* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: sans-serif;
  scroll-behavior: smooth;
}

#topBtn {
display: none;
color: #fff;
font-size: 3em;
background-color: #000;
width: 50px;
height: 50px;
text-align: center;
border-radius: 4px;
position: fixed;
bottom: 30px;
right: 30px;
transition: background-color 0.3s, opacity 0.5s, visibility 0.5s;
}

#topBtn:hover {
cursor: pointer;
background-color: gray;
}

nav {
  background-color: #333;
  overflow: hidden;
}

nav .btNav {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
  background: #333;
}

button {
cursor:pointer;
}

article {
text-align: center;
}

#bilde {
max-width: 450px;
display: inline-block;
}


#b1, #b2, #b3 {
display: none;
}

.svar {
text-align: center;
}