JSFiddle - React, Tailwind, and code Playground
by Adrià Vilanova Martínez
HTML
<form action="http://example.com">
<input type="number" min="1" max="10" step="0.5" list="possibleanswers" name="num" required>
<datalist id="possibleanswers">
<option value="9">Solución 1</option>
<option value="5.5">Solución 2</option>
</datalist>
<input type="submit">
</form>
CSS
input[type="number"] {
width: 100px;
}
input[type="number"]:valid {
border: solid 1px green;
outline-color: green;
}
input[type="number"]:invalid {
border: solid 1px red;
outline-color: red;
}