diff --git a/assets/main.css b/assets/main.css
index 968674c..1ed9d8a 100644
--- a/assets/main.css
+++ b/assets/main.css
@@ -57,6 +57,16 @@ h6 {
     min-height: 100vh;
 }
 
+/* ===== Mobile Header ===== */
+.mobile-header {
+    display: none;
+}
+
+/* ===== Sidebar Backdrop ===== */
+.sidebar-backdrop {
+    display: none;
+}
+
 /* ===== Sidebar ===== */
 .sidebar {
     width: 260px;
@@ -2940,7 +2950,7 @@ h6 {
     color: var(--text-primary);
 }
 
-/* ===== Responsive: Dashboard Pages ===== */
+/* ===== Responsive: Tablet (max-width: 1024px) ===== */
 @media (max-width: 1024px) {
 
     .news-grid,
@@ -2988,10 +2998,97 @@ h6 {
     .news-grid--compact {
         grid-template-columns: repeat(2, 1fr);
     }
+
+    .main-content {
+        padding: 32px 24px;
+    }
+
+    .chat-page {
+        margin: -32px -24px;
+        height: calc(100vh - 64px);
+    }
 }
 
+/* ===== Responsive: Mobile (max-width: 768px) ===== */
 @media (max-width: 768px) {
 
+    /* -- Mobile header bar with hamburger -- */
+    .mobile-header {
+        display: flex;
+        align-items: center;
+        gap: 12px;
+        position: fixed;
+        top: 0;
+        left: 0;
+        right: 0;
+        z-index: 90;
+        height: 56px;
+        padding: 0 16px;
+        background-color: var(--bg-sidebar);
+        border-bottom: 1px solid var(--border-primary);
+    }
+
+    .mobile-menu-btn {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        width: 40px;
+        height: 40px;
+        border: none;
+        border-radius: 8px;
+        background: transparent;
+        color: var(--text-primary);
+        cursor: pointer;
+        transition: background-color 0.15s ease;
+    }
+
+    .mobile-menu-btn:hover {
+        background-color: var(--bg-surface);
+    }
+
+    .mobile-header-title {
+        font-family: 'Space Grotesk', sans-serif;
+        font-size: 18px;
+        font-weight: 700;
+        color: var(--text-heading);
+    }
+
+    /* -- Sidebar: hidden off-screen, slides in as overlay -- */
+    .app-shell {
+        flex-direction: column;
+    }
+
+    .sidebar {
+        position: fixed;
+        top: 0;
+        left: 0;
+        bottom: 0;
+        z-index: 200;
+        transform: translateX(-100%);
+        transition: transform 0.25s ease;
+        width: 280px;
+        min-width: 280px;
+    }
+
+    .sidebar--open {
+        transform: translateX(0);
+    }
+
+    .sidebar-backdrop {
+        display: block;
+        position: fixed;
+        inset: 0;
+        z-index: 199;
+        background-color: rgba(0, 0, 0, 0.5);
+    }
+
+    /* -- Main content: add top padding for mobile header -- */
+    .main-content {
+        padding: 72px 16px 24px;
+        min-height: calc(100vh - 56px);
+    }
+
+    /* -- Dashboard grids -- */
     .news-grid,
     .tools-grid,
     .pricing-grid {
@@ -3002,9 +3099,16 @@ h6 {
         grid-template-columns: 1fr;
     }
 
+    .dashboard-grid {
+        grid-template-columns: 1fr;
+    }
+
+    /* -- Chat page -- */
     .chat-page {
         flex-direction: column;
         height: auto;
+        min-height: calc(100vh - 56px);
+        margin: -72px -16px -24px;
     }
 
     .chat-sidebar-panel {
@@ -3015,11 +3119,34 @@ h6 {
         border-bottom: 1px solid var(--border-primary);
     }
 
+    .chat-messages,
+    .chat-message-list {
+        padding: 16px;
+    }
+
+    .chat-input-bar {
+        padding: 12px 16px;
+    }
+
+    .chat-model-bar {
+        padding: 8px 16px;
+    }
+
+    .chat-bubble {
+        max-width: 90%;
+    }
+
+    /* -- Page header -- */
     .page-header {
         flex-direction: column;
         gap: 12px;
     }
 
+    .page-title {
+        font-size: 22px;
+    }
+
+    /* -- Stats bars -- */
     .analytics-stats-bar {
         flex-direction: column;
     }
@@ -3028,8 +3155,171 @@ h6 {
         flex-direction: column;
     }
 
+    /* -- Sub navigation (Developer/Org tabs) -- */
+    .sub-nav {
+        overflow-x: auto;
+        -webkit-overflow-scrolling: touch;
+        white-space: nowrap;
+        padding-bottom: 12px;
+    }
+
+    .sub-nav-item {
+        flex-shrink: 0;
+    }
+
+    /* -- Modal -- */
     .modal-content {
         min-width: unset;
         margin: 16px;
+        max-width: calc(100vw - 32px);
+    }
+
+    /* -- Dashboard filters -- */
+    .dashboard-filters {
+        overflow-x: auto;
+        -webkit-overflow-scrolling: touch;
+        flex-wrap: nowrap;
+        padding-bottom: 4px;
+    }
+
+    .filter-tab {
+        flex-shrink: 0;
+    }
+
+    /* -- Providers page -- */
+    .providers-layout {
+        grid-template-columns: 1fr;
+    }
+
+    /* -- Tables: horizontal scroll -- */
+    .knowledge-table-wrapper,
+    .org-table-wrapper {
+        margin: 0 -16px;
+        padding: 0 16px;
+    }
+
+    /* -- Settings -- */
+    .settings-input {
+        max-width: 100%;
+    }
+
+    /* -- Placeholder pages -- */
+    .placeholder-card {
+        padding: 32px 20px;
+    }
+
+    /* -- Article detail -- */
+    .article-detail-title {
+        font-size: 18px;
+    }
+
+    .article-detail-content {
+        padding-right: 32px;
+    }
+
+    /* -- CTA banner -- */
+    .cta-banner {
+        padding: 32px 20px;
+    }
+
+    .cta-title {
+        font-size: 22px;
+    }
+
+    .cta-actions {
+        flex-direction: column;
+        align-items: stretch;
+    }
+
+    /* -- Pricing cards -- */
+    .pricing-card {
+        padding: 24px 20px;
+    }
+}
+
+/* ===== Responsive: Small Phones (max-width: 480px) ===== */
+@media (max-width: 480px) {
+
+    .main-content {
+        padding: 64px 12px 16px;
+    }
+
+    .chat-page {
+        margin: -64px -12px -16px;
+    }
+
+    .hero-title {
+        font-size: 28px;
+    }
+
+    .hero-subtitle {
+        font-size: 15px;
+    }
+
+    .section-title {
+        font-size: 24px;
+    }
+
+    .page-title {
+        font-size: 20px;
+    }
+
+    .overview-heading {
+        font-size: 22px;
+    }
+
+    .dashboard-card {
+        padding: 16px;
+    }
+
+    .tool-card {
+        padding: 16px;
+    }
+
+    .news-card-body {
+        padding: 14px;
+    }
+
+    .social-proof-stats {
+        gap: 16px;
+    }
+
+    .proof-divider {
+        display: none;
+    }
+
+    .proof-stat-value {
+        font-size: 20px;
+    }
+
+    .sidebar {
+        width: 260px;
+        min-width: 260px;
+    }
+
+    .chat-bubble {
+        max-width: 95%;
+        padding: 10px 14px;
+    }
+
+    .modal-content {
+        padding: 20px;
+    }
+
+    .landing-nav-inner {
+        padding: 12px 16px;
+    }
+
+    .features-section,
+    .how-it-works-section {
+        padding: 48px 16px;
+    }
+
+    .step-card {
+        padding: 24px 16px;
+    }
+
+    .feature-card {
+        padding: 20px 16px;
     }
 }
\ No newline at end of file
diff --git a/assets/tailwind.css b/assets/tailwind.css
index ab4799a..c7c9fdd 100644
--- a/assets/tailwind.css
+++ b/assets/tailwind.css
@@ -356,6 +356,95 @@
       }
     }
   }
+  .dropdown {
+    @layer daisyui.l1.l2.l3 {
+      position: relative;
+      display: inline-block;
+      position-area: var(--anchor-v, bottom) var(--anchor-h, span-right);
+      & > *:not(:has(~ [class*="dropdown-content"])):focus {
+        --tw-outline-style: none;
+        outline-style: none;
+        @media (forced-colors: active) {
+          outline: 2px solid transparent;
+          outline-offset: 2px;
+        }
+      }
+      .dropdown-content {
+        position: absolute;
+      }
+      &.dropdown-close .dropdown-content, &:not(details, .dropdown-open, .dropdown-hover:hover, :focus-within) .dropdown-content, &.dropdown-hover:not(:hover) [tabindex]:first-child:focus:not(:focus-visible) ~ .dropdown-content {
+        display: none;
+        transform-origin: top;
+        opacity: 0%;
+        scale: 95%;
+      }
+      &[popover], .dropdown-content {
+        z-index: 999;
+        @media (prefers-reduced-motion: no-preference) {
+          animation: dropdown 0.2s;
+          transition-property: opacity, scale, display;
+          transition-behavior: allow-discrete;
+          transition-duration: 0.2s;
+          transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
+        }
+      }
+      @starting-style {
+        &[popover], .dropdown-content {
+          scale: 95%;
+          opacity: 0;
+        }
+      }
+      &:not(.dropdown-close) {
+        &.dropdown-open, &:not(.dropdown-hover):focus, &:focus-within {
+          > [tabindex]:first-child {
+            pointer-events: none;
+          }
+          .dropdown-content {
+            opacity: 100%;
+            scale: 100%;
+          }
+        }
+        &.dropdown-hover:hover {
+          .dropdown-content {
+            opacity: 100%;
+            scale: 100%;
+          }
+        }
+      }
+      &:is(details) {
+        summary {
+          &::-webkit-details-marker {
+            display: none;
+          }
+        }
+      }
+      &:where([popover]) {
+        background: #0000;
+      }
+      &[popover] {
+        position: fixed;
+        color: inherit;
+        @supports not (position-area: bottom) {
+          margin: auto;
+          &.dropdown-close, &.dropdown-open:not(:popover-open) {
+            display: none;
+            transform-origin: top;
+            opacity: 0%;
+            scale: 95%;
+          }
+          &::backdrop {
+            background-color: color-mix(in oklab, #000 30%, #0000);
+          }
+        }
+        &.dropdown-close, &:not(.dropdown-open, :popover-open) {
+          display: none;
+          transform-origin: top;
+          opacity: 0%;
+          scale: 95%;
+        }
+      }
+    }
+  }
   .btn {
     :where(&) {
       @layer daisyui.l1.l2.l3 {
diff --git a/src/components/app_shell.rs b/src/components/app_shell.rs
index 8f47801..c129558 100644
--- a/src/components/app_shell.rs
+++ b/src/components/app_shell.rs
@@ -1,4 +1,6 @@
 use dioxus::prelude::*;
+use dioxus_free_icons::icons::bs_icons::{BsList, BsX};
+use dioxus_free_icons::Icon;
 
 use crate::components::sidebar::Sidebar;
 use crate::i18n::{t, tw, Locale};
@@ -14,6 +16,7 @@ use crate::Route;
 #[component]
 pub fn AppShell() -> Element {
     let locale = use_context::<Signal<Locale>>();
+    let mut mobile_menu_open = use_signal(|| false);
 
     // use_resource memoises the async call and avoids infinite re-render
     // loops that use_effect + spawn + signal writes can cause.
@@ -26,12 +29,44 @@ pub fn AppShell() -> Element {
 
     match auth_snapshot {
         Some(Ok(info)) if info.authenticated => {
+            let menu_open = *mobile_menu_open.read();
+            let sidebar_cls = if menu_open {
+                "sidebar sidebar--open"
+            } else {
+                "sidebar"
+            };
+
             rsx! {
                 div { class: "app-shell",
+                    // Mobile top bar (visible only on small screens via CSS)
+                    header { class: "mobile-header",
+                        button {
+                            class: "mobile-menu-btn",
+                            onclick: move |_| {
+                                let current = *mobile_menu_open.read();
+                                mobile_menu_open.set(!current);
+                            },
+                            if menu_open {
+                                Icon { icon: BsX, width: 24, height: 24 }
+                            } else {
+                                Icon { icon: BsList, width: 24, height: 24 }
+                            }
+                        }
+                        span { class: "mobile-header-title", "CERTifAI" }
+                    }
+                    // Backdrop overlay when sidebar is open on mobile
+                    if menu_open {
+                        div {
+                            class: "sidebar-backdrop",
+                            onclick: move |_| mobile_menu_open.set(false),
+                        }
+                    }
                     Sidebar {
                         email: info.email,
                         name: info.name,
                         avatar_url: info.avatar_url,
+                        class: sidebar_cls,
+                        on_nav: move |_| mobile_menu_open.set(false),
                     }
                     main { class: "main-content", Outlet::<Route> {} }
                 }
diff --git a/src/components/sidebar.rs b/src/components/sidebar.rs
index fcfc324..0cc8ac3 100644
--- a/src/components/sidebar.rs
+++ b/src/components/sidebar.rs
@@ -27,8 +27,19 @@ struct NavItem {
 /// * `name` - User display name (shown in header if non-empty).
 /// * `email` - Email address displayed beneath the avatar placeholder.
 /// * `avatar_url` - URL for the avatar image (unused placeholder for now).
+/// * `class` - CSS class override (e.g. to add `sidebar--open` on mobile).
+/// * `on_nav` - Callback fired when a nav link is clicked (used to close
+///   the mobile menu).
 #[component]
-pub fn Sidebar(name: String, email: String, avatar_url: String) -> Element {
+pub fn Sidebar(
+    name: String,
+    email: String,
+    avatar_url: String,
+    #[props(default = "sidebar".to_string())]
+    class: String,
+    #[props(default)]
+    on_nav: EventHandler<()>,
+) -> Element {
     let locale = use_context::<Signal<Locale>>();
     let locale_val = *locale.read();
 
@@ -82,7 +93,7 @@ pub fn Sidebar(name: String, email: String, avatar_url: String) -> Element {
     let logout_label = t(locale_val, "common.logout");
 
     rsx! {
-        aside { class: "sidebar",
+        aside { class: "{class}",
             div { class: "sidebar-top-row",
                 SidebarHeader { name, email: email.clone(), avatar_url }
                 LocalePicker {}
@@ -104,7 +115,10 @@ pub fn Sidebar(name: String, email: String, avatar_url: String) -> Element {
                         };
                         let cls = if is_active { "sidebar-link active" } else { "sidebar-link" };
                         rsx! {
-                            Link { to: item.route, class: cls,
+                            Link {
+                                to: item.route,
+                                class: cls,
+                                onclick: move |_| on_nav.call(()),
                                 {item.icon}
                                 span { "{item.label}" }
                             }