body {
  background-color:dimgray;
  font-family: Mynerve;
  line-height: 20px;
  font-size:17px;
  background-image: url("images/briefbgbg.jpg");
  background-repeat: no-repeat;
  background-position: top;
  background-attachment: fixed;
  background-size: cover;
}

ul {
  list-style-type: none;
  padding: 0px;
  margin:0;
  overflow: hidden;
  background-image: url("images/briefterug.png");
  background-repeat: no-repeat;
  width:135px;
  height:101px;
  position: fixed;
  font-family: Georgia;
}

li {
  padding:5px;
}

li a {
  display: block;
  color: dimgray;
  font-weight: 600;
  font-size:20px;
  text-align: center;
  padding: 10px 10px;
  text-decoration: none;
}

li a:hover {
  color: black;
}



input {
  display: none;
}

.brief {
  margin-left: auto;
  margin-right:auto;
  width: fit-content;
  filter: drop-shadow(4px 4px 10px rgba(0,0,0,0.5));
}

.card {
  transition: all 1s ease;
  transform-style: preserve-3d;
  cursor: pointer;
  position: relative;
  background-image:url("images/briefbg.png");
  height:819px;
  width:579px;
  background-repeat: no-repeat;
  box-sizing: border-box; 
  
}

#card:checked + label .card {
  transform: perspective(2000px) rotateY(-180deg);
}

.kantA {
  position: absolute;
  padding: 30px;
 -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  transform: rotateX(0deg);
}

.kantB {
  position: absolute;
  background-image: url("images/briefbgback.png");
  height:819px;
  width:579px;
  background-repeat: no-repeat;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  transform: rotateY(180deg);
}

.contentsB {
  padding:30px;
}



.voor_brief {
  width:600px;
  margin-left:auto;
  margin-right: auto;
  background-color: rgb(205, 202, 195);
  padding: 40px;
  font-family: Georgia;
  text-align: center;
  color: #363636;
  font-weight: 500;
  font-size:20px;
  border-radius: 5px;
  box-shadow: 0px 0px 15px black;
  position: relative;
}