iview/styles/components/button.less

@btn-prefix-cls: ~"@{css-prefix}btn";

.@{btn-prefix-cls} {
    .btn;
    .btn-default;

    &-primary {
        .btn-primary;

        .@{btn-prefix-cls}-group &:not(:first-child):not(:last-child) {
            border-right-color: @btn-group-border;
            border-left-color: @btn-group-border;
        }

        .@{btn-prefix-cls}-group &:first-child {
            &:not(:last-child) {
                border-right-color: @btn-group-border;
                &[disabled] {
                    border-right-color: @btn-default-border;
                }
            }
        }

        .@{btn-prefix-cls}-group &:last-child:not(:first-child),
        .@{btn-prefix-cls}-group & + .@{btn-prefix-cls} {
            border-left-color: @btn-group-border;
            &[disabled] {
                border-left-color: @btn-default-border;
            }
        }
    }

    &-ghost {
        .btn-ghost;
    }

    //&-dashed {
    //    .btn-dashed;
    //}

    &-circle,
    &-circle-outline {
        .btn-circle(@btn-prefix-cls);
    }

    &:before {
        position: absolute;
        top: -1px;
        left: -1px;
        bottom: -1px;
        right: -1px;
        background: #fff;
        opacity: 0.35;
        content: '';
        border-radius: inherit;
        z-index: 1;
        .transition(opacity @transition-time);
        pointer-events: none;
        display: none;
    }

    &&-loading {
        pointer-events: none;
        position: relative;

        &:before {
            display: block;
        }
    }

    &-group {
        .btn-group(@btn-prefix-cls);
    }
}