html，css设置了纯黑背景之后，其他文本内容都不显示了

Question

结果出来背景全黑，啥也没有

.section-content-container hgroup {
    margin: auto;
    text-align: center;
    letter-spacing: 2px;
    color: white;
    position: relative;
    right: -100%;
    opacity:1;   
}

.active .section-content-container hgroup {
    right: 0;
    opacity:1;
    color: white;
}

.section-content-container hgroup h2 {
    text-transform: uppercase;
    font-weight: normal;
    color: white;
}
.hgrouptext{
    color:white !important;
}
.section-content-container hgroup h3 {

    margin-top: 10px;
    color: white;
}

.white .section-content-container hgroup h3 {
    color:white;
}

<div class="section-content-container" >
                    <hgroup>
                        <h2 style="color:#fff;">关于我们</h2>
                        <h3 style="color:#fff;">ABOUT US</h3>
                    </hgroup>
                </div>

Answer 1

这是设置背景的句子