Last child does not take effect

Write css When I met a magical problem ,first-child take effect 、 but last-child invalid .
The observation style and code structure are as follows ：

<div class="c0">
   <div class="c1"></div>
   <div class="c1"></div>
   <div class="loading"></div>
</div>

.c0 .c1:last-child {
    
  padding: 10px;
}

as a result of ,
.c0 .c1:first-child , This selector finds c0 The next one is really c1, Match to the first line , take effect .
.c0 .c1:last-child, The effective condition of this selector is c0 The last child element must be c1, But the actual HTML In structure , The last one is loading, So it didn't take effect .

The solution is 2 individual ：

1、 Guarantee c0 Is a new nest div Last element of . But it's hard to do , The actual situation is always mixed with various types of elements .
2、 Use .c0 .c1:last-of-type

Reference documents ：【CSS】 solve first-child、last-child No effect