seat.css

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

html {
    font-size: 16px;
}

.plane {
    margin: 20px auto;
    max-width: 300px;
}

.cockpit {
    height: 250px;
    position: relative;
    overflow: hidden;
    text-align: center;
    border-bottom: 5px solid #d8d8d8;
    &:before {
        content: "";
        display: block;
        position: absolute;
        top: 0;
        left: 0;
        height: 500px;
        width: 100%;
        border-radius: 50%;
        border-right: 5px solid #d8d8d8;
        border-left: 5px solid #d8d8d8;
    }
    h1 {
        width: 60%;
        margin: 100px auto 35px auto;
    }
}

.exit {
    position: relative;
    height: 50px;
    &:before,
    &:after {
        content: "EXIT";
        font-size: 14px;
        line-height: 18px;
        padding: 0px 2px;
        font-family: "Arial Narrow", Arial, sans-serif;
        display: block;
        position: absolute;
        background: green;
        color: white;
        top: 50%;
        transform: translate(0, -50%);
    }
    &:before {
        left: 0;
    }
    &:after {
        right: 0;
    }
}

.fuselage {
    border-right: 5px solid #d8d8d8;
    border-left: 5px solid #d8d8d8;
}

ol {
    list-style: none;
    padding: 0;
    margin: 0;
}

.row {}

.seats {
    display: flex;
    flex-direction: row;
    flex-wrap: nowrap;
    justify-content: flex-start;
}

.seat {
    display: flex;
    flex: 0 0 14.28571428571429%;
    padding: 5px;
    position: relative;
    &:nth-child(3) {
        margin-right: 14.28571428571429%;
    }
    input[type=checkbox] {
        position: absolute;
        opacity: 0;
    }
    input[type=checkbox]:checked {
        +label {
            background: #bada55;
            -webkit-animation-name: rubberBand;
            animation-name: rubberBand;
            animation-duration: 300ms;
            animation-fill-mode: both;
        }
    }
    input[type=checkbox]:disabled {
        +label {
            background: #dddddd;
            text-indent: -9999px;
            overflow: hidden;
            &:after {
                content: "X";
                text-indent: 0;
                position: absolute;
                top: 4px;
                left: 50%;
                transform: translate(-50%, 0%);
            }
            &:hover {
                box-shadow: none;
                cursor: not-allowed;
            }
        }
    }
    label {
        display: block;
        position: relative;
        width: 100%;
        text-align: center;
        font-size: 14px;
        font-weight: bold;
        line-height: 1.5rem;
        padding: 4px 0;
        background: #F42536;
        border-radius: 5px;
        animation-duration: 300ms;
        animation-fill-mode: both;
        &:before {
            content: "";
            position: absolute;
            width: 75%;
            height: 75%;
            top: 1px;
            left: 50%;
            transform: translate(-50%, 0%);
            background: rgba(255, 255, 255, .4);
            border-radius: 3px;
        }
        &:hover {
            cursor: pointer;
            box-shadow: 0 0 0px 2px #5C6AFF;
        }
    }
}

@-webkit-keyframes rubberBand {
    0% {
        -webkit-transform: scale3d(1, 1, 1);
        transform: scale3d(1, 1, 1);
    }
    30% {
        -webkit-transform: scale3d(1.25, 0.75, 1);
        transform: scale3d(1.25, 0.75, 1);
    }
    40% {
        -webkit-transform: scale3d(0.75, 1.25, 1);
        transform: scale3d(0.75, 1.25, 1);
    }
    50% {
        -webkit-transform: scale3d(1.15, 0.85, 1);
        transform: scale3d(1.15, 0.85, 1);
    }
    65% {
        -webkit-transform: scale3d(.95, 1.05, 1);
        transform: scale3d(.95, 1.05, 1);
    }
    75% {
        -webkit-transform: scale3d(1.05, .95, 1);
        transform: scale3d(1.05, .95, 1);
    }
    100% {
        -webkit-transform: scale3d(1, 1, 1);
        transform: scale3d(1, 1, 1);
    }
}

@keyframes rubberBand {
    0% {
        -webkit-transform: scale3d(1, 1, 1);
        transform: scale3d(1, 1, 1);
    }
    30% {
        -webkit-transform: scale3d(1.25, 0.75, 1);
        transform: scale3d(1.25, 0.75, 1);
    }
    40% {
        -webkit-transform: scale3d(0.75, 1.25, 1);
        transform: scale3d(0.75, 1.25, 1);
    }
    50% {
        -webkit-transform: scale3d(1.15, 0.85, 1);
        transform: scale3d(1.15, 0.85, 1);
    }
    65% {
        -webkit-transform: scale3d(.95, 1.05, 1);
        transform: scale3d(.95, 1.05, 1);
    }
    75% {
        -webkit-transform: scale3d(1.05, .95, 1);
        transform: scale3d(1.05, .95, 1);
    }
    100% {
        -webkit-transform: scale3d(1, 1, 1);
        transform: scale3d(1, 1, 1);
    }
}

.rubberBand {
    -webkit-animation-name: rubberBand;
    animation-name: rubberBand;
}