Why does it have no effect when the mouse slides over the a in li? _html/css_WEB-ITnose

html code:

Information Code in css file:
li.big{
float:none;
font-weight:normal;
padding:5px 20px 5px 20px;
text-align:center ;
margin-left:50px;
margin-top:20px;
font-size:20px;
}
.cho{
display:block;
width: 80px;
height:30px;
font-family:'SimHei';
color:#2f2f2f;
padding-top:5px;
}
a.chodet : hover{
color:white;
}
li.big : hover{
width:80px;
height:30px;
border-radius:8px;
border:0;
background:#ff9138;
}

Reply to discussion (solution)

li.big:hover{
Remove the spaces

The spaces should not matter.
li.big : hover{
width:80px;
height:30px;
border-radius:8px;
border:0;
background:#ff9138;
}
Please try to modify this paragraph

No. 1: The space between li.big: hover and a.chodet: hover must be removed before hover can take effect
No. 2: You To make the hover of the a tag take effect, a.chodet:hover should be changed to a.cho:hover
3rd: In order to implement an effect event (hover adds background and changes color), you use two events, resource efficiency Neither is optimal. It’s best to just add a hover to the a tag.

Both a and hover must be added with display:block;.

What a mess. . . Is it written according to standards?

Add display:block to the a tag! ! !

Thank you very much for taking the time to give me your enthusiastic answers! !