select-button.css

.select-button {
  position: relative;
  display: inline-block;
  box-sizing: border-box;
  display: inline-block;
}

  .select-button_stretched {
    width: 100%;
  }

  .select-button__select {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    rigth: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none; 
    opacity: 0;
  }