/*伸缩盒子模型*/
.box {
	display: -webkit-box;
	/* 老版本语法: Safari, iOS, Android browser, older WebKit browsers. */
	display: -moz-box;
	/* 老版本语法: Firefox (buggy) */
	display: -ms-flexbox;
	/* 混合版本语法: IE 10 */
	display: -webkit-flex;
	/* 新版本语法: Chrome 21+ */
	display: flex;
	/* 新版本语法: Opera 12.1, Firefox 22+ */
	-webkit-flex-wrap: nowrap;
	-ms-flex-wrap: nowrap;
	flex-wrap: nowrap;
}

/*从左至右*/

.box-lr {
	-webkit-box-direction: normal;
	-webkit-box-orient: horizontal;
	-moz-flex-direction: row;
	-webkit-flex-direction: row;
	flex-direction: row;
}


/*从右至左*/

.box-rl {
	-webkit-box-pack: end;
	-webkit-box-direction: reverse;
	-webkit-box-orient: horizontal;
	-moz-flex-direction: row-reverse;
	-webkit-flex-direction: row-reverse;
	flex-direction: row-reverse;
}


/*从上至下*/

.box-tb {
	-webkit-box-direction: normal;
	-webkit-box-orient: vertical;
	-moz-flex-direction: column;
	-webkit-flex-direction: column;
	flex-direction: column;
}


/*从下至上*/

.box-bt {
	-webkit-box-pack: end;
	-webkit-box-direction: reverse;
	-webkit-box-orient: vertical;
	-moz-flex-direction: column-reverse;
	-webkit-flex-direction: column-reverse;
	flex-direction: column-reverse;
}


/*主轴居中*/

.box-pack-center {
	-webkit-box-pack: center;
	-moz-justify-content: center;
	-webkit-justify-content: center;
	justify-content: center;
}

.middle {
	display: flex;
	justify-content: space-between;
	/*justify-content: space-evenly;*/
}

.middle::before,
.middle::after {
	content: '';
	display: block;
}

/*主轴居左*/

.box-pack-start {
	-webkit-box-pack: start;
	-moz-justify-content: flex-start;
	-webkit-justify-content: flex-start;
	justify-content: flex-start;
}


/*主轴居右*/

.box-pack-end {
	-webkit-box-pack: end;
	-moz-justify-content: flex-end;
	-webkit-justify-content: flex-end;
	justify-content: flex-end;
}


/*主轴左右不留白*/

.box-pack-between {
	-webkit-box-pack: justify;
	-moz-justify-content: space-between;
	-webkit-justify-content: space-between;
	justify-content: space-between;
}


/*主轴左右留白*/

.box-pack-around {
	-moz-justify-content: space-around;
	-webkit-justify-content: space-around;
	justify-content: space-around;
}

/*自动间隔，每个元素的间隔相等*/

.box-middle {
	-moz-justify-content: space-evenly;
	-webkit-justify-content: space-evenly;
	justify-content: space-evenly;
}

/*交叉轴居中对齐*/

.box-align-center {
	-webkit-box-align: center;
	-moz-align-items: center;
	-webkit-align-items: center;
	align-items: center;
}


/*交叉轴居左对齐*/

.box-align-start {
	-webkit-box-align: start;
	-moz-align-items: start;
	-webkit-align-items: flex-start;
	align-items: flex-start;
}


/*交叉轴居右对齐*/

.box-align-end {
	-webkit-box-align: end;
	-moz-align-items: end;
	-webkit-align-items: flex-end;
	align-items: flex-end;
}


/**单个指定的子元素自定义对齐方式，可以不同于其他子元素对齐方式**/


/**指定子元素居中对齐**/

.self-align-center {
	align-self: center;
	-webkit-align-self: center;
	margin: 0 auto;
}


/**指定子元素顶部对齐**/

.self-align-start {
	align-self: flex-start;
	-webkit-align-self: flex-start;
}


/**指定子元素底部对齐**/

.self-align-end {
	align-self: flex-end;
	-webkit-align-self: flex-end;
}


/**指定子元素拉伸**/

.self-align-stretch {
	align-self: stretch;
	-webkit-align-self: stretch;
}


/**子元素换行**/

.box-wrap {
	-webkit-flex-wrap: wrap;
	-ms-flex-wrap: wrap;
	flex-wrap: wrap;
}


/**子元素不换行**/

.box-nowrap {
	-webkit-flex-wrap: nowrap;
	-ms-flex-wrap: nowrap;
	flex-wrap: nowrap;
}


/*允许子元素伸展（1倍）*/

.flex {
	-moz-flex-grow: 1;
	-webkit-flex-grow: 1;
	flex-grow: 1;
	/*如果值是2 那么当前元素就是其他元素宽的2倍了*/
}

/* flex:1 是 flex-grow、flex-shrink、flex-basis的缩写。故其取值可以考虑以下情况：
        flex-grow:0表示不会拉伸 flex-shrink:1表示 可以缩小
        flex 的默认值是以上三个属性值的组合。假设以上三个属性同样取默认值，则 flex 的默认值是 0 1 auto*/

/*允许子元素收缩(1倍)*/

.shrink {
	-moz-flex-shrink: 1;
	-webkit-flex-shrink: 1;
	flex-shrink: 1;
}


/**水平居中*/

.box-center-center {
	display: -webkit-box;
	-webkit-box-align: center;
	-webkit-box-pack: center;
	display: -moz-box;
	-moz-box-align: center;
	-moz-box-pack: center;
	text-align: center;
}

/**垂直居中*/

.vertical-container {
  display: -webkit-flex;
  display:         flex;
  -webkit-align-items: center;
          align-items: center;
  -webkit-justify-content: center;
          justify-content: center;
}