body{
  font:20px/1.1em arial, sans-serif;
  background:lightgray;
}


#grille{
  display: flex;
  width: 100%;
  flex-wrap: wrap;
}

.element{
  display: block;
  background-color: red;
  width: 100px;
  height: 100px;
  margin: 10px;
}



/*Css source permettant de rajouter font, variable etc.*/