:root {
    --block-shadow: 0 0 0 2px #000;
}
* {
    box-sizing: border-box;
}
html {
    font-size: 100%;
}
body {
    font-size: 1rem;
    font-family: Arial, Helvetica, sans-serif;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0;
}
#board {
    margin: 2rem 1rem;
    position: relative;
}
.nav {
    display: table;
    margin: 0 auto;
}
#rand, #reset, #restart {
    margin: 2rem 1rem;
    text-align: center;
    display: inline-block;
    padding: .7em 2rem;
    border-radius: 8px;
    font-size: 1.2rem;
    cursor: pointer;
}
#rand {
    background: #27a11b;
    border-bottom: 4px solid #1a7b11;
    color: #fff;
}
#rand:hover {
    background: #1d8b13;
}
#reset {
    background: #979797;
    border-bottom: 4px solid #656565;
    color: #fff;
}
#reset:hover {
    background: #7f7f7f;
}
#restart {
    background: #363636;
    border-bottom: 4px solid #1d1d1d;
    color: #fff;
}
#restart:hover {
    background: #242424;
}
#result {
    display: table;
    margin: 0 auto 2rem;
    font-size: 2rem;
    height: 3rem;
}
.table {
    display: flex;
}
.block {
    width: 80px;
    margin: 0 10px;
    border-radius: 0 0 40px 40px;
    overflow: hidden;
    transition: transform ease 200ms, box-shadow ease 200ms;
    border-top: 1rem solid #f1f1f1;
    box-shadow: var(--block-shadow);
}
.block:hover {
    box-shadow: var(--block-shadow),0 1rem 1rem rgba(0, 0, 0, 0.18);
    cursor: pointer;
}
.block.set {
    box-shadow:var(--block-shadow),0 1rem 1rem rgba(0, 0, 0, 0.38);
    position: relative;
    transform: translateY(-1rem);
}
.item {
    width: 100%;
    height: 80px;
    position: relative;
}
.item::after {
    content: '';
    color: #fff;
    position: absolute;
    font-size: 1.5rem;
    top: calc(50% - .5em);
    left: 0;
    right: 0;
    text-align: center;
}
[data-item=""] {
    background: #f1f1f1;
}
[data-item=""]::after {
    content: '-';
    color: #494949;
}
[data-item="a"] {background: #ecc639;}
[data-item="a"]::after {content: 'A'}

[data-item="b"] {background: #8304a7;}
[data-item="b"]::after {content: 'B'}

[data-item="c"] {background: #28a106;}
[data-item="c"]::after {content: 'C'}

[data-item="d"] {background: #236dee;}
[data-item="d"]::after {content: 'D'}

[data-item="e"] {background: #e50a36;}
[data-item="e"]::after {content: 'E'}

[data-item="f"] {background: #009a7c;}
[data-item="f"]::after {content: 'F'}

[data-item="g"] {background: #000000;}
[data-item="g"]::after {content: 'G'}

[data-item="h"] {background: #c77272;}
[data-item="h"]::after {content: 'H'}

[data-item="i"] {background: #ef530b;}
[data-item="i"]::after {content: 'I'}

[data-item="j"] {background: #7e9072;}
[data-item="j"]::after {content: 'j'}

[data-item="k"] {background: #660038;}
[data-item="k"]::after {content: 'K'}

[data-item="l"] {background: #b4b4b4;}
[data-item="l"]::after {content: 'L'}