*{
  margin:0;
  padding:0;
}
ul li{
  list-style: none;
}
a{
  text-decoration: none;
}
/* 定义 */
.flex-def {
    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+ */
  }
  
  /* 主轴居中 */
  .flex-zCenter {
    -webkit-box-pack: center;
    -moz-justify-content: center;
    -webkit-justify-content: center;
    justify-content: center;
  }
  
  /* 主轴两端对齐 */
  .flex-zBetween {
    -webkit-box-pack: justify;
    -moz-justify-content: space-between;
    -webkit-justify-content: space-between;
    justify-content: space-between;
  }
   /* 主轴两端对齐 */
   .flex-zAround {
    -webkit-box-pack: justify;
    -moz-justify-content: space-around;
    -webkit-justify-content: space-around;
    justify-content: space-around;
  }
  
  /* 主轴end对齐 */
  .flex-zEnd {
    -webkit-box-pack: end;
    -moz-justify-content: flex-end;
    -webkit-justify-content: flex-end;
    justify-content: flex-end;
  }
  
  /* 主轴start对齐 */
  .flex-zStart {
    -webkit-box-pack: start;
    -moz-justify-content: start;
    -webkit-justify-content: start;
    justify-content: start;
  }
  
  /* 侧轴居中 */
  .flex-cCenter {
    -webkit-box-align: center;
    -moz-align-items: center;
    -webkit-align-items: center;
    align-items: center;
  }
  
  /* 侧轴start对齐 */
  .flex-cStart {
    -webkit-box-align: start;
    -moz-align-items: start;
    -webkit-align-items: start;
    align-items: start;
  }
  
  /* 侧轴底部对齐 */
  .flex-cEnd {
    -webkit-box-align: end;
    -moz-align-items: flex-end;
    -webkit-align-items: flex-end;
    align-items: flex-end;
  }
  
  /* 侧轴文本基线对齐 */
  .flex-cBaseline {
    -webkit-box-align: baseline;
    -moz-align-items: baseline;
    -webkit-align-items: baseline;
    align-items: baseline;
  }
  
  /* 侧轴上下对齐并铺满 */
  .flex-cStretch {
    -webkit-box-align: stretch;
    -moz-align-items: stretch;
    -webkit-align-items: stretch;
    align-items: stretch;
  }
  
  /* 主轴从上到下 */
  .flex-zTopBottom {
    -webkit-box-direction: normal;
    -webkit-box-orient: vertical;
    -moz-flex-direction: column;
    -webkit-flex-direction: column;
    flex-direction: column;
  }
  
  /* 主轴从下到上 */
  .flex-zBottomTop {
    -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;
  }
  
  /* 主轴从左到右 */
  .flex-zLeftRight {
    -webkit-box-direction: normal;
    -webkit-box-orient: horizontal;
    -moz-flex-direction: row;
    -webkit-flex-direction: row;
    flex-direction: row;
  }
  
  /* 主轴从右到左 */
  .flex-zRightLeft {
    -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;
  }
  
  /* 是否允许子元素伸缩 */
  .flex-item {
    -webkit-box-flex: 1.0;
    -moz-flex-grow: 1;
    -webkit-flex-grow: 1;
    flex-grow: 1;
  }
  /* 子元素的显示次序 */
  .flex-order{
    -webkit-box-ordinal-group: 1;
    -moz-order: 1;
    -webkit-order: 1;
    order: 1;
  }