当悬停在圆圈内(黄色)外边框(高度和宽度)需要从中心和圆圈在同一位置增加(动画)吗?

Question

当悬停在圆圈内(黄色(外边框(高度和宽度(时，需要从中心增加(动画(，在边框内中心位置增加圆圈(黄色(

{
background-color: yellow;
border-radius: 50%;
border: 1px solid grey;
padding: 10px;
}
.circle {
position: absolute;
border: 5px solid #000;
border-radius: 50%;
width: 40px;
height: 40px;
transition: width 0.5s, height 0.5s;
}
.circle:hover {
width: 60px;
height: 60px;
}

<div class="circle">
<span><a><i class="icon_social fa fa-facebook-square"></i></a></span>
</div>

Answer 1

你可以写css，即

html {
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
box-sizing: border-box;
}
*, *:before, *:after {
-moz-box-sizing: inherit;
-webkit-box-sizing: inherit;
box-sizing: inherit;
}
.circle {
border-radius: 50%;
height: 40px;
margin-top: 20px;
position: relative;
transition: all 0.5s ease 0s;
width: 40px;
}
.circle::before {
border: 4px solid #000;
border-radius: 50%;
bottom: 0;  
content: "";
height: 100%;
left: 0;
margin: auto;
position: absolute;
right: 0;
top: 0;
-webkit-transition: all 0.5s ease 0s;
transition: all 0.5s ease 0s;
width: 100%;
}
.circle:hover::before {
-webkit-transform: scale(1.2);
transform: scale(1.2);
}
.circle span {
display: block;
height: 100%;
text-align: center;
vertical-align: middle;
width: 100%;
}
.circle a {
left: 50%;
margin: auto;
position: absolute;
text-align: center;
top: 50%;
transform: translate(-50%, -50%);
}
i {
background-color: yellow;
border: 1px solid grey;
border-radius: 50%;  
display: block;
padding: 10px;
text-align: center;
vertical-align: middle;
}

<div class="circle">
<span><a><i class="icon_social fa fa-facebook-square"></i></a></span>
</div>

Answer 2

它可能会帮助你..！

* {box-sizing: border-box;}
.holder {position: relative; display: inline-block; padding: 10px; border-radius: 50%; margin: 100px;}
.circle {position: absolute; top: 0px; left: 0px; border: solid 5px #000; width: 100%; height: 100%; border-radius: 50%; transition: all 0.3s ease;}
i {background: yellow; padding: 10px; border-radius: 50%;}
.circle:hover {transform: scale(1.2);}

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/>
<div class="holder">
	<i class="fa fa-facebook-square"></i>
	<div class="circle"></div>
</div>