Result

CSS ScanでCSSでスタイリングされた実用的でユニークなチェックボックスが沢山紹介されています。

どれもクリックだけでコピー可能で、CSSとHTMLがセットになったコードを発行しているのでペーストするだけで実装できるようになっています。

全てJavaScript不要で実装可能です。

css

.checkbox-wrapper-11 {
    --text: #414856;
    --check: #4F29F0;
    --disabled: #C3C8DE;
    --border-radius: 10px;
    border-radius: var(--border-radius);
    position: relative;
    padding: 5px;
    display: grid;
    grid-template-columns: 30px auto;
    align-items: center;
  }
  .checkbox-wrapper-11 label {
    color: var(--text);
    position: relative;
    cursor: pointer;
    display: grid;
    align-items: center;
    width: -webkit-fit-content;
    width: -moz-fit-content;
    width: fit-content;
    transition: color 0.3s ease;
  }
  .checkbox-wrapper-11 label::before,
  .checkbox-wrapper-11 label::after {
    content: "";
    position: absolute;
  }
  .checkbox-wrapper-11 label::before {
    height: 2px;
    width: 8px;
    left: -27px;
    background: var(--check);
    border-radius: 2px;
    transition: background 0.3s ease;
  }
  .checkbox-wrapper-11 label:after {
    height: 4px;
    width: 4px;
    top: 8px;
    left: -25px;
    border-radius: 50%;
  }
  .checkbox-wrapper-11 input[type=checkbox] {
    -webkit-appearance: none;
    -moz-appearance: none;
    position: relative;
    height: 15px;
    width: 15px;
    outline: none;
    border: 0;
    margin: 0 15px 0 0;
    cursor: pointer;
    background: var(--background);
    display: grid;
    align-items: center;
  }
  .checkbox-wrapper-11 input[type=checkbox]::before, .checkbox-wrapper-11 input[type=checkbox]::after {
    content: "";
    position: absolute;
    height: 2px;
    top: auto;
    background: var(--check);
    border-radius: 2px;
  }
  .checkbox-wrapper-11 input[type=checkbox]::before {
    width: 0px;
    right: 60%;
    transform-origin: right bottom;
  }
  .checkbox-wrapper-11 input[type=checkbox]::after {
    width: 0px;
    left: 40%;
    transform-origin: left bottom;
  }
  .checkbox-wrapper-11 input[type=checkbox]:checked::before {
    -webkit-animation: check-01-11 0.4s ease forwards;
            animation: check-01-11 0.4s ease forwards;
  }
  .checkbox-wrapper-11 input[type=checkbox]:checked::after {
    -webkit-animation: check-02-11 0.4s ease forwards;
            animation: check-02-11 0.4s ease forwards;
  }
  .checkbox-wrapper-11 input[type=checkbox]:checked + label {
    color: var(--disabled);
    -webkit-animation: move-11 0.3s ease 0.1s forwards;
            animation: move-11 0.3s ease 0.1s forwards;
  }
  .checkbox-wrapper-11 input[type=checkbox]:checked + label::before {
    background: var(--disabled);
    -webkit-animation: slice-11 0.4s ease forwards;
            animation: slice-11 0.4s ease forwards;
  }
  .checkbox-wrapper-11 input[type=checkbox]:checked + label::after {
    -webkit-animation: firework-11 0.5s ease forwards 0.1s;
            animation: firework-11 0.5s ease forwards 0.1s;
  }

  @-webkit-keyframes move-11 {
    50% {
      padding-left: 8px;
      padding-right: 0px;
    }
    100% {
      padding-right: 4px;
    }
  }

  @keyframes move-11 {
    50% {
      padding-left: 8px;
      padding-right: 0px;
    }
    100% {
      padding-right: 4px;
    }
  }
  @-webkit-keyframes slice-11 {
    60% {
      width: 100%;
      left: 4px;
    }
    100% {
      width: 100%;
      left: -2px;
      padding-left: 0;
    }
  }
  @keyframes slice-11 {
    60% {
      width: 100%;
      left: 4px;
    }
    100% {
      width: 100%;
      left: -2px;
      padding-left: 0;
    }
  }
  @-webkit-keyframes check-01-11 {
    0% {
      width: 4px;
      top: auto;
      transform: rotate(0);
    }
    50% {
      width: 0px;
      top: auto;
      transform: rotate(0);
    }
    51% {
      width: 0px;
      top: 8px;
      transform: rotate(45deg);
    }
    100% {
      width: 5px;
      top: 8px;
      transform: rotate(45deg);
    }
  }
  @keyframes check-01-11 {
    0% {
      width: 4px;
      top: auto;
      transform: rotate(0);
    }
    50% {
      width: 0px;
      top: auto;
      transform: rotate(0);
    }
    51% {
      width: 0px;
      top: 8px;
      transform: rotate(45deg);
    }
    100% {
      width: 5px;
      top: 8px;
      transform: rotate(45deg);
    }
  }
  @-webkit-keyframes check-02-11 {
    0% {
      width: 4px;
      top: auto;
      transform: rotate(0);
    }
    50% {
      width: 0px;
      top: auto;
      transform: rotate(0);
    }
    51% {
      width: 0px;
      top: 8px;
      transform: rotate(-45deg);
    }
    100% {
      width: 10px;
      top: 8px;
      transform: rotate(-45deg);
    }
  }
  @keyframes check-02-11 {
    0% {
      width: 4px;
      top: auto;
      transform: rotate(0);
    }
    50% {
      width: 0px;
      top: auto;
      transform: rotate(0);
    }
    51% {
      width: 0px;
      top: 8px;
      transform: rotate(-45deg);
    }
    100% {
      width: 10px;
      top: 8px;
      transform: rotate(-45deg);
    }
  }
  @-webkit-keyframes firework-11 {
    0% {
      opacity: 1;
      box-shadow: 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0;
    }
    30% {
      opacity: 1;
    }
    100% {
      opacity: 0;
      box-shadow: 0 -15px 0 0px #4F29F0, 14px -8px 0 0px #4F29F0, 14px 8px 0 0px #4F29F0, 0 15px 0 0px #4F29F0, -14px 8px 0 0px #4F29F0, -14px -8px 0 0px #4F29F0;
    }
  }
  @keyframes firework-11 {
    0% {
      opacity: 1;
      box-shadow: 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0, 0 0 0 -2px #4F29F0;
    }
    30% {
      opacity: 1;
    }
    100% {
      opacity: 0;
      box-shadow: 0 -15px 0 0px #4F29F0, 14px -8px 0 0px #4F29F0, 14px 8px 0 0px #4F29F0, 0 15px 0 0px #4F29F0, -14px 8px 0 0px #4F29F0, -14px -8px 0 0px #4F29F0;
    }
  }

1つの例です。Todoに使えるチェックボックス。チェックを入れると同時に線を入れてくれます。

html

<div class="checkbox-wrapper-11">
  <input id="02-11" type="checkbox" name="r" value="2">
  <label for="02-11">To-do</label>
</div>

via

Beautiful CSS checkboxes examples

ブックマークして使ってねとの事です。