style.css

@import url(https://fonts.googleapis.com/css?family=Poppins:100,100italic,200,200italic,300,300italic,regular,italic,500,500italic,600,600italic,700,700italic,800,800italic,900,900italic);
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}
body {
    display: grid;
    place-items: center;
    min-height: 100vh;
    background-color: #161616;
}

.content-container {
    width: 400px;
    height: 400px;
    padding: 0 2rem;
}
nav {
    box-shadow: 0 0 .5rem rgba(200, 0, 0, .8);
    padding: .3rem;
    border-radius: 100vw;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: relative;
}
span {
    width: 100px;
    height: 40px;
    line-height: 40px;
    text-align: center;
    cursor: pointer;
    color: #fff;
}
.slider {
    position: absolute;
    /* width: 100px;
    height: 40px;
    left: 0; */
    background-color: rgba(255, 255, 255, .1);
    border-radius: 100vw;
    pointer-events: none;
    transition: 200ms ease-in-out left;
}

.content {
    box-shadow: 0 0 .5rem rgba(200, 0, 0, .8);
    margin-top: 2rem;
    border-radius: 1rem;
    padding: 0;
}
p {
    color: #fff;
    display: none;
}
strong {
    font-size: 1.2rem;
    border-bottom: 1px solid rgba(255, 255, 255, .3);
    display: inline-block;
    margin-bottom: 0.5rem;
    padding-bottom: 0.5rem;
}

.show {
    display: block;
}