為什么按照老師寫(xiě)的代碼，頂部的三角和三角里面的圖顏色變了，H2 和P沒(méi)有變顏色呢

.st-color{?background:#fa96b5;}
.st-color?.st-desc{?background:#fff;}
.st-color?[data-icon]:after{?color:#fa96b5;}
.st-color?h2{?color:#fff;?text-shadow:1px?1px?1px?rgba(0,0,0.1)}
.st-color?p{?color:#fff;}

<div?class="st-scroll">
??????<section?class="st-panel"?id="?st-panel-1">
????????<div?class="st-desc"?data-icon="H"></div>
????????<h2>Serendipity</h2>
????????<p>中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中</p>
??????</section>
??????<section?class="st-panel?st-color"?id="?st-panel-2">
????????<div?class="st-desc"?data-icon="2"></div>
????????<h2>Happiness</h2>
????????<p>中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中</p>
??????</section>
??????<section?class="st-panel"?id="?st-panel-3">
????????<div?class="st-desc"?data-icon="B"></div>
????????<h2>Tranquillity</h2>
????????<p>中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中</p>
??????</section>
??????<section?class="st-panel?st-color"?id="?st-panel-4">
????????<div?class="st-desc"?data-icon="X"></div>
????????<h2>Positivity</h2>
????????<p>中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中</p>
??????</section>
??????<section?class="st-panel"?id="?st-panel-5">
????????<div?class="st-desc"?data-icon="C"></div>
????????<h2>Passion</h2>
????????<p>中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中中</p>
??????</section>
????</div>