        /* ======================================================================
           1. VARIABLES CSS — TEMA CLARO (valores por defecto)
           ====================================================================== */
        :root {
            /* Fondos */
            --bg-body: #f6f7fa;
            --bg-surface: #ffffff;
            --bg-surface-hover: #f1f2f6;
            --bg-surface-active: #eef0ff;

            /* Bordes */
            --border-color: rgba(15, 23, 42, 0.08);
            --border-color-strong: rgba(15, 23, 42, 0.14);

            /* Texto */
            --text-primary: #111827;
            --text-secondary: #667085;
            --text-tertiary: #98a2b3;
            --text-on-accent: #ffffff;

            /* Acento (degradado de marca) */
            --accent-1: #4f46e5;
            --accent-2: #7c3aed;
            --accent-gradient: linear-gradient(135deg, var(--accent-1) 0%, var(--accent-2) 100%);
            --accent-soft: rgba(79, 70, 229, 0.10);

            /* Sombras */
            --shadow-xs: 0 1px 2px rgba(16, 24, 40, 0.04);
            --shadow-sm: 0 1px 3px rgba(16, 24, 40, 0.06), 0 1px 2px rgba(16, 24, 40, 0.04);
            --shadow-md: 0 6px 16px rgba(16, 24, 40, 0.08);
            --shadow-lg: 0 16px 40px rgba(16, 24, 40, 0.14);

            /* Radios */
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;

            /* Layout */
            --navbar-height: 58px;
            --sidebar-width: 272px;

            /* Movimiento */
            --transition-base: 0.25s cubic-bezier(0.4, 0, 0.2, 1);

            /* Tipografía */
            --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
        }

        /* ======================================================================
           2. VARIABLES CSS — TEMA OSCURO
           Se activa automáticamente cuando <html data-bs-theme="dark">
           ====================================================================== */
        [data-bs-theme="dark"] {
            --bg-body: #0d0f14;
            --bg-surface: #15171f;
            --bg-surface-hover: #1d2029;
            --bg-surface-active: #20223a;

            --border-color: rgba(255, 255, 255, 0.08);
            --border-color-strong: rgba(255, 255, 255, 0.14);

            --text-primary: #f0f1f5;
            --text-secondary: #9aa1b1;
            --text-tertiary: #6b7280;

            --accent-1: #6366f1;
            --accent-2: #a78bfa;
            --accent-soft: rgba(99, 102, 241, 0.16);

            --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.3);
            --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.3);
            --shadow-md: 0 6px 16px rgba(0, 0, 0, 0.45);
            --shadow-lg: 0 20px 48px rgba(0, 0, 0, 0.55);
        }

        /* ======================================================================
           3. RESET / BASE
           ====================================================================== */
        * {
            box-sizing: border-box;
        }

        html,
        body {
            margin: 0;
            padding: 0;
        }

        body {
            font-family: var(--font-sans);
            background-color: var(--bg-body);
            color: var(--text-primary);
            -webkit-font-smoothing: antialiased;
            transition: background-color var(--transition-base), color var(--transition-base);
        }

        /* Evita el scroll del fondo cuando el sidebar está abierto en móvil */
        body.sidebar-open {
            overflow: hidden;
        }

        a {
            text-decoration: none;
            color: inherit;
        }

        button {
            font-family: inherit;
        }

        /* Foco visible accesible, sin el contorno azul por defecto del navegador */
        a:focus-visible,
        button:focus-visible,
        input:focus-visible {
            outline: 2px solid var(--accent-1);
            outline-offset: 2px;
            border-radius: var(--radius-sm);
        }

        /* Scrollbar discreto (Webkit) */
        ::-webkit-scrollbar {
            width: 8px;
            height: 8px;
        }

        ::-webkit-scrollbar-thumb {
            background-color: var(--border-color-strong);
            border-radius: 999px;
        }

        ::-webkit-scrollbar-track {
            background: transparent;
        }

        /* ======================================================================
           4. NAVBAR SUPERIOR
           ====================================================================== */
        .app-navbar {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            height: var(--navbar-height);
            background-color: var(--bg-surface);
            border-bottom: 1px solid var(--border-color);
            box-shadow: var(--shadow-xs);
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 0 1.25rem;
            z-index: 1000;
            transition: background-color var(--transition-base), border-color var(--transition-base);
        }

        .navbar-left {
            display: flex;
            align-items: center;
            gap: 0.85rem;
            min-width: 0;
            /* permite truncar el título en pantallas pequeñas */
        }

        /* Botón hamburguesa */
        .btn-hamburger {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 38px;
            height: 38px;
            flex-shrink: 0;
            background-color: transparent;
            border: none;
            border-radius: var(--radius-sm);
            color: var(--text-secondary);
            cursor: pointer;
            transition: background-color var(--transition-base), color var(--transition-base), transform 0.15s ease;
        }

        .btn-hamburger i {
            font-size: 1.2rem;
            line-height: 1;
        }

        .btn-hamburger:hover {
            background-color: var(--bg-surface-hover);
            color: var(--text-primary);
        }

        .btn-hamburger:active {
            transform: scale(0.94);
        }

        /* Título dinámico de la página (cambia según la vista actual) */
        .page-title {
            font-size: 18px;
            font-weight: 600;
            color: var(--text-primary);
            margin: 0;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .navbar-right {
            display: flex;
            align-items: center;
            gap: 0.4rem;
            flex-shrink: 0;
        }

        /* Ancla de posicionamiento para cada botón con menú desplegable
           del lado derecho (accesos rápidos y usuario) */
        .navbar-action-group {
            position: relative;
        }

        /* Botón de "Accesos rápidos": mismo tamaño y comportamiento visual
           que el botón hamburguesa, ubicado antes del avatar */
        .btn-quick-access {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 38px;
            height: 38px;
            background-color: transparent;
            border: none;
            border-radius: var(--radius-sm);
            color: var(--text-secondary);
            cursor: pointer;
            transition: background-color var(--transition-base), color var(--transition-base);
        }

        .btn-quick-access i {
            font-size: 1.15rem;
            line-height: 1;
        }

        .btn-quick-access:hover {
            background-color: var(--bg-surface-hover);
            color: var(--text-primary);
        }

        /* Resalta el botón mientras su menú está abierto */
        .btn-quick-access[aria-expanded="true"] {
            background-color: var(--bg-surface-active);
            color: var(--accent-1);
        }

        /* Menú desplegable de accesos rápidos */
        .quick-access-dropdown {
            position: absolute;
            top: calc(100% + 10px);
            right: 0;
            width: 220px;
            background-color: var(--bg-surface);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            box-shadow: var(--shadow-lg);
            padding: 0.5rem;
            opacity: 0;
            transform: translateY(-8px) scale(0.98);
            pointer-events: none;
            transition: opacity var(--transition-base), transform var(--transition-base);
            z-index: 1001;
        }

        .quick-access-dropdown.show {
            opacity: 1;
            transform: translateY(0) scale(1);
            pointer-events: auto;
        }

        .quick-access-item {
            display: flex;
            align-items: center;
            gap: 0.65rem;
            padding: 0.55rem 0.75rem;
            margin-bottom: 0.1rem;
            border-radius: var(--radius-sm);
            font-size: 14px;
            font-weight: 500;
            color: var(--text-secondary);
            text-decoration: none;
            transition: background-color var(--transition-base), color var(--transition-base);
        }

        .quick-access-item:last-child {
            margin-bottom: 0;
        }

        .quick-access-item:hover {
            background-color: var(--bg-surface-hover);
            color: var(--text-primary);
        }

        .quick-access-item i {
            font-size: 1.05rem;
            width: 18px;
            text-align: center;
            flex-shrink: 0;
            color: var(--text-tertiary);
            transition: color var(--transition-base);
        }

        .quick-access-item:hover i {
            color: var(--accent-1);
        }

        /* Avatar circular con inicial del usuario */
        .user-avatar {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 38px;
            height: 38px;
            border-radius: 50%;
            background: var(--accent-gradient);
            color: var(--text-on-accent);
            font-weight: 600;
            font-size: 15px;
            border: none;
            cursor: pointer;
            box-shadow: var(--shadow-sm);
            transition: transform var(--transition-base), box-shadow var(--transition-base);
        }

        .user-avatar:hover {
            transform: translateY(-1px);
            box-shadow: var(--shadow-md);
        }

        .user-avatar:active {
            transform: translateY(0);
        }

        /* Menú desplegable del usuario */
        .user-dropdown-menu {
            position: absolute;
            top: calc(100% + 10px);
            right: 0;
            width: 240px;
            background-color: var(--bg-surface);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            box-shadow: var(--shadow-lg);
            padding: 0.5rem;
            opacity: 0;
            transform: translateY(-8px) scale(0.98);
            pointer-events: none;
            transition: opacity var(--transition-base), transform var(--transition-base);
            z-index: 1001;
        }

        .user-dropdown-menu.show {
            opacity: 1;
            transform: translateY(0) scale(1);
            pointer-events: auto;
        }

        .user-dropdown-header {
            padding: 0.65rem 0.75rem 0.5rem;
        }

        .user-dropdown-name {
            font-size: 14px;
            font-weight: 600;
            color: var(--text-primary);
        }

        .user-dropdown-email {
            font-size: 12.5px;
            color: var(--text-tertiary);
        }

        .user-dropdown-divider {
            height: 1px;
            background-color: var(--border-color);
            margin: 0.4rem 0;
        }

        .user-dropdown-item {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 0.6rem;
            width: 100%;
            padding: 0.55rem 0.75rem;
            border-radius: var(--radius-sm);
            font-size: 14px;
            font-weight: 500;
            color: var(--text-secondary);
            background: none;
            border: none;
            cursor: pointer;
            transition: background-color var(--transition-base), color var(--transition-base);
        }

        .user-dropdown-item:hover {
            background-color: var(--bg-surface-hover);
            color: var(--text-primary);
        }

        .user-dropdown-item .item-label {
            display: flex;
            align-items: center;
            gap: 0.55rem;
        }

        .user-dropdown-item i {
            font-size: 1rem;
            color: var(--text-tertiary);
        }

        .user-dropdown-item.danger:hover {
            background-color: rgba(220, 38, 38, 0.08);
            color: #dc2626;
        }

        .user-dropdown-item.danger:hover i {
            color: #dc2626;
        }

        /* Switch de tema (claro / oscuro) dentro del dropdown */
        .theme-switch {
            width: 38px;
            height: 22px;
            margin: 0;
            cursor: pointer;
            background-color: var(--border-color-strong);
            border-color: transparent;
        }

        .theme-switch:checked {
            background-color: var(--accent-1);
            border-color: var(--accent-1);
        }

        .theme-switch:focus {
            box-shadow: none;
        }

        /* ======================================================================
           5. OVERLAY (fondo oscuro al abrir el sidebar)
           ====================================================================== */
        .sidebar-overlay {
            position: fixed;
            inset: 0;
            background-color: rgba(10, 10, 15, 0);
            pointer-events: none;
            transition: background-color var(--transition-base);
            z-index: 1010;
        }

        .sidebar-overlay.show {
            background-color: rgba(10, 10, 15, 0.45);
            pointer-events: auto;
        }

        /* ======================================================================
           6. SIDEBAR LATERAL
           ====================================================================== */
        .app-sidebar {
            position: fixed;
            top: 0;
            left: calc(var(--sidebar-width) * -1);
            width: var(--sidebar-width);
            max-width: 86vw;
            height: 100vh;
            background-color: var(--bg-surface);
            border-right: 1px solid var(--border-color);
            box-shadow: var(--shadow-lg);
            display: flex;
            flex-direction: column;
            z-index: 1020;
            transition: left var(--transition-base);
        }

        .app-sidebar.show {
            left: 0;
        }

        /* Cabecera del sidebar: marca / logo */
        .sidebar-header {
            display: flex;
            align-items: center;
            gap: 0.65rem;
            height: var(--navbar-height);
            padding: 0 1.25rem;
            border-bottom: 1px solid var(--border-color);
            flex-shrink: 0;
        }

        .sidebar-logo-mark {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 32px;
            height: 32px;
            border-radius: var(--radius-sm);
            background: var(--accent-gradient);
            color: #fff;
            font-weight: 700;
            font-size: 15px;
            flex-shrink: 0;
        }

        .sidebar-brand-name {
            font-weight: 700;
            font-size: 15px;
            color: var(--text-primary);
            white-space: nowrap;
        }

        /* Navegación */
        .sidebar-nav {
            flex: 1;
            overflow-y: auto;
            padding: 1rem 0.75rem;
        }

        .nav-group {
            margin-bottom: 1.5rem;
        }

        .nav-group-label {
            font-size: 11px;
            font-weight: 600;
            letter-spacing: 0.06em;
            text-transform: uppercase;
            color: var(--text-tertiary);
            padding: 0 0.6rem;
            margin-bottom: 0.4rem;
        }

        .nav-link-item {
            display: flex;
            align-items: center;
            gap: 0.7rem;
            padding: 0.55rem 0.65rem;
            margin-bottom: 0.15rem;
            border-radius: var(--radius-sm);
            font-size: 14.5px;
            font-weight: 500;
            color: var(--text-secondary);
            transition: background-color var(--transition-base), color var(--transition-base);
        }

        .nav-link-item i {
            font-size: 1.05rem;
            width: 20px;
            text-align: center;
            flex-shrink: 0;
            color: var(--text-tertiary);
            transition: color var(--transition-base);
        }

        .nav-link-item:hover {
            background-color: var(--bg-surface-hover);
            color: var(--text-primary);
        }

        .nav-link-item:hover i {
            color: var(--text-secondary);
        }

        .nav-link-item.active {
            background-color: var(--bg-surface-active);
            color: var(--accent-1);
            font-weight: 600;
        }

        .nav-link-item.active i {
            color: var(--accent-1);
        }

        /* Pie del sidebar */
        .sidebar-footer {
            padding: 0.85rem 1.25rem;
            border-top: 1px solid var(--border-color);
            font-size: 12px;
            color: var(--text-tertiary);
            flex-shrink: 0;
        }

        /* ======================================================================
           7. CONTENIDO PRINCIPAL
           ====================================================================== */
        .app-main {
            margin-top: var(--navbar-height);
            min-height: calc(100vh - var(--navbar-height));
            padding: 1.75rem 1rem;
            background-color: var(--bg-body);
            transition: background-color var(--transition-base);
        }

        /* Contenedor "tarjeta" reutilizable para futuras pantallas */
        .surface-card {
            background-color: var(--bg-surface);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-lg);
            box-shadow: var(--shadow-sm);
            padding: 1.5rem;
            transition: background-color var(--transition-base), border-color var(--transition-base);
        }

        /* ======================================================================
           8. RESPONSIVE
           ====================================================================== */
        @media (max-width: 576px) {
            .app-navbar {
                padding: 0 0.85rem;
            }

            .page-title {
                font-size: 16px;
            }

            .app-main {
                padding: 1.25rem 1rem;
            }

            .user-dropdown-menu {
                right: -0.5rem;
            }
        }

        /* Respeta la preferencia de "menos movimiento" del sistema */
        @media (prefers-reduced-motion: reduce) {

            *,
            *::before,
            *::after {
                transition-duration: 0.01ms !important;
            }
        }