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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Adding Classes

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html> tag. If you want to add classes there that can affect the whole document, this is the place to do it.

About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

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Insecure Resource

The resource you are linking to is using the 'http' protocol, which may not work when the browser is using https.

CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.

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Packages

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Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

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Using packages here is powered by esm.sh, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ESM usage.

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HTML 

              
                
    <nav id="menu" role="navigation">
        <div class="brand">&Aopf;</div>            
        <ul>
            <li><a href="#">Item 1</a></li>
            <li><a href="#">Item 2</a></li>
            <li><a href="#">Item 3</a></li>
        </ul>
    </nav>
    <div class="page-wrap">
        <button id="menu-toggle"></button>
        <div class="container" role="main">
            <article>
                <h2>Vanilla Javascript push menu</h2>
                    <p>Sometimes you just need a really simple push menu, without any Javascript Libraries. I made this in a rush for a client with the instructions to not use any jQuery.</p>
                    <p>I like the thought of adding a class to the body and climb the DOM instead of adding classes to the affected elements.</p>
                    <p>Less is more.</p>
            </article>
      </div>
   </div>
!

CSS 

              
                body {
    width: 100%;
    height: 100%;
    margin: 0;

    font-family: "Roboto", sans-serif;

    color: #fff;
    background-color: #232629;
}

p {
    line-height: 1.7;
}
h2 {
    margin-top: 30px;

    font-size: 1.7em;
    line-height: 1;

    letter-spacing: 2px;
    text-transform: uppercase;
}
/* PUSH MENU */
#menu {
    position: fixed;
    top: 0;
    left: -300px;

    width: 300px;
    height: 100%;
    padding: 50px 30px;
    -webkit-box-sizing: border-box;
       -moz-box-sizing: border-box;
            box-sizing: border-box;

    -webkit-transition: all .3s ease-in;
       -moz-transition: all .3s ease-in;
         -o-transition: all .3s ease-in;
            transition: all .3s ease-in;
    text-align: center;

    background-color: #fff;
}
#menu .brand {
    height: 51px;

    font-size: 70px;
    font-weight: 900;
    line-height: .6;

    color: #ddd;
}
#menu ul {
    padding: 0;
    margin-top: 30px;
}

#menu ul li a {
    display: block;

    font-weight: 900;
    line-height: 50px;

    -webkit-transition: all .3s ease;
       -moz-transition: all .3s ease;
         -o-transition: all .3s ease;
            transition: all .3s ease;
    text-decoration: none;
    text-transform: uppercase;

    color: #232629;
    border-top: 1px solid #eee;
}
#menu ul li:last-child a {
    border-bottom: 1px solid #eee;
}
#menu ul li a:hover {
    letter-spacing: 1px;
}
body.open #menu {
    left: 0;
}
/* MAIN PAGE */
.page-wrap {
   
    padding: 50px;
    -webkit-box-sizing: border-box;
       -moz-box-sizing: border-box;
            box-sizing: border-box;

    -webkit-transition: all .3s ease-in;
       -moz-transition: all .3s ease-in;
         -o-transition: all .3s ease-in;
            transition: all .3s ease-in;
}
body.open .page-wrap {
    margin-left: 300px;
}

/* MENU TOGGLE ICON */

button:focus {
    outline: none;
}
#menu-toggle {
    position: relative;

    width: 51px;
    height: 51px;

    cursor: pointer;

    border: none;
    -webkit-border-radius: 50px;
       -moz-border-radius: 50px;
            border-radius: 50px;
    background: #fff;
}
#menu-toggle:before,
#menu-toggle:after {
    position: absolute;

    content: "";
    content: "";
    -webkit-transition: all .5s ease;
       -moz-transition: all .5s ease;
         -o-transition: all .5s ease;
            transition: all .5s ease;

    background-color: #232629;
}

#menu-toggle:before {
    top: 12px;
    left: 25px;

    width: 1px;
    height: 27px;
}
#menu-toggle:after {
    top: 25px;
    left: 12px;

    width: 27px;
    height: 1px;
}

body.open button#menu-toggle:before,
body.open button#menu-toggle:after {
    -webkit-transform: rotate(45deg);
        -ms-transform: rotate(45deg);
            transform: rotate(45deg);
}
/* CONTENT CONTAINER */
.container {
    max-width: 600px;
    min-width: 200px;
    margin: 0 auto;
}
!

JS 

              
                
//Exelent little functions to use any time when class modification is needed
function hasClass(ele, cls) {
    return !!ele.className.match(new RegExp('(\\s|^)' + cls + '(\\s|$)'));
}

function addClass(ele, cls) {
    if (!hasClass(ele, cls)) ele.className += " " + cls;
}

function removeClass(ele, cls) {
    if (hasClass(ele, cls)) {
        var reg = new RegExp('(\\s|^)' + cls + '(\\s|$)');
        ele.className = ele.className.replace(reg, ' ');
    }
}

//Add event from js the keep the marup clean
function init() {
    document.getElementById("menu-toggle").addEventListener("click", toggleMenu);
}

//The actual fuction
function toggleMenu() {
    var ele = document.getElementsByTagName('body')[0];
    if (!hasClass(ele, "open")) {
        addClass(ele, "open");
    } else {
        removeClass(ele, "open");
    }
}

//Prevent the function to run before the document is loaded
document.addEventListener('readystatechange', function() {
    if (document.readyState === "complete") {
        init();
    }
});
!
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