diff --git a/src/components/emoji-picker-design-spec.test.ts b/src/components/emoji-picker-design-spec.test.ts
new file mode 100644
index 00000000..fb403fcd
--- /dev/null
+++ b/src/components/emoji-picker-design-spec.test.ts
@@ -0,0 +1,82 @@
+import { describe, it, expect } from "vitest";
+import { readFileSync } from "fs";
+import { resolve } from "path";
+
+/**
+ * Regression tests for issue #186: UI does not match design spec after PR #185.
+ *
+ * These tests verify that emoji-picker and page-icon source files comply with
+ * the design spec constraints for touch targets, input styling, mobile
+ * visibility, and responsive width.
+ */
+
+function readSource(relativePath: string): string {
+  return readFileSync(resolve(__dirname, relativePath), "utf-8");
+}
+
+describe("emoji-picker design spec compliance", () => {
+  const source = readSource("./emoji-picker.tsx");
+
+  it("emoji buttons have 44px minimum touch target on mobile", () => {
+    // Design spec: "Touch targets: minimum 44px on mobile."
+    // Emoji buttons must use min-h-[44px] and min-w-[44px] for mobile.
+    expect(source).toContain("min-h-[44px]");
+    expect(source).toContain("min-w-[44px]");
+  });
+
+  it("filter input has border per input spec", () => {
+    // Design spec: Inputs should have border-white/[0.06] border.
+    const precedingClass = source.match(
+      /className="[^"]*border border-white\/\[0\.06\][^"]*"[\s\S]*?aria-label="Filter emojis"/
+    );
+    expect(precedingClass).not.toBeNull();
+  });
+
+  it("filter input has focus ring per input spec", () => {
+    // Design spec: Inputs should have ring-2 ring-ring on focus.
+    const inputSection = source.match(
+      /className="[^"]*"[\s\S]*?aria-label="Filter emojis"/
+    );
+    expect(inputSection).not.toBeNull();
+    expect(inputSection![0]).toContain("focus:ring-2");
+    expect(inputSection![0]).toContain("focus:ring-ring");
+  });
+
+  it("picker uses responsive width to avoid mobile clipping", () => {
+    // Design spec: "No horizontal scroll on any breakpoint."
+    // The picker must not use a fixed w-72 without a mobile-responsive alternative.
+    expect(source).toContain("sm:w-72");
+    // Must have a viewport-relative width for mobile
+    expect(source).toMatch(/w-\[calc\(100vw/);
+  });
+});
+
+describe("page-icon design spec compliance", () => {
+  const source = readSource("./page-icon.tsx");
+
+  it("page icon button has 44px minimum touch target on mobile", () => {
+    // Design spec: "Touch targets: minimum 44px on mobile."
+    expect(source).toContain("min-h-[44px]");
+    expect(source).toContain("min-w-[44px]");
+  });
+
+  it("add-icon button is visible on mobile (not hover-only)", () => {
+    // Design spec: Touch targets must be accessible on mobile.
+    // The button container must not rely solely on group-hover for visibility.
+    // It should use max-sm:opacity-100 or similar to be visible on touch devices.
+    expect(source).toContain("max-sm:opacity-100");
+  });
+
+  it("add-icon button has 44px minimum touch target on mobile", () => {
+    // The "Add icon" button must meet the 44px minimum on mobile.
+    const addIconSection = source.match(
+      /aria-label="Add page icon"[\s\S]{0,50}/
+    );
+    expect(addIconSection).not.toBeNull();
+
+    const classSection = source.match(
+      /className="[^"]*min-h-\[44px\][^"]*"[\s\S]*?aria-label="Add page icon"/
+    );
+    expect(classSection).not.toBeNull();
+  });
+});
diff --git a/src/components/emoji-picker.tsx b/src/components/emoji-picker.tsx
index 8b5a0d48..f9e7de2e 100644
--- a/src/components/emoji-picker.tsx
+++ b/src/components/emoji-picker.tsx
@@ -181,7 +181,7 @@ export function EmojiPicker({
       {open && (
         <div
           ref={floatingRef}
-          className="fixed z-50 w-72 rounded-sm border border-white/[0.06] bg-popover p-2 shadow-md"
+          className="fixed z-50 w-[calc(100vw-16px)] rounded-sm border border-white/[0.06] bg-popover p-2 shadow-md sm:w-72"
           role="dialog"
           aria-label="Emoji picker"
         >
@@ -191,7 +191,7 @@ export function EmojiPicker({
             value={filter}
             onChange={(e) => setFilter(e.target.value)}
             placeholder="Filter..."
-            className="mb-2 w-full bg-muted px-2 py-1 text-sm text-foreground placeholder:text-muted-foreground outline-none"
+            className="mb-2 h-9 w-full border border-white/[0.06] bg-muted px-2 py-1 text-sm text-foreground placeholder:text-muted-foreground focus:ring-2 focus:ring-ring focus:outline-none"
             aria-label="Filter emojis"
           />
           {hasIcon && onRemove && (
@@ -208,12 +208,12 @@ export function EmojiPicker({
                 <div className="px-1 py-1 text-xs tracking-widest uppercase text-white/30">
                   {category.label}
                 </div>
-                <div className="grid grid-cols-8 gap-0.5">
+                <div className="grid grid-cols-6 gap-0.5 sm:grid-cols-8">
                   {category.emojis.map((emoji) => (
                     <button
                       key={emoji}
                       onClick={() => handleSelect(emoji)}
-                      className="flex h-8 w-8 items-center justify-center text-lg hover:bg-white/[0.04]"
+                      className="flex min-h-[44px] min-w-[44px] items-center justify-center text-lg hover:bg-white/[0.04] sm:min-h-8 sm:min-w-8"
                       aria-label={`Select ${emoji}`}
                     >
                       {emoji}
diff --git a/src/components/page-icon.tsx b/src/components/page-icon.tsx
index e609635d..cf077584 100644
--- a/src/components/page-icon.tsx
+++ b/src/components/page-icon.tsx
@@ -55,7 +55,7 @@ export function PageIcon({ pageId, initialIcon }: PageIconProps) {
           hasIcon
         >
           <button
-            className="flex h-10 w-10 items-center justify-center rounded-sm text-4xl leading-none hover:bg-white/[0.04]"
+            className="flex min-h-[44px] min-w-[44px] items-center justify-center rounded-sm text-4xl leading-none hover:bg-white/[0.04] sm:min-h-10 sm:min-w-10"
             aria-label={`Page icon: ${icon}. Click to change`}
           >
             {icon}
@@ -66,7 +66,7 @@ export function PageIcon({ pageId, initialIcon }: PageIconProps) {
   }
 
   return (
-    <div className="mb-1 opacity-0 group-hover/page-header:opacity-100">
+    <div className="mb-1 max-sm:opacity-100 opacity-0 group-hover/page-header:opacity-100">
       <EmojiPicker
         open={open}
         onOpenChange={setOpen}
@@ -75,7 +75,7 @@ export function PageIcon({ pageId, initialIcon }: PageIconProps) {
         hasIcon={false}
       >
         <button
-          className="flex h-7 items-center gap-1 rounded-sm px-1.5 text-xs text-muted-foreground hover:bg-white/[0.04]"
+          className="flex min-h-[44px] items-center gap-1 rounded-sm px-1.5 text-xs text-muted-foreground hover:bg-white/[0.04] sm:min-h-7"
           aria-label="Add page icon"
         >
           <SmilePlus className="h-3.5 w-3.5" />