Style channel header navigation (#889)

desktop/src/features/channels/ui/AgentSessionThreadPanel.tsx

@@ -55,6 +55,7 @@ export function AgentSessionThreadPanel({
   const avatarUrl = profiles?.[agent.pubkey.toLowerCase()]?.avatarUrl ?? null;
   const isOverlay = useIsThreadPanelOverlay();
   const isFloatingOverlay = isOverlay && !isSinglePanelView;
+  const usesChannelSplitChrome = !isOverlay && !isSinglePanelView;
   useEscapeKey(onClose, isOverlay || isSinglePanelView);
 
   const { ref: scrollRef, onScroll } = useStickToBottom<HTMLDivElement>();
@@ -111,7 +112,10 @@ export function AgentSessionThreadPanel({
         {!isOverlay ? (
           <div
             aria-hidden="true"
-            className="pointer-events-none absolute inset-x-0 top-0 z-40 h-[76px] bg-background/75 backdrop-blur-md before:absolute before:left-0 before:right-0 before:top-10 before:h-px before:bg-border/35 after:absolute after:bottom-0 after:-left-px after:top-10 after:w-px after:bg-border/80 supports-[backdrop-filter]:bg-background/65 dark:bg-background/45 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/35"
+            className={cn(
+              "pointer-events-none absolute inset-x-0 top-0 z-40 bg-background/75 backdrop-blur-md before:absolute before:left-0 before:right-0 before:top-10 before:h-px before:bg-border/35 after:absolute after:bottom-0 after:-left-px after:top-10 after:w-px after:bg-border/80 supports-[backdrop-filter]:bg-background/65 dark:bg-background/45 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/35",
+              usesChannelSplitChrome ? "h-[92px]" : "h-[76px]",
+            )}
           />
         ) : null}
 
@@ -122,7 +126,7 @@ export function AgentSessionThreadPanel({
               ? `relative ${PANEL_SINGLE_COLUMN_HEADER_LAYER_CLASS} -mb-[76px] min-h-[76px] shrink-0 gap-[10px] bg-background/80 pb-[4px] pl-[16px] pr-[8px] pt-[42px] backdrop-blur-md supports-[backdrop-filter]:bg-background/70 sm:pl-[24px] sm:pr-[12px] dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55`
               : isOverlay
                 ? "relative z-50 min-h-[44px] shrink-0 gap-3 bg-background/80 px-3 py-[6px] backdrop-blur-md supports-[backdrop-filter]:bg-background/70 dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55"
-                : "absolute inset-x-0 top-[42px] z-50 min-h-[32px] gap-3 px-3 py-[4px]",
+                : "absolute inset-x-0 top-[48px] z-50 h-[32px] gap-[10px] py-0 pl-[16px] pr-[8px] sm:pr-[12px]",
           )}
           data-tauri-drag-region
         >
@@ -139,7 +143,14 @@ export function AgentSessionThreadPanel({
                 displayName={agent.name}
                 size="xs"
               />
-              <h2 className="min-w-0 flex-1 translate-y-px truncate text-sm font-semibold leading-5 tracking-tight">
+              <h2
+                className={cn(
+                  "min-w-0 flex-1 translate-y-px truncate font-semibold tracking-tight",
+                  usesChannelSplitChrome
+                    ? "text-base leading-6"
+                    : "text-sm leading-5",
+                )}
+              >
                 {agent.name}
               </h2>
             </div>
@@ -186,14 +197,22 @@ export function AgentSessionThreadPanel({
               ) : null}
               <Button
                 aria-label="Close activity panel"
-                className="h-6 w-6 text-foreground hover:bg-muted/60 hover:text-foreground"
+                className={cn(
+                  usesChannelSplitChrome
+                    ? "h-8 w-8 rounded-lg border border-border/40 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5"
+                    : "h-6 w-6 text-foreground hover:bg-muted/60 hover:text-foreground",
+                )}
                 data-testid="agent-session-close"
                 onClick={onClose}
                 size="icon"
                 type="button"
                 variant="ghost"
               >
-                <X className="h-3.5 w-3.5" />
+                <X
+                  className={cn(
+                    usesChannelSplitChrome ? "size-5" : "h-3.5 w-3.5",
+                  )}
+                />
               </Button>
             </div>
           </div>
@@ -204,10 +223,13 @@ export function AgentSessionThreadPanel({
           onScroll={onScroll}
           className={cn(
             "min-h-0 flex-1 overflow-y-auto px-3 pb-4",
-            // Match MessageThreadPanel: single-panel mode has a 76px header
+            // Single-panel mode keeps the 76px local header; split panes sit
-            // (min-h-[76px] with -mb-[76px]), so the body must clear it. Only
+            // under the channel screen's 92px top chrome.
-            // the floating overlay (44px header) uses the smaller pt-4.
+            usesChannelSplitChrome
-            isSinglePanelView ? "pt-[76px]" : isOverlay ? "pt-4" : "pt-[76px]",
+              ? "pt-[92px]"
+              : isOverlay
+                ? "pt-4"
+                : "pt-[76px]",
           )}
         >
           <ManagedAgentSessionPanel

desktop/src/features/channels/ui/ChannelMembersBar.tsx

@@ -84,10 +84,10 @@ export function ChannelMembersBar({
 
   return (
     <React.Fragment>
-      <div className="flex items-center gap-1">
+      <div className="flex items-center gap-[6px]">
         <Button
           aria-label="Add agent"
-          className="h-7 w-7 rounded-full"
+          className="h-8 w-8 rounded-lg border border-border/40 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5"
           data-testid="channel-add-bot-trigger"
           disabled={!canAddAgents}
           onClick={() => {
@@ -95,27 +95,27 @@ export function ChannelMembersBar({
           }}
           size="icon"
           type="button"
-          variant="outline"
+          variant="ghost"
         >
-          <Plus className="h-3 w-3" />
+          <Plus className="size-5" />
         </Button>
 
         <Button
           aria-label={`View channel members (${memberCount})`}
-          className="h-7 gap-1 rounded-full px-2"
+          className="h-8 gap-1 rounded-lg border border-border/40 px-2.5 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5"
           data-testid="channel-members-trigger"
           onClick={onToggleMembers}
           type="button"
-          variant="outline"
+          variant="ghost"
         >
-          <Users className="h-3 w-3" />
+          <Users className="size-5" />
           <span className="min-w-[1ch] text-[11px] font-medium tabular-nums">
             {memberCount}
           </span>
         </Button>
 
         <HuddleIndicator
-          className="h-7 w-7"
+          className="h-8 w-8"
           channelId={channel.id}
           onStart={async () => {
             try {
@@ -132,14 +132,14 @@ export function ChannelMembersBar({
 
         <Button
           aria-label="Manage channel"
-          className="h-7 w-7 rounded-full"
+          className="h-8 w-8 rounded-lg border border-border/40 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5"
           data-testid="channel-management-trigger"
           onClick={onManageChannel}
           size="icon"
           type="button"
-          variant="outline"
+          variant="ghost"
         >
-          <Settings2 className="h-3 w-3" />
+          <Settings2 className="size-5" />
         </Button>
       </div>
 

desktop/src/features/channels/ui/ChannelScreen.tsx

@@ -44,8 +44,12 @@ import { useChannelFind } from "@/features/search/useChannelFind";
 import { ViewLoadingFallback } from "@/shared/ui/ViewLoadingFallback";
 import { AgentSessionProvider } from "@/shared/context/AgentSessionContext";
 import { ProfilePanelProvider } from "@/shared/context/ProfilePanelContext";
-import { useElementWidthBreakpoint } from "@/shared/hooks/use-mobile";
 import {
+  useElementWidthBreakpoint,
+  useIsThreadPanelOverlay,
+} from "@/shared/hooks/use-mobile";
+import {
+  THREAD_PANEL_MIN_WIDTH_PX,
   THREAD_PANEL_SINGLE_COLUMN_BREAKPOINT_PX,
   useThreadPanelWidth,
 } from "@/shared/hooks/useThreadPanelWidth";
@@ -87,6 +91,7 @@ export function ChannelScreen({
     widthPx: threadPanelWidthPx,
   } = useThreadPanelWidth();
   const [isMembersSidebarOpen, setIsMembersSidebarOpen] = React.useState(false);
+  const isThreadPanelOverlay = useIsThreadPanelOverlay();
   const [channelContentRef, isNarrowPanelViewport] =
     useElementWidthBreakpoint<HTMLDivElement>(
       THREAD_PANEL_SINGLE_COLUMN_BREAKPOINT_PX,
@@ -435,6 +440,15 @@ export function ChannelScreen({
     Boolean(
       openThreadHeadMessage || openAgentSessionPubkey || profilePanelPubkey,
     );
+  const hasSplitRightPanel =
+    !isSinglePanelView &&
+    !isThreadPanelOverlay &&
+    Boolean(
+      openThreadHeadMessage || openAgentSessionPubkey || profilePanelPubkey,
+    );
+  const headerActionsRightInset = hasSplitRightPanel
+    ? `min(${threadPanelWidthPx}px, calc(100% - ${THREAD_PANEL_MIN_WIDTH_PX}px))`
+    : undefined;
 
   return (
     <AgentSessionProvider onOpenAgentSession={handleOpenAgentSession}>
@@ -443,6 +457,7 @@ export function ChannelScreen({
           activeChannel={activeChannel}
           activeChannelEphemeralDisplay={activeChannelEphemeralDisplay}
           activeChannelTitle={activeChannelTitle}
+          actionsRightInset={headerActionsRightInset}
           activeDmPresenceStatus={activeDmPresenceStatus}
           currentPubkey={currentPubkey}
           isJoining={joinChannelMutation.isPending}

desktop/src/features/channels/ui/ChannelScreenHeader.tsx

@@ -14,6 +14,7 @@ type ChannelScreenHeaderProps = {
   activeChannel: Channel | null;
   activeChannelEphemeralDisplay: EphemeralChannelDisplay | null;
   activeChannelTitle: string;
+  actionsRightInset?: string;
   activeDmPresenceStatus: PresenceStatus | null;
   currentPubkey?: string;
   isJoining?: boolean;
@@ -27,6 +28,7 @@ export function ChannelScreenHeader({
   activeChannel,
   activeChannelEphemeralDisplay,
   activeChannelTitle,
+  actionsRightInset,
   activeDmPresenceStatus,
   currentPubkey,
   isJoining = false,
@@ -79,10 +81,10 @@ export function ChannelScreenHeader({
 
   return (
     <ChatHeader
-      actionsPlacement="top-right"
       belowSystemChrome
       density="compact"
       actions={actions}
+      actionsRightInset={actionsRightInset}
       channelType={activeChannel?.channelType}
       description={getChannelDescription(activeChannel)}
       statusBadge={

desktop/src/features/chat/ui/ChatHeader.tsx

@@ -19,6 +19,7 @@ import { cn } from "@/shared/lib/cn";
 type ChatHeaderProps = {
   actions?: React.ReactNode;
   actionsPlacement?: "inline" | "top-right";
+  actionsRightInset?: string;
   belowSystemChrome?: boolean;
   density?: "default" | "compact";
   title: string;
@@ -80,6 +81,7 @@ function ChannelIcon({
 export function ChatHeader({
   actions,
   actionsPlacement = "inline",
+  actionsRightInset,
   belowSystemChrome = false,
   density = "default",
   title,
@@ -101,10 +103,8 @@ export function ChatHeader({
   const header = (
     <header
       className={cn(
-        "relative z-30 flex min-w-0 shrink-0 cursor-default select-none items-center gap-[10px] bg-transparent pl-[16px] pr-[8px] transition-[margin,padding] duration-200 ease-linear sm:pl-[24px] sm:pr-[12px]",
+        "pointer-events-auto relative z-30 flex min-w-0 shrink-0 cursor-default select-none items-center gap-[10px] bg-transparent pl-[16px] pr-[8px] transition-[margin,padding] duration-200 ease-linear sm:pl-[24px] sm:pr-[12px]",
-        density === "compact"
+        density === "compact" ? "h-[32px] py-0" : "min-h-[44px] py-[6px]",
-          ? "min-h-[32px] py-[4px]"
-          : "min-h-[44px] py-[6px]",
         overlaysContent && !belowSystemChrome && "-mb-[44px]",
       )}
       data-testid="chat-header"
@@ -118,7 +118,7 @@ export function ChatHeader({
             visibility={visibility}
           />
           <h1
-            className="min-w-0 translate-y-px truncate text-sm font-semibold leading-5 tracking-tight"
+            className="min-w-0 translate-y-px truncate text-base font-semibold leading-6 tracking-tight"
             data-testid="chat-title"
             title={trimmedDescription || undefined}
           >
@@ -137,7 +137,12 @@ export function ChatHeader({
           createPortal(topRightActions, document.body)
         )
       ) : (
-        <div className="flex shrink-0 items-center gap-1">
+        <div
+          className="flex shrink-0 items-center gap-1"
+          style={
+            actionsRightInset ? { marginRight: actionsRightInset } : undefined
+          }
+        >
           <UpdateIndicator />
           {actions ? <div className="shrink-0">{actions}</div> : null}
         </div>
@@ -150,7 +155,7 @@ export function ChatHeader({
   }
 
   return (
-    <div className="relative z-30 h-[76px] -mb-[76px] bg-background/80 pt-[42px] backdrop-blur-md supports-[backdrop-filter]:bg-background/70 dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55">
+    <div className="pointer-events-none relative z-30 h-[92px] -mb-[92px] bg-background/80 pb-[9px] pt-[48px] backdrop-blur-md after:absolute after:inset-x-0 after:bottom-0 after:h-px after:bg-border/35 after:content-[''] supports-[backdrop-filter]:bg-background/70 dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55">
       {header}
     </div>
   );

desktop/src/features/huddle/components/HuddleIndicator.tsx

@@ -230,15 +230,18 @@ export function HuddleIndicator({
       <>
         <Button
           aria-label="Start huddle"
-          className={cn("h-7 w-7 rounded-full", className)}
+          className={cn(
+            "h-8 w-8 rounded-lg border border-border/40 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5",
+            className,
+          )}
           data-testid="channel-start-huddle-trigger"
           disabled={startDisabled || isStarting}
           onClick={() => headphonesGate.gate(() => onStart())}
           size="icon"
           type="button"
-          variant="outline"
+          variant="ghost"
         >
-          <Headphones className="h-3 w-3" />
+          <Headphones className="size-5" />
         </Button>
         {gateDialog}
       </>
@@ -270,15 +273,18 @@ export function HuddleIndicator({
         <TooltipTrigger asChild>
           <Button
             aria-label={`Join active huddle (${participantCount} participant${participantCount !== 1 ? "s" : ""})`}
-            className={cn("relative h-7 w-7 rounded-full", className)}
+            className={cn(
+              "relative h-8 w-8 rounded-lg border border-border/40 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5",
+              className,
+            )}
             disabled={isJoining || isStarting}
             onClick={() => headphonesGate.gate(() => void doJoin())}
             size="icon"
             type="button"
-            variant="outline"
+            variant="ghost"
           >
-            <Headphones className="h-3 w-3 text-muted-foreground" />
+            <Headphones className="size-5 text-muted-foreground" />
-            <span className="absolute inset-0 animate-pulse rounded-full ring-2 ring-border/70" />
+            <span className="absolute inset-0 animate-pulse rounded-lg ring-2 ring-border/70" />
             {/* Participant count badge */}
             {participantCount > 0 && (
               <span className="absolute -right-1 -top-1 flex h-3.5 min-w-3.5 items-center justify-center rounded-full border border-border bg-background px-0.5 text-[9px] font-bold text-muted-foreground">

desktop/src/features/messages/ui/DayDivider.tsx

@@ -2,11 +2,11 @@ export function DayDivider({ label }: { label: string }) {
   return (
     <section
       aria-label={label}
-      className="sticky top-[76px] z-[5] flex justify-center py-1"
+      className="sticky top-[92px] z-[5] flex justify-center py-1"
       data-testid="message-timeline-day-divider"
       data-day-label={label}
     >
-      <p className="shrink-0 rounded-lg border border-border/70 bg-background/95 px-2 py-1 text-[10px] font-medium tracking-[0.02em] text-muted-foreground/70 shadow-xs backdrop-blur-sm">
+      <p className="relative z-10 shrink-0 rounded-lg border border-border/70 bg-background/95 px-2 py-1 text-[10px] font-medium tracking-[0.02em] text-muted-foreground/70 shadow-xs backdrop-blur-sm">
         {label}
       </p>
     </section>

desktop/src/features/messages/ui/MessageReactions.tsx

@@ -12,7 +12,7 @@ import { Tooltip, TooltipContent, TooltipTrigger } from "@/shared/ui/tooltip";
 
 const REACTION_PILL_BASE_CLASSES =
   "inline-flex h-8 items-center rounded-full border text-xs font-medium leading-none transition-colors";
-const REACTION_GLYPH_CLASSES = "-translate-y-px h-3.5 w-3.5 text-sm";
+const REACTION_GLYPH_CLASSES = "h-3.5 w-3.5 translate-y-px text-sm";
 const REACTION_PILL_HOVER_CLASSES =
   "hover:bg-primary/10 hover:text-foreground focus-visible:bg-primary/10 focus-visible:outline-hidden focus-visible:ring-2 focus-visible:ring-ring";
 

desktop/src/features/messages/ui/MessageThreadPanel.tsx

@@ -127,6 +127,7 @@ export function MessageThreadPanel({
   const threadComposerWrapperRef = React.useRef<HTMLDivElement>(null);
   const isOverlay = useIsThreadPanelOverlay();
   const isFloatingOverlay = isOverlay && !isSinglePanelView;
+  const usesChannelSplitChrome = !isOverlay && !isSinglePanelView;
   useEscapeKey(onClose, isOverlay || isSinglePanelView);
   useComposerHeightPadding(
     threadBodyRef,
@@ -207,7 +208,10 @@ export function MessageThreadPanel({
         {!isOverlay ? (
           <div
             aria-hidden="true"
-            className="pointer-events-none absolute inset-x-0 top-0 z-40 h-[76px] bg-transparent after:absolute after:bottom-0 after:-left-px after:top-10 after:w-px after:bg-border/45 after:transition-colors peer-hover/thread-resize:after:bg-border/80 peer-focus-visible/thread-resize:after:bg-border/80"
+            className={cn(
+              "pointer-events-none absolute inset-x-0 top-0 z-40 bg-transparent after:absolute after:bottom-0 after:-left-px after:top-10 after:w-px after:bg-border/45 after:transition-colors peer-hover/thread-resize:after:bg-border/80 peer-focus-visible/thread-resize:after:bg-border/80",
+              usesChannelSplitChrome ? "h-[92px]" : "h-[76px]",
+            )}
           />
         ) : null}
 
@@ -215,10 +219,10 @@ export function MessageThreadPanel({
           className={cn(
             "flex cursor-default select-none items-center",
             isSinglePanelView
-              ? `relative ${PANEL_SINGLE_COLUMN_HEADER_LAYER_CLASS} -mb-[76px] min-h-[76px] shrink-0 gap-[10px] bg-background/80 pb-[3px] pl-[16px] pr-[8px] pt-[43px] backdrop-blur-md supports-[backdrop-filter]:bg-background/70 sm:pl-[24px] sm:pr-[12px] dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55`
+              ? `relative ${PANEL_SINGLE_COLUMN_HEADER_LAYER_CLASS} -mb-[76px] min-h-[76px] shrink-0 gap-[10px] bg-background/80 pb-[3px] pl-[16px] pr-[8px] pt-[43px] backdrop-blur-md supports-[backdrop-filter]:bg-background/70 sm:pr-[12px] dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55`
               : isOverlay
                 ? "relative z-50 min-h-[44px] shrink-0 gap-3 bg-background/80 px-3 py-[6px] backdrop-blur-md supports-[backdrop-filter]:bg-background/70 dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55"
-                : "absolute inset-x-0 top-[42px] z-50 min-h-[32px] gap-3 px-3 py-[4px]",
+                : "absolute inset-x-0 top-[48px] z-50 h-[32px] gap-[10px] py-0 pl-[16px] pr-[8px] sm:pr-[12px]",
           )}
           data-tauri-drag-region
         >
@@ -243,27 +247,27 @@ export function MessageThreadPanel({
                 </Button>
               </div>
             ) : null}
-            <h2 className="translate-y-px text-sm font-semibold leading-5 tracking-tight">
+            <h2 className="translate-y-px text-base font-semibold leading-6 tracking-tight">
               Thread
             </h2>
           </div>
           <Button
             aria-label="Close thread"
-            className="ml-auto h-4 w-4 rounded-full text-foreground hover:bg-muted/60 hover:text-foreground"
+            className="ml-auto h-8 w-8 rounded-lg border border-border/40 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5"
             data-testid="message-thread-close"
             onClick={onClose}
             size="icon"
             type="button"
             variant="ghost"
           >
-            <X className="h-2.5 w-2.5" />
+            <X className="size-5" />
           </Button>
         </div>
 
         <div
           className={cn(
             "min-h-0 flex-1 overflow-y-auto overflow-x-hidden overscroll-contain pb-24 [overflow-anchor:none]",
-            isSinglePanelView ? "pt-[76px]" : isOverlay ? "" : "pt-[76px]",
+            usesChannelSplitChrome ? "pt-[92px]" : isOverlay ? "" : "pt-[76px]",
           )}
           data-testid="message-thread-body"
           onScroll={syncScrollState}

desktop/src/features/messages/ui/MessageTimeline.tsx

@@ -148,7 +148,7 @@ export const MessageTimeline = React.memo(function MessageTimeline({
           ref={scrollContainerRef}
         >
           <div
-            className="flex w-full flex-col gap-2 pt-[76px]"
+            className="flex w-full flex-col gap-2 pt-[92px]"
             ref={contentRef}
           >
             <div ref={topSentinelRef} aria-hidden className="h-px" />

desktop/src/features/messages/ui/TimelineMessageList.tsx

@@ -189,7 +189,10 @@ export const TimelineMessageList = React.memo(function TimelineMessageList({
   }
 
   return dayGroups.map((group) => (
-    <section className="flex flex-col gap-2.5" key={group.key}>
+    <section
+      className="relative flex flex-col gap-2.5 before:absolute before:inset-x-0 before:top-[15px] before:h-px before:bg-border/35 before:content-['']"
+      key={group.key}
+    >
       <DayDivider label={group.label} />
       {group.elements}
     </section>

desktop/src/features/profile/ui/UserProfilePanel.tsx

@@ -106,6 +106,8 @@ export function UserProfilePanel({
 }: UserProfilePanelProps) {
   const isOverlay = useIsThreadPanelOverlay();
   const isFloatingOverlay = isOverlay && !isSinglePanelView;
+  const usesChannelSplitChrome =
+    splitPaneClamp && !isOverlay && !isSinglePanelView;
   useEscapeKey(onClose, isOverlay || isSinglePanelView);
 
   const profileQuery = useUserProfileQuery(pubkey);
@@ -239,7 +241,10 @@ export function UserProfilePanel({
         {!isOverlay ? (
           <div
             aria-hidden="true"
-            className="pointer-events-none absolute inset-x-0 top-0 z-40 h-[76px] bg-background/80 backdrop-blur-md after:absolute after:left-0 after:right-0 after:top-10 after:h-px after:bg-border/35 supports-[backdrop-filter]:bg-background/70 dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55"
+            className={cn(
+              "pointer-events-none absolute inset-x-0 top-0 z-40 bg-background/80 backdrop-blur-md after:absolute after:left-0 after:right-0 after:top-10 after:h-px after:bg-border/35 supports-[backdrop-filter]:bg-background/70 dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55",
+              usesChannelSplitChrome ? "h-[92px]" : "h-[76px]",
+            )}
           />
         ) : null}
 
@@ -250,32 +255,52 @@ export function UserProfilePanel({
               ? `relative ${PANEL_SINGLE_COLUMN_HEADER_LAYER_CLASS} -mb-[76px] min-h-[76px] shrink-0 gap-[10px] bg-transparent pb-[4px] pl-[16px] pr-[8px] pt-[42px] sm:pl-[24px] sm:pr-[12px]`
               : isOverlay
                 ? "relative z-50 min-h-[44px] shrink-0 gap-3 bg-background/80 px-3 py-[6px] backdrop-blur-md supports-[backdrop-filter]:bg-background/70 dark:bg-background/70 dark:backdrop-blur-xl dark:supports-[backdrop-filter]:bg-background/55"
-                : "absolute inset-x-0 top-[42px] z-50 min-h-[32px] gap-3 bg-transparent px-3 py-[4px] after:absolute after:bottom-0 after:-left-px after:top-0 after:w-px after:bg-border/45 after:transition-colors peer-hover/profile-resize:after:bg-border/80 peer-focus-visible/profile-resize:after:bg-border/80",
+                : cn(
+                    "absolute inset-x-0 z-50 bg-transparent after:absolute after:bottom-0 after:-left-px after:top-0 after:w-px after:bg-border/45 after:transition-colors peer-hover/profile-resize:after:bg-border/80 peer-focus-visible/profile-resize:after:bg-border/80",
+                    usesChannelSplitChrome
+                      ? "top-[48px] h-[32px] gap-[10px] py-0 pl-[16px] pr-[8px] sm:pr-[12px]"
+                      : "top-[42px] min-h-[32px] gap-3 px-3 py-[4px]",
+                  ),
           )}
           data-tauri-drag-region
         >
           <div className="flex min-w-0 items-center gap-1.5">
-            <h2 className="translate-y-px text-sm font-semibold leading-5 tracking-tight">
+            <h2
+              className={cn(
+                "translate-y-px font-semibold tracking-tight",
+                usesChannelSplitChrome
+                  ? "text-base leading-6"
+                  : "text-sm leading-5",
+              )}
+            >
               Profile
             </h2>
           </div>
           <Button
             aria-label="Close profile"
-            className="ml-auto h-4 w-4 rounded-full text-foreground hover:bg-muted/60 hover:text-foreground"
+            className={cn(
+              "ml-auto",
+              usesChannelSplitChrome
+                ? "h-8 w-8 rounded-lg border border-border/40 text-muted-foreground hover:bg-muted/70 hover:text-foreground [&_svg]:size-5"
+                : "h-4 w-4 rounded-full text-foreground hover:bg-muted/60 hover:text-foreground",
+            )}
             data-testid="user-profile-panel-close"
             onClick={onClose}
             size="icon"
             type="button"
             variant="ghost"
           >
-            <X className="h-2.5 w-2.5" />
+            <X
+              className={cn(usesChannelSplitChrome ? "size-5" : "h-2.5 w-2.5")}
+            />
           </Button>
         </div>
 
         <div
           className={cn(
             "min-h-0 flex-1 overflow-y-auto px-4 pb-6",
-            !isFloatingOverlay && "pt-[76px]",
+            !isFloatingOverlay &&
+              (usesChannelSplitChrome ? "pt-[92px]" : "pt-[76px]"),
           )}
         >
           <div className="flex flex-col items-center gap-4 pt-4">

desktop/src/features/sidebar/ui/SidebarSection.tsx

@@ -328,6 +328,7 @@ export function SidebarSection({
                     {channel.channelType === "dm" && onHideDm ? (
                       <SidebarMenuAction
                         aria-label="Close direct message"
+                        className="right-0 top-1/2 h-8 w-8 -translate-y-1/2 rounded-lg border border-border/40 [&>svg]:size-5 peer-data-[size=default]/menu-button:top-1/2 peer-data-[size=lg]/menu-button:top-1/2 peer-data-[size=sm]/menu-button:top-1/2"
                         data-testid={`hide-dm-${channel.name}`}
                         onClick={() => onHideDm(channel.id)}
                         showOnHover