body {
  font-family: Arial, sans-serif;
  font-size: 16px;
  background-color: lightgreen;
  line-height: 50px;
}

.container {
  margin: 50px auto;
  padding: 30px 50px;
  max-width: 350px;
  box-shadow: 0 2px 4px;
  background-color: white;
}

h1 {
  text-align: center;
  color: darkgreen;
}

input:focus,
textarea:focus {
  border-color: blue;
}

input:invalid,
select:invalid,
textarea:invalid {
  border-color: red;
}

input:valid,
select:valid,
textarea:valid {
  border-color: green;
}

button {
  width: 100%;
  padding: 10px;
  background-color: green;
  color: white;
  border: none;
  border-radius: 4px;
  font-size: 16px;
  cursor: pointer;
}

button:hover {
  background-color: lightblue;
}

.radio-group input[type="radio"]:checked {
  border-color: green;
  background-color: green;
  box-shadow: 3px 3px 2px green;
}

.radio-group input[type="radio"]:checked + label {
  font-weight: bold;
  color: green;
}

input:first-of-type {
  border-radius: 4px;
}