CSS-custom-radio-btn.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            margin-top: 360px;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .container {
            padding-left: 30px;
            margin-bottom: 12px;
            position: relative;
        }

        .container input {
            display: none;
        }

        .checkmark {
            width: 25px;
            height: 25px;
            background: chartreuse;
            position: absolute;
            top: 0;
            left: 0;
            border-radius: 50%;
            cursor: pointer;
        }

        .container:hover input~.checkmark {
            background-color: cornflowerblue;
        }

        .container input:checked~.checkmark {
            background: crimson;
        }

        .checkmark::after {
            content: " ";
            position: absolute;
            display: none;
        }

        .container input:checked~.checkmark:after {
            display: block;
        }

        .container .checkmark::after {
            top: 9px;
            left: 9px;
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: white;
        }
    </style>
</head>

<body>
    <label class="container" for="radio">
        <input type="checkbox" name="radio" id="radio" checked="checked">
        <span class="checkmark"></span>
        One
    </label>

</body>

</html>