html,
body {
    width: 100vw;
    height: 100vh;
    margin: 0;
    border: 0;
    padding: 0;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

*,
*::before,
*::after {
    -webkit-box-sizing: inherit;
    -moz-box-sizing: inherit;
    box-sizing: inherit;
}

#solution {
    width: 100%;
    height: 100%;

    background: linear-gradient(to bottom, #86725857, #2d4957f0);
    display: flex;
    justify-content: center;
    align-items: center;
}

.flip-clock-container {
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Franklin Gothic Medium', 'Arial Narrow', Arial, sans-serif;
    font-size: 170px;
    line-height: 0;
}

.flip-clock-container {
    user-select: none;
    cursor: default;
}

.flip-clock {
    display: flex;
    perspective: 1000px;
}

.digit {
    position: relative;
    width: 110px;
    height: 130px;
    box-shadow: 0 0 2px 1px rgba(0, 0, 0, 0.1);
}

.digit-left {
    margin-right: 1px;
}

.digit-right {
    margin-left: 1px;
}

.digit::before,
.digit::after {
    position: absolute;
    z-index: 0;
    display: flex;
    justify-content: center;
    width: 100%;
    height: 50%;
    overflow: hidden;
}

.digit::before {
    content: attr(data-digit-before);
    bottom: 0;
    align-items: flex-start;
}

.digit::after {
    content: attr(data-digit-after);
    top: 0;
    align-items: flex-end;
}

.card {
    position: relative;
    z-index: 1;
    width: 100%;
    height: 50%;
    transform-style: preserve-3d;
    transform-origin: bottom;
    transform: rotateX(0);
    transition: transform .7s ease-in-out;
}

.card.flipped {
    transform: rotateX(-180deg);
}

.card-face {
    position: absolute;
    display: flex;
    justify-content: center;
    width: 100%;
    height: 100%;
    overflow: hidden;
    backface-visibility: hidden;
}

.card-face-front {
    align-items: flex-end;
}

.card-face-back {
    align-items: flex-start;
    transform: rotateX(-180deg);
}

.digit::before,
.digit::before,
.card-face-front,
.card-face-back {
    background: white;
    color: black;
}

.digit,
.digit::before,
.digit::after,
.card,
.card-face {
    border-radius: 4px;
}

.digit::before,
.card-face-back {
    background: linear-gradient(0,#aaa, #ccc 50%, #fafafa);
    color: #212121;
    border-top: 1px solid black;
    border-top-left-radius: 0;
    border-top-right-radius: 0;
}

.digit::after,
.card-face-front {
    background: linear-gradient(0,#aaa, #bbb 50%, #f5f5f5);
    color: #212121;
    border-bottom: 1px solid black;
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
}

.digit-left,
.digit-left::before,
.digit-left::after,
.digit-left .card,
.digit-left .card-face {
    border-top-right-radius: 0;
    border-bottom-right-radius: 0;
}

.digit-right,
.digit-right::before,
.digit-right::after,
.digit-right .card,
.digit-right .card-face {
    border-top-left-radius: 0;
    border-bottom-left-radius: 0;
}

.colon {
    color: black;
    margin: 0 6px;
    padding-bottom: 9px;
}