5.1.5 forms.base.input-radio Radio buttons

Toggle example guides Toggle HTML markup

If an <input> element has the type='radio' attribute set, the form field is displayed as a radio button.

It is recommended that you do not style checkbox and radio inputs as Firefox's implementation does not respect box-sizing, padding, or width.

Example
Markup: base/forms/forms-input-radio.twig 
<div>
  <label><input type="radio" class="{{modifier_class}}" value="option1" name="example-radio" checked> Option one</label>
</div>

<div>
  <label><input type="radio" class="{{modifier_class}}" value="option2" name="example-radio"> Option two</label>
</div>

<div>
  <label><input type="radio" class="{{modifier_class}}" value="option3" name="example-radio" disabled> Option three is disabled</label>
</div>
Source: base/forms/_forms.scss, line 161