/****添加计算宽度的--运算符直接需要space****/
/****** common color(常用颜色,可用于普遍场景) *****/
/**** custom color(自定义颜色,用于特定场景) ****/
.bi-segment > .center-element {
  overflow: hidden;
  overflow-x: hidden;
  overflow-y: hidden;
  background: #ffffff;
  border-right: 1px solid #d4dadd;
  border-top: 1px solid #d4dadd;
  border-bottom: 1px solid #d4dadd;
}
.bi-segment > .first-element {
  border-left: 1px solid #d4dadd;
  -webkit-border-radius: 6px 0px 0px 6px;
  -moz-border-radius: 6px 0px 0px 6px;
  border-radius: 6px 0px 0px 6px;
}
.bi-segment > .last-element {
  -webkit-border-radius: 0px 6px 6px 0px;
  -moz-border-radius: 0px 6px 6px 0px;
  border-radius: 0px 6px 6px 0px;
}