.button-size(@padding;
@font-size;
@border-radius) {
    padding: @padding;
    font-size: @font-size;
    border-radius: @border-radius;
}

.button-color(@color;
@background;
@border) {
    color: @color;
    background-color: @background;
    border-color: @border; // a inside Button which only work in Chrome
    // http://stackoverflow.com/a/17253457
    > a:only-child {
        color: currentColor;
        &:after {
            content: "";
            position: absolute;
            top: 0;
            left: 0;
            bottom: 0;
            right: 0;
            background: transparent;
        }
    }
}

.button-variant(@color;
@background;
@border) {
    .button-color(@color; @background; @border);
    &:hover //&:focus
 {
        .button-color(
            tint(@color, 20%) ; tint(@background, 20%) ; tint(@border, 20%)
        );
    }
    &:active,
    &.active {
        .button-color(
            shade(@color, 5%) ; shade(@background, 5%) ; shade(@background, 5%)
        );
    }
    &.disabled,
    &[disabled],
    fieldset[disabled] & {
        &,
        &:hover,
        &:focus,
        &:active,
        &.active {
            .button-color(
                @btn-disable-color; @btn-disable-bg; @btn-disable-border
            );
        }
    }
}

.button-group-base(@btnClassName) {
    position: relative;
    display: inline-block;
    vertical-align: middle;
    > .@{btnClassName} {
        position: relative;
        float: left;
        &:hover, //&:focus,
    &:active,
    &.active {
            z-index: 2;
        }
    }
    & .@{btnClassName}-icon-only .ivu-icon {
        font-size: 13px;
        position: relative; // top: 1px;
    }
    &-large .@{btnClassName}-icon-only .ivu-icon {
        font-size: 15px; //top: 2px;
    }
    &-small .@{btnClassName}-icon-only .ivu-icon {
        font-size: 12px; //top: 0;
    }
    &-circle .@{btnClassName} {
        border-radius: @btn-circle-size;
    } // size
    &-large&-circle .@{btnClassName} {
        border-radius: @btn-circle-size-large;
    }
    &-large {
        & > .@{btnClassName} {
            .button-size(
                @btn-padding-large; @btn-font-size-large; @btn-border-radius
            );
        }
    }
    &-small&-circle .@{btnClassName} {
        border-radius: @btn-circle-size-small;
    }
    &-small {
        & > .@{btnClassName} {
            .button-size(
                @btn-padding-small; @btn-font-size-small;
                    @btn-border-radius-small
            );
            > .@{css-prefix-iconfont} {
                font-size: @btn-font-size;
            }
        }
    }
}

.button-group-vertical-base(@btnClassName) {
    display: inline-block;
    vertical-align: middle;
    > .@{btnClassName} {
        display: block;
        width: 100%;
        max-width: 100%;
        float: none;
    }
}

.btn() {
    display: inline-block;
    margin-bottom: 0;
    font-weight: @btn-font-weight;
    text-align: center;
    vertical-align: middle;
    touch-action: manipulation;
    cursor: pointer;
    background-image: none;
    border: 1px solid transparent;
    white-space: nowrap;
    line-height: @line-height-base;
    user-select: none;
    .button-size(
        @btn-padding-base; @btn-font-size; @btn-border-radius
    ); //transform: translate3d(0, 0, 0);
    //transition: all @transition-time linear;
    transition: color @transition-time linear,
        background-color @transition-time linear, border @transition-time linear,
        box-shadow @transition-time linear;
    > .@{css-prefix-iconfont} {
        line-height: @line-height-base;
        vertical-align: middle;
    }
    &-icon-only&-circle > .@{css-prefix-iconfont} {
        vertical-align: baseline;
    }
    > span {
        vertical-align: middle;
    }
    &,
    &:active,
    &:focus {
        outline: 0;
    }
    &:not([disabled]):hover {
        text-decoration: none;
    }
    &:not([disabled]):active {
        outline: 0; // transition: none;  // 如果不注释此行，那么active会和focus同时触发，此时focus的开始动画transition会无效
    }
    &.disabled,
    &[disabled] {
        cursor: @cursor-disabled;
        > * {
            pointer-events: none;
        }
    }
    &-large {
        .button-size(
            @btn-padding-large; @btn-font-size-large; @btn-border-radius
        );
    }
    &-small {
        .button-size(
            @btn-padding-small; @btn-font-size-small; @btn-border-radius-small
        );
    }
    &-icon-only {
        .button-size(
            @btn-padding-base-icon; @btn-font-size; @btn-border-radius
        );
    }
    &-icon-only&-small {
        .button-size(
            @btn-padding-small-icon; @btn-font-size; @btn-border-radius-small
        );
    }
    &-icon-only&-large {
        .button-size(
            @btn-padding-large-icon; @btn-font-size-large; @btn-border-radius
        );
    }
}

// Default
.btn-default() {
    .button-variant(white; @btn-default-bg; @btn-default-border);
    &:hover //&:focus
 {
        .button-color(white; @btn-default-hover-bg; @btn-default-border);
    }
    &:active,
    &.active {
        .button-color(white; @btn-default-hover-bg; @btn-default-border);
    }
    .active-btn-color(@primary-color);
}

// Primary
.btn-primary() {
    .button-variant(@btn-primary-color; @btn-primary-bg; @primary-color);
    &:hover, //&:focus,
  &:active,
  &.active {
        color: @btn-primary-color;
    }
    .active-btn-color(@primary-color);
}

// Ghost
.btn-ghost() {
    .button-variant(@btn-ghost-color, @btn-ghost-bg, @btn-ghost-border);
    &:hover //&:focus
 {
        .button-color(
            tint(@primary-color, 20%) ; @btn-ghost-hover-bg;
                tint(@primary-color, 20%)
        );
    }
    &:active,
    &.active {
        .button-color(
            shade(@primary-color, 5%) ; @btn-ghost-bg; shade(@primary-color, 5%)
        );
    }
    .active-btn-color(@primary-color);
}

// Dashed
.btn-dashed() {
    .button-variant(@btn-ghost-color, @btn-ghost-bg, @btn-ghost-border);
    border-style: dashed;
    &:hover //&:focus
 {
        .button-color(
            tint(@primary-color, 20%) ; @btn-ghost-bg; tint(@primary-color, 20%)
        );
    }
    &:active,
    &.active {
        .button-color(
            shade(@primary-color, 5%) ; @btn-ghost-bg; shade(@primary-color, 5%)
        );
    }
    .active-btn-color(@primary-color);
}

// Text
.btn-text() {
    .button-variant(
        @btn-ghost-color,
        @btn-ghost-bg,
        transparent
    ); // for disabled
    &.disabled,
    &[disabled],
    fieldset[disabled] & {
        &,
        &:hover,
        &:focus,
        &:active,
        &.active {
            .button-color(@btn-disable-color; @btn-ghost-bg; transparent);
        }
    }
    &:hover //&:focus
 {
        .button-color(tint(@primary-color, 20%) ; @btn-ghost-bg; transparent);
    }
    &:active,
    &.active {
        .button-color(shade(@primary-color, 5%) ; @btn-ghost-bg; transparent);
    }
    .active-btn-color(@primary-color);
}

// Color
// for tabindex
.active-btn-color(@color) {
    &:focus {
        box-shadow: 0 0 0 2px fade(@color, 20%);
    }
}

.btn-color(@color) {
    .button-variant(@btn-primary-color; @color; @color);
    &:hover, //&:focus,
  &:active,
  &.active {
        color: @btn-primary-color;
    }
    .active-btn-color(@color);
}

// Circle for Icon
.btn-circle(@btnClassName: ivu-btn) {
    border-radius: @btn-circle-size;
    &.@{btnClassName}-large {
        border-radius: @btn-circle-size-large;
    }
    &.@{btnClassName}-size {
        border-radius: @btn-circle-size-small;
    }
    &.@{btnClassName}-icon-only {
        .square(@btn-circle-size);
        .button-size(0; @font-size-base + 2; 50%);
        &.@{btnClassName}-large {
            .square(@btn-circle-size-large);
            .button-size(0; @btn-font-size-large + 2; 50%);
        }
        &.@{btnClassName}-small {
            .square(@btn-circle-size-small);
            .button-size(0; @font-size-base; 50%);
        }
    }
}

// Group
.btn-group(@btnClassName: ivu-btn) {
    .button-group-base(@btnClassName);
    .@{btnClassName} + .@{btnClassName},
    .@{btnClassName} + &,
    & + .@{btnClassName},
    & + & {
        margin-left: -1px;
    }
    .@{btnClassName}:not(:first-child):not(:last-child) {
        border-radius: 0;
    }
    &:not(&-vertical) > .@{btnClassName}:first-child {
        margin-left: 0;
        &:not(:last-child) {
            border-bottom-right-radius: 0;
            border-top-right-radius: 0;
        }
    }
    &:not(&-vertical) > .@{btnClassName}:last-child:not(:first-child) {
        border-bottom-left-radius: 0;
        border-top-left-radius: 0;
    }
    & > & {
        float: left;
    }
    & > &:not(:first-child):not(:last-child) > .@{btnClassName} {
        border-radius: 0;
    }
    &:not(&-vertical) > &:first-child:not(:last-child) {
        > .@{btnClassName}:last-child {
            border-bottom-right-radius: 0;
            border-top-right-radius: 0;
            padding-right: 8px;
        }
    }
    &:not(&-vertical)
        > &:last-child:not(:first-child)
        > .@{btnClassName}:first-child {
        border-bottom-left-radius: 0;
        border-top-left-radius: 0;
        padding-left: 8px;
    }
}

.btn-group-vertical(@btnClassName: ivu-btn) {
    .button-group-vertical-base(@btnClassName);
    .@{btnClassName} + .@{btnClassName},
    .@{btnClassName} + &,
    & + .@{btnClassName},
    & + & {
        margin-top: -1px;
        margin-left: 0px;
    }
    > .@{btnClassName}:first-child {
        margin-top: 0;
        &:not(:last-child) {
            border-bottom-left-radius: 0;
            border-bottom-right-radius: 0;
        }
    }
    > .@{btnClassName}:last-child:not(:first-child) {
        border-top-left-radius: 0;
        border-top-right-radius: 0;
    }
    & > &:first-child:not(:last-child) {
        > .@{btnClassName}:last-child {
            border-bottom-left-radius: 0;
            border-bottom-right-radius: 0;
            padding-bottom: 8px;
        }
    }
    & > &:last-child:not(:first-child) > .@{btnClassName}:first-child {
        border-bottom-right-radius: 0;
        border-bottom-left-radius: 0;
        padding-top: 8px;
    }
}