<a href="#" class="btn">Transition</a>

<div class="overlay">
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
    <div class="bar"></div>
</div>
$teal: #8ba3b9;

*,
*:before,
*:after {
    box-sizing: border-box;
}

html {
    overflow: hidden;
}

.btn {
    position: absolute;
    bottom: 0;
    left: 50%;
    padding: 1rem;
    font-size: 2rem;
    color: $teal;
    text-decoration: none;
    background: white;
    border: solid mix(white, $teal, 25%);
    border-width: 1px 1px 0;
    transform: translateX(-50%);
    z-index: 99;
}

.overlay {
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    
    &.show {
        .bar {
            transform: scale(1, 1)
                       translate3d(0,0,0);
            transform-origin: 0 0;
        }
    }

    .bar {
        position: absolute;
        width: 10.1vw;
        background: $teal;
        top: 0;
        bottom: 0;
        transform: scale(0, 1)
                   translate3d(0,0,0);
        transform-origin: 100% 100%;
        transition: transform 0.5s ease-in-out;
        border-left: 1px solid mix(white, $teal, 25%);
        
        &:first-of-type {
            border-left: none;
        }
        
        $light: $teal;
        $dark: mix(black, $teal, 5%);        
        @for $x from 1 through 10 {
            &:nth-of-type(#{$x}) {
                left: ($x - 1) * 10vw;
                background: linear-gradient(to right, $light 0%, $dark 100%);
                transition-delay: 0.05s * $x;
            }
            
            $light: $dark;
            $dark: mix(black, $teal, ($x * 5%));
        }
    }
}
View Compiled
$('.btn').click(function(e) {
    e.preventDefault();    
    $('.overlay').toggleClass('show');
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js