.bs-accordion {
  .panel-heading {
    // remove the padding on the heading so we can increase the click area of the anchor
    padding: 0;
    a {
      // increase the click area of the anchor trigger to match the original .panel-heading
      display: block;
      padding: 10px 15px;
      
      // spin the chevron!
      &[aria-expanded=true] {
        .glyphicon.glyphicon-chevron-right {
          transform: rotate(90deg);
          transition: transform 350ms cubic-bezier(0.645, 0.045, 0.355, 1);
        }
      }
      .glyphicon.glyphicon-chevron-right {
        transition: transform 350ms cubic-bezier(0.645, 0.045, 0.355, 1);
      }
    }
  }
}