<label for="name">Name (4 to 8 characters):</label>

<input type="text" id="name" name="name" required minlength="4" maxlength="8" size="10" />

label {
  display: block;
  font:
    1rem 'Fira Sans',
    sans-serif;
}

input,
label {
  margin: 0.4rem 0;
}