<div class="cp_ipradio04">
  <input type="radio" name="cpipr04" id="b_rb1" value="1">
  <label for="b_rb1">ネコ</label>
  <input type="radio" name="cpipr04" id="b_rb2" value="2">
  <label for="b_rb2">イヌ</label>
  <input type="radio" name="cpipr04" id="b_rb3" value="3" checked>
  <label for="b_rb3">ウサギ</label>
</div>

.cp_ipradio04 {
  width: 60%;
  margin: 2em auto;
}
/*デフォルトのラジオボタンの設定*/
.cp_ipradio04 input[type='radio'] {
  display: none;
}
/*通常時のラジオボタンの設定*/
.cp_ipradio04 label {
  position: relative;
  display: flex;
  align-items: center;
  margin-bottom: 10px;
  cursor: pointer;
}
.cp_ipradio04 input[type='radio'] + label:before,
.cp_ipradio04 input[type='radio'] + label:after {
  position: absolute;
  content: '';
}
/*スイッチのベース*/
.cp_ipradio04 input[type='radio'] + label:before {
  right: 0;
  width: 30px;
  height: 15px;
  background: #ffffff;
  border: 1px solid #e4e3e1;
  border-radius: 15px;
}
/*スイッチの●*/
.cp_ipradio04 input[type='radio'] + label:after {
  right: 15px;
  width: 15px;
  height: 15px;
  background: #bdbdbd;
  border-radius: 50%;
  transition: all 200ms ease-out;
}
/*checked時の色と位置の設定*/
.cp_ipradio04 input[type='radio']:checked + label:after {
  right: 0;
  background: #da3c41;
}