body {background-color: rgba(255,255,255);
    counter-reset : numexo;
    counter-reset : numdef;
}

.def {
  counter-increment:numdef;
  border-width:4 px;
  border-style:double;
  border-color:black;
  margin-bottom: 1em;
}
.def:before { 
  content : "Définition " counter(numdef) ": ";
}
.exo {
  counter-increment:numexo;
  border-width:4 px;
  border-style:double;
  border-color:black;
  margin-bottom: 1em;
}
.exo:before {
    content : "Exercice " counter(numexo) ". ";
}

h6{
  font-size: larger;
}

.tile{
 border-radius:0;
}
.tile{
  background-color: white;
   border: 5px solid rgb(200,200,200);
   border-radius: 25px;
}