如何將css調用到div類的內部div類？

Question

我嘗試將css調用到div類內部div類中。請解決我的代碼？

HTML代碼：

<div class="underpost_3c_head"> 
    <div class="underpost_3c_head_title">hhh1 </div> 

    <div class="underpost_2nd_page_head_title"> 
     <div class="2nd_page_head_result">hhh</div> 
     <div class="2nd_page_head_result">hhh</div> 
     <div class="2nd_page_head_result">hhh</div> 
     <div class="2nd_page_head_result">hhh</div> 
    </div> 

    <div class="underpost_3rd_page_head_title"> 
     <div class="3rd_page_head_result">hhh</div> 
     <div class="3rd_page_head_result">hhh</div> 
     <div class="3rd_page_head_result">hhh</div> 
     <div class="3rd_page_head_result">hhh</div> 
    </div> 

</div> 

---

我如何可以選擇所有類？ 我嘗試：

.2nd_page_head_result { 
    width: 110px; 
    padding-left:5px; 
} 

和

div.2nd_page_head_result { 
    padding-left:5px; 
} 

但它不工作。請幫我解決這個問題。

Answer 1

您不能使用數字開始類名和/或ID。

.nd_page_head_result { 
 
    width: 110px; 
 
    padding-left: 5px; 
 
    background: wheat; 
 
}

<div class="underpost_3c_head"> 
 
    <div class="underpost_3c_head_title">hhh1</div> 
 

 
    <div class="underpost_2nd_page_head_title"> 
 
    <div class="nd_page_head_result">hhh</div> 
 
    <div class="nd_page_head_result">hhh</div> 
 
    <div class="nd_page_head_result">hhh</div> 
 
    <div class="nd_page_head_result">hhh</div> 
 
    </div> 
 

 
    <div class="underpost_3rd_page_head_title"> 
 
    <div class="3rd_page_head_result">hhh</div> 
 
    <div class="3rd_page_head_result">hhh</div> 
 
    <div class="3rd_page_head_result">hhh</div> 
 
    <div class="3rd_page_head_result">hhh</div> 
 
    </div> 
 

 
</div>

有解決的辦法，但是：

[class="3rd_page_head_result"] {color: red;} 

https://benfrain.com/when-and-where-you-can-use-numbers-in-id-and-class-names/