* {
    box-sizing: border-box;
}

body {
    font-family: "Open Sans",
        sans-serif;
    font-size: 20px;
    color: #444;
    text-align: center;
    line-height: 1.5;
}

nav,
footer {
    padding: 1% 0;
    background-color: #aaa;
}

nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 10;
}

header {
    padding: 45px 15px;
}

section {
    min-height: 200px;
    padding: 30px 15px;
    background-color: #bbb;
}

section:nth-child(even) {
    background-color: #ddd;
}

p {
    margin: 0 auto;
    max-width: 650px;
}

p+p {
    margin-top: 15px;
}