/* Reset et Déco */

html {
  font-size: 62.5%;
  box-sizing: border-box;
}

* {
  box-sizing: inherit;
}

body {
  max-width: 80%;
  margin: 2rem auto;
  background: #fff;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 1.8rem;
  line-height: 1.5;
}

h1 {
  margin-top: 20px;
  margin-bottom: 40px;
  color: #345;
  text-shadow: 1px 1px 1px #fff;
  font-weight: normal;
}

a {
  display: block;
  padding: 6px 12px;
  color: #fff;
  text-decoration: none;
  background: #999;
}


/* Correction */

div {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: .5rem 2rem;
  grid-auto-flow: dense;
}

[href$=".doc"] {
  grid-column: 1;
  background: orange;
}

[href$=".xls"] {
  grid-column: 2;
  background: olivedrab;
}

[href$=".pdf"] {
  grid-column: 3;
  background: hotpink;
}


/* BONUS étiquettes */


a::before {
  font-size: .7em;
  display: inline-block;
  padding: 8px;
  border-radius: 6px;
  background: #333;
  transform: translate(-1.5em, -1em);
}
[href$=".doc"]::before {
  content: ".doc";
}
[href$=".xls"]::before {
  content: ".xls";
}
[href$=".pdf"]::before {
  content: ".pdf";
}

[href$=".doc"] ~ [href$=".doc"]::before,
[href$=".xls"] ~ [href$=".xls"]::before,
[href$=".pdf"] ~ [href$=".pdf"]::before {
  visibility: hidden;
}