styles.css

* {
    box-sizing: border-box;
}

body {
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    background-color: #333;
    margin: 0;
    overflow-x: hidden;
    color: #222;
}

.container {
    width: 100vw;
    background-color: #fafafa;
    padding: 1vw 5vw;
    min-height: 100vh;
    height: 50vh;
    transform-origin: top left;
    transition: transform 0.5s linear;
}

.container.show-nav {
    transform: rotate(-20deg);
}

.circle-container {
    position: fixed;
    top: -10vw;
    left: -10vw;
}

.container.show-nav .circle {
    transform: rotate(-70deg);
}

.circle {
    background-color: cadetblue;
    height: 20vw;
    width: 20vw;
    border-radius: 50%;
    position: relative;
    transition: transform 0.5s linear;
}

.circle button {
    height: 10vw;
    background: transparent;
    border: 0;
    font-size: 3vw;
    color: #fff;
    cursor: pointer;
    position: absolute;
    top: 50%;
    left: 50%;
}

.circle button:focus {
    outline: 0;
}

.circle button.open {
    left: 60%;
}

.circle button.close {
    top: 60%;
    transform: rotate(90deg);
    transform-origin: top left;
}

.content {
    max-width: 100vw;
    margin: 10vw auto;
}

.content p{
    line-height: 2.5vw;
}

.container.show-nav + nav li {
    transform: translateX(0);
    transition-delay: 0.3s;
}

nav {
    position: fixed;
    bottom: 3vw;
    left: 0;
    z-index: 100;
}

nav ul {
    list-style-type: none;
    padding-left: 2vw;
}

nav ul li {
    text-transform: uppercase;
    color: #fff;
    margin: 2vw 0;
    cursor: pointer;
    transform: translateX(-100%);
    transition: transform 0.4s ease-in;
}

nav ul li i {
    font-size: 20px;
    margin-right: 1vw;
}

nav ul li:nth-child(2) {
    margin-left: 2vw;
    transform: translateX(-140%);
}

nav ul li:nth-child(3) {
    margin-left: 3vw;
    transform: translateX(-170%);
}