style.css

@font-face {
    font-family: 'Open Sans';
    src: url('fonts/opensans.woff2') format('woff2'),
         url('fonts/opensans.woff') format('woff');
    font-weight: normal;
    font-style: normal;
}

html, body {
    border: 0;
    margin: 0;
    padding: 0;

    font-family: 'Open Sans', sans-serif;
    font-weight: 300;
    font-size: 14pt;
}

html {
    background-color: rgb(0, 26, 54);
    position: absolute; 
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
}

body {
    background-color: rgba(255, 255, 255, 0.12);
    color: rgb(215, 228, 252);
    padding: 1em;
    margin: auto;
    max-width: 800px;
    min-height: calc(100% - 2em);
}

a {
    color: rgb(60, 154, 241);
}

p, section > aside {
    margin-bottom: 2em;
}

h1, h2, h3 {
    font-weight: 300;
    margin: 0;
    margin-bottom: 0.75em;
}

h1 {
    font-size: 2.5em;
    margin-bottom: 0.25em;
}

h2 {
    font-size: 1.85em;
}

h3 {
    font-size: 1.5em;
}

h1::before {
    content: "# ";
    opacity: 0.5;
}
h2::before {
    content: "## ";
    opacity: 0.5;
}
h3::before {
    content: "### ";
    opacity: 0.5;
}

section {
    line-height: 1.7em;
    text-align: justify;
    margin-bottom: 3em;
}

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

aside > img {
    box-shadow: 0px 0px 5em rgba(0, 0, 0, 0.2);
    margin-bottom: 1em;
}