body {
    margin-top: 4em;
}
#button-header {
    position: fixed;
    top: 0px;
    left: 0px;
    width: 100%;
    padding-bottom: 3px;
    padding-left: 3px;
    /* height: 3em;*/
    background-color: #aaaaaa;
    border-bottom: 1px solid #888888;
    overflow: hidden;
}

.hidden {
    display: none;
}

#message-header {
    display: none;
}

#form-data {
    /*display : block;*/
    position: fixed;
    top: 0px;
    left: 0px;
    width: 95%;
    margin-left: 2.5%;
    margin-right: 2.5%;
    margin-top: 4em;
    font-family: monospace;
    white-space: pre;
    border: 2px solid black;
    overflow: hidden;
    height: auto;
    background-color: #eeeeee;
}

form :invalid {
  box-shadow: 0 0 5px 1px red;
}

form :focus:invalid {
  outline: none;
}

form fieldset:invalid {
    box-shadow: none;
}

#button-header.valid {
    background-color: #a8e8a8;
}

body {
    margin-top: 4em;
}
#button-header {
    position: fixed;
    top: 0px;
    left: 0px;
    width: 100%;
    padding-bottom: 3px;
    padding-left: 3px;
    background-color: #aaaaaa;
    border-bottom: 1px solid #888888;
    overflow: hidden;
}

.hidden {
    display: none;
}

#message-header {
    display: none;
}

#form-data {
    position: fixed;
    top: 0px;
    left: 0px;
    width: 95%;
    margin-left: 2.5%;
    margin-right: 2.5%;
    margin-top: 4em;
    font-family: monospace;
    white-space: pre;
    border: 2px solid black;
    overflow: hidden;
    height: auto;
    background-color: #eeeeee;
}

form :invalid {
  box-shadow: 0 0 5px 1px red;
}

form :focus:invalid {
  outline: none;
}

form fieldset:invalid {
    box-shadow: none;
}

#button-header.valid {
    background-color: #a8e8a8;
}

Remove legacy commented out CSS
Remove legacy commented out CSS

These commented out values are no longer needed.
