: all 300ms linear;
    transition-delay: 1900ms;
}
body.hero-anime #switch{
	opacity: 0;
	transform: translateY(40px);
    transition-delay: 1900ms;
}
#circle {
	position: absolute;
	top: -11px;
	left: -13px;
	width: 26px;
	height: 26px;
	border-radius: 50%;
	background: #000;
}
.switched {
	border-color: #000 !important;
	background: #ff4242 !important;
}
.switched #circle {
	left: 43px;
	box-shadow: 0 4px 4px rgba(26,53,71,0.25), 0 0 0 1px rgba(26,53,71,0.07);
	background: #fff;
}
.nav-item .dropdown-menu {
    transform: translate3d(0, 10px, 0);
    visibility: hidden;
    opacity: 0;
	max-height: 0;
    display: block;
	padding: 0;
	margin: 0;
    transition: all 200ms linear;
}
.nav-item.show .dropdown-menu {
    opacity: 1;
    visibility: visible;
	max-height: 999px;
    transform: translate3d(0, 0px, 0);
}
.dropdown-menu {
	padding: 10px!important;
	margin: 0;
	font-size: 13px;
	letter-spacing: 1px;
	color: #212121;
	background-color: #fcfaff;
	border: none;
	border-radius: 3px;
	box-shadow: 0 5px 10px 0 rgb(33,33,33,0.15);
    transition: all 200ms linear;
}
.dropdown-toggle::after {
	display: none;
}
 
.dropdown-item {
	padding: 3px 15px;
	color: #212121;
	border-radius: 2px;
    transition: all 200ms linear;
}
.dropdown-item:hover, 
.dropdown-item:focus {
	color: #fff;
	background-color: rgb(255,66,66,0.6);
}
 
body.dark{
	color: #fff;
	background-color: #1f2029;
}
body.dark h1{
	color: #fff;
}
body.dark h1 span{
    transition-delay: 0ms !important;
}
body.dark p{
	color: #fff;
    transition-delay: 0ms !important;
}
body.dark .bg-light {
	background-color: #14151a !important;
}
body.dark .start-header {
	box-shadow: 0 10px 30px 0 rgba(0, 0, 0, 0.15);
}
body.dark .start-header.scroll-on {
	box-shadow: 0 5px 10px 0 rgba(0, 0, 0, 0.15);
}
body.dark .nav-link{
	color: #fff !important;
}
body.dark .nav-item.active .nav-link{
	color: #999 !important;
}
body.dark .dropdown-menu {
	color: #fff;
	background-color: #1f2029;
	box-shadow: 0 5px 10px 0 rgba(0, 0, 0, 0.25);
}
body.dark .dropdown-item {
	color: #fff;
}
body.dark .navbar-light .navbar-toggler-icon {
	border-bottom: 1px solid #fff;
}
body.dark .navbar-light .navbar-toggler-icon:after, 
body.dark .navbar-light .navbar-toggler-icon:before{
	background-color: #fff;
}
body.dark .navbar-toggler[aria-expanded="true"] .navbar-toggler-icon {
	border-color: transparent;
}
 
 
@media (max-width: 767px) { 
	h1{
		font-size: 38px;
	}
	.nav-item:after{
		display: none;
	}
	.nav-item::before {
		position: absolute;
		display: block;
		top: 15px;
		left: 0;
		width: 11px;
		height: 1px;
		content: "";
		border: none;
		background-color: #000;
		vertical-align: 0;
	}
	.dropdown-toggle::after {
		position: absolute;
		display: block;
		top: 10px;
		left: -23px;
		width: 1px;
		height: 11px;
		content: "";
		border: none;
		background-color: #000;
		vertical-align: 0;
		transition: all 200ms linear;
	}
	.dropdown-toggle[aria-expanded="true"]::after{
		transform: rotate(90deg);
		opacity: 0;
	}
	.dropdown-menu {
		padding: 0 !important;
		background-color: transparent;
		box-shadow: none;
		transition: all 200ms linear;
	}
	.dropdown-toggle[aria-expanded="true"] + .dropdown-menu {
		margin-top: 10px !important;
		margin-bottom: 20px !important;
	}
	body.dark .nav-item::before {
		background-color: #fff;
	}
	body.dark .dropdown-toggle::after {
		background-color: #fff;
	}
	body.dark .dropdown-menu {
		background-color: transparent;
		box-shadow: none;
	}
}

JS

(function($) { "use strict";
 
	$(function() {
		var header = $(".start-style");
		$(window).scroll(function() {    
		var scroll = $(window).scrollTop();
		
		if (scroll >= 10) {
		header.removeClass('start-style').addClass("scroll-on");
		} else {
		header.removeClass("scroll-on").addClass('start-style');
		}
		});
	});		
		
	//Animation
	
	$(document).ready(function() {
		$('body.hero-anime').removeClass('hero-anime');
	});
 
	//Menu On Hover
		
	$('body').on('mouseenter mouseleave','.nav-item',function(e){
		if ($(window).width() > 750) {
		var _d=$(e.target).closest('.nav-item');_d.addClass('show');
		setTimeout(function(){
		_d[_d.is(':hover')?'addClass':'removeClass']('show');
		},1);
		}
	});	
	
	//Switch light/dark
	
	$("#switch").on('click', function () {
		if ($("body").hasClass("dark")) {
		$("body").removeClass("dark");
		$("#switch").removeClass("switched");
		}
		else {
		$("body").addClass("dark");
		$("#switch").addClass("switched");
		}
	});  
	
  })(jQuery);