html {
  font-size: 16px;
  box-sizing: border-box;
}
*,
*:before,
*:after {
  box-sizing: border-box;
}
body {
  margin: 0;
  font: 1rem sans-serif;
}
h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0 0 0.2em 0;
}
ul {
  padding: 0;
  margin: 0;
  list-style: none;
}
.logo {
  position: relative;
  padding: 1.2em 0;
  background: url(../imagens/logo.png) center no-repeat;
}
.logo span {
  position: absolute;
  top: -20000px;
}
.topo h1 {
  width: 200px;
  height: 50px;
  margin: 0 auto;
}
.topo ul {
  background: #c8e0e8;
  border-bottom: 1px solid #cacaca;
}
.topo li {
  display: inline-block;
  border-right: 1px solid #999;
}
.topo li a {
  text-transform: uppercase;
  font-weight: bold;
  color: #000;
  text-decoration: none;
  display: block;
  padding: 8px 20px;
}
.topo li a:hover {
  color: #666;
}
.topo li:first-child a {
  border-left: 1px solid #999;
}
.principal a {
  color: #027399;
  text-decoration: none;
}
.thumb img {
  display: block;
  width: 80px;
}
.topo,
.rodape {
  text-align: center;
  background: #eaefef;
  padding: 1px 0;
}
.topo {
  margin-bottom: 4px;
}
.principal {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  background: #eaefef;
  max-width: 900px;
  margin: 0 auto;
}
.principal h2 {
  flex-basis: 100%;
  font-size: 1em;
  margin: 0;
  padding: 6px 5px;
  color: #fff;
  background: #027399;
}
.principal h3 {
  font-size: 1em;
}
.principal ol {
  margin-top: 8px;
}
.card {
  display: flex;
  flex: 0 1 50%;
  padding: 8px 0 10px 10px;
  border-bottom: 1px solid #ccc;
}
.card h2 {
  font-size: 16px;
}
.card p {
  font-size: 14px;
  margin: 0;
}
.thumb {
  margin-right: 5px;
}
.detalhes {
  display: flex;
  flex-direction: column;
}
.rodape {
  margin-top: 4px;
}
.livro {
  overflow: auto;
  margin: 20px 0;
}
.livro img {
  display: block;
  width: 180px;
  float: left;
  margin: 0 10px;
}
@media screen and (max-width: 600px) {
  .principal {
    flex-direction: column;
  }
}