style.css

/* Google Font Poppins */
@import url(https://fonts.googleapis.com/css2?family=Crimson+Pro:wght@200..900&display=swap);
* {
    padding: 0%;
    margin: 0%;
    box-sizing: border-box;
}

body {
    width: 100%;
    height: 100vh;
    background-color: #131312;
    font-family: 'Poppins' , sans-serif;
    display: flex;
    align-items: center;
    justify-content: center;
}

header {
    width: 85%;
    height: 95%;
    border: 1px solid #fff;
    display: flex;
    flex-wrap: wrap;
    overflow: hidden;
}

header .menu-side, .song-side {
    position: relative;
    width: 25%;
    height: 95%;
    border: 1px solid #ffffff;
    background-color: #111727;
    box-shadow: 5px 0px 2px #090f1f;
    color: #fff;
}

header .song-side {
    width: 75%;
    background: #0b1320;
}

header .master-play {
    width: 100%;
    height: 10%;
    background: #111727;
    box-shadow: 0px 3px 8px #090f1f;
}

header .menu-side h1 {
    font-size: 20px;
    margin: 15px 0px 0px 20px;
    font-weight: 500;
}

header .menu-side .playlist {
    margin: 40px 0px 0px 20px;
}

header .menu-side .playlist h4 {
    font-size: 14px;
    font-weight: 400;
    padding-bottom: 10px;
    color: #4c5262;
    cursor: pointer;
    transition: .3s linear;
}

header .menu-side .playlist h4:hover {
    color: #fff;
}

header .menu-side .playlist h4:hover span {
    position: relative;
}