diff --git a/package.json b/package.json
index 6695659c..8f0615e0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "betterseqtaplus",
-  "version": "3.6.5",
+  "version": "3.6.6",
   "type": "module",
   "description": "Enhance SEQTA Learn's usability and aesthetics! A fork of BetterSEQTA to continue development and add heaps more features!",
   "browserslist": "> 0.5%, last 2 versions, not dead",
diff --git a/src/background.ts b/src/background.ts
index b98b5514..074a4138 100644
--- a/src/background.ts
+++ b/src/background.ts
@@ -551,6 +551,76 @@ async function migrateGlobalSearchDefaultsFor365Upgrade(
   }
 }
 
+/** One-time reset for 3.6.6: re-enable Theme of the Month for existing users. */
+const THEME_OF_THE_MONTH_RESET_VERSION = "3.6.6";
+
+async function resetThemeOfTheMonthDisabledFor366Upgrade(
+  previousVersion: string,
+): Promise<void> {
+  try {
+    const currRaw = browser.runtime.getManifest().version;
+    const prev = semver.coerce(previousVersion);
+    const curr = semver.coerce(currRaw);
+    if (
+      prev == null ||
+      curr == null ||
+      semver.lt(curr, THEME_OF_THE_MONTH_RESET_VERSION) ||
+      !semver.lt(prev, THEME_OF_THE_MONTH_RESET_VERSION)
+    ) {
+      return;
+    }
+
+    await browser.storage.local.set({
+      themeOfTheMonthDisabled: false,
+      themeOfTheMonthLastSeenId: undefined,
+    });
+
+    console.info(
+      `[BetterSEQTA+] Migration ${THEME_OF_THE_MONTH_RESET_VERSION}: Theme of the Month re-enabled (from ${previousVersion}).`,
+    );
+  } catch (e) {
+    console.warn(
+      "[BetterSEQTA+] Theme of the Month 3.6.6 reset migration failed:",
+      e,
+    );
+  }
+}
+
+/** 3.7.0: Close no longer marks entries seen — clear legacy dismissal keys. */
+const THEME_OF_THE_MONTH_RELOAD_VERSION = "3.7.0";
+
+async function resetThemeOfTheMonthDismissalFor370Upgrade(
+  previousVersion: string,
+): Promise<void> {
+  try {
+    const currRaw = browser.runtime.getManifest().version;
+    const prev = semver.coerce(previousVersion);
+    const curr = semver.coerce(currRaw);
+    if (
+      prev == null ||
+      curr == null ||
+      semver.lt(curr, THEME_OF_THE_MONTH_RELOAD_VERSION) ||
+      !semver.lt(prev, THEME_OF_THE_MONTH_RELOAD_VERSION)
+    ) {
+      return;
+    }
+
+    await browser.storage.local.set({
+      themeOfTheMonthLastSeenId: undefined,
+      themeOfTheMonthDismissedMonth: undefined,
+    });
+
+    console.info(
+      `[BetterSEQTA+] Migration ${THEME_OF_THE_MONTH_RELOAD_VERSION}: Theme of the Month shows again until dismissed for the month (from ${previousVersion}).`,
+    );
+  } catch (e) {
+    console.warn(
+      "[BetterSEQTA+] Theme of the Month 3.7.0 dismissal migration failed:",
+      e,
+    );
+  }
+}
+
 browser.runtime.onInstalled.addListener(function (event) {
   browser.storage.local.remove(["justupdated"]);
   browser.storage.local.remove(["data"]);
@@ -561,6 +631,8 @@ browser.runtime.onInstalled.addListener(function (event) {
 
   if (event.reason === "update" && event.previousVersion) {
     void migrateGlobalSearchDefaultsFor365Upgrade(event.previousVersion);
+    void resetThemeOfTheMonthDisabledFor366Upgrade(event.previousVersion);
+    void resetThemeOfTheMonthDismissalFor370Upgrade(event.previousVersion);
   }
 });
 
diff --git a/src/css/injected.scss b/src/css/injected.scss
index 57f7fc64..a1580330 100644
--- a/src/css/injected.scss
+++ b/src/css/injected.scss
@@ -455,6 +455,58 @@ ul.magicDelete > li.deleting {
   top: 71.5px;
   margin-top: -2px;
 }
+
+/* Drill-in stack: only the current list + folder header stay clickable.
+   Class is toggled by updateSidebarAccessibility (never touches aria-hidden). */
+#menu .bsplus-sidebar-offscreen,
+#menu .bsplus-sidebar-offscreen * {
+  pointer-events: none !important;
+  user-select: none !important;
+}
+
+#menu > ul > .bsplus-sidebar-offscreen:not(.hasChildren.active) {
+  position: absolute !important;
+  left: -10000px !important;
+  width: 1px !important;
+  height: 1px !important;
+  margin: 0 !important;
+  padding: 0 !important;
+  overflow: hidden !important;
+  clip: rect(0, 0, 0, 0) !important;
+  opacity: 0 !important;
+}
+
+#menu .sub .bsplus-sidebar-offscreen:not(.hasChildren.active) {
+  visibility: hidden !important;
+  position: absolute !important;
+  left: -10000px !important;
+  width: 1px !important;
+  height: 1px !important;
+  margin: 0 !important;
+  padding: 0 !important;
+  opacity: 0 !important;
+}
+
+/* Only the frontmost open .sub panel receives pointer events */
+#menu .sub {
+  pointer-events: none;
+}
+
+#menu li.hasChildren.active > .sub {
+  pointer-events: auto;
+}
+
+#menu li.hasChildren.active > .sub:has(.hasChildren.active) {
+  pointer-events: none !important;
+}
+
+#menu li.hasChildren.active .hasChildren.active > .sub {
+  pointer-events: auto !important;
+}
+
+#menu:has(> ul > li.hasChildren.active) > ul > li:not(.hasChildren.active) {
+  pointer-events: none !important;
+}
 #menu section > label {
   align-items: center;
   box-sizing: border-box;
@@ -2326,6 +2378,10 @@ blurred {
   height: 64px;
   cursor: pointer;
 }
+/* While a drill-in submenu is open, don't steal clicks meant for folder rows. */
+#menu:has(li.hasChildren.active) > .icon-cover {
+  pointer-events: none;
+}
 .uiSlidePane > .pane > .header button {
   color: var(--text-color) !important;
 }
@@ -3753,20 +3809,77 @@ div.day-empty {
   pointer-events: none;
   animation: themeOfTheMonthCardOut 0.18s ease-in forwards;
 }
-.themeOfTheMonthCardClose {
-  position: absolute !important;
-  top: 4px !important;
-  right: 4px !important;
-  z-index: 2;
-  width: 32px;
-  height: 32px;
-  border: 1px solid rgba(255, 255, 255, 0.22);
-  border-radius: 16px !important;
-  background: rgba(0, 0, 0, 0.42);
-  color: white;
+.themeOfTheMonthCardConfirm {
+  position: absolute;
+  inset: 0;
+  z-index: 4;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 16px;
+  border-radius: inherit;
+  background: color-mix(in srgb, var(--background-primary) 88%, transparent);
+  backdrop-filter: blur(8px);
+  -webkit-backdrop-filter: blur(8px);
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity 0.16s ease;
+}
+.themeOfTheMonthCardConfirm[hidden] {
+  display: none;
+}
+.themeOfTheMonthCardConfirmVisible {
+  opacity: 1;
+  pointer-events: auto;
+}
+.themeOfTheMonthCardConfirmInner {
+  width: 100%;
+  text-align: center;
+}
+.themeOfTheMonthCardConfirmInner h3 {
+  margin: 0 0 6px;
+  font-size: 1rem;
+  line-height: 1.2;
+}
+.themeOfTheMonthCardConfirmInner p {
+  margin: 0 0 14px;
+  font-size: 0.86rem;
+  line-height: 1.4;
+  color: color-mix(in srgb, var(--text-primary) 78%, transparent);
+}
+.themeOfTheMonthCardConfirmActions {
+  display: flex;
+  flex-wrap: wrap;
+  justify-content: center;
+  gap: 8px;
+}
+.themeOfTheMonthCardConfirmCancel,
+.themeOfTheMonthCardConfirmAccept {
+  appearance: none;
+  border: none;
   cursor: pointer;
-  font-size: 1.35rem;
-  line-height: 1;
+  border-radius: 9999px;
+  padding: 0.5rem 0.85rem;
+  font-size: 0.84rem;
+  font-weight: 700;
+  transition: transform 0.15s ease, filter 0.15s ease, background 0.15s ease;
+}
+.themeOfTheMonthCardConfirmCancel {
+  background: color-mix(in srgb, var(--text-primary) 10%, transparent);
+  color: var(--text-primary);
+}
+.themeOfTheMonthCardConfirmAccept {
+  background: var(--better-pri, #6366f1);
+  color: white;
+}
+.themeOfTheMonthCardConfirmCancel:hover,
+.themeOfTheMonthCardConfirmAccept:hover {
+  filter: brightness(1.08);
+  transform: translateY(-1px);
+}
+.themeOfTheMonthCardConfirmCancel:active,
+.themeOfTheMonthCardConfirmAccept:active {
+  transform: translateY(0);
 }
 .themeOfTheMonthCardImage {
   display: block;
@@ -3805,11 +3918,34 @@ div.day-empty {
 .themeOfTheMonthCardActions {
   display: flex;
   flex-wrap: wrap;
-  justify-content: flex-end;
-  gap: 8px;
+  align-items: center;
+  justify-content: space-between;
+  gap: 10px;
+}
+.themeOfTheMonthCardActionsStart {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+}
+.themeOfTheMonthCardActionsEnd {
+  display: inline-flex;
+  flex-wrap: nowrap;
+  align-items: stretch;
+  margin-left: auto;
+  padding: 3px;
+  gap: 0;
+  overflow: hidden;
+  border-radius: 9999px;
+  background: color-mix(
+    in srgb,
+    var(--background-secondary, var(--text-primary)) 28%,
+    var(--background-primary)
+  );
+  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--text-primary) 8%, transparent);
 }
 .themeOfTheMonthCardPrimary,
-.themeOfTheMonthCardSecondary {
+.themeOfTheMonthCardSecondary,
+.themeOfTheMonthCardDontShow {
   appearance: none;
   border: none;
   cursor: pointer;
@@ -3817,23 +3953,49 @@ div.day-empty {
   padding: 0.58rem 0.9rem;
   font-size: 0.86rem;
   font-weight: 700;
-  transition: transform 0.15s ease, filter 0.15s ease, background 0.15s ease;
+  transition: background 0.15s ease, color 0.15s ease;
 }
 .themeOfTheMonthCardPrimary {
   background: var(--better-pri, #6366f1);
   color: white;
 }
-.themeOfTheMonthCardSecondary {
-  background: color-mix(in srgb, var(--text-primary) 10%, transparent);
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardSecondary,
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardDontShow {
+  padding: 0.5rem 0.8rem;
+  font-size: 0.8rem;
+  font-weight: 600;
+  border: none !important;
+  border-radius: 9999px !important;
+  background: transparent !important;
+  box-shadow: none !important;
+  filter: none !important;
+  transform: none !important;
+}
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardSecondary {
   color: var(--text-primary);
 }
-.themeOfTheMonthCardPrimary:hover,
-.themeOfTheMonthCardSecondary:hover {
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardDontShow {
+  color: color-mix(in srgb, var(--text-primary) 58%, transparent);
+}
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardSecondary:hover,
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardSecondary:focus-visible,
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardDontShow:hover,
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardDontShow:focus-visible {
+  background: color-mix(in srgb, var(--text-primary) 10%, transparent) !important;
+  border-radius: 9999px !important;
+  filter: none !important;
+  transform: none !important;
+}
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardSecondary:active,
+#theme-of-the-month-card .themeOfTheMonthCardActionsEnd .themeOfTheMonthCardDontShow:active {
+  background: color-mix(in srgb, var(--text-primary) 14%, transparent) !important;
+  border-radius: 9999px !important;
+}
+.themeOfTheMonthCardPrimary:hover {
   filter: brightness(1.08);
   transform: translateY(-1px);
 }
-.themeOfTheMonthCardPrimary:active,
-.themeOfTheMonthCardSecondary:active {
+.themeOfTheMonthCardPrimary:active {
   transform: translateY(0);
 }
 @keyframes themeOfTheMonthCardIn {
diff --git a/src/interface/pages/settings/general.svelte b/src/interface/pages/settings/general.svelte
index 7bc7ecc9..6140c02f 100644
--- a/src/interface/pages/settings/general.svelte
+++ b/src/interface/pages/settings/general.svelte
@@ -423,6 +423,18 @@
           {/each}
         {/if}
       </div>
+      {#if plugin.pluginId === 'global-search'}
+        {@render Setting({
+          title: "Theme of the Month",
+          description: "Show the monthly featured theme popup when a new entry is available",
+          id: 15,
+          Component: Switch,
+          props: {
+            state: !($settingsState.themeOfTheMonthDisabled ?? false),
+            onChange: (isOn: boolean) => settingsState.themeOfTheMonthDisabled = !isOn
+          }
+        })}
+      {/if}
   </div>
   {/each}
 
diff --git a/src/plugins/built-in/themes/theme-manager.ts b/src/plugins/built-in/themes/theme-manager.ts
index ccaeddf5..492315df 100644
--- a/src/plugins/built-in/themes/theme-manager.ts
+++ b/src/plugins/built-in/themes/theme-manager.ts
@@ -17,6 +17,15 @@ import {
   clearCustomThemeAdaptiveCssVariables,
   setCustomThemeAdaptiveCssVariables,
 } from "@/seqta/ui/colors/customThemeAdaptiveBindings";
+import {
+  clearThemeRuntime,
+  injectThemeDom,
+  runThemeScript,
+  type ThemeDomSpec,
+  type ThemeScriptSpec,
+  validateThemeDom,
+  validateThemeScript,
+} from "./theme-runtime";
 
 type ThemeContent = {
   id: string;
@@ -31,6 +40,8 @@ type ThemeContent = {
   forceDark?: boolean;
   adaptiveCssVariables?: string[];
   images?: { id: string; variableName: string; data: string }[]; // data: base64
+  themeScript?: ThemeScriptSpec;
+  themeDom?: ThemeDomSpec;
 };
 
 export type InstallThemeMeta = {
@@ -53,6 +64,7 @@ export class ThemeManager {
   private imageUrlCache: Map<string, string> = new Map();
   private lastTransitionPoint: { x: number; y: number } = { x: 0, y: 0 };
   private storeUpdateCheckRunning = false;
+  private headObserver: MutationObserver | null = null;
 
   private constructor() {
     console.debug("[ThemeManager] Initializing...");
@@ -307,6 +319,13 @@ export class ThemeManager {
   private async applyTheme(theme: CustomTheme): Promise<void> {
     console.debug("[ThemeManager] Applying theme:", theme.name);
     try {
+      // Run the theme script BEFORE injecting CustomCSS so any state the
+      // script publishes (e.g. `data-city-state` and `--city-sky-color` for
+      // Noir City) is already on <html> when the new CSS rules paint.
+      // Otherwise the CSS lands with var() unresolved and the page flashes
+      // its previous state before snapping to the right colour.
+      runThemeScript(theme.themeScript);
+
       // Apply custom CSS
       if (theme.CustomCSS) {
         console.debug("[ThemeManager] Applying custom CSS");
@@ -348,6 +367,8 @@ export class ThemeManager {
       }
 
       setCustomThemeAdaptiveCssVariables(theme.adaptiveCssVariables ?? []);
+
+      injectThemeDom(theme.themeDom);
     } catch (error) {
       console.error("[ThemeManager] Error applying theme:", error);
     }
@@ -379,6 +400,13 @@ export class ThemeManager {
   ): Promise<void> {
     console.debug("[ThemeManager] Removing theme:", theme.name);
     try {
+      clearThemeRuntime();
+
+      // Disconnect the head observer BEFORE removing the style element,
+      // otherwise the removal fires the observer and it would no-op only
+      // because the style is already gone — wasted work, but harmless.
+      this.disconnectStyleObserver();
+
       // Remove custom CSS
       if (this.styleElement) {
         console.debug("[ThemeManager] Removing custom CSS");
@@ -448,7 +476,13 @@ export class ThemeManager {
   }
 
   /**
-   * Apply custom CSS to the document
+   * Apply custom CSS to the document. The `<style>` element is always
+   * re-appended to the end of `<head>` so it wins specificity ties
+   * against any styles SEQTA's late-loading injected.scss adds in dev
+   * mode (where `import("@/css/injected.scss")` is fire-and-forget and
+   * can resolve after the theme has already been applied). The head
+   * observer below keeps us at the end if anything else gets appended
+   * later (Vite HMR, another script-injected stylesheet, etc.).
    */
   private applyCustomCSS(css: string): void {
     console.debug("[ThemeManager] Applying custom CSS");
@@ -456,14 +490,39 @@ export class ThemeManager {
       if (!this.styleElement) {
         this.styleElement = document.createElement("style");
         this.styleElement.id = "custom-theme";
-        document.head.appendChild(this.styleElement);
       }
       this.styleElement.textContent = css;
+      document.head.appendChild(this.styleElement);
+      this.ensureStyleStaysLast();
     } catch (error) {
       console.error("[ThemeManager] Error applying custom CSS:", error);
     }
   }
 
+  /**
+   * Watch `<head>` for any child-list changes and re-append the theme
+   * style element if anything has been added after it. Idempotent: the
+   * observer's own re-append fires the callback again, but the early
+   * `lastElementChild === style` check short-circuits the second pass.
+   */
+  private ensureStyleStaysLast(): void {
+    if (this.headObserver) return;
+    this.headObserver = new MutationObserver(() => {
+      const style = this.styleElement;
+      if (!style || !document.head.contains(style)) return;
+      if (document.head.lastElementChild === style) return;
+      document.head.appendChild(style);
+    });
+    this.headObserver.observe(document.head, { childList: true });
+  }
+
+  private disconnectStyleObserver(): void {
+    if (this.headObserver) {
+      this.headObserver.disconnect();
+      this.headObserver = null;
+    }
+  }
+
   /**
    * Get list of available themes
    */
@@ -637,6 +696,15 @@ export class ThemeManager {
         throw new Error("Theme is missing required fields (id or name)");
       }
 
+      // Validate optional runtime hooks. Reject the install if either is
+      // malformed so a tampered theme cannot smuggle in unsafe values.
+      if (!validateThemeScript(themeData.themeScript)) {
+        throw new Error("Theme has invalid themeScript");
+      }
+      if (!validateThemeDom(themeData.themeDom)) {
+        throw new Error("Theme has invalid themeDom");
+      }
+
       const fromStore = meta?.fromStore ?? false;
       const serverUpdatedAtSec = meta?.serverUpdatedAtSec;
 
@@ -701,6 +769,8 @@ export class ThemeManager {
               ? true
               : undefined,
         adaptiveCssVariables: themeData.adaptiveCssVariables,
+        themeScript: themeData.themeScript,
+        themeDom: themeData.themeDom,
       };
 
       await this.saveTheme(theme);
diff --git a/src/plugins/built-in/themes/theme-runtime.ts b/src/plugins/built-in/themes/theme-runtime.ts
new file mode 100644
index 00000000..d1b988e8
--- /dev/null
+++ b/src/plugins/built-in/themes/theme-runtime.ts
@@ -0,0 +1,792 @@
+/**
+ * Theme runtime: minimal, locked-down hooks for themes that need a clock or
+ * a few decorative DOM elements (e.g. Noir City's day/night cycle and
+ * animated cars).
+ *
+ * Hard constraints:
+ *   - No `eval` and no execution of theme-author JS. Themes reference built-in
+ *     functions by name from a fixed allowlist.
+ *   - No network, storage, cookies, or SEQTA DOM access.
+ *   - Only mutations allowed are: CSS custom properties on <html>, a single
+ *     `data-city-state` attribute on <html>, and appending a fixed set of
+ *     decorative elements into `#bsplus-theme-runtime-root`.
+ */
+
+export type ThemeScriptSpec = {
+  onLoad?: string;
+  interval?: number;
+  onInterval?: string;
+};
+
+export type ThemeDomSpec = {
+  roadStrip?: boolean;
+  cars?: number;
+  /** @deprecated Use cityLayers flicker overlays instead. */
+  flickers?: number;
+  cityLayers?: boolean;
+};
+
+const ROOT_ID = "bsplus-theme-runtime-root";
+const WALLPAPER_ID = "bsplus-theme-wallpaper";
+const MAX_CARS = 10;
+const MAX_FLICKERS = 8;
+const MIN_INTERVAL_MS = 60_000;
+const DEFAULT_INTERVAL_MS = 600_000;
+
+/**
+ * IDs of decorative city layers injected when `themeDom.cityLayers` is on.
+ * Order matters: earlier entries paint behind later ones. Buildings sit
+ * behind the lit batches (so windows draw over the silhouettes); flicker
+ * frames sit over the lit batches so blinking windows hide steady ones.
+ * Sun and moon are last so they paint over everything else in the
+ * wallpaper stack (still behind #main via z-index 0).
+ */
+/**
+ * `city-buildings` always paints the night panorama; `city-day` paints
+ * the day panorama on top with opacity controlled by `--city-day-
+ * opacity`. The two stack so we can CSS-transition opacity between
+ * them at the day boundary, instead of snapping background-image (which
+ * doesn't animate). */
+const CITY_LAYER_IDS = [
+  "city-buildings",
+  "city-day",
+  "city-lights-1",
+  "city-lights-2",
+  "city-lights-3",
+  "city-flicker-a",
+  "city-flicker-b",
+  "city-sun",
+  "city-moon",
+] as const;
+
+// Built-in functions themes may reference by exact string match.
+const BUILTINS: Record<string, () => void> = {
+  "setTimeState()": setTimeState,
+  "setCityTime()": setCityTime,
+};
+
+let intervalHandle: ReturnType<typeof setInterval> | null = null;
+let lastTimeState: TimeState | null = null;
+let lastDomSpec: ThemeDomSpec | null = null;
+let bodyObserver: MutationObserver | null = null;
+let pageshowListenerAttached = false;
+let repaintScheduled = false;
+
+type TimeState = "night" | "dawn" | "day" | "dusk" | "evening";
+
+/**
+ * Sky colour anchors. Exactly one of these is published as
+ * `--city-sky-color` at any given moment, based on the discrete
+ * `timeStateForMinutes()` bucket. CSS handles the cross-fade between
+ * anchors via its own `transition: background-color` rule, so the sky
+ * is a flat colour during the whole duration of each phase and only
+ * animates on the boundary crossing itself.
+ *
+ *   night    near-black with a hint of blue
+ *   dawn     peachy sunrise — brighter than the previous dusty rose so
+ *            the lerp from night -> dawn -> day doesn't pass through
+ *            desaturated grey-purple in the middle.
+ *   day      soft pastel "skyblue" (#87CEEB, the CSS named colour). Was
+ *            previously a desaturated steel-blue that read as grey at
+ *            mid-lightness.
+ *   dusk     warm orange sunset, matching dawn's brightness so the
+ *            afternoon transition stays colourful.
+ *   evening  deep indigo, low chroma, settling toward night.
+ */
+const SKY_COLOR: Record<TimeState, string> = {
+  night: "#0d0d0f",
+  dawn: "#cc6a5a",
+  day: "#87ceeb",
+  dusk: "#d56a3a",
+  evening: "#111118",
+};
+
+/* ============================================================ *
+ * Dev-only time picker
+ *
+ * Flip this to `false` to remove the floating slider entirely
+ * (it's also automatically off in production builds via the
+ * `IS_DEV` check below).
+ * ============================================================ */
+const DEV_TIME_PICKER_ENABLED = true;
+
+const DEV_OVERRIDE_KEY = "bsplus-city-time-override";
+const IS_DEV = import.meta.env.MODE === "development";
+const DEV_PICKER_ID = "bsplus-city-dev-picker";
+
+function readDevOverride(): number | null {
+  if (!IS_DEV || !DEV_TIME_PICKER_ENABLED) return null;
+  try {
+    const raw = localStorage.getItem(DEV_OVERRIDE_KEY);
+    if (raw === null) return null;
+    const n = Number(raw);
+    if (Number.isFinite(n) && n >= 0 && n < 24 * 60) return n;
+  } catch {
+    // localStorage may be unavailable; ignore.
+  }
+  return null;
+}
+
+/**
+ * "Balanced 1h wedges" schedule:
+ *
+ *   00:00 .. 05:30   night    (dark)
+ *   05:30 .. 06:30   dawn     (peachy sunrise, ramping up)
+ *   06:30 .. 18:00   day      (pastel blue, the big stable block)
+ *   18:00 .. 19:00   dusk     (warm sunset)
+ *   19:00 .. 21:00   evening  (deep indigo, fading toward night)
+ *   21:00 .. 24:00   night
+ *
+ * The discrete bucket here drives `data-city-state` (used by the car
+ * sprite swap and the day panorama). The continuous sky-colour lerp in
+ * `TIME_BOUNDARIES` MUST use the same minute markers so the boundary
+ * the user sees in the dev slider matches the visible colour change.
+ */
+function timeStateForMinutes(minutes: number): TimeState {
+  if (minutes < 5 * 60 + 30) return "night";
+  if (minutes < 6 * 60 + 30) return "dawn";
+  if (minutes < 18 * 60) return "day";
+  if (minutes < 19 * 60) return "dusk";
+  if (minutes < 21 * 60) return "evening";
+  return "night";
+}
+
+function getMinutesOfDay(now: Date = new Date()): number {
+  const override = readDevOverride();
+  if (override !== null) return override;
+  return now.getHours() * 60 + now.getMinutes();
+}
+
+function getTimeState(now: Date = new Date()): TimeState {
+  return timeStateForMinutes(getMinutesOfDay(now));
+}
+
+function clamp01(value: number): number {
+  return Math.max(0, Math.min(1, value));
+}
+
+/**
+ * Sky colour publishing is intentionally NOT time-interpolated. We
+ * publish exactly one of the five `SKY_COLOR` anchors based on the
+ * discrete state from `timeStateForMinutes()`, and let CSS handle the
+ * cross-fade via its own `transition: background-color` on #content.
+ *
+ * That way the sky is a flat colour for the entire duration of each
+ * phase, and only animates between two anchors AT THE MOMENT the state
+ * boundary is crossed. The animation duration is decoupled from how
+ * long the phase lasts.
+ *
+ * Removed: the previous `lerpColor` + `TIME_BOUNDARIES` minute table.
+ */
+function skyColorForState(state: TimeState): string {
+  return SKY_COLOR[state];
+}
+
+function darknessForMinutes(minutes: number): number {
+  const noon = 12 * 60;
+  let distance = Math.abs(minutes - noon);
+  if (distance > 12 * 60) distance = 24 * 60 - distance;
+  return clamp01(distance / (12 * 60));
+}
+
+/**
+ * Per-phase lit-window opacities. Like `SKY_COLOR`, this is a flat lookup
+ * by discrete state — NOT a continuous function of minute-of-day. The
+ * existing 10s CSS `transition: opacity` on #city-lights-1/2/3 handles
+ * the cross-fade between phases when the discrete state changes.
+ *
+ *   night    everything lit — peak window activity
+ *   dawn     batch 1 only — a few early risers, lobby lights
+ *   day      all off
+ *   dusk     batch 1 fully on, batch 2 fading in
+ *   evening  batches 1 + 2 fully on, batch 3 partially — peak evening
+ *
+ * Tweak these freely; they're purely cosmetic and don't have to add up
+ * to anything.
+ */
+const LIT_OPACITIES: Record<TimeState, [number, number, number]> = {
+  night:   [1.0, 1.0, 1.0],
+  dawn:    [1.0, 0.0, 0.0],
+  day:     [0.0, 0.0, 0.0],
+  dusk:    [1.0, 0.6, 0.0],
+  evening: [1.0, 1.0, 0.5],
+};
+
+function litOpacitiesForState(state: TimeState): [number, number, number] {
+  return LIT_OPACITIES[state];
+}
+
+function sunForMinutes(minutes: number): { t: number; opacity: number } {
+  const sunrise = 6 * 60;
+  const sunset = 19 * 60;
+  if (minutes < sunrise || minutes >= sunset) return { t: 0, opacity: 0 };
+  return {
+    t: (minutes - sunrise) / (sunset - sunrise),
+    opacity: 1,
+  };
+}
+
+function moonForMinutes(minutes: number): { t: number; opacity: number } {
+  const sun = sunForMinutes(minutes);
+  if (sun.opacity > 0) return { t: 0, opacity: 0 };
+  const dusk = 19 * 60 + 30;
+  const dawn = 5 * 60;
+  if (minutes >= dusk) {
+    return { t: clamp01((minutes - dusk) / (24 * 60 - dusk)), opacity: 1 };
+  }
+  if (minutes < dawn) {
+    return { t: clamp01((dawn - minutes) / dawn), opacity: 1 };
+  }
+  return { t: 0.5, opacity: 1 };
+}
+
+function formatMinutes(minutes: number): string {
+  const h = Math.floor(minutes / 60);
+  const m = minutes % 60;
+  return `${h.toString().padStart(2, "0")}:${m.toString().padStart(2, "0")}`;
+}
+
+/**
+ * Read the clock and update `data-city-state` + sky colour on <html>. Only
+ * writes when the state actually changes, so CSS transitions are driven by
+ * real state changes rather than every tick.
+ */
+export function setTimeState(): void {
+  setCityTime();
+}
+
+/**
+ * Read the clock and publish continuous city variables plus the discrete
+ * `data-city-state` bucket used by CSS that still needs hard cuts (e.g. day
+ * panorama swap, night car sprites).
+ */
+export function setCityTime(): void {
+  const minutes = getMinutesOfDay();
+  const state = timeStateForMinutes(minutes);
+  const html = document.documentElement;
+
+  if (state !== lastTimeState) {
+    lastTimeState = state;
+    html.setAttribute("data-city-state", state);
+    html.style.setProperty("--city-time-state", state);
+  }
+
+  const darkness = darknessForMinutes(minutes);
+  const [lit1, lit2, lit3] = litOpacitiesForState(state);
+  const sun = sunForMinutes(minutes);
+  const moon = moonForMinutes(minutes);
+
+  html.style.setProperty("--city-sky-color", skyColorForState(state));
+  html.style.setProperty("--city-darkness", String(darkness));
+  // 1 only during the `day` phase; 0 in every other phase. CSS cross-
+  // fades the day panorama over the night panorama using this on a 10s
+  // opacity transition, which avoids the visual snap that
+  // `background-image` swaps cause (background-image doesn't animate).
+  html.style.setProperty("--city-day-opacity", state === "day" ? "1" : "0");
+  html.style.setProperty("--city-lit-1-opacity", String(lit1));
+  html.style.setProperty("--city-lit-2-opacity", String(lit2));
+  html.style.setProperty("--city-lit-3-opacity", String(lit3));
+  html.style.setProperty("--city-sun-t", String(sun.t));
+  html.style.setProperty("--city-sun-opacity", String(sun.opacity));
+  html.style.setProperty("--city-moon-t", String(moon.t));
+  html.style.setProperty("--city-moon-opacity", String(moon.opacity));
+}
+
+/**
+ * Validate the script spec strictly. Returns true if the spec is safe to run.
+ * Themes that include unknown calls or non-builtins are rejected wholesale.
+ */
+export function validateThemeScript(script: unknown): script is ThemeScriptSpec {
+  if (script == null) return true; // optional field
+  if (typeof script !== "object") return false;
+  const s = script as Record<string, unknown>;
+  for (const key of Object.keys(s)) {
+    if (key !== "onLoad" && key !== "interval" && key !== "onInterval") {
+      return false;
+    }
+  }
+  if (s.onLoad !== undefined && !isAllowedCall(s.onLoad)) return false;
+  if (s.onInterval !== undefined && !isAllowedCall(s.onInterval)) return false;
+  if (
+    s.interval !== undefined &&
+    (typeof s.interval !== "number" ||
+      !Number.isFinite(s.interval) ||
+      s.interval < MIN_INTERVAL_MS)
+  ) {
+    return false;
+  }
+  return true;
+}
+
+function isAllowedCall(value: unknown): boolean {
+  return typeof value === "string" && value in BUILTINS;
+}
+
+/**
+ * Validate the DOM spec. Caps counts and rejects unknown keys.
+ */
+export function validateThemeDom(dom: unknown): dom is ThemeDomSpec {
+  if (dom == null) return true;
+  if (typeof dom !== "object") return false;
+  const d = dom as Record<string, unknown>;
+  for (const key of Object.keys(d)) {
+    if (key !== "roadStrip" && key !== "cars" && key !== "flickers" && key !== "cityLayers") {
+      return false;
+    }
+  }
+  if (d.cityLayers !== undefined && typeof d.cityLayers !== "boolean") return false;
+  if (d.roadStrip !== undefined && typeof d.roadStrip !== "boolean") return false;
+  if (
+    d.cars !== undefined &&
+    (typeof d.cars !== "number" ||
+      !Number.isInteger(d.cars) ||
+      d.cars < 0 ||
+      d.cars > MAX_CARS)
+  ) {
+    return false;
+  }
+  if (
+    d.flickers !== undefined &&
+    (typeof d.flickers !== "number" ||
+      !Number.isInteger(d.flickers) ||
+      d.flickers < 0 ||
+      d.flickers > MAX_FLICKERS)
+  ) {
+    return false;
+  }
+  return true;
+}
+
+function callBuiltin(name: string): void {
+  const fn = BUILTINS[name];
+  if (!fn) return;
+  try {
+    fn();
+  } catch (e) {
+    console.error("[ThemeRuntime] Built-in failed:", name, e);
+  }
+}
+
+/**
+ * Run a validated themeScript: invoke `onLoad` once and start an interval
+ * timer for `onInterval` if configured. Idempotent — clears any prior
+ * interval before scheduling a new one so repeated calls (e.g. during
+ * theme re-apply races) don't leak timers.
+ */
+export function runThemeScript(script: ThemeScriptSpec | undefined): void {
+  if (intervalHandle !== null) {
+    clearInterval(intervalHandle);
+    intervalHandle = null;
+  }
+  if (!script || !validateThemeScript(script)) return;
+  if (script.onLoad) callBuiltin(script.onLoad);
+  if (script.onInterval) {
+    const period = Math.max(MIN_INTERVAL_MS, script.interval ?? DEFAULT_INTERVAL_MS);
+    intervalHandle = setInterval(() => callBuiltin(script.onInterval!), period);
+  }
+}
+
+function getOrCreateRoot(): HTMLElement {
+  let root = document.getElementById(ROOT_ID);
+  if (!root) {
+    root = document.createElement("div");
+    root.id = ROOT_ID;
+    root.setAttribute("aria-hidden", "true");
+  }
+  // Always parent under <body>: the runtime root uses `position: fixed`
+  // and needs to escape any stacking context SEQTA puts on `#content` so
+  // the sidebar can layer over it cleanly via z-index.
+  if (root.parentElement !== document.body) {
+    document.body.appendChild(root);
+  }
+  return root;
+}
+
+/**
+ * The wallpaper container is a *separate* sibling of the runtime root,
+ * never a child. We keep it independent so its existence is determined
+ * solely by `themeDom.cityLayers`, and so the road strip's tight 60px
+ * bottom geometry can't accidentally constrain the full-area city
+ * layers. All CSS positioning of cityscape/sun/moon happens via
+ * `position: fixed` on the layer divs themselves; this container only
+ * groups them for cheap teardown.
+ */
+function getOrCreateWallpaper(): HTMLElement {
+  let wallpaper = document.getElementById(WALLPAPER_ID);
+  if (!wallpaper) {
+    wallpaper = document.createElement("div");
+    wallpaper.id = WALLPAPER_ID;
+    wallpaper.setAttribute("aria-hidden", "true");
+  }
+  if (wallpaper.parentElement !== document.body) {
+    document.body.appendChild(wallpaper);
+  }
+  return wallpaper;
+}
+
+/** Content scripts run at `document_start`; defer until `<body>` exists. */
+function whenBodyReady(run: () => void): void {
+  if (document.body) {
+    run();
+    return;
+  }
+  document.addEventListener("DOMContentLoaded", run, { once: true });
+}
+
+function runtimeRootNeedsContent(spec: ThemeDomSpec): boolean {
+  const root = document.getElementById(ROOT_ID);
+  if (!root) return true;
+  if (spec.roadStrip && !document.getElementById("city-road")) return true;
+  const carCount = Math.min(spec.cars ?? 0, MAX_CARS);
+  if (carCount > 0 && root.querySelector(".city-car") === null) return true;
+  return false;
+}
+
+function cityWallpaperNeedsLayers(): boolean {
+  if (!lastDomSpec?.cityLayers) return false;
+  const wallpaper = document.getElementById(WALLPAPER_ID);
+  if (!wallpaper) return true;
+  return wallpaper.querySelector("#city-buildings") === null;
+}
+
+function repaintThemeDomIfNeeded(): void {
+  if (!lastDomSpec || !document.body) return;
+  if (runtimeRootNeedsContent(lastDomSpec)) {
+    const root = getOrCreateRoot();
+    populateRoot(root, lastDomSpec);
+  }
+  if (cityWallpaperNeedsLayers()) {
+    const wallpaper = getOrCreateWallpaper();
+    populateWallpaper(wallpaper);
+  }
+}
+
+function scheduleRepaintThemeDomIfNeeded(): void {
+  if (repaintScheduled) return;
+  repaintScheduled = true;
+  requestAnimationFrame(() => {
+    repaintScheduled = false;
+    repaintThemeDomIfNeeded();
+  });
+}
+
+function themeDomNeedsRepaint(): boolean {
+  if (!lastDomSpec) return false;
+  if (!document.getElementById(ROOT_ID)) return true;
+  if (lastDomSpec.cityLayers && !document.getElementById(WALLPAPER_ID)) {
+    return true;
+  }
+  return runtimeRootNeedsContent(lastDomSpec) || cityWallpaperNeedsLayers();
+}
+
+function populateWallpaper(wallpaper: HTMLElement): void {
+  while (wallpaper.firstChild) wallpaper.removeChild(wallpaper.firstChild);
+  for (const id of CITY_LAYER_IDS) {
+    const layer = document.createElement("div");
+    layer.id = id;
+    // `class` lets the theme target all cityscape overlays with a single
+    // rule for the shared fixed-positioning + background-attachment block.
+    if (
+      id.startsWith("city-buildings") ||
+      id === "city-day" ||
+      id.startsWith("city-lights") ||
+      id.startsWith("city-flicker")
+    ) {
+      layer.className = "city-cityscape-layer";
+    }
+    wallpaper.appendChild(layer);
+  }
+}
+
+const CAR_VARIANTS = ["car-sedan", "car-hatchback", "car-boxy"] as const;
+
+/**
+ * Populate the runtime root with the decorative DOM described by `dom`.
+ * Always wipes the root's existing children first so repeated calls leave
+ * exactly one road / N cars, no duplicates. The runtime root contains
+ * ONLY the road strip and cars — full-area city layers (buildings, lit
+ * batches, flicker, sun, moon) live in a separate `#bsplus-theme-wallpaper`
+ * container so the root's tight 60px bottom strip never grows.
+ */
+function populateRoot(root: HTMLElement, dom: ThemeDomSpec): void {
+  while (root.firstChild) root.removeChild(root.firstChild);
+
+  if (dom.roadStrip) {
+    const road = document.createElement("div");
+    road.id = "city-road";
+    root.appendChild(road);
+  }
+
+  const carCount = Math.min(dom.cars ?? 0, MAX_CARS);
+  for (let i = 1; i <= carCount; i++) {
+    const car = document.createElement("div");
+    const variant = CAR_VARIANTS[(i - 1) % CAR_VARIANTS.length];
+    car.className = `city-car city-car-${i} ${variant}`;
+    root.appendChild(car);
+  }
+
+  // Legacy scattered flicker dots. Themes that opt into `cityLayers` use
+  // the overlay-cross-fade flicker instead, so we skip these when the new
+  // system is active to avoid double flickering.
+  if (!dom.cityLayers) {
+    const flickerCount = Math.min(dom.flickers ?? 0, MAX_FLICKERS);
+    for (let i = 1; i <= flickerCount; i++) {
+      const flicker = document.createElement("div");
+      flicker.className = `city-win-flicker city-win-flicker-${i}`;
+      root.appendChild(flicker);
+    }
+  }
+}
+
+/**
+ * Watch `<body>` for the runtime root or wallpaper being removed (SPA
+ * re-renders, external code, etc.) and re-inject from the cached spec.
+ * Without this, intermittent reloads could leave the page with no road/
+ * cars or no cityscape layers even though the runtime believed they were
+ * mounted.
+ */
+function ensureBodyObserver(): void {
+  if (bodyObserver) return;
+  const attach = () => {
+    if (!document.body || bodyObserver) return;
+    bodyObserver = new MutationObserver(() => {
+      if (themeDomNeedsRepaint()) scheduleRepaintThemeDomIfNeeded();
+    });
+    // Only direct children of <body>: the theme nodes are appended there.
+    // Watching the full subtree fired on every SEQTA menu/content mutation and
+    // could repaint decorative layers mid-navigation (felt like a page reload).
+    bodyObserver.observe(document.body, { childList: true });
+  };
+  whenBodyReady(attach);
+
+  if (!pageshowListenerAttached && typeof window !== "undefined") {
+    pageshowListenerAttached = true;
+    window.addEventListener(
+      "pageshow",
+      (event) => {
+        if (event.persisted) repaintThemeDomIfNeeded();
+      },
+      { capture: true },
+    );
+  }
+}
+
+/**
+ * Inject the decorative DOM scaffolding required by themes that opt in via
+ * `themeDom`. Idempotent: safe to call multiple times in a row without
+ * an intervening `clearThemeRuntime`. Everything is positioned/styled by
+ * theme CSS.
+ */
+export function injectThemeDom(dom: ThemeDomSpec | undefined): void {
+  if (!dom || !validateThemeDom(dom)) return;
+  lastDomSpec = dom;
+  ensureBodyObserver();
+
+  const mount = () => {
+    if (!lastDomSpec) return;
+    const spec = lastDomSpec;
+    if (runtimeRootNeedsContent(spec)) {
+      const root = getOrCreateRoot();
+      populateRoot(root, spec);
+    }
+    if (spec.cityLayers) {
+      if (cityWallpaperNeedsLayers()) {
+        const wallpaper = getOrCreateWallpaper();
+        populateWallpaper(wallpaper);
+      }
+    } else {
+      // Theme switched from a cityLayers theme to one without — tear down
+      // any leftover wallpaper so we don't paint stale buildings/sun.
+      document.getElementById(WALLPAPER_ID)?.remove();
+    }
+
+    // Suppress the slow `transition: background-color` for the very first
+    // frame after the theme CSS lands. Without this, the browser
+    // interpolates from SEQTA's pre-theme `background: unset` (light) to
+    // var(--city-sky-color) over 30s on every page load. Double rAF: the
+    // first runs after the next layout, the second after that frame has
+    // actually been painted with the attribute set, so we can safely
+    // remove it and let real state changes (night -> dawn etc.) animate.
+    const html = document.documentElement;
+    html.setAttribute("data-city-just-applied", "");
+    requestAnimationFrame(() => {
+      requestAnimationFrame(() => {
+        html.removeAttribute("data-city-just-applied");
+      });
+    });
+
+    mountDevTimePicker();
+  };
+
+  whenBodyReady(mount);
+}
+
+/**
+ * Dev-only floating time picker. Renders a slider (0..1440 minutes) plus a
+ * checkbox to toggle "use real clock". The override is persisted in
+ * `localStorage` so it survives reloads during a debugging session. The
+ * whole block is dead code in production builds (the `IS_DEV` check is
+ * static and Vite tree-shakes it out).
+ */
+function mountDevTimePicker(): void {
+  if (!IS_DEV || !DEV_TIME_PICKER_ENABLED) return;
+  if (document.getElementById(DEV_PICKER_ID)) return;
+
+  const initialOverride = readDevOverride();
+  const startMinutes =
+    initialOverride ?? new Date().getHours() * 60 + new Date().getMinutes();
+  const useReal = initialOverride === null;
+
+  const panel = document.createElement("div");
+  panel.id = DEV_PICKER_ID;
+  panel.setAttribute("aria-label", "City time override (dev mode)");
+  // Inline styles so the panel can't be styled away by the active theme.
+  Object.assign(panel.style, {
+    position: "fixed",
+    bottom: "12px",
+    right: "12px",
+    zIndex: "2147483647",
+    padding: "10px 12px",
+    background: "rgba(20, 20, 24, 0.92)",
+    color: "#e8e8f0",
+    font: "12px/1.4 system-ui, sans-serif",
+    borderRadius: "8px",
+    boxShadow: "0 4px 16px rgba(0, 0, 0, 0.4)",
+    border: "1px solid rgba(255, 255, 255, 0.08)",
+    pointerEvents: "auto",
+    userSelect: "none",
+    minWidth: "220px",
+  } satisfies Partial<CSSStyleDeclaration>);
+
+  const header = document.createElement("div");
+  header.textContent = "City time (dev)";
+  Object.assign(header.style, {
+    fontWeight: "600",
+    marginBottom: "6px",
+    opacity: "0.85",
+  } satisfies Partial<CSSStyleDeclaration>);
+  panel.appendChild(header);
+
+  const realRow = document.createElement("label");
+  Object.assign(realRow.style, {
+    display: "flex",
+    alignItems: "center",
+    gap: "6px",
+    marginBottom: "8px",
+    cursor: "pointer",
+  } satisfies Partial<CSSStyleDeclaration>);
+  const realCheck = document.createElement("input");
+  realCheck.type = "checkbox";
+  realCheck.checked = useReal;
+  realRow.appendChild(realCheck);
+  const realLabel = document.createElement("span");
+  realLabel.textContent = "Use real clock";
+  realRow.appendChild(realLabel);
+  panel.appendChild(realRow);
+
+  const slider = document.createElement("input");
+  slider.type = "range";
+  slider.min = "0";
+  slider.max = String(24 * 60 - 1);
+  slider.step = "5";
+  slider.value = String(startMinutes);
+  slider.disabled = useReal;
+  Object.assign(slider.style, {
+    width: "100%",
+    accentColor: "#c8b97a",
+  } satisfies Partial<CSSStyleDeclaration>);
+  panel.appendChild(slider);
+
+  const readout = document.createElement("div");
+  Object.assign(readout.style, {
+    marginTop: "4px",
+    opacity: "0.8",
+    fontVariantNumeric: "tabular-nums",
+  } satisfies Partial<CSSStyleDeclaration>);
+  panel.appendChild(readout);
+
+  function paintReadout(): void {
+    const m = Number(slider.value);
+    readout.textContent = useReal
+      ? "Real clock"
+      : `${formatMinutes(m)} · ${timeStateForMinutes(m)}`;
+  }
+
+  function applyOverride(): void {
+    try {
+      if (realCheck.checked) {
+        localStorage.removeItem(DEV_OVERRIDE_KEY);
+      } else {
+        localStorage.setItem(DEV_OVERRIDE_KEY, slider.value);
+      }
+    } catch (e) {
+      console.warn("[ThemeRuntime] Could not persist time override:", e);
+    }
+    // Force a full re-publish next tick by clearing the cached bucket;
+    // setCityTime() short-circuits the discrete state when unchanged but
+    // always re-writes the continuous vars.
+    lastTimeState = null;
+    setCityTime();
+    paintReadout();
+  }
+
+  realCheck.addEventListener("change", () => {
+    slider.disabled = realCheck.checked;
+    applyOverride();
+  });
+  slider.addEventListener("input", () => {
+    if (realCheck.checked) {
+      realCheck.checked = false;
+      slider.disabled = false;
+    }
+    applyOverride();
+  });
+
+  paintReadout();
+  document.body.appendChild(panel);
+}
+
+function unmountDevTimePicker(): void {
+  document.getElementById(DEV_PICKER_ID)?.remove();
+}
+
+/**
+ * Remove everything the runtime added: injected DOM, interval timer, custom
+ * properties, and the `data-city-state` attribute.
+ */
+export function clearThemeRuntime(): void {
+  if (intervalHandle !== null) {
+    clearInterval(intervalHandle);
+    intervalHandle = null;
+  }
+  // Disconnect the body observer BEFORE removing the root so the observer
+  // doesn't see its own teardown removal as "root went missing" and try to
+  // re-inject what we're trying to clear.
+  if (bodyObserver) {
+    bodyObserver.disconnect();
+    bodyObserver = null;
+  }
+  lastDomSpec = null;
+  lastTimeState = null;
+
+  const root = document.getElementById(ROOT_ID);
+  if (root) root.remove();
+  document.getElementById(WALLPAPER_ID)?.remove();
+
+  unmountDevTimePicker();
+
+  const html = document.documentElement;
+  html.removeAttribute("data-city-state");
+  html.removeAttribute("data-city-just-applied");
+  html.style.removeProperty("--city-time-state");
+  html.style.removeProperty("--city-sky-color");
+  html.style.removeProperty("--city-darkness");
+  html.style.removeProperty("--city-day-opacity");
+  html.style.removeProperty("--city-lit-1-opacity");
+  html.style.removeProperty("--city-lit-2-opacity");
+  html.style.removeProperty("--city-lit-3-opacity");
+  html.style.removeProperty("--city-sun-t");
+  html.style.removeProperty("--city-sun-opacity");
+  html.style.removeProperty("--city-moon-t");
+  html.style.removeProperty("--city-moon-opacity");
+}
diff --git a/src/seqta/ui/AddBetterSEQTAElements.ts b/src/seqta/ui/AddBetterSEQTAElements.ts
index 644f33c1..62007031 100644
--- a/src/seqta/ui/AddBetterSEQTAElements.ts
+++ b/src/seqta/ui/AddBetterSEQTAElements.ts
@@ -22,6 +22,9 @@ let sidebarAccessibilityObserver: MutationObserver | null = null;
 let sidebarTabOrderAnimationFrame: number | null = null;
 let sidebarAccessibilityListenersAttached = false;
 
+/** Marks menu rows that are off-screen in the drill stack (CSS blocks clicks). */
+const BSPLUS_SIDEBAR_OFFSCREEN = "bsplus-sidebar-offscreen";
+
 export async function getUserInfo() {
   if (cachedUserInfo) return cachedUserInfo;
 
@@ -493,9 +496,15 @@ function scheduleSidebarAccessibilityUpdate() {
     cancelAnimationFrame(sidebarTabOrderAnimationFrame);
   }
 
+  // Double rAF: SEQTA applies `.active` / updates `.sub` on the next frame
+  // after a click. Running earlier hid the submenu with `aria-hidden` while
+  // focus was still on a <label> inside it, which broke routing and sent
+  // the SPA back to home.
   sidebarTabOrderAnimationFrame = requestAnimationFrame(() => {
-    sidebarTabOrderAnimationFrame = null;
-    updateSidebarAccessibility();
+    requestAnimationFrame(() => {
+      sidebarTabOrderAnimationFrame = null;
+      updateSidebarAccessibility();
+    });
   });
 }
 
@@ -506,9 +515,10 @@ function handleSidebarKeyboardActivation(event: KeyboardEvent) {
   const menuItem = target.closest("#menu li, #menu section") as
     | HTMLElement
     | null;
-  if (!menuItem || target !== menuItem) return;
+  if (!menuItem) return;
 
   if (event.key === "Tab") {
+    if (target !== menuItem) return;
     const menu = document.getElementById("menu");
     if (!menu) return;
 
@@ -552,11 +562,52 @@ function handleSidebarKeyboardActivation(event: KeyboardEvent) {
   }
 }
 
+/**
+ * Keyboard tab order for the drilled-in sidebar only.
+ * SEQTA already sets `aria-hidden` on off-screen menu rows; we must not
+ * override that or hide `.sub` ourselves — doing so while a <label> inside
+ * the submenu still has focus breaks SEQTA's router and navigates to home.
+ */
+/** Every folder row on the path to the open list (e.g. Assessments → 2026_S1). */
+function getDrillFolderChain(
+  menu: HTMLElement,
+  visibleList: HTMLElement | null,
+): Set<HTMLElement> {
+  const chain = new Set<HTMLElement>();
+  let list: HTMLElement | null = visibleList;
+
+  while (list && menu.contains(list)) {
+    const folder = getSidebarListParentEntry(list);
+    if (!folder || !menu.contains(folder)) break;
+    chain.add(folder);
+
+    const containerUl = folder.parentElement;
+    if (!(containerUl instanceof HTMLElement)) break;
+    const parentSub = containerUl.closest(".sub");
+    if (!parentSub || !menu.contains(parentSub)) break;
+    const parentFolder = parentSub.parentElement;
+    if (!(parentFolder instanceof HTMLElement) || !menu.contains(parentFolder)) {
+      break;
+    }
+    chain.add(parentFolder);
+    list =
+      parentFolder.parentElement instanceof HTMLElement
+        ? parentFolder.parentElement
+        : null;
+  }
+
+  return chain;
+}
+
 function updateSidebarAccessibility() {
   const menu = document.getElementById("menu");
   if (!menu) return;
 
-  const visibleEntries = new Set(getVisibleSidebarEntries(menu));
+  const visibleList = getVisibleSidebarList(menu);
+  const visibleEntries = new Set(
+    visibleList ? getDirectSidebarEntries(visibleList) : [],
+  );
+  const drillFolders = getDrillFolderChain(menu, visibleList);
   const menuEntries = menu.querySelectorAll("li.item, section.item, li, section");
 
   for (const entry of menuEntries) {
@@ -565,28 +616,19 @@ function updateSidebarAccessibility() {
     const label = entry.querySelector(":scope > label") as HTMLLabelElement | null;
     if (!label) continue;
 
-    const childSubmenu = entry.querySelector(":scope > .sub") as HTMLElement | null;
-    const isHidden =
-      entry.offsetParent === null ||
-      window.getComputedStyle(entry).display === "none" ||
-      window.getComputedStyle(label).display === "none" ||
-      !visibleEntries.has(entry);
+    const interactive =
+      visibleEntries.has(entry) || drillFolders.has(entry);
 
-    if (isHidden) {
+    if (!interactive) {
+      entry.classList.add(BSPLUS_SIDEBAR_OFFSCREEN);
       entry.tabIndex = -1;
       label.tabIndex = -1;
-      entry.setAttribute("aria-hidden", "true");
-      label.setAttribute("aria-hidden", "true");
-      if (childSubmenu) {
-        childSubmenu.setAttribute("aria-hidden", "true");
-      }
       continue;
     }
 
+    entry.classList.remove(BSPLUS_SIDEBAR_OFFSCREEN);
     entry.tabIndex = 0;
     label.tabIndex = -1;
-    entry.removeAttribute("aria-hidden");
-    label.removeAttribute("aria-hidden");
 
     if (!entry.hasAttribute("role")) {
       entry.setAttribute("role", "button");
@@ -596,14 +638,6 @@ function updateSidebarAccessibility() {
     if (accessibleLabel) {
       entry.setAttribute("aria-label", accessibleLabel);
     }
-
-    if (childSubmenu) {
-      const isExpanded = entry.classList.contains("active");
-      entry.setAttribute("aria-expanded", String(isExpanded));
-      childSubmenu.setAttribute("aria-hidden", String(!isExpanded));
-    } else {
-      entry.removeAttribute("aria-expanded");
-    }
   }
 }
 
diff --git a/src/seqta/utils/Openers/OpenThemeOfTheMonthPopup.ts b/src/seqta/utils/Openers/OpenThemeOfTheMonthPopup.ts
index aaf6348a..c2729db3 100644
--- a/src/seqta/utils/Openers/OpenThemeOfTheMonthPopup.ts
+++ b/src/seqta/utils/Openers/OpenThemeOfTheMonthPopup.ts
@@ -45,10 +45,10 @@ export async function fetchThemeOfTheMonth(): Promise<ThemeOfTheMonthEntry | nul
   }
 }
 
-/** True when we have a new monthly entry the user hasn't dismissed yet. */
+/** True when the current month's entry should appear in the startup queue. */
 export function shouldShowThemeOfTheMonth(entry: ThemeOfTheMonthEntry | null): boolean {
   if (!entry || settingsState.themeOfTheMonthDisabled) return false;
-  return settingsState.themeOfTheMonthLastSeenId !== entry.id;
+  return settingsState.themeOfTheMonthDismissedMonth !== entry.month;
 }
 
 function escapeHTML(str: string): string {
@@ -108,18 +108,9 @@ async function resolvePopupHeroImageUrl(entry: ThemeOfTheMonthEntry): Promise<st
   return fallback || null;
 }
 
-function closeThemeOfTheMonthCard(
-  card: HTMLElement,
-  onDismissed?: () => void,
-  markSeen = true,
-) {
+function closeThemeOfTheMonthCard(card: HTMLElement, onDismissed?: () => void) {
   if (card.classList.contains("themeOfTheMonthCardClosing")) return;
 
-  if (markSeen) {
-    const entryId = card.dataset.entryId;
-    if (entryId) settingsState.themeOfTheMonthLastSeenId = entryId;
-  }
-
   card.classList.add("themeOfTheMonthCardClosing");
   window.setTimeout(() => {
     card.remove();
@@ -143,7 +134,6 @@ export async function OpenThemeOfTheMonthPopup(
 
   const card = stringToHTML(/* html */ `
     <aside id="theme-of-the-month-card" class="themeOfTheMonthCard" role="dialog" aria-label="Theme of the Month">
-      <button type="button" class="themeOfTheMonthCardClose" aria-label="Close Theme of the Month">×</button>
       ${
         heroUrl
           ? `<img class="themeOfTheMonthCardImage" src="${escapeHTML(heroUrl)}" alt="${escapeHTML(entry.title)}" />`
@@ -154,39 +144,74 @@ export async function OpenThemeOfTheMonthPopup(
         <h2>${escapeHTML(entry.title)}</h2>
         <p class="themeOfTheMonthCardDescription">${description}</p>
         <div class="themeOfTheMonthCardActions">
-          ${
-            linkedThemeId
-              ? `<button type="button" class="themeOfTheMonthCardPrimary">Open Store</button>`
-              : ""
-          }
-          <button type="button" class="themeOfTheMonthCardSecondary">Don't show again</button>
+          <div class="themeOfTheMonthCardActionsStart">
+            ${
+              linkedThemeId
+                ? `<button type="button" class="themeOfTheMonthCardPrimary">Open Store</button>`
+                : ""
+            }
+          </div>
+          <div class="themeOfTheMonthCardActionsEnd">
+            <button type="button" class="themeOfTheMonthCardSecondary">Close</button>
+            <button type="button" class="themeOfTheMonthCardDontShow">Don't show again</button>
+          </div>
+        </div>
+      </div>
+      <div class="themeOfTheMonthCardConfirm" hidden>
+        <div class="themeOfTheMonthCardConfirmInner">
+          <h3>Don't show again?</h3>
+          <p>Theme of the Month popups will be turned off. You can turn them back on in BetterSEQTA+ settings.</p>
+          <div class="themeOfTheMonthCardConfirmActions">
+            <button type="button" class="themeOfTheMonthCardConfirmCancel">Cancel</button>
+            <button type="button" class="themeOfTheMonthCardConfirmAccept">Don't show again</button>
+          </div>
         </div>
       </div>
     </aside>
   `).firstChild as HTMLElement;
 
-  card.dataset.entryId = entry.id;
   const autoCloseTimeout = window.setTimeout(() => {
     closeThemeOfTheMonthCard(card, onDismissed);
-  }, 12000);
+  }, 30_000);
 
-  const dismiss = (markSeen = true) => {
+  const dismiss = () => {
     window.clearTimeout(autoCloseTimeout);
-    closeThemeOfTheMonthCard(card, onDismissed, markSeen);
+    closeThemeOfTheMonthCard(card, onDismissed);
   };
 
   card.addEventListener("mouseenter", () => window.clearTimeout(autoCloseTimeout), { once: true });
 
-  card.querySelector(".themeOfTheMonthCardClose")?.addEventListener("click", () => {
+  const confirmEl = card.querySelector<HTMLElement>(".themeOfTheMonthCardConfirm");
+
+  card.querySelector(".themeOfTheMonthCardSecondary")?.addEventListener("click", () => {
+    settingsState.themeOfTheMonthDismissedMonth = entry.month;
     dismiss();
   });
 
   card.querySelector(".themeOfTheMonthCardPrimary")?.addEventListener("click", () => {
+    settingsState.themeOfTheMonthDismissedMonth = entry.month;
     dismiss();
     openThemeStoreWithHighlight(linkedThemeId!);
   });
 
-  card.querySelector(".themeOfTheMonthCardSecondary")?.addEventListener("click", () => {
+  const openDontShowConfirm = () => {
+    window.clearTimeout(autoCloseTimeout);
+    if (!confirmEl) return;
+    confirmEl.hidden = false;
+    requestAnimationFrame(() => confirmEl.classList.add("themeOfTheMonthCardConfirmVisible"));
+  };
+
+  card.querySelector(".themeOfTheMonthCardDontShow")?.addEventListener("click", openDontShowConfirm);
+
+  card.querySelector(".themeOfTheMonthCardConfirmCancel")?.addEventListener("click", () => {
+    if (!confirmEl) return;
+    confirmEl.classList.remove("themeOfTheMonthCardConfirmVisible");
+    window.setTimeout(() => {
+      confirmEl.hidden = true;
+    }, 160);
+  });
+
+  card.querySelector(".themeOfTheMonthCardConfirmAccept")?.addEventListener("click", () => {
     settingsState.themeOfTheMonthDisabled = true;
     dismiss();
   });
@@ -196,7 +221,7 @@ export async function OpenThemeOfTheMonthPopup(
 
 /**
  * Dev helper: fetch the current month's entry and show the popup immediately,
- * even if the user has already dismissed it this month.
+ * even if the user dismissed it for this calendar month.
  */
 export async function showThemeOfTheMonthPopupNow(): Promise<void> {
   const entry = await fetchThemeOfTheMonth();
@@ -207,7 +232,7 @@ export async function showThemeOfTheMonthPopupNow(): Promise<void> {
     return;
   }
 
-  settingsState.themeOfTheMonthLastSeenId = undefined;
+  settingsState.themeOfTheMonthDismissedMonth = undefined;
 
   if (document.getElementById("whatsnewbk")) {
     await closePopup();
diff --git a/src/seqta/utils/Openers/StartupPopupQueue.ts b/src/seqta/utils/Openers/StartupPopupQueue.ts
index 391c4a68..de10ee8b 100644
--- a/src/seqta/utils/Openers/StartupPopupQueue.ts
+++ b/src/seqta/utils/Openers/StartupPopupQueue.ts
@@ -15,7 +15,7 @@ type QueueStep = (goNext: () => void) => void;
 
 /**
  * Runs startup modals in order: What's New (if the extension just updated),
- * Theme of the Month (when a new monthly entry hasn't been seen), then shows
+ * Theme of the Month (when the user hasn't dismissed this calendar month), then shows
  * the SEQTA Engage toast (once, non-blocking).
  */
 export async function runStartupPopupQueue() {
diff --git a/src/types/CustomThemes.ts b/src/types/CustomThemes.ts
index 6170c167..faa3006f 100644
--- a/src/types/CustomThemes.ts
+++ b/src/types/CustomThemes.ts
@@ -26,6 +26,19 @@ export type CustomTheme = {
   userEdited?: boolean;
   /** CSS custom property names (e.g. `--my-accent`) that receive the same value as `--better-main` when adaptive colours apply. */
   adaptiveCssVariables?: string[];
+  /** Optional runtime hook for themes that need clock-driven CSS variables. See `theme-runtime.ts`. */
+  themeScript?: {
+    onLoad?: string;
+    interval?: number;
+    onInterval?: string;
+  };
+  /** Optional decorative DOM injection (e.g. animated cars). See `theme-runtime.ts`. */
+  themeDom?: {
+    roadStrip?: boolean;
+    cars?: number;
+    flickers?: number;
+    cityLayers?: boolean;
+  };
 };
 
 export type LoadedCustomTheme = CustomTheme & {
diff --git a/src/types/storage.ts b/src/types/storage.ts
index d859d5f5..9ee34640 100644
--- a/src/types/storage.ts
+++ b/src/types/storage.ts
@@ -36,7 +36,12 @@ export interface SettingsState {
   engageParentsAnnouncementShown?: boolean;
   /** One-time announcement: BS Cloud automatic settings sync (last in startup popup queue). */
   bsCloudAutoSyncAnnouncementShown?: boolean;
-  /** ID of the last Theme of the Month entry shown to the user (shows once per new entry). */
+  /**
+   * Calendar month (`YYYY-MM`) for which the user closed the Theme of the Month popup.
+   * Cleared automatically when a new month's entry is fetched (different `month`).
+   */
+  themeOfTheMonthDismissedMonth?: string;
+  /** @deprecated Migrated away; no longer read. */
   themeOfTheMonthLastSeenId?: string;
   /** Permanently disables Theme of the Month startup prompts. */
   themeOfTheMonthDisabled?: boolean;