input:required {
  outline: 1px red solid;
  color:red;
}

← autofocus <input type=text autofocus required>
<input type=text list=titles>
  <option label=Mr value=Mr>
  <option label=Ms value=Ms>
  <option label=Prof value="Mad Professor">
<input type=number min=18 max=100 value=40>
<input type=email required>
<input type=date>
1 <input type=range min=1 max=10>