Cutaway Indicator

html,
body {
    height: 100%;
    position: relative;
}
body {
    background-color: rebeccapurple;
    background-image: linear-gradient(transparent 0%, coral 100%);
    font: 400 normal 24px/2em sans-serif;
}
button {
    background-color: gray;
    color: white;
    display: block;
    overflow: visible;
    padding: 1em 2em 1em 1em;
    border: 0;
    position: absolute;
    top: 50%;
    left: 50%;
    text-decoration: none;
    font-weight: 600;
    transform: translate3d(-50%, -50%, 0);
    &:before,
    &:after {
        content: "";
        width: 0;
        height: 0;
        border-right: 2.5em solid gray;
        position: absolute;
        right: 100%;
        transition: all .5s;
    }
    &:before {
        border-bottom: 3em solid transparent;
        top: 0;
    }
    &:hover:before,
    &:focus:before {
        border-right-color: rgba(green, .6);
    }
    &:after {
        border-top: 3em solid transparent;
        bottom: 0;
    }
    &:hover:after,
    &:focus:after {
        border-right-color: rgba(orange, .6);
    }
}