Add Nebula guide sidebar and navigation

Introduce a new Xbox-style guide (rail + expanded panel) to the shell: adds guideSidebar component, data model, styles, and panel overlay (src/core/guideSidebar.js, src/core/sidebarData.js, src/styles/guide.css, src/views/overlays/guidePanel.*). Integrates the guide into the app lifecycle and routing (main.js): mounts the guide, remaps focus roots, adds guide open/close behavior, and registers placeholder views for store/mods. Input and navigation updated to support a dedicated "guide" action and region (src/core/input.js, src/core/nav.js) so focus movement and acceptance work inside the guide. index.html updated to mount the guide and include templates/styles; base/component CSS adjusted to accommodate the new mount and focus states. Misc: adds a placeholder view and wiring for guide panel overlays and tweaks power menu handling to cooperate with the guide.

src/core/guideSidebar.js

@@ -0,0 +1,478 @@
+import {
+  NAVIGABLE_VIEWS,
+  PRIMARY_NAV,
+  QUICK_ACTIONS,
+  RECENT_ITEMS,
+  SOURCE_LABELS,
+} from "./sidebarData.js";
+
+const escapeHtml = (value) =>
+  String(value)
+    .replaceAll("&", "&")
+    .replaceAll("<", "&lt;")
+    .replaceAll(">", "&gt;")
+    .replaceAll('"', "&quot;");
+
+const initialsFor = (name) =>
+  name
+    .split(/\s+/)
+    .filter(Boolean)
+    .slice(0, 2)
+    .map((part) => part[0]?.toUpperCase())
+    .join("") || "NU";
+
+const renderRailNav = () =>
+  PRIMARY_NAV.map(
+    (item, index) => `
+    <li
+      class="guide-rail-item focusable"
+      role="listitem"
+      data-sidebar-nav="${item.id}"
+      data-target="${item.target}"
+      data-nav-region="sidebar"
+      data-focusable="true"
+      data-row="${index}"
+      data-col="-1"
+      data-focus-key="rail-${item.id}"
+      aria-label="${escapeHtml(item.label)}"
+    >
+      <span class="guide-rail-icon" aria-hidden="true">${item.icon}</span>
+    </li>
+  `,
+  ).join("");
+
+const renderPanelNav = () =>
+  PRIMARY_NAV.map(
+    (item, index) => `
+    <li
+      class="guide-nav-item focusable"
+      role="listitem"
+      data-sidebar-nav="${item.id}"
+      data-target="${item.target}"
+      data-nav-region="guide"
+      data-focusable="true"
+      data-row="${index}"
+      data-col="0"
+      data-focus-key="guide-nav-${item.id}"
+    >
+      <span class="guide-nav-icon" aria-hidden="true">${item.icon}</span>
+      <span class="guide-nav-label">${escapeHtml(item.label)}</span>
+    </li>
+  `,
+  ).join("");
+
+const renderQuickActions = () =>
+  QUICK_ACTIONS.map(
+    (item, index) => `
+    <button
+      type="button"
+      class="guide-quick-item focusable"
+      data-guide-action="${item.id}"
+      data-panel="${item.panel ?? ""}"
+      data-action-type="${item.action ?? "panel"}"
+      data-nav-region="guide"
+      data-focusable="true"
+      data-row="${PRIMARY_NAV.length + 1 + Math.floor(index / 2)}"
+      data-col="${index % 2}"
+      data-focus-key="guide-quick-${item.id}"
+      aria-label="${escapeHtml(item.label)}"
+    >
+      <span class="guide-quick-icon" aria-hidden="true">${item.icon}</span>
+      <span class="guide-quick-label">${escapeHtml(item.label)}</span>
+    </button>
+  `,
+  ).join("");
+
+const renderRecentItems = () => {
+  if (!RECENT_ITEMS.length) {
+    return `
+      <div class="guide-recent-empty" aria-live="polite">
+        <span class="guide-recent-empty-icon" aria-hidden="true">⊟</span>
+        <p class="guide-recent-empty-title">No recent activity</p>
+        <p class="guide-recent-empty-copy">Launch a game from your library to see it here.</p>
+      </div>
+    `;
+  }
+
+  return RECENT_ITEMS.map(
+    (item, index) => `
+    <button
+      type="button"
+      class="guide-recent-item focusable"
+      data-recent-id="${item.id}"
+      data-nav-region="guide"
+      data-focusable="true"
+      data-row="${PRIMARY_NAV.length + 4 + index}"
+      data-col="0"
+      data-focus-key="guide-recent-${item.id}"
+      aria-label="${escapeHtml(item.title)}, ${escapeHtml(SOURCE_LABELS[item.source] ?? item.source)}"
+    >
+      <span class="guide-recent-cover" style="--recent-accent: ${item.accent}" aria-hidden="true"></span>
+      <span class="guide-recent-meta">
+        <span class="guide-recent-title">${escapeHtml(item.title)}</span>
+        <span class="guide-recent-sub">
+          <span class="guide-source-badge" data-source="${item.source}">${escapeHtml(SOURCE_LABELS[item.source] ?? item.source)}</span>
+          <span class="guide-recent-time">${escapeHtml(item.lastPlayed)}</span>
+        </span>
+      </span>
+    </button>
+  `,
+  ).join("");
+};
+
+const GUIDE_MARKUP = `
+<aside class="guide-shell" id="guide-sidebar" aria-label="Nebula guide navigation">
+  <div class="guide-rail" id="guide-rail" data-guide-rail>
+    <button
+      type="button"
+      class="guide-rail-brand focusable"
+      data-nav-region="sidebar"
+      data-focusable="true"
+      data-row="-1"
+      data-col="-1"
+      data-focus-key="rail-brand"
+      data-guide-action="toggle"
+      aria-label="Open Nebula guide"
+      aria-expanded="false"
+      aria-controls="guide-panel"
+    >
+      <span class="guide-brand-mark" aria-hidden="true">✦</span>
+    </button>
+
+    <ul class="guide-rail-nav" role="list">
+      ${renderRailNav()}
+    </ul>
+
+    <div class="guide-rail-footer">
+      <button
+        type="button"
+        class="guide-rail-expand focusable"
+        data-guide-action="toggle"
+        data-nav-region="sidebar"
+        data-focusable="true"
+        data-row="99"
+        data-col="-1"
+        data-focus-key="rail-expand"
+        aria-label="Open guide panel"
+      >
+        <span class="guide-rail-expand-icon" aria-hidden="true">☰</span>
+      </button>
+      <button
+        type="button"
+        class="guide-rail-profile focusable"
+        data-guide-action="profile"
+        data-nav-region="sidebar"
+        data-focusable="true"
+        data-row="100"
+        data-col="-1"
+        data-focus-key="rail-profile"
+        aria-label="Profile"
+      >
+        <span class="guide-rail-avatar" data-profile-avatar aria-hidden="true"></span>
+      </button>
+    </div>
+  </div>
+
+  <div
+    class="guide-panel"
+    id="guide-panel"
+    role="dialog"
+    aria-modal="true"
+    aria-label="Nebula guide"
+    aria-hidden="true"
+    hidden
+  >
+    <div class="guide-panel-inner" data-guide-focus-root>
+      <header class="guide-header">
+        <div class="guide-profile">
+          <span class="guide-profile-avatar" data-profile-avatar aria-hidden="true"></span>
+          <div class="guide-profile-copy">
+            <p class="guide-profile-name" data-profile-name>Nebula User</p>
+            <p class="guide-profile-status">
+              <span class="guide-status-dot" aria-hidden="true"></span>
+              <span data-profile-status>Online</span>
+            </p>
+          </div>
+        </div>
+        <div class="guide-header-meta">
+          <p class="guide-header-time" data-clock>--:--</p>
+          <p class="guide-header-date" data-date></p>
+          <div class="guide-header-indicators" aria-label="System status">
+            <span class="guide-indicator" title="Network connected" aria-hidden="true">◉</span>
+            <span class="guide-indicator" title="Controller ready" aria-hidden="true">🎮</span>
+          </div>
+        </div>
+        <p class="guide-header-brand">
+          <span class="guide-header-brand-mark" aria-hidden="true">✦</span>
+          Nebula OS
+        </p>
+      </header>
+
+      <hr class="guide-divider" />
+
+      <section class="guide-section" aria-labelledby="guide-nav-heading">
+        <h2 class="guide-section-title" id="guide-nav-heading">Navigate</h2>
+        <ul class="guide-nav-list" role="list">
+          ${renderPanelNav()}
+        </ul>
+      </section>
+
+      <hr class="guide-divider" />
+
+      <section class="guide-section" aria-labelledby="guide-quick-heading">
+        <h2 class="guide-section-title" id="guide-quick-heading">Quick actions</h2>
+        <div class="guide-quick-grid">
+          ${renderQuickActions()}
+        </div>
+      </section>
+
+      <hr class="guide-divider" />
+
+      <section class="guide-section guide-section-recent" aria-labelledby="guide-recent-heading">
+        <h2 class="guide-section-title" id="guide-recent-heading">Recent</h2>
+        <div class="guide-recent-list">
+          ${renderRecentItems()}
+        </div>
+      </section>
+
+      <footer class="guide-footer">
+        <button
+          type="button"
+          class="guide-footer-btn focusable"
+          data-guide-action="profile"
+          data-nav-region="guide"
+          data-focusable="true"
+          data-row="200"
+          data-col="0"
+          data-focus-key="guide-footer-profile"
+          aria-label="Profile"
+        >
+          <span class="guide-footer-avatar" data-profile-avatar aria-hidden="true"></span>
+          <span>Profile</span>
+        </button>
+        <button
+          type="button"
+          class="guide-footer-btn focusable"
+          data-target="settings"
+          data-nav-region="guide"
+          data-focusable="true"
+          data-row="200"
+          data-col="1"
+          data-focus-key="guide-footer-settings"
+        >
+          <span aria-hidden="true">⚙</span>
+          <span>Settings</span>
+        </button>
+        <button
+          type="button"
+          class="guide-footer-btn focusable"
+          data-guide-action="power"
+          data-nav-region="guide"
+          data-focusable="true"
+          data-row="200"
+          data-col="2"
+          data-focus-key="guide-footer-power"
+        >
+          <span aria-hidden="true">⏻</span>
+          <span>Power</span>
+        </button>
+        <p class="guide-version" data-guide-version>NebulaOS · Shell Preview</p>
+      </footer>
+    </div>
+  </div>
+</aside>
+`;
+
+export const createGuideSidebar = ({
+  state,
+  renderView,
+  openPowerMenu,
+  openGuidePanel,
+  onGuideChange,
+}) => {
+  let shellEl = null;
+  let backdropEl = null;
+  let panelEl = null;
+  let expanded = false;
+  let lastFocusedKey = null;
+
+  const syncProfile = () => {
+    if (!shellEl) return;
+    const name = state.profileName || "Nebula User";
+    const initials = initialsFor(name);
+    shellEl.querySelectorAll("[data-profile-name]").forEach((el) => {
+      el.textContent = name;
+    });
+    shellEl.querySelectorAll("[data-profile-avatar], .guide-rail-avatar, .guide-footer-avatar").forEach((el) => {
+      el.textContent = initials;
+      el.setAttribute("aria-label", name);
+    });
+  };
+
+  const setExpanded = (next) => {
+    expanded = next;
+    document.body.classList.toggle("guide-expanded", expanded);
+
+    if (panelEl) {
+      panelEl.hidden = !expanded;
+      panelEl.setAttribute("aria-hidden", expanded ? "false" : "true");
+    }
+
+    if (backdropEl) {
+      backdropEl.hidden = !expanded;
+    }
+
+    shellEl?.querySelectorAll("[data-guide-action='toggle'], .guide-rail-brand").forEach((btn) => {
+      btn.setAttribute("aria-expanded", expanded ? "true" : "false");
+    });
+
+    onGuideChange?.({ expanded });
+  };
+
+  const open = () => {
+    if (expanded) return;
+    const focused = document.querySelector(".is-focused");
+    lastFocusedKey = focused?.dataset?.focusKey ?? null;
+    setExpanded(true);
+    window.dispatchEvent(new CustomEvent("nebula-guide-open"));
+  };
+
+  const close = () => {
+    if (!expanded) return;
+    setExpanded(false);
+    window.dispatchEvent(
+      new CustomEvent("nebula-guide-close", {
+        detail: { focusKey: lastFocusedKey },
+      }),
+    );
+  };
+
+  const toggle = () => {
+    if (expanded) {
+      close();
+    } else {
+      open();
+    }
+  };
+
+  const navigateTo = (target) => {
+    if (!target || !NAVIGABLE_VIEWS.has(target)) {
+      return false;
+    }
+    close();
+    renderView(target);
+    return true;
+  };
+
+  const handleGuideAction = (element) => {
+    const action = element?.dataset?.guideAction;
+    if (action === "toggle") {
+      toggle();
+      return true;
+    }
+    if (action === "power") {
+      close();
+      openPowerMenu?.();
+      return true;
+    }
+    if (action === "profile") {
+      console.log("[Guide] Profile panel (placeholder)");
+      return true;
+    }
+
+    const panel = element?.dataset?.panel;
+    if (panel) {
+      close();
+      openGuidePanel?.(panel);
+      return true;
+    }
+
+    return false;
+  };
+
+  const handleAccept = (focused) => {
+    if (!focused) return false;
+
+    const target = focused.dataset.target;
+    if (target && focused.dataset.navRegion) {
+      return navigateTo(target);
+    }
+
+    if (focused.dataset.recentId) {
+      console.log(`[Guide] Recent item: ${focused.dataset.recentId}`);
+      return true;
+    }
+
+    return handleGuideAction(focused);
+  };
+
+  const updateActiveView = (viewId) => {
+    if (!shellEl) return;
+    shellEl.querySelectorAll("[data-sidebar-nav]").forEach((item) => {
+      const matches = item.dataset.sidebarNav === viewId;
+      item.classList.toggle("is-active", matches);
+      if (matches) {
+        item.setAttribute("aria-current", "page");
+      } else {
+        item.removeAttribute("aria-current");
+      }
+    });
+  };
+
+  const bindPointer = () => {
+    shellEl?.addEventListener("click", (event) => {
+      const item = event.target.closest("[data-focusable='true']");
+      if (!item || item.dataset.disabled === "true") return;
+
+      if (item.dataset.guideAction === "toggle" && !expanded) {
+        open();
+        return;
+      }
+
+      if (item.dataset.target || item.dataset.guideAction || item.dataset.recentId || item.dataset.panel) {
+        handleAccept(item);
+        window.dispatchEvent(
+          new CustomEvent("nebula-navigation-refresh", {
+            detail: { focusKey: item.dataset.focusKey },
+          }),
+        );
+      }
+    });
+
+    backdropEl?.addEventListener("click", () => close());
+  };
+
+  const mount = ({ shellRoot, backdropRoot }) => {
+    shellRoot.innerHTML = GUIDE_MARKUP;
+    shellEl = shellRoot.querySelector("#guide-sidebar") ?? shellRoot;
+    panelEl = shellRoot.querySelector("#guide-panel");
+    backdropEl = backdropRoot;
+    syncProfile();
+    bindPointer();
+    setExpanded(false);
+  };
+
+  const getFocusRoots = () => {
+    if (!shellEl || document.body.classList.contains("body-no-sidebar")) {
+      return [];
+    }
+    if (expanded) {
+      const root = shellEl.querySelector("[data-guide-focus-root]");
+      return root ? [root] : [];
+    }
+    const rail = shellEl.querySelector("[data-guide-rail]");
+    return rail ? [rail] : [];
+  };
+
+  return {
+    mount,
+    open,
+    close,
+    toggle,
+    isExpanded: () => expanded,
+    updateActiveView,
+    getFocusRoots,
+    handleAccept,
+    syncProfile,
+  };
+};

src/core/input.js

@@ -9,6 +9,7 @@ const KEYBOARD_MAP = {
   KeyE: "r1",
   KeyZ: "l2",
   KeyC: "r2",
+  KeyG: "guide",
   Enter: "accept",
   Escape: "back",
   Backspace: "back",
@@ -104,6 +105,9 @@ export const createInputManager = ({ onAction, actions }) => {
             { source: "keyboard", control: "KeyM" },
             { source: "gamepad", control: "start" },
           ],
+          guide: [
+            { source: "keyboard", control: "KeyG" },
+          ],
           clear: [
             { source: "keyboard", control: "KeyX" },
             { source: "gamepad", control: "x" },
@@ -140,7 +144,9 @@ export const createInputManager = ({ onAction, actions }) => {
   };
 
   const onKeyDown = (event) => {
-    const action = KEYBOARD_MAP[event.code] ?? (event.code === "KeyM" ? "menu" : null);
+    const action =
+      KEYBOARD_MAP[event.code] ??
+      (event.code === "KeyM" ? "menu" : event.code === "KeyG" ? "guide" : null);
     if (!action) {
       return;
     }

src/core/nav.js

@@ -221,18 +221,18 @@ export const createNavigationManager = () => {
       if (idx >= 0) return idx;
     }
 
-    const contentIdx = focusables.findIndex((f) => f.region !== "sidebar");
+    const contentIdx = focusables.findIndex((f) => f.region !== "sidebar" && f.region !== "guide");
     return contentIdx >= 0 ? contentIdx : 0;
   };
 
   const findContentDefaultIndex = () => {
     if (contract?.defaultFocus) {
       const idx = focusables.findIndex((f) => f.element === contract.defaultFocus);
-      if (idx >= 0 && focusables[idx].region !== "sidebar") {
+      if (idx >= 0 && focusables[idx].region !== "sidebar" && focusables[idx].region !== "guide") {
         return idx;
       }
     }
-    return focusables.findIndex((f) => f.region !== "sidebar");
+    return focusables.findIndex((f) => f.region !== "sidebar" && f.region !== "guide");
   };
 
   const findSidebarTargetIndex = () => {
@@ -243,28 +243,30 @@ export const createNavigationManager = () => {
     return focusables.findIndex((f) => f.region === "sidebar");
   };
 
-  const findNextSidebarIndex = (direction) => {
+  const findNextRegionIndex = (direction, region) => {
-    const sidebarItems = focusables
+    const regionItems = focusables
       .map((focusable, index) => ({ focusable, index }))
-      .filter(({ focusable }) => focusable.region === "sidebar");
+      .filter(({ focusable }) => focusable.region === region);
 
-    if (!sidebarItems.length) return null;
+    if (!regionItems.length) return null;
 
-    // Sort sidebar items by physical Y position so the order matches what the
+    regionItems.sort((a, b) => {
-    // user sees, regardless of how the markup was authored.
-    sidebarItems.sort((a, b) => {
       const ra = a.focusable.element.getBoundingClientRect();
       const rb = b.focusable.element.getBoundingClientRect();
       return ra.top - rb.top;
     });
 
-    const currentSlot = sidebarItems.findIndex(({ index }) => index === focusedIndex);
+    const currentSlot = regionItems.findIndex(({ index }) => index === focusedIndex);
     if (currentSlot < 0) return null;
 
     const nextSlot = direction === "up" ? currentSlot - 1 : currentSlot + 1;
-    return sidebarItems[nextSlot]?.index ?? null;
+    return regionItems[nextSlot]?.index ?? null;
   };
 
+  const findNextSidebarIndex = (direction) => findNextRegionIndex(direction, "sidebar");
+
+  const findNextGuideIndex = (direction) => findNextRegionIndex(direction, "guide");
+
   const findBestContentSpatialIndex = (direction) => {
     const source = focusables[focusedIndex];
     if (!source) return -1;
@@ -279,7 +281,7 @@ export const createNavigationManager = () => {
 
     focusables.forEach((candidate, idx) => {
       if (idx === focusedIndex) return;
-      if (candidate.region === "sidebar") return;
+      if (candidate.region === "sidebar" || candidate.region === "guide") return;
 
       const targetRect = getRect(candidate.element);
       const score = scoreCandidate(sourceRect, targetRect, direction, anchorPerpCenter);
@@ -354,7 +356,37 @@ export const createNavigationManager = () => {
     const source = focusables[focusedIndex];
     const sourceRect = getRect(source.element);
 
-    // -- Sidebar region ----------------------------------------------------
+    // -- Guide panel (expanded shell navigation) ---------------------------
+    if (source.region === "guide") {
+      if (direction === "up" || direction === "down") {
+        const next = findNextGuideIndex(direction);
+        if (next !== null) applyFocus(next);
+        return;
+      }
+      if (direction === "left" || direction === "right") {
+        const lateral = focusables
+          .map((focusable, index) => ({ focusable, index }))
+          .filter(({ focusable }) => focusable.region === "guide")
+          .filter(({ focusable }) => {
+            const row = Number(focusable.element.dataset.row ?? 0);
+            return row === Number(source.element.dataset.row ?? 0);
+          })
+          .sort((a, b) => {
+            const ra = a.focusable.element.getBoundingClientRect();
+            const rb = b.focusable.element.getBoundingClientRect();
+            return ra.left - rb.left;
+          });
+
+        const slot = lateral.findIndex(({ index }) => index === focusedIndex);
+        if (slot < 0) return;
+        const nextSlot = direction === "left" ? slot - 1 : slot + 1;
+        const next = lateral[nextSlot]?.index;
+        if (next !== undefined) applyFocus(next);
+      }
+      return;
+    }
+
+    // -- Collapsed sidebar rail --------------------------------------------
     if (source.region === "sidebar") {
       if (direction === "up" || direction === "down") {
         const next = findNextSidebarIndex(direction);
@@ -369,7 +401,6 @@ export const createNavigationManager = () => {
         }
         return;
       }
-      // direction === "left" from sidebar: nothing further left.
       return;
     }
 

src/core/sidebarData.js

@@ -0,0 +1,58 @@
+/** Primary shell navigation (data-driven). */
+export const PRIMARY_NAV = [
+  { id: "home", label: "Home", icon: "⌂", target: "home" },
+  { id: "library", label: "Library", icon: "⊟", target: "library" },
+  { id: "store", label: "Store", icon: "⊞", target: "store" },
+  { id: "mods", label: "Mods", icon: "◇", target: "mods" },
+  { id: "settings", label: "Settings", icon: "⚙", target: "settings" },
+];
+
+/** Quick actions in the expanded guide. */
+export const QUICK_ACTIONS = [
+  { id: "search", label: "Search", icon: "⌕", panel: "search" },
+  { id: "notifications", label: "Notifications", icon: "🔔", panel: "notifications" },
+  { id: "downloads", label: "Downloads", icon: "↓", panel: "downloads" },
+  { id: "controller", label: "Controller Settings", icon: "🎮", panel: "controller" },
+  { id: "power", label: "Power Menu", icon: "⏻", action: "power" },
+];
+
+/** Mock recently played titles (replace with library bridge later). */
+export const RECENT_ITEMS = [
+  {
+    id: "recent-halo",
+    title: "Halo Infinite",
+    source: "steam",
+    lastPlayed: "2 hours ago",
+    accent: "#1e4a6e",
+  },
+  {
+    id: "recent-cyber",
+    title: "Cyberpunk 2077",
+    source: "gog",
+    lastPlayed: "Yesterday",
+    accent: "#5c1a3a",
+  },
+  {
+    id: "recent-fortnite",
+    title: "Fortnite",
+    source: "epic",
+    lastPlayed: "3 days ago",
+    accent: "#2a3a5c",
+  },
+  {
+    id: "recent-emulator",
+    title: "Nebula Arcade",
+    source: "local",
+    lastPlayed: "Last week",
+    accent: "#1a3c2e",
+  },
+];
+
+export const SOURCE_LABELS = {
+  steam: "Steam",
+  gog: "GOG",
+  epic: "Epic",
+  local: "Local",
+};
+
+export const NAVIGABLE_VIEWS = new Set(PRIMARY_NAV.map((item) => item.target));

src/index.html

@@ -5,6 +5,7 @@
     <link rel="stylesheet" href="/styles/theme.css" />
     <link rel="stylesheet" href="/styles/base.css" />
     <link rel="stylesheet" href="/styles/components.css" />
+    <link rel="stylesheet" href="/styles/guide.css" />
     <link rel="stylesheet" href="/views/lock/lock.css" />
     <link rel="stylesheet" href="/views/onboarding/userSetup.css" />
     <link rel="stylesheet" href="/views/home/home.css" />
@@ -12,6 +13,7 @@
     <link rel="stylesheet" href="/views/library/library.css" />
     <link rel="stylesheet" href="/views/overlays/powerMenu.css" />
     <link rel="stylesheet" href="/views/overlays/keyboard.css" />
+    <link rel="stylesheet" href="/views/overlays/guidePanel.css" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>Nebula Shell</title>
     <script type="module" src="/main.js" defer></script>
@@ -25,49 +27,15 @@
       <div class="nebula-layer vignette"></div>
     </div>
 
+    <div class="guide-backdrop" id="guide-backdrop" hidden aria-hidden="true"></div>
+
     <div class="app-layout">
+      <div id="guide-shell-root" class="guide-mount"></div>
 
-      <!-- Persistent left sidebar — hidden for lock/onboarding via JS class -->
-      <nav class="sidebar" id="sidebar" aria-label="Main navigation">
-        <div class="sidebar-logo">
-          <span class="sidebar-logo-icon" aria-hidden="true">✦</span>
-          <span class="sidebar-logo-text">Nebula OS</span>
-        </div>
-
-        <ul class="sidebar-nav" role="list">
-          <li class="sidebar-nav-item is-active focusable" data-sidebar-nav="home" data-target="home" data-nav-region="sidebar" data-focusable="true" data-row="0" data-col="-1" data-focus-key="sidebar-home" role="listitem" aria-current="page">
-            <span class="sidebar-nav-icon" aria-hidden="true">⌂</span>
-            <span class="sidebar-nav-label">Home</span>
-          </li>
-          <li class="sidebar-nav-item focusable" data-sidebar-nav="library" data-target="library" data-nav-region="sidebar" data-focusable="true" data-row="1" data-col="-1" data-focus-key="sidebar-library" role="listitem">
-            <span class="sidebar-nav-icon" aria-hidden="true">⊟</span>
-            <span class="sidebar-nav-label">Library</span>
-          </li>
-          <li class="sidebar-nav-item focusable" data-sidebar-nav="store" data-nav-region="sidebar" data-focusable="true" data-row="2" data-col="-1" data-focus-key="sidebar-store" data-disabled="true" role="listitem" aria-disabled="true">
-            <span class="sidebar-nav-icon" aria-hidden="true">⊞</span>
-            <span class="sidebar-nav-label">Store</span>
-          </li>
-          <li class="sidebar-nav-item focusable" data-sidebar-nav="mods" data-nav-region="sidebar" data-focusable="true" data-row="3" data-col="-1" data-focus-key="sidebar-mods" data-disabled="true" role="listitem" aria-disabled="true">
-            <span class="sidebar-nav-icon" aria-hidden="true">◇</span>
-            <span class="sidebar-nav-label">Mods</span>
-          </li>
-          <li class="sidebar-nav-item focusable" data-sidebar-nav="appstore" data-nav-region="sidebar" data-focusable="true" data-row="4" data-col="-1" data-focus-key="sidebar-appstore" data-disabled="true" role="listitem" aria-disabled="true">
-            <span class="sidebar-nav-icon" aria-hidden="true">▣</span>
-            <span class="sidebar-nav-label">Appstore</span>
-          </li>
-        </ul>
-
-        <div class="sidebar-user">
-          <div class="sidebar-user-avatar" aria-hidden="true"></div>
-        </div>
-      </nav>
-
-      <!-- Main content area -->
       <div class="app-main-area">
         <main id="app" class="app-shell"></main>
         <footer class="app-footer" id="app-footer"></footer>
       </div>
-
     </div>
 
     <div id="overlay-root"></div>
@@ -77,14 +45,29 @@
       <div class="hint-row">
         <span class="hint"><span data-glyph="accept"></span> Select</span>
         <span class="hint"><span data-glyph="back"></span> Back</span>
-        <span class="hint"><span data-glyph="menu"></span> Menu</span>
+        <span class="hint"><span data-glyph="menu"></span> Guide</span>
+      </div>
+    </template>
+
+    <template id="guide-hints-template">
+      <div class="hint-row">
+        <span class="hint"><span data-glyph="accept"></span> Select</span>
+        <span class="hint"><span data-glyph="back"></span> Close</span>
+        <span class="hint"><span data-glyph="menu"></span> Close Guide</span>
+      </div>
+    </template>
+
+    <template id="guide-panel-hints-template">
+      <div class="hint-row">
+        <span class="hint"><span data-glyph="accept"></span> Close</span>
+        <span class="hint"><span data-glyph="back"></span> Close</span>
       </div>
     </template>
 
     <template id="minimal-hints-template">
       <div class="hint-row">
-        <span class="hint"><span data-glyph="accept"></span> Open</span>
+        <span class="hint"><span data-glyph="accept"></span> Confirm</span>
-        <span class="hint"><span data-glyph="menu"></span> Power Menu</span>
+        <span class="hint"><span data-glyph="back"></span> Cancel</span>
       </div>
     </template>
 

src/main.js

@@ -1,3 +1,5 @@
+import { createGuideSidebar } from "./core/guideSidebar.js";
+import { NAVIGABLE_VIEWS } from "./core/sidebarData.js";
 import { createInputManager } from "./core/input.js";
 import { createNavigationManager } from "./core/nav.js";
 import { createRouter } from "./core/router.js";
@@ -6,29 +8,76 @@ import { createHomeView } from "./views/home/home.js";
 import { createLibraryView } from "./views/library/library.js";
 import { createLockView } from "./views/lock/lock.js";
 import { createUserSetupView } from "./views/onboarding/userSetup.js";
+import { createGuidePanelOverlay } from "./views/overlays/guidePanel.js";
 import { createKeyboardOverlay } from "./views/overlays/keyboard.js";
 import { createPowerMenuOverlay } from "./views/overlays/powerMenu.js";
+import { createPlaceholderView } from "./views/placeholder/placeholder.js";
 import { createSettingsView } from "./views/settings/settings.js";
 
 const appRoot = document.querySelector("#app");
 const overlayRoot = document.querySelector("#overlay-root");
 const keyboardRoot = document.querySelector("#keyboard-root");
 const footer = document.querySelector("#app-footer");
+const guideShellRoot = document.querySelector("#guide-shell-root");
+const guideBackdrop = document.querySelector("#guide-backdrop");
 
-// Views that should hide the sidebar (full-screen flows)
 const SIDEBAR_HIDDEN_VIEWS = new Set(["lock", "user-setup"]);
 
-// Views that can be opened from the persistent sidebar.
-const SIDEBAR_NAV_VIEWS = new Set(["home", "library", "settings"]);
-
 const state = createAppState();
 const nav = createNavigationManager();
 const router = createRouter(appRoot);
-const powerMenu = createPowerMenuOverlay({ mountRoot: overlayRoot, state });
+const guidePanels = createGuidePanelOverlay({ mountRoot: overlayRoot });
+const powerMenu = createPowerMenuOverlay({ mountRoot: overlayRoot });
 const keyboard = createKeyboardOverlay({ mountRoot: keyboardRoot });
 
 let currentViewContract = null;
 
+const remountNavigation = (options = {}) => {
+  if (!currentViewContract) return;
+
+  currentViewContract = {
+    ...currentViewContract,
+    extraFocusRoots: SIDEBAR_HIDDEN_VIEWS.has(state.activeView)
+      ? []
+      : guideSidebar.getFocusRoots(),
+    defaultFocus: options.defaultFocus ?? currentViewContract.defaultFocus,
+  };
+
+  nav.mount(currentViewContract);
+
+  if (options.focusKey) {
+    const target = document.querySelector(`[data-focus-key="${CSS.escape(options.focusKey)}"]`);
+    if (target) {
+      currentViewContract.defaultFocus = target;
+      nav.mount(currentViewContract);
+    }
+  }
+};
+
+const guideSidebar = createGuideSidebar({
+  state,
+  renderView,
+  openPowerMenu,
+  openGuidePanel: (panelId) => {
+    guidePanels.open(panelId, {
+      onClose: () => remountNavigation(),
+    });
+    setFooterHints("#guide-panel-hints-template", state.glyphs);
+  },
+  onGuideChange: ({ expanded }) => {
+    if (expanded) {
+      const active = document.querySelector(
+        "#guide-panel [data-sidebar-nav].is-active, #guide-panel .guide-nav-item",
+      );
+      remountNavigation({ defaultFocus: active ?? undefined });
+      setFooterHints("#guide-hints-template", state.glyphs);
+      return;
+    }
+    remountNavigation();
+    setFooterHints(currentViewContract?.hintsTemplate ?? "#global-hints-template", state.glyphs);
+  },
+});
+
 const emitUiHook = (type, payload = {}) => {
   window.dispatchEvent(
     new CustomEvent("nebula-ui-hook", {
@@ -70,35 +119,21 @@ const updateClockLabels = () => {
   });
 };
 
-/**
- * Update the persistent left sidebar to reflect the active view.
- * Hides the sidebar entirely for lock/onboarding screens.
- */
 const updateSidebar = (viewId) => {
   const body = document.body;
-  const sidebar = document.querySelector("#sidebar");
 
   if (SIDEBAR_HIDDEN_VIEWS.has(viewId)) {
     body.classList.add("body-no-sidebar");
+    guideSidebar.close();
     return;
   }
 
   body.classList.remove("body-no-sidebar");
-
+  guideSidebar.updateActiveView(viewId);
-  if (!sidebar) return;
+  guideSidebar.syncProfile();
-
-  sidebar.querySelectorAll("[data-sidebar-nav]").forEach((item) => {
-    const matches = item.dataset.sidebarNav === viewId;
-    item.classList.toggle("is-active", matches);
-    if (matches) {
-      item.setAttribute("aria-current", "page");
-    } else {
-      item.removeAttribute("aria-current");
-    }
-  });
 };
 
-const renderView = (viewId) => {
+function renderView(viewId) {
   const contract = router.navigate(viewId);
   if (!contract) {
     return;
@@ -106,15 +141,19 @@ const renderView = (viewId) => {
   state.activeView = viewId;
   updateSidebar(viewId);
 
+  if (guideSidebar.isExpanded()) {
+    guideSidebar.close();
+  }
+
   currentViewContract = {
     ...contract,
-    extraFocusRoots: SIDEBAR_HIDDEN_VIEWS.has(viewId) ? [] : [document.querySelector("#sidebar")],
+    extraFocusRoots: SIDEBAR_HIDDEN_VIEWS.has(viewId) ? [] : guideSidebar.getFocusRoots(),
   };
 
   nav.mount(currentViewContract);
   setFooterHints(currentViewContract.hintsTemplate ?? "#global-hints-template", state.glyphs);
   updateClockLabels();
-};
+}
 
 const refreshNavigation = (event) => {
   if (!currentViewContract?.focusRoot) {
@@ -123,14 +162,12 @@ const refreshNavigation = (event) => {
 
   const focusKey = event?.detail?.focusKey;
   const requestedFocus = focusKey
-    ? currentViewContract.focusRoot.querySelector(`[data-focus-key="${CSS.escape(focusKey)}"]`)
+    ? document.querySelector(`[data-focus-key="${CSS.escape(focusKey)}"]`)
     : null;
 
-  currentViewContract = {
+  remountNavigation({
-    ...currentViewContract,
     defaultFocus: requestedFocus ?? currentViewContract.defaultFocus,
-  };
+  });
-  nav.mount(currentViewContract);
 };
 
 const registerViews = () => {
@@ -140,15 +177,47 @@ const registerViews = () => {
   router.register(createHomeView(context));
   router.register(createSettingsView(context));
   router.register(createLibraryView(context));
+  router.register(
+    createPlaceholderView(context, {
+      id: "store",
+      title: "Store",
+      subtitle: "Discover",
+    }),
+  );
+  router.register(
+    createPlaceholderView(context, {
+      id: "mods",
+      title: "Mods",
+      subtitle: "Community",
+    }),
+  );
 };
 
-const openPowerMenu = () => {
+function openPowerMenu() {
+  if (guideSidebar.isExpanded()) {
+    guideSidebar.close();
+  }
   powerMenu.open({
     onClose: () => {
-      nav.mount(currentViewContract);
+      remountNavigation();
       setFooterHints(currentViewContract?.hintsTemplate ?? "#global-hints-template", state.glyphs);
     },
   });
+  setFooterHints("#minimal-hints-template", state.glyphs);
+}
+
+const toggleGuide = () => {
+  if (SIDEBAR_HIDDEN_VIEWS.has(state.activeView)) {
+    return;
+  }
+  guideSidebar.toggle();
+};
+
+const handleGuideAccept = (focused) => {
+  const handled = guideSidebar.handleAccept(focused);
+  if (handled) {
+    remountNavigation({ focusKey: focused?.dataset?.focusKey });
+  }
 };
 
 const handleAction = (action) => {
@@ -157,6 +226,12 @@ const handleAction = (action) => {
     return;
   }
 
+  if (guidePanels.isOpen()) {
+    if (guidePanels.handleAction(action)) {
+      return;
+    }
+  }
+
   if (keyboard.isOpen()) {
     const consumed = keyboard.handleAction(action);
     if (consumed) {
@@ -168,11 +243,40 @@ const handleAction = (action) => {
     return;
   }
 
+  if (action === "guide") {
+    toggleGuide();
+    return;
+  }
+
   if (action === "menu") {
-    const handled = currentViewContract.onMenu?.();
+    if (guideSidebar.isExpanded()) {
-    if (handled !== false) {
+      guideSidebar.close();
-      openPowerMenu();
+      return;
     }
+    toggleGuide();
+    return;
+  }
+
+  if (guideSidebar.isExpanded()) {
+    if (action === "back") {
+      guideSidebar.close();
+      return;
+    }
+
+    if (action === "up" || action === "down" || action === "left" || action === "right") {
+      nav.move(action);
+      emitUiHook("move", { action });
+      return;
+    }
+
+    if (action === "accept") {
+      const focused = nav.getFocusedElement();
+      focused?.classList.add("is-pressed");
+      window.setTimeout(() => focused?.classList.remove("is-pressed"), 180);
+      handleGuideAccept(focused);
+      return;
+    }
+
     return;
   }
 
@@ -196,8 +300,16 @@ const handleAction = (action) => {
     emitUiHook("accept", { focusKey: focused?.dataset.focusKey ?? null });
 
     if (focused?.dataset.navRegion === "sidebar") {
+      if (focused.dataset.guideAction === "toggle") {
+        guideSidebar.open();
+        return;
+      }
+      if (focused.dataset.guideAction === "power") {
+        openPowerMenu();
+        return;
+      }
       const target = focused.dataset.target;
-      if (target && SIDEBAR_NAV_VIEWS.has(target)) {
+      if (target && NAVIGABLE_VIEWS.has(target)) {
         renderView(target);
       }
       return;
@@ -217,6 +329,11 @@ const handleAction = (action) => {
 };
 
 const initialize = async () => {
+  guideSidebar.mount({
+    shellRoot: guideShellRoot,
+    backdropRoot: guideBackdrop,
+  });
+
   await state.initializeUser();
   await state.initializeNebulaCore();
   registerViews();
@@ -224,12 +341,38 @@ const initialize = async () => {
   updateClockLabels();
   window.setInterval(updateClockLabels, 1000);
 
-  const input = createInputManager({
+  window.addEventListener("nebula-navigation-refresh", refreshNavigation);
-    onAction: handleAction,
+  window.addEventListener("nebula-guide-close", (event) => {
-    actions: ["up", "down", "left", "right", "accept", "back", "menu", "clear", "y", "l1", "r1", "l2", "r2"],
+    remountNavigation({ focusKey: event.detail?.focusKey });
+  });
+
+  window.addEventListener("keydown", (event) => {
+    if (event.key === "Escape" && guideSidebar.isExpanded()) {
+      event.preventDefault();
+      guideSidebar.close();
+    }
+  });
+
+  const input = createInputManager({
+    onAction: handleAction,
+    actions: [
+      "up",
+      "down",
+      "left",
+      "right",
+      "accept",
+      "back",
+      "menu",
+      "guide",
+      "clear",
+      "y",
+      "l1",
+      "r1",
+      "l2",
+      "r2",
+    ],
   });
 
-  window.addEventListener("nebula-navigation-refresh", refreshNavigation);
   input.start();
 };
 

src/styles/base.css

@@ -63,127 +63,10 @@ body {
   z-index: 0;
 }
 
-/* ─── Left sidebar ─── */
+/* ─── Guide sidebar mount ─── */
-.sidebar {
+.guide-mount {
-  width: 82px;
   flex-shrink: 0;
   height: 100%;
-  background: var(--nebula-color-sidebar);
-  border-right: 1px solid rgba(79, 216, 255, 0.1);
-  display: flex;
-  flex-direction: column;
-  align-items: center;
-  padding: 18px 0 16px;
-  z-index: 10;
-}
-
-.body-no-sidebar .sidebar {
-  display: none;
-}
-
-.sidebar-logo {
-  display: flex;
-  flex-direction: column;
-  align-items: center;
-  gap: 5px;
-  margin-bottom: 20px;
-}
-
-.sidebar-logo-icon {
-  width: 46px;
-  height: 46px;
-  border-radius: 50%;
-  background: radial-gradient(circle at 38% 35%, rgba(79, 216, 255, 0.7) 0%, rgba(157, 79, 224, 0.85) 60%, rgba(40, 20, 80, 1) 100%);
-  border: 1.5px solid rgba(79, 216, 255, 0.35);
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  font-size: 18px;
-  line-height: 1;
-}
-
-.sidebar-logo-text {
-  font-size: 8px;
-  font-weight: 700;
-  letter-spacing: 0.1em;
-  text-transform: uppercase;
-  color: var(--nebula-color-muted);
-  text-align: center;
-}
-
-.sidebar-nav {
-  display: flex;
-  flex-direction: column;
-  align-items: stretch;
-  gap: 2px;
-  flex: 1;
-  list-style: none;
-  padding: 0;
-  margin: 0;
-  width: 100%;
-}
-
-.sidebar-nav-item {
-  display: flex;
-  flex-direction: column;
-  align-items: center;
-  justify-content: center;
-  gap: 4px;
-  padding: 11px 0;
-  cursor: pointer;
-  color: var(--nebula-color-muted);
-  border-left: 3px solid transparent;
-  border-right: 3px solid transparent;
-  transition:
-    color var(--nebula-duration-fast) var(--nebula-ease-standard),
-    background var(--nebula-duration-fast) var(--nebula-ease-standard),
-    border-left-color var(--nebula-duration-fast) var(--nebula-ease-standard);
-}
-
-.sidebar-nav-item.is-active {
-  color: var(--nebula-color-text);
-  background: rgba(79, 216, 255, 0.07);
-  border-left-color: var(--nebula-color-accent);
-}
-
-.sidebar-nav-item.is-focused {
-  color: var(--nebula-color-text);
-  background: rgba(79, 216, 255, 0.12);
-  border-left-color: var(--nebula-color-accent);
-  border-right-color: var(--nebula-color-purple);
-  transform: none;
-}
-
-.sidebar-nav-item[data-disabled="true"] {
-  opacity: 0.55;
-}
-
-.sidebar-nav-icon {
-  font-size: 19px;
-  line-height: 1;
-}
-
-.sidebar-nav-label {
-  font-size: 9px;
-  font-weight: 600;
-  letter-spacing: 0.04em;
-}
-
-.sidebar-user {
-  display: flex;
-  flex-direction: column;
-  align-items: center;
-  padding-top: 14px;
-  border-top: 1px solid rgba(255, 255, 255, 0.06);
-  width: 100%;
-}
-
-.sidebar-user-avatar {
-  width: 34px;
-  height: 34px;
-  border-radius: 50%;
-  background: radial-gradient(circle at 34% 30%, rgba(255, 255, 255, 0.85), rgba(108, 180, 255, 0.5));
-  border: 2px solid rgba(79, 216, 255, 0.25);
 }
 
 /* ─── Main content area ─── */
@@ -196,6 +79,28 @@ body {
   min-width: 0;
 }
 
+.placeholder-view .placeholder-body {
+  margin: var(--nebula-spacing-lg);
+  max-width: 720px;
+}
+
+.placeholder-copy {
+  margin: var(--nebula-spacing-md) 0 var(--nebula-spacing-lg);
+  color: var(--nebula-color-muted);
+  line-height: 1.5;
+}
+
+.placeholder-back {
+  min-height: 52px;
+  padding: 0 var(--nebula-spacing-lg);
+  border: none;
+  border-radius: var(--nebula-radius-pill);
+  background: var(--nebula-color-panel-alt);
+  color: var(--nebula-color-text);
+  font-weight: 600;
+  cursor: pointer;
+}
+
 .app-shell {
   flex: 1;
   min-height: 0;

src/styles/components.css

@@ -27,7 +27,9 @@
   transform: scale(1.03) translateZ(0);
 }
 
-.sidebar-nav-item.focusable.is-focused {
+.sidebar-nav-item.focusable.is-focused,
+.guide-rail-item.focusable.is-focused,
+.guide-nav-item.focusable.is-focused {
   border-top-color: transparent;
   border-bottom-color: transparent;
   border-left-color: var(--nebula-color-accent);

src/styles/guide.css

@@ -0,0 +1,622 @@
+/* ─── Nebula guide sidebar (Xbox-inspired shell navigation) ─── */
+
+:root {
+  --guide-rail-width: 88px;
+  --guide-panel-width: min(400px, 92vw);
+  --guide-glass: rgba(8, 10, 22, 0.92);
+  --guide-glass-border: rgba(79, 216, 255, 0.14);
+  --guide-accent-glow: rgba(79, 216, 255, 0.35);
+}
+
+.guide-shell {
+  position: relative;
+  flex-shrink: 0;
+  width: var(--guide-rail-width);
+  height: 100%;
+  z-index: 30;
+}
+
+.body-no-sidebar .guide-shell,
+.body-no-sidebar .guide-backdrop {
+  display: none;
+}
+
+/* ─── Collapsed rail ─── */
+.guide-rail {
+  width: var(--guide-rail-width);
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  padding: 14px 0 12px;
+  background: linear-gradient(180deg, rgba(10, 12, 24, 0.98) 0%, rgba(7, 9, 18, 0.98) 100%);
+  border-right: 1px solid var(--guide-glass-border);
+  transition: opacity var(--nebula-duration-nav) var(--nebula-ease-standard);
+}
+
+.guide-expanded .guide-rail {
+  opacity: 0;
+  pointer-events: none;
+}
+
+.guide-rail-brand {
+  width: 52px;
+  height: 52px;
+  border-radius: 50%;
+  border: 1.5px solid rgba(79, 216, 255, 0.3);
+  background: radial-gradient(circle at 38% 32%, rgba(79, 216, 255, 0.55), rgba(157, 79, 224, 0.75) 55%, rgba(30, 16, 60, 1));
+  color: var(--nebula-color-text);
+  display: grid;
+  place-items: center;
+  margin-bottom: 18px;
+  cursor: pointer;
+  padding: 0;
+}
+
+.guide-brand-mark {
+  font-size: 20px;
+  line-height: 1;
+  text-shadow: 0 0 12px var(--guide-accent-glow);
+}
+
+.guide-rail-nav {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+  width: 100%;
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+}
+
+.guide-rail-item {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  min-height: 52px;
+  margin: 0 8px;
+  border-radius: var(--nebula-radius-md);
+  border: 2px solid transparent;
+  border-left: 3px solid transparent;
+  color: var(--nebula-color-muted);
+  cursor: pointer;
+  transition:
+    color var(--nebula-duration-fast) var(--nebula-ease-standard),
+    background var(--nebula-duration-fast) var(--nebula-ease-standard),
+    border-color var(--nebula-duration-fast) var(--nebula-ease-standard),
+    box-shadow var(--nebula-duration-fast) var(--nebula-ease-standard);
+}
+
+.guide-rail-item.is-active {
+  color: var(--nebula-color-text);
+  background: rgba(79, 216, 255, 0.08);
+  border-left-color: var(--nebula-color-accent);
+  box-shadow: inset 3px 0 0 var(--nebula-color-accent);
+}
+
+.guide-rail-item.is-focused {
+  color: var(--nebula-color-text);
+  background: rgba(79, 216, 255, 0.14);
+  border-color: rgba(79, 216, 255, 0.45);
+  border-left-color: var(--nebula-color-accent);
+  box-shadow:
+    0 0 0 1px rgba(79, 216, 255, 0.25),
+    0 0 18px rgba(79, 216, 255, 0.12);
+  transform: none;
+}
+
+.guide-rail-icon {
+  font-size: 22px;
+  line-height: 1;
+}
+
+.guide-rail-footer {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 10px;
+  padding-top: 12px;
+  border-top: 1px solid rgba(255, 255, 255, 0.06);
+  width: 100%;
+}
+
+.guide-rail-expand,
+.guide-rail-profile {
+  width: 48px;
+  height: 48px;
+  border-radius: var(--nebula-radius-md);
+  border: 2px solid transparent;
+  background: rgba(255, 255, 255, 0.04);
+  color: var(--nebula-color-muted);
+  cursor: pointer;
+  display: grid;
+  place-items: center;
+  padding: 0;
+}
+
+.guide-rail-expand.is-focused,
+.guide-rail-profile.is-focused {
+  border-color: var(--nebula-color-accent);
+  color: var(--nebula-color-text);
+  transform: none;
+}
+
+.guide-rail-expand-icon {
+  font-size: 20px;
+}
+
+.guide-rail-avatar {
+  width: 34px;
+  height: 34px;
+  border-radius: 50%;
+  display: grid;
+  place-items: center;
+  font-size: 12px;
+  font-weight: 700;
+  background: linear-gradient(145deg, rgba(79, 216, 255, 0.35), rgba(157, 79, 224, 0.5));
+  border: 2px solid rgba(79, 216, 255, 0.35);
+  color: var(--nebula-color-text);
+}
+
+/* ─── Expanded guide panel (overlay) ─── */
+.guide-panel {
+  position: fixed;
+  left: 0;
+  top: 0;
+  bottom: 0;
+  width: var(--guide-panel-width);
+  z-index: 35;
+  transform: translateX(-104%);
+  transition: transform var(--nebula-duration-slow) var(--nebula-ease-console);
+  pointer-events: none;
+}
+
+.guide-expanded .guide-panel {
+  transform: translateX(0);
+  pointer-events: auto;
+}
+
+.guide-panel-inner {
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+  background: var(--guide-glass);
+  backdrop-filter: blur(20px) saturate(1.2);
+  -webkit-backdrop-filter: blur(20px) saturate(1.2);
+  border-right: 1px solid var(--guide-glass-border);
+  box-shadow:
+    8px 0 40px rgba(0, 0, 0, 0.45),
+    inset -1px 0 0 rgba(157, 79, 224, 0.12);
+}
+
+.guide-header {
+  padding: 20px 22px 16px;
+  display: grid;
+  gap: 12px;
+}
+
+.guide-profile {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+}
+
+.guide-profile-avatar,
+.guide-footer-avatar {
+  width: 48px;
+  height: 48px;
+  border-radius: 50%;
+  display: grid;
+  place-items: center;
+  font-size: 15px;
+  font-weight: 700;
+  flex-shrink: 0;
+  background: linear-gradient(145deg, rgba(79, 216, 255, 0.4), rgba(157, 79, 224, 0.55));
+  border: 2px solid rgba(79, 216, 255, 0.4);
+  color: var(--nebula-color-text);
+  box-shadow: 0 0 20px rgba(79, 216, 255, 0.15);
+}
+
+.guide-profile-name {
+  margin: 0;
+  font-size: 20px;
+  font-weight: 700;
+  letter-spacing: -0.02em;
+}
+
+.guide-profile-status {
+  margin: 4px 0 0;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  font-size: 13px;
+  color: var(--nebula-color-muted);
+}
+
+.guide-status-dot {
+  width: 8px;
+  height: 8px;
+  border-radius: 50%;
+  background: var(--nebula-color-success);
+  box-shadow: 0 0 8px rgba(79, 255, 136, 0.6);
+}
+
+.guide-header-meta {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.guide-header-time {
+  margin: 0;
+  font-size: 22px;
+  font-weight: 600;
+  font-variant-numeric: tabular-nums;
+}
+
+.guide-header-date {
+  margin: 2px 0 0;
+  font-size: 12px;
+  color: var(--nebula-color-muted);
+}
+
+.guide-header-indicators {
+  display: flex;
+  gap: 10px;
+  color: var(--nebula-color-accent);
+  font-size: 14px;
+  opacity: 0.85;
+}
+
+.guide-header-brand {
+  margin: 0;
+  font-size: 11px;
+  font-weight: 700;
+  letter-spacing: 0.14em;
+  text-transform: uppercase;
+  color: var(--nebula-color-muted);
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.guide-header-brand-mark {
+  color: var(--nebula-color-accent);
+  text-shadow: 0 0 10px var(--guide-accent-glow);
+}
+
+.guide-divider {
+  border: none;
+  height: 1px;
+  margin: 0 18px;
+  background: linear-gradient(90deg, transparent, rgba(79, 216, 255, 0.2), transparent);
+}
+
+.guide-section {
+  padding: 12px 18px;
+  min-height: 0;
+}
+
+.guide-section-recent {
+  flex: 1;
+  overflow: hidden;
+  display: flex;
+  flex-direction: column;
+}
+
+.guide-section-title {
+  margin: 0 0 10px;
+  font-size: 11px;
+  font-weight: 700;
+  letter-spacing: 0.12em;
+  text-transform: uppercase;
+  color: var(--nebula-color-muted);
+}
+
+.guide-nav-list {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.guide-nav-item {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+  min-height: 48px;
+  padding: 0 14px;
+  border-radius: var(--nebula-radius-md);
+  border: 2px solid transparent;
+  border-left: 3px solid transparent;
+  color: var(--nebula-color-muted);
+  cursor: pointer;
+  transition:
+    background var(--nebula-duration-fast) var(--nebula-ease-standard),
+    border-color var(--nebula-duration-fast) var(--nebula-ease-standard),
+    color var(--nebula-duration-fast) var(--nebula-ease-standard);
+}
+
+.guide-nav-item.is-active {
+  color: var(--nebula-color-text);
+  background: rgba(79, 216, 255, 0.08);
+  border-left-color: var(--nebula-color-accent);
+}
+
+.guide-nav-item.is-active::after {
+  content: "";
+  margin-left: auto;
+  width: 6px;
+  height: 6px;
+  border-radius: 50%;
+  background: var(--nebula-color-accent);
+  box-shadow: 0 0 8px var(--guide-accent-glow);
+}
+
+.guide-nav-item.is-focused {
+  color: var(--nebula-color-text);
+  background: rgba(79, 216, 255, 0.16);
+  border-color: rgba(79, 216, 255, 0.45);
+  border-left-color: var(--nebula-color-accent);
+  box-shadow: 0 0 22px rgba(79, 216, 255, 0.1);
+  transform: none;
+}
+
+.guide-nav-icon {
+  font-size: 20px;
+  width: 28px;
+  text-align: center;
+}
+
+.guide-nav-label {
+  font-size: 16px;
+  font-weight: 600;
+}
+
+.guide-quick-grid {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 8px;
+}
+
+.guide-quick-item {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  min-height: 44px;
+  padding: 8px 12px;
+  border-radius: var(--nebula-radius-md);
+  border: 2px solid transparent;
+  background: rgba(255, 255, 255, 0.03);
+  color: var(--nebula-color-muted);
+  cursor: pointer;
+  text-align: left;
+  font: inherit;
+}
+
+.guide-quick-item.is-focused {
+  border-color: var(--nebula-color-accent);
+  color: var(--nebula-color-text);
+  background: rgba(79, 216, 255, 0.12);
+  transform: none;
+}
+
+.guide-quick-icon {
+  font-size: 16px;
+  opacity: 0.9;
+}
+
+.guide-quick-label {
+  font-size: 13px;
+  font-weight: 600;
+}
+
+.guide-recent-list {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  overflow-y: auto;
+  padding-right: 4px;
+  max-height: min(220px, 28vh);
+}
+
+.guide-recent-item {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  width: 100%;
+  min-height: 56px;
+  padding: 8px 10px;
+  border-radius: var(--nebula-radius-md);
+  border: 2px solid transparent;
+  background: rgba(255, 255, 255, 0.02);
+  color: var(--nebula-color-text);
+  cursor: pointer;
+  text-align: left;
+  font: inherit;
+}
+
+.guide-recent-item.is-focused {
+  border-color: var(--nebula-color-accent);
+  background: rgba(79, 216, 255, 0.1);
+  transform: none;
+}
+
+.guide-recent-cover {
+  width: 40px;
+  height: 40px;
+  border-radius: var(--nebula-radius-sm);
+  flex-shrink: 0;
+  background: linear-gradient(135deg, var(--recent-accent, #1a2a44), rgba(0, 0, 0, 0.5));
+  border: 1px solid rgba(255, 255, 255, 0.1);
+}
+
+.guide-recent-meta {
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+  min-width: 0;
+}
+
+.guide-recent-title {
+  font-size: 14px;
+  font-weight: 600;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.guide-recent-sub {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  font-size: 11px;
+  color: var(--nebula-color-muted);
+}
+
+.guide-source-badge {
+  padding: 2px 7px;
+  border-radius: var(--nebula-radius-pill);
+  font-size: 10px;
+  font-weight: 700;
+  letter-spacing: 0.04em;
+  text-transform: uppercase;
+  background: rgba(79, 216, 255, 0.12);
+  color: var(--nebula-color-accent);
+}
+
+.guide-source-badge[data-source="steam"] {
+  background: rgba(27, 40, 56, 0.9);
+  color: #66c0f4;
+}
+
+.guide-source-badge[data-source="gog"] {
+  background: rgba(60, 20, 90, 0.5);
+  color: #c9a0ff;
+}
+
+.guide-source-badge[data-source="epic"] {
+  background: rgba(30, 30, 30, 0.8);
+  color: #f0f0f0;
+}
+
+.guide-recent-empty {
+  padding: 20px 12px;
+  text-align: center;
+  border-radius: var(--nebula-radius-md);
+  border: 1px dashed rgba(255, 255, 255, 0.1);
+  background: rgba(0, 0, 0, 0.2);
+}
+
+.guide-recent-empty-icon {
+  font-size: 28px;
+  opacity: 0.4;
+  display: block;
+  margin-bottom: 8px;
+}
+
+.guide-recent-empty-title {
+  margin: 0 0 6px;
+  font-weight: 600;
+}
+
+.guide-recent-empty-copy {
+  margin: 0;
+  font-size: 13px;
+  color: var(--nebula-color-muted);
+}
+
+.guide-footer {
+  margin-top: auto;
+  padding: 14px 18px 16px;
+  border-top: 1px solid rgba(255, 255, 255, 0.06);
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 8px;
+}
+
+.guide-footer-btn {
+  display: inline-flex;
+  align-items: center;
+  gap: 8px;
+  min-height: 40px;
+  padding: 0 12px;
+  border-radius: var(--nebula-radius-pill);
+  border: 2px solid transparent;
+  background: rgba(255, 255, 255, 0.04);
+  color: var(--nebula-color-muted);
+  font-size: 13px;
+  font-weight: 600;
+  cursor: pointer;
+  font: inherit;
+}
+
+.guide-footer-btn.is-focused {
+  border-color: var(--nebula-color-accent);
+  color: var(--nebula-color-text);
+  transform: none;
+}
+
+.guide-footer-avatar {
+  width: 28px;
+  height: 28px;
+  font-size: 10px;
+}
+
+.guide-version {
+  flex: 1 1 100%;
+  margin: 6px 0 0;
+  font-size: 11px;
+  color: var(--nebula-color-muted);
+  opacity: 0.75;
+}
+
+/* Dim layer over content when guide is open */
+.guide-backdrop {
+  position: fixed;
+  inset: 0;
+  z-index: 25;
+  background: rgba(3, 5, 14, 0.62);
+  backdrop-filter: blur(2px);
+  -webkit-backdrop-filter: blur(2px);
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity var(--nebula-duration-slow) var(--nebula-ease-standard);
+}
+
+body.guide-expanded .guide-backdrop,
+.guide-backdrop:not([hidden]) {
+  opacity: 1;
+  pointer-events: auto;
+}
+
+.guide-backdrop[hidden] {
+  display: block !important;
+  opacity: 0;
+  pointer-events: none;
+}
+
+/* Focus overrides for guide items */
+.guide-rail-item.focusable.is-focused,
+.guide-nav-item.focusable.is-focused,
+.guide-quick-item.focusable.is-focused,
+.guide-recent-item.focusable.is-focused,
+.guide-footer-btn.focusable.is-focused,
+.guide-rail-brand.focusable.is-focused,
+.guide-rail-expand.focusable.is-focused,
+.guide-rail-profile.focusable.is-focused {
+  transform: none;
+}
+
+@media (max-width: 720px) {
+  :root {
+    --guide-rail-width: 72px;
+    --guide-panel-width: min(100vw, 100%);
+  }
+}

src/views/overlays/guidePanel.css

@@ -0,0 +1,105 @@
+.guide-panel-overlay {
+  position: fixed;
+  inset: 0;
+  z-index: 40;
+  display: grid;
+  place-items: center;
+  padding: var(--nebula-spacing-lg);
+  background: var(--nebula-color-overlay);
+}
+
+.guide-panel-overlay[hidden] {
+  display: none !important;
+}
+
+.guide-panel-sheet {
+  width: min(560px, 94vw);
+  max-height: min(80vh, 640px);
+  display: flex;
+  flex-direction: column;
+  gap: var(--nebula-spacing-md);
+}
+
+.guide-panel-sheet-head {
+  margin: 0;
+}
+
+.guide-panel-sheet-title {
+  margin: 0 0 var(--nebula-spacing-xs);
+}
+
+.guide-panel-sheet-desc {
+  margin: 0;
+}
+
+.guide-panel-sheet-body {
+  flex: 1;
+  min-height: 120px;
+}
+
+.guide-panel-search-input {
+  width: 100%;
+  min-height: 52px;
+  padding: 0 var(--nebula-spacing-md);
+  border-radius: var(--nebula-radius-md);
+  border: 1px solid var(--nebula-color-border-mid);
+  background: var(--nebula-color-panel-alt);
+  color: var(--nebula-color-text);
+  font-size: 18px;
+}
+
+.guide-panel-search-input:focus {
+  outline: 2px solid var(--nebula-color-accent);
+  outline-offset: 2px;
+}
+
+.guide-panel-hint {
+  margin-top: var(--nebula-spacing-md);
+}
+
+.guide-panel-placeholder-card {
+  padding: var(--nebula-spacing-lg);
+  border-radius: var(--nebula-radius-md);
+  border: 1px solid var(--nebula-color-border);
+  background: var(--nebula-color-panel-alt);
+}
+
+.guide-panel-placeholder-title {
+  margin: 0 0 var(--nebula-spacing-sm);
+  font-size: 18px;
+  font-weight: 700;
+}
+
+.guide-panel-placeholder-note {
+  margin: var(--nebula-spacing-md) 0 0;
+  font-size: 12px;
+  color: var(--nebula-color-muted);
+}
+
+.guide-panel-close {
+  align-self: flex-end;
+  min-height: 48px;
+  padding: 0 var(--nebula-spacing-lg);
+  border: none;
+  border-radius: var(--nebula-radius-pill);
+  background: var(--nebula-color-panel-alt);
+  color: var(--nebula-color-text);
+  font-weight: 600;
+  cursor: pointer;
+}
+
+.guide-panel-close.is-focused {
+  border: 2px solid var(--nebula-color-accent);
+}
+
+.sr-only {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: 0;
+}

src/views/overlays/guidePanel.js

@@ -0,0 +1,152 @@
+const PANEL_COPY = {
+  search: {
+    title: "Search",
+    description: "Search games, apps, and settings across NebulaOS.",
+    placeholder: "Search NebulaOS…",
+  },
+  notifications: {
+    title: "Notifications",
+    description: "System alerts and download updates will appear here.",
+  },
+  downloads: {
+    title: "Downloads",
+    description: "Active and completed downloads will be listed here.",
+  },
+  controller: {
+    title: "Controller Settings",
+    description: "Map buttons, adjust dead zones, and test input.",
+  },
+};
+
+export const createGuidePanelOverlay = ({ mountRoot }) => {
+  let openState = false;
+  let activePanel = null;
+  let onClose = null;
+  let overlay = null;
+
+  const renderMarkup = () => {
+    mountRoot.insertAdjacentHTML(
+      "beforeend",
+      `
+      <section class="guide-panel-overlay" data-guide-panel-overlay hidden aria-label="Guide panel">
+        <div class="guide-panel-sheet panel" role="dialog" aria-modal="true">
+          <header class="guide-panel-sheet-head">
+            <h2 class="guide-panel-sheet-title" data-panel-title>Panel</h2>
+            <p class="muted guide-panel-sheet-desc" data-panel-desc></p>
+          </header>
+          <div class="guide-panel-sheet-body" data-panel-body></div>
+          <button
+            type="button"
+            class="focusable guide-panel-close"
+            data-focusable="true"
+            data-row="0"
+            data-col="0"
+            data-action="close"
+            data-focus-key="guide-panel-close"
+          >Close</button>
+        </div>
+      </section>
+    `,
+    );
+    overlay = mountRoot.querySelector("[data-guide-panel-overlay]");
+  };
+
+  const getBodyHtml = (panelId) => {
+    const copy = PANEL_COPY[panelId];
+    if (!copy) {
+      return `<p class="muted">This panel is not available yet.</p>`;
+    }
+
+    if (panelId === "search") {
+      return `
+        <label class="guide-panel-search-label">
+          <span class="sr-only">Search query</span>
+          <input
+            type="search"
+            class="guide-panel-search-input"
+            placeholder="${copy.placeholder}"
+            data-panel-search
+            autocomplete="off"
+          />
+        </label>
+        <p class="muted guide-panel-hint">Results will appear here. (Placeholder)</p>
+      `;
+    }
+
+    return `
+      <div class="guide-panel-placeholder-card">
+        <p class="guide-panel-placeholder-title">${copy.title}</p>
+        <p class="muted">${copy.description}</p>
+        <p class="guide-panel-placeholder-note">Connected to guide quick actions · stub UI</p>
+      </div>
+    `;
+  };
+
+  const close = () => {
+    openState = false;
+    activePanel = null;
+    if (overlay) {
+      overlay.hidden = true;
+    }
+    onClose?.();
+    onClose = null;
+  };
+
+  const bindOverlayEvents = () => {
+    overlay?.addEventListener("click", (event) => {
+      if (event.target === overlay) {
+        close();
+      }
+    });
+    overlay?.querySelector(".guide-panel-close")?.addEventListener("click", () => close());
+  };
+
+  const open = (panelId, options = {}) => {
+    if (!overlay) {
+      renderMarkup();
+      bindOverlayEvents();
+    }
+
+    const copy = PANEL_COPY[panelId] ?? { title: "Panel", description: "" };
+    overlay.querySelector("[data-panel-title]").textContent = copy.title;
+    overlay.querySelector("[data-panel-desc]").textContent = copy.description ?? "";
+    overlay.querySelector("[data-panel-body]").innerHTML = getBodyHtml(panelId);
+
+    openState = true;
+    activePanel = panelId;
+    onClose = options.onClose ?? null;
+    overlay.hidden = false;
+
+    const closeBtn = overlay.querySelector("[data-guide-panel-close], .guide-panel-close");
+    closeBtn?.focus({ preventScroll: true });
+    closeBtn?.classList.add("is-focused");
+
+    console.log(`[GuidePanel] Opened: ${panelId}`);
+  };
+
+  const handleAction = (action) => {
+    if (!openState) {
+      return false;
+    }
+
+    if (action === "accept") {
+      close();
+      return true;
+    }
+
+    if (action === "back" || action === "menu") {
+      close();
+      return true;
+    }
+
+    return true;
+  };
+
+  return {
+    open,
+    close,
+    isOpen: () => openState,
+    getActivePanel: () => activePanel,
+    handleAction,
+  };
+};

src/views/overlays/powerMenu.js

@@ -3,10 +3,10 @@ const POWER_MENU_TEMPLATE = `
   <div class="power-panel panel">
     <h2 class="power-title">Power Menu</h2>
     <div class="power-options" data-power-focus-root>
-      <button class="focusable power-option" data-focusable="true" data-row="0" data-col="0" data-action="suspend">Suspend</button>
+      <button class="focusable power-option" data-focusable="true" data-row="0" data-col="0" data-action="sleep">Sleep</button>
-      <button class="focusable power-option" data-focusable="true" data-row="1" data-col="0" data-action="restart">Restart</button>
+      <button class="focusable power-option" data-focusable="true" data-row="1" data-col="0" data-action="restart-nebula">Restart NebulaOS</button>
-      <button class="focusable power-option" data-focusable="true" data-row="2" data-col="0" data-action="shutdown">Shutdown</button>
+      <button class="focusable power-option" data-focusable="true" data-row="2" data-col="0" data-action="restart-system">Restart System</button>
-      <button class="focusable power-option" data-focusable="true" data-row="3" data-col="0" data-action="desktop">Switch to Desktop</button>
+      <button class="focusable power-option" data-focusable="true" data-row="3" data-col="0" data-action="shutdown">Shut Down</button>
       <button class="focusable power-option" data-focusable="true" data-row="4" data-col="0" data-action="cancel">Cancel</button>
     </div>
   </div>
@@ -14,17 +14,17 @@ const POWER_MENU_TEMPLATE = `
 `;
 
 const ACTION_LOG = {
-  suspend: "Suspend requested (stub)",
+  sleep: "Sleep requested (stub)",
-  restart: "Restart requested (stub)",
+  "restart-nebula": "Restart NebulaOS requested (stub)",
-  shutdown: "Shutdown requested (stub)",
+  "restart-system": "Restart System requested (stub)",
-  desktop: "Switch to Desktop requested (stub)",
+  shutdown: "Shut Down requested (stub)",
 };
 
 export const createPowerMenuOverlay = ({ mountRoot }) => {
-  mountRoot.innerHTML = POWER_MENU_TEMPLATE;
+  mountRoot.insertAdjacentHTML("beforeend", POWER_MENU_TEMPLATE);
 
   const overlay = mountRoot.querySelector("[data-power-overlay]");
-  const focusables = Array.from(mountRoot.querySelectorAll("[data-focusable='true']"));
+  const focusables = Array.from(overlay?.querySelectorAll("[data-focusable='true']") ?? []);
   let focusedIndex = 0;
   let openState = false;
   let onClose = null;

src/views/placeholder/placeholder.js

@@ -0,0 +1,50 @@
+export const createPlaceholderView = (context, { id, title, subtitle, backTarget = "home" }) => ({
+  id,
+  render: () => `
+    <section class="view placeholder-view" data-view="${id}">
+      <header class="shell-topbar">
+        <div class="shell-topbar-content">
+          <p class="shell-brand">Nebula OS</p>
+          <div class="shell-status">
+            <span class="shell-avatar" aria-hidden="true"></span>
+            <p class="shell-time" data-clock>--:--</p>
+          </div>
+        </div>
+        <div class="shell-accent-line"></div>
+      </header>
+      <section class="placeholder-body panel" data-focus-root>
+        <p class="muted">${subtitle}</p>
+        <h1 class="view-title">${title}</h1>
+        <p class="placeholder-copy">This area is part of the NebulaOS shell roadmap. Navigation is wired; content ships in a future update.</p>
+        <button
+          type="button"
+          class="focusable placeholder-back"
+          data-focusable="true"
+          data-row="0"
+          data-col="0"
+          data-target="${backTarget}"
+          data-focus-key="placeholder-back"
+        >Back to Home</button>
+      </section>
+    </section>
+  `,
+  mount() {},
+  getNavigationContract: () => {
+    const focusRoot = document.querySelector(`[data-view="${id}"] [data-focus-root]`);
+    const defaultFocus = focusRoot?.querySelector("[data-focusable='true']");
+    return {
+      focusRoot,
+      defaultFocus,
+      hintsTemplate: "#global-hints-template",
+      onAccept(focused) {
+        const target = focused?.dataset?.target;
+        if (target) {
+          context.renderView(target);
+        }
+      },
+      onBack() {
+        context.renderView(backTarget);
+      },
+    };
+  },
+});