.my_form_class select {
  display: block;
  font-size: 16px;
  font-family: sans-serif;
  font-weight: normal;
  color: #444;
  line-height: 1.3;
  padding: .6em 1.4em .5em .8em;
  width: 100%;
  max-width: 100%; /* useful when width is set to anything other than 100% */
  box-sizing: border-box;
  margin: 0;
  border: 1px solid #aaa;
  box-shadow: 0 1px 0 1px rgba(0,0,0,.04);
  border-radius: .5em;
  -moz-appearance: none;
  -webkit-appearance: none;
  appearance: none;
  background-color: #fff;
}