.secao{
  float: left;
  width: 33%;
}
.mini{
  float: left;
  width: 50%;
}
.container{
  margin: 0 auto;
  max-width: 1200px;
}
.logo,
.secao {
  padding: 0 1%;
}
img { /*Usar o max-width:100% nas imagens vai impedi-las de estragar o design*/
  max-width: 100%;
}
.logo,
.busca,
.barra-nav,
.menu-principal {
    display: inline-block;
    vertical-align: middle;
}
.menu-principal li {
    float: left;
}
header {
  padding: 0.5em 0;
}
.destaques {
  margin-top: 1em;
}
.barra-nav {
  background: #f0f0f0;
  padding: 1em;
  margin: 0;

  height: 100%;
  width: 90%;
  max-width: 320px;

  position: fixed;
  z-index: 1;
  top: 0;
  left: -90%;

  transition: left 0.3s ease-out;
}

.menu-ativo .barra-nav{
  left: 0;

}

@media (min-width: 600px) {
  html {
      font-size: 1.125em;
  }
  .secao {
      width: 50%;
      float: left;
  }
}

@media (min-width: 1000px) {
  html {
      font-size: 1.25em;
  }
  .secao {
      width: 33.333%;
  }
}

@media (max-width: 600px) {
.barra-nav {
    background: #f0f0f0;
    padding: 1em;
    margin: 0;

    height: 100%;
    width: 90%;
    max-width: 320px;

    position: fixed;
    z-index: 1;
    top: 0;
    left: -90%;

    transition: left 0.3s ease-out;
}
.menu-ativo .barra-nav {
    left: 0;
}
.menu-principal li {
    padding: 1em 0;
    width: 100%;
}
.menu-ativo:after {
      content: "";
      display: block;

      position: fixed;
      top: 0;
      left: 0;
      bottom: 0;
      right: 0;

      background: rgba(0,0,0,0.4);
  }
}

@media not all and (max-width: 600px) {
  .menu-abrir,
  .menu-fechar {
      display: none;
  }
}