<!DOCTYPE html>
<html>
<head>
<title>Заголовок документа</title>
<style>
.example {
margin: 40px auto;
max-width: 400px;
}
label,
button {
display: block;
width: 100%;
margin-bottom: 1.5em;
}
input,
select,
button {
padding: .4em 1em;
}
input,
select {
border: 1px solid #666666;
}
input:optional,
select:optional {
background-color: #eeeeee;
color: #666666;
opacity: 0.5;
transition: .3s;
}
input:optional:hover,
select:optional:hover {
opacity: 1;
}
input:required,