body {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    height: 400px;
    width: 100%;
    font-family: monospace;
}

a, a:visited, a:hover {
    color:darkorchid
    text-decoration: none;
}

h1 {
    color: aqua;
    letter-spacing: 1px;
}

.container {
    margin: 30px;
    width: 70px;
    height: 30px;
    position: relative;
    overflow: hidden;
}

.container input[type="checkbox"]{
    visibility: hidden;
}

.container label{
    width: 70px;
    height: 30px;
    border-radius: 50px;
    position: absolute;
    top: 0;
    left: 0;
    background-color: aquamarine;
    transition: background 0.2s ease-in-out;
}

.container label:after{
    content: "\2639";
    width: 30px;
    height: 30px;
    font-size: 25px;
    position: absolute;
    top: 0;
    left: -1px;
    transition: all .2s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.container input[type="checkbox"]:checked + label:after{
    left: 45px;
    content:"\1F60A";
}

.container input[type="checkbox"]:checked + label{
    background-color: darkorange;
}