Cannot click and write in fields

When I add this CSS to my form, the input fields become non-clickable…

#book-request-form {
padding: 5px;
width: auto;
margin: 20px auto;
}

#book-request-1 {
width: 25%;
float: left;
padding: 5px 15px;
}

#book-request-2 {
width: 25%;
float: left;
padding: 5px 15px;
}

#book-request-3 {
width: 25%;
float: left;
padding: 5px 15px;
}

#book-request-4 {
width: 25%;
float: left;
padding: 5px 15px;
}

What is wrong? https://elefanthue.dk/contact/