Cislunar form elements source code is same as the Bootstrap except checkbox and radio. Read about Bootstrap Forms here .
This demo form is a modified version of this form. The checkbox and radio buttons are modified according to the theme and the source code for these looks like this:
<!-- Radio Buttons -->
<div class="form-row">
<div class="form-group col-6 col-md-3">
<div class="form-check">
<label class="form-check-label">
<input class="form-check-input" type="radio" name="gridRadios" id="gridRadios1" value="option1" checked>
<span class="cl-checkbox-input"></span>
<span class="mb-0">First radio</span>
</label>
</div>
</div>
<div class="form-group col-6 col-md-3">
<div class="form-check">
<label class="form-check-label">
<input class="form-check-input" type="radio" name="gridRadios" id="gridRadios2" value="option2">
<span class="cl-checkbox-input"></span>
<span class="mb-0">Second radio</span>
</label>
</div>
</div>
</div>
<!-- Checkbox -->
<div class="form-group">
<div class="form-check">
<label class="form-check-label">
<input class="form-check-input" type="checkbox">
<span class="cl-checkbox-input"></span>
<span class="mb-0">Check me out</span>
</label>
</div>
</div>