// 设置<a>链接的颜色及样式
// @color 如果不是颜色，则表示其他参数向前顺延
// @decoration 定义链接hover时，是否显示下划线
._link-color(@color, @active_color, @decoration: underline, @active_class: active) {
    color: @color;
    text-decoration: none;

    .hover({
        color: @active_color;

        & when (@decoration = none) {
            text-decoration: none;
        }

        & when not (@decoration = none) {
            text-decoration: underline;
        }

    }, @active_class);
}

.link-color(@color, @decoration: underline, @active_class: active) when (iscolor(@color)) {
    ._link-color(@color, @color, @decoration, @active_class);
}
.link-color(@color, @decoration: underline, @active_class: active) when (length(@color) > 1) {
    ._link-color(extract(@color, 1), extract(@color, 2), @decoration, @active_class);
}
.link-color(@color, @decoration: none, @active_class: active) when (length(@color) = 1) and not (iscolor(@color)) {
    ._link-color(inherit, inherit, @decoration, @active_class);
}