Started addig the side panel

frontend/src/layout/navigation-3000/Navigation.tsx

@@ -12,6 +12,7 @@ import { NotebookPopover } from 'scenes/notebooks/Notebook/NotebookPopover'
 import { Scene, SceneConfig } from 'scenes/sceneTypes'
 import { FlaggedFeature } from 'lib/components/FlaggedFeature'
 import { FEATURE_FLAGS } from 'lib/constants'
+import { SidePanel } from './sidepanel/SidePanel'
 
 export function Navigation({
     children,
@@ -47,6 +48,7 @@ export function Navigation({
                     {children}
                 </div>
             </main>
+            <SidePanel />
             <CommandPalette />
         </div>
     )

frontend/src/layout/navigation-3000/sidepanel/SidePanel.scss

@@ -0,0 +1,24 @@
+.SidePanel3000 {
+    flex: 0 0 3rem;
+    border-left: 1px solid transparent; // This is just for sizing, the visible border is on the content
+    box-sizing: content-box;
+    z-index: var(--z-main-nav);
+
+    .LemonButton {
+        min-height: 2.25rem !important; // Reduce minimum height
+    }
+}
+
+.SidePanel3000__content {
+    position: fixed;
+    top: 0;
+    right: 0;
+    display: flex;
+    flex-direction: column;
+    justify-content: space-between;
+    height: 100vh;
+    width: 3rem;
+    border-left-width: 1px;
+    background: var(--accent-3000);
+    overflow-y: auto;
+}

frontend/src/layout/navigation-3000/sidepanel/SidePanel.tsx

@@ -0,0 +1,19 @@
+import { LemonButton } from '@posthog/lemon-ui'
+import './SidePanel.scss'
+import { IconComment, IconNotebook } from 'lib/lemon-ui/icons'
+
+export function SidePanel(): JSX.Element {
+    return (
+        <nav className="SidePanel3000">
+            <div className="SidePanel3000__content">
+                <div className="SidePanel3000__top">
+                    <div className="rotate-90 flex items-center gap-2 px-2">
+                        <LemonButton icon={<IconNotebook className="rotate-270" />}>Notebooks</LemonButton>
+                        <LemonButton icon={<IconComment className="rotate-270" />}>Feedback</LemonButton>
+                    </div>
+                </div>
+                <div className="SidePanel3000__bottom"></div>
+            </div>
+        </nav>
+    )
+}