diff --git a/Cargo.toml b/Cargo.toml
index 7770689..4246bfa 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -64,6 +64,6 @@ gloo-timers = { version = "0.3", features = ["futures"] }
 tracing = "0.1"
 tracing-wasm = "0.2"
 console_error_panic_hook = "0.1"
-web-sys = { version = "0.3", features = ["Window", "Location"] }
+web-sys = { version = "0.3", features = ["Window", "Location", "MediaQueryList", "MediaQueryListEvent"] }
 js-sys = "0.3"
 futures = "0.3"
diff --git a/DESIGN.md b/DESIGN.md
index aad49b7..7bd540b 100644
--- a/DESIGN.md
+++ b/DESIGN.md
@@ -224,6 +224,18 @@ by default.
 
 ## Layout
 
+### Breakpoints
+
+- **Mobile:** < 480px. Single column, collapsed nav, card view, secondary
+  row details hidden.
+- **Tablet:** 480–767px. Compact spacing, dashboard forced to card view.
+- **Desktop-small:** 768–1023px. Full nav and table restored.
+- **Desktop:** ≥ 1024px. Full experience (content max 1280px).
+
+Media queries use these exact pixel values — CSS custom properties cannot
+be used inside `@media`, so the values live in `style.css` under
+"Responsive breakpoints" and this section documents them.
+
 ### Grid
 
 - **Max width:** 1280px, centered.
diff --git a/ROADMAP.md b/ROADMAP.md
index e1965b6..2e791a8 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -134,15 +134,21 @@ dark-first/sky-blue identity was reverted in `294d214`; needs a redo.
 Most developers check dashboards on desktop, but a quick phone check should
 work too.
 
-- [ ] **Breakpoint system.** Mobile, tablet, desktop-small, desktop.
-- [ ] **Table → card fallback.** The sortable table is unusable on small
-  screens. Force card view below tablet width.
-- [ ] **Responsive navigation.** Top nav on desktop; collapsed menu on
-  mobile.
-- [ ] **Touch targets.** All interactive elements meet WCAG AA sizing.
+- [x] **Breakpoint system.** Mobile (<480px), tablet (480–767px),
+  desktop-small (768–1023px), desktop (≥1024px). Documented in DESIGN.md
+  "Layout > Breakpoints", with the pixel values written out at each
+  `@media` query in `style.css`.
+- [x] **Table → card fallback.** The dashboard watches
+  `matchMedia("(max-width: 767px)")`, forces the card view below the
+  tablet breakpoint and hides the Table/Cards toggle.
+- [x] **Responsive navigation.** Hamburger button below 768px; the nav
+  links become a dropdown panel under the sticky header and close on
+  selection. Theme toggle + rate badge stay in the top row.
+- [x] **Touch targets.** `@media (pointer: coarse)` gives interactive
+  elements a 44px minimum height; desktop density is untouched.
 
 **Acceptance:** usable from phone to ultrawide; table auto-converts to
-cards on mobile.
+cards on mobile. ✅ Phase complete.
 
 ### 5. Keyboard navigation
 
diff --git a/crates/app/src/app.rs b/crates/app/src/app.rs
index ec07137..4ececfd 100644
--- a/crates/app/src/app.rs
+++ b/crates/app/src/app.rs
@@ -37,6 +37,10 @@ pub fn App() -> impl IntoView {
 
   let settings = expect_context::<SettingsState>();
 
+  // Mobile nav: the links collapse behind this menu button below the tablet
+  // breakpoint (see DESIGN.md "Breakpoints").
+  let (menu_open, set_menu_open) = signal(false);
+
   // Reflect the theme onto the document root so `:root[data-theme]` CSS applies.
   let theme_attr = move || settings.theme.get().as_attr();
   leptos::prelude::Effect::new(move |_| {
@@ -67,11 +71,15 @@ pub fn App() -> impl IntoView {
                                   </svg>
                                   "Lepo"
                               </a>
-                              <nav class="primary-nav-links">
+                              <nav
+                                  class="primary-nav-links"
+                                  class:nav-open=move || menu_open.get()
+                              >
                                   <a
                                       href="/"
                                       class="nav-link"
                                       class:active=move || location.pathname.get() == "/"
+                                      on:click=move |_| { set_menu_open.set(false); }
                                   >
                                       "Dashboard"
                                   </a>
@@ -79,6 +87,7 @@ pub fn App() -> impl IntoView {
                                       href="/settings"
                                       class="nav-link"
                                       class:active=move || location.pathname.get() == "/settings"
+                                      on:click=move |_| { set_menu_open.set(false); }
                                   >
                                       "Settings"
                                   </a>
@@ -108,6 +117,18 @@ pub fn App() -> impl IntoView {
                                   </button>
                                   <RateLimitBadge/>
                               </div>
+                              <button
+                                  class="nav-menu-btn"
+                                  aria-label="Toggle navigation"
+                                  aria-expanded=move || menu_open.get()
+                                  on:click=move |_| {
+                                      set_menu_open.update(|open| *open = !*open);
+                                  }
+                              >
+                                  <svg viewBox="0 0 24 24" width="22" height="22" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round">
+                                      <path d="M4 7h16M4 12h16M4 17h16"/>
+                                  </svg>
+                              </button>
                           </div>
                       </header>
                   }
diff --git a/crates/app/src/pages/dashboard.rs b/crates/app/src/pages/dashboard.rs
index 57b102e..9ae824b 100644
--- a/crates/app/src/pages/dashboard.rs
+++ b/crates/app/src/pages/dashboard.rs
@@ -44,6 +44,25 @@ pub fn DashboardPage() -> impl IntoView {
 
   // View / filter / sort state.
   let (view_mode, set_view_mode) = signal(ViewMode::Table);
+
+  // Below the tablet breakpoint (767px, DESIGN.md "Breakpoints") the table
+  // is unusable, so the dashboard forces the card view and the toggle is
+  // hidden via CSS. Resizing back up restores the user's choice.
+  let (is_compact, set_is_compact) = signal(false);
+  leptos::prelude::Effect::new(move |_| {
+    if is_compact.get() {
+      set_view_mode.set(ViewMode::Cards);
+    }
+  });
+  if let Ok(Some(mql)) = window().match_media("(max-width: 767px)") {
+    set_is_compact.set(mql.matches());
+    let listener = mql.clone();
+    let cb = Closure::<dyn FnMut()>::new(move || set_is_compact.set(listener.matches()));
+    let _ = mql.add_event_listener_with_callback("change", cb.as_ref().unchecked_ref());
+    // The closure is not Send+Sync, so it can't be stored for on_cleanup;
+    // forget() keeps it alive for the page lifetime (one per mount).
+    cb.forget();
+  }
   let (query, set_query) = signal(String::new());
   let (sort_key, set_sort_key) = signal(SortKey::Name);
   let (sort_asc, set_sort_asc) = signal(true);
diff --git a/crates/app/src/style.css b/crates/app/src/style.css
index 9739686..159d072 100644
--- a/crates/app/src/style.css
+++ b/crates/app/src/style.css
@@ -86,6 +86,15 @@
   --content-max: 1280px;
 }
 
+/* ---------- Responsive breakpoints ----------
+   Documented in DESIGN.md "Layout > Breakpoints":
+     mobile       < 480px
+     tablet       480-767px
+     desktop-small 768-1023px
+     desktop      >= 1024px
+   CSS custom properties can't be used inside @media, so these exact
+   pixel values are repeated at each query below. */
+
 /* Dark theme overrides */
 :root[data-theme="dark"] {
   --colors-canvas: #1b1b18;
@@ -165,6 +174,7 @@ a:hover {
   border-bottom: 1px solid var(--colors-hairline);
 }
 .primary-nav-inner {
+  position: relative;
   display: flex;
   align-items: center;
   gap: var(--spacing-xl);
@@ -234,6 +244,22 @@ a:hover {
   gap: var(--spacing-sm);
   padding-left: var(--spacing-md);
 }
+.nav-menu-btn {
+  display: none;
+  align-items: center;
+  justify-content: center;
+  width: 40px;
+  height: 40px;
+  border: none;
+  border-radius: var(--rounded-sm);
+  background: transparent;
+  color: var(--colors-ink);
+  cursor: pointer;
+  transition: background 120ms ease;
+}
+.nav-menu-btn:hover {
+  background: var(--colors-surface-card);
+}
 
 .app-main {
   flex: 1 1 auto;
@@ -824,9 +850,7 @@ a:hover {
   background: var(--colors-canvas);
   color: var(--colors-ink);
   box-shadow: var(--shadow-sm);
-}
-
-.summary-strip {
+}.summary-strip {
   display: grid;
   grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
   gap: var(--spacing-md);
@@ -1020,19 +1044,103 @@ a:hover {
   margin-bottom: var(--spacing-md);
 }
 
-/* ---------- Responsive ---------- */
-@media (max-width: 768px) {
+/* ---------- Responsive: tablet (max-width: 767px) ---------- */
+@media (max-width: 767px) {
   .app-main {
-    padding: var(--spacing-xl) var(--spacing-md) var(--spacing-section);
+    padding: var(--spacing-lg) var(--spacing-md) var(--spacing-xxl);
   }
-  .primary-nav {
-    padding: 0 var(--spacing-md);
-    gap: var(--spacing-md);
+  .heading-lg {
+    font-size: 28px;
   }
   .repo-grid {
     grid-template-columns: 1fr;
   }
-  .heading-lg {
-    font-size: 32px;
+  .view-toggle {
+    display: none;
+  }
+  .nav-menu-btn {
+    display: inline-flex;
+  }
+  .primary-nav-inner {
+    padding: 0 var(--spacing-md);
+    gap: var(--spacing-sm);
+  }
+  .primary-nav-rate {
+    padding-left: 0;
+    gap: var(--spacing-xs);
+  }
+  .primary-nav-links {
+    display: none;
+    position: absolute;
+    top: var(--nav-height);
+    left: 0;
+    right: 0;
+    flex-direction: column;
+    align-items: stretch;
+    background: var(--colors-canvas);
+    border-bottom: 1px solid var(--colors-hairline);
+    padding: var(--spacing-sm) var(--spacing-md) var(--spacing-md);
+    gap: var(--spacing-xxs);
+  }
+  .primary-nav-links.nav-open {
+    display: flex;
+  }
+  .nav-link.active::after {
+    display: none;
+  }
+  .row {
+    flex-wrap: wrap;
+    gap: var(--spacing-sm);
+  }
+  .row-updated {
+    display: none;
+  }
+  .load-more {
+    width: 100%;
+  }
+}
+
+/* ---------- Responsive: mobile (max-width: 479px) ---------- */
+@media (max-width: 479px) {
+  .page-header {
+    flex-direction: column;
+    align-items: flex-start;
+  }
+  .dash-toolbar {
+    align-items: stretch;
+  }
+  .summary-strip {
+    grid-template-columns: repeat(2, 1fr);
+  }
+  .row-comments {
+    display: none;
+  }
+  .page-login {
+    margin-top: var(--spacing-xxl);
+  }
+}
+
+/* ---------- Touch targets: coarse pointers (see DESIGN.md) ----------
+   WCAG AA minimum target size is 24px; 44px is the comfortable standard
+   for touch screens, applied only where the primary pointer is coarse so
+   desktop density is untouched. */
+@media (pointer: coarse) {
+  .nav-link,
+  .filter-chip,
+  .view-toggle button,
+  .theme-toggle,
+  .nav-menu-btn,
+  .load-more,
+  .button-primary,
+  .button-secondary,
+  .button-tertiary,
+  .text-input {
+    min-height: 44px;
+  }
+  .tabs .filter-chip {
+    padding-inline: 16px;
+  }
+  .row {
+    padding-block: var(--spacing-lg);
   }
 }