diff --git a/assets/theme-v2/css/accordion.css b/assets/theme-v2/css/accordion.css
index b650f518e..df65a0332 100644
--- a/assets/theme-v2/css/accordion.css
+++ b/assets/theme-v2/css/accordion.css
@@ -75,8 +75,7 @@ details.vertical-accordion summary::-webkit-details-marker {
 }
 
 .horizontal-accordion-toggle__icon,
-.vertical-accordion__chevron,
-.tool-display-mode__chevron {
+.vertical-accordion__chevron {
   --accordion-button-border: var(--line);
   --accordion-button-background: var(--panel-soft);
   --accordion-button-color: var(--gold);
@@ -109,8 +108,7 @@ details.vertical-accordion summary::-webkit-details-marker {
   margin-left: auto
 }
 
-.vertical-accordion__chevron .theme-icon,
-.tool-display-mode__chevron .theme-icon {
+.vertical-accordion__chevron .theme-icon {
   height: var(--space-14);
   width: var(--space-14)
 }
diff --git a/assets/theme-v2/css/layout.css b/assets/theme-v2/css/layout.css
index b392b3306..be0dab165 100644
--- a/assets/theme-v2/css/layout.css
+++ b/assets/theme-v2/css/layout.css
@@ -196,7 +196,6 @@ div {
   min-width: var(--space-0)
 }
 
-body.tool-focus-mode .site-header,
 body.tool-focus-mode .page-title,
 body.tool-focus-mode .footer {
   display: none !important
@@ -313,6 +312,10 @@ body.tool-focus-mode:has(.tool-workspace--fullscreen-chrome) .site-header {
   z-index: var(--z-index-lg)
 }
 
+body.tool-focus-mode .site-header > .container.nav {
+  display: none !important
+}
+
 body.tool-focus-mode:has(.tool-workspace--fullscreen-chrome) .footer {
   inset-block-end: var(--space-0);
   inset-inline: var(--space-0);
diff --git a/assets/theme-v2/css/panels.css b/assets/theme-v2/css/panels.css
index 74f68f0c0..901895252 100644
--- a/assets/theme-v2/css/panels.css
+++ b/assets/theme-v2/css/panels.css
@@ -274,11 +274,7 @@ body.tool-focus-mode .tool-center-panel:has(>details.vertical-accordion)>p {
   border-radius: var(--radius-lg);
   background: var(--panel);
   box-shadow: var(--shadow-lg);
-  overflow: hidden;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  gap: var(--space-12)
+  overflow: hidden
 }
 
 .tool-display-mode summary {
@@ -286,12 +282,15 @@ body.tool-focus-mode .tool-center-panel:has(>details.vertical-accordion)>p {
   font-weight: var(--font-weight-heavy);
   cursor: pointer;
   list-style: none;
-  padding: var(--space-10) var(--space-44) var(--space-10) var(--space-10);
+  padding: var(--space-10);
   display: flex;
   align-items: center;
-  justify-content: center;
-  gap: var(--space-10);
-  flex: 0 0 auto
+  flex-direction: row;
+  flex-wrap: wrap;
+  justify-content: flex-start;
+  gap: var(--space-8) var(--space-10);
+  min-width: var(--space-0);
+  width: 100%
 }
 
 .tool-display-mode summary::-webkit-details-marker {
@@ -299,20 +298,17 @@ body.tool-focus-mode .tool-center-panel:has(>details.vertical-accordion)>p {
 }
 
 .tool-display-mode__mode-icon {
-  color: var(--cyan)
-}
-
-.tool-display-mode__chevron {
-  position: absolute;
-  right: var(--space-12);
-  top: 50%;
-  transform: translateY(-50%);
-  z-index: var(--z-index-sm)
+  color: var(--gold);
+  flex: 0 0 auto;
+  height: calc(var(--icon-size-sm) * 2.6);
+  margin-left: auto;
+  width: calc(var(--icon-size-sm) * 2.6)
 }
 
 .tool-display-mode__badge {
-  width: 64px;
-  height: 64px;
+  flex: 0 0 auto;
+  width: 128px;
+  height: 128px;
   object-fit: contain;
   object-position: center;
   border: 0;
@@ -320,71 +316,19 @@ body.tool-focus-mode .tool-center-panel:has(>details.vertical-accordion)>p {
   background: transparent
 }
 
-.tool-display-mode__body {
-  display: grid;
-  grid-template-columns: auto minmax(var(--space-0), 1fr);
-  grid-template-rows: auto auto;
-  align-items: center;
-  column-gap: var(--space-15);
-  row-gap: var(--space-8);
-  min-width: var(--space-0);
-  padding: var(--space-10) var(--space-14) var(--space-10) var(--space-0)
-}
-
-.tool-display-mode__identity-row {
-  display: contents
-}
-
-.tool-display-mode__navigation-row {
-  grid-column: 2;
-  grid-row: 2;
-  display: flex;
-  align-items: center;
-  gap: var(--space-14);
-  flex-wrap: wrap
-}
-
-.tool-display-mode__navigation-link {
-  align-items: center;
-  color: var(--text);
-  display: inline-flex;
-  gap: var(--space-6);
-  line-height: var(--line-height-tight)
-}
-
-.tool-display-mode__navigation-link:hover,
-.tool-display-mode__navigation-link:focus-visible {
-  color: var(--gold)
-}
-
-.tool-display-mode__navigation-link--disabled {
-  color: var(--muted)
-}
-
-.tool-display-mode__navigation-icon {
-  color: currentColor
-}
-
 .tool-display-mode__character {
-  grid-column: 1;
-  grid-row: 1 / span 2;
-  width: 225px;
-  height: 127px;
+  width: min(224px, 100%);
+  height: auto;
   object-fit: contain;
   display: block;
-  flex: 0 0 auto
+  flex: 0 0 min(224px, 100%);
+  min-width: min(144px, 100%)
 }
 
 .tool-display-mode__fullscreen-name {
-  display: none;
-  white-space: nowrap
-}
-
-.tool-display-mode__description {
-  grid-column: 2;
-  grid-row: 1;
-  color: var(--gold);
-  font-weight: var(--font-weight-heavy);
+  display: inline-flex;
+  flex: 1 1 4rem;
+  min-width: var(--space-0);
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap
@@ -393,17 +337,21 @@ body.tool-focus-mode .tool-center-panel:has(>details.vertical-accordion)>p {
 body.tool-focus-mode .tool-display-mode {
   border-color: var(--line);
   background: var(--panel);
-  box-shadow: var(--shadow-lg);
-  justify-content: center
+  box-shadow: var(--shadow-lg)
 }
 
-body.tool-focus-mode .tool-display-mode__fullscreen-name {
-  display: inline
+body.tool-focus-mode .tool-display-mode__badge {
+  width: 64px;
+  height: 64px
 }
 
-body.tool-focus-mode .tool-display-mode__badge {
-  width: 32px;
-  height: 32px
+body.tool-focus-mode .tool-display-mode__character {
+  display: none
+}
+
+body.tool-focus-mode .tool-display-mode__fullscreen-name {
+  justify-content: center;
+  text-align: center
 }
 
 .side-menu a {
diff --git a/assets/theme-v2/css/status.css b/assets/theme-v2/css/status.css
index a82c83065..81af7d308 100644
--- a/assets/theme-v2/css/status.css
+++ b/assets/theme-v2/css/status.css
@@ -135,11 +135,11 @@ body.tool-focus-mode .toolbox-status-bar {
 
 body.tool-focus-mode {
   --toolbox-status-bar-height: var(--space-52);
-  --toolbox-status-top-reserve: var(--space-0)
+  --toolbox-status-top-reserve: var(--space-78)
 }
 
 body.tool-focus-mode:has(.platform-banner) {
-  --toolbox-status-top-reserve: var(--space-52)
+  --toolbox-status-top-reserve: var(--space-78)
 }
 
 body.tool-focus-mode .tool-workspace {
@@ -165,6 +165,10 @@ body.tool-focus-mode .tool-center-panel {
   color: var(--text)
 }
 
+body.tool-focus-mode [data-platform-banner-placement="footer"] {
+  display: none !important
+}
+
 .platform-banner__inner {
   width: var(--container-width);
   margin: var(--space-0) auto;
diff --git a/assets/theme-v2/js/tool-display-mode.js b/assets/theme-v2/js/tool-display-mode.js
index cae5febcf..f35aa06e9 100644
--- a/assets/theme-v2/js/tool-display-mode.js
+++ b/assets/theme-v2/js/tool-display-mode.js
@@ -73,14 +73,8 @@
         document.querySelectorAll("details.vertical-accordion").forEach(wireVerticalAccordionChevron);
     }
 
-    function updateToolDisplayModeChevron() {
-        const iconName = displayMode.open ? "chevron-up" : "chevron-down";
-        const shell = createChevronShell(iconName, "tool-display-mode__chevron", "tool-display-mode__chevron-icon");
-        replaceIconNode(summary, ":scope > .tool-display-mode__chevron", shell);
-    }
-
     function updateToolDisplayModeModeIcon() {
-        const iconName = document.body.classList.contains("tool-focus-mode") || document.fullscreenElement
+        const iconName = document.body.classList.contains("tool-focus-mode")
             ? "exit-fullscreen"
             : "fullscreen";
         const icon = createThemeIconNode(iconName, "layout-icon tool-display-mode__mode-icon");
@@ -107,7 +101,6 @@
     function refreshThemeIcons() {
         refreshVerticalAccordionChevrons();
         updateToolDisplayModeModeIcon();
-        updateToolDisplayModeChevron();
         refreshHorizontalToggleIcons();
     }
 
@@ -146,68 +139,24 @@
     const summary = document.createElement("summary");
     summary.setAttribute("aria-label", "Tool Display Mode");
     summary.title = "Tool Display Mode";
-    summary.appendChild(createThemeIconNode("fullscreen", "layout-icon tool-display-mode__mode-icon"));
 
     const badge = document.createElement("img");
     badge.className = "tool-display-mode__badge";
     badge.src = publicImageSource(slot.dataset.toolIconSrc, "badges");
     badge.alt = toolName + " badge";
-    summary.appendChild(badge);
 
     const fullscreenName = document.createElement("span");
     fullscreenName.className = "tool-display-mode__fullscreen-name";
     fullscreenName.textContent = toolName;
-    summary.appendChild(fullscreenName);
-    displayMode.appendChild(summary);
-    displayMode.addEventListener("toggle", updateToolDisplayModeChevron);
-
-    const body = document.createElement("div");
-    body.className = "tool-display-mode__body";
-
-    const identityRow = document.createElement("div");
-    identityRow.className = "tool-display-mode__identity-row content-cluster";
-    identityRow.dataset.toolDisplayModeRow = "identity";
 
     const character = document.createElement("img");
     character.className = "tool-display-mode__character";
     character.src = publicImageSource(slot.dataset.toolCharacterSrc, "characters");
     character.alt = toolName + " character";
-    identityRow.appendChild(character);
-
-    const description = document.createElement("span");
-    description.className = "tool-display-mode__description";
-    description.textContent = toolName;
-    identityRow.appendChild(description);
-    body.appendChild(identityRow);
-    displayMode.appendChild(body);
+    summary.append(badge, fullscreenName, character, createThemeIconNode("fullscreen", "layout-icon tool-display-mode__mode-icon"));
+    displayMode.append(summary);
     slot.replaceWith(displayMode);
 
-    function createNavigationControl(direction, target) {
-        const controlLabel = direction === "previous" ? "Previous" : "Next";
-        const dataAttribute = direction === "previous" ? "toolNavPrevious" : "toolNavNext";
-        const iconName = direction === "previous" ? "chevron-left" : "chevron-right";
-        const icon = createThemeIconNode(iconName, "layout-icon tool-display-mode__navigation-icon");
-        const label = document.createTextNode(controlLabel + ": " + (target?.label || "Unavailable"));
-
-        if (!target || target.disabled) {
-            const disabledText = document.createElement("span");
-            disabledText.className = "pill tool-display-mode__navigation-link tool-display-mode__navigation-link--disabled";
-            disabledText.dataset[dataAttribute] = "disabled";
-            disabledText.append(icon, label);
-            return disabledText;
-        }
-
-        const link = document.createElement("a");
-        link.className = "tool-display-mode__navigation-link";
-        link.href = target.href;
-        link.dataset[dataAttribute] = target.kind;
-        if (target.group) {
-            link.dataset.toolNavGroup = target.group;
-        }
-        link.append(icon, label);
-        return link;
-    }
-
     function applyRegistryImages(registry) {
         const registryTool = registry.getToolBySlug(toolSlug);
         if (!registryTool) {
@@ -240,35 +189,24 @@
         badge.alt = registryName + " badge";
         fullscreenName.textContent = registryName;
         character.alt = registryName + " character";
-        description.textContent = registryName;
         badge.src = registry.getToolImageSource(registryTool, "badge");
         character.src = registry.getToolImageSource(registryTool, "tool");
     }
 
-    async function renderToolNavigation() {
+    async function renderToolDisplayMetadata() {
         try {
             const registry = await import("/toolbox/tool-registry-api-client.js");
             const registryDiagnostic = registry.getToolRegistryApiDiagnostic();
             if (registryDiagnostic) {
                 throw new Error(registryDiagnostic);
             }
-            const navigation = registry.getToolNavigationTargets(toolSlug);
             applyRegistryImages(registry);
-            const navigationRow = document.createElement("nav");
-            navigationRow.className = "tool-display-mode__navigation-row content-cluster";
-            navigationRow.dataset.toolDisplayModeRow = "navigation";
-            navigationRow.setAttribute("aria-label", "Tool build-order navigation");
-            navigationRow.append(
-                createNavigationControl("previous", navigation.previous),
-                createNavigationControl("next", navigation.next)
-            );
-            body.appendChild(navigationRow);
         } catch (error) {
-            console.warn("Tool navigation could not be loaded.", error);
+            console.warn("Tool display metadata could not be loaded.", error);
         }
     }
 
-    renderToolNavigation();
+    renderToolDisplayMetadata();
 
     async function enterToolMode() {
         document.body.classList.add("tool-focus-mode");
@@ -296,6 +234,7 @@
         } catch (error) {
             console.warn("Exit fullscreen failed.", error);
         }
+        updateToolDisplayModeModeIcon();
     }
 
     summary.addEventListener("click", function (event) {
@@ -309,15 +248,14 @@
     });
 
     document.addEventListener("fullscreenchange", function () {
-        if (!document.fullscreenElement && document.body.classList.contains("tool-focus-mode")) {
+        if (!document.fullscreenElement) {
             document.body.classList.remove("tool-focus-mode");
             displayMode.open = true;
-            refreshThemeIcons();
         }
+        refreshThemeIcons();
     });
 
     refreshVerticalAccordionChevrons();
-    updateToolDisplayModeChevron();
 
     document.querySelectorAll(".tool-workspace").forEach(function (workspace) {
         const columns = workspace.querySelectorAll(":scope > .tool-column");
diff --git a/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_branch-validation.md b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_branch-validation.md
new file mode 100644
index 000000000..9ae1a604c
--- /dev/null
+++ b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_branch-validation.md
@@ -0,0 +1,12 @@
+# PR_26176_005 Branch Validation
+
+| Check | Status | Notes |
+| --- | --- | --- |
+| Active branch is `PR_26176_005-tool-display-mode-single-line-layout` | PASS | Confirmed with `git branch --show-current`. |
+| Worktree reviewed before final packaging | PASS | Modified and untracked files were reviewed before report/ZIP regeneration. |
+| No `PR_26176_006` branch created | PASS | User explicitly cancelled stacked PR creation; this pass stayed on PR_26176_005. |
+| No `PR_26176_007` branch created | PASS | User explicitly cancelled stacked PR creation; this pass stayed on PR_26176_005. |
+| Accidental/unneeded PR_26176_001-004 artifacts removed | PASS | Untracked PR_26176_001 through PR_26176_004 report files were deleted from the worktree. |
+| Remaining changed files are PR_26176_005 scoped | PASS | Final changed-files report lists shared Tool Display Mode/layout code, focused Tool Display Mode validation, and required PR_26176_005 reports. |
+| Fullscreen platform banner correction stayed in PR_26176_005 | PASS | Shared CSS keeps the header placement banner visible and hides only `[data-platform-banner-placement="footer"]` in focus mode. |
+| Game Journey completion metrics storage warning handled | PASS | No SQLite/Postgres behavior changed; warning documented as Golf-owned external storage migration work. |
diff --git a/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_manual-validation-notes.md b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_manual-validation-notes.md
new file mode 100644
index 000000000..5ca28c801
--- /dev/null
+++ b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_manual-validation-notes.md
@@ -0,0 +1,22 @@
+# PR_26176_005 Manual Validation Notes
+
+## Manual Review
+- Confirmed the active branch is `PR_26176_005-tool-display-mode-single-line-layout`.
+- Reviewed modified and untracked files and removed accidental/unneeded PR_26176_001 through PR_26176_004 untracked report artifacts.
+- Reviewed `assets/theme-v2/js/tool-display-mode.js` to confirm the shared summary template directly renders badge, title, character image, and mode icon.
+- Reviewed `assets/theme-v2/css/panels.css`, `accordion.css`, `layout.css`, and `status.css` for shared-only Tool Display Mode/layout changes.
+- Confirmed no individual toolbox pages were modified.
+
+## Observations
+- The shared Tool Display Mode no longer renders the navigation row or `Previous:` / `Next:` labels.
+- The fullscreen/exit icon remains the final direct child of `<summary>`, uses the shared theme icon registry, and returns to the fullscreen SVG after exiting focus mode.
+- Normal mode displays both shared platform banner placements, header and footer, including the `Development Environment` message.
+- Fullscreen mode keeps the site header and header-placement platform banner visible, including `.platform-banner__inner` and the `Development Environment` message.
+- Fullscreen mode hides the footer-placement platform banner using `[data-platform-banner-placement="footer"]`.
+- Shared fullscreen CSS does not target `.platform-banner__inner` because both placement banners use the same inner structure.
+- Fullscreen mode hides the main `.site-header > div.container.nav` navigation container, including the brand/home navigation.
+- At the focused desktop Playwright width, the badge, title, character image, and fullscreen icon stay on one visual row without overlap or clipping.
+- Normal mode renders the shared character image at 224px wide with `height: auto`, and the badge at 128x128.
+- Fullscreen mode hides the shared character image, renders the badge at 64x64, centers the growing tool name, and keeps the exit-fullscreen icon anchored to the far right.
+- Older PR_26176_001/002 horizontal accordion color and footer status icon validation/styling were removed from this branch during final cleanup.
+- Game Journey completion metrics SQLite/Postgres behavior was not changed; the warning is Golf-owned external storage migration work outside this PR.
diff --git a/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_report.md b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_report.md
new file mode 100644
index 000000000..63f915949
--- /dev/null
+++ b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_report.md
@@ -0,0 +1,49 @@
+# PR_26176_005-tool-display-mode-single-line-layout Report
+
+## Scope Source
+- Active request: finalize existing branch `PR_26176_005-tool-display-mode-single-line-layout`.
+- Branch gate: current branch confirmed as `PR_26176_005-tool-display-mode-single-line-layout`; no `PR_26176_006` or `PR_26176_007` branch was created.
+- Worktree review: modified and untracked files were reviewed; accidental/unneeded `PR_26176_001` through `PR_26176_004` untracked report artifacts were removed.
+- Note: `docs_build/dev/BUILD_PR.md` still describes `PR_26175_ALFA_047-theme-v2-svg-icon-registry`, so the user prompt was treated as the operative BUILD scope for this PR.
+
+## Summary
+- Updated the shared Tool Display Mode template so the `<summary>` directly owns the badge, tool name, character image, and fullscreen/exit-fullscreen icon in that order.
+- Kept the fullscreen/exit-fullscreen theme icon as the final direct child of `<summary>`, gold, 2.6x the base layout icon, and anchored to the far right with `margin-left: auto`.
+- Removed the old Tool Display Mode chevron, stacked body/identity/description layout, and rendered navigation row UI.
+- Removed `nav.tool-display-mode__navigation-row`, `Previous: {tool}`, `Next: {tool}`, and CSS/JS used solely to render or populate that row.
+- Normal mode now displays both shared platform banner placements, `data-platform-banner-placement="header"` and `data-platform-banner-placement="footer"`.
+- Fullscreen mode keeps the header-placement platform banner visible, including `.platform-banner__inner` and the `Development Environment` message.
+- Fullscreen mode hides the footer-placement platform banner with `data-platform-banner-placement="footer"`.
+- Fullscreen mode hides the main site navigation container, `.site-header > div.container.nav`, including the brand/home navigation.
+- Shared fullscreen CSS targets the banner placement attribute and does not target `.platform-banner__inner`.
+- Fullscreen mode hides the character image, renders the badge at 64x64, centers the growing tool name, and keeps the exit icon anchored far right.
+- Narrowed the focused Playwright validation to Tool Display Mode behavior only and renamed it to `ToolDisplayModeSingleLineLayout.spec.mjs`.
+- Removed older PR_26176_001/002 validation assertions and style changes for horizontal accordion color and footer status icon sizing from this branch.
+
+## Changed Files
+- `assets/theme-v2/js/tool-display-mode.js`
+- `assets/theme-v2/css/accordion.css`
+- `assets/theme-v2/css/layout.css`
+- `assets/theme-v2/css/panels.css`
+- `assets/theme-v2/css/status.css`
+- `tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs`
+- `docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_report.md`
+- `docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_branch-validation.md`
+- `docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_validation-lane.md`
+- `docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_requirements-checklist.md`
+- `docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_manual-validation-notes.md`
+- `docs_build/dev/reports/codex_changed_files.txt`
+- `docs_build/dev/reports/codex_review.diff`
+
+## Validation
+- `node --check assets/theme-v2/js/tool-display-mode.js`
+- `node --check tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs`
+- `npx playwright test tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs --workers=1`
+- `git diff --check`
+
+## Notes
+- No individual toolbox pages were modified.
+- The previous fullscreen rule that hid `.platform-banner__inner` was removed.
+- No `PR_26176_006` or `PR_26176_007` branch/artifact was created during this finalization pass.
+- Game Journey completion metrics SQLite/Postgres behavior was not changed; that warning is documented as Golf-owned external storage migration work outside this PR.
+- The focused Playwright run uses deterministic route fixtures for public config, platform banner settings, registry metadata, game-design constants, and minimal game-design repository calls.
diff --git a/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_requirements-checklist.md b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_requirements-checklist.md
new file mode 100644
index 000000000..5fe70f5a0
--- /dev/null
+++ b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_requirements-checklist.md
@@ -0,0 +1,31 @@
+# PR_26176_005 Requirements Checklist
+
+| Requirement | Status | Evidence |
+| --- | --- | --- |
+| Continue only on `PR_26176_005-tool-display-mode-single-line-layout` | PASS | Branch confirmed before cleanup and validation. |
+| Do not create `PR_26176_006` or `PR_26176_007` | PASS | No new branch was created during finalization. |
+| Review modified and untracked files | PASS | Dirty set was reviewed; final dirty set is scoped to PR_26176_005 files. |
+| Remove accidental/unneeded PR_26176_001-004 artifacts | PASS | Untracked PR_26176_001 through PR_26176_004 report files were removed. |
+| Preserve PR_26176_005 reports/specs | PASS | PR_26176_005 report, checklist, validation lane, branch validation, manual notes, diff, changed-files list, and focused spec were updated. |
+| Use shared Theme V2/tool display CSS/JS only unless required | PASS | Runtime changes are limited to shared Theme V2 CSS and `tool-display-mode.js`; no individual toolbox pages changed. |
+| Badge, title, character/image content, and fullscreen/exit icon align in one horizontal row where practical | PASS | Playwright geometry asserts one visual row at the focused desktop width with no overlap or clipping. |
+| Fullscreen/exit icon remains anchored far right | PASS | Shared CSS uses `margin-left: auto`; Playwright verifies right-edge anchoring in normal, fullscreen, and restored states. |
+| Remove old Tool Display Mode chevron | PASS | JS no longer renders `.tool-display-mode__chevron`; obsolete CSS selectors were removed. |
+| Remove `nav.tool-display-mode__navigation-row` from all toolbox pages | PASS | Shared component no longer creates the navigation row. |
+| Remove rendered `Previous: {tool}` and `Next: {tool}` UI | PASS | Playwright and static assertions verify those labels are not rendered by Tool Display Mode. |
+| Remove CSS/JS used solely for the navigation row | PASS | Shared navigation-row, navigation-link, navigation-icon CSS and JS construction were removed. |
+| Normal mode displays both platform banner placements | PASS | Playwright verifies header and footer `data-platform-banner-placement` banners are visible in normal mode. |
+| Fullscreen keeps header-placement platform banner visible | PASS | Playwright verifies the header-placement banner, `.platform-banner__inner`, and `Development Environment` remain visible in focus mode. |
+| Fullscreen hides footer-placement platform banner | PASS | Shared focus CSS targets `[data-platform-banner-placement="footer"]`; Playwright verifies the footer-placement banner is `display: none` in focus mode. |
+| Fullscreen hides main site navigation container | PASS | Shared focus CSS hides `.site-header > div.container.nav`; Playwright verifies it is `display: none` in focus mode. |
+| Do not target `.platform-banner__inner` for fullscreen banner hiding | PASS | Shared status CSS no longer contains a focus-mode rule for `.platform-banner__inner`; the footer placement is targeted by data attribute instead. |
+| Normal mode character image renders at final requested size with aspect ratio preserved | PASS | Playwright verifies the character image is 224px wide with natural aspect ratio. |
+| Normal mode badge is larger | PASS | Playwright verifies the badge is 128x128. |
+| Fullscreen hides character image | PASS | Playwright verifies `.tool-display-mode__character` is not displayed in focus mode. |
+| Fullscreen badge remains larger than the original focus badge | PASS | Playwright verifies the focus badge is 64x64. |
+| Fullscreen badge left, tool name centered/growing, exit icon far right | PASS | Playwright verifies badge left alignment, centered title styling, flex growth, and icon right anchoring. |
+| Preserve fullscreen icon state restoration | PASS | Playwright verifies the icon switches to exit-fullscreen in focus mode and returns to fullscreen after exit. |
+| Do not change Game Journey completion metrics SQLite/Postgres behavior | PASS | No storage/runtime metrics files were changed; warning is documented as Golf-owned external storage migration work. |
+| No unrelated cleanup | PASS | Older accordion color/footer status icon changes were removed from this branch; only PR_26176_005 files remain. |
+| Produce reports under `docs_build/dev/reports/` | PASS | Required PR_26176_005 reports were generated/updated. |
+| Produce repo-structured ZIP under `tmp/` | PASS | `tmp/PR_26176_005-tool-display-mode-single-line-layout_delta.zip` generated after validation. |
diff --git a/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_validation-lane.md b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_validation-lane.md
new file mode 100644
index 000000000..1b1c467c9
--- /dev/null
+++ b/docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_validation-lane.md
@@ -0,0 +1,35 @@
+# PR_26176_005 Validation Lane
+
+## Commands
+
+```powershell
+node --check assets/theme-v2/js/tool-display-mode.js
+node --check tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs
+npx playwright test tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs --workers=1
+git diff --check
+```
+
+## Results
+- `node --check assets/theme-v2/js/tool-display-mode.js`: PASS.
+- `node --check tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs`: PASS.
+- `npx playwright test tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs --workers=1`: PASS, `1 passed`.
+- `git diff --check`: PASS.
+
+## Browser Coverage
+- Loaded `/toolbox/game-design/index.html`.
+- Used deterministic Playwright route fixtures for public config environment banner, platform banner settings, game-design constants, registry metadata, and minimal repository responses.
+- Verified normal mode displays both shared platform banner placements, `data-platform-banner-placement="header"` and `data-platform-banner-placement="footer"`.
+- Verified the header and footer placement banners both carry the `Development Environment` message in normal mode.
+- Verified normal mode keeps `.site-header > div.container.nav` visible.
+- Verified fullscreen mode keeps `header.site-header` and the header-placement platform banner visible, including `.platform-banner__inner` and `Development Environment`.
+- Verified fullscreen mode hides the footer-placement platform banner with `[data-platform-banner-placement="footer"]`.
+- Verified fullscreen mode hides `.site-header > div.container.nav`, including the brand/home navigation.
+- Verified shared status CSS targets `[data-platform-banner-placement="footer"]` and no longer contains a focus-mode rule that hides `.platform-banner__inner`.
+- Verified exiting fullscreen restores the complete platform banner and returns the icon to `fullscreen`.
+- Verified Tool Display Mode summary children are badge, tool name, character image, and fullscreen/exit icon in that order.
+- Verified the fullscreen/exit icon is gold, 2.6x the base layout icon, and anchored to the far right using shared flexbox.
+- Verified normal mode badge is 128x128 and character image is 224px wide with natural aspect ratio.
+- Verified fullscreen mode hides the character image, keeps the badge visible at 64x64, centers/grows the title, and anchors the exit icon far right.
+- Verified the row is a single visual line at the focused desktop width with no overlap or clipping.
+- Verified `nav.tool-display-mode__navigation-row`, `Previous: {tool}`, and `Next: {tool}` are not rendered.
+- Verified shared CSS/JS no longer contain the removed Tool Display Mode navigation/body/description selectors or navigation construction helpers.
diff --git a/docs_build/dev/reports/codex_changed_files.txt b/docs_build/dev/reports/codex_changed_files.txt
index 4cb4ab3d9..4694f15e5 100644
--- a/docs_build/dev/reports/codex_changed_files.txt
+++ b/docs_build/dev/reports/codex_changed_files.txt
@@ -1,27 +1,13 @@
-assets/theme-v2/js/gamefoundry-partials.js
-assets/theme-v2/js/legal-document-page.js
-assets/theme-v2/partials/footer.html
-docs_build/dev/reports/PR_26175_OWNER_054-legal-corrected-package.md
+assets/theme-v2/css/accordion.css
+assets/theme-v2/css/layout.css
+assets/theme-v2/css/panels.css
+assets/theme-v2/css/status.css
+assets/theme-v2/js/tool-display-mode.js
+tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs
+docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_report.md
+docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_branch-validation.md
+docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_validation-lane.md
+docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_requirements-checklist.md
+docs_build/dev/reports/PR_26176_005-tool-display-mode-single-line-layout_manual-validation-notes.md
 docs_build/dev/reports/codex_changed_files.txt
 docs_build/dev/reports/codex_review.diff
-docs_build/dev/reports/coverage_changed_js_guardrail.txt
-docs_build/dev/reports/playwright_v8_coverage_report.txt
-legal/community-guidelines.html
-legal/community-guidelines.md
-legal/cookie-policy.html
-legal/cookie-policy.md
-legal/cookies-policy.html
-legal/copyright-policy.html
-legal/copyright-policy.md
-legal/disclaimer.html
-legal/dmca-policy.html
-legal/dmca-policy.md
-legal/index.html
-legal/index.md
-legal/legal-nav.js
-legal/privacy-policy.html
-legal/privacy-policy.md
-legal/terms.html
-legal/terms-of-service.html
-legal/terms-of-service.md
-tests/playwright/tools/RemainingLegalPages.spec.mjs
\ No newline at end of file
diff --git a/docs_build/dev/reports/codex_review.diff b/docs_build/dev/reports/codex_review.diff
index fdfeac55a..84053786a 100644
Binary files a/docs_build/dev/reports/codex_review.diff and b/docs_build/dev/reports/codex_review.diff differ
diff --git a/tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs b/tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs
new file mode 100644
index 000000000..4655d8079
--- /dev/null
+++ b/tests/playwright/tools/ToolDisplayModeSingleLineLayout.spec.mjs
@@ -0,0 +1,419 @@
+import { expect, test } from "@playwright/test";
+import fs from "node:fs/promises";
+import { startRepoServer } from "../../helpers/playwrightRepoServer.mjs";
+
+const TOOL_IMAGE_FALLBACK = "/assets/theme-v2/images/image-missing.svg";
+
+const GAME_DESIGN_CONSTANTS = {
+  GAME_DESIGN_GAME_TYPES: ["Platformer"],
+  GAME_DESIGN_GENRES: ["Adventure"],
+  GAME_DESIGN_PLAYER_MODES: [{ label: "Single Player", value: "1 Player" }],
+  GAME_DESIGN_PLAY_STYLES: ["Exploration"],
+};
+
+const GAME_DESIGN_SNAPSHOT = {
+  activeDesign: null,
+  activeGame: null,
+  capabilityDemoGames: [],
+  progressHandoff: {
+    currentFocus: "Design",
+    gameProgress: "Not started",
+    progressChecklist: [],
+    publishingProgress: "Not ready",
+    recommendedNextTool: "Game Configuration",
+  },
+  tables: {},
+};
+
+const GAME_DESIGN_VALIDATION = {
+  findings: [],
+  status: "Ready",
+};
+
+const TOOL_REGISTRY_SNAPSHOT = {
+  activeTools: [
+    {
+      displayName: "Build Game",
+      folderName: "build-game",
+      id: "build-game",
+      imageSources: { badge: TOOL_IMAGE_FALLBACK, tool: TOOL_IMAGE_FALLBACK },
+      name: "Build Game",
+      path: "build-game",
+      route: "/toolbox/build-game/index.html",
+    },
+    {
+      displayName: "Game Design",
+      folderName: "game-design",
+      id: "game-design",
+      imageSources: { badge: TOOL_IMAGE_FALLBACK, tool: TOOL_IMAGE_FALLBACK },
+      name: "Game Design",
+      path: "game-design",
+      route: "/toolbox/game-design/index.html",
+    },
+    {
+      displayName: "Game Hub",
+      folderName: "game-hub",
+      id: "game-hub",
+      imageSources: { badge: TOOL_IMAGE_FALLBACK, tool: TOOL_IMAGE_FALLBACK },
+      name: "Game Hub",
+      path: "game-hub",
+      route: "/toolbox/game-hub/index.html",
+    },
+  ],
+  tools: [],
+};
+
+TOOL_REGISTRY_SNAPSHOT.tools = TOOL_REGISTRY_SNAPSHOT.activeTools;
+
+async function openRepoPage(page, pathName) {
+  const server = await startRepoServer();
+  const pageErrors = [];
+
+  page.on("pageerror", (error) => {
+    pageErrors.push(error.message);
+  });
+
+  await page.route("**/api/toolbox/game-design/constants", async (route) => {
+    await route.fulfill({ json: { data: GAME_DESIGN_CONSTANTS, ok: true } });
+  });
+  await page.route("**/api/public/config", async (route) => {
+    await route.fulfill({
+      json: {
+        data: {
+          environmentBanner: {
+            active: true,
+            message: "Development Environment",
+            tone: "warning",
+          },
+          publicConfig: {},
+        },
+        ok: true,
+      },
+    });
+  });
+  await page.route("**/api/platform-settings/banner", async (route) => {
+    await route.fulfill({
+      json: {
+        data: {
+          banner: {
+            active: false,
+            message: "",
+            tone: "info",
+          },
+          diagnostics: { active: false },
+        },
+        ok: true,
+      },
+    });
+  });
+  await page.route("**/api/toolbox/registry/snapshot", async (route) => {
+    await route.fulfill({ json: { data: TOOL_REGISTRY_SNAPSHOT, ok: true } });
+  });
+  await page.route("**/api/toolbox/game-design/repositories", async (route) => {
+    await route.fulfill({ json: { data: { repositoryId: "tool-display-mode-fixture" }, ok: true } });
+  });
+  await page.route("**/api/toolbox/game-design/repositories/**/methods/**", async (route) => {
+    const methodName = decodeURIComponent(route.request().url().split("/methods/").pop() || "");
+    const resultByMethod = {
+      getSnapshot: GAME_DESIGN_SNAPSHOT,
+      openGameContext: { message: "Opened fixture game." },
+      saveDesign: { message: "Saved fixture design." },
+      validateDesign: GAME_DESIGN_VALIDATION,
+    };
+    await route.fulfill({
+      json: {
+        data: { result: resultByMethod[methodName] || null },
+        ok: true,
+      },
+    });
+  });
+
+  await page.goto(`${server.baseUrl}${pathName}`, { waitUntil: "networkidle" });
+  return { pageErrors, server };
+}
+
+function expectNoRuntimeErrors(failures) {
+  expect(failures.pageErrors).toEqual([]);
+}
+
+async function platformBannerSnapshot(page) {
+  await expect(page.locator("header.site-header")).toBeVisible();
+  await expect(page.locator("[data-platform-banner-source='environment-config'][data-platform-banner-placement='header']")).toHaveCount(1);
+  await expect(page.locator("[data-platform-banner-source='environment-config'][data-platform-banner-placement='footer']")).toHaveCount(1);
+  return page.evaluate(() => {
+    const header = document.querySelector("header.site-header");
+    const headerBanner = document.querySelector("[data-platform-banner-source='environment-config'][data-platform-banner-placement='header']");
+    const footerBanner = document.querySelector("[data-platform-banner-source='environment-config'][data-platform-banner-placement='footer']");
+    const headerInner = headerBanner?.querySelector(".platform-banner__inner") || null;
+    const headerMessage = headerBanner?.querySelector(".platform-banner__message") || null;
+    const footerMessage = footerBanner?.querySelector(".platform-banner__message") || null;
+    const nav = header?.querySelector(":scope > .container.nav") || null;
+    const headerBox = header?.getBoundingClientRect();
+    const headerBannerBox = headerBanner?.getBoundingClientRect();
+    const footerBannerBox = footerBanner?.getBoundingClientRect();
+    const headerInnerBox = headerInner?.getBoundingClientRect();
+    const navBox = nav?.getBoundingClientRect();
+    return {
+      footerBannerDisplay: footerBanner ? getComputedStyle(footerBanner).display : "",
+      footerBannerHeight: Number((footerBannerBox?.height || 0).toFixed(2)),
+      footerBannerVisible: Boolean(footerBannerBox && footerBannerBox.width > 0 && footerBannerBox.height > 0),
+      footerMessageText: footerMessage?.textContent?.trim() || "",
+      headerBannerDisplay: headerBanner ? getComputedStyle(headerBanner).display : "",
+      headerBannerHeight: Number((headerBannerBox?.height || 0).toFixed(2)),
+      headerBannerVisible: Boolean(headerBannerBox && headerBannerBox.width > 0 && headerBannerBox.height > 0),
+      headerVisible: Boolean(headerBox && headerBox.width > 0 && headerBox.height > 0),
+      headerInnerDisplay: headerInner ? getComputedStyle(headerInner).display : "",
+      headerInnerHeight: Number((headerInnerBox?.height || 0).toFixed(2)),
+      headerInnerVisible: Boolean(headerInnerBox && headerInnerBox.width > 0 && headerInnerBox.height > 0),
+      headerMessageText: headerMessage?.textContent?.trim() || "",
+      navDisplay: nav ? getComputedStyle(nav).display : "",
+      navVisible: Boolean(navBox && navBox.width > 0 && navBox.height > 0),
+    };
+  });
+}
+
+async function expectPlatformBannerMode(page, { focusMode }) {
+  const snapshot = await platformBannerSnapshot(page);
+  expect(snapshot.headerVisible).toBe(true);
+  expect(snapshot.headerBannerDisplay).toBe("block");
+  expect(snapshot.headerBannerVisible).toBe(true);
+  expect(snapshot.headerMessageText).toBe("Development Environment");
+  expect(snapshot.headerInnerDisplay).toBe("flex");
+  expect(snapshot.headerInnerHeight).toBeGreaterThan(0);
+  expect(snapshot.headerInnerVisible).toBe(true);
+  expect(snapshot.footerMessageText).toBe("Development Environment");
+  if (focusMode) {
+    expect(snapshot.footerBannerDisplay).toBe("none");
+    expect(snapshot.footerBannerHeight).toBe(0);
+    expect(snapshot.footerBannerVisible).toBe(false);
+    expect(snapshot.navDisplay).toBe("none");
+    expect(snapshot.navVisible).toBe(false);
+  } else {
+    expect(snapshot.footerBannerDisplay).toBe("block");
+    expect(snapshot.footerBannerHeight).toBeGreaterThan(0);
+    expect(snapshot.footerBannerVisible).toBe(true);
+    expect(snapshot.navDisplay).toBe("flex");
+    expect(snapshot.navVisible).toBe(true);
+  }
+}
+
+async function toolDisplayControlSnapshot(page) {
+  return page.locator("#toolDisplayMode").evaluate((displayMode) => {
+    const summary = displayMode.querySelector("summary");
+    const badge = summary.querySelector(".tool-display-mode__badge");
+    const fullscreenName = summary.querySelector(".tool-display-mode__fullscreen-name");
+    const character = summary.querySelector(".tool-display-mode__character");
+    const modeIcon = summary.querySelector(".tool-display-mode__mode-icon");
+    const baseIcon = document.createElement("span");
+    baseIcon.className = "layout-icon";
+    baseIcon.style.display = "inline-block";
+    baseIcon.style.position = "absolute";
+    baseIcon.style.visibility = "hidden";
+    const goldProbe = document.createElement("span");
+    goldProbe.style.color = "var(--gold)";
+    goldProbe.style.position = "absolute";
+    goldProbe.style.visibility = "hidden";
+    document.body.append(baseIcon, goldProbe);
+
+    const displayModeBox = displayMode.getBoundingClientRect();
+    const summaryBox = summary.getBoundingClientRect();
+    const badgeBox = badge.getBoundingClientRect();
+    const nameBox = fullscreenName.getBoundingClientRect();
+    const characterBox = character.getBoundingClientRect();
+    const iconBox = modeIcon.getBoundingClientRect();
+    const baseBox = baseIcon.getBoundingClientRect();
+    const summaryStyle = getComputedStyle(summary);
+    const summaryContentRight = summaryBox.right - (parseFloat(summaryStyle.paddingRight) || 0);
+    const summaryContentBox = {
+      bottom: summaryBox.bottom - (parseFloat(summaryStyle.paddingBottom) || 0),
+      left: summaryBox.left + (parseFloat(summaryStyle.paddingLeft) || 0),
+      right: summaryBox.right - (parseFloat(summaryStyle.paddingRight) || 0),
+      top: summaryBox.top + (parseFloat(summaryStyle.paddingTop) || 0),
+    };
+    const characterStyle = getComputedStyle(character);
+    const characterVisible = characterStyle.display !== "none" && characterBox.width > 0 && characterBox.height > 0;
+    const contentBoxes = [badgeBox, nameBox, iconBox];
+    if (characterVisible) {
+      contentBoxes.splice(2, 0, characterBox);
+    }
+    const boxesOverlap = (first, second) => !(
+      first.right <= second.left ||
+      second.right <= first.left ||
+      first.bottom <= second.top ||
+      second.bottom <= first.top
+    );
+    const contentContained = contentBoxes.every((box) => (
+      box.left >= summaryContentBox.left - 1 &&
+      box.right <= summaryContentBox.right + 1 &&
+      box.top >= summaryContentBox.top - 1 &&
+      box.bottom <= summaryContentBox.bottom + 1
+    ));
+    const contentDoesNotOverlap = contentBoxes.every((box, index) => (
+      contentBoxes.slice(index + 1).every((otherBox) => !boxesOverlap(box, otherBox))
+    ));
+    const characterNaturalRatio = character.naturalWidth / character.naturalHeight;
+    const sameVisualRow = contentBoxes.every((box) => {
+      const itemCenter = box.top + (box.height / 2);
+      const iconCenter = iconBox.top + (iconBox.height / 2);
+      return Math.abs(itemCenter - iconCenter) <= 4;
+    });
+    const result = {
+      badgeHeight: Number(badgeBox.height.toFixed(2)),
+      badgeLeftAligned: Math.abs(badgeBox.left - summaryContentBox.left) <= 1,
+      badgeWidth: Number(badgeBox.width.toFixed(2)),
+      characterAfterName: characterBox.left >= nameBox.right - 1,
+      characterDisplay: characterStyle.display,
+      characterHeight: Number(characterBox.height.toFixed(2)),
+      characterNaturalRatio: Number(characterNaturalRatio.toFixed(2)),
+      characterRatio: Number((characterBox.width / characterBox.height).toFixed(2)),
+      characterVisible,
+      characterWidth: Number(characterBox.width.toFixed(2)),
+      chevronCount: summary.querySelectorAll(".tool-display-mode__chevron").length,
+      contentContained,
+      contentDoesNotOverlap,
+      controlRightAligned: Math.abs(summaryBox.right - displayModeBox.right) <= 3,
+      displayModeChildren: Array.from(displayMode.children).map((child) => child.tagName.toLowerCase()),
+      fullscreenNameDisplay: getComputedStyle(fullscreenName).display,
+      fullscreenNameFlexGrow: getComputedStyle(fullscreenName).flexGrow,
+      fullscreenNameJustifyContent: getComputedStyle(fullscreenName).justifyContent,
+      fullscreenNameMinWidth: getComputedStyle(fullscreenName).minWidth,
+      fullscreenNameTextAlign: getComputedStyle(fullscreenName).textAlign,
+      goldColor: getComputedStyle(goldProbe).color,
+      iconColor: getComputedStyle(modeIcon).color,
+      iconFile: modeIcon.dataset.themeIconFile,
+      iconHeightScale: Number((iconBox.height / baseBox.height).toFixed(2)),
+      iconName: modeIcon.dataset.themeIcon,
+      iconAnchoredToSummaryRight: Math.abs(iconBox.right - summaryContentRight) <= 3,
+      iconWidthScale: Number((iconBox.width / baseBox.width).toFixed(2)),
+      navigationRowCount: summary.querySelectorAll(".tool-display-mode__navigation-row").length,
+      navigationTextRemoved: !/Previous:|Next:/.test(summary.textContent || ""),
+      sameVisualRow,
+      summaryDisplay: summaryStyle.display,
+      summaryFlexDirection: summaryStyle.flexDirection,
+      summaryFlexWrap: summaryStyle.flexWrap,
+      summaryChildren: Array.from(summary.children).map((child) => ({
+        className: child.className,
+        tagName: child.tagName.toLowerCase(),
+        themeIcon: child.dataset.themeIcon || "",
+      })),
+      summaryOrder: getComputedStyle(summary).order,
+    };
+
+    baseIcon.remove();
+    goldProbe.remove();
+    return result;
+  });
+}
+
+async function expectToolDisplayControl(page, { badgeSize, characterVisible, characterWidth = 0, focusMode = false, iconFile, iconName }) {
+  await expect(page.locator("#toolDisplayMode summary .tool-display-mode__navigation-row")).toHaveCount(0);
+  await expect(page.locator("#toolDisplayMode summary")).not.toContainText(/Previous:|Next:/);
+  const snapshot = await toolDisplayControlSnapshot(page);
+  expect(snapshot.badgeHeight).toBeCloseTo(badgeSize, 0);
+  expect(snapshot.badgeLeftAligned).toBe(true);
+  expect(snapshot.badgeWidth).toBeCloseTo(badgeSize, 0);
+  expect(snapshot.characterVisible).toBe(characterVisible);
+  if (characterVisible) {
+    expect(snapshot.characterDisplay).toBe("block");
+    expect(snapshot.characterHeight).toBeCloseTo(characterWidth / snapshot.characterNaturalRatio, 0);
+    expect(snapshot.characterRatio).toBeCloseTo(snapshot.characterNaturalRatio, 1);
+    expect(snapshot.characterWidth).toBeCloseTo(characterWidth, 0);
+  } else {
+    expect(snapshot.characterDisplay).toBe("none");
+    expect(snapshot.characterHeight).toBe(0);
+    expect(snapshot.characterWidth).toBe(0);
+  }
+  expect(snapshot.chevronCount).toBe(0);
+  expect(snapshot.contentContained).toBe(true);
+  expect(snapshot.contentDoesNotOverlap).toBe(true);
+  expect(snapshot.controlRightAligned).toBe(true);
+  expect(snapshot.displayModeChildren).toEqual(["summary"]);
+  expect(snapshot.fullscreenNameDisplay).toBe("flex");
+  expect(snapshot.fullscreenNameFlexGrow).toBe("1");
+  expect(snapshot.fullscreenNameMinWidth).toBe("0px");
+  if (focusMode) {
+    expect(snapshot.fullscreenNameJustifyContent).toBe("center");
+    expect(snapshot.fullscreenNameTextAlign).toBe("center");
+  }
+  expect(snapshot.iconColor).toBe(snapshot.goldColor);
+  expect(snapshot.iconFile).toBe(iconFile);
+  expect(snapshot.iconName).toBe(iconName);
+  expect(snapshot.iconAnchoredToSummaryRight).toBe(true);
+  expect(snapshot.iconHeightScale).toBeGreaterThanOrEqual(2.55);
+  expect(snapshot.iconHeightScale).toBeLessThanOrEqual(2.65);
+  expect(snapshot.iconWidthScale).toBeGreaterThanOrEqual(2.55);
+  expect(snapshot.iconWidthScale).toBeLessThanOrEqual(2.65);
+  expect(snapshot.navigationRowCount).toBe(0);
+  expect(snapshot.navigationTextRemoved).toBe(true);
+  expect(snapshot.sameVisualRow).toBe(true);
+  expect(snapshot.summaryDisplay).toBe("flex");
+  expect(snapshot.summaryFlexDirection).toBe("row");
+  expect(snapshot.summaryFlexWrap).toBe("wrap");
+  expect(snapshot.summaryChildren).toEqual([
+    { className: "tool-display-mode__badge", tagName: "img", themeIcon: "" },
+    { className: "tool-display-mode__fullscreen-name", tagName: "span", themeIcon: "" },
+    { className: "tool-display-mode__character", tagName: "img", themeIcon: "" },
+    {
+      className: `theme-icon theme-icon--${iconName} layout-icon tool-display-mode__mode-icon`,
+      tagName: "span",
+      themeIcon: iconName,
+    },
+  ]);
+  expect(snapshot.summaryOrder).toBe("0");
+}
+
+async function expectModeIconUsesAutoMargin() {
+  const css = await fs.readFile("assets/theme-v2/css/panels.css", "utf8");
+  const layoutCss = await fs.readFile("assets/theme-v2/css/layout.css", "utf8");
+  const statusCss = await fs.readFile("assets/theme-v2/css/status.css", "utf8");
+  const js = await fs.readFile("assets/theme-v2/js/tool-display-mode.js", "utf8");
+  expect(css).toMatch(/\.tool-display-mode__mode-icon\s*{[^}]*margin-left:\s*auto;/s);
+  expect(css).not.toMatch(/\.tool-display-mode__(body|identity-row|description|navigation-row|navigation-link|navigation-icon)\b/);
+  expect(layoutCss).toMatch(/body\.tool-focus-mode\s+\.site-header\s*>\s*\.container\.nav\s*{[^}]*display:\s*none\s*!important/s);
+  expect(statusCss).not.toMatch(/tool-focus-mode\s+\.platform-banner__inner/);
+  expect(statusCss).toMatch(/body\.tool-focus-mode\s+\[data-platform-banner-placement="footer"\]\s*{[^}]*display:\s*none\s*!important/s);
+  expect(js).not.toMatch(/tool-display-mode__navigation-row|Previous:|Next:|getToolNavigationTargets|createNavigationControl/);
+}
+
+test("shared Tool Display Mode uses the final single-line layout behavior", async ({ page }) => {
+  const failures = await openRepoPage(page, "/toolbox/game-design/index.html");
+
+  try {
+    await expectPlatformBannerMode(page, { focusMode: false });
+    await expect(page.locator("#toolDisplayMode summary [data-theme-icon='fullscreen']")).toBeVisible();
+    await expectToolDisplayControl(page, {
+      badgeSize: 128,
+      characterVisible: true,
+      characterWidth: 224,
+      iconFile: "gfs-fullscreen.svg",
+      iconName: "fullscreen",
+    });
+    await expectModeIconUsesAutoMargin();
+
+    await page.locator("#toolDisplayMode summary").click();
+    await expect(page.locator("body")).toHaveClass(/tool-focus-mode/);
+    await expectPlatformBannerMode(page, { focusMode: true });
+    await expectToolDisplayControl(page, {
+      badgeSize: 64,
+      characterVisible: false,
+      focusMode: true,
+      iconFile: "gfs-exit-fullscreen.svg",
+      iconName: "exit-fullscreen",
+    });
+
+    await page.locator("#toolDisplayMode summary").click();
+    await expect(page.locator("body")).not.toHaveClass(/tool-focus-mode/);
+    await expectPlatformBannerMode(page, { focusMode: false });
+    await expectToolDisplayControl(page, {
+      badgeSize: 128,
+      characterVisible: true,
+      characterWidth: 224,
+      iconFile: "gfs-fullscreen.svg",
+      iconName: "fullscreen",
+    });
+
+    expectNoRuntimeErrors(failures);
+  } finally {
+    await failures.server.close();
+  }
+});