// 设置 input placeholder 颜色
.placeholder(@size: 15px,@color: #ccc,@lineheight: normal) {
  &:-moz-placeholder{
    font-size: @size;
    color: @color;
    font-weight: normal;
  } // Firefox 4-18
  &::-moz-placeholder{
    font-size: @size;
    color: @color;   // Firefox 19+
    opacity: 1;
    font-weight: normal;
  }
  &:-ms-input-placeholder{
    font-size: @size;
    color: @color;
    font-weight: normal;
  } // Internet Explorer 10+
  &::-webkit-input-placeholder{
    font-size: @size;
    color: @color;
    font-weight: normal;
    line-height: @lineheight;
  } // Safari and Chrome
}
// 设置 input 通用样式
.input(){
  border: 0;
  border-radius: 0;
  outline: 0;
  appearance: none;
  background-color: transparent;
}