/* ============================================================
   Variables Globales (Diseño Premium)
   ============================================================ */
:root {
    --bg-primary: #080f1e;
    --bg-secondary: #111827;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --accent-primary: #8b5cf6;
    --accent-secondary: #38bdf8;
    --accent-hover: #7c3aed;
    --accent-glow: rgba(139, 92, 246, 0.4);
    --color-info: #38bdf8;
    --color-tip: #34d399;
    --color-warning: #fbbf24;
    --color-analogy: #a78bfa;
    --color-success: #34d399;
    --color-error: #f87171;
    --glass-bg: rgba(15, 23, 42, 0.65);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-border-hover: rgba(139, 92, 246, 0.45);
    --code-bg: #030712;
    --sidebar-bg: rgba(8, 15, 30, 0.85);
    --font-sans: 'Inter', system-ui, sans-serif;
    --font-mono: 'Fira Code', monospace;
    --sidebar-width: 300px;
    --topbar-height: 68px;
    --transition-smooth: cubic-bezier(0.4, 0, 0.2, 1);
    --transition-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* ============================================================
   Reset & Global Scrollbar
   ============================================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.15);
    border-radius: 99px;
    border: 2px solid var(--bg-primary);
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(139, 92, 246, 0.5);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    background-image:
        radial-gradient(ellipse 80% 60% at 10% 0%, rgba(139, 92, 246, 0.18) 0%, transparent 50%),
        radial-gradient(ellipse 60% 50% at 90% 20%, rgba(56, 189, 248, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse 50% 40% at 60% 90%, rgba(52, 211, 153, 0.07) 0%, transparent 50%);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.8;
    overflow-x: hidden;
    font-size: 1rem;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    line-height: 1.25;
    margin-bottom: 1rem;
}

/* ============================================================
   Glassmorphism
   ============================================================ */
.glass-panel {
    background: var(--glass-bg);
    -webkit-backdrop-filter: blur(32px) saturate(200%);
    backdrop-filter: blur(32px) saturate(200%);
    border: 1px solid var(--glass-border);
    box-shadow:
        inset 0 1px 0 rgba(255, 255, 255, 0.06),
        0 20px 60px -10px rgba(0, 0, 0, 0.6),
        0 0 0 0 var(--accent-glow);
    border-radius: 20px;
    position: relative;
    overflow: hidden;
    transition: border-color 0.35s var(--transition-smooth),
        box-shadow 0.35s var(--transition-smooth);
}

.glass-panel::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.05) 0%, transparent 60%);
    pointer-events: none;
    z-index: 0;
}

.glass-panel:hover {
    /* Brillo y sombras masivas DESACTIVADOS completamente para evitar 
       efectos indeseados en contenedores grandes como #contentArea.
       Las interacciones se manejan granularmente! */
    border-color: var(--glass-border-hover);
}

/* ============================================================
   Layout Principal
   ============================================================ */
.app-container {
    display: flex;
    min-height: 100vh;
}

/* ============================================================
   Sidebar
   ============================================================ */
.sidebar {
    width: var(--sidebar-width);
    height: 100vh;
    position: fixed;
    left: 0;
    top: 0;
    display: flex;
    flex-direction: column;
    z-index: 100;
    transition: transform 0.35s var(--transition-smooth);
    border-right: 1px solid rgba(139, 92, 246, 0.15);
    border-radius: 0 20px 20px 0;
    background: var(--sidebar-bg);
    -webkit-backdrop-filter: blur(40px) saturate(180%);
    backdrop-filter: blur(40px) saturate(180%);
}

.sidebar-header {
    padding: 1.5rem 1.5rem 1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    position: relative;
}

.sidebar-header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 1rem;
    right: 1rem;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(139, 92, 246, 0.5), transparent);
}

.sidebar-header h2 {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.75px;
    margin: 0 0 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.sidebar-header span {
    background: linear-gradient(135deg, #a78bfa 0%, #38bdf8 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Barra de progreso en sidebar */
.progress-container {
    margin-top: 0.25rem;
}

.progress-label {
    font-size: 0.78rem;
    color: var(--text-secondary);
    margin-bottom: 0.4rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.progress-label strong {
    color: var(--color-tip);
    font-size: 0.82rem;
}

.progress-bar-track {
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 99px;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-primary), var(--color-tip));
    border-radius: 99px;
    width: 0%;
    transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Buscador */
.search-container {
    padding: 0.75rem 1.25rem;
    border-bottom: 1px solid var(--glass-border);
}

.search-input {
    width: 100%;
    padding: 0.6rem 1rem;
    background: rgba(2, 6, 23, 0.6);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 0.875rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.search-input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(139, 92, 246, 0.25);
}

.search-input::placeholder {
    color: var(--text-secondary);
}

/* Menú de navegación */
.nav-menu {
    list-style: none;
    padding: 0;
    overflow-y: auto;
    flex: 1;
}

.nav-menu::-webkit-scrollbar {
    width: 4px;
}

.nav-menu::-webkit-scrollbar-track {
    background: transparent;
}

.nav-menu::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 99px;
}

.category-group {
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.category-btn {
    width: 100%;
    text-align: left;
    background: transparent;
    color: var(--text-primary);
    border: none;
    padding: 0.875rem 1.5rem;
    font-weight: 700;
    font-size: 0.875rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.2s;
}

.category-btn:hover {
    background: rgba(255, 255, 255, 0.05);
}

.category-icon {
    font-size: 0.75rem;
    transition: transform 0.3s;
    opacity: 0.6;
}

.category-items {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease-out;
    background: rgba(0, 0, 0, 0.2);
    list-style: none;
}

.category-items.open {
    max-height: 600px;
}

.category-btn.open .category-icon {
    transform: rotate(180deg);
}

.nav-item {
    margin: 0;
}

.nav-btn {
    width: 100%;
    text-align: left;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 0.6rem 1rem 0.6rem 2rem;
    border-radius: 0 8px 8px 0;
    margin-right: 0.5rem;
    font-family: inherit;
    font-size: 0.855rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.22s var(--transition-smooth);
    border-left: 2px solid transparent;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
    position: relative;
}

.nav-btn:hover {
    background: rgba(139, 92, 246, 0.07);
    color: var(--text-primary);
    transform: translateX(4px);
    border-left-color: rgba(139, 92, 246, 0.4);
}

.nav-btn.active {
    background: linear-gradient(90deg, rgba(139, 92, 246, 0.18) 0%, rgba(56, 189, 248, 0.06) 100%);
    color: var(--text-primary);
    border-left: 2px solid var(--accent-primary);
    font-weight: 600;
    box-shadow: inset 0 0 20px rgba(139, 92, 246, 0.05);
}

.nav-btn .nav-btn-icons {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    flex-shrink: 0;
}

.completed-check {
    display: none;
    color: var(--color-tip);
    font-size: 0.8rem;
    font-weight: 700;
}

.nav-btn.completed .completed-check {
    display: inline;
}

.diff-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    flex-shrink: 0;
    opacity: 0.7;
}

.diff-dot.beginner {
    background: var(--color-tip);
}

.diff-dot.intermediate {
    background: var(--color-warning);
}

.diff-dot.advanced {
    background: var(--color-error);
}

/* ============================================================
   Área Principal
   ============================================================ */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    min-width: 0;
}

.topbar {
    height: var(--topbar-height);
    display: flex;
    align-items: center;
    padding: 0 1.5rem;
    position: sticky;
    top: 0;
    z-index: 90;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    gap: 1rem;
    background: rgba(8, 15, 30, 0.7);
    -webkit-backdrop-filter: blur(30px);
    backdrop-filter: blur(30px);
}

.menu-btn {
    display: none;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
    flex-shrink: 0;
}

#pageTitle {
    font-size: 1.35rem;
    font-weight: 600;
    margin: 0;
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.topbar-badge {
    font-size: 0.72rem;
    font-weight: 700;
    padding: 0.22rem 0.7rem;
    border-radius: 99px;
    flex-shrink: 0;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.topbar-badge.beginner {
    background: rgba(34, 197, 94, 0.12);
    color: var(--color-tip);
    border: 1px solid rgba(34, 197, 94, 0.3);
}

.topbar-badge.intermediate {
    background: rgba(245, 158, 11, 0.12);
    color: var(--color-warning);
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.topbar-badge.advanced {
    background: rgba(239, 68, 68, 0.12);
    color: var(--color-error);
    border: 1px solid rgba(239, 68, 68, 0.3);
}

.content-area {
    margin: 1rem;
    border-radius: 16px;
    padding: 1.5rem;
    flex: 1;
    box-sizing: border-box;
    align-self: stretch;
}

/* Navegación entre lecciones */
.lesson-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 1rem 2rem 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--glass-border);
    gap: 1rem;
}

.lesson-nav-btn {
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    color: var(--text-secondary);
    padding: 0.75rem 1.1rem;
    border-radius: 12px;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    text-align: left;
    max-width: 46%;
    min-width: 120px;
    overflow: hidden;
}

.lesson-nav-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at center, rgba(139, 92, 246, 0.15) 0%, transparent 60%);
    opacity: 0;
    transition: opacity 0.4s ease;
}

.lesson-nav-btn:hover {
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.15), rgba(59, 130, 246, 0.1));
    border-color: rgba(139, 92, 246, 0.5);
    color: white;
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 10px 20px -5px rgba(139, 92, 246, 0.3);
}

.lesson-nav-btn:hover::before {
    opacity: 1;
}

.lesson-nav-btn.next-btn {
    text-align: right;
}

.lesson-nav-btn.next-btn:hover {
    transform: translateY(-3px) scale(1.02);
}

.nav-label {
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--accent-primary);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.nav-title {
    display: block;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    color: var(--text-primary);
    font-size: 0.85rem;
}

/* ============================================================
   Animaciones
   ============================================================ */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(15px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes successPulse {
    0% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.02);
    }

    100% {
        transform: scale(1);
    }
}

@keyframes shake {

    0%,
    100% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-5px);
    }

    75% {
        transform: translateX(5px);
    }
}

@keyframes latido {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.15);
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes popIn {
    from {
        transform: scale(0.92);
        opacity: 0;
    }

    to {
        transform: scale(1);
        opacity: 1;
    }
}

/* ─── Sistema de Notificaciones Antigravity ─── */
.antigravity-notify {
    position: fixed;
    top: 30px;
    right: -400px;
    width: 320px;
    background: rgba(255, 255, 255, 0.08);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 16px;
    padding: 16px;
    display: flex;
    gap: 15px;
    z-index: 20000;
    transition: all 0.6s cubic-bezier(0.23, 1, 0.32, 1);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.3);
}

.antigravity-notify.show {
    right: 30px;
}

.antigravity-notify.success {
    border-left: 4px solid var(--gl-accent);
}

.notify-icon {
    font-size: 24px;
    display: flex;
    align-items: center;
}

.notify-title {
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--gl-accent);
    margin-bottom: 4px;
}

.notify-text {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.4;
}

/* ─── Animaciones de Éxito ─── */
.success-anim {
    animation: successPulse 0.5s ease;
}

@keyframes successPulse {
    0% {
        transform: scale(0.95);
        opacity: 0;
    }

    50% {
        transform: scale(1.02);
    }

    100% {
        transform: scale(1);
        opacity: 1;
    }
}

/* ============================================================
   Tipografía de contenido
   ============================================================ */
.content-area h2 {
    font-size: 1.95rem;
    color: var(--text-primary);
    margin-top: 1.75rem;
    margin-bottom: 1rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.2;
    background: linear-gradient(135deg, var(--text-primary) 60%, rgba(167, 139, 250, 0.8));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.content-area h2:first-child {
    margin-top: 0;
}

.content-area h3 {
    font-size: 1.3rem;
    color: var(--text-primary);
    margin-top: 2rem;
    margin-bottom: 0.75rem;
    font-weight: 700;
    letter-spacing: -0.01em;
}

.content-area h4 {
    font-size: 1.05rem;
    color: var(--text-primary);
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.content-area p {
    margin-bottom: 1.3rem;
    color: var(--text-secondary);
    font-size: 1.02rem;
    line-height: 1.9;
}

.content-area strong {
    color: var(--text-primary);
    font-weight: 600;
}

.content-area ul,
.content-area ol {
    margin: 0 0 1.3rem 1.25rem;
    color: var(--text-secondary);
    font-size: 1.02rem;
    line-height: 1.9;
}

.content-area li {
    margin-bottom: 0.35rem;
    padding-left: 0.25rem;
}

/* ============================================================
   Bloques de Código
   ============================================================ */
pre {
    background: var(--code-bg);
    border-radius: 12px;
    overflow-x: auto;
    margin: 1.75rem 0;
    border: 1px solid rgba(255, 255, 255, 0.06);
    position: relative;
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.04);
}

pre::before {
    content: '';
    display: block;
    padding: 0.6rem 1rem;
    background: rgba(255, 255, 255, 0.03);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 12px 12px 0 0;
}

pre code {
    display: block;
    padding: 1.25rem 1.5rem;
    color: #d1d9e0;
    font-size: 0.88rem;
    line-height: 1.75;
    text-align: justify;
    hyphens: auto;
}

.copy-btn {
    position: absolute;
    top: 0.4rem;
    right: 0.6rem;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid rgba(255, 255, 255, 0.08);
    color: var(--text-secondary);
    padding: 0.2rem 0.65rem;
    border-radius: 6px;
    font-size: 0.75rem;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: var(--font-sans);
    font-weight: 500;
    letter-spacing: 0.02em;
}

.copy-btn:hover {
    background: rgba(139, 92, 246, 0.2);
    border-color: rgba(139, 92, 246, 0.4);
    color: var(--text-primary);
}

.copy-btn.copied {
    background: rgba(52, 211, 153, 0.2);
    color: var(--color-tip);
    border-color: rgba(52, 211, 153, 0.4);
}

code {
    font-family: var(--font-mono);
    color: #c4b5fd;
    font-size: 0.88rem;
    background: rgba(139, 92, 246, 0.1);
    padding: 0.1em 0.4em;
    border-radius: 4px;
    border: 1px solid rgba(139, 92, 246, 0.15);
}

pre code {
    background: none;
    padding: 0;
    border: none;
    border-radius: 0;
    color: #d1d9e0;
    font-size: 0.88rem;
}

/* ============================================================
   Botones
   ============================================================ */
.btn-primary {
    position: relative;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1), rgba(255, 255, 255, 0.05));
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    padding: 0.8rem 1.6rem;
    border-radius: 99px;
    /* Pill shape */
    font-family: var(--font-sans);
    font-size: 0.975rem;
    font-weight: 600;
    cursor: pointer;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    z-index: 1;
}

.btn-primary::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 99px;
    padding: 2px;
    /* Border thickness */
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    background-size: 200% 100%;
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    mask-composite: exclude;
    opacity: 0;
    transition: opacity 0.4s ease;
    animation: borderFlow 3s linear infinite;
}

@keyframes borderFlow {
    0% {
        background-position: 200% 0;
    }

    100% {
        background-position: -200% 0;
    }
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: -1;
}

.btn-primary:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 10px 25px -5px rgba(139, 92, 246, 0.5);
    border-color: rgba(255, 255, 255, 0.4);
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.3), rgba(59, 130, 246, 0.3));
}

.btn-primary:hover::before {
    transform: translateX(200%);
}

.btn-primary:hover::after {
    opacity: 1;
}

.btn-primary:active {
    transform: translateY(1px) scale(0.98);
    box-shadow: 0 5px 10px -5px rgba(139, 92, 246, 0.5);
}

/* ============================================================
   Cajas Pedagógicas
   ============================================================ */

/* Resumen de lección */
.summary-box {
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.08), rgba(59, 130, 246, 0.06));
    border: 1px solid rgba(139, 92, 246, 0.3);
    border-radius: 14px;
    padding: 1.75rem;
    margin: 0 0 2.5rem;
    animation: popIn 0.4s ease forwards;
}

.summary-box h4 {
    color: var(--accent-primary);
    font-size: 0.82rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 700;
    margin: 0 0 1rem;
}

.summary-box ul {
    margin: 0 0 0 1.25rem;
    color: var(--text-primary);
    font-size: 1rem;
}

.summary-box li {
    margin-bottom: 0.35rem;
}

.lesson-meta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: center;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.06);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.difficulty-badge {
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.2rem 0.65rem;
    border-radius: 99px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.difficulty-badge.beginner {
    background: rgba(34, 197, 94, 0.12);
    color: var(--color-tip);
    border: 1px solid rgba(34, 197, 94, 0.3);
}

.difficulty-badge.intermediate {
    background: rgba(245, 158, 11, 0.12);
    color: var(--color-warning);
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.difficulty-badge.advanced {
    background: rgba(239, 68, 68, 0.12);
    color: var(--color-error);
    border: 1px solid rgba(239, 68, 68, 0.3);
}

/* Caja Concepto Clave (azul) */
.info-box {
    background: rgba(59, 130, 246, 0.07);
    border: 1px solid rgba(59, 130, 246, 0.3);
    border-left: 4px solid var(--color-info);
    border-radius: 10px;
    padding: 1.25rem 1.5rem;
    margin: 1.75rem 0;
}

.info-box .box-title {
    color: var(--color-info);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 0.6rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.info-box p,
.info-box li {
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 0.4rem;
}

.info-box ul {
    margin: 0.5rem 0 0 1.25rem;
}

/* Caja Consejo (verde) */
.tip-box {
    background: rgba(34, 197, 94, 0.07);
    border: 1px solid rgba(34, 197, 94, 0.3);
    border-left: 4px solid var(--color-tip);
    border-radius: 10px;
    padding: 1.25rem 1.5rem;
    margin: 1.75rem 0;
}

.tip-box .box-title {
    color: var(--color-tip);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 0.6rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.tip-box p,
.tip-box li {
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 0.4rem;
}

.tip-box ul {
    margin: 0.5rem 0 0 1.25rem;
}

/* Caja Advertencia (naranja) */
.warning-box {
    background: rgba(245, 158, 11, 0.07);
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-left: 4px solid var(--color-warning);
    border-radius: 10px;
    padding: 1.25rem 1.5rem;
    margin: 1.75rem 0;
}

.warning-box .box-title {
    color: var(--color-warning);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 0.6rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.warning-box p,
.warning-box li {
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 0.4rem;
}

.warning-box ul {
    margin: 0.5rem 0 0 1.25rem;
}

/* Caja Analogía (violeta) */
.analogy-box {
    background: rgba(139, 92, 246, 0.07);
    border: 1px solid rgba(139, 92, 246, 0.3);
    border-left: 4px solid var(--color-analogy);
    border-radius: 10px;
    padding: 1.25rem 1.5rem;
    margin: 1.75rem 0;
}

.analogy-box .box-title {
    color: var(--accent-primary);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 0.6rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.analogy-box p,
.analogy-box li {
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 0.4rem;
}

/* ============================================================
   Ejercicios Interactivos
   ============================================================ */
.exercise-box {
    background: rgba(0, 0, 0, 0.2);
    border: 1px dashed var(--accent-secondary);
    padding: 2rem;
    border-radius: 14px;
    margin: 2.5rem 0;
}

.exercise-box h3 {
    color: var(--accent-secondary);
    margin-top: 0;
    font-size: 1.1rem;
}

.input-group {
    margin-bottom: 1.25rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.92rem;
    font-weight: 500;
}

.input-group input,
.input-group textarea,
.input-group select {
    width: 100%;
    padding: 0.9rem 1rem;
    background: rgba(2, 6, 23, 0.7);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    resize: vertical;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-group input:focus,
.input-group textarea:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(139, 92, 246, 0.25);
}

.input-group select {
    font-family: var(--font-sans);
    cursor: pointer;
}

.output-area {
    margin-top: 1.25rem;
    padding: 1.25rem;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    min-height: 80px;
    transition: all 0.3s ease;
    font-size: 1rem;
    color: var(--text-secondary);
}

.success-anim {
    animation: successPulse 0.5s ease;
    border-color: #22c55e !important;
}

.error-anim {
    animation: shake 0.4s ease;
    border-color: #ef4444 !important;
}

/* ============================================================
   Sistema de Quiz
   ============================================================ */
.quiz-container {
    background: rgba(0, 0, 0, 0.25);
    border: 1px solid rgba(139, 92, 246, 0.3);
    border-radius: 16px;
    padding: 2rem;
    margin: 3rem 0 1rem;
    animation: slideDown 0.4s ease;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.75rem;
    flex-wrap: wrap;
    gap: 0.75rem;
    padding-bottom: 1.25rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.quiz-header h3 {
    color: var(--accent-primary);
    margin: 0;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.quiz-progress-text {
    font-size: 0.82rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.quiz-question-block {
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    animation: slideDown 0.3s ease;
}

.quiz-question-block:last-of-type {
    border-bottom: none;
}

.quiz-question-num {
    font-size: 0.72rem;
    color: var(--accent-primary);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    display: block;
    margin-bottom: 0.5rem;
}

.quiz-question-text {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
    line-height: 1.55;
    text-align: justify;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 0.55rem;
}

.quiz-option {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 0.85rem 1.1rem;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    color: var(--text-secondary);
    text-align: left;
    transition: all 0.2s ease;
    line-height: 1.5;
    width: 100%;
}

.quiz-option:hover:not(:disabled) {
    background: rgba(139, 92, 246, 0.12);
    border-color: var(--accent-primary);
    color: var(--text-primary);
    transform: translateX(6px);
    box-shadow: 4px 0 15px rgba(139, 92, 246, 0.1);
}

.option-letter {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    border-radius: 8px;
    /* Square-ish with smooth corners for a modern look */
    background: rgba(255, 255, 255, 0.08);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    font-weight: 800;
    color: var(--text-secondary);
    transition: all 0.25s var(--transition-smooth);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.quiz-option.correct {
    background: rgba(34, 197, 94, 0.12);
    border-color: var(--color-tip);
    color: var(--text-primary);
    cursor: default;
}

.quiz-option.correct .option-letter {
    background: var(--color-tip);
    color: white;
}

.quiz-option.incorrect {
    background: rgba(239, 68, 68, 0.1);
    border-color: var(--color-error);
    color: var(--text-secondary);
    cursor: default;
}

.quiz-option.incorrect .option-letter {
    background: var(--color-error);
    color: white;
}

.quiz-option:disabled {
    cursor: default;
    transform: none !important;
}

.quiz-feedback {
    margin-top: 0.875rem;
    padding: 0.875rem 1.1rem;
    border-radius: 8px;
    font-size: 0.92rem;
    line-height: 1.6;
    text-align: justify;
    animation: slideDown 0.25s ease;
    display: none;
}

.quiz-feedback.correct {
    background: rgba(34, 197, 94, 0.1);
    border: 1px solid rgba(34, 197, 94, 0.3);
    color: #bbf7d0;
    display: block;
}

.quiz-feedback.incorrect {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #fecaca;
    display: block;
}

.quiz-feedback strong {
    color: inherit;
}

.quiz-final-score {
    text-align: center;
    padding: 2rem 1rem;
    border-radius: 12px;
    margin-top: 1.5rem;
    animation: popIn 0.4s ease;
}

.quiz-final-score.perfect {
    background: rgba(34, 197, 94, 0.1);
    border: 1px solid rgba(34, 197, 94, 0.3);
}

.quiz-final-score.good {
    background: rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.3);
}

.quiz-final-score.needs-work {
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.quiz-score-number {
    font-size: 2.75rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
}

.quiz-final-score.perfect .quiz-score-number {
    color: var(--color-tip);
}

.quiz-final-score.good .quiz-score-number {
    color: var(--color-info);
}

.quiz-final-score.needs-work .quiz-score-number {
    color: var(--color-warning);
}

.quiz-score-msg {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 1.25rem;
}

.quiz-retry-btn {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    padding: 0.6rem 1.4rem;
    border-radius: 8px;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.quiz-retry-btn:hover {
    background: rgba(139, 92, 246, 0.15);
    border-color: var(--accent-primary);
}

/* ============================================================
   Tabs de Código (HTML / Jinja / Output)
   ============================================================ */
.code-tabs {
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    overflow: hidden;
    margin: 1.75rem 0;
    background: var(--code-bg);
}

.code-tabs-header {
    display: flex;
    background: rgba(255, 255, 255, 0.04);
    border-bottom: 1px solid var(--glass-border);
    overflow-x: auto;
}

.code-tab-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 0.7rem 1.25rem;
    font-family: var(--font-sans);
    font-size: 0.82rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    border-bottom: 2px solid transparent;
    white-space: nowrap;
    letter-spacing: 0.03em;
}

.code-tab-btn:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.04);
}

.code-tab-btn.active {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
    background: rgba(139, 92, 246, 0.08);
}

.code-tab-content {
    display: none;
    padding: 1.25rem;
}

.code-tab-content.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

.code-tab-content pre {
    margin: 0;
    border: none;
    background: transparent;
    padding: 0;
}

/* ============================================================
   Preview Panel Jinja
   ============================================================ */
.jinja-preview {
    background: linear-gradient(135deg, rgba(6, 182, 212, 0.06), rgba(20, 184, 166, 0.04));
    border: 1px solid rgba(6, 182, 212, 0.25);
    border-radius: 12px;
    padding: 1.5rem;
    margin: 1.75rem 0;
    position: relative;
}

.jinja-preview::before {
    content: '⚡ Jinja Output';
    position: absolute;
    top: -0.65rem;
    left: 1rem;
    background: var(--bg-secondary);
    padding: 0 0.6rem;
    font-size: 0.72rem;
    font-weight: 700;
    color: #06b6d4;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.jinja-preview-output {
    font-family: var(--font-mono);
    font-size: 0.92rem;
    color: #5eead4;
    line-height: 1.7;
    white-space: pre-wrap;
    word-break: break-word;
}

/* ============================================================
   Highlights de Sintaxis Jinja (Inline)
   ============================================================ */
.jinja-var {
    background: rgba(6, 182, 212, 0.12);
    color: #22d3ee;
    padding: 0.1rem 0.4rem;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.88rem;
    font-weight: 500;
    border: 1px solid rgba(6, 182, 212, 0.2);
}

.jinja-tag {
    background: rgba(251, 146, 60, 0.12);
    color: #fb923c;
    padding: 0.1rem 0.4rem;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.88rem;
    font-weight: 500;
    border: 1px solid rgba(251, 146, 60, 0.2);
}

.jinja-comment {
    background: rgba(148, 163, 184, 0.1);
    color: #94a3b8;
    padding: 0.1rem 0.4rem;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.88rem;
    font-style: italic;
    border: 1px solid rgba(148, 163, 184, 0.15);
}

/* ============================================================
   Panel de Contexto JSON
   ============================================================ */
.context-panel {
    background: rgba(139, 92, 246, 0.06);
    border: 1px solid rgba(139, 92, 246, 0.25);
    border-radius: 12px;
    padding: 1.25rem 1.5rem;
    margin: 1.5rem 0;
    position: relative;
}

.context-panel::before {
    content: '📦 Contexto (Variables)';
    position: absolute;
    top: -0.65rem;
    left: 1rem;
    background: var(--bg-secondary);
    padding: 0 0.6rem;
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--accent-primary);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.context-panel pre {
    margin: 0;
    border: none;
    background: transparent;
    padding: 0;
}

.context-panel code {
    color: #c4b5fd;
    font-size: 0.88rem;
}

/* ============================================================
   Jinja Interactive Playground
   ============================================================ */
.jinja-playground {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin: 1.75rem 0;
}

.jinja-playground-input,
.jinja-playground-output {
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    overflow: hidden;
}

.jinja-playground-label {
    padding: 0.6rem 1rem;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    border-bottom: 1px solid var(--glass-border);
}

.jinja-playground-input .jinja-playground-label {
    background: rgba(251, 146, 60, 0.08);
    color: #fb923c;
}

.jinja-playground-output .jinja-playground-label {
    background: rgba(6, 182, 212, 0.08);
    color: #06b6d4;
}

.jinja-playground textarea {
    width: 100%;
    min-height: 120px;
    padding: 1rem;
    background: var(--code-bg);
    border: none;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.88rem;
    resize: vertical;
    outline: none;
}

.jinja-playground-result {
    padding: 1rem;
    background: var(--code-bg);
    min-height: 120px;
    font-family: var(--font-mono);
    font-size: 0.88rem;
    color: #5eead4;
    white-space: pre-wrap;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .jinja-playground {
        grid-template-columns: 1fr;
    }
}

/* ============================================================
   Tabla de Referencia estilizada
   ============================================================ */
.reference-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    margin: 1.5rem 0;
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--glass-border);
}

.reference-table thead tr {
    background: rgba(139, 92, 246, 0.12);
}

.reference-table th {
    padding: 0.85rem 1rem;
    text-align: left;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 0.82rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid rgba(139, 92, 246, 0.2);
}

.reference-table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.04);
    color: var(--text-secondary);
}

.reference-table tbody tr:hover {
    background: rgba(255, 255, 255, 0.03);
}

.reference-table code {
    font-size: 0.85rem;
}

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 992px) {
    .sidebar {
        transform: translateX(-100%);
        width: 280px;
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
        max-width: 100vw;
    }

    .menu-btn {
        display: block;
    }

    .content-area {
        margin: 1rem;
        padding: 1.25rem;
    }

    .lesson-nav {
        margin: 1rem 1.25rem 1.25rem;
    }
}

@media (max-width: 576px) {
    .content-area {
        margin: 0.5rem;
        padding: 1rem;
        border-radius: 12px;
    }

    .topbar {
        padding: 0 1.25rem;
        height: 64px;
    }

    .content-area h2 {
        font-size: 1.65rem;
    }

    .lesson-nav {
        flex-direction: column;
        align-items: stretch;
        margin: 1rem 0.75rem;
    }

    .lesson-nav-btn {
        max-width: 100%;
    }

    .quiz-container {
        padding: 1.25rem;
    }
}

/* ============================================================
   Splash Screen De Carga
   ============================================================ */
.initial-splash {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: #0f172a;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: opacity 0.6s ease;
    font-family: 'Inter', sans-serif;
}

.splash-spinner {
    width: 80px;
    height: 80px;
    border: 4px solid rgba(139, 92, 246, 0.1);
    border-top-color: #8b5cf6;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 2rem;
}

.splash-title {
    color: white;
    font-weight: 700;
    letter-spacing: -1px;
    margin: 0;
}

.splash-accent {
    color: #8b5cf6;
}

.splash-text {
    color: #64748b;
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* ─── Indicador de Sincronización ─── */
.topbar-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.sync-status {
    font-size: 1.2rem;
    cursor: help;
    transition: all 0.3s ease;
    filter: drop-shadow(0 0 5px rgba(255, 255, 255, 0.2));
}

.sync-status.syncing {
    animation: syncRotate 2s infinite linear;
    color: var(--gl-accent);
}

.sync-status.synced {
    color: #10b981;
    filter: drop-shadow(0 0 8px rgba(16, 185, 129, 0.4));
}

@keyframes syncRotate {
    0% {
        transform: rotate(0deg) scale(1);
        opacity: 0.7;
    }

    50% {
        transform: rotate(180deg) scale(1.2);
        opacity: 1;
    }

    100% {
        transform: rotate(360deg) scale(1);
        opacity: 0.7;
    }
}