style disabled button

button:disabled,
button[disabled]{
  border: 1px solid #999999;
  background-color: #cccccc;
  color: #666666;
}<button id="btnSubmit" class="btn-disable">Click</button>

<style type="text/css">
    .btn-disable
        {
        cursor: not-allowed;
        pointer-events: none;

        /*Button disabled - CSS color class*/
        color: #c0c0c0;
        background-color: #ffffff;

        }
</style>