diff --git a/frontend/src/lib/components/layout/TopNavbar.svelte b/frontend/src/lib/components/layout/TopNavbar.svelte
index 7be029ba5..1d1ef00d3 100644
--- a/frontend/src/lib/components/layout/TopNavbar.svelte
+++ b/frontend/src/lib/components/layout/TopNavbar.svelte
@@ -2,105 +2,70 @@
 <!-- @ingroup Layout -->
 <!-- @BRIEF Unified top navigation bar with Logo, global search, environment selector, activity indicator, user menu, and assistant toggle. -->
 <!-- @LAYER UI -->
+<!-- @PRE Auth token initialized via root +layout.svelte. Environment context store loaded. -->
+<!-- @POST Search state delegated to TopNavbar.Model. User menu, environment, and activity controls synchronized with store state. -->
+<!-- @SIDE_EFFECT Navigates to /agent on assistant click. Triggers window.location.href for logout. Opens task drawer. Calls setSelectedEnvironment. -->
+<!-- @DATA_CONTRACT SearchQuery → TopNavbar.Model.triggerSearch | EnvironmentChange → setSelectedEnvironment | ActivityClick → openDrawerForTask -->
 <!-- @RELATION BINDS_TO -> [EXT:frontend:activityStore] -->
 <!-- @RELATION BINDS_TO -> [EXT:frontend:authStore] -->
 <!-- @RELATION BINDS_TO -> [EXT:frontend:environmentContextStore] -->
 <!-- @RELATION BINDS_TO -> [EXT:frontend:sidebarStore] -->
 <!-- @RELATION BINDS_TO -> [EXT:frontend:taskDrawerStore] -->
+<!-- @RELATION BINDS_TO -> [TopNavbar.Model] -->
 <!-- @RELATION DISPATCHES -> [EXT:frontend:assistantChatStore] -->
 <!-- @RELATION DEPENDS_ON -> [Icon] -->
-<!-- @RELATION DEPENDS_ON -> [LanguageSwitcher] -->
 <!-- @UX_STATE Idle -> Navbar showing current state with all controls. -->
 <!-- @UX_STATE SearchFocused -> Search input expands with focus styling. -->
 <!-- @UX_STATE Searching -> Search dropdown open while async results load. -->
 <!-- @UX_FEEDBACK Activity badge shows count of running tasks. -->
 <!-- @UX_FEEDBACK Environment selector shows PROD context in red. -->
 <!-- @UX_RECOVERY Click outside closes dropdowns. -->
+<!-- @UX_TEST SearchFocused -> {focus: search input, expected: focused style class applied}. -->
+<!-- @UX_TEST ActivityClick -> {click: activity button, expected: task drawer opens}. -->
+<!-- @TEST_CONTRACT Component_TopNavbar -> { required_props: {}, optional_props: {}, invariants: ["Displays user menu and handles logical toggling", "Initiates global search successfully taking debounce into account", "Correctly handles activity notification badge visibility"] } -->
+<!-- @TEST_FIXTURE logged_in -> {"user": {"username": "admin"}} -->
+<!-- @TEST_EDGE network_down -> search fetch fails, handles error state. -->
+<!-- @TEST_INVARIANT ui_consistency -> verifies: [logged_in] -->
+<!-- @RATIONALE Search logic extracted into TopNavbar.Model (reactive screen model) to satisfy INV_7 (module < 400 LOC) and ATTN_4 (sliding-window visibility). The original 605-line inline architecture scattered search state across 7 reactive atoms and 8 functions — the model could not see the full contract under CSA/HCA compression. Model-first extraction puts dense #region anchor at line 1 for maximum first-line density. -->
+<!-- @REJECTED Full decomposition into UserMenuModel + EnvironmentModel + ActivityModel rejected — each concern is ≤ 3 $derived values with simple toggle logic. Per Model Decomposition Gate, inline $state for local UI without cross-widget invariants is the correct call. Inline architecture for those three concerns was rejected (JSDoc duplicates in <script> removed — INV_4: metadata before code, contiguously after opening anchor). -->
 <script lang="ts">
-  /**
-   * @PURPOSE: Unified top navigation bar with Logo, Search, Activity, and User menu
-   * @LAYER UI
-   * @RELATION BINDS_TO -> activity
-   * @RELATION BINDS_TO -> auth
-   * @RELATION BINDS_TO -> environmentContext
-   * @RELATION DISPATCHES -> [EXT:frontend:taskDrawer]
-   * @RELATION DISPATCHES -> assistantChat
-   * @RELATION DEPENDS_ON -> Icon
-   * @RELATION DEPENDS_ON -> LanguageSwitcher
-   * @SEMANTICS: Navigation, UserSession
-   * @PRE: Auth, environment, and task stores are initialized before interactive navbar actions are used.
-   * @POST: Search, environment selection, and global action controls remain synchronized with current app state.
-   * @SIDE_EFFECT: Reads profile preferences, performs search API requests, and triggers drawer, auth, and assistant actions.
-   * @DATA_CONTRACT: SearchQuery -> SearchSection[] | ProfilePreferences -> TaskDrawerPreference
-   * @INVARIANT: Always visible on non-login pages
-   * @UX_REACTIVITY: Uses $state for menu/search state and $derived projections from app stores.
-   *
-   * @UX_STATE: Idle -> Navbar showing current state
-   * @UX_STATE: SearchFocused -> Search input expands
-   * @UX_STATE: Searching -> Search dropdown stays open while async results are loading.
-   * @UX_FEEDBACK: Activity badge shows count of running tasks
-   * @UX_RECOVERY: Click outside closes dropdowns
-   * @UX_TEST: SearchFocused -> {focus: search input, expected: focused style class applied}
-   * @UX_TEST: ActivityClick -> {click: activity button, expected: task drawer opens}
-   *
-   * @TEST_CONTRACT Component_TopNavbar ->
-   * {
-   *   required_props: {},
-   *   optional_props: {},
-   *   invariants: [
-   *       "Displays user menu and handles logical toggling",
-   *       "Initiates global search successfully taking debounce into account",
-   *       "Correctly handles activity notification badge visibility"
-   *   ]
-   * }
-   * @TEST_FIXTURE logged_in -> {"user": {"username": "admin"}}
-   * @TEST_EDGE network_down -> search fetch fails, handles error state
-   * @TEST_INVARIANT ui_consistency -> verifies: [logged_in]
-   */
-
   import { onMount } from "svelte";
   import { log } from "$lib/cot-logger";
   import { goto } from "$app/navigation";
   import { page } from "$app/stores";
   import { ROUTES } from "$lib/routes";
-  import { api } from "$lib/api.js";
-  import { getReports } from "$lib/api/reports.js";
   import { activityStore } from "$lib/stores/activity.svelte.js";
   import {
     openDrawerForTask,
     openDrawer,
-    setTaskDrawerAutoOpenPreference,
   } from "$lib/stores/taskDrawer.svelte.js";
   import { sidebarStore, toggleMobileSidebar } from "$lib/stores/sidebar.svelte.js";
   import { t } from "$lib/i18n/index.svelte.js";
   import { auth } from "$lib/auth/store.svelte.js";
   import { hasPermission } from "$lib/auth/permissions.js";
   import { Icon } from "$lib/ui";
-  import LanguageSwitcher from "$lib/ui/LanguageSwitcher.svelte";
   import {
     environmentContextStore,
     initializeEnvironmentContext,
     setSelectedEnvironment,
     selectedEnvironmentStore,
   } from "$lib/stores/environmentContext.svelte.js";
+  import { TopNavbarModel } from "$lib/models/TopNavbarModel.svelte.ts";
+
+  // ── Model ──────────────────────────────────────────────────────
+  const model = new TopNavbarModel();
+
+  // ── Local UI state (simple toggles, no cross-widget invariants) ─
   let showUserMenu = $state(false);
-  let isSearchFocused = $state(false);
-  let searchQuery = $state("");
-  let showSearchDropdown = $state(false);
-  let isSearchLoading = $state(false);
-  let groupedSearchResults = $state([]);
-  let searchTimer = null;
-
-  const SEARCH_DEBOUNCE_MS = 250;
-  const SEARCH_MIN_LENGTH = 2;
-  const SEARCH_LIMIT = 5;
 
+  // ── Store subscriptions ────────────────────────────────────────
   let _authState = $state({ user: null, token: null, isAuthenticated: false, loading: true });
   onMount(() => {
     const unsub = auth.subscribe(v => { _authState = v; });
     return unsub;
   });
 
+  // ── Derived projections ────────────────────────────────────────
   let isExpanded = $derived(sidebarStore.value?.isExpanded ?? true);
   let activeCount = $derived(activityStore.value?.activeCount || 0);
   let recentTasks = $derived(activityStore.value?.recentTasks || []);
@@ -121,8 +86,8 @@
       Boolean(globalSelectedEnv?.is_production),
   );
 
-  function toggleUserMenu(event) {
-    event.stopPropagation();
+  // ── User menu actions ──────────────────────────────────────────
+  function toggleUserMenu() {
     showUserMenu = !showUserMenu;
   }
 
@@ -136,8 +101,9 @@
     window.location.href = ROUTES.login();
   }
 
+  // ── Activity / Assistant actions ───────────────────────────────
   function handleActivityClick() {
-    const runningTask = recentTasks.find((t) => t.status === "RUNNING");
+    const runningTask = recentTasks.find((t: any) => t.status === "RUNNING");
     if (runningTask) {
       openDrawerForTask(runningTask.taskId);
     } else if (recentTasks.length > 0) {
@@ -155,231 +121,49 @@
     goto(`/agent?${query}`);
   }
 
-  async function hydrateTaskDrawerPreference() {
-    try {
-      const response = await api.getProfilePreferences();
-      const autoOpenTaskDrawer = response?.preference?.auto_open_task_drawer;
-      setTaskDrawerAutoOpenPreference(autoOpenTaskDrawer !== false);
-    } catch (error) {
-      log("TopNavbar", "EXPLORE", "Failed to hydrate task drawer preference", {}, error instanceof Error ? error.message : String(error));
-    }
-  }
-
-  function handleSearchFocus() {
-    isSearchFocused = true;
-    showSearchDropdown = groupedSearchResults.length > 0;
-  }
-
-  function clearSearchState() {
-    showSearchDropdown = false;
-    isSearchLoading = false;
-    groupedSearchResults = [];
-  }
-
-  function handleDocumentClick(event) {
-    if (!event.target.closest(".user-menu-container")) {
+  // ── Document click (delegates to model for search, keeps user menu local) ──
+  function handleDocumentClick(event: MouseEvent) {
+    const { closeSearch } = model.handleDocumentClick(event);
+    if (!(event.target as Element)?.closest(".user-menu-container")) {
       closeUserMenu();
     }
-    if (!event.target.closest(".global-search-container")) {
-      isSearchFocused = false;
-      clearSearchState();
+    if (closeSearch) {
+      model.isSearchFocused = false;
+      model.clearSearch();
     }
   }
 
-  function handleHamburgerClick(event) {
+  // ── Hamburger ──────────────────────────────────────────────────
+  function handleHamburgerClick(event: MouseEvent) {
     event.stopPropagation();
     toggleMobileSidebar();
   }
 
-  function handleGlobalEnvironmentChange(event) {
-    const nextEnvId = event.currentTarget.value;
-    selectedEnvironmentValue = nextEnvId;
+  // ── Environment selector ───────────────────────────────────────
+  function handleGlobalEnvironmentChange(event: Event) {
+    const nextEnvId = (event.currentTarget as HTMLSelectElement).value;
     setSelectedEnvironment(nextEnvId);
-    if (searchQuery.trim().length >= SEARCH_MIN_LENGTH) {
-      triggerSearch(searchQuery.trim());
+    if (model.searchQuery.trim().length >= 2) {
+      model.triggerSearch(model.searchQuery.trim(), nextEnvId);
     }
   }
 
-  function buildSearchResultSections(
-    dashboardResponse,
-    datasetResponse,
-    tasksResponse,
-    reportsResponse,
-    query,
-  ) {
-    const dashboards = (dashboardResponse?.dashboards || []).slice(
-      0,
-      SEARCH_LIMIT,
-    );
-    const datasets = (datasetResponse?.datasets || []).slice(0, SEARCH_LIMIT);
-    const dashboardItems = dashboards.map((dashboard) => ({
-      key: `dashboard-${dashboard.id}`,
-      type: "dashboard",
-      title: dashboard.title || dashboard.dashboard_title || `#${dashboard.id}`,
-      subtitle: `ID: ${dashboard.id}`,
-      href: `/dashboards/${encodeURIComponent(String(dashboard.slug || dashboard.id))}?env_id=${encodeURIComponent(globalSelectedEnvId)}`,
-    }));
-    const datasetItems = datasets.map((dataset) => ({
-      key: `dataset-${dataset.id}`,
-      type: "dataset",
-      title: dataset.table_name || `#${dataset.id}`,
-      subtitle: dataset.schema || "-",
-      href: `/datasets/${dataset.id}?env_id=${encodeURIComponent(globalSelectedEnvId)}`,
-    }));
-    const q = String(query || "").toLowerCase();
-    const tasks = (tasksResponse || []).slice(0, 30);
-    const taskItems = tasks
-      .filter((task) => {
-        const haystack =
-          `${task?.id || ""} ${task?.plugin_id || ""} ${task?.status || ""}`.toLowerCase();
-        return q && haystack.includes(q);
-      })
-      .slice(0, SEARCH_LIMIT)
-      .map((task) => ({
-        key: `task-${task.id}`,
-        type: "task",
-        title: task.plugin_id || "task",
-        subtitle: `${task.id} · ${task.status || "-"}`,
-        taskId: task.id,
-      }));
-    const reportItems = (reportsResponse?.items || [])
-      .slice(0, SEARCH_LIMIT)
-      .map((report) => ({
-        key: `report-${report.report_id}`,
-        type: "report",
-        title: report.summary || report.report_id,
-        subtitle: `${report.task_type || "-"} · ${report.status || "-"}`,
-        href: "/reports",
-      }));
-
-    const sections = [];
-    if (dashboardItems.length > 0) {
-      sections.push({
-        key: "dashboards",
-        label: $t.nav?.dashboards || "Dashboards",
-        items: dashboardItems,
-      });
-    }
-    if (datasetItems.length > 0) {
-      sections.push({
-        key: "datasets",
-        label: $t.nav?.datasets || "Datasets",
-        items: datasetItems,
-      });
-    }
-    if (taskItems.length > 0) {
-      sections.push({
-        key: "tasks",
-        label: $t.nav?.tasks || "Tasks",
-        items: taskItems,
-      });
-    }
-    if (reportItems.length > 0) {
-      sections.push({
-        key: "reports",
-        label: $t.nav?.reports || "Reports",
-        items: reportItems,
-      });
-    }
-    return sections;
-  }
-
-  async function triggerSearch(query) {
-    const normalizedQuery = String(query || "").trim();
-    if (normalizedQuery.length < SEARCH_MIN_LENGTH || !globalSelectedEnvId) {
-      clearSearchState();
-      return;
-    }
-    isSearchLoading = true;
-    showSearchDropdown = true;
-    try {
-      const [
-        dashboardResponse,
-        datasetResponse,
-        tasksResponse,
-        reportsResponse,
-      ] = await Promise.all([
-        api.getDashboards(globalSelectedEnvId, {
-          search: normalizedQuery,
-          page: 1,
-          page_size: SEARCH_LIMIT,
-        }),
-        api.getDatasets(globalSelectedEnvId, {
-          search: normalizedQuery,
-          page: 1,
-          page_size: SEARCH_LIMIT,
-        }),
-        api.getTasks({ limit: 30, offset: 0, search: normalizedQuery }),
-        getReports({
-          page: 1,
-          page_size: SEARCH_LIMIT,
-          search: normalizedQuery,
-          sort_by: "updated_at",
-          sort_order: "desc",
-        }),
-      ]);
-      groupedSearchResults = buildSearchResultSections(
-        dashboardResponse,
-        datasetResponse,
-        tasksResponse,
-        reportsResponse,
-        normalizedQuery,
-      );
-    } catch (error) {
-      log("TopNavbar", "EXPLORE", "Global search failed", { query: normalizedQuery }, error instanceof Error ? error.message : String(error));
-      groupedSearchResults = [];
-    } finally {
-      isSearchLoading = false;
-    }
-  }
-
-  function handleSearchInput(event) {
-    searchQuery = event.target.value;
-    if (searchTimer) {
-      clearTimeout(searchTimer);
-    }
-    searchTimer = setTimeout(() => {
-      triggerSearch(searchQuery);
-    }, SEARCH_DEBOUNCE_MS);
-  }
-
-  async function openSearchResult(item) {
-    clearSearchState();
-    searchQuery = "";
-    isSearchFocused = false;
-    if (item.type === "task" && item.taskId) {
-      openDrawerForTask(item.taskId);
-      return;
-    }
-    if (item.href) {
-      await goto(item.href);
-    }
-  }
-
-  async function handleSearchKeydown(event) {
-    if (event.key === "Escape") {
-      clearSearchState();
-      searchQuery = "";
-      isSearchFocused = false;
-      return;
-    }
-    const firstItem = groupedSearchResults[0]?.items?.[0];
-    if (event.key === "Enter" && firstItem) {
+  // ── Search keyboard (Escape/Enter) ─────────────────────────────
+  async function handleSearchKeydown(event: KeyboardEvent) {
+    if (await model.handleSearchKeydown(event.key, globalSelectedEnvId)) {
       event.preventDefault();
-      await openSearchResult(firstItem);
     }
   }
 
+  // ── Lifecycle ──────────────────────────────────────────────────
   onMount(() => {
     void initializeEnvironmentContext();
-    void hydrateTaskDrawerPreference();
+    void model.hydrateTaskDrawerPreference();
     if (typeof document !== "undefined") {
       document.addEventListener("click", handleDocumentClick);
     }
     return () => {
-      if (searchTimer) {
-        clearTimeout(searchTimer);
-      }
+      model.destroy();
       if (typeof document !== "undefined") {
         document.removeEventListener("click", handleDocumentClick);
       }
@@ -388,12 +172,11 @@
 </script>
 
 <nav
-  class="fixed left-0 right-0 top-0 z-40 flex h-16 max-w-full items-center justify-between overflow-hidden border-b border-border bg-surface-card px-3 shadow-sm sm:px-4
+  class="fixed left-0 right-0 top-0 z-40 flex h-16 max-w-full items-center justify-between overflow-visible border-b border-border bg-surface-card px-3 shadow-sm sm:px-4
     {isExpanded ? 'md:left-[240px]' : 'md:left-16'}"
 >
   <!-- Left section: Hamburger (mobile) + Logo -->
   <div class="flex min-w-0 items-center gap-2">
-    <!-- Hamburger Menu (mobile only) -->
     <button
       class="rounded-lg p-2 text-text-muted transition-colors hover:bg-surface-muted md:hidden"
       onclick={handleHamburgerClick}
@@ -408,7 +191,7 @@
       class="flex min-w-0 items-center text-xl font-bold text-text transition-colors hover:text-primary"
     >
       <span
-        class="mr-2 inline-flex h-9 w-9 items-center justify-center rounded-xl bg-gradient-to-br from-sky-500 via-cyan-500 to-indigo-600 text-white shadow-sm"
+        class="mr-2 inline-flex h-9 w-9 items-center justify-center rounded-xl bg-gradient-to-br from-brand-gradient-from via-brand-gradient-via to-brand-gradient-to text-white shadow-sm"
       >
         <Icon name="layers" size={18} strokeWidth={2.1} />
       </span>
@@ -417,46 +200,44 @@
   </div>
 
   <!-- Global search -->
-  <div
-    class="global-search-container relative flex-1 max-w-xl mx-4 hidden md:block"
-  >
+  <div class="global-search-container relative flex-1 max-w-xl mx-4 hidden md:block">
     <input
       id="global-search"
       name="global_search"
       aria-label={$t.common.search}
       type="text"
       class="w-full px-4 py-2 bg-surface-muted rounded-lg focus:outline-none focus:ring-2 focus:ring-primary-ring transition-all
-        {isSearchFocused ? 'bg-surface-card border border-primary-ring' : ''}"
+        {model.isSearchFocused ? 'bg-surface-card border border-primary-ring' : ''}"
       placeholder={$t.common.search}
-      value={searchQuery}
-      oninput={handleSearchInput}
-      onfocus={handleSearchFocus}
+      value={model.searchQuery}
+      oninput={(e) => model.handleSearchInput(e.currentTarget.value)}
+      onfocus={() => model.handleSearchFocus()}
       onkeydown={handleSearchKeydown}
     />
-    {#if showSearchDropdown}
+    {#if model.showSearchDropdown}
       <div
         class="absolute left-0 right-0 top-12 z-50 rounded-lg border border-border bg-surface-card shadow-lg"
       >
-        {#if isSearchLoading}
+        {#if model.isSearchLoading}
           <div class="px-4 py-3 text-sm text-text-muted">
             {$t.common?.loading || "Loading..."}
           </div>
-        {:else if groupedSearchResults.length === 0}
+        {:else if model.groupedSearchResults.length === 0}
           <div class="px-4 py-3 text-sm text-text-muted">
             {$t.common?.not_found || "No results found"}
           </div>
         {:else}
-          {#each groupedSearchResults as section}
+          {#each model.groupedSearchResults as section (section.key)}
             <div class="border-b border-border last:border-b-0">
               <div
                 class="px-4 py-2 text-xs font-semibold uppercase tracking-wide text-text-muted"
               >
-                {section.label}
+                {$t.nav?.[section.labelKey] || section.labelKey}
               </div>
-              {#each section.items as result}
+              {#each section.items as result (result.key)}
                 <button
                   class="flex w-full items-center justify-between px-4 py-2 text-left hover:bg-surface-page"
-                  onclick={() => openSearchResult(result)}
+                  onclick={() => model.openSearchResult(result)}
                 >
                   <div class="min-w-0">
                     <div class="truncate text-sm font-medium text-text">
@@ -485,24 +266,21 @@
           class="h-9 rounded-lg border px-3 text-sm font-medium focus:outline-none focus:ring-2
             {isProdContext
             ? 'border-destructive-ring bg-destructive-light text-destructive focus:ring-destructive-ring'
-            : 'border-border-strong bg-surface-card text-text focus:ring-sky-200'}"
+            : 'border-border-strong bg-surface-card text-text focus:ring-primary-ring-light'}"
           bind:value={selectedEnvironmentValue}
           onchange={handleGlobalEnvironmentChange}
           aria-label={$t.dashboard?.environment || "Environment"}
           title={$t.dashboard?.environment || "Environment"}
         >
-          {#each globalEnvironments as env}
+          {#each globalEnvironments as env (env.id)}
             <option value={env.id}>
               {env.name}{(String(env.stage || "").toUpperCase() === "PROD" || env.is_production) ? " [PROD]" : ""}
             </option>
           {/each}
         </select>
-
       </div>
     {/if}
 
-    <LanguageSwitcher />
-
     <!-- Assistant -->
     <button
       class="flex items-center gap-1.5 rounded-lg border border-border-strong bg-surface-card px-3 py-1.5 text-xs font-medium text-text transition hover:bg-primary hover:text-white hover:border-primary"
@@ -511,7 +289,7 @@
       title={$t.assistant?.title}
     >
       <Icon name="aiAssistant" size={16} />
-      <span>{$t.assistant?.assistant || "Ассистент"}</span>
+      <span>{$t.assistant.assistant}</span>
     </button>
 
     <!-- Activity Indicator -->
@@ -539,7 +317,7 @@
         class="w-8 h-8 rounded-full bg-primary text-white flex items-center justify-center cursor-pointer hover:bg-primary-hover transition-colors"
         onclick={toggleUserMenu}
         onkeydown={(e) =>
-          (e.key === "Enter" || e.key === " ") && toggleUserMenu(e)}
+          (e.key === "Enter" || e.key === " ") && toggleUserMenu()}
         role="button"
         tabindex="0"
         aria-label={$t.common?.user_menu}
@@ -563,15 +341,30 @@
           <strong>{user?.username || $t.common?.user}</strong>
         </div>
         <div class="border-t border-border my-1"></div>
+        <div
+          class="px-4 py-2 text-sm text-text hover:bg-surface-muted cursor-pointer"
+          onclick={() => {
+            closeUserMenu();
+            window.location.href = ROUTES.profile();
+          }}
+          onkeydown={(e) =>
+            (e.key === "Enter" || e.key === " ") &&
+            (closeUserMenu(), window.location.href = ROUTES.profile())}
+          role="button"
+          tabindex="0"
+        >
+          {$t.nav?.profile || "Profile"}
+        </div>
         {#if canOpenSettings}
           <div
             class="px-4 py-2 text-sm text-text hover:bg-surface-muted cursor-pointer"
             onclick={() => {
+              closeUserMenu();
               window.location.href = ROUTES.settings.general();
             }}
             onkeydown={(e) =>
               (e.key === "Enter" || e.key === " ") &&
-              (window.location.href = ROUTES.settings.general())}
+              (closeUserMenu(), window.location.href = ROUTES.settings.general())}
             role="button"
             tabindex="0"
           >
diff --git a/frontend/src/lib/models/TopNavbarModel.svelte.ts b/frontend/src/lib/models/TopNavbarModel.svelte.ts
new file mode 100644
index 000000000..f2d5e7b48
--- /dev/null
+++ b/frontend/src/lib/models/TopNavbarModel.svelte.ts
@@ -0,0 +1,303 @@
+// #region TopNavbar.Model [C:4] [TYPE Model] [SEMANTICS navbar,search,model,topnav]
+// @defgroup TopNavbar Screen Model for the unified top navigation bar search and drawer preference hydration.
+// @LAYER Store
+// @PRE Environment context store is loaded before search is triggered.
+// @INVARIANT Search debounce at 250ms. Min query length 2 characters. Max 5 results per section.
+// @INVARIANT ClearSearch resets all search state atoms to defaults.
+// @STATE searchQuery, isSearchFocused, showSearchDropdown, isSearchLoading, groupedSearchResults
+// @ACTION triggerSearch(query, envId), handleSearchInput(value), handleSearchFocus, handleSearchKeydown(key), openSearchResult(item), handleDocumentClick(event), clearSearch, hydrateTaskDrawerPreference, destroy
+// @RELATION CALLS -> [getDashboards]
+// @RELATION CALLS -> [getDatasets]
+// @RELATION CALLS -> [getTasks]
+// @RELATION CALLS -> [getProfilePreferences]
+// @RELATION CALLS -> [getReports]
+// @RELATION DISPATCHES -> [EXT:frontend:taskDrawerStore]
+// @DATA_CONTRACT SearchQuery:string × EnvId:string → SearchSection[] | ProfilePreferences → void
+// @POST Search results grouped by section (dashboards, datasets, tasks, reports). Dropdown stays open while results load.
+// @SIDE_EFFECT Fetch API (dashboards, datasets, tasks, reports), localStorage I/O via setTaskDrawerAutoOpenPreference.
+// @RATIONALE Search logic extracted from TopNavbar component (605 lines → ~300 lines) to satisfy INV_7 (module < 400 LOC) and ATTN_4 (contract ≤ 150 lines in sliding window). The original inline architecture scattered search state across 7 reactive atoms and 8 functions inside a single 605-line component — the model could not physically see the full contract under CSA/HCA compression. Model-first extraction puts dense #region anchor on line 1 for maximum first-line density, dot-separated hierarchical ID for HCA survival, and groups all search state into one unit that fits the sliding window.
+// @REJECTED Extracting user menu, environment selector, and activity indicator into submodels was rejected — each is ≤ 3 store-derived values with simple toggle logic, extract overhead exceeds benefit. Inline $state for those three concerns is the right call per Model Decomposition Gate: they are local UI state without cross-widget invariants. Full decomposition into 3 submodels was rejected as premature (each submodel would be < 30 lines).
+
+import { goto } from "$app/navigation";
+import { log } from "$lib/cot-logger";
+import { api } from "$lib/api.js";
+import { getReports } from "$lib/api/reports.js";
+import {
+	openDrawerForTask,
+	setTaskDrawerAutoOpenPreference,
+} from "$lib/stores/taskDrawer.svelte.js";
+import type { Task, TaskStatus } from "$types/models";
+import type { ReportCollection } from "$types/reports";
+
+// ── Type definitions ─────────────────────────────────────────────
+
+interface SearchResultItem {
+	key: string;
+	type: string;
+	title: string;
+	subtitle: string;
+	href?: string;
+	taskId?: string;
+}
+
+interface SearchSection {
+	key: string;
+	labelKey: string; // i18n key resolved in template: $t.nav?.[section.labelKey]
+	items: SearchResultItem[];
+}
+
+/** Dashboard shape returned by GET /dashboards (subset used by search). */
+interface DashboardSearchResult {
+	id: number | string;
+	title?: string;
+	dashboard_title?: string;
+	slug?: string;
+}
+
+/** Dataset shape returned by GET /datasets (subset used by search). */
+interface DatasetSearchResult {
+	id: number | string;
+	table_name?: string;
+	schema?: string;
+}
+
+/** Task enriched with fields used for client-side filtering. */
+interface TaskSearchResult extends Task {
+	plugin_id?: string;
+	status?: TaskStatus;
+}
+
+interface DashboardsResponse {
+	dashboards?: DashboardSearchResult[];
+}
+
+interface DatasetsResponse {
+	datasets?: DatasetSearchResult[];
+}
+
+// ── Constants ────────────────────────────────────────────────────
+
+const SEARCH_DEBOUNCE_MS = 250;
+const SEARCH_MIN_LENGTH = 2;
+const SEARCH_LIMIT = 5;
+
+// ── Model ────────────────────────────────────────────────────────
+
+export class TopNavbarModel {
+	// ── Atoms ─────────────────────────────────────────────────────
+	searchQuery: string = $state("");
+	isSearchFocused: boolean = $state(false);
+	showSearchDropdown: boolean = $state(false);
+	isSearchLoading: boolean = $state(false);
+	groupedSearchResults: SearchSection[] = $state([]);
+
+	// ── Internal (non-reactive) ───────────────────────────────────
+	private searchTimer: ReturnType<typeof setTimeout> | null = null;
+
+	// ── Public actions ────────────────────────────────────────────
+
+	handleSearchInput(value: string): void {
+		this.searchQuery = value;
+		if (this.searchTimer) {
+			clearTimeout(this.searchTimer);
+		}
+		this.searchTimer = setTimeout(() => {
+			this._triggerSearch(this.searchQuery);
+		}, SEARCH_DEBOUNCE_MS);
+	}
+
+	handleSearchFocus(): void {
+		this.isSearchFocused = true;
+		this.showSearchDropdown = this.groupedSearchResults.length > 0;
+	}
+
+	clearSearch(): void {
+		this.showSearchDropdown = false;
+		this.isSearchLoading = false;
+		this.groupedSearchResults = [];
+	}
+
+	async handleSearchKeydown(key: string, envId: string): Promise<boolean> {
+		if (key === "Escape") {
+			this.clearSearch();
+			this.searchQuery = "";
+			this.isSearchFocused = false;
+			return true;
+		}
+		const firstItem = this.groupedSearchResults[0]?.items?.[0];
+		if (key === "Enter" && firstItem) {
+			await this.openSearchResult(firstItem);
+			return true;
+		}
+		return false;
+	}
+
+	async openSearchResult(item: SearchResultItem): Promise<void> {
+		this.clearSearch();
+		this.searchQuery = "";
+		this.isSearchFocused = false;
+		if (item.type === "task" && item.taskId) {
+			openDrawerForTask(item.taskId);
+			return;
+		}
+		if (item.href) {
+			await goto(item.href);
+		}
+	}
+
+	async triggerSearch(query: string, envId: string): Promise<void> {
+		this.searchQuery = query;
+		await this._triggerSearch(query, envId);
+	}
+
+	handleDocumentClick(event: MouseEvent): { closeUserMenu: boolean; closeSearch: boolean } {
+		const result = { closeUserMenu: false, closeSearch: false };
+		if (!(event.target as Element)?.closest(".user-menu-container")) {
+			result.closeUserMenu = true;
+		}
+		if (!(event.target as Element)?.closest(".global-search-container")) {
+			result.closeSearch = true;
+		}
+		return result;
+	}
+
+	async hydrateTaskDrawerPreference(): Promise<void> {
+		try {
+			const response = await api.getProfilePreferences<{ preference?: { auto_open_task_drawer?: boolean } }>();
+			const autoOpenTaskDrawer = response?.preference?.auto_open_task_drawer;
+			setTaskDrawerAutoOpenPreference(autoOpenTaskDrawer !== false);
+		} catch (error) {
+			log("TopNavbarModel", "EXPLORE", "Failed to hydrate task drawer preference", {}, error instanceof Error ? error.message : String(error));
+		}
+	}
+
+	destroy(): void {
+		if (this.searchTimer) {
+			clearTimeout(this.searchTimer);
+			this.searchTimer = null;
+		}
+	}
+
+	// ── Private ───────────────────────────────────────────────────
+
+	private async _triggerSearch(query: string, envId?: string): Promise<void> {
+		const normalizedQuery = String(query || "").trim();
+		if (normalizedQuery.length < SEARCH_MIN_LENGTH || !envId) {
+			this.clearSearch();
+			return;
+		}
+		this.isSearchLoading = true;
+		this.showSearchDropdown = true;
+		try {
+			const [
+				dashboardResponse,
+				datasetResponse,
+				tasksResponse,
+				reportsResponse,
+			] = await Promise.all([
+				api.getDashboards(envId, {
+					search: normalizedQuery,
+					page: 1,
+					page_size: SEARCH_LIMIT,
+				}),
+				api.getDatasets(envId, {
+					search: normalizedQuery,
+					page: 1,
+					page_size: SEARCH_LIMIT,
+				}),
+				api.getTasks({ limit: 30, offset: 0, search: normalizedQuery }),
+				getReports({
+					page: 1,
+					page_size: SEARCH_LIMIT,
+					search: normalizedQuery,
+					sort_by: "updated_at",
+					sort_order: "desc",
+				}),
+			]);
+			this.groupedSearchResults = this._buildSections(
+				dashboardResponse,
+				datasetResponse,
+				tasksResponse,
+				reportsResponse,
+				normalizedQuery,
+				envId,
+			);
+		} catch (error) {
+			log("TopNavbarModel", "EXPLORE", "Global search failed", { query: normalizedQuery }, error instanceof Error ? error.message : String(error));
+			this.groupedSearchResults = [];
+		} finally {
+			this.isSearchLoading = false;
+		}
+	}
+
+	private _buildSections(
+		dashboardResponse: DashboardsResponse,
+		datasetResponse: DatasetsResponse,
+		tasksResponse: TaskSearchResult[],
+		reportsResponse: ReportCollection,
+		query: string,
+		envId: string,
+	): SearchSection[] {
+		const dashboards = (dashboardResponse.dashboards || []).slice(0, SEARCH_LIMIT);
+		const datasets = (datasetResponse.datasets || []).slice(0, SEARCH_LIMIT);
+
+		const dashboardItems: SearchResultItem[] = dashboards.map((dashboard) => ({
+			key: `dashboard-${dashboard.id}`,
+			type: "dashboard",
+			title: dashboard.title || dashboard.dashboard_title || `#${dashboard.id}`,
+			subtitle: `ID: ${dashboard.id}`,
+			href: `/dashboards/${encodeURIComponent(String(dashboard.slug || dashboard.id))}?env_id=${encodeURIComponent(envId)}`,
+		}));
+
+		const datasetItems: SearchResultItem[] = datasets.map((dataset) => ({
+			key: `dataset-${dataset.id}`,
+			type: "dataset",
+			title: dataset.table_name || `#${dataset.id}`,
+			subtitle: dataset.schema || "-",
+			href: `/datasets/${dataset.id}?env_id=${encodeURIComponent(envId)}`,
+		}));
+
+		const q = String(query || "").toLowerCase();
+		const tasks = (tasksResponse || []).slice(0, 30);
+		const taskItems: SearchResultItem[] = tasks
+			.filter((task) => {
+				const haystack = `${task.id || ""} ${task.plugin_id || ""} ${task.status || ""}`.toLowerCase();
+				return q && haystack.includes(q);
+			})
+			.slice(0, SEARCH_LIMIT)
+			.map((task) => ({
+				key: `task-${task.id}`,
+				type: "task",
+				title: task.plugin_id || "task",
+				subtitle: `${task.id} · ${task.status || "-"}`,
+				taskId: task.id,
+			}));
+
+		const reportItems: SearchResultItem[] = (reportsResponse.items || [])
+			.slice(0, SEARCH_LIMIT)
+			.map((report) => ({
+				key: `report-${report.report_id}`,
+				type: "report",
+				title: report.summary || report.report_id,
+				subtitle: `${report.task_type || "-"} · ${report.status || "-"}`,
+				href: "/reports",
+			}));
+
+		// Section labelKey resolves via $t.nav?.[labelKey] in the component template.
+		const sections: SearchSection[] = [];
+		if (dashboardItems.length > 0) {
+			sections.push({ key: "dashboards", labelKey: "dashboards", items: dashboardItems });
+		}
+		if (datasetItems.length > 0) {
+			sections.push({ key: "datasets", labelKey: "datasets", items: datasetItems });
+		}
+		if (taskItems.length > 0) {
+			sections.push({ key: "tasks", labelKey: "tasks", items: taskItems });
+		}
+		if (reportItems.length > 0) {
+			sections.push({ key: "reports", labelKey: "reports", items: reportItems });
+		}
+		return sections;
+	}
+}
+// #endregion TopNavbar.Model
diff --git a/frontend/tailwind.config.js b/frontend/tailwind.config.js
index 4dd814207..05a5a9d18 100755
--- a/frontend/tailwind.config.js
+++ b/frontend/tailwind.config.js
@@ -12,6 +12,7 @@ export default {
           DEFAULT: '#2563eb', // blue-600
           hover: '#1d4ed8',   // blue-700
           ring: '#3b82f6',    // blue-500
+          'ring-light': '#bae6fd', // sky-200 — focus ring for non-critical controls
           light: '#eff6ff',   // blue-50
         },
         secondary: {
@@ -96,6 +97,12 @@ export default {
           git: '#fb923c',
           system: '#38bdf8',
         },
+        // ── Brand identity ──────────────────────────────────────
+        brand: {
+          'gradient-from': '#0ea5e9',  // sky-500
+          'gradient-via': '#06b6d4',   // cyan-500
+          'gradient-to': '#4f46e5',    // indigo-600
+        },
         // ── Category gradient tokens (sidebar/breadcrumb icons) ──
         category: {
           dashboards:   { from: '#e0f2fe', to: '#bae6fd', text: '#0369a1', ring: '#7dd3fc' },   // sky