Depois de colocar a propriedade float na tag "main" e definir as porcentagens o meu aside continuou em baixo da página. HTML aside
<aside class="navegacao-site">
<nav>
<h1>João da Silva</h1>
<ul>
<li><a href="home.html">Home</a></li>
<li><a href="portfolio.html">Potfolio</a></li>
<li><a href="sobremim.html">Sobre mim</a></li>
<li><a href="blog.html">Blog</a></li>
<li><a href="contato.html">Contato</a></li>
</ul>
<ul class="icones-sociais">
<li>
<a href="hhtp://github/joaodasilva" class="github">Github</a></li>
<li>
<a href="hhtp://twitter/joaodasilva" class="twitter">Twitter</a></li>
<li>
<a href="hhrp://linkedin/joaodasilva" class="linkedin">LinkedIn</a></li>
</ul>
</nav>
</aside>
CSS
.titulo-principal {
background-color: rgb(120, 30, 60);
color: #fff;
text-align: center;
padding: 25px;
margin: 0px;
border-bottom: 10px solid #000;
font-size: 50px;
text-transform: uppercase;
}
h2 {
font-size: 30px;
clear: both;
}
body {
font-size: 120%;
background-color: #F2FFFC;
}
p {
text-align: justify;
font-family: "crimson text", serif;
line-height: 30px;
margin: 20px;
}
h1, h2 {
font-family: "open sans condensed", sans-serif;
}
blockquote {
background-color: #D9E5E3;
border: 10px solid #C2CCCA;
border-bottom-color: #333;
border-right-color: #fff;
width: 250px;
height: auto;
box-sizing: border-box;
margin: 20px 40px;
}
.citacao-jose {
float: right;
}
.citacao-manoel {
float: left;
}
nav {
color: #F2FFFC;
text-align: center;
line-height: 25px;
}
nav a {
text-transform: lowercase;
}
footer {
background-color: #000;
color: #F2FFFC;
margin: 0px;
clear: both;
}
footer li {
display: inline-block;
}
.navegacao-site {
background-color: #3C1D3D;
color: #F2FFFC;
text-align: center;
}
.navegacao-site a {
color: #fff;
font-family: "open sans condensed", sans-serif;
text-decoration: none;
line-height: 30px;
}
.navegacao-site h1 {
font-size: 30px;
margin-bottom: 25px;
text-transform: uppercase;
}
main a {
color: #851944;
text-decoration: none;
}
main {
float: left;
width: 85%;
}
blockquote, footer, aside {
padding: 20px;
}
aside, img {
float: right;
box-sizing: border-box;
}
aside {
clear: right;
width: 15%;
}
.texto-principal {
width: 720px;
margin-left: auto;
margin-right: auto;
padding: 30px 0px;
}
strong {
font-weight: bold;
}
em {
font-style: italic;
}
.tags {
color: #851944;
background-color: #F2FFFC;
}
article {
padding-bottom: 30px;
border-bottom: 1px solid #ccc;
margin-bottom: 20px;
}
.leia-mais {
padding: 8px;
margin: 16px;
display: block;
font-size: 24px;
text-align: center;
background-color: #E6E7E8;
}
.data {
margin-top: 15px;
}
.icones-sociais a{
display: inline-block;
width: 40px;
height: 40px;
font-size: 0px;
}
.github {
background-image: url(github.png);
}
.twitter {
background-image: url(twitter.png);
}
.linkedin {
background-image: url(linkedin.png);
}
.icones-sociais li {
display: inline-block;
}