how to hide circle in radio button in html code example

Example: hide radio button circle

<style>
.opacity {
	position: absolute;
	opacity: 0;
	width: 0;
}
input[type=checkbox]+label {
	font-weight: normal;
}
input[type=checkbox]:checked+label {
	font-weight: bold;
}
input[type=checkbox]:focus+label {
	border: 1px dotted #000;
}
</style>

<input class="opacity" type="checkbox" id="checkbox1">
<label for="checkbox1">Checkbox 1check</label>
<br />
<input class="opacity" type="checkbox" id="checkbox2">
<label for="checkbox2">Checkbox 2check</label>