.btn-style507::before {
    width: 15%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    right: unset;
    background-color: #fff;
    transform: rotateZ(45deg) translate(-50%, 50%);
    transition: all 0.4s;
    content: "";
    z-index: -1;
}


@keyframes ani507 {
    10% {
        width: 0;
        transform: rotateZ(-45deg) translate(-100%, -50%);
    }

    20% {
        width: 0;
        transform: rotateZ(0) translate(-100%, 85%);
    }

    60% {
        width: 100%;
        transform: rotateZ(0) translate(0, 85%);
    }

    100% {
        width: 100%;
        transform: rotateZ(0) translate(0, 0);
    }
}