<section class="center">
    <div class="center__inner">
        <div class="content">
            <label class="button" for="modal__state"><i class="fa fa-rocket"></i> Launch it!</label>
            <input type="checkbox" name="modal__state" id="modal__state" class="modal__state">
            <div class="modal__overlay">
                <label for="modal__state" class="modal__overlay-close"></label>
                <div class="modal">
                    <label class="button button--close modal__close" for="modal__state"><i class="fa fa-times"></i></label>
                    <h1>Here is the modal!</h2>
                    <p class="lede">Created with pure CSS, and probably non-functional in many browsers.</p> 
                    <p>The <span class="button button--inline">launch</span> button is a <span class="code">&lt;label&gt;</span> attached to a radio <span class="code">&lt;input&gt;</span>. Clicking the label toggles the radio input. Using the <span class="code">:checked</span> pseudo-selector and the <span class="code">+</span> sibling selector, the <span class="code">.modal__wrapper</span> is made visible when the radio is checked.</p>
                    
                    <p>The close button in a second label/radio input with the same name attribute, so when it is clicked, the launch button loses its :checked state and the modal goes back to <span class="code">display: none</span>.<p>
                </div>
            </div>
        </div>
    </div>
</section>
$white: #fff;
$light: #B8AE9C;
$dark: #595241;
$blue: #ACCFCC;
$red: #8A0917;
$bHeight: 4px;

html, body {
    height: 100%;
}
body {
    background-color: $light;
    color: $dark;
    font-weight: 200;
}
p {
    line-height: 1.5;
}
h1 {
    margin: 0;
    font-weight: inherit;
}
.lede {
    font-size: 1.25em;
}
.code {
    padding: 2px;
    font-size: .9em;
    border-radius: 4px;
    font-family: 'Source Code Pro', Menlo, Consolas, Monaco, monospace;
    background: hsla(100,0%,100%,.5);
}

/* horizontal & vertical centering */
.center {
    display: table;
    width: 100%;
    height: 100%;
}
    .center__inner {
        display: table-cell;
        text-align: center;
        vertical-align: middle;
    }

/* modal */
@keyframes fade-in {
    0% {opacity: 0;}
    100% {opacity: 1;}
}
.modal__overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,.4);
    display: none;
}
/* display the modal overlay when the input[type=radio] is checked */
.modal__state:checked + .modal__overlay {
    opacity: 1;
    animation: fade-in .4s;
    display: block;
}
@keyframes scoot-up {
  0%   { margin-top: 80px;}
  100%  { margin-top: 50px; }
}
.modal {
    position: relative;
    margin: 50px;
    margin-top: 80px;
    padding: 40px 20px;
    background: lighten($light,10%);
    text-align: left;
    box-shadow: 0px 0px 38px rgba(0,0,0,.2);
}
.modal__state:checked + .modal__overlay .modal {
    margin-top: 50px;
    animation: scoot-up .2s;
    animation-timing-function: ease-out;
    transform-origin: 50% 0px;
}
.modal__close {
    position: absolute;
    top: 40px;
    right: 20px;
}
.modal__overlay-close {
    height: 100%;
    width: 100%;
    position: absolute;
    left: 0;
    top: 0;
}

/* the input[type=radio] that's toggled when the label is clicked */
.modal__state {
    display: none;
}


/* button styles */
.button {
    display: inline-block;
    padding: 1em;
    font-weight: bold;
    border-radius: 4px;
    box-shadow: 0 $bHeight 0 darken($blue,10%);
    background: $blue;
    color: $dark;
}
.button:hover, .button:focus {
    cursor: pointer;
    background-color: lighten($blue, 10%);
    box-shadow: 0 $bHeight 0 $blue;
}
.button:active {
    margin-top: $bHeight;
    margin-bottom: -$bHeight;
    box-shadow: 0 0 0 $blue;
}

/* close button */
.button--close {
    padding: .2em .5em;
    background-color: $red;
    box-shadow: 0 $bHeight 0 darken($red,10%);
    color: $white;
}
.button--inline {
    padding: .25em .5em;
}
.button--close:hover,
.button--close:focus {
    background-color: lighten($red, 10%);
    box-shadow: 0 $bHeight 0 $red;
}
.button--close:active {
    box-shadow: 0 0 0 $red;
}
View Compiled

External CSS

  1. https://maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.