HTMLify

body {
    background-color: #121314;
    display: grid;
    place-items: center;
    height: 100vh;
}

button {
    outline: none;
    padding: 1rem 2.5rem;
    font-size: 2rem;
    position: relative;
    background: transparent;
    color: #b8ff57;
    text-transform: uppercase;
    border: 3px solid #b8ff57;
    cursor: pointer;
    transition: all 0.7s;
    overflow: hidden;
    border-radius: 40px;
}

button:hover {
    color: #222228;
}

button span {
    transition: all 0.7s;
    z-index: -1;
    content: "";
    position: absolute;
    height: 100%;
    width: 25%;
    background: #b8ff57;
}

button .first {
    right: 100%;
    top: 0;
}

button:hover .first {
    top: 0;
    right: 0;
}

button .second {
    left: 25%;
    top: -100%;
}

button:hover .second {
    top: 0;
    left: 50%;
}

button .third {
    left: 50%;
    top: 100%;
}

button:hover .third {
    top: 0;
    left: 25%;
}

button .fourth {
    left: 100%;
    top: 0;
}

button:hover .fourth {
    top: 0;
    left: 0;
}