Recomended styles for improving checkboxes

checkbox-styles.css

.checkbox {
  label {
    position: relative;
    &:before {
      content: 0;
      display: block;
      font-family: 'FontAwesome';
      font-size: 0;
      line-height: 0;
      text-rendering: auto;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
      position: absolute;
      top: 0;
      left: 0;
    }  
  }
  input {
    //estilos aquí
  }
  input:checked + label {
    &:before {
      content: "\f14a";
    }
  }
}