@-moz-document regexp("^.*\.pdf(?:[?#].*)?$") {
    #viewerContainer > #viewer > .page > .canvasWrapper > canvas {
        filter: invert(100%);
    }

    /* Dark background behind PDF pages */
    #outerContainer,
    #mainContainer,
    #viewerContainer,
    #sidebarContainer,
    #sidebarContent,
    #thumbnailView,
    #outlineView,
    #attachmentsView,
    #layersView {
        background-color: #292D32 !important;
    }

    /* Dark toolbar */
    #toolbarContainer,
    .toolbar,
    #toolbarSidebar {
        background-color: #292D32 !important;
        color: #ccc !important;
    }

    .toolbarButton > svg path {
        fill: #ffffff !important;
    }

    /* Make toolbar icons white */
    .toolbarButton > svg,
    .toolbarButton::before,
    .toolbarButton::after {
        filter: invert(100%) brightness(200%) !important;
    }

    /* Toolbar buttons */
    .toolbarButton {
        background-color: transparent !important;
        color: #ccc !important;
    }

    /* Dropdowns and inputs */
    .toolbarField,
    select {
        background-color: #2c2c2c !important;
        color: #ccc !important;
        border: 1px solid #555 !important;
    }

    /* Dialogs (e.g., password prompt) */
    .dialog,
    .dialog .mainContainer {
        background-color: #292D32 !important;
        color: #ccc !important;
    }

    /* Optional: Adjust loading bar (hidden usually) */
    #loadingBar {
        background-color: #333 !important;
    }

    .toolbarLabel,
    #numPages,
    #pageNumber {
        color: #ccc !important;
    }

    /* Darken popup menus and drawers */
    .doorHangerRight,
    .menu,
    .editorParamsToolbar,
    .menuContainer,
    .dropdownToolbarButton select {
        background-color: #292D32 !important;
        color: #ccc !important;
        border: 1px solid #555 !important;
    }

    /* Fix labels and inputs inside menus */
    .editorParamsLabel,
    .dropdown button,
    #scaleSelect option {
        color: #ccc !important;
    }

    /* Better dark hover for dropdown buttons */
    .dropdown button:hover {
        background-color: #333 !important;
    }
}