use gpui::{    div, AnyElement, Bounds, Div, DivFrameState, Element, ElementId, GlobalElementId, Hitbox,    IntoElement, LayoutId, ParentElement, Pixels, StyleRefinement, Styled, WindowContext,}; /// An element that sets a particular rem size for its children.pub struct WithRemSize {    div: Div,    rem_size: Pixels,} impl WithRemSize {    /// Create a new [WithRemSize] element, which sets a    /// particular rem size for its children.    pub fn new(rem_size: impl Into<Pixels>) -> Self {        Self {            div: div(),            rem_size: rem_size.into(),        }    }} impl Styled for WithRemSize {    fn style(&mut self) -> &mut StyleRefinement {        self.div.style()    }} impl ParentElement for WithRemSize {    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {        self.div.extend(elements)    }} impl Element for WithRemSize {    type RequestLayoutState = DivFrameState;    type PrepaintState = Option<Hitbox>;     fn id(&self) -> Option<ElementId> {        self.div.id()    }     fn request_layout(        &mut self,        id: Option<&GlobalElementId>,        cx: &mut WindowContext,    ) -> (LayoutId, Self::RequestLayoutState) {        cx.with_rem_size(Some(self.rem_size), |cx| self.div.request_layout(id, cx))    }     fn prepaint(        &mut self,        id: Option<&GlobalElementId>,        bounds: Bounds<Pixels>,        request_layout: &mut Self::RequestLayoutState,        cx: &mut WindowContext,    ) -> Self::PrepaintState {        cx.with_rem_size(Some(self.rem_size), |cx| {            self.div.prepaint(id, bounds, request_layout, cx)        })    }     fn paint(        &mut self,        id: Option<&GlobalElementId>,        bounds: Bounds<Pixels>,        request_layout: &mut Self::RequestLayoutState,        prepaint: &mut Self::PrepaintState,        cx: &mut WindowContext,    ) {        cx.with_rem_size(Some(self.rem_size), |cx| {            self.div.paint(id, bounds, request_layout, prepaint, cx)        })    }} impl IntoElement for WithRemSize {    type Element = Self;     fn into_element(self) -> Self::Element {        self    }}