html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed,
figure, figcaption, footer, header, hgroup,
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure,
footer, header, hgroup, menu, nav, section {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
    content: '';
    content: none;
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}

body {
    background: #eee;
}

.mixitup-control,
.mixitup-pager {
    cursor: pointer;
    display: inline-block;
    padding: .5rem;
    background: #eee;
}

.mixitup-control-active,
.mixitup-pager-active {
    font-weight: bold;
}

.mixitup-pager-disabled {
    opacity: .8;
}

.mix {
    vertical-align: top;
    background: skyblue;
    border-radius: 5px;
    margin: 2rem;
    color: transparent;

    transition: opacity 300ms;

    -webkit-user-select: none;
}

.mix,
.gap {
    display: inline-block;
    width: 6%;
    margin: 0 2rem;
}

.mix {
    margin: 2rem;
}

.mix:before {
    content: '';
    display: inline-block;
    padding-top: 100%;
}

.mixitup-target-placeholder {
    background: transparent !important;
    border: 2px dashed #ccc;
    box-sizing: border-box;
}

.mixitup-target-dragging {
    opacity: .5;
}

.mixitup-target-closest {
    border: 3px solid orange;
}

.sandbox {
    overflow: hidden;
    text-align: justify;
    background: #333;
    min-height: 2rem;
}

.sandbox:after {
    content: '';
    width: 100%;
    display: inline-block;
}

.sandbox__mixitup .mix {

}

.mix.cat-2 {
    background: violet;
}

.mix.cat-3 {
    background: yellow;
}

.mix.cat-4 {
    background: aquamarine;
}