diff --git a/src/components/MethodChip.css b/src/components/MethodChip.css
index 1c4cb4c..108aebc 100644
--- a/src/components/MethodChip.css
+++ b/src/components/MethodChip.css
@@ -1,12 +1,15 @@
-/* MethodChip.css */
+/* MethodChip.css — Issue #744: mobile responsive layout */
+
+/* ── Base (desktop/tablet) ─────────────────────────────────────────────── */
 .method-chip {
   position: relative;
   display: inline-flex;
   align-items: center;
   justify-content: center;
-  padding: 2px 8px;
-  margin: 2px;
-  min-width: 60px; /* uniform width */
+  padding: 4px 10px;
+  margin: 3px;
+  min-width: 64px; /* uniform width */
+  min-height: 32px;
   border-radius: 4px;
   font-size: 0.75rem;
   font-weight: 600;
@@ -23,9 +26,14 @@
   outline: 2px solid var(--accent);
   outline-offset: 3px;
 }
-.method-icon {
+/* Icon inside the chip.  Note: the component uses "method-chip-icon", not
+   the bare "method-icon" class — fixed in Issue #744. */
+.method-chip-icon {
   margin-right: 4px;
   font-size: 0.85rem;
+  display: inline-flex;
+  align-items: center;
+  flex-shrink: 0;
 }
 .method-tooltip {
   position: absolute;
@@ -52,4 +60,29 @@
   border-width: 5px 5px 0 5px;
   border-style: solid;
   border-color: var(--tooltip-bg, #333) transparent transparent transparent;
+}
+
+/* ── Narrow mobile (≤375 px) — Issue #744 ────────────────────────────────
+   Enlarged tap targets, additional spacing, and responsive wrapping so chips
+   don't overflow the viewport.  WCAG 2.5.5 minimum 44 × 44 px touch target. */
+@media (max-width: 375px) {
+  .method-chip {
+    padding: 10px 14px;
+    margin: 4px;
+    min-width: 44px;
+    min-height: 44px;
+    font-size: 0.8125rem;
+    border-radius: 6px;
+  }
+
+  .method-chip-icon {
+    margin-right: 6px;
+    font-size: 1rem;
+  }
+
+  .method-tooltip {
+    font-size: 0.75rem;
+    padding: 6px 10px;
+    top: 115%;
+  }
 }
\ No newline at end of file
diff --git a/src/components/MethodChip.test.tsx b/src/components/MethodChip.test.tsx
new file mode 100644
index 0000000..3d7e0c7
--- /dev/null
+++ b/src/components/MethodChip.test.tsx
@@ -0,0 +1,101 @@
+// @vitest-environment jsdom
+
+import { cleanup, fireEvent, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it } from "vitest";
+import { MethodChip } from "./MethodChip";
+
+afterEach(cleanup);
+
+describe("MethodChip", () => {
+  it("renders with the HTTP method text uppercased", () => {
+    render(<MethodChip method="get" />);
+    expect(screen.getByLabelText("GET request")).toBeTruthy();
+    expect(screen.getByText("GET")).toBeTruthy();
+  });
+
+  it("renders an icon for the HTTP method", () => {
+    const { container } = render(<MethodChip method="POST" />);
+    const chip = screen.getByLabelText("POST request");
+    const icon = chip.querySelector(".method-chip-icon");
+    expect(icon).toBeTruthy();
+    expect(icon?.querySelector("svg")).toBeTruthy();
+  });
+
+  it("is focusable via tabIndex={0}", () => {
+    render(<MethodChip method="GET" />);
+    const chip = screen.getByLabelText("GET request");
+    expect(chip.getAttribute("tabindex")).toBe("0");
+  });
+
+  it("shows tooltip on focus and hides on blur", () => {
+    render(<MethodChip method="PUT" />);
+    const chip = screen.getByLabelText("PUT request");
+
+    // No tooltip initially
+    expect(screen.queryByRole("tooltip")).toBeNull();
+
+    // Focus should show tooltip
+    fireEvent.focus(chip);
+    expect(screen.getByRole("tooltip")).toBeTruthy();
+
+    // Blur should hide tooltip
+    fireEvent.blur(chip);
+    expect(screen.queryByRole("tooltip")).toBeNull();
+  });
+
+  // ── Mobile layout — CSS-class contract (Issue #744) ─────────────────────
+  //
+  // jsdom does not evaluate @media rules, so we verify the *class contract*:
+  // the correct CSS classes are present so the @media breakpoint rules can
+  // apply in a real browser.
+
+  it("has .method-chip class for responsive styling", () => {
+    render(<MethodChip method="GET" />);
+    const chip = screen.getByLabelText("GET request");
+    expect(chip.classList.contains("method-chip")).toBe(true);
+  });
+
+  it("has the matching method-chip-icon class on the icon wrapper", () => {
+    render(<MethodChip method="GET" />);
+    const chip = screen.getByLabelText("GET request");
+    const icon = chip.querySelector(".method-chip-icon");
+    expect(icon).toBeTruthy();
+  });
+
+  it("renders known HTTP methods with dedicated colors", () => {
+    const methods = ["GET", "POST", "PUT", "DELETE", "PATCH"];
+    methods.forEach((method) => {
+      const { unmount } = render(<MethodChip method={method} />);
+      const chip = screen.getByLabelText(`${method} request`);
+      // Colors should be set via CSS custom properties, never inline hex
+      expect(chip.style.backgroundColor).toMatch(/^var\(--method-/);
+      expect(chip.style.color).toMatch(/^var\(--method-/);
+      unmount();
+    });
+  });
+
+  it("falls back to default colors for unknown methods", () => {
+    render(<MethodChip method="OPTIONS" />);
+    const chip = screen.getByLabelText("OPTIONS request");
+    expect(chip.style.backgroundColor).toBe("var(--surface-soft)");
+    expect(chip.style.color).toBe("var(--text)");
+  });
+
+  it("uses design-token background for GET, POST, PUT, DELETE, PATCH", () => {
+    const checks: Record<string, { bg: string; fg: string }> = {
+      GET: { bg: "var(--method-get-bg)", fg: "var(--method-get-fg)" },
+      POST: { bg: "var(--method-post-bg)", fg: "var(--method-post-fg)" },
+      PUT: { bg: "var(--method-put-bg)", fg: "var(--method-put-fg)" },
+      DELETE: { bg: "var(--method-delete-bg)", fg: "var(--method-delete-fg)" },
+      PATCH: { bg: "var(--method-patch-bg)", fg: "var(--method-patch-fg)" },
+    };
+
+    Object.entries(checks).forEach(([method, colors]) => {
+      const { unmount } = render(<MethodChip method={method} />);
+      const chip = screen.getByLabelText(`${method} request`);
+      expect(chip.style.backgroundColor).toBe(colors.bg);
+      expect(chip.style.color).toBe(colors.fg);
+      unmount();
+    });
+  });
+});