introduce typography system and motion module

crates/ui/src/root.rs

@@ -11,7 +11,7 @@ use gpui::{
 use gpui_base::TextSelectionLayer;
 use theme::{
     ActiveTheme, CLIENT_SIDE_DECORATION_BORDER, CLIENT_SIDE_DECORATION_ROUNDING,
-    CLIENT_SIDE_DECORATION_SHADOW, surface_shadows,
+    CLIENT_SIDE_DECORATION_SHADOW, base_text_size, surface_shadows,
 };
 
 use crate::dialog::Dialog;
@@ -234,8 +234,8 @@ impl Root {
 
 impl Render for Root {
     fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
-        let rem_size = cx.theme().font_size;
-        let font_family = cx.theme().font_family.clone();
+        let rem_size = px(base_text_size());
+        let font_family = cx.theme().font_sans.clone();
         let decorations = window.window_decorations();
 
         // Set the base font size