import type { Theme } from "@mui/material/styles";
/**
 * Overlay stacking for elevated surfaces that sit above MUI's default modal layer.
 *
 * Baseline (MUI defaults): drawer 1200, modal 1300, snackbar 1400, tooltip 1500.
 * FormChat FAB uses modal + 1 so it stays above fullscreen chat shells.
 *
 * Use these helpers instead of raw `theme.zIndex.modal + N` so drawers, FABs,
 * and nested menus stay consistent across current and future surfaces.
 */
export declare const overlayZIndex: {
    /** Floating actions that must sit above modal shells (e.g. FormChat FAB). */
    readonly floatingAction: (theme: Theme) => number;
    /** Drawers that must sit above floating actions (e.g. FilterDrawer). */
    readonly elevatedDrawer: (theme: Theme) => number;
    /**
     * Portaled menus/selects/popovers opened from inside an elevated drawer.
     * Must be above elevatedDrawer or options render behind the sheet.
     */
    readonly nestedMenu: (theme: Theme) => number;
};