diff --git a/assets/css/styles.css b/assets/css/styles.css
index 7d9ff7b..4cff53b 100644
--- a/assets/css/styles.css
+++ b/assets/css/styles.css
@@ -163,27 +163,27 @@ body {
 /* ── Etiquetas de categoría ───────────────────────────── */
 .sidebar-menu li.sidebar-section {
     border-bottom: none;
-    padding: 14px 18px 3px;
+    padding: 10px 16px 6px;
     font-size: 0.65rem;
     font-weight: 800;
     text-transform: uppercase;
-    letter-spacing: 0.14em;
-    color: rgba(255, 255, 255, 0.40);
-    pointer-events: none;
+    letter-spacing: 0.12em;
+    color: rgba(255, 255, 255, 0.55);
+    pointer-events: auto;
+    cursor: pointer;
     display: flex;
     align-items: center;
+    justify-content: space-between;
     gap: 5px;
     position: relative;
     z-index: 1;
+    border-radius: 6px;
+    margin: 4px 8px 0;
+    transition: background .15s, color .15s;
 }
-
-.sidebar-menu li.sidebar-section::after {
-    content: '';
-    flex: 1;
-    height: 1px;
-    background: rgba(255, 255, 255, 0.12);
-    margin-left: 4px;
-}
+.sidebar-menu li.sidebar-section:hover { color: rgba(255,255,255,.9); background: rgba(255,255,255,.07); }
+.sidebar-menu li.sidebar-section .sb-cat-label { display:flex; align-items:center; gap:4px; }
+.sidebar-menu li.sidebar-section::after { display: none; }
 
 /* ── Badge dentro de un item ──────────────────────────── */
 .sidebar-menu .nav-link .sidebar-badge {
diff --git a/shared/components/sidebar.php b/shared/components/sidebar.php
index 51631ba..c351603 100644
--- a/shared/components/sidebar.php
+++ b/shared/components/sidebar.php
@@ -107,7 +107,7 @@ $_base = defined('APP_URL') ? rtrim(APP_URL, '/') : '';
             <?= htmlspecialchars($_sidebar_title, ENT_QUOTES, 'UTF-8') ?></h4>
     </div>
 
-    <ul class="sidebar-menu">
+    <ul class="sidebar-menu" id="sb-menu">
 
 <?php
 // ── Renderizado dinámico desde ModuleRegistry ───────────────────────────────
@@ -116,57 +116,82 @@ if (class_exists('ModuleRegistry', false)) {
 
     foreach ($sidebarGroups as $catKey => $catData):
         if (empty($catData['modules'])) continue;
-?>
-        <!-- ══ <?= htmlspecialchars($catData['label'], ENT_QUOTES, 'UTF-8') ?> ══ -->
-        <li class="sidebar-section">
-            <i class="<?= htmlspecialchars($catData['icon'], ENT_QUOTES, 'UTF-8') ?> me-1"></i>
-            <?= htmlspecialchars($catData['label'], ENT_QUOTES, 'UTF-8') ?>
-        </li>
 
+        // Detectar si algún link de esta categoría está activo (para auto-expandir)
+        $_catHasActive = false;
+        foreach ($catData['modules'] as $__mod) {
+            $__links = $__mod['links'] ?? [];
+            if (!empty($__links)) {
+                foreach ($__links as $__lnk) {
+                    if ($_isActive($__lnk['route']) !== '') { $_catHasActive = true; break 2; }
+                }
+            } else {
+                $__route = $__mod['route'] ?? '';
+                if ($__route && $_isActive($__route) !== '') { $_catHasActive = true; break; }
+            }
+        }
+        $catId = 'sb-cat-' . htmlspecialchars($catKey, ENT_QUOTES, 'UTF-8');
+?>
+        <li class="sidebar-section<?= $_catHasActive ? ' has-active' : '' ?>"
+            data-cat="<?= $catId ?>"
+            onclick="sbToggleCat('<?= $catId ?>', this)">
+            <span class="sb-cat-label">
+                <i class="<?= htmlspecialchars($catData['icon'], ENT_QUOTES, 'UTF-8') ?> me-1"></i>
+                <?= htmlspecialchars($catData['label'], ENT_QUOTES, 'UTF-8') ?>
+            </span>
+            <i class="fas fa-chevron-down sb-chevron"></i>
+        </li>
+        <li class="sb-group" id="<?= $catId ?>">
+            <ul>
 <?php   foreach ($catData['modules'] as $slug => $mod):
             $links = $mod['links'] ?? [];
-            // Si el módulo declara links propios, mostrarlos todos
             if (!empty($links)):
                 foreach ($links as $lnk):
                     $href   = $_base . $lnk['route'];
                     $active = $_isActive($lnk['route']);
 ?>
-        <li><a href="<?= htmlspecialchars($href, ENT_QUOTES, 'UTF-8') ?>"
-               class="nav-link<?= $active ?>">
-            <i class="<?= htmlspecialchars($lnk['icon'], ENT_QUOTES, 'UTF-8') ?>"></i>
-            <?= htmlspecialchars($lnk['name'], ENT_QUOTES, 'UTF-8') ?></a></li>
+                <li><a href="<?= htmlspecialchars($href, ENT_QUOTES, 'UTF-8') ?>"
+                       class="nav-link<?= $active ?>">
+                    <i class="<?= htmlspecialchars($lnk['icon'], ENT_QUOTES, 'UTF-8') ?>"></i>
+                    <?= htmlspecialchars($lnk['name'], ENT_QUOTES, 'UTF-8') ?></a></li>
 <?php       endforeach;
             else:
-            // Solo la ruta principal del módulo
                 $route  = $mod['route'] ?? '';
                 $href   = $route ? $_base . $route : '#';
                 $active = $route ? $_isActive($route) : '';
 ?>
-        <li><a href="<?= htmlspecialchars($href, ENT_QUOTES, 'UTF-8') ?>"
-               class="nav-link<?= $active ?>">
-            <i class="<?= htmlspecialchars($mod['icon'], ENT_QUOTES, 'UTF-8') ?>"></i>
-            <?= htmlspecialchars($mod['name'], ENT_QUOTES, 'UTF-8') ?></a></li>
+                <li><a href="<?= htmlspecialchars($href, ENT_QUOTES, 'UTF-8') ?>"
+                       class="nav-link<?= $active ?>">
+                    <i class="<?= htmlspecialchars($mod['icon'], ENT_QUOTES, 'UTF-8') ?>"></i>
+                    <?= htmlspecialchars($mod['name'], ENT_QUOTES, 'UTF-8') ?></a></li>
 <?php       endif;
-        endforeach;
-    endforeach;
+        endforeach; ?>
+            </ul>
+        </li>
+
+<?php endforeach;
 
 } else {
-    // ── Fallback estático (cuando ModuleRegistry no está disponible) ──────────
-    // Solo muestra los módulos básicos de laboratorio sin lógica dinámica.
+    // Fallback estático
 ?>
-        <li class="sidebar-section"><i class="fas fa-house-medical me-1"></i> Domicilios</li>
+        <li class="sidebar-section has-active" data-cat="sb-cat-lab" onclick="sbToggleCat('sb-cat-lab',this)">
+            <span class="sb-cat-label"><i class="fas fa-house-medical me-1"></i> Laboratorio</span>
+            <i class="fas fa-chevron-down sb-chevron"></i>
+        </li>
+        <li class="sb-group" id="sb-cat-lab"><ul>
         <?php if (function_exists('hasModule') && hasModule('lab_dashboard')): ?>
-        <li><a href="lab_dashboard.php" class="nav-link"><i class="fas fa-tachometer-alt"></i> Dashboard</a></li>
+            <li><a href="lab_dashboard.php" class="nav-link"><i class="fas fa-tachometer-alt"></i> Dashboard</a></li>
         <?php endif; ?>
         <?php if (function_exists('hasModule') && hasModule('lab_domicilios')): ?>
-        <li><a href="lab_domicilios.php" class="nav-link"><i class="fas fa-house-medical"></i> Domicilios</a></li>
+            <li><a href="lab_domicilios.php" class="nav-link"><i class="fas fa-house-medical"></i> Domicilios</a></li>
         <?php endif; ?>
         <?php if (function_exists('hasModule') && hasModule('lab_pacientes')): ?>
-        <li><a href="lab_pacientes.php" class="nav-link"><i class="fas fa-users"></i> Pacientes</a></li>
+            <li><a href="lab_pacientes.php" class="nav-link"><i class="fas fa-users"></i> Pacientes</a></li>
         <?php endif; ?>
+        </ul></li>
 <?php } ?>
 
-        <!-- ══ Pie del sidebar ══════════════════════════════════ -->
+        <!-- Pie -->
         <li class="sidebar-divider"></li>
         <li><a href="<?= $_base ?>/logout.php" class="nav-link logout-link"
                onclick="return confirm('¿Cerrar sesión?')">
@@ -184,3 +209,99 @@ if (class_exists('ModuleRegistry', false)) {
     </div>
 
 </nav>
+
+<style>
+/* ── Acordeón de categorías ─────────────────────────── */
+.sidebar-section {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    cursor: pointer;
+    user-select: none;
+    padding: 8px 16px 6px;
+    margin-top: 6px;
+    border-radius: 8px 8px 0 0;
+    transition: background .15s;
+}
+.sidebar-section:hover { background: rgba(255,255,255,.08); }
+.sidebar-section .sb-cat-label { display:flex; align-items:center; gap:4px; }
+.sb-chevron {
+    font-size: .65rem;
+    opacity: .7;
+    transition: transform .25s ease;
+    flex-shrink: 0;
+}
+.sidebar-section.collapsed .sb-chevron { transform: rotate(-90deg); }
+
+/* Grupo colapsable */
+.sb-group { overflow: hidden; transition: max-height .28s ease, opacity .2s ease; }
+.sb-group > ul { list-style: none; padding: 0 0 4px; margin: 0; }
+.sb-group.collapsed { max-height: 0 !important; opacity: 0; pointer-events: none; }
+</style>
+
+<script>
+(function () {
+    var STORE_KEY = 'sb_collapsed_cats';
+
+    function getCollapsed() {
+        try { return JSON.parse(localStorage.getItem(STORE_KEY) || '[]'); } catch(_) { return []; }
+    }
+    function setCollapsed(arr) {
+        try { localStorage.setItem(STORE_KEY, JSON.stringify(arr)); } catch(_) {}
+    }
+
+    function applyState(groupEl, sectionEl, collapsed, animate) {
+        if (collapsed) {
+            if (!animate) { groupEl.style.maxHeight = '0'; groupEl.style.opacity = '0'; }
+            groupEl.classList.add('collapsed');
+            sectionEl.classList.add('collapsed');
+        } else {
+            groupEl.classList.remove('collapsed');
+            sectionEl.classList.remove('collapsed');
+            groupEl.style.maxHeight = groupEl.scrollHeight + 'px';
+            groupEl.style.opacity   = '1';
+        }
+    }
+
+    window.sbToggleCat = function(catId, sectionEl) {
+        var group = document.getElementById(catId);
+        if (!group) return;
+        var isCollapsed = group.classList.contains('collapsed');
+        var arr = getCollapsed();
+        if (isCollapsed) {
+            arr = arr.filter(function(id){ return id !== catId; });
+            applyState(group, sectionEl, false, true);
+        } else {
+            if (arr.indexOf(catId) === -1) arr.push(catId);
+            group.style.maxHeight = group.scrollHeight + 'px';
+            group.style.opacity   = '1';
+            requestAnimationFrame(function(){
+                group.classList.add('collapsed');
+                sectionEl.classList.add('collapsed');
+                group.style.maxHeight = '0';
+                group.style.opacity   = '0';
+            });
+        }
+        setCollapsed(arr);
+    };
+
+    // Inicializar al cargar
+    document.addEventListener('DOMContentLoaded', function () {
+        var collapsed = getCollapsed();
+        document.querySelectorAll('.sb-group').forEach(function(group) {
+            var catId    = group.id;
+            var section  = document.querySelector('[data-cat="' + catId + '"]');
+            if (!section) return;
+
+            var hasActive  = !!group.querySelector('.nav-link.active');
+            var isCollapsed = !hasActive && collapsed.indexOf(catId) !== -1;
+
+            // Medir altura real antes de colapsar
+            group.style.maxHeight = group.scrollHeight + 'px';
+            group.style.opacity   = '1';
+
+            applyState(group, section, isCollapsed, false);
+        });
+    });
+})();
+</script>