.bigcheckbox>input {
          -moz-appearance: none;
          -webkit-appearance: none;
          appearance: none;
          vertical-align: middle;
          outline: none;
          font-size: inherit;
          cursor: pointer;
          width: 1.0em;
          height: 1.0em;
          background: white;
          border-radius: 0.25em;
          border: 0.125em solid #555;
          position: relative;
        }
.bigcheckbox>input:checked {
    background: #adf;
}

.bigcheckbox>input:checked:after {
    content: "✔";
    position: absolute;
    font-size: 90%;
    left: 0.0625em;
    top: -0.25em;
}