diff --git a/modules/crowdsurf/components/crowdsurf.css b/modules/crowdsurf/components/crowdsurf.css
index c2f073a..b32ac29 100644
--- a/modules/crowdsurf/components/crowdsurf.css
+++ b/modules/crowdsurf/components/crowdsurf.css
@@ -1,5 +1,4 @@
 /* CrowdSurf module layout */
 main {
-	min-height: calc(100vh - 56px);
 	padding: 0;
 }
diff --git a/modules/crowdsurf/components/folk-crowdsurf-dashboard.ts b/modules/crowdsurf/components/folk-crowdsurf-dashboard.ts
index f5f265d..bd16928 100644
--- a/modules/crowdsurf/components/folk-crowdsurf-dashboard.ts
+++ b/modules/crowdsurf/components/folk-crowdsurf-dashboard.ts
@@ -856,7 +856,6 @@ class FolkCrowdSurfDashboard extends HTMLElement {
 
 		.cs-app {
 			display: flex; flex-direction: column; height: 100%;
-			min-height: calc(100vh - 56px);
 			background: var(--rs-bg-page);
 			color: var(--rs-text-primary);
 		}
diff --git a/modules/rbooks/components/books.css b/modules/rbooks/components/books.css
index 75bdaac..eb8e54b 100644
--- a/modules/rbooks/components/books.css
+++ b/modules/rbooks/components/books.css
@@ -1,4 +1 @@
 /* Books module layout */
-main {
-	min-height: calc(100vh - 56px);
-}
diff --git a/modules/rbooks/components/folk-book-reader.ts b/modules/rbooks/components/folk-book-reader.ts
index fcc3810..5f9b659 100644
--- a/modules/rbooks/components/folk-book-reader.ts
+++ b/modules/rbooks/components/folk-book-reader.ts
@@ -365,7 +365,6 @@ export class FolkBookReader extends HTMLElement {
 				display: block;
 				width: 100%;
 				height: 100%;
-				min-height: calc(100vh - 52px);
 				background: var(--rs-bg-page);
 			}
 
@@ -418,7 +417,7 @@ export class FolkBookReader extends HTMLElement {
 				flex-direction: column;
 				align-items: center;
 				justify-content: center;
-				height: calc(100vh - 52px);
+				height: 100%;
 				gap: 1rem;
 			}
 
@@ -457,7 +456,7 @@ export class FolkBookReader extends HTMLElement {
 				flex-direction: column;
 				align-items: center;
 				justify-content: center;
-				height: calc(100vh - 52px);
+				height: 100%;
 				gap: 0.5rem;
 			}
 			.error h3 { color: var(--rs-error); margin: 0; }
diff --git a/modules/rcart/components/cart.css b/modules/rcart/components/cart.css
index 158b3c7..a6cbb89 100644
--- a/modules/rcart/components/cart.css
+++ b/modules/rcart/components/cart.css
@@ -1,6 +1,5 @@
 /* Cart module layout */
 main {
-	min-height: calc(100vh - 56px);
 	padding: 0;
 }
 
@@ -20,9 +19,3 @@ main:has(folk-payment-page) .rapp-subnav,
 main:has(folk-group-buy-page) .rapp-subnav {
 	display: none;
 }
-
-@media (max-width: 600px) {
-	main {
-		min-height: calc(100vh - 44px);
-	}
-}
diff --git a/modules/rchoices/components/choices.css b/modules/rchoices/components/choices.css
index bb028f6..968c333 100644
--- a/modules/rchoices/components/choices.css
+++ b/modules/rchoices/components/choices.css
@@ -1,5 +1,4 @@
 /* Choices module layout */
 main {
-	min-height: calc(100vh - 56px);
 	padding: 0;
 }
diff --git a/modules/rdesign/mod.ts b/modules/rdesign/mod.ts
index 0275556..f82a1ca 100644
--- a/modules/rdesign/mod.ts
+++ b/modules/rdesign/mod.ts
@@ -72,9 +72,8 @@ routes.get("/", (c) => {
 });
 
 const RDESIGN_CSS = `
-/* Layout — prevent page scroll */
-html:has(.rd-app), html:has(.rd-app) body { overflow:hidden; height:100vh; }
-.rd-app { display:flex; flex-direction:column; height:calc(100vh - 56px); overflow:hidden; }
+/* Layout — fills viewport via shell flex layout */
+.rd-app { display:flex; flex-direction:column; height:100%; overflow:hidden; }
 .rd-toolbar { display:flex; align-items:center; gap:8px; padding:6px 12px; border-bottom:1px solid var(--rs-border); background:var(--rs-bg-surface); flex-shrink:0; }
 .rd-split { display:flex; flex:1; overflow:hidden; }
 .rd-chat { flex:1; display:flex; flex-direction:column; min-width:300px; border-right:1px solid var(--rs-border); background:var(--rs-bg-page); }
diff --git a/modules/rmaps/components/folk-map-viewer.ts b/modules/rmaps/components/folk-map-viewer.ts
index 7956446..442623d 100644
--- a/modules/rmaps/components/folk-map-viewer.ts
+++ b/modules/rmaps/components/folk-map-viewer.ts
@@ -2206,7 +2206,7 @@ class FolkMapViewer extends HTMLElement {
 			.room-name { font-size: 15px; font-weight: 600; }
 
 			.map-container {
-				width: 100%; height: calc(100vh - 220px); min-height: 300px;
+				width: 100%; height: 100%; min-height: 300px;
 				border-radius: 10px;
 				background: var(--rs-bg-surface-sunken); border: 1px solid var(--rs-border);
 				position: relative; overflow: hidden;
@@ -2219,7 +2219,7 @@ class FolkMapViewer extends HTMLElement {
 			.map-sidebar {
 				width: 220px; flex-shrink: 0;
 				background: var(--rs-glass-bg); border: 1px solid var(--rs-border); border-radius: 10px;
-				padding: 12px; max-height: calc(100vh - 280px); overflow-y: auto;
+				padding: 12px; max-height: 100%; overflow-y: auto;
 			}
 			.sidebar-title {
 				font-size: 11px; font-weight: 600; color: var(--rs-text-secondary);
@@ -2279,7 +2279,7 @@ class FolkMapViewer extends HTMLElement {
 			.mobile-bottom-sheet { display: none; }
 
 			@media (max-width: 768px) {
-				.map-container { height: calc(100vh - 48px); min-height: 250px; max-height: none; border-radius: 0; border: none; }
+				.map-container { height: 100%; min-height: 250px; max-height: none; border-radius: 0; border: none; }
 				.map-layout { flex-direction: column; }
 				.map-sidebar { display: none; }
 				.controls { display: none; }
diff --git a/modules/rmeets/components/folk-jitsi-room.ts b/modules/rmeets/components/folk-jitsi-room.ts
index d00727f..7d62746 100644
--- a/modules/rmeets/components/folk-jitsi-room.ts
+++ b/modules/rmeets/components/folk-jitsi-room.ts
@@ -61,10 +61,10 @@ class FolkJitsiRoom extends HTMLElement {
 	private render() {
 		this.shadow.innerHTML = `
 			<style>
-				:host { display: block; width: 100%; min-height: 70vh; }
-				.jitsi-container { width: 100%; height: 70vh; border-radius: 12px; overflow: hidden; background: #000; }
+				:host { display: flex; flex-direction: column; width: 100%; height: 100%; }
+				.jitsi-container { width: 100%; flex: 1; min-height: 0; border-radius: 12px; overflow: hidden; background: #000; }
 				.jitsi-container iframe { border: none !important; }
-				.loading { display: flex; align-items: center; justify-content: center; height: 70vh; color: var(--rs-text-muted, #888); font-family: system-ui, sans-serif; }
+				.loading { display: flex; align-items: center; justify-content: center; flex: 1; min-height: 0; color: var(--rs-text-muted, #888); font-family: system-ui, sans-serif; }
 				.director-strip { display: flex; gap: 6px; padding: 10px; background: var(--rs-bg-surface, #1a1a2e); border: 1px solid var(--rs-border, #333); border-radius: 0 0 12px 12px; overflow-x: auto; align-items: center; }
 				.director-thumb { position: relative; width: 160px; min-width: 160px; aspect-ratio: 16/9; border-radius: 6px; overflow: hidden; cursor: pointer; border: 2px solid transparent; background: #111; }
 				.director-thumb.active { border-color: #ef4444; }
diff --git a/modules/rnetwork/components/network.css b/modules/rnetwork/components/network.css
index 3567678..2bcfb1f 100644
--- a/modules/rnetwork/components/network.css
+++ b/modules/rnetwork/components/network.css
@@ -4,7 +4,7 @@ folk-graph-viewer {
 	flex-direction: column;
 	min-height: 400px;
 	padding: 20px;
-	height: calc(100vh - 60px);
+	height: 100%;
 }
 
 /* Canvas cursor states */
diff --git a/modules/rnotes/components/folk-notes-app.ts b/modules/rnotes/components/folk-notes-app.ts
index 7c9777d..3f3772f 100644
--- a/modules/rnotes/components/folk-notes-app.ts
+++ b/modules/rnotes/components/folk-notes-app.ts
@@ -3543,7 +3543,7 @@ Gear:          EUR  400 (10%)</code></pre><p><em>Maya is tracking expenses in rF
 				display: grid;
 				grid-template-columns: 260px 1fr;
 				min-height: 400px;
-				height: calc(100vh - 120px);
+				height: 100%;
 				position: relative;
 				transition: grid-template-columns 0.2s ease;
 			}
diff --git a/modules/rpubs/components/folk-pubs-editor.ts b/modules/rpubs/components/folk-pubs-editor.ts
index 3b41e3f..9199382 100644
--- a/modules/rpubs/components/folk-pubs-editor.ts
+++ b/modules/rpubs/components/folk-pubs-editor.ts
@@ -820,9 +820,10 @@ export class FolkPubsEditor extends HTMLElement {
 		return `<style>
 			:host {
 				display: block;
-				height: calc(100vh - 140px);
+				height: 100%;
 				background: var(--rs-bg-page);
 				color: var(--rs-text-primary);
+				overflow: hidden;
 			}
 
 			.wizard-layout {
@@ -1267,7 +1268,7 @@ export class FolkPubsEditor extends HTMLElement {
 			/* ── Responsive ── */
 
 			@media (max-width: 640px) {
-				:host { height: auto; min-height: calc(100vh - 56px); }
+				:host { height: auto; min-height: 100%; }
 				.editor-toolbar { gap: 0.5rem; }
 				.toolbar-left { flex-direction: column; gap: 0.375rem; }
 				.title-input, .author-input { max-width: 100%; flex: 1; }
diff --git a/modules/rpubs/components/pubs.css b/modules/rpubs/components/pubs.css
index ffd7e78..0f033bb 100644
--- a/modules/rpubs/components/pubs.css
+++ b/modules/rpubs/components/pubs.css
@@ -1,5 +1,4 @@
 /* Pubs module layout */
 main {
-	min-height: calc(100vh - 56px);
 	padding: 0;
 }
diff --git a/modules/rschedule/components/automation-canvas.css b/modules/rschedule/components/automation-canvas.css
index ab0f850..02fbc95 100644
--- a/modules/rschedule/components/automation-canvas.css
+++ b/modules/rschedule/components/automation-canvas.css
@@ -1,7 +1,7 @@
 /* rSchedule Automation Canvas — n8n-style workflow builder */
 folk-automation-canvas {
 	display: block;
-	height: calc(100vh - 60px);
+	height: 100%;
 }
 
 .ac-root {
diff --git a/modules/rsocials/components/campaign-planner.css b/modules/rsocials/components/campaign-planner.css
index 92d1469..5c2ac40 100644
--- a/modules/rsocials/components/campaign-planner.css
+++ b/modules/rsocials/components/campaign-planner.css
@@ -1,7 +1,7 @@
 /* rSocials Campaign Planner — n8n-style flow canvas */
 folk-campaign-planner {
 	display: block;
-	height: calc(100vh - 60px);
+	height: 100%;
 }
 
 .cp-root {
@@ -675,7 +675,7 @@ folk-campaign-planner {
 	display: flex;
 	flex-direction: column;
 	gap: 8px;
-	max-height: calc(100vh - 180px);
+	max-height: 100%;
 }
 
 .cp-pv-card {
diff --git a/modules/rsocials/components/campaign-workflow.css b/modules/rsocials/components/campaign-workflow.css
index c5675c0..354702a 100644
--- a/modules/rsocials/components/campaign-workflow.css
+++ b/modules/rsocials/components/campaign-workflow.css
@@ -1,7 +1,7 @@
 /* rSocials Campaign Workflow — n8n-style workflow builder */
 folk-campaign-workflow {
 	display: block;
-	height: calc(100vh - 92px);
+	height: 100%;
 }
 
 .cw-root {
@@ -578,7 +578,7 @@ folk-campaign-workflow {
 /* ── Mobile ── */
 @media (max-width: 768px) {
 	folk-campaign-workflow {
-		height: calc(100vh - 56px);
+		height: 100%;
 	}
 
 	.cw-palette {
diff --git a/modules/rsplat/components/splat.css b/modules/rsplat/components/splat.css
index 5f76a92..41bd3c2 100644
--- a/modules/rsplat/components/splat.css
+++ b/modules/rsplat/components/splat.css
@@ -18,7 +18,7 @@
   max-width: 1200px;
   margin: 0 auto;
   color: var(--splat-text);
-  min-height: calc(100vh - 56px);
+  min-height: 100%;
   background: var(--splat-bg);
 }
 
@@ -427,7 +427,7 @@ button.splat-viewer__save {
 .splat-viewer {
   position: relative;
   width: 100%;
-  height: calc(100vh - 56px);
+  height: 100%;
   background: var(--splat-bg);
   overflow: hidden;
 }
diff --git a/modules/rswag/components/swag.css b/modules/rswag/components/swag.css
index 0d179a4..1024f81 100644
--- a/modules/rswag/components/swag.css
+++ b/modules/rswag/components/swag.css
@@ -1,6 +1,5 @@
 /* Swag module layout */
 main {
-	min-height: calc(100vh - 56px);
 	padding: 0;
 }
 
diff --git a/modules/rtime/components/rtime.css b/modules/rtime/components/rtime.css
index a238c7b..e79240f 100644
--- a/modules/rtime/components/rtime.css
+++ b/modules/rtime/components/rtime.css
@@ -2,6 +2,6 @@
 folk-timebank-app {
 	display: flex;
 	flex-direction: column;
-	height: calc(100vh - var(--rs-header-height, 56px));
+	height: 100%;
 	min-height: 0;
 }
diff --git a/modules/rtrips/components/folk-trips-planner.ts b/modules/rtrips/components/folk-trips-planner.ts
index 9094d63..9276536 100644
--- a/modules/rtrips/components/folk-trips-planner.ts
+++ b/modules/rtrips/components/folk-trips-planner.ts
@@ -429,7 +429,7 @@ class FolkTripsPlanner extends HTMLElement {
 		if (this._mapInstance) { try { this._mapInstance.remove(); } catch {} this._mapInstance = null; this._mapMarkers = []; }
 		this.shadow.innerHTML = `
 		<style>
-			:host { display: flex; flex-direction: column; height: calc(100vh - 112px); font-family: system-ui, -apple-system, sans-serif; color: var(--rs-text-primary); overflow: hidden; }
+			:host { display: flex; flex-direction: column; height: 100%; font-family: system-ui, -apple-system, sans-serif; color: var(--rs-text-primary); overflow: hidden; }
 			* { box-sizing: border-box; }
 			.rtrips-shell { display: flex; flex-direction: column; height: 100%; min-height: 0; overflow: hidden; }
 			.rtrips-scroll { flex: 1; overflow-y: auto; min-height: 0; padding-bottom: 8px; }
diff --git a/server/shell.ts b/server/shell.ts
index a1e5d93..719bb44 100644
--- a/server/shell.ts
+++ b/server/shell.ts
@@ -309,10 +309,7 @@ export function renderShell(opts: ShellOptions): string {
         <button class="rstack-header__history-btn" id="history-btn" title="History"><svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"/><polyline points="12 6 12 12 16 14"/></svg></button>
         <rstack-history-panel></rstack-history-panel>
       </div>
-      <div class="rstack-header__dropdown-wrap">
-        <button class="rstack-header__settings-btn" id="settings-btn" title="Space Settings"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="3"/><path d="M19.4 15a1.65 1.65 0 0 0 .33 1.82l.06.06a2 2 0 0 1 0 2.83 2 2 0 0 1-2.83 0l-.06-.06a1.65 1.65 0 0 0-1.82-.33 1.65 1.65 0 0 0-1 1.51V21a2 2 0 0 1-2 2 2 2 0 0 1-2-2v-.09A1.65 1.65 0 0 0 9 19.4a1.65 1.65 0 0 0-1.82.33l-.06.06a2 2 0 0 1-2.83 0 2 2 0 0 1 0-2.83l.06-.06A1.65 1.65 0 0 0 4.68 15a1.65 1.65 0 0 0-1.51-1H3a2 2 0 0 1-2-2 2 2 0 0 1 2-2h.09A1.65 1.65 0 0 0 4.6 9a1.65 1.65 0 0 0-.33-1.82l-.06-.06a2 2 0 0 1 0-2.83 2 2 0 0 1 2.83 0l.06.06A1.65 1.65 0 0 0 9 4.68a1.65 1.65 0 0 0 1-1.51V3a2 2 0 0 1 2-2 2 2 0 0 1 2 2v.09a1.65 1.65 0 0 0 1 1.51 1.65 1.65 0 0 0 1.82-.33l.06-.06a2 2 0 0 1 2.83 0 2 2 0 0 1 0 2.83l-.06.06A1.65 1.65 0 0 0 19.4 9a1.65 1.65 0 0 0 1.51 1H21a2 2 0 0 1 2 2 2 2 0 0 1-2 2h-.09a1.65 1.65 0 0 0-1.51 1z"/></svg></button>
-        <rstack-space-settings space="${escapeAttr(spaceSlug)}" module-id="${escapeAttr(moduleId)}"></rstack-space-settings>
-      </div>
+      <button class="rstack-header__settings-btn" id="settings-btn" title="Space Settings"><svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="3"/><path d="M19.4 15a1.65 1.65 0 0 0 .33 1.82l.06.06a2 2 0 0 1 0 2.83 2 2 0 0 1-2.83 0l-.06-.06a1.65 1.65 0 0 0-1.82-.33 1.65 1.65 0 0 0-1 1.51V21a2 2 0 0 1-2 2 2 2 0 0 1-2-2v-.09A1.65 1.65 0 0 0 9 19.4a1.65 1.65 0 0 0-1.82.33l-.06.06a2 2 0 0 1-2.83 0 2 2 0 0 1 0-2.83l.06-.06A1.65 1.65 0 0 0 4.68 15a1.65 1.65 0 0 0-1.51-1H3a2 2 0 0 1-2-2 2 2 0 0 1 2-2h.09A1.65 1.65 0 0 0 4.6 9a1.65 1.65 0 0 0-.33-1.82l-.06-.06a2 2 0 0 1 0-2.83 2 2 0 0 1 2.83 0l.06.06A1.65 1.65 0 0 0 9 4.68a1.65 1.65 0 0 0 1-1.51V3a2 2 0 0 1 2-2 2 2 0 0 1 2 2v.09a1.65 1.65 0 0 0 1 1.51 1.65 1.65 0 0 0 1.82-.33l.06-.06a2 2 0 0 1 2.83 0 2 2 0 0 1 0 2.83l-.06.06A1.65 1.65 0 0 0 19.4 9a1.65 1.65 0 0 0 1.51 1H21a2 2 0 0 1 2 2 2 2 0 0 1-2 2h-.09a1.65 1.65 0 0 0-1.51 1z"/></svg></button>
     </div>
     <div class="rstack-header__center">
       <rstack-mi></rstack-mi>
@@ -346,7 +343,7 @@ export function renderShell(opts: ShellOptions): string {
   <main id="app"${moduleId === "rspace" ? ' class="canvas-layout"' : ''}>
     ${renderModuleSubNav(moduleId, spaceSlug, visibleModules, opts.isSubdomain ?? IS_PRODUCTION)}
     ${opts.tabs ? renderTabBar(opts.tabs, opts.activeTab, opts.tabBasePath || ((opts.isSubdomain ?? IS_PRODUCTION) ? `/${escapeAttr(moduleId)}` : `/${escapeAttr(spaceSlug)}/${escapeAttr(moduleId)}`)) : ''}
-    ${body}
+    <div class="rapp-content">${body}</div>
   </main>
 
   ${renderWelcomeOverlay()}
@@ -422,15 +419,15 @@ export function renderShell(opts: ShellOptions): string {
       const minimized = document.body.classList.toggle('rspace-headers-minimized');
       localStorage.setItem('rspace_headers_minimized', minimized ? '1' : '0');
     });
-    // ── Settings panel toggle (close history first) ──
+    // ── Settings modal (close history first) ──
     document.getElementById('settings-btn')?.addEventListener('click', () => {
       document.querySelector('rstack-history-panel')?.close();
-      document.querySelector('rstack-space-settings')?.toggle();
+      const sw = document.querySelector('rstack-space-switcher');
+      if (sw) sw.openSettingsModal('${spaceSlug}', '${spaceName || spaceSlug}');
     });
 
-    // ── History panel toggle (close settings first) ──
+    // ── History panel toggle ──
     document.getElementById('history-btn')?.addEventListener('click', () => {
-      document.querySelector('rstack-space-settings')?.close();
       document.querySelector('rstack-history-panel')?.toggle();
     });
 
@@ -1105,9 +1102,6 @@ export function renderShell(opts: ShellOptions): string {
         console.log('[shell] layer-switch:', moduleId, 'layerId:', layerId, 'tabCache:', !!tabCache, 'layers:', layers.length);
         currentModuleId = moduleId;
         saveTabs();
-        // Update settings panel to show config for the newly active module
-        const sp = document.querySelector('rstack-space-settings');
-        if (sp) sp.setAttribute('module-id', moduleId);
         if (tabCache) {
           const switchId = moduleId; // capture for staleness check
           tabCache.switchTo(moduleId).then(ok => {
@@ -2039,15 +2033,12 @@ const SUBNAV_CSS = `
   border-bottom: 1px solid var(--rs-border);
   background: var(--rs-bg-surface);
   scrollbar-width: none;
-  position: sticky;
-  top: 93px;
+  flex-shrink: 0;
   z-index: 100;
 }
 .rapp-subnav::-webkit-scrollbar { display: none; }
 @media (max-width: 640px) {
   .rapp-subnav {
-    position: relative;
-    top: auto;
     padding: 0.375rem 0.75rem;
     gap: 0.25rem;
   }
@@ -2134,20 +2125,15 @@ const TABBAR_CSS = `
   border-bottom: 1px solid var(--rs-border);
   background: var(--rs-bg-surface);
   scrollbar-width: none;
-  position: sticky;
-  top: 92px;
+  flex-shrink: 0;
   z-index: 100;
 }
 .rapp-tabbar::-webkit-scrollbar { display: none; }
-.rapp-subnav + .rapp-tabbar { top: 130px; }
 @media (max-width: 640px) {
   .rapp-tabbar {
-    position: relative;
-    top: auto;
     padding: 0.25rem 0.75rem;
     gap: 0.25rem;
   }
-  .rapp-subnav + .rapp-tabbar { top: auto; }
 }
 `;
 
diff --git a/website/public/shell.css b/website/public/shell.css
index 9bfa523..7e86db4 100644
--- a/website/public/shell.css
+++ b/website/public/shell.css
@@ -78,9 +78,6 @@ body.rspace-banner-visible .rstack-tab-row {
 body.rspace-banner-visible #app {
   padding-top: 128px; /* 36px banner + 92px normal */
 }
-body.rspace-banner-visible .rapp-subnav {
-  top: 129px;
-}
 @media (max-width: 640px) {
   .rspace-banner {
     font-size: 0.75rem;
@@ -92,7 +89,6 @@ body.rspace-banner-visible .rapp-subnav {
   body.rspace-banner-visible .rstack-header { top: 0; }
   body.rspace-banner-visible .rstack-tab-row { top: 0; }
   body.rspace-banner-visible #app { padding-top: 0; }
-  body.rspace-banner-visible .rapp-subnav { top: auto; }
   .rspace-banner { position: sticky; }
 }
 
@@ -229,14 +225,30 @@ body.rspace-banner-visible .rapp-subnav {
 
 #app {
   padding-top: 92px; /* Below fixed header (56px) + tab row (36px) */
-  min-height: 100vh;
+  height: 100vh;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
 }
 
-/* When canvas module is active, make it fill the viewport */
-#app.canvas-layout {
-  padding-top: 92px;
-  height: 100vh;
-  overflow: hidden;
+/* .rapp-content fills below subnav/tabbar — scrollable for landing pages, app views fill exactly */
+.rapp-content {
+  flex: 1;
+  min-height: 0;
+  overflow: auto;
+  position: relative;
+  display: flex;
+  flex-direction: column;
+}
+/* When a single child (app view component), fill the viewport */
+.rapp-content > :only-child {
+  flex: 1;
+  min-height: 0;
+}
+/* Tab panes: active pane fills, hidden ones don't participate in flex */
+.rapp-content > .rspace-tab-pane--active {
+  flex: 1;
+  min-height: 0;
 }
 
 /* ── Standalone mode (no app/space switcher) ── */
@@ -481,28 +493,23 @@ body.rstack-sidebar-open #toolbar {
     position: sticky;
     top: 0;
   }
-  #app {
-    padding-top: 0;
-  }
-  /* Canvas on mobile: header/tab-row are sticky (in-flow), so body must
-     become a flex column to prevent the 100vh #app from overflowing. */
-  html:has(#app.canvas-layout),
-  body:has(#app.canvas-layout) {
+  /* Mobile: body becomes flex column so #app fills below sticky header/tabs */
+  html, body {
     height: 100dvh;
     overflow: hidden;
     overscroll-behavior: none;
   }
-  body:has(#app.canvas-layout) {
+  body {
     display: flex;
     flex-direction: column;
   }
-  body:has(#app.canvas-layout) .rstack-header {
+  .rstack-header {
     flex-shrink: 0;
   }
-  body:has(#app.canvas-layout) .rstack-tab-row {
+  .rstack-tab-row {
     flex-shrink: 0;
   }
-  #app.canvas-layout {
+  #app {
     padding-top: 0;
     height: auto;
     flex: 1;
@@ -512,7 +519,7 @@ body.rstack-sidebar-open #toolbar {
     position: relative;
     top: 0;
     width: 100%;
-    height: calc(100vh - 80px);
+    flex: 1;
     min-height: 400px;
   }
   .rapp-nav {
@@ -548,16 +555,12 @@ body.rstack-sidebar-open #toolbar {
   display: block;
 }
 
-/* When canvas is active, the tab pane must fill the viewport so #canvas height:100% works */
-#app.canvas-layout > .rspace-tab-pane--active {
-  height: 100%;
-}
-
 .rspace-tab-loading {
   display: flex;
   align-items: center;
   justify-content: center;
-  min-height: calc(100vh - 92px);
+  flex: 1;
+  min-height: 0;
 }
 
 .rspace-tab-spinner {
@@ -612,9 +615,6 @@ body.rspace-headers-minimized #app.canvas-layout {
   padding-top: 0;
 }
 body.rspace-headers-minimized .rapp-subnav {
-  position: fixed;
-  top: 0; left: 0; right: 0;
-  z-index: 9997;
   height: 28px;
   padding: 2px 8px;
   overflow: hidden;
@@ -645,8 +645,4 @@ body.rspace-headers-minimized .rapp-subnav {
     overflow: hidden;
     transform: none;
   }
-  body.rspace-headers-minimized .rapp-subnav {
-    position: sticky;
-    top: 0;
-  }
 }