我的可扩展内容在 IE 上不起作用

Question

知道为什么这个代码不能在IE上工作吗?我已经测试了多个版本，据我所知:focus元素应该可以工作，但由于某种原因，当我点击它时，什么也没有发生。

.collapse {
	text-align:left;
}
.collapse > * + *{
  display:none;
  
 }
.collapse > *{
  cursor:pointer;
  }
  
.collapse:focus{
  outline:none;
}
.collapse:focus > * + *{
  display:block; 
}
.accordian-gradient {
	
	/*GRADIENT*/
	background: rgba(168,168,168,1);
/* Old Browsers */background: -moz-linear-gradient(top, rgba(168,168,168,1) 0%, rgba(203,203,203,1) 52%, rgba(234,234,234,1) 100%);
 /* FF3.6+ */background: -webkit-gradient(left top, left bottom, color-stop(0%, rgba(168,168,168,1)), color-stop(52%, rgba(203,203,203,1)), color-stop(100%, rgba(234,234,234,1)));
/* Chrome, Safari4+ */background: -webkit-linear-gradient(top, rgba(168,168,168,1) 0%, rgba(203,203,203,1) 52%, rgba(234,234,234,1) 100%);
 /* Chrome10+,Safari5.1+ */background: -o-linear-gradient(top, rgba(168,168,168,1) 0%, rgba(203,203,203,1) 52%, rgba(234,234,234,1) 100%);
 /* Opera 11.10+ */background: -ms-linear-gradient(top, rgba(168,168,168,1) 0%, rgba(203,203,203,1) 52%, rgba(234,234,234,1) 100%);
 /* IE 10+ */background: linear-gradient(to bottom, rgba(168,168,168,1) 0%, rgba(203,203,203,1) 52%, rgba(234,234,234,1) 100%);
/* W3C */filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#a8a8a8', endColorstr='#eaeaea', GradientType=0 );
/* IE6-9 */
	
	
}

 <div style="width:100%; max-width:750px; text-align:left;" class="collapse" tabindex="4">
     <div style="width:100%; max-width:750px; text-indent:10px; margin-bottom:10px; padding:5px 0px 5px 0px;" class="accordian-gradient">Question<div style="width:20%; float:right; vertical-align:middle; text-align:right; padding-right:5px;">+&nbsp;</div> </div>
     <div style="width:100%; max-width:700px; cursor:default; padding-bottom:10px; margin: 0 auto;">
     <p>Answer goes here</p>
     </div>
  </div>

有什么我可以补充的吗?我可以使用的非常有限，因为它是相当不可靠的内部样式表，没有javascript或jquery。我必须保持尽可能多的CSS内联。

谢谢

Answer 1

:focus选择器允许在接受键盘事件或其他用户输入的元素上使用。

尝试使用<button>标记。

button:focus {
  background-color: yellow;
}

<button>Expand me</button>

它似乎在Edge中工作。

编辑:

button {
  width: 100%;
  max-width: 750px;
  background-color: Transparent;
  background-repeat: no-repeat;
  border: none;
  cursor: pointer;
  overflow: hidden;
  outline: none;
}
p {
  display: none;
  background-color: aqua;
  padding: 20px;
}
button:focus p {
  display: block;
}
span {
  width: 100%;
  max-width: 750px;
  text-align: left;
}
.gradient {
  /*GRADIENT*/
  background: rgba(168, 168, 168, 1);
  /* Old Browsers */
  background: -moz-linear-gradient(top, rgba(168, 168, 168, 1) 0%, rgba(203, 203, 203, 1) 52%, rgba(234, 234, 234, 1) 100%);
  /* FF3.6+ */
  background: -webkit-gradient(left top, left bottom, color-stop(0%, rgba(168, 168, 168, 1)), color-stop(52%, rgba(203, 203, 203, 1)), color-stop(100%, rgba(234, 234, 234, 1)));
  /* Chrome, Safari4+ */
  background: -webkit-linear-gradient(top, rgba(168, 168, 168, 1) 0%, rgba(203, 203, 203, 1) 52%, rgba(234, 234, 234, 1) 100%);
  /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(top, rgba(168, 168, 168, 1) 0%, rgba(203, 203, 203, 1) 52%, rgba(234, 234, 234, 1) 100%);
  /* Opera 11.10+ */
  background: -ms-linear-gradient(top, rgba(168, 168, 168, 1) 0%, rgba(203, 203, 203, 1) 52%, rgba(234, 234, 234, 1) 100%);
  /* IE 10+ */
  background: linear-gradient(to bottom, rgba(168, 168, 168, 1) 0%, rgba(203, 203, 203, 1) 52%, rgba(234, 234, 234, 1) 100%);
  /* W3C */
  filter: progid: DXImageTransform.Microsoft.gradient( startColorstr='#a8a8a8', endColorstr='#eaeaea', GradientType=0);
  /* IE6-9 */
}

<button class="gradient">
  <span>Question</span>
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla gravida urna lacus, id tempor nulla tristique dapibus. Nulla efficitur felis iaculis mi aliquet, vel maximus dolor molestie. Nullam efficitur, urna et pretium gravida, enim justo lacinia justo, eget placerat elit nisi id sem. Pellentesque consequat pulvinar turpis, quis euismod velit. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Proin nec mattis dui, eget dapibus neque. Aliquam erat volutpat. Integer a dolor sit amet velit auctor egestas. Proin nibh felis, egestas et porta non, tincidunt non nunc. Duis aliquam, enim vulputate porta maximus, mi nunc pharetra turpis, vel vestibulum ipsum risus sit amet purus. Curabitur id bibendum ligula. Aenean ut ipsum sem. Sed placerat auctor accumsan. Morbi mollis id sapien eget ultricies. Cras tristique velit massa, a tincidunt nibh molestie commodo. Maecenas volutpat sit amet massa eu pulvinar.</p>
</button>