CSS responsive triangles

Pure CSS responsive triangles set to 50% base as described on http://codeitdown.com/pure-css-responsive-triangles

by josedvq

HTML

<div class="triangle-up-right"></div>

<div class="triangle-down-right"></div>

<div class="triangle-down-left"></div>

<div class="triangle-up-left"></div>

CSS

.triangle-up-right {
    width: 0;
    height: 0;
    padding-left:25%;
    padding-top: 25%;
    overflow: hidden;
}
.triangle-up-right:after {
    content: "";
    display: block;
    width: 0;
    height: 0;
    margin-left:-500px;
    margin-top:-500px;
    
    border-left: 500px solid transparent;
    border-top: 500px solid #4679BD;
}

.triangle-down-right {
    width: 25%;
    height: 0;
    padding-top:25%;
    overflow: hidden;
}
.triangle-down-right:after {
    content: "";
    display: block;
    width: 0;
    height: 0;
    margin-top:-500px;
    
    border-top: 500px solid transparent;
    border-right: 500px solid #4679BD;
}
.triangle-down-left {
    width: 25%;
    height: 0;
    padding-bottom: 25%;
    overflow: hidden;
}
.triangle-down-left:after {
    content: "";
    display: block;
    width: 0;
    height: 0;
    border-right: 500px solid transparent;
    border-bottom: 500px solid #4679BD;
}

.triangle-up-left {
    width: 0;
    height: 0;
    padding-bottom: 25%;
    padding-left: 25%;
    overflow: hidden;
}
.triangle-up-left:after {
    content: "";
    display: block;
    width: 0;
    height: 0;
    margin-left: -500px;
    border-bottom: 500px solid transparent;
    border-left: 500px solid #4679BD;
}