body{
  background: url("https://wallpapercave.com/wp/NCJgtUD.jpg");
  text-align: center;
}

form{
  background: linear-gradient(90deg, rgb(0, 255, 0), rgb(255, 0, 0), rgb(0, 0, 255));
  opacity: 0.75;
  text-align: left;
  margin: auto;
  padding: 20px;
  width: 50%;
  max-width: 500px;
  min-width: 300px;
}

label, input, select, textarea{
  display: block;
  margin: 10px 0;
  width: 100%;
}


input[type="radio"], input[type="checkbox"]{
  display: inline;
  margin: auto 5px;
  width: 25px;
}