index.css

body {
    background: rgb(221, 220, 220);
  }
  .formBox {
      max-width: 760px;
      margin: 20px auto;
      border-radius: 4px;
      position: relative;
  }

  header {
      font-size: 48px;
      font-weight: bold;
      text-align: center;
      padding: 20px 0 25px 0;
  }

  .btn-saveData {
    margin-bottom: 5px;
    position: absolute;
    right: 0;
    top: 70px;
  }

  .card-header {
    display: flex;
    justify-content: space-between;
  }

  .list-group li {
    display: flex;
    justify-content: space-between;
  }

  .list__body {
    display: flex;
  }

  .list__checkbox {
    margin: 0 20px 0 0;
    min-width: 24px;
    max-height: 24px;
    border: solid 1px black;
    border-radius: 50%;
    text-align: center;
    cursor: pointer;
  }

  .list__delete:hover {
    color: brown;
    cursor: pointer;
  }

  .list__edit {
    height: 24px;
  }

  .hide {
    display: none !important;
  }

  .checked > .list__body > .list__checkbox {
    color: cadetblue;
    font-weight: bold;
  }

  .checked > .list__body > .list__checkbox::after {
    content: 'V';
  }

  .checked > .list__body > .list__text {
    text-decoration: line-through;
    color: rgb(211, 210, 210);
  }