css3

CSS中::after和:after的区别

::after表示法是在CSS3中引入的，::符号是指伪元素，:符号是指伪类。
          element:after        {style properties}              /*CSS2语法*/
          element::after       {style properties}              /*CSS3语法*/
用于向渲染的元素后添加内容。

box-sizing

div
{
box-sizing:border-box;
-moz-box-sizing:border-box; /* Firefox */
-webkit-box-sizing:border-box; /* Safari */
50%;
float:left;
}

具体参考：https://www.w3school.com.cn/cssref/pr_box-sizing.asp

(全) flex布局兼容性 兼容新老浏览器、移动端浏览器

/* 父元素-flex容器 */
.flex{
    display: flex;
    display: -moz-box; /* Firefox 17- */  
    display: -webkit-flex; /* Chrome 21+, Safari 6.1+, iOS Safari 7+, Opera 15/16 */  
    display: -moz-flex; /* Firefox 18+ */  
    display: -ms-flexbox; /* IE 10 */ 
}
/* 父元素-纵向排列（主轴） */
.flex-column{
    -webkit-box-orient: vertical;
    flex-direction: column;
    -webkit-flex-direction: column;
    -ms-flex-direction: column;
    -moz-flex-direction: column;
    -o-flex-direction: column;
}
/* 子元素-平均分栏 */
.flex1{
    -webkit-flex: 1; /* Chrome */
    -ms-flex: 1; /* IE 10 */
    flex: 1; /* NEW, Spec - Opera 12.1, Firefox 20+ */
    -webkit-box-flex: 1; /* OLD - iOS 6-, Safari 3.1-6 */
    -moz-box-flex: 1; /* OLD - Firefox 19- */
}
/* 父元素-横向换行 */
.flex-wrap{
    -webkit-flex-wrap: wrap;
    -moz-flex-wrap: wrap;
    -ms-flex-wrap: wrap;
    -o-flex-wrap: wrap;
    flex-wrap: wrap;
}
/* 父元素-竖直居中（主轴是横向才生效） */
.align-center{
    -webkit-box-align: center;
    -moz-align-items: center;
    -ms-align-items: center;
    -o-align-items: center;
    -webkit-align-items: center;
    align-items: center;
}
.align-start{
    -webkit-box-align: start;
    -moz-align-items: flex-start;
    -ms-align-items: flex-start;
    -o-align-items: flex-start;
    -webkit-align-items: flex-start;
    align-items: flex-start;
}
.align-end{
    -webkit-box-align: end;
    -moz-align-items: flex-end;
    -ms-align-items: flex-end;
    -o-align-items: flex-end;
    -webkit-align-items: flex-end;
    align-items: flex-end;
}
/* 父元素-水平居中（主轴是横向才生效） */
.justify-center{
    -webkit-box-pack: center;
    -ms-justify-content: center;
    -moz-justify-content: center;
    -o-justify-content: center;
    -webkit-justify-content: center;
    justify-content: center;
}
.justify-between{
    -webkit-box-pack: justify;
    -ms-justify-content: space-between;
    -moz-justify-content: space-between;
    -o-justify-content: space-between;
    -webkit-justify-content: space-between;
    -webkit-justify-content: space-between;
    justify-content: space-between;
}
.justify-around{
    -webkit-box-pack: justify;
    -ms-justify-content: space-around;
    -moz-justify-content: space-around;
    -o-justify-content: space-around;
    -webkit-justify-content: space-around;
    -webkit-justify-content: space-around;
    justify-content: space-around;
}
.justify-end{
    -webkit-box-pack: end;
    -ms-justify-content: flex-end;
    -moz-justify-content: flex-end;
    -o-justify-content: flex-end;
    -webkit-justify-content: flex-end;
    -webkit-justify-content: flex-end;
    justify-content: flex-end;
}