diff --git a/index.html b/index.html
index 7daa68a..02b0605 100644
--- a/index.html
+++ b/index.html
@@ -21,8 +21,9 @@
     <div class="ambient ambient-two"></div>
 
     <main class="shell">
-      <section class="hero" aria-labelledby="page-title">
-        <div class="hero-content">
+      <div class="app-layout">
+        <aside class="side-panel" aria-label="Навигация по экосистеме">
+          <div class="hero-content">
           <button
             class="settings-button"
             type="button"
@@ -69,8 +70,9 @@
             </div>
           </section>
 
-        </div>
-      </section>
+          <nav class="nav-tree" aria-label="Дерево навигации" data-nav-tree></nav>
+          </div>
+        </aside>
 
       <div class="settings-overlay" data-settings-overlay></div>
       <div class="control-panel" aria-label="Настройки панели" data-settings-panel>
@@ -147,15 +149,16 @@
         </div>
       </div>
 
-      <section class="catalog cards-view" aria-live="polite" data-catalog-root></section>
+        <section class="catalog cards-view" aria-live="polite" data-catalog-root></section>
 
-      <template id="empty-template">
-        <div class="empty-state">
-          <img src="assets/search.svg" alt="" />
-          <h2>Ничего не найдено</h2>
-          <p>Попробуй изменить запрос или искать по названию системы, тегу или роли.</p>
-        </div>
-      </template>
+        <template id="empty-template">
+          <div class="empty-state">
+            <img src="assets/search.svg" alt="" />
+            <h2>Ничего не найдено</h2>
+            <p>Попробуй изменить запрос или искать по названию системы, тегу или роли.</p>
+          </div>
+        </template>
+      </div>
     </main>
 
     <script src="script.js"></script>
diff --git a/script.js b/script.js
index 5d0141a..1b9c076 100644
--- a/script.js
+++ b/script.js
@@ -142,6 +142,7 @@ const availableViews = ["cards", "list", "compact-cards", "compact-list"];
 
 const preferences = { ...defaultPreferences, ...readPreferences() };
 const catalog = document.querySelector("[data-catalog-root]");
+const navTree = document.querySelector("[data-nav-tree]");
 const searchInput = document.querySelector("[data-search-input]");
 const settingsToggle = document.querySelector("[data-settings-toggle]");
 const settingsPanel = document.querySelector("[data-settings-panel]");
@@ -158,11 +159,24 @@ document.querySelector("[data-total-sections]").textContent = totals.sections;
 document.querySelector("[data-total-groups]").textContent = totals.groups;
 document.querySelector("[data-total-items]").textContent = totals.items;
 
+renderNavigationTree();
 applyPreferences(preferences);
 renderCatalog();
 
 searchInput.addEventListener("input", renderCatalog);
 
+navTree.addEventListener("click", (event) => {
+  const button = event.target.closest("[data-focus-target]");
+
+  if (!button) {
+    return;
+  }
+
+  event.preventDefault();
+  event.stopPropagation();
+  focusCatalogTarget(button.dataset.focusTarget);
+});
+
 settingsToggle.addEventListener("click", () => {
   const isOpen = settingsPanel.classList.toggle("is-open");
   settingsOverlay.classList.toggle("is-open", isOpen);
@@ -268,6 +282,8 @@ function renderCatalog() {
 function createSectionElement(section) {
   const sectionElement = document.createElement("details");
   sectionElement.className = "catalog-section";
+  sectionElement.id = getSectionId(section);
+  sectionElement.tabIndex = -1;
   sectionElement.open = true;
   sectionElement.innerHTML = `
     <summary class="section-head">
@@ -289,6 +305,8 @@ function createSectionElement(section) {
 function createGroupElement(group, items) {
   const groupElement = document.createElement("details");
   groupElement.className = "catalog-group";
+  groupElement.id = getGroupId(group);
+  groupElement.tabIndex = -1;
   groupElement.open = true;
 
   const cards = items.map(createCardElement);
@@ -319,6 +337,7 @@ function createCardElement(item) {
   const link = document.createElement("a");
   link.className = "nav-card";
   link.href = item.url;
+  link.id = getItemId(item);
   link.dataset.type = item.type;
 
   if (item.url === "#") {
@@ -365,6 +384,75 @@ function matchesQuery(item, group, section, query) {
   return haystack.includes(query);
 }
 
+function renderNavigationTree() {
+  const fragment = document.createDocumentFragment();
+
+  ecosystemSections.forEach((section) => {
+    const sectionNode = document.createElement("details");
+    sectionNode.className = "tree-section";
+    sectionNode.open = true;
+
+    const sectionSummary = document.createElement("summary");
+    sectionSummary.innerHTML = `
+      <span>${section.title}</span>
+      <button type="button" data-focus-target="${getSectionId(section)}">Фокус</button>
+    `;
+    sectionNode.append(sectionSummary);
+
+    section.groups.forEach((group) => {
+      const groupNode = document.createElement("details");
+      groupNode.className = "tree-group";
+      groupNode.open = true;
+
+      const groupSummary = document.createElement("summary");
+      groupSummary.innerHTML = `
+        <span>${group.title}</span>
+        <button type="button" data-focus-target="${getGroupId(group)}">Фокус</button>
+      `;
+      groupNode.append(groupSummary);
+
+      const itemList = document.createElement("div");
+      itemList.className = "tree-items";
+
+      group.items.forEach((item) => {
+        const itemButton = document.createElement("button");
+        itemButton.type = "button";
+        itemButton.dataset.focusTarget = getItemId(item);
+        itemButton.innerHTML = `<span>${item.title}</span><small>${serviceMeta[item.type]?.label || item.type}</small>`;
+        itemList.append(itemButton);
+      });
+
+      groupNode.append(itemList);
+      sectionNode.append(groupNode);
+    });
+
+    fragment.append(sectionNode);
+  });
+
+  navTree.replaceChildren(fragment);
+}
+
+function focusCatalogTarget(targetId) {
+  let target = document.getElementById(targetId);
+
+  if (!target) {
+    searchInput.value = "";
+    renderCatalog();
+    target = document.getElementById(targetId);
+  }
+
+  if (!target) {
+    return;
+  }
+
+  target.closest(".catalog-section")?.setAttribute("open", "");
+  target.closest(".catalog-group")?.setAttribute("open", "");
+  target.scrollIntoView({ behavior: "smooth", block: "center" });
+  target.focus({ preventScroll: true });
+  target.classList.add("is-focused");
+  window.setTimeout(() => target.classList.remove("is-focused"), 1200);
+}
+
 function attachCardInteractions() {
   document.querySelectorAll(".nav-card").forEach((card) => {
     let leaveTimer;
@@ -442,6 +530,18 @@ function normalize(value) {
   return value.toLowerCase().replaceAll("ё", "е").trim();
 }
 
+function getSectionId(section) {
+  return `section-${section.id}`;
+}
+
+function getGroupId(group) {
+  return `group-${group.id}`;
+}
+
+function getItemId(item) {
+  return `item-${item.number.replaceAll(".", "-")}`;
+}
+
 function clamp(value, min, max) {
   return Math.min(Math.max(value, min), max);
 }
diff --git a/styles.css b/styles.css
index 9680a20..0024123 100644
--- a/styles.css
+++ b/styles.css
@@ -107,6 +107,19 @@ a {
   padding: 20px 0;
 }
 
+.app-layout {
+  display: grid;
+  grid-template-columns: minmax(280px, 340px) minmax(0, 1fr);
+  gap: 12px;
+  align-items: start;
+}
+
+.side-panel {
+  position: sticky;
+  top: 20px;
+  min-width: 0;
+}
+
 .hero {
   display: block;
   margin-bottom: 12px;
@@ -123,7 +136,8 @@ a {
 }
 
 .hero-content {
-  min-height: 190px;
+  max-height: calc(100vh - 40px);
+  min-height: 0;
   display: flex;
   flex-direction: column;
   justify-content: center;
@@ -134,6 +148,19 @@ a {
   overflow: visible;
 }
 
+.side-panel .hero-content {
+  justify-content: flex-start;
+  overflow: auto;
+}
+
+.side-panel h1 {
+  font-size: clamp(1.65rem, 2.4vw, 2.45rem);
+}
+
+.side-panel .lead {
+  font-size: 0.9rem;
+}
+
 .hero-content::before {
   content: "";
   position: absolute;
@@ -497,14 +524,124 @@ html:not([data-show-numbers="true"]) .item-number {
   text-transform: uppercase;
 }
 
+.nav-tree {
+  display: grid;
+  gap: 8px;
+  min-height: 0;
+  padding-top: 4px;
+}
+
+.tree-section,
+.tree-group {
+  border: 1px solid var(--border);
+  border-radius: 16px;
+  background: rgba(255, 255, 255, 0.035);
+  overflow: hidden;
+}
+
+.tree-group {
+  margin: 6px 8px 8px;
+  border-radius: 14px;
+}
+
+.tree-section > summary,
+.tree-group > summary {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
+  gap: 8px;
+  align-items: center;
+  list-style: none;
+  cursor: pointer;
+  padding: 9px 10px;
+}
+
+.tree-section > summary::-webkit-details-marker,
+.tree-group > summary::-webkit-details-marker {
+  display: none;
+}
+
+.tree-section summary span,
+.tree-group summary span {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: var(--text);
+  font-size: 0.88rem;
+  font-weight: 850;
+}
+
+.tree-group summary span {
+  font-size: 0.82rem;
+  color: var(--muted);
+}
+
+.tree-section summary button,
+.tree-group summary button,
+.tree-items button {
+  border: 1px solid var(--border);
+  border-radius: 999px;
+  cursor: pointer;
+  color: var(--accent);
+  background: rgba(var(--accent-rgb), 0.1);
+  font: inherit;
+  font-size: 0.72rem;
+  font-weight: 850;
+}
+
+.tree-section summary button,
+.tree-group summary button {
+  padding: 4px 7px;
+}
+
+.tree-items {
+  display: grid;
+  gap: 4px;
+  padding: 0 8px 8px;
+}
+
+.tree-items button {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
+  gap: 8px;
+  align-items: center;
+  width: 100%;
+  padding: 7px 9px;
+  border-radius: 12px;
+  text-align: left;
+  background: transparent;
+}
+
+.tree-items button:hover,
+.tree-section summary button:hover,
+.tree-group summary button:hover {
+  border-color: rgba(var(--accent-rgb), 0.5);
+  background: rgba(var(--accent-rgb), 0.14);
+}
+
+.tree-items span {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: var(--text);
+}
+
+.tree-items small {
+  color: var(--muted);
+  font-weight: 800;
+}
+
 .catalog {
   display: grid;
   gap: 12px;
+  min-width: 0;
 }
 
 .catalog-section {
   border-radius: 24px;
   overflow: hidden;
+  scroll-margin-top: 18px;
 }
 
 .catalog-section,
@@ -605,6 +742,7 @@ html:not([data-show-numbers="true"]) .item-number {
   border-radius: 18px;
   background: rgba(255, 255, 255, 0.035);
   overflow: hidden;
+  scroll-margin-top: 18px;
 }
 
 .group-head {
@@ -662,6 +800,14 @@ html:not([data-show-numbers="true"]) .item-number {
     border-color 220ms ease,
     background 220ms ease,
     box-shadow 220ms ease;
+  scroll-margin-top: 18px;
+}
+
+.catalog-section.is-focused,
+.catalog-group.is-focused,
+.nav-card.is-focused {
+  border-color: rgba(var(--accent-rgb), 0.75);
+  box-shadow: 0 0 0 4px rgba(var(--accent-rgb), 0.16), var(--shadow);
 }
 
 .nav-card::before {
@@ -899,6 +1045,10 @@ html:not([data-show-numbers="true"]) .item-number {
 }
 
 @media (max-width: 1120px) {
+  .app-layout {
+    grid-template-columns: minmax(240px, 300px) minmax(0, 1fr);
+  }
+
   .items-grid {
     grid-template-columns: repeat(2, minmax(0, 1fr));
   }
@@ -914,12 +1064,26 @@ html:not([data-show-numbers="true"]) .item-number {
     padding: 14px 0;
   }
 
+  .app-layout {
+    grid-template-columns: 1fr;
+  }
+
+  .side-panel {
+    position: static;
+  }
+
   .hero-content {
     min-height: auto;
+    max-height: none;
     padding: 16px 14px;
     border-radius: 20px;
   }
 
+  .nav-tree {
+    max-height: 320px;
+    overflow: auto;
+  }
+
   .control-panel,
   .catalog-section,
   .empty-state {