html,
body {
    height: 100%;
    background: #f2f2f2;
}

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

/* Container
---------------------------------------------------------------------- */

.container {
    padding: 1rem .5rem;
    overflow: hidden;
}

/* Target Elements
---------------------------------------------------------------------- */

.mix {
    float: left;
    margin: 0 .5rem 1rem;
    background: #fff;
    border-radius: 2px;
    position: relative;
}

.mix:before {
    content: '';
    display: inline-block;
    padding-top: 56.25%;
}

/* Grid Breakpoints
---------------------------------------------------------------------- */

/* 2 Columns */

.mix {
    width: calc(50% - 1rem);
}

/* 3 Columns */

@media screen and (min-width: 541px) {
    .mix {
        width: calc(100%/3 - 1rem);
    }
}

/* 4 Columns */

@media screen and (min-width: 961px) {
    .mix,
    .gap {
        width: calc(100%/4 - 1rem);
    }
}

/* 5 Columns */

@media screen and (min-width: 1281px) {
    .mix,
    .gap {
        width: calc(100%/5 - 1rem);
    }
}