section {
  background-repeat:no-repeat;
  background-size:cover;
  min-height:100vh;
}

.blockdiv {
  margin-top:10px;
  margin:auto;
  margin-top:10px;
  padding:10px;
  max-width:750px;
}

.dark {
  background-color:rgba(200,200,200,0.65);
}

.text-center {
  align-content:center;
}

.centertext {
  text-align:center;
  padding-left:10%;
  padding-right:10%;
}

.block {
}