style.css

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

html {
    font-size: 10px;
}

body {
    width: 100%;
    background: #eeeeee;
    font-family: 'helvetica neue', sans-serif;
    font-size: 2rem;
    font-weight: 1.5;
}

header {
    text-align: center;
    width: 100%;
    padding: 0 1rem;
    height: 50vh;
    background: repeating-linear-gradient(
        45deg,
        teal,
        seagreen 50px,
        yellowgreen 30px
    );

    display: flex;
    align-items: center;
    justify-content: center;
}

h1 {
    color: white;
    font-size: 7vw;
    text-shadow: 3px 4px 0 rgba(0, 0, 0, 0.2);
}

nav {
    background: black;
    width: 100%;
    transition: all 0.5s;
    position: relative;
    z-index: 1;
}
body.fixed-nav nav {
    position: fixed;
    box-shadow: 0 5px 0 rgba(0, 0, 0, 0.1);

    top: 0;
    left: 0;
    right: 0;
}

nav ul {
    width: 100%;
    min-height: 5rem;
    list-style: none;

    display: flex;
    flex-flow: row wrap;
    justify-content: center;
    align-items: center;
}

nav ul li {
    flex: 1;
    text-align: center;
    height: 5rem;

    display: grid;
    place-items: center;
}
nav ul li a {
    text-decoration: none;
    display: inline-block;
    padding: 1rem;
    color: white;
    transition: all 0.5s;
    text-transform: uppercase;
    border-radius: 0.5rem;
}
nav ul li a:hover {
    background: linear-gradient(45deg, seagreen, yellowgreen);
}

li.logo {
    max-width: 0;
    overflow: hidden;
    background: white;
    transition: all 0.5s;
    font-weight: 600;
    font-size: 3rem;
    border-radius: 0 0 2.5rem 0;
}

.fixed-nav li.logo {
    max-width: 500px;
    overflow: visible;
}

li.logo a {
    color: black;
}

.site-wrap {
    max-width: 70rem;
    width: 90%;
    margin: 7rem auto;
    background: white;
    padding: 3rem;
    text-align: justify;
    box-shadow: 0 0 10px 5px rgba(0, 0, 0, 0.05);
    transform: scale(0.98);
    transition: transform 0.5s;
}
body.fixed-nav .site-wrap {
    transform: scale(1);
}

.site-wrap p {
    margin: 1.5rem 0;
}