style.css

html,
body {
    height: 100%;
}

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

@font-face {
    font-family: "Fira Code";
    font-weight: 700;
    src: url("FiraCode-Bold.ttf") format("truetype");
}

@font-face {
    font-family: "Fira Code";
    font-weight: 400;
    src: url("FiraCode-Regular.ttf") format("truetype");
}

body {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

h1 {
    font-family: "Fira Code", monospace;
    font-weight: 700;
    margin: 2rem;
}

h1 span {
    color: #f55;
    font-weight: 400;
}

.ios-switch {
    display: flex;
    flex-direction: row;
    align-items: center;
    margin: 10px 0;
}

.ios-switch .switch-body {
    background-color: #ddd;
    border: solid 1px gray;
    width: 96px;
    border-radius: 999px;
    box-shadow: inset 0 2px 4px 0 rgba(0, 0, 0, 0.1);
    transition: all 0.25s ease;
}

.ios-switch .switch-body .toggle {
    width: 48px;
    height: 48px;
    background-color: white;
    border-radius: 50%;
    box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.25);
    border: solid 1px gray;
    box-sizing: border-box;
    transition: all 0.4s ease;
}

.ios-switch.active .switch-body {
    background-color: #51d88a;
}

.ios-switch.active .switch-body .toggle {
    transform: translateX(100%);
}

.ios-switch label {
    font-size: 28px;
    font-weight: bold;
    margin-left: 20px;
    font-family: sans-serif;
}

.ios-switch input[type="checkbox"] {
    display: none;
}