diff --git a/apps/cockpit/src/app/cockpit.css b/apps/cockpit/src/app/cockpit.css
index 88e5c95b..5d7d9802 100644
--- a/apps/cockpit/src/app/cockpit.css
+++ b/apps/cockpit/src/app/cockpit.css
@@ -208,7 +208,6 @@ pre.shiki {
 /* Shared prose layer — docs + api + code mode content */
 .cockpit-prose {
   max-width: 42rem;
-  margin-inline: auto;
   font-size: 0.9rem;
   line-height: 1.7;
   color: var(--ds-text-secondary);
@@ -235,6 +234,34 @@ pre.shiki {
 .cockpit-prose table.params th { font-family: var(--font-mono), monospace; font-size: 0.6rem; letter-spacing: 0.06em; text-transform: uppercase; padding-bottom: 0.5rem; border-bottom: 1px solid var(--ds-border); }
 .cockpit-prose table.params td { padding: 0.5rem 0.75rem 0.5rem 0; border-bottom: 1px solid var(--ds-border); }
 
+/* Sidebar navigation items — bg-only active/hover, no left border */
+.cockpit-nav-item {
+  display: block;
+  padding: 5px 14px;
+  margin: 0 8px;
+  border-radius: 6px;
+  font-size: 0.825rem;
+  color: var(--ds-text-secondary);
+  text-decoration: none;
+  transition: background 0.15s ease, color 0.15s ease;
+}
+.cockpit-nav-item:hover { background: var(--ds-surface-dim); color: var(--ds-text-primary); }
+.cockpit-nav-item[aria-current="page"] { background: var(--ds-accent-surface); color: var(--ds-accent); }
+
+/* Sidebar group caret — matches the file-tree chevron */
+.cockpit-nav-caret {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 0.85rem;
+  height: 0.85rem;
+  color: var(--ds-text-muted);
+  flex: none;
+  transition: transform 150ms ease;
+}
+.cockpit-nav-caret svg { display: block; }
+.cockpit-nav-caret--open { transform: rotate(90deg); }
+
 /* Code-mode file tree */
 .cockpit-file-tree { list-style: none; padding: 0; margin: 0; font-size: 12px; line-height: 1.7; }
 .cockpit-file-tree ul { list-style: none; padding: 0; margin: 0; }
@@ -246,7 +273,18 @@ pre.shiki {
   border-left: 2px solid transparent; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
 }
 .cockpit-file-tree__folder { color: var(--ds-text-muted); display: flex; align-items: center; }
-.cockpit-file-tree__caret { font-size: 9px; color: var(--ds-text-muted); width: 0.65rem; flex-shrink: 0; }
+.cockpit-file-tree__caret {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 0.85rem;
+  height: 0.85rem;
+  color: var(--ds-text-muted);
+  flex: none;
+  transition: transform 150ms ease;
+}
+.cockpit-file-tree__caret svg { display: block; }
+.cockpit-file-tree__caret--open { transform: rotate(90deg); }
 .cockpit-file-tree__label { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
 .cockpit-file-tree__chip {
   font-family: var(--font-mono), monospace; font-size: 9px;
@@ -272,3 +310,39 @@ pre.shiki {
 .cockpit-tab-trigger:hover .cockpit-tab-trigger__close,
 .cockpit-tab-trigger[data-state="active"] .cockpit-tab-trigger__close { opacity: 1; }
 .cockpit-tab-trigger__close:hover { background: var(--ds-accent-surface); color: var(--ds-text-primary); }
+
+/* Code-mode editor pane — no chrome, no separate background, full-bleed under the tab strip. */
+.cockpit-code-pane {
+  min-width: 0;
+}
+.cockpit-code-pane pre.shiki {
+  background: transparent !important;
+  margin: 0;
+  border-radius: 0;
+  padding: 1rem 1.25rem;
+  font-size: 0.8125rem;
+  white-space: pre;
+  overflow-x: auto;
+  max-width: 100%;
+}
+
+/* Shiki dual-theme: light mode uses inline `color` (github-light), dark mode swaps to the --shiki-dark CSS variable (tokyo-night). */
+[data-theme="dark"] .shiki,
+[data-theme="dark"] .shiki span { color: var(--shiki-dark) !important; }
+[data-theme="dark"] .shiki { background-color: var(--shiki-dark-bg) !important; }
+[data-theme="dark"] .cockpit-code-pane .shiki { background-color: transparent !important; }
+.cockpit-code-pane--plain {
+  margin: 0;
+  padding: 1rem 1.25rem;
+  color: var(--ds-text-secondary);
+  font-family: var(--font-mono), "JetBrains Mono", monospace;
+  font-size: 0.8125rem;
+  line-height: 1.6;
+  white-space: pre-wrap;
+  max-width: 100%;
+}
+.cockpit-code-pane__empty {
+  padding: 1rem 1.25rem;
+  color: var(--ds-text-muted);
+  font-size: 0.875rem;
+}
diff --git a/apps/cockpit/src/components/branding/logo.spec.tsx b/apps/cockpit/src/components/branding/logo.spec.tsx
index 535b87c8..77154c3e 100644
--- a/apps/cockpit/src/components/branding/logo.spec.tsx
+++ b/apps/cockpit/src/components/branding/logo.spec.tsx
@@ -9,11 +9,6 @@ describe('Logo', () => {
     expect(html).toContain('Threadplane');
   });
 
-  it('renders the cockpit qualifier', () => {
-    const html = renderToStaticMarkup(<Logo />);
-    expect(html).toContain('cockpit');
-  });
-
   it('exposes a stable data-ui selector', () => {
     const html = renderToStaticMarkup(<Logo />);
     expect(html).toContain('data-ui="cockpit-logo"');
diff --git a/apps/cockpit/src/components/branding/logo.tsx b/apps/cockpit/src/components/branding/logo.tsx
index 64ff6dd2..fe39f2d0 100644
--- a/apps/cockpit/src/components/branding/logo.tsx
+++ b/apps/cockpit/src/components/branding/logo.tsx
@@ -13,9 +13,6 @@ export function Logo({ className, style, ...rest }: HTMLAttributes<HTMLSpanEleme
       <span style={{ fontFamily: 'var(--font-garamond), "EB Garamond", Georgia, serif', fontSize: 16, fontWeight: 600, color: 'var(--ds-text-primary)' }}>
         Threadplane
       </span>
-      <span style={{ fontFamily: 'var(--font-mono), "JetBrains Mono", monospace', fontSize: 12, color: 'var(--ds-text-muted)' }}>
-        cockpit
-      </span>
     </span>
   );
 }
diff --git a/apps/cockpit/src/components/cockpit-shell.tsx b/apps/cockpit/src/components/cockpit-shell.tsx
index 2c6956dc..85add0bc 100644
--- a/apps/cockpit/src/components/cockpit-shell.tsx
+++ b/apps/cockpit/src/components/cockpit-shell.tsx
@@ -79,11 +79,11 @@ export function CockpitShell({
         onClose={() => setIsSidebarOpen(false)}
       />
 
-      <section className="grid grid-rows-[auto_1fr] overflow-hidden bg-[var(--ds-surface)]">
+      <section className="grid grid-rows-[auto_1fr] grid-cols-[minmax(0,1fr)] overflow-hidden bg-[var(--ds-surface)]">
         <header
-          className="flex flex-col gap-2 md:flex-row md:items-center md:justify-between px-4 py-3 border-b border-[var(--ds-border)]"
+          className="flex items-center justify-between gap-3 px-4 py-3 border-b border-[var(--ds-border)]"
         >
-          <div className="flex items-center gap-3">
+          <div className="flex items-center gap-3 min-w-0">
             <button
               className="md:hidden"
               onClick={() => setIsSidebarOpen(true)}
@@ -93,9 +93,9 @@ export function CockpitShell({
             >
               <MenuIcon />
             </button>
-            <p className="hidden md:block text-[var(--ds-text-muted)] font-mono text-xs">{contextLabel}</p>
+            <p className="hidden md:block text-[var(--ds-text-muted)] font-mono text-xs truncate">{contextLabel}</p>
           </div>
-          <div className="overflow-x-auto -mx-4 px-4 md:mx-0 md:px-0">
+          <div className="shrink-0 overflow-x-auto">
             <ModeSwitcher
               modes={PRIMARY_MODES}
               activeMode={activeMode}
diff --git a/apps/cockpit/src/components/code-mode/code-mode.spec.tsx b/apps/cockpit/src/components/code-mode/code-mode.spec.tsx
index eceec097..97634d2e 100644
--- a/apps/cockpit/src/components/code-mode/code-mode.spec.tsx
+++ b/apps/cockpit/src/components/code-mode/code-mode.spec.tsx
@@ -2,11 +2,8 @@
 import React from 'react';
 import { act } from 'react';
 import { createRoot } from 'react-dom/client';
-import { afterEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it } from 'vitest';
 
-vi.mock('../../lib/analytics/client', () => ({ track: vi.fn() }));
-
-import { track } from '../../lib/analytics/client';
 import { CodeMode } from './code-mode';
 
 describe('CodeMode', () => {
@@ -18,7 +15,6 @@ describe('CodeMode', () => {
       root?.unmount();
     });
     container?.remove();
-    vi.clearAllMocks();
   });
 
   it('renders Shiki-highlighted HTML for the active file', () => {
@@ -47,8 +43,9 @@ describe('CodeMode', () => {
     });
 
     expect(container.querySelector('.shiki')).not.toBeNull();
-    const fileLabel = container.querySelector('.doc-codeblock__file');
-    expect(fileLabel?.textContent).toBe('page.tsx');
+    // The filename now lives in the tab strip (no chrome around the code body).
+    const activeTab = container.querySelector('[role="tab"][data-state="active"]');
+    expect((activeTab?.textContent ?? '').replace(/×/g, '').trim()).toBe('page.tsx');
     expect(container.textContent).toContain('export default function Page() {}');
 
     const tabs = Array.from(container.querySelectorAll('[role="tab"]'));
@@ -284,41 +281,4 @@ describe('CodeMode', () => {
     expect(tabs).toEqual(['b.ts']);
   });
 
-  it('fires cockpit:code_copied when the Copy button is clicked', () => {
-    container = document.createElement('div');
-    document.body.appendChild(container);
-    root = createRoot(container);
-
-    Object.assign(navigator, {
-      clipboard: { writeText: vi.fn(() => Promise.resolve()) },
-    });
-
-    act(() => {
-      root!.render(
-        <CodeMode
-          entryTitle="Test"
-          codeAssetPaths={['src/app.tsx']}
-          backendAssetPaths={[]}
-          codeFiles={{ 'src/app.tsx': '<pre class="shiki"><code>const x = 1;</code></pre>' }}
-          promptFiles={{}}
-          capability="streaming"
-        />,
-      );
-    });
-
-    const copyBtn = container.querySelector(
-      'button[aria-label^="Copy"]',
-    ) as HTMLButtonElement | null;
-    expect(copyBtn).not.toBeNull();
-
-    act(() => {
-      copyBtn!.click();
-    });
-
-    expect(track).toHaveBeenCalledWith('cockpit:code_copied', {
-      capability: 'streaming',
-      surface: 'code_mode',
-      file_path: 'src/app.tsx',
-    });
-  });
 });
diff --git a/apps/cockpit/src/components/code-mode/code-mode.tsx b/apps/cockpit/src/components/code-mode/code-mode.tsx
index 5e013fc6..9f532edc 100644
--- a/apps/cockpit/src/components/code-mode/code-mode.tsx
+++ b/apps/cockpit/src/components/code-mode/code-mode.tsx
@@ -2,7 +2,6 @@
 
 import React from 'react';
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
-import { track } from '../../lib/analytics/client';
 import { FileTree } from './file-tree';
 
 interface CodeModeProps {
@@ -19,38 +18,14 @@ const getTabLabel = (path: string): string => path.split('/').pop() ?? path;
 function CodeFileContent({
   path,
   content,
-  capability,
 }: {
   path: string;
   content: string | undefined;
-  capability?: string;
 }) {
   if (!content) {
-    return <p className="text-sm text-[var(--ds-text-muted)]">No source available for {getTabLabel(path)}</p>;
+    return <p className="cockpit-code-pane__empty">No source available for {getTabLabel(path)}</p>;
   }
-
-  const label = getTabLabel(path);
-  const dotIdx = label.lastIndexOf('.');
-  const ext = dotIdx > 0 ? label.slice(dotIdx + 1).toUpperCase() : '';
-
-  return (
-    <div className="doc-codeblock">
-      <div className="doc-codeblock__header">
-        <span className="doc-codeblock__file">{label}</span>
-        {ext ? <span className="doc-codeblock__lang">{ext}</span> : null}
-        <button
-          className="doc-codeblock__copy"
-          aria-label={`Copy ${label}`}
-          onClick={() => {
-            track('cockpit:code_copied', { capability, surface: 'code_mode', file_path: path });
-            const el = document.querySelector(`[data-code-path="${CSS.escape(path)}"] pre code`);
-            if (el) navigator.clipboard.writeText(el.textContent ?? '');
-          }}
-        >Copy</button>
-      </div>
-      <div data-code-path={path} dangerouslySetInnerHTML={{ __html: content }} />
-    </div>
-  );
+  return <div className="cockpit-code-pane" dangerouslySetInnerHTML={{ __html: content }} />;
 }
 
 export function CodeMode({ entryTitle, codeAssetPaths, backendAssetPaths, codeFiles, promptFiles, capability }: CodeModeProps) {
@@ -206,24 +181,20 @@ export function CodeMode({ entryTitle, codeAssetPaths, backendAssetPaths, codeFi
             </TabsList>
 
             {openPaths.filter((p) => !isPromptPath(p)).map((path) => (
-              <TabsContent key={path} value={path} className="flex-1 overflow-auto py-6 px-4 md:px-8">
-                <div className="cockpit-prose cockpit-prose--code">
-                  <CodeFileContent path={path} content={codeFiles[path]} capability={capability} />
-                </div>
+              <TabsContent key={path} value={path} className="flex-1 overflow-auto">
+                <CodeFileContent path={path} content={codeFiles[path]} />
               </TabsContent>
             ))}
 
             {openPaths.filter(isPromptPath).map((path) => {
               const content = promptFiles[path];
               return (
-                <TabsContent key={path} value={path} className="flex-1 overflow-auto py-6 px-4 md:px-8">
-                  <div className="cockpit-prose cockpit-prose--code">
-                    {content ? (
-                      <pre className="font-mono text-sm whitespace-pre-wrap">{content}</pre>
-                    ) : (
-                      <p className="text-sm text-[var(--ds-text-muted)]">No content for {getTabLabel(path)}</p>
-                    )}
-                  </div>
+                <TabsContent key={path} value={path} className="flex-1 overflow-auto">
+                  {content ? (
+                    <pre className="cockpit-code-pane cockpit-code-pane--plain">{content}</pre>
+                  ) : (
+                    <p className="cockpit-code-pane__empty">No content for {getTabLabel(path)}</p>
+                  )}
                 </TabsContent>
               );
             })}
diff --git a/apps/cockpit/src/components/code-mode/file-tree.tsx b/apps/cockpit/src/components/code-mode/file-tree.tsx
index 1b17fe2c..17f15293 100644
--- a/apps/cockpit/src/components/code-mode/file-tree.tsx
+++ b/apps/cockpit/src/components/code-mode/file-tree.tsx
@@ -89,7 +89,14 @@ function Node({ node, depth, folderId, activePath, collapsedFolders, onToggleFol
         className="cockpit-file-tree__folder"
         style={{ paddingLeft: `${0.5 + depth * 0.75}rem` }}
       >
-        <span className="cockpit-file-tree__caret" aria-hidden="true">{isCollapsed ? '▸' : '▾'}</span>
+        <span
+          className={`cockpit-file-tree__caret${isCollapsed ? '' : ' cockpit-file-tree__caret--open'}`}
+          aria-hidden="true"
+        >
+          <svg width="10" height="10" viewBox="0 0 10 10" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round" strokeLinejoin="round">
+            <path d="M3.5 2.5 6.5 5 3.5 7.5" />
+          </svg>
+        </span>
         <span className="cockpit-file-tree__label">{folder.label}</span>
       </button>
       {!isCollapsed ? (
diff --git a/apps/cockpit/src/components/sidebar/navigation-groups.tsx b/apps/cockpit/src/components/sidebar/navigation-groups.tsx
index a682d0ff..dd132c3e 100644
--- a/apps/cockpit/src/components/sidebar/navigation-groups.tsx
+++ b/apps/cockpit/src/components/sidebar/navigation-groups.tsx
@@ -50,13 +50,13 @@ function ProductGroup({
         }}>
           {label}
         </span>
-        <span style={{
-          color: 'var(--ds-text-muted)',
-          fontSize: 10,
-          transition: 'transform 0.2s',
-          transform: open ? 'rotate(0)' : 'rotate(-90deg)',
-        }}>
-          ▾
+        <span
+          className={`cockpit-nav-caret${open ? ' cockpit-nav-caret--open' : ''}`}
+          aria-hidden="true"
+        >
+          <svg width="10" height="10" viewBox="0 0 10 10" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round" strokeLinejoin="round">
+            <path d="M3.5 2.5 6.5 5 3.5 7.5" />
+          </svg>
         </span>
       </button>
 
@@ -85,18 +85,7 @@ function ProductGroup({
                     });
                   }}
                   aria-current={isActive ? 'page' : undefined}
-                  className={isActive ? 'border-l-2 border-[var(--ds-accent)]' : 'border-l-2 border-transparent'}
-                  style={{
-                    display: 'block',
-                    padding: '5px 16px 5px 14px',
-                    margin: '0 8px',
-                    borderRadius: 6,
-                    fontSize: '0.825rem',
-                    color: isActive ? 'var(--ds-accent)' : 'var(--ds-text-secondary)',
-                    background: isActive ? 'var(--ds-accent-surface)' : 'transparent',
-                    textDecoration: 'none',
-                    transition: 'all 0.15s',
-                  }}
+                  className="cockpit-nav-item"
                 >
                   {stripProductPrefix(entry.title)}
                 </a>
diff --git a/apps/cockpit/src/lib/content-bundle.ts b/apps/cockpit/src/lib/content-bundle.ts
index d9fbee10..a9ecc89f 100644
--- a/apps/cockpit/src/lib/content-bundle.ts
+++ b/apps/cockpit/src/lib/content-bundle.ts
@@ -101,7 +101,7 @@ async function highlightCode(
   try {
     return await codeToHtml(source, {
       lang: detectLang(filePath),
-      theme: 'tokyo-night',
+      themes: { light: 'github-light', dark: 'tokyo-night' },
     });
   } catch {
     return `<pre><code>${escapeHtml(source)}</code></pre>`;
diff --git a/apps/cockpit/src/lib/render-markdown.ts b/apps/cockpit/src/lib/render-markdown.ts
index 0ac11cfe..e9718d2f 100644
--- a/apps/cockpit/src/lib/render-markdown.ts
+++ b/apps/cockpit/src/lib/render-markdown.ts
@@ -112,7 +112,7 @@ async function parseStepContent(
     const codeToHighlight = filename ? cleanedCode : block.code;
     let highlighted: string;
     try {
-      highlighted = await codeToHtml(codeToHighlight, { lang: block.lang, theme: 'tokyo-night' });
+      highlighted = await codeToHtml(codeToHighlight, { lang: block.lang, themes: { light: 'github-light', dark: 'tokyo-night' } });
     } catch {
       const escaped = codeToHighlight.replace(/</g, '&lt;').replace(/>/g, '&gt;');
       highlighted = `<pre><code>${escaped}</code></pre>`;
@@ -169,7 +169,7 @@ export async function renderMarkdown(source: string): Promise<RenderedMarkdown>
     const codeToHighlight = filename ? cleanedCode : block.code;
     let highlighted: string;
     try {
-      highlighted = await codeToHtml(codeToHighlight, { lang: block.lang, theme: 'tokyo-night' });
+      highlighted = await codeToHtml(codeToHighlight, { lang: block.lang, themes: { light: 'github-light', dark: 'tokyo-night' } });
     } catch {
       const escaped = codeToHighlight.replace(/</g, '&lt;').replace(/>/g, '&gt;');
       highlighted = `<pre><code>${escaped}</code></pre>`;