Develop Reference

Sidebar not opening when clicking on hamburger button

I wrote code on JavaScript, it suppose to give class "active" to the sidebar when clicking on the hamburger menu, but it isn't. It says that "hamburger is not defined or it's not a function". I checked everything I could but could not find the answer.
Here is the HTML code:
const hamburger = document.getElementsByClassName(".hamburger");
const sidebar = document.getElementsByClassName(".sidebar");
hamburger.addEventListener('click', () => {
sidebar.classList.add("active");
})
.main-page {
width: 100%;
height: 100vh;
background-color: #000;
display: flex;
flex-direction: column;
justify-content: center;
}
.main-page__inner {
width: 100%;
max-width: 1350px;
margin: 0 auto;
}
.main-page__title {
font-family: 'Syncopate';
font-style: normal;
font-weight: 700;
font-size: 100px;
line-height: 104px;
color: #FFFFFF;
}
.hamburger {
position: absolute;
width: 40px;
top: 69px;
left: 41px;
z-index: 9999;
padding: 15px 0;
cursor: pointer;
}
.hamburger__item {
width: 100%;
display: block;
height: 4px;
background-color: #fff;
position: absolute;
inset: 0;
margin: 0 auto;
}
.hamburger__item:before,
.hamburger__item:after {
width: 100%;
height: 4px;
position: absolute;
content: "";
background-color: #fff;
left: 0;
z-index: 9999;
}
.hamburger__item:before {
top: -7px;
}
.hamburger__item:after {
bottom: -8px;
}
.sidebar {
position: fixed;
top: 0;
left: -100%;
bottom: 0;
z-index: 600;
background: #591753;
width: 100%;
max-width: 400px;
height: 100vh;
visibility: hidden;
}
.sidebar.open {
visibility: visible;
left: 0;
}
.sidebar__inner {
display: flex;
align-items: center;
justify-content: center;
margin: auto 0;
}
.sidebar__title {
font-family: 'Montserrat';
font-weight: 400;
font-size: 20px;
color: #fff;
}
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link href="https://fonts.googleapis.com/css2?family=Inter:wght#100;200;300;400;500;600;700;800;900&family=Montserrat:wght#400;600&family=Open+Sans:wght#300;400;500;600;700;800&family=Raleway:wght#100;200;300;400;500;600;700;800;900&family=Source+Sans+Pro:wght#600&family=Syncopate:wght#400;700&display=swap"
rel="stylesheet">
<header class="header">
<div class="container">
<div class="header__inner">
<div class="nav-bar">
<img class="logo" src="/assets/Header/LOGO.png" alt="logo">
<a class="click-to-action" href="#">Оставить заявку</a>
</div>
</div>
</div>
</header>
<div class="hamburger" id="hamburger">
<span class="hamburger__item" id="hamburger__item"></span>
</div>
<div class="sidebar" id="sidebar">
<div class="sidebar__inner">
<h1 class="sidebar__title">BLA BLA BLA</h1>
</div>
</div>
<div class="main-page">
<div class="container">
<div class="main-page__inner">
<h1 class="main-page__title">CHAMPION ASTANA</h1>
</div>
</div>
</div>

Will be easier for you if you use
document.getElementById("hamburger"); and
document.getElementById("sidebar");
instead of getElementsByClassName
Also you need to change in the css this class
.sidebar.open {
visibility: visible;
left: 0;
}
into this one:
.sidebar.active {
visibility: visible;
left: 0;
}
Because you are adding the class "active" in sidebar.classList.add("active");, not the class "open".
Here is a working code of your example:
const hamburger = document.getElementById("hamburger");
const sidebar = document.getElementById("sidebar");
hamburger.addEventListener('click', () => {
sidebar.classList.add("active");
})
.main-page {
width: 100%;
height: 100vh;
background-color: #000;
display: flex;
flex-direction: column;
justify-content: center;
}
.main-page__inner {
width: 100%;
max-width: 1350px;
margin: 0 auto;
}
.main-page__title {
font-family: 'Syncopate';
font-style: normal;
font-weight: 700;
font-size: 100px;
line-height: 104px;
color: #FFFFFF;
}
.hamburger {
position: absolute;
width: 40px;
top: 69px;
left: 41px;
z-index: 9999;
padding: 15px 0;
cursor: pointer;
}
.hamburger__item {
width: 100%;
display: block;
height: 4px;
background-color: #fff;
position: absolute;
inset: 0;
margin: 0 auto;
}
.hamburger__item:before,
.hamburger__item:after {
width: 100%;
height: 4px;
position: absolute;
content: "";
background-color: #fff;
left: 0;
z-index: 9999;
}
.hamburger__item:before {
top: -7px;
}
.hamburger__item:after {
bottom: -8px;
}
.sidebar {
position: fixed;
top: 0;
left: -100%;
bottom: 0;
z-index: 600;
background: #591753;
width: 100%;
max-width: 400px;
height: 100vh;
visibility: hidden;
}
.sidebar.active {
visibility: visible;
left: 0;
}
.sidebar__inner {
display: flex;
align-items: center;
justify-content: center;
margin: auto 0;
}
.sidebar__title {
font-family: 'Montserrat';
font-wei
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="ChampionA.css">
<script src="ChampionA.js"></script>
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link href="https://fonts.googleapis.com/css2?family=Inter:wght#100;200;300;400;500;600;700;800;900&family=Montserrat:wght#400;600&family=Open+Sans:wght#300;400;500;600;700;800&family=Raleway:wght#100;200;300;400;500;600;700;800;900&family=Source+Sans+Pro:wght#600&family=Syncopate:wght#400;700&display=swap" rel="stylesheet">
<title>CHAMPION Astana</title>
</head>
<body>
<header class="header">
<div class="container">
<div class="header__inner">
<div class="nav-bar">
<img class="logo" src="/assets/Header/LOGO.png" alt="logo">
<a class="click-to-action" href="#">Оставить заявку</a>
</div>
</div>
</div>
</header>
<div class="hamburger" id="hamburger">
<span class="hamburger__item" id="hamburger__item"></span>
</div>
<div class="sidebar" id="sidebar">
<div class="sidebar__inner">
<h1 class="sidebar__title">BLA BLA BLA</h1>
</div>
</div>
<div class="main-page">
<div class="container">
<div class="main-page__inner">
<h1 class="main-page__title">CHAMPION ASTANA</h1>
</div>
</div>
</div>
</body>
</html>

Firstly you are using getElementsByClassName with wrong string. It should be only the class name: document.getElementsByClassName('hamburger').
Secondly getElementsByClassName returns the array of elements, therefore it should be used like document.getElementsByClassName('hamburger')[0]
I would recommend using document.getElementById("hamburger") as you do have id available.
const hamburger = document.getElementsByClassName("hamburger")[0];
const sidebar = document.getElementsByClassName("sidebar")[0];
hamburger.addEventListener('click', () =>{
sidebar.classList.add("active");
})

When a user scroll down, how I can make the down arrow in the first view disappear?

I want to make the down arrow icons disappear when a user scroll down the page. Although I searched it on another question of stackoverflow, I cannot find a solution. I made jQuery code. I am not sure it is correct or not.
this is the code on fiddle
https://jsfiddle.net/92mtjzew/
main.js
$(document).ready(() => {
$('#slideshow .slick').slick({
autoplay: true,
autoplaySpeed: 2000,
dots: true,
});
});
$(document).ready(() => {
$('#userReview .slick').slick({
autoplayhttps://jsfiddle.net/92mtjzew/#: true,
autoplaySpeed: 8000,
dots: true,
});
});
$(window).scroll(function(){
if($(".box").toggle($(this).scrollTop() === 0) || ($(this).scrollTop() > 0)) {
$('.box').show();
} else {
$('.box').hide();
}
});
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Tutorial</title>
<link rel="stylesheet" type="text/css" href="css/style.css">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="css/font-awesome.min.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.9.0/slick.min.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.9.0/slick-theme.min.css">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
</head>
<body>
<div id="header">
<div class="logo">
<h1><img src="img/logo.png" widht="473px" height="50px"></h1>
</div>
<div class="nav">
<label for="toggle">☰</label>
<input type="checkbox" id="toggle" />
<div class="menu">
Work
About Us
Services
Blog
<span>Contact Us</span>
</div>
</div>
</div><!-- /#header -->
<section id="slideshow">
<div class="slick">
<div><img src="img/image1.jpg" width="1274px" height="640px" alt=""></div>
<div><img src="img/image2.jpg" width="1274px" height="640px" alt=""></div>
<div><img src="img/image3.jpg" width="1274px" height="640px" alt=""></div>
</div>
</section>
<div class="box">
<span onclick="scrollDown()"></span>
<span onclick="scrollDown()"></span>
<span onclick="scrollDown()"></span>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.9.0/slick.min.js"></script>
<script src="js/main.js"></script>
<script>
function scrollDown(){
var businessPage = document.getElementById("businessPage");
businessPage.scrollIntoView();
}
</script>
</body>
</html>
style.css
#media only screen and (max-width: 2000px) {
html, body {
width: 100%;
height: 100%;
margin: 0;
background: linear-gradient(#FBDA61, #FF3CAC);
overflow-x: hidden;
color: cornsilk;
}
a {
text-decoration: none;
}
h1 {
font-size: 26pt;
}
button {
text-transform: uppercase;
font-weight: bold;
}
html {
font-family: "helvetica neue", sans-serif;
}
.box {
position: absolute;
top: 94%;
left: 50%;
transform: translate(-50%, -50%);
z-index: 1;
display: fixed
}
.box span {
display: fixed;
width: 20px;
height: 20px;
border-bottom: 3px solid white;
border-right: 3px solid white;
transform: rotate(45deg);
margin: -10px;
transition: all .3s;
position: absolute;
top: 50%;
left: 50%;
overflow: hidden;
z-index: 1;
animation: animate 2s infinite;
}
.box span:after {
content: '';
position: absolute;
bottom: 0;
left: 0;
width: 100%;
height: 100%;
background-color: white;
z-index: -2;
}
.box span:before {
content: '';
color: cornsilk;
position: absolute;
bottom: 0;
left: 0;
width: 0%;
height: 100%;
background-color: #d3d3d3;
transition: all .3s;
z-index: -1;
}
.box span:hover {
color: #fff;
}
.box span:hover:before {
width: 100%;
}
.box span:nth-child(1) {
opacity: 0.3;
z-index: 1;
}
.box span:nth-child(2) {
opacity: 0.5;
z-index: 1;
}
.logo h1 {
margin: 0px
}
.logo img{
text-align: left;
float: left;
padding: 15px 0 0 0;
}
.nav {
border-bottom: 1px solid #EAEAEB;
text-align: right;
height: 80px;
line-height: 70px;
background-color: black;
}
.menu {
margin: 0 30px 0 0;
}
.menu a {
clear: right;
text-decoration: none;
color: cornsilk;
margin: 0 10px;
line-height: 70px;
}
span {
color: #54D17A;
}
label {
margin: 0 40px 0 0;
font-size: 26px;
display: none;
float: right;
color: cornsilk;
}
#toggle {
display: none;
}
#slideshow {
position: relative;
top: 0px;
left: 0px;
}
#slideshow {
div {
width: 100%;
height: 300px;
img {
width: 100%;
height: auto;
}
}
}

Try the following example
.hidden{display:none !important;}
$(document).ready(function(){
var scroll_pos = 0;
$(document).scroll(function() {
scroll_pos = $(this).scrollTop();
if(scroll_pos > 210) {
$('.box').removeClass("hidden");
} else {
$('.box').addClass("hidden");
}
});
});

On click div moves down

I want to make something like - When I press on About, so there will show overlay over the main div with text about. Now when I click, so that div will show, but it will move down that particles-js div. And I don't want to move that div, but I want to make about to show over that particle (fullscreen overlay with 50% opacity)
$(".about").click(function() {
$(".main").fadeToggle('500');
$(".aboutText").fadeToggle('500');
});
#import url('https://fonts.googleapis.com/css?family=Open+Sans:400,800');
body {
background: #1d1d1d;
font-family: 'Montserrat', sans-serif;
font-size: 100%;
margin: 0 auto;
padding: 0;
overflow-x: hidden;
}
.container {
width: 100%;
margin: 0 auto;
padding: 0;
}
#particles-js {
height: 100vh;
width: 100%;
background-color: green;
}
#about {
height: 100vh;
background-color: beige;
}
h1.main {
color: white;
position: absolute;
padding: 0;
margin: 0 auto;
top: 50%;
display: inline-block;
left: 50%;
text-align: center;
font-size: 4.5em;
transform: translate(-50%, -50%);
}
h2 {
color: white;
position: absolute;
top: 60%;
left: 5%;
font-size: 2em;
}
a.logo {
text-decoration: none;
color: #2ecc71;
}
span.home {
position: absolute;
top: 50%;
right: 1%;
transform: rotate(90deg);
color: #fff;
font-size: 1em;
}
a.about {
position: absolute;
top: 50%;
left: 1%;
transform: rotate(270deg);
color: #fff;
font-size: 1em;
}
a.about {
text-decoration: none;
color: #fff;
}
#media only screen and (max-width: 500px) {
.site-nav a {
padding: 2em;
font-size: 1.5em;
}
}
.text {
color: #fff;
position: relative;
top: 50%;
left: 10%;
background-color: #000;
display: none;
}
a.about:hover {
color: #2ecc71;
}
.aboutText {
background-color: #000;
width: 100%;
height: 100vh;
background-size: cover;
opacity: 0.5;
position: relative;
display: none;
}
.aboutText--open {
background-color: #000;
width: 100%;
height: 100vh;
background-size: cover;
opacity: 0.5;
position: relative;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta charset="UTF-8">
<meta name="description" content="Doplniť neskôr">
</head>
<link rel="stylesheet" href="style.css">
<link rel="stylesheet" href="normalize.css">
<body>
<div class="aboutText">
<div class="text">
<p>sssss</p>
</div>
</div>
<div id="particles-js">
<h1 class="main">Text</h1>
</div>
<span class="home">Home</span>
About
<div id="about">
</div>
<div id="portfolio"></div>
<div id="contact"></div>
<script src="https://code.jquery.com/jquery-3.3.1.js" integrity="sha256-2Kok7MbOyxpgUVvAk/HJ2jigOSYS2auK4Pfzbm7uH60=" crossorigin="anonymous"></script>
<script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script>
<script src="js/particles.js"></script>
<script src="app.js"></script>
</body>
</html>

Is this what you are trying to do? Show the about text when clicked?
$(".about").click(function() {
$("#particles-js").toggleClass("hide")
$(".aboutText").toggleClass("hide")
});
#import url('https://fonts.googleapis.com/css?family=Open+Sans:400,800');
body {
background: #1d1d1d;
font-family: 'Montserrat', sans-serif;
font-size: 100%;
margin: 0 auto;
padding: 0;
overflow-x: hidden;
}
.container {
width: 100%;
margin: 0 auto;
padding: 0;
}
#particles-js {
height: 100vh;
width: 100%;
background-color: green;
}
#about {
height: 100vh;
background-color: beige;
}
h1.main {
color: white;
position: absolute;
padding: 0;
margin: 0 auto;
top: 50%;
display: inline-block;
left: 50%;
text-align: center;
font-size: 4.5em;
transform: translate(-50%, -50%);
}
h2 {
color: white;
position: absolute;
top: 60%;
left: 5%;
font-size: 2em;
}
a.logo {
text-decoration: none;
color: #2ecc71;
}
span.home {
position: absolute;
top: 50%;
right: 1%;
transform: rotate(90deg);
color: #fff;
font-size: 1em;
}
a.about {
position: absolute;
top: 50%;
left: 1%;
transform: rotate(270deg);
color: #fff;
font-size: 1em;
}
a.about {
text-decoration: none;
color: #fff;
}
#media only screen and (max-width: 500px) {
.site-nav a {
padding: 2em;
font-size: 1.5em;
}
}
.text {
color: #fff;
position: relative;
top: 50%;
left: 10%;
background-color: #000;
}
a.about:hover {
color: #2ecc71;
}
.aboutText {
background-color: #000;
width: 100%;
height: 100vh;
background-size: cover;
opacity: 0.5;
position: relative;
}
.hide {
display: none;
}
.aboutText--open {
background-color: #000;
width: 100%;
height: 100vh;
background-size: cover;
opacity: 0.5;
position: relative;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta charset="UTF-8">
<meta name="description" content="Doplniť neskôr">
</head>
<link rel="stylesheet" href="style.css">
<link rel="stylesheet" href="normalize.css">
<body>
<div class="aboutText hide">
<div class="text">
<p>sssss</p>
</div>
</div>
<div id="particles-js">
<h1 class="main">Text</h1>
</div>
<span class="home">Home</span>
About
<div id="about">
</div>
<div id="portfolio"></div>
<div id="contact"></div>
<script src="https://code.jquery.com/jquery-3.3.1.js" integrity="sha256-2Kok7MbOyxpgUVvAk/HJ2jigOSYS2auK4Pfzbm7uH60=" crossorigin="anonymous"></script>
<script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script>
<script src="js/particles.js"></script>
<script src="app.js"></script>
</body>
</html>

MenuBar problems showing css html

Hello I have some problems on showing my menu bar when I am looking it from laptop or other devices and I was wondering if someone can help me! The problem is whenever I scroll down to the slideshow or where is the video my menu bar disappear behind the slideshow or the video. I think you will understand it perfectly when you try it.
<!--JavaScript-->
<script type="text/javascript" src="https://code.jquery.com/jquery-3.2.1.js"></script>
<script type="text/javascript">
$(window).on('scroll', function() {
if ($(window).scrollTop()) {
$('nav').addClass('black');
} else {
$('nav').removeClass('black');
}
});
function toggleMenu(x) {
x.classList.toggle('openMenu');
}
</script>
* {
margin: 0;
padding: 0;
box-sizing: inherit;
}
body {
font: 15px/1.5 Arial, Helvetica, sans-serif;
box-sizing: border-box;
}
/*Menu Bar*/
nav {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 80px;
padding: 0 100px;
transition: all 300ms;
}
nav.black {
background: rgba(0, 0, 0, 0.8);
}
nav .logo {
display: inline-block;
width: 25%;
padding: 0 5px;
line-height: 80px;
font-size: 24px;
transition: all 0.3s;
text-align: center;
}
nav.black .logo {
color: #fff;
}
nav a {
display: inline-block;
width: 12.5%;
line-height: 80px;
color: #151515;
padding: 0 5px;
text-decoration: none;
text-transform: uppercase;
transition: .3s;
text-align: center;
vertical-align: top;
}
nav.black a {
color: #fefefe;
}
nav a:focus {
outline: none;
}
nav a.active {
background: #E2472F;
color: #fff;
border-radius: 6px;
}
section.sec1 {
width: 100%;
height: 100vh;
background: url(img/lol.jpg);
background-size: cover;
background-position: center;
}
/* Hamburger icon */
.hamburger {
display: none;
cursor: pointer;
}
.hamburger .bar1,
.hamburger .bar2,
.hamburger .bar3 {
width: 35px;
height: 5px;
background-color: #fefefe;
margin: 6px 0;
transition: all 0.4s;
}
.openMenu .hamburger .bar1 {
-webkit-transform: rotate(-45deg) translate(-9px, 6px);
transform: rotate(-45deg) translate(-9px, 6px);
}
.openMenu .hamburger .bar2 {
opacity: 0;
}
.openMenu .hamburger .bar3 {
-webkit-transform: rotate(45deg) translate(-8px, -8px);
transform: rotate(45deg) translate(-8px, -8px);
}
/*Media*/
#media(max-width: 860px) {
nav {
background: rgba(0, 0, 0, 0.8);
padding: 0 20px;
color: #fefefe;
overflow: hidden;
}
.logo {
position: fixed;
top: 0;
}
nav a {
width: 100%;
line-height: calc((100vh - 80px) / 6);
transform: translateY(80px);
visibility: hidden;
}
.openMenu a {
color: #fefefe;
visibility: visible;
}
.hamburger {
display: inline-block;
position: absolute;
right: 20px;
top: 20px;
}
.openMenu {
height: 100vh;
}
.slider {
width: 100%;
height: 23%;
}
section.sec1 {
width: 100%;
height: 30%;
}
article#video{
width: 100%;
}
video{
width: 100%;
}
aside{
border-bottom:#e8491d 3px solid;
width: 100%;
height: 250px;
}
aside#welcometext{
font-family: cursive;
width: 100%;
height: 76%;
}
aside#New{
font-family: serif;
height: 100%;
width: 100%;
}
}
/*Slideshow*/
*{
margin: 0;
padding: 0;
list-style: none;
text-decoration: none;
}
.slider {
overflow: hidden;
height: 450px%;
}
.slider figure div{
width: 20%;
float: left;
}
.slider figure img{
width: 100%;
float: left;
}
.slider figure{
position: relative;
width: 500%;
margin: 0;
left: 0;
animation: 25s slidy infinite;
}
#keyframes slidy{
0% {
left: 0%;
}
10% {
left: 0%;
}
12% {
left: -100%;
}
22% {
left: -100%;
}
24% {
left: -200%;
}
34% {
left: -200%;
}
36% {
left: -300%;
}
46% {
left: -300%;
}
48% {
left: -400%;
}
58% {
left: -400%;
}
60% {
left: -300%;
}
70% {
left: -300%;
}
72% {
left: -200%;
}
82% {
left: -200%;
}
84% {
left: -100%;
}
94% {
left: -100%;
}
96% {
left: 0%;
}
}
/*Welcome*/
article{
float: left;
margin: 0 auto;
width: 23%;
height: auto;
}
#welcometext{
float: right:
margin: 0 auto;
width: 100%;
height: auto;
border-bottom:#e8491d 3px solid;
height: 38%;
}
#News1{
margin-left: 5%;
width: 52%;
height: 7%;
display: inline-flex;
}
section.News{
border-bottom:#e8491d 3px solid;
height: 100%;
}
aside#New{
padding: 27%;
height: 100%;
width: 100%;
font-family: cursive;
}
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie-edge">
<title> Landschaft </title>
<link href='https://fonts.googleapis.com/css?family=Lato:400,300,700,900' rel='stylesheet' type='text/css'>
<link rel="stylesheet" href="style.css">
<script src="https://code.jquery.com/jquery-3.2.1.js"></script>
<link rel="stylesheet" href="https//maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
</head>
<!--Body-->
<body>
<div class="wrapper">
<nav>
<div class="hamburger" onclick="toggleMenu(this.parentNode);">
<div class="bar1"></div>
<div class="bar2"></div>
<div class="bar3"></div>
</div>
<div class="logo">Landschaft</div><a href="index.html">НАЧАЛО</a
><a href="about.html">СЪБИТИЯ</a
><a href="index.html">ПЪТЕКИ</a
><a href="index.html">ФОРУМ</a
><a href="index.html">ВРЪЗКИ</a
><a class="active" href="index.html">ВХОД</a>
</nav>
<!--Section - Slideshow-->
<section class="sec1"></section>
<section class="content">
<div class="slider">
<figure>
<div class="slide">
<img src="img/slideshow1.jpg">
</div>
<div class="slide">
<img src="img/slideshow2.jpg">
</div>
<div class="slide">
<img src="img/slideshow3.jpg">
</div>
<div class="slide">
<img src="img/slideshow4.jpg">
</div>
<div class="slide">
<img src="img/slideshow5.jpg">
</div>
</figure>
</div>
</section>
<!--Section Welcome Video-->
<section class="Welcome">
<article id="video">
<video width="295" height="238" controls autopl>
<source src="video.mp4" type="video/mp4">
</video>
</article>
<aside id="welcometext">
<h2><center>Welcome</center></h2>
<center><p>Lamium (dead-nettles) is a genus of about 40–50 species of flowering plants in the family Lamiaceae,[3] of which it is the type genus. They are all herbaceous plants native to Europe, Asia, and northern Africa, but several have become very successful weeds of crop fields and are now widely naturalised across much of the temperate world.[2][4][5]</p></center>
</aside>
</section>
<!--Section News-->
<section class="News">
<article id="News1">
<img id ="News1" src="https://cdn.pixabay.com/photo/2017/03/14/17/43/mountain-2143877_960_720.jpg">
<img id ="News1" src="https://cdn.pixabay.com/photo/2017/03/14/17/43/mountain-2143877_960_720.jpg">
<img id ="News1" src="https://cdn.pixabay.com/photo/2017/03/14/17/43/mountain-2143877_960_720.jpg">
</article>
<aside id="New">
<p> dsadas das </p>
</aside>
</section>
</div>
</body>
</html>

Adding a z-index rule to your nav element solved the problem on my end.
nav {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 80px;
padding: 0 100px;
transition: all 300ms;
z-index: 100;
}
Here is a little read on the subject

Give your header/nav a z-index:
nav {z-index:100}
Z-index positions your content in front-back space. The higher the value the closer to the front the element will be.

Create Responsive website with Side Navigation

I Making a admin panel with HTML , CSS , JQuery .
Now I Have Problem in Side Navigation .
I Need When Admin Panel Opened , Change Header And Main-Container Width .
Width : 1279 px When Opened Width:1119 px
My Code :
<%# Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="Admin_Panel_Default" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link href="../css/bootstrap.min.css" rel="stylesheet">
<link href="../css/bootstrap.css" rel="stylesheet" />
<link href="../css/bootstrap-theme.css" rel="stylesheet" />
<script src="../js/bootstrap.js"></script>
<link href="Style%20Sheet/StyleSheet.css" rel="stylesheet" />
<script src="../Scripts/jquery-3.0.0.min.js"></script>
</head>
<body>
<form id="form1" runat="server">
<div>
<header class="top-header">
<section class="navigation-icon">
<span class="top-bar"></span>
<span class="middle-bar"></span>
<span class="bottom-bar"></span>
</section>
</header>
<nav class="navigation">
<span class="title-logo">Kia<span class="kala">Kala</span ></span>
<section class="logo">
<img src="../Image/1467494806_Picasa.png" />
</section>
<ul class="navigation-ul">
<li>Space</li>
<li>Galaxy</li>
<li>Alien</li>
<li>Planet</li>
<li>Life</li>
</ul>
<section class="navigation-social">
<ul class="navigation-social-ul">
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
</section>
</nav>
<div class="right-col" role="main">
</div>
</div>
</form>
<script src="../Script/JQuery.js"></script>
<script src="../Scripts/jquery-3.0.0.min.js"></script>
</body>
</html>
CSS Code :
body {
padding: 0;
margin: 0;
background-color: #ffffff;
}
*, *:after, *:before {
box-sizing: inherit;
padding: 0;
margin: 0;
}
.top-header {
width: 1279px;
height: 57px;
background-color: #EDEDED;
float: right;
position: relative;
}
.right-col {
float: right;
background-color: #F7F7F7;
width: 1119px;
height: 1721px;
}
.navigation {
width: 70px;
height: 1721px;
background-color: #2A3F54;
float: left;
display: block;
transition: all 800ms cubic-bezier(.9,0,.33,1);
}
.logo {
width: 65px;
height: 65px;
background-color: white;
display: block;
border-radius: 50%;
margin-top: 5px;
transition: all 800ms cubic-bezier(.9,0,.33,1);
}
.logo img {
width: 65px;
height: 65px;
display: block;
float: left;
}
.title-logo {
float: right;
margin-top: 20px;
margin-right: 30px;
font-family: 'Tahoma Bold';
font-size: 35px;
color: black;
transition: all 800ms cubic-bezier(.9,0,.33,1);
visibility: hidden;
}
.title-logo .kala {
color: red;
}
.navigation-icon {
width: 70px;
margin-left: 10px;
height: 57px;
display: block;
cursor: pointer;
}
.navigation-icon .top-bar {
width: 70px;
height: 4px;
display: block;
background-color: #000000;
position: absolute;
top: 10%;
}
.navigation-icon .middle-bar {
width: 70px;
height: 4px;
display: block;
background-color: #000000;
position: absolute;
top: 30%;
}
.navigation-icon .bottom-bar {
width: 70px;
height: 4px;
display: block;
background-color: #000000;
position: absolute;
top: 50%;
}
.bottom-bar, .middle-bar, .top-bar {
margin-top: 8px;
}
.navigation-ul {
float: right;
margin-top: 200px;
visibility: hidden;
transition: all 800ms cubic-bezier(.9,0,.33,1);
}
.navigation-ul li {
list-style: none;
text-align: right;
}
.navigation-ul a {
text-decoration: none;
display: block;
font-weight: 800;
text-transform: uppercase;
color: white;
margin-bottom: 15px;
}
.navigation .navigation-social {
width: 100%;
height: 30px;
float: left;
margin-top: 30px;
transition: all 800ms cubic-bezier(.9,0,.33,1);
}
.navigation .navigation-social-ul {
float: right;
list-style: none;
visibility: hidden;
}
.navigation .navigation-social-ul li {
display: inline-block;
}
.navigation .social-icon {
width: 30px;
height: 30px;
display: inline-block;
background-color: white;
}
/*_____----------__________-------- Jquery Effect -------_________--------________*/
.navigation-open {
width: 230px;
height: 100%;
display: block;
position: absolute;
left: 0;
transition: all 800ms cubic-bezier(.9,0,.33,1);
}
.navigation-open .title-logo {
float: right;
margin-top: 20px;
margin-right: 30px;
font-family: 'Tahoma Bold';
font-size: 35px;
color: black;
transition: all 800ms cubic-bezier(.9,0,.33,1);
}
.navigation-open .title-logo .kala {
color: red;
}
JQuery Code :
$(document).ready(function () {
$(".navigation-icon").click(function () {
$(".navigation").toggleClass('navigation-open');
});
});

Simplest would be toggle a class on <body> and add corresponding css rules
$(document).ready(function () {
$(".navigation-icon").click(function () {
$(".navigation").toggleClass('navigation-open');
$('body').toggleClass('nav-open');
});
});
CSS example
body.nav-open .top-header {
width: 1119px;
}