diff --git a/apps/landing/src/components/shared/ApiKeyWidget/apikey-widget.tsx b/apps/landing/src/components/shared/ApiKeyWidget/apikey-widget.tsx
index 7e21611..9c85332 100644
--- a/apps/landing/src/components/shared/ApiKeyWidget/apikey-widget.tsx
+++ b/apps/landing/src/components/shared/ApiKeyWidget/apikey-widget.tsx
@@ -15,7 +15,7 @@
  * Must be used within ApiKeyProvider context
  */
 
-import { useEffect, useRef } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import { useApiKey } from './apikey-context';
 
 export function ApiKeyWidget() {
@@ -35,6 +35,22 @@ export function ApiKeyWidget() {
 
   const containerRef = useRef<HTMLDivElement>(null);
   const inputRef = useRef<HTMLInputElement>(null);
+  const [isMobileContext, setIsMobileContext] = useState(false);
+
+  // Detect mobile context (inside mobile dropdown menu)
+  useEffect(() => {
+    const checkContext = () => {
+      if (containerRef.current) {
+        // Check if ancestor has md:hidden class (mobile menu)
+        const mobileMenu = containerRef.current.closest('.md\\:hidden');
+        setIsMobileContext(mobileMenu !== null);
+      }
+    };
+
+    checkContext();
+    window.addEventListener('resize', checkContext);
+    return () => window.removeEventListener('resize', checkContext);
+  }, []);
 
   // Click outside to close
   useEffect(() => {
@@ -72,13 +88,29 @@ export function ApiKeyWidget() {
   };
 
   return (
-    <div ref={containerRef} className="relative h-full flex items-center">
-      {!ui.expanded ? (
-        // COLLAPSED STATE - Inline badge in nav
+    <>
+      {/* Backdrop for mobile expanded state */}
+      {ui.expanded && isMobileContext && (
+        <div
+          className="fixed inset-0 bg-black/50 z-40"
+          onClick={() => setExpanded(false)}
+          aria-label="Close API key details"
+        />
+      )}
+
+      <div ref={containerRef} className={isMobileContext ? "relative" : "relative h-full flex items-center"}>
+        {/* COLLAPSED STATE - Always rendered to maintain layout space */}
         <button
           onClick={() => setExpanded(true)}
-          className="group px-3 py-2 bg-slate-900/95 backdrop-blur-sm border border-slate-700 rounded-lg hover:border-purple-500/50 transition-all h-10 flex items-center"
+          className={`group px-3 bg-slate-900/95 backdrop-blur-sm border border-slate-700 rounded-lg hover:border-purple-500/50 transition-all flex items-center ${
+            isMobileContext
+              ? 'w-auto max-w-full py-2.5 h-11' // Mobile: auto-width, larger touch target
+              : 'py-2 h-10' // Desktop: original size
+          } ${
+            ui.expanded && isMobileContext ? 'opacity-50 pointer-events-none' : '' // Fade when expanded on mobile
+          }`}
           aria-label="Expand API key details"
+          disabled={ui.expanded}
         >
           <div className="flex items-center gap-2">
             <div
@@ -104,9 +136,14 @@ export function ApiKeyWidget() {
             </svg>
           </div>
         </button>
-      ) : (
-        // EXPANDED STATE - Popup dropdown
-        <div className="absolute top-0 right-0 w-96 p-5 bg-slate-900/95 backdrop-blur-sm border border-slate-700 rounded-xl shadow-2xl z-50 animate-in fade-in slide-in-from-top-2 duration-200">
+
+        {/* EXPANDED STATE - Rendered as overlay when expanded */}
+        {ui.expanded && (
+          <div className={`bg-slate-900/95 backdrop-blur-sm border border-slate-700 rounded-xl shadow-2xl animate-in fade-in duration-200 ${
+            isMobileContext
+              ? 'absolute top-0 left-0 right-0 p-4 z-50' // Mobile: absolute positioned, top-aligned
+              : 'absolute top-0 right-0 w-96 p-5 z-50' // Desktop: absolute positioned
+          }`}>
           {/* Header */}
           <div className="flex items-start justify-between mb-4">
             <div>
@@ -244,6 +281,7 @@ export function ApiKeyWidget() {
           )}
         </div>
       )}
-    </div>
+      </div>
+    </>
   );
 }
diff --git a/apps/landing/src/components/shared/SubsectionNav.tsx b/apps/landing/src/components/shared/SubsectionNav.tsx
index b133450..0274f83 100644
--- a/apps/landing/src/components/shared/SubsectionNav.tsx
+++ b/apps/landing/src/components/shared/SubsectionNav.tsx
@@ -141,23 +141,37 @@ export const SubsectionNav = ({ items, currentPath, leftSlot, rightSlot }: Subse
       {/* Mobile Menu Overlay */}
       {mobileMenuOpen && (
         <div className="md:hidden border-t border-white/10 bg-slate-900/95 backdrop-blur-sm">
-          <div className="px-6 py-4 space-y-2">
-            {items.map((item) => {
-              const active = isActive(item.href);
-              return (
-                <a
-                  key={item.href}
-                  href={item.href}
-                  onClick={() => setMobileMenuOpen(false)}
-                  className={`
-                    block px-4 py-3 rounded-lg text-sm font-medium transition-colors
-                    ${active ? 'bg-purple-500/10 text-purple-400' : 'text-gray-400 hover:text-white hover:bg-white/5'}
-                  `}
-                >
-                  {item.label}
-                </a>
-              );
-            })}
+          <div className="px-6 py-4">
+            {/* ApiKeyWidget - Mobile */}
+            {rightSlot && (
+              <>
+                <div className="flex justify-end mb-3">
+                  {rightSlot}
+                </div>
+                {/* Visual separator */}
+                <div className="border-t border-white/10 mb-3" />
+              </>
+            )}
+
+            {/* Navigation items */}
+            <div className="space-y-2">
+              {items.map((item) => {
+                const active = isActive(item.href);
+                return (
+                  <a
+                    key={item.href}
+                    href={item.href}
+                    onClick={() => setMobileMenuOpen(false)}
+                    className={`
+                      block px-4 py-3 rounded-lg text-sm font-medium transition-colors
+                      ${active ? 'bg-purple-500/10 text-purple-400' : 'text-gray-400 hover:text-white hover:bg-white/5'}
+                    `}
+                  >
+                    {item.label}
+                  </a>
+                );
+              })}
+            </div>
           </div>
         </div>
       )}