h1 { font-size: 50px; }
body { background-color: #000; font: 18px Helvetica, sans-serif; font-weight: 300; line-height: 1.5rem; color: #fff; margin: 2em auto;}
article { display: block; text-align: left; max-width: 480px ; margin: 2em auto; padding: 0 2em;}
a { color: #eee; text-decoration: none; }
a:hover, .pure-white:hover { color: #333; text-decoration: none; }

.logo {display: block; max-width: 350px; margin: 0 auto }

.center {text-align: center; }

.pure-white {color: #fff; }

.parent {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
  margin: 0 2em;
}

.child {
  min-width: 310px;
}