HTMLify

body {
    display: grid;
    place-items: center;
    height: 100vh;
    background: #151515;
    font-family: "Poppins", sans-serif;
    font-size: 27px;
    font-weight: 700;
    line-height: 1.5;
}

a {
    color: #fff;
    text-decoration: none;
    background:
        linear-gradient(to right,
            rgba(100, 200, 200, 1),
            rgba(100, 200, 200, 1)),
        linear-gradient(to right,
            rgba(255, 0, 0, 1),
            rgba(255, 0, 180, 1),
            rgba(0, 100, 200, 1));
    background-size: 100% 3px, 0 3px;
    background-position: 100% 100%, 0 100%;
    background-repeat: no-repeat;
    transition: background-size 400ms;
}

a:hover {
    background-size: 0 3px, 100% 3px;
}