border-color默认就是color:当没有指定border-color的时候,会使用color的颜色
类型的还有 box-shadow,text-shadow,outline等
实际用途:hover

border-color
1、在没有指定border-color时,默认使用color作为边框色
box-shadow、text-shadow、outline均有此特性
2、案例


只需一个color的hover变化,就可以一起变色;且transition过渡也只要一个color属性
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.add {
display: inline-block;
width: 120px;
height: 120px;
border: 1px solid;
color: #ccc;
position: relative;
transition: color 0.5s;
}
.add:before {
content: "";
display: block;
width: 80px;
border-top: 10px solid;
position: absolute;
left:20px;
top: 55px;
}
.add:after {
content: "";
display: block;
height: 80px;
border-left: 10px solid;
position: absolute;
left: 55px;
top: 20px;
}
.add:hover {
color: #234BD5;
}
</style>
</head>
<body>
<a href="" class="add"></a>
</body>
</html>
border-color的默认颜色就是color
1.添加了过渡
2.利用了calc函数居中
3.声明父div,设置border的时候不声明颜色,只声明color
4.before,after不声明color,继承父元素div的color
<!DOCTYPE html>
<html>
<head><meta charset="UTF-8">
<title>Document</title>
<style>
div {
border: 1px solid;
color: blue;
width: 150px;
height: 150px;
position: relative;
transition: 1s color;
}
/* 横着放 */
div::before {
content: "";
width: 60px;
height: 20px;
border-bottom: 20px solid;
display:inline-block;
box-sizing: border-box;
position: absolute;
left: calc(50% - 30px);
top: calc(50% - 10px);
}
/* 竖着放 */
div::after {
content: "";
height: 60px;
width: 20px;
border-left: 20px solid;
display:inline-block;
box-sizing: border-box;
position: absolute;
z-index: 1;
left: calc(50% - 10px);
top: calc(50% - 30px);
}
div:hover {
color: red;
}
</style>
</head>
<body>
<div></div>
</body>
</html>
border-color默认颜色就是color,类似的还有box-shadow,text-shadow
border-color默认值
++++++++++++++
十字和框都是border画的
---------------
+++++++++++
---------------------
border的颜色随着color颜色变化,可以改变color值让边框变色
当没有制定border-color的时候,会使用color作为边框色
这个ppt变色的效果怎么实现哒
利用color变色
不利用border-color的变色方法
border-color没有指定颜色的时候会呈现默认的颜色如:border:1px solid;
<!DOCTYPE html>
<html>
<head></head>
<style>
.add{
display: block;
width: 100px;
height: 100px;
position: relative;
color: #ccc;
transition: color .25s;
border: 1px solid;
}
.add:before {
content: "";
width: 80px;
position: absolute;
left: 10px;
top: 45px;
border-top:10px solid;
}
.add:after {
content: "";
height: 80px;
position: absolute;;
left: 45px;
top: 10px;
border-left: 10px solid;
}
.add:hover {
color: #067;
}
</style>
<body>
<div >
</div>
<p></p>
<a class="add" href="javascript:"></a>
</body>
</html>
better way