* {
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
}

body {
  background: #222;
  color: #C0FF00;
  font-family: Helvetica Neue,Helvetica,Arial,sans-serif;

  display: flex;
  align-items: center;
  justify-content: center;
}

a {
  color: #C0FF00;
}

section {
  max-width: 50%;
  text-align: center;
}

h1 {
  font-size: 5em;
  font-weight: 600;
  letter-spacing: 0.02em
}

ul {
  list-style-type: none;
  display: flex;
  margin: 2em 0;
}

li {
  flex-grow: 1;
}

li a {
  display: block;
  width: 2em;
  height: 2em;
  background-repeat: no-repeat;
  background-size: 100%;
  text-indent: -9999em;
  margin: 0 auto;
  opacity: .3;
  transition: opacity .25s ease-in-out;
}

li a:hover {
  opacity: .7;
}

.twitter {
  background-image: url(img/social-1_logo-twitter.svg);
}
.flickr {
  background-image: url(img/social-1_logo-flickr.svg);
}
.github {
  background-image: url(img/social-1_logo-github.svg);
}
.instagram {
  background-image: url(img/social-1_logo-instagram.svg);
}
.email {
  background-image: url(img/email.svg);
}