.population-button {
    align-items: center;
    background: tan;
    border-radius: .25rem;
    cursor: pointer;
    margin: .25rem;
    padding: .5rem;
    overflow: hidden;
    text-align: center;
    width: 18rem;

    display: inline-flex;
    vertical-align: middle;
    transform: perspective(1px) translateZ(0);
    box-shadow: 0 0 1px rgba(0, 0, 0, 0);
    position: relative;
    transition-property: color;
    transition-duration: 0.5s;
    &.disabled {
        filter: grayscale(90%);
        opacity: .9;
        pointer-events: none;
    }
    &:hover {
        background: lighten(tan, 5%);
        .population-to-growth {
            background: lighten(lightgreen, 5%);
        }
    }
    &:active {
        animation: 700ms pop;
    }
}

@keyframes pop {
    from {
        transform: scale(0.9)
    }

    to {
        transform: scale(1.1)
    }
}

.population-button:before {
    content: '';
    position: absolute;
    z-index: -1;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: lighten(lightgreen, 5%);
    transform: scaleY(0);
    transform-origin: 50% 100%;
    transition-property: transform;
    transition-duration: 0.5s;
    transition-timing-function: ease-out;
}

.population-button:active:before {
    -webkit-transform: scaleY(1);
    transform: scaleY(1);
    -webkit-transition-timing-function: cubic-bezier(0.52, 1.64, 0.37, 0.66);
    transition-timing-function: cubic-bezier(0.52, 1.64, 0.37, 0.66);
}

.pop-growth-text {
    border-bottom: 2px solid navy;
    color: white;
    font-weight: lighter;
    margin-right: .5rem;
    padding: .25rem;
    transform: translate(-.5rem, 0);
}

.population-text {
    padding: .25rem;
}

.population-to-growth {
    background: lightgreen;
    border-radius: 2px;
    margin-left: auto;
    padding: .25rem .5rem;
}