.ydb-stack {
    $block: &;

    --ydb-stack-base-z-index: 100;
    --ydb-stack-offset-x: 50%;
    --ydb-stack-gap: 4px;
    --ydb-stack-padding: 5px;
    --ydb-stack-border-width: 1px;
    --ydb-stack-visible-donor-scale: 0.85;
    --ydb-stack-offset-y-base: 8px;
    --ydb-stack-offset-y: calc(
        var(--ydb-stack-offset-y-base) + var(--ydb-stack-item-height) *
            (1 - var(--ydb-stack-visible-donor-scale)) * 0.5
    );
    --ydb-stack-visible-donor-offset-x: calc(
        var(--ydb-stack-offset-x) - var(--ydb-stack-offset-x) * var(--ydb-stack-visible-donor-scale)
    );
    --ydb-stack-item-height: var(--progress-bar-full-height, var(--g-text-subheader-2-line-height));
    --ydb-stack-panel-inset: calc(var(--ydb-stack-padding) + var(--ydb-stack-border-width));
    --ydb-stack-background-collapsed-height: calc(
        var(--ydb-stack-item-height) + 2 * var(--ydb-stack-padding) + 2 *
            var(--ydb-stack-border-width) + var(--ydb-stack-offset-y)
    );
    --ydb-stack-background-expanded-height: calc(
        var(--ydb-stack-items-count) * var(--ydb-stack-item-height) +
            (var(--ydb-stack-items-count) - 1) * var(--ydb-stack-gap) + 2 *
            var(--ydb-stack-padding) + 2 * var(--ydb-stack-border-width)
    );

    position: relative;
    z-index: var(--ydb-stack-base-z-index);

    min-height: 100%;

    &_compact {
        --ydb-stack-item-height: var(--progress-bar-compact-height, 20px);
    }

    &__background {
        position: absolute;
        z-index: calc(var(--ydb-stack-base-z-index) - 1);
        top: calc(-1 * var(--ydb-stack-panel-inset));
        left: calc(-1 * var(--ydb-stack-panel-inset));

        visibility: hidden;

        box-sizing: border-box;
        width: calc(100% + 2 * var(--ydb-stack-panel-inset));
        height: var(--ydb-stack-background-collapsed-height);

        pointer-events: none;

        opacity: 0;
        border: var(--ydb-stack-border-width) solid var(--g-color-line-generic);
        border-radius: var(--g-border-radius-xl);
        background: var(--g-color-base-background);
        box-shadow: 0 4px 12px var(--g-color-sfx-shadow);

        transition:
            height 0.15s ease-out,
            opacity 0.15s ease-out,
            visibility 0s linear 0.15s,
            transform 0.15s ease-out;
    }

    &__item {
        transition:
            top 0.15s ease-out,
            opacity 0.15s ease-out,
            visibility 0s linear 0.15s,
            transform 0.15s ease-out;

        &_main {
            position: relative;
            z-index: calc(var(--ydb-stack-base-z-index) + 2);
        }

        &_donor {
            position: absolute;
            z-index: var(--ydb-stack-base-z-index);
            top: 0;
            left: 0;

            width: 100%;
            height: 100%;

            transform: translate(var(--ydb-stack-visible-donor-offset-x), var(--ydb-stack-offset-y))
                scale(var(--ydb-stack-visible-donor-scale));
            transform-origin: top left;
        }

        &_collapsed-hidden {
            visibility: hidden;

            pointer-events: none;

            opacity: 0;
        }
    }

    &:hover,
    &:focus-within,
    &_expanded {
        z-index: calc(var(--ydb-stack-base-z-index) + 10);

        #{$block}__background {
            visibility: visible;

            height: var(--ydb-stack-background-expanded-height);

            pointer-events: auto;

            opacity: 1;

            transition-delay: 0s;
        }

        #{$block}__item {
            position: absolute;
            top: calc(
                var(--ydb-stack-level) * (var(--ydb-stack-item-height) + var(--ydb-stack-gap))
            );
            left: 0;

            visibility: visible;

            width: 100%;
            height: 100%;

            pointer-events: auto;

            opacity: 1;

            transition-delay: 0s;
            transform: none;
        }
    }
}