body {
  font: 18px/1.5 sans-serif;
  padding: 1rem;
}

dt {
  font-weight: bold;
}

dl {
  margin-bottom: 50px;
}

#bug:target {
  outline: 4px solid #ccc;
}

/**
 * tab panel widget
 */
.tabPanel-widget {
  position: relative;  /* containing block for headings (top:0) */
  background: #999;
}

/**
 * because labels come first in source order - we use z-index to move them in front of the headings
 */
.tabPanel-widget > label {
  position: absolute;
  z-index: 1;
}

/**
 * labels and headings must share same values so grouping declarations in this rule prevents async edits (risk of breakage)
 * line-height == height -> vertical centering
 * the width dictates the offset for all headings but the first one: left offset = width * number of previous heading(s)
 * note that width and offset of label/heading pair can be customized if necessary
 */

.tabPanel-widget > label,
.tabPanel-widget > h2 {
  font-size: 1.1em;
  width: 9em;
  height: 2em;
  line-height: 2em;
}

/**
 * position:relative is for the markers (the down arrow in tabs)
 */
.tabPanel-widget > h2 {
  position: relative;
  margin: 0;
  text-align: center;
  background: #999;
  color: #fff;
}

.tabPanel-widget > label {
  border-right: 1px solid #fff;  
}

/**
 * all first level labels and headings after the very first ones 
 */
.tabPanel-widget > label ~ label,
.tabPanel-widget > h2 ~ h2 {
  position: absolute;
  top: 0;
}


/**
 * We target all the label/heading pairs
 * we increment the :nth-child() params by 4 as well as the left value (according to "tab" width)
 */

.tabPanel-widget label:nth-child(1),
.tabPanel-widget h2:nth-child(3) {
  left: 0em;
}

.tabPanel-widget label:nth-child(5),
.tabPanel-widget h2:nth-child(7) {
  left: 9em;
}

.tabPanel-widget label:nth-child(9),
.tabPanel-widget h2:nth-child(11) {
  left: 18em;
}

/**
 * we visually hide all the panels
 * https://developer.yahoo.com/blogs/ydn/clip-hidden-content-better-accessibility-53456.html
 */
.tabPanel-widget input + h2 + div {
  position: absolute !important;
  clip: rect(1px, 1px, 1px, 1px);
  padding:0 !important;
  border:0 !important;
  height: 1px !important; 
  width: 1px !important; 
  overflow: hidden;
}
/**
 * we reveal a panel depending on which control is selected 
 */
.tabPanel-widget input:checked + h2 + div {
  position: static !important;
  padding: 1em !important;
  height: auto !important; 
  width: auto !important; 
}

/**
 * shows a hand cursor only to pointing device users
 */
.tabPanel-widget label:hover {
  cursor: pointer;
}

.tabPanel-widget > div {
  background: #f0f0f0;
  padding: 1em;
}

/**
 * we hide radio buttons and also remove them from the flow
 */
.tabPanel-widget input[name="tabs"] {
  opacity: 0;
  position: absolute;
}


/** 
 * this is to style the tabs when they get focus (visual cue)
 */

.tabPanel-widget input[name="tabs"]:focus + h2 {
  outline: 1px dotted #000;
  outline-offset: 10px;
}


/**
 * reset of the above within the tab panel (for pointing-device users)
 */
.tabPanel-widget:hover h2 {
  outline: none !important;
}

/**
 * visual cue of the selection
 */
.tabPanel-widget input[name="tabs"]:checked + h2 {
  background: #333;
}

/**
 * the marker for tabs (down arrow)
 */
.tabPanel-widget input[name="tabs"]:checked + h2:after {
  content: '';
  margin: auto;
  position: absolute;
  bottom: -10px;
  left: 0;
  right: 0;
  width: 0;
  height: 0;
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-top: 10px solid #333;
}

/**
 * Make it plain/simple below 45em (stack everything)
 */
@media screen and (max-width: 45em) {
  
  /* hide unecessary label/control pairs */
  .tabPanel-widget label,
  .tabPanel-widget input[name="tabs"] {
    display: none;
  }
  
  /* reveal all panels */
  .tabPanel-widget > input + h2 + div {
    display: block !important;
    position: static !important;
    padding: 1em !important;
    height: auto !important; 
    width: auto !important; 
  }
  
  /* "unstyle" the heading */
  .tabPanel-widget h2 {
    width: auto;
    position: static !important;
    background: #999 !important;
  }
  
  /* "kill" the marker */
  .tabPanel-widget h2:after {
    display: none !important;
  }

}