🐛(frontend) restore automatic lower-hand on speaking

Following the re-rendering optimization refactoring, the automatic
lower-hand feature broke: the way `isSpeaking` was read no longer
made sense once we limited how often components in the app
re-render.

Fix the detection so the raised hand is again lowered automatically
when the participant starts speaking, without relying on frequent
re-renders.

CHANGELOG.md

@@ -23,7 +23,6 @@ and this project adheres to
 - 🐛(backend) allow any printable ASCII characters in user sub field #1673
 - 🐛(frontend) keep the sending resolution picked while the camera is off #1667
 - 🐛(frontend) restore automatic lower-hand on speaking
-- 🐛(frontend) center Avatar initials with a font-aware cap-height ratio
 
 ## [1.30.0] - 2026-09-01
 

docker/dinum-frontend/dinum-styles.css

@@ -1,6 +1,5 @@
 :root {
     --fonts-sans: 'Marianne', ui-sans-serif, system-ui, sans-serif;
-    --avatar-cap-height: 0.7;
 }
 
 .Header-beforeLogo {

docs/theming.md

@@ -34,7 +34,6 @@ Let's say you want to change the font of our application to a custom font. You c
 
 :root {
   --fonts-sans: 'Roboto', ui-sans-serif, system-ui, sans-serif;
-  --avatar-cap-height: 0.7;
 }
 ```
 

src/frontend/src/components/Avatar.tsx

@@ -1,5 +1,5 @@
 import { css, cva, RecipeVariantProps } from '@/styled-system/css'
-import React, { useMemo } from 'react'
+import React, { useLayoutEffect, useMemo } from 'react'
 
 const avatar = cva({
   base: {
@@ -28,17 +28,24 @@ const avatar = cva({
   },
 })
 
+// Instantiating a segmenter is expensive; create it once and reuse it.
 const graphemeSegmenter =
   typeof Intl !== 'undefined' && 'Segmenter' in Intl
     ? new Intl.Segmenter(undefined, { granularity: 'grapheme' })
     : undefined
 
+/**
+ * Returns the first user-perceived character. Some Unicode characters span
+ * multiple UTF-16 code units, so a naive index into the string can split them
+ * and yield a broken glyph.
+ */
 const getFirstGrapheme = (value: string): string => {
   if (!value) return ''
   if (graphemeSegmenter) {
     const [first] = graphemeSegmenter.segment(value)
     return first?.segment ?? ''
   }
+  // Fallback: keeps single code points intact (including surrogate pairs).
   return Array.from(value)[0] ?? ''
 }
 
@@ -59,6 +66,36 @@ export type AvatarProps = React.HTMLAttributes<HTMLDivElement> & {
 export const Avatar = React.memo(
   ({ name, bgColor, context, notification, style, ...props }: AvatarProps) => {
     const initials = useMemo(() => getInitials(name), [name])
+    const textRef = React.useRef<SVGTextElement>(null)
+    const [offsetY, setOffsetY] = React.useState(0)
+
+    // Optically center the initials: measure the ink bounding box of the
+    // rendered glyphs and shift them so the box's center sits at the middle
+    // of the viewBox. Works for any font, weight or glyph shape, unlike a
+    // hand-tuned dy offset. getBBox() is in local (pre-transform)
+    // coordinates, so applying the translation never changes the measure.
+    useLayoutEffect(() => {
+      const text = textRef.current
+      if (!text) return
+
+      const center = () => {
+        const box = text.getBBox()
+        // A hidden element measures as an empty box; keep the default then.
+        if (box.height === 0) return
+        setOffsetY(50 - (box.y + box.height / 2))
+      }
+
+      center()
+      // Glyph metrics can change once webfonts finish loading.
+      let cancelled = false
+      document.fonts?.ready.then(() => {
+        if (!cancelled) center()
+      })
+      return () => {
+        cancelled = true
+      }
+    }, [initials])
+
     return (
       <div
         style={{ backgroundColor: bgColor, ...style }}
@@ -71,16 +108,15 @@ export const Avatar = React.memo(
           className={css({ width: '100%', height: '100%', display: 'block' })}
         >
           <text
+            ref={textRef}
             x="50"
-            y={50}
+            y="50"
+            transform={`translate(0 ${offsetY})`}
             textAnchor="middle"
+            dominantBaseline="central"
             fontSize="52"
             fontWeight="500"
             fill="currentColor"
-            className={css({
-              transform:
-                'translateY(calc(var(--avatar-cap-height, 0.7) * 0.5em))',
-            })}
           >
             {initials}
           </text>

src/frontend/src/styles/index.css

@@ -6,10 +6,6 @@ body,
   height: 100%;
 }
 
-:root {
-  --avatar-cap-height: 0.7;
-}
-
 html.font-lexend {
   --fonts-sans: 'Lexend Variable', ui-sans-serif, system-ui, sans-serif;
 }