.header (@height, @bg, @left) {
    height: @height;
    line-height: @height;
    text-align: center;
    position: relative;
    background-color: @bg;
    color: #fff;
    .px2px(font-size, 18px);

    .back {
        position: absolute;
        left: @left;
        width: 20px;

        &:before {
            content: "";
            display: inline-block;
            width: 10px;
            height: 10px;
            left: 0;
            border-top: 2px solid #fff;
            border-left: 2px solid #fff;
            -webkit-transform: rotate(-45deg);
            -moz-transform: rotate(-45deg);
            transform: rotate(-45deg);
        }
    }
}


.icon () {
    /* search icon */
    .s-icon, .r-icon {
        height: 100%;
        width: 20px;
        top: 0;
        position: absolute;
        margin-left: 0.12rem;
    }
    .r-icon {
        padding-right: .12rem;
        margin-left: 0;
        width: 30px;
    }
    .s-icon:after, .r-icon:after {
        content: "";
        display: block;
        background: @icon no-repeat;
        background-size: 100px 25px;
        background-position: -6px -2px;
        width: 20px;
        height: 20px;
        top: 50%;
        left: 0;
        position: relative;
        -webkit-transform: translateY(-50%);
           -moz-transform: translateY(-50%);
                 tansform: translateY(-50%);
    }
    /* remove icon */
    .r-icon:after {
        background-position: -30px -3px;
        margin-left: 10px;
    }
}

.search () {
    .search-bar {
        .flex-display(flex);
        margin: .2rem;
        height: .58rem;
        line-height: .58rem;
        .px2px(font-size, 14px);

        .content {
            position: relative;
            display: block;
            border: 1px solid #ddd;
            background-color: #fff;
            height: 100%;
            -webkit-box-sizing: border-box;
                    box-sizing: border-box;

            .flex(2);

            .s-icon {
                left: 0;
            }
            .r-icon {
                display: none;
                right: 0;
            }

            .search {
                border: 0;
                height: 100%;
                width: 100%;
                padding: 0 0 0 .6rem;
                color: #262626;
                outline: none;
                vertical-align: top;
                -webkit-appearance: none;
                -webkit-box-sizing: border-box;
                        box-sizing: border-box;
            }
        }

        .btn-search {
            display: none;
            width: .64rem;
            color: #777;
            text-align: right;
        }
    }

    .focus-bar {
        .content {
            .s-icon {
                display: none;
            }

            .search {
                padding-left: .12rem;
            }
        }
        .btn-search {
            display: block;
        }
    }
}