CSS binary number encoder

input:not(:checked) + input:not(:checked) + input:not(:checked) + input:checked + 
  div:before {
    content: "1";
}
input:not(:checked) + input:not(:checked) + input:checked + input:not(:checked) + 
  div:before {
    content: "2";
}
input:not(:checked) + input:not(:checked) + input:checked + input:checked + 
  div:before {
    content: "3";
}
input:not(:checked) + input:checked + input:not(:checked) + input:not(:checked) + 
  div:before {
    content: "4";
}
input:not(:checked) + input:checked + input:not(:checked) + input:checked + 
  div:before {
    content: "5";
}
input:not(:checked) + input:checked + input:checked + input:not(:checked) + 
  div:before {
    content: "6";
}
input:not(:checked) + input:checked + input:checked + input:checked + 
  div:before {
    content: "7";
}
input:checked + input:not(:checked) + input:not(:checked) + input:not(:checked) + 
  div:before {
    content: "8";
}