diff --git a/web/src/components/layout/WorkspaceShell.tsx b/web/src/components/layout/WorkspaceShell.tsx
new file mode 100644
index 0000000..4dc3b91
--- /dev/null
+++ b/web/src/components/layout/WorkspaceShell.tsx
@@ -0,0 +1,112 @@
+import { Panel, PanelGroup, PanelResizeHandle } from "react-resizable-panels";
+import { PanelLeftClose, PanelLeftOpen, Terminal } from "lucide-react";
+
+import { Button } from "@/components/ui/button";
+import { Separator } from "@/components/ui/separator";
+import { FileExplorerPanel } from "@/components/workspace/FileExplorerPanel";
+import { StatusBar } from "@/components/workspace/StatusBar";
+import { useWorkspaceUiStore } from "@/lib/store/workspace-ui-store";
+import {
+  findFileByPath,
+  type MockFileNode,
+} from "@/pages/workspace/mock-data";
+
+interface WorkspaceShellProps {
+  files: MockFileNode[];
+}
+
+export function WorkspaceShell({ files }: WorkspaceShellProps) {
+  const activeFilePath = useWorkspaceUiStore((s) => s.activeFilePath);
+  const sidebarCollapsed = useWorkspaceUiStore((s) => s.sidebarCollapsed);
+  const terminalVisible = useWorkspaceUiStore((s) => s.terminalVisible);
+  const toggleSidebar = useWorkspaceUiStore((s) => s.toggleSidebar);
+  const toggleTerminal = useWorkspaceUiStore((s) => s.toggleTerminal);
+  const activeFile = findFileByPath(files, activeFilePath);
+
+  return (
+    <div className="flex h-full w-full flex-col bg-background text-foreground">
+      {/* Toolbar */}
+      <header className="flex h-9 shrink-0 items-center border-b border-border bg-sidebar px-3">
+        <h1 className="text-sm font-semibold">codespace</h1>
+        <Separator orientation="vertical" className="mx-3 h-4" />
+        <div className="flex items-center gap-1">
+          <Button
+            variant="ghost"
+            size="sm"
+            className="h-7 px-2 text-xs"
+            onClick={toggleSidebar}
+          >
+            {sidebarCollapsed ? (
+              <PanelLeftOpen className="size-4" aria-hidden="true" />
+            ) : (
+              <PanelLeftClose className="size-4" aria-hidden="true" />
+            )}
+          </Button>
+          <Button
+            variant="ghost"
+            size="sm"
+            className="h-7 px-2 text-xs"
+            onClick={toggleTerminal}
+          >
+            <Terminal className="size-4" aria-hidden="true" />
+          </Button>
+        </div>
+      </header>
+
+      {/* Main layout */}
+      <div className="flex min-h-0 flex-1">
+        <PanelGroup direction="horizontal" className="flex-1">
+          {/* Sidebar */}
+          {!sidebarCollapsed && (
+            <>
+              <Panel defaultSize={18} minSize={12} maxSize={30}>
+                <FileExplorerPanel files={files} />
+              </Panel>
+              <PanelResizeHandle className="w-1 bg-border transition-colors hover:bg-accent" />
+            </>
+          )}
+
+          {/* Main content area */}
+          <Panel>
+            <PanelGroup direction="vertical">
+              {/* Editor placeholder */}
+              <Panel>
+                <div className="flex h-full w-full items-center justify-center border-r border-border text-sm text-muted-foreground">
+                  <div className="text-center">
+                    <p className="mb-2">Editor placeholder</p>
+                    <div className="space-y-1 text-xs">
+                      <p>
+                        Active file:{" "}
+                        <code className="text-foreground">{activeFilePath}</code>
+                      </p>
+                      <p className="text-muted-foreground">
+                        {activeFile
+                          ? `${activeFile.name} | ${activeFile.language ?? "plain text"} | ${activeFile.kind}`
+                          : "No matching mock file"}
+                      </p>
+                    </div>
+                  </div>
+                </div>
+              </Panel>
+
+              {/* Terminal panel */}
+              {terminalVisible && (
+                <>
+                  <PanelResizeHandle className="h-1 bg-border transition-colors hover:bg-accent" />
+                  <Panel defaultSize={30} minSize={10} maxSize={70}>
+                    <div className="flex h-full w-full items-center justify-center border-r border-border text-sm text-muted-foreground">
+                      Terminal placeholder
+                    </div>
+                  </Panel>
+                </>
+              )}
+            </PanelGroup>
+          </Panel>
+        </PanelGroup>
+      </div>
+
+      {/* Status bar */}
+      <StatusBar activeFilePath={activeFilePath} />
+    </div>
+  );
+}
diff --git a/web/src/components/workspace/FileExplorerPanel.tsx b/web/src/components/workspace/FileExplorerPanel.tsx
new file mode 100644
index 0000000..809a0c2
--- /dev/null
+++ b/web/src/components/workspace/FileExplorerPanel.tsx
@@ -0,0 +1,99 @@
+import { ChevronRight, FileCode2, Folder } from "lucide-react";
+
+import { ScrollArea } from "@/components/ui/scroll-area";
+import { useWorkspaceUiStore } from "@/lib/store/workspace-ui-store";
+import { cn } from "@/lib/utils";
+import type { MockFileNode } from "@/pages/workspace/mock-data";
+
+interface FileExplorerPanelProps {
+  files: MockFileNode[];
+}
+
+interface FileTreeNodeProps {
+  node: MockFileNode;
+  depth: number;
+  activeFilePath: string;
+  onSelectFile: (path: string) => void;
+}
+
+function FileTreeNode({
+  node,
+  depth,
+  activeFilePath,
+  onSelectFile,
+}: FileTreeNodeProps) {
+  const isFile = node.kind === "file";
+  const isActive = isFile && node.path === activeFilePath;
+  const paddingLeft = `${depth * 0.875 + 0.75}rem`;
+
+  return (
+    <li>
+      <button
+        type="button"
+        disabled={!isFile}
+        onClick={() => isFile && onSelectFile(node.path)}
+        className={cn(
+          "flex h-7 w-full items-center gap-1.5 truncate px-2 text-left text-xs text-muted-foreground transition-colors",
+          isFile && "hover:bg-accent hover:text-accent-foreground",
+          !isFile && "cursor-default text-foreground",
+          isActive && "bg-accent text-accent-foreground",
+        )}
+        style={{ paddingLeft }}
+      >
+        {isFile ? (
+          <FileCode2 className="size-3.5 shrink-0" aria-hidden="true" />
+        ) : (
+          <>
+            <ChevronRight
+              className="size-3 shrink-0 rotate-90"
+              aria-hidden="true"
+            />
+            <Folder className="size-3.5 shrink-0" aria-hidden="true" />
+          </>
+        )}
+        <span className="truncate">{node.name}</span>
+      </button>
+      {node.children?.length ? (
+        <ul>
+          {node.children.map((child) => (
+            <FileTreeNode
+              key={child.path}
+              node={child}
+              depth={depth + 1}
+              activeFilePath={activeFilePath}
+              onSelectFile={onSelectFile}
+            />
+          ))}
+        </ul>
+      ) : null}
+    </li>
+  );
+}
+
+export function FileExplorerPanel({ files }: FileExplorerPanelProps) {
+  const activeFilePath = useWorkspaceUiStore((s) => s.activeFilePath);
+  const setActiveFilePath = useWorkspaceUiStore((s) => s.setActiveFilePath);
+
+  return (
+    <aside className="flex h-full min-h-0 flex-col bg-sidebar text-sidebar-foreground">
+      <div className="flex h-9 shrink-0 items-center border-b border-sidebar-border px-3 text-[11px] font-semibold uppercase text-muted-foreground">
+        Explorer
+      </div>
+      <ScrollArea className="min-h-0 flex-1">
+        <nav className="py-2" aria-label="Workspace files">
+          <ul>
+            {files.map((node) => (
+              <FileTreeNode
+                key={node.path}
+                node={node}
+                depth={0}
+                activeFilePath={activeFilePath}
+                onSelectFile={setActiveFilePath}
+              />
+            ))}
+          </ul>
+        </nav>
+      </ScrollArea>
+    </aside>
+  );
+}
diff --git a/web/src/components/workspace/StatusBar.tsx b/web/src/components/workspace/StatusBar.tsx
new file mode 100644
index 0000000..cd2e632
--- /dev/null
+++ b/web/src/components/workspace/StatusBar.tsx
@@ -0,0 +1,39 @@
+import { Terminal, FileCode2 } from "lucide-react";
+
+import { Separator } from "@/components/ui/separator";
+import { cn } from "@/lib/utils";
+import { useWorkspaceUiStore } from "@/lib/store/workspace-ui-store";
+
+interface StatusBarProps {
+  activeFilePath: string;
+}
+
+export function StatusBar({ activeFilePath }: StatusBarProps) {
+  const terminalVisible = useWorkspaceUiStore((s) => s.terminalVisible);
+  const toggleTerminal = useWorkspaceUiStore((s) => s.toggleTerminal);
+
+  return (
+    <footer className="flex h-6 shrink-0 items-center border-t border-border bg-sidebar px-3 text-[11px] text-muted-foreground">
+      <div className="flex items-center gap-2">
+        <FileCode2 className="size-3" aria-hidden="true" />
+        <span className="truncate max-w-48">{activeFilePath}</span>
+      </div>
+      <Separator orientation="vertical" className="mx-2 h-3" />
+      <span className="font-medium">codespace</span>
+      <div className="ml-auto flex items-center gap-1">
+        <button
+          type="button"
+          onClick={toggleTerminal}
+          className={cn(
+            "flex items-center gap-1 rounded px-1 py-0.5 transition-colors hover:bg-accent hover:text-accent-foreground",
+            terminalVisible && "text-foreground",
+          )}
+        >
+          <Terminal className="size-3" aria-hidden="true" />
+          <span>Terminal</span>
+          <span>{terminalVisible ? "Visible" : "Hidden"}</span>
+        </button>
+      </div>
+    </footer>
+  );
+}
diff --git a/web/src/pages/workspace/WorkspacePage.tsx b/web/src/pages/workspace/WorkspacePage.tsx
index 7f0316e..93e4ec9 100644
--- a/web/src/pages/workspace/WorkspacePage.tsx
+++ b/web/src/pages/workspace/WorkspacePage.tsx
@@ -1,28 +1,6 @@
-import { findFileByPath, mockWorkspaceFiles } from "@/pages/workspace/mock-data";
-import { useWorkspaceUiStore } from "@/lib/store/workspace-ui-store";
+import { mockWorkspaceFiles } from "@/pages/workspace/mock-data";
+import { WorkspaceShell } from "@/components/layout/WorkspaceShell";
 
 export function WorkspacePage() {
-  const activeFilePath = useWorkspaceUiStore((s) => s.activeFilePath);
-  const activeFile = findFileByPath(mockWorkspaceFiles, activeFilePath);
-
-  return (
-    <div className="flex h-full flex-col bg-background text-foreground">
-      <header className="border-b border-border px-4 py-2">
-        <h1 className="text-sm font-semibold">Codespace Workspace</h1>
-      </header>
-      <div className="flex-1 overflow-auto p-4">
-        <p className="text-sm text-muted-foreground">
-          Active file: <code className="text-foreground">{activeFilePath}</code>
-        </p>
-        <p className="mt-2 text-sm text-muted-foreground">
-          Mock file match:{" "}
-          <code className="text-foreground">
-            {activeFile
-              ? `${activeFile.name} (${activeFile.language ?? activeFile.kind})`
-              : "not found"}
-          </code>
-        </p>
-      </div>
-    </div>
-  );
+  return <WorkspaceShell files={mockWorkspaceFiles} />;
 }