diff --git a/ui/src/pages/accounts.tsx b/ui/src/pages/accounts.tsx
index 877b04b4..71de35b2 100644
--- a/ui/src/pages/accounts.tsx
+++ b/ui/src/pages/accounts.tsx
@@ -55,7 +55,7 @@ export function AccountsPage() {
 
   return (
     <>
-      <div className="h-[calc(100vh-100px)] hidden lg:flex">
+      <div className="hidden h-full min-h-0 lg:flex">
         {/* Left action column */}
         <div className="w-80 border-r flex flex-col bg-muted/20 shrink-0">
           <div className="p-4 border-b bg-background space-y-2">
diff --git a/ui/src/pages/api.tsx b/ui/src/pages/api.tsx
index b1474d57..028121c3 100644
--- a/ui/src/pages/api.tsx
+++ b/ui/src/pages/api.tsx
@@ -206,7 +206,7 @@ export function ApiPage() {
   };
 
   return (
-    <div className="h-[calc(100vh-100px)] flex flex-col">
+    <div className="flex h-full min-h-0 flex-col overflow-hidden">
       <OpenRouterBanner onCreateClick={() => setCreateDialogOpen(true)} />
       <div className="flex-1 flex min-h-0">
         <div className="w-80 border-r flex flex-col bg-muted/30">
diff --git a/ui/src/pages/claude-extension.tsx b/ui/src/pages/claude-extension.tsx
index 00bed2c0..c17057ac 100644
--- a/ui/src/pages/claude-extension.tsx
+++ b/ui/src/pages/claude-extension.tsx
@@ -405,7 +405,7 @@ export function ClaudeExtensionPage() {
   }
 
   return (
-    <div className="flex h-[calc(100vh-100px)] min-h-0">
+    <div className="flex h-full min-h-0 overflow-hidden">
       <div className="flex w-[348px] shrink-0 flex-col border-r bg-muted/30 xl:w-[372px]">
         <div className="border-b bg-background p-4">
           <div className="flex items-start justify-between gap-3">
diff --git a/ui/src/pages/cliproxy-ai-providers.tsx b/ui/src/pages/cliproxy-ai-providers.tsx
index 78deca16..37998ca0 100644
--- a/ui/src/pages/cliproxy-ai-providers.tsx
+++ b/ui/src/pages/cliproxy-ai-providers.tsx
@@ -1462,7 +1462,7 @@ export function CliproxyAiProvidersPage() {
 
   if (isLoading) {
     return (
-      <div className="flex h-[calc(100vh-100px)] min-h-0">
+      <div className="flex h-full min-h-0 overflow-hidden">
         <Skeleton className="h-full w-80 rounded-none" />
         <Skeleton className="h-full flex-1 rounded-none" />
       </div>
@@ -1476,7 +1476,7 @@ export function CliproxyAiProvidersPage() {
         : 'Failed to load CLIProxy AI providers. Check the local server and try again.';
 
     return (
-      <div className="flex h-[calc(100vh-100px)] min-h-0 items-center justify-center bg-muted/10 p-6">
+      <div className="flex h-full min-h-0 items-center justify-center bg-muted/10 p-6">
         <div className="w-full max-w-2xl rounded-xl border bg-card p-6 shadow-sm">
           <div className="flex items-start gap-4">
             <div className="flex h-11 w-11 items-center justify-center rounded-lg bg-destructive/10">
@@ -1549,7 +1549,7 @@ export function CliproxyAiProvidersPage() {
     </div>
   );
   return (
-    <div className="flex h-[calc(100vh-100px)] min-h-0">
+    <div className="flex h-full min-h-0 overflow-hidden">
       <div className="flex w-80 flex-col border-r bg-muted/30">
         <div className="border-b bg-background p-4">
           <div className="mb-1 flex items-center justify-between">
diff --git a/ui/src/pages/cliproxy-control-panel.tsx b/ui/src/pages/cliproxy-control-panel.tsx
index 80cfa80e..776c33ca 100644
--- a/ui/src/pages/cliproxy-control-panel.tsx
+++ b/ui/src/pages/cliproxy-control-panel.tsx
@@ -8,7 +8,7 @@ import { ControlPanelEmbed } from '@/components/cliproxy/control-panel-embed';
 
 export function CliproxyControlPanelPage() {
   return (
-    <div className="h-[calc(100vh-100px)] flex flex-col">
+    <div className="flex h-full min-h-0 flex-col overflow-hidden">
       <ControlPanelEmbed />
     </div>
   );
diff --git a/ui/src/pages/cliproxy.tsx b/ui/src/pages/cliproxy.tsx
index f1d8c557..ce4e2a05 100644
--- a/ui/src/pages/cliproxy.tsx
+++ b/ui/src/pages/cliproxy.tsx
@@ -338,7 +338,7 @@ export function CliproxyPage() {
   };
 
   return (
-    <div className="h-[calc(100vh-100px)] flex">
+    <div className="flex h-full min-h-0 overflow-hidden">
       {/* Left Sidebar */}
       <div className="w-80 border-r flex flex-col bg-muted/30">
         {/* Header */}
diff --git a/ui/src/pages/copilot.tsx b/ui/src/pages/copilot.tsx
index 211a240b..23a58578 100644
--- a/ui/src/pages/copilot.tsx
+++ b/ui/src/pages/copilot.tsx
@@ -116,7 +116,7 @@ export function CopilotPage() {
   } = useCopilot();
 
   return (
-    <div className="h-[calc(100vh-100px)] flex">
+    <div className="flex h-full min-h-0 overflow-hidden">
       {/* Left Sidebar - Status Overview */}
       <div className="w-80 border-r flex flex-col bg-muted/30 shrink-0">
         {/* Header */}
diff --git a/ui/src/pages/cursor.tsx b/ui/src/pages/cursor.tsx
index 2c4b7679..e788ecb0 100644
--- a/ui/src/pages/cursor.tsx
+++ b/ui/src/pages/cursor.tsx
@@ -633,7 +633,7 @@ export function CursorPage() {
 
   return (
     <>
-      <div className="h-[calc(100vh-100px)] flex">
+      <div className="flex h-full min-h-0 overflow-hidden">
         <div className="w-80 border-r flex flex-col bg-muted/30 shrink-0">
           <div className="p-4 border-b bg-background">
             <div className="flex items-center justify-between mb-1">
diff --git a/ui/src/pages/droid.tsx b/ui/src/pages/droid.tsx
index 382791c3..0166ab23 100644
--- a/ui/src/pages/droid.tsx
+++ b/ui/src/pages/droid.tsx
@@ -694,7 +694,7 @@ export function DroidPage() {
   };
 
   return (
-    <div className="h-[calc(100vh-100px)] overflow-hidden">
+    <div className="h-full min-h-0 overflow-hidden">
       <PanelGroup direction="horizontal" className="h-full">
         <Panel defaultSize={45} minSize={35}>
           <div className="h-full border-r bg-muted/20">{renderOverview()}</div>
diff --git a/ui/src/pages/settings/index.tsx b/ui/src/pages/settings/index.tsx
index 57da2d80..bb317ff9 100644
--- a/ui/src/pages/settings/index.tsx
+++ b/ui/src/pages/settings/index.tsx
@@ -121,7 +121,7 @@ function SettingsPageInner() {
   };
 
   return (
-    <div className="h-[calc(100vh-100px)]">
+    <div className="h-full min-h-0">
       {/* Mobile View - Stacked vertically */}
       <div className="md:hidden h-full flex flex-col">
         <div className="border-b bg-background p-4">
diff --git a/ui/src/pages/updates.tsx b/ui/src/pages/updates.tsx
index 770c3d61..1a4048db 100644
--- a/ui/src/pages/updates.tsx
+++ b/ui/src/pages/updates.tsx
@@ -102,7 +102,7 @@ export function UpdatesPage() {
   );
 
   return (
-    <div className="h-[calc(100vh-100px)] flex overflow-hidden">
+    <div className="flex h-full min-h-0 overflow-hidden">
       <div className="w-80 border-r bg-muted/30 flex flex-col overflow-hidden">
         <div className="p-4 border-b bg-background space-y-3">
           <div className="space-y-1">
diff --git a/ui/tests/unit/ui/pages/dashboard-page-height-contract.test.ts b/ui/tests/unit/ui/pages/dashboard-page-height-contract.test.ts
new file mode 100644
index 00000000..170f3890
--- /dev/null
+++ b/ui/tests/unit/ui/pages/dashboard-page-height-contract.test.ts
@@ -0,0 +1,38 @@
+import { readFileSync } from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+const testDir = path.dirname(fileURLToPath(import.meta.url));
+const projectRoot = path.resolve(testDir, '../../../../');
+
+const layoutManagedRouteFiles = [
+  'src/pages/index.tsx',
+  'src/pages/analytics/index.tsx',
+  'src/pages/updates.tsx',
+  'src/pages/api.tsx',
+  'src/pages/cliproxy.tsx',
+  'src/pages/cliproxy-ai-providers.tsx',
+  'src/pages/cliproxy-control-panel.tsx',
+  'src/pages/copilot.tsx',
+  'src/pages/cursor.tsx',
+  'src/pages/claude-extension.tsx',
+  'src/pages/droid.tsx',
+  'src/pages/accounts.tsx',
+  'src/pages/settings/index.tsx',
+  'src/pages/health.tsx',
+  'src/pages/shared.tsx',
+] as const;
+
+const forbiddenViewportHeightPattern = /\b(?:h-screen|min-h-screen)\b|calc\(100(?:d|l|s)?vh/i;
+
+describe('dashboard route height contract', () => {
+  it.each(layoutManagedRouteFiles)(
+    '%s relies on the shared layout for viewport height',
+    (relativePath) => {
+      const source = readFileSync(path.join(projectRoot, relativePath), 'utf8');
+
+      expect(source).not.toMatch(forbiddenViewportHeightPattern);
+    }
+  );
+});