html {
  font-family: sans-serif;
}

body {
  min-width: 960px;
  width: 70%;
  margin: 0 auto;
}

header {
  background-color: lime;
  height: 100px;
}

footer {
  background-color: lime;
  height: 50px;
  padding: 0 2%;
}

main {
  padding: 2%;
}

h1 {
  margin: 0;
  font-size: 4em;
  text-align: center;
  line-height: 100px;
}

p {
  font-size: 1em;
  line-height: 1.5;
}

footer p {
  line-height: 50px;
}


/* Properties for browsers with modern flexbox */

.flexbox main {
  display: flex;
}

.flexbox main div {
  padding-right: 4%;
  flex: 1;
}

.flexbox main div:last-child {
  padding-right: 0;
}


/* Fallbacks for browsers that don't support modern flexbox */

.no-flexbox main div {
  width: 22%;
  float: left;
  padding-right: 4%;
}

.no-flexbox main div:last-child {
  padding-right: 0;
}

.no-flexbox footer {
  clear: left;
}