/* ============================================================================
   ESTILOS GENERALES - INGLÉS CON MATI (HTML + PHP PURO)
   Conserva la estética original Libre Baskerville + Gradientes + Tarjetas
   ============================================================================ */
@import url('https://fonts.googleapis.com/css2?family=Libre+Baskerville:ital,wght@0,400;0,700;1,400&family=Inter:wght@400;500;600;700&display=swap');

:root {
    --font-primary: 'Libre Baskerville', Georgia, serif;
    --font-ui: 'Inter', system-ui, -apple-system, sans-serif;
    --color-brand: #6200ff;
    --color-brand-hover: #4700ba;
    --color-cyan: #00eaff;
    --color-dark: #0d141a;
    --color-footer: #263238;
    --color-text: #1a1a1a;
    --color-muted: #4b5563;
    --color-border: #e5e7eb;
    --color-bg: #ffffff;
    --color-surface: #f8fafc;
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    color: inherit;
    transition: color 0.2s ease;
}

img {
    max-width: 100%;
    height: auto;
}

/* ============================================================================
   HEADER Y NAVEGACIÓN PRINCIPAL (Idéntico al diseño original + Barra de Usuario)
   ============================================================================ */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: #ffffff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.07);
}

.site-header__inner {
    max-width: 1240px;
    margin: 0 auto;
    padding: 12px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    flex-wrap: wrap;
}

.site-header__logo {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--color-brand);
    font-family: var(--font-primary);
    font-weight: 700;
    font-size: 1.35rem;
}

.site-header__logo img {
    height: 54px;
    width: auto;
    object-fit: contain;
}

.site-nav {
    display: flex;
    align-items: center;
    gap: 32px;
    list-style: none;
    flex-wrap: wrap;
}

.site-nav__item {
    position: relative;
}

.site-nav__link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-family: var(--font-primary);
    font-size: 16px;
    color: var(--color-dark);
    text-decoration: none;
    padding: 8px 0;
    cursor: pointer;
}

.site-nav__link:hover,
.site-nav__link--active {
    color: var(--color-brand-hover);
    text-decoration: underline;
    text-underline-offset: 6px;
}

.site-nav__dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 240px;
    background: #ffffff;
    border-radius: 8px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.14);
    border: 1px solid var(--color-border);
    padding: 12px 0;
    list-style: none;
    display: none;
    z-index: 120;
}

.site-nav__item:hover .site-nav__dropdown,
.site-nav__item:focus-within .site-nav__dropdown {
    display: block;
}

.site-nav__dropdown li a {
    display: block;
    padding: 9px 20px;
    font-size: 15px;
    color: var(--color-dark);
    text-decoration: none;
}

.site-nav__dropdown li a:hover {
    background: #f5f3ff;
    color: var(--color-brand);
}

.site-header__actions {
    display: flex;
    align-items: center;
    gap: 14px;
    font-family: var(--font-ui);
}

.social-links {
    display: flex;
    align-items: center;
    gap: 12px;
}

.social-links a {
    display: inline-flex;
    color: #0d141a;
    transition: color 0.2s, transform 0.2s;
}

.social-links a:hover {
    color: var(--color-brand);
    transform: translateY(-1px);
}

.auth-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border-radius: 999px;
    font-family: var(--font-ui);
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s ease;
    cursor: pointer;
}

.auth-btn--login {
    color: var(--color-dark);
    border: 1.5px solid var(--color-dark);
    background: #ffffff;
}

.auth-btn--login:hover {
    background: #f1f5f9;
}

.auth-btn--register {
    background: var(--color-brand);
    color: #ffffff;
    border: 1.5px solid var(--color-brand);
}

.auth-btn--register:hover {
    background: var(--color-brand-hover);
}

.auth-user-pill {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: #f3e8ff;
    color: var(--color-brand-hover);
    padding: 7px 14px;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    border: 1px solid #d8b4fe;
}

.auth-user-pill:hover {
    background: #e9d5ff;
}

.mobile-menu-btn {
    display: none;
    background: transparent;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    padding: 8px 12px;
    font-size: 18px;
    cursor: pointer;
}

@media (max-width: 960px) {
    .mobile-menu-btn {
        display: inline-flex;
    }
    .site-nav {
        display: none;
        width: 100%;
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
        padding-top: 12px;
        border-top: 1px solid var(--color-border);
    }
    .site-nav.open {
        display: flex;
    }
    .site-nav__dropdown {
        position: static;
        box-shadow: none;
        border: none;
        border-left: 2px solid var(--color-brand);
        margin-left: 12px;
        padding: 4px 0;
        display: block;
    }
}

/* ============================================================================
   HERO / HOME Y SECCIONES GENERALES
   ============================================================================ */
.hero-home {
    background: linear-gradient(180deg, #ffffff 0%, rgba(0, 234, 255, 0.22) 100%);
    padding: 56px 20px 72px;
}

.hero-home__grid {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: 48px;
    align-items: center;
}

.hero-home__title {
    font-size: 46px;
    line-height: 1.25;
    margin-bottom: 24px;
    color: var(--color-dark);
}

.hero-home__text p {
    font-size: 21px;
    line-height: 1.45;
    margin-bottom: 18px;
    color: var(--color-dark);
}

.hero-home__actions {
    margin-top: 28px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    max-width: 380px;
}

.btn-mati {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 15px 28px;
    font-family: var(--font-primary);
    font-size: 19px;
    font-weight: 700;
    color: var(--color-dark);
    background: #ffffff;
    border: 3px solid var(--color-dark);
    border-radius: 10px;
    text-decoration: none;
    transition: all 0.2s ease;
    cursor: pointer;
    text-align: center;
}

.btn-mati:hover {
    background: var(--color-brand);
    color: #ffffff;
    border-color: #000000;
}

.btn-mati--purple {
    background: var(--color-brand);
    color: #ffffff;
    border-color: var(--color-dark);
}

.btn-mati--purple:hover {
    background: var(--color-brand-hover);
}

.hero-home__image-wrap {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 18px;
}

.hero-home__image {
    width: 100%;
    max-width: 460px;
    border-radius: 140px;
    object-fit: cover;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.12);
}

@media (max-width: 860px) {
    .hero-home__grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
    .hero-home__actions {
        margin-left: auto;
        margin-right: auto;
    }
    .hero-home__title {
        font-size: 34px;
    }
}

/* ============================================================================
   ENCABEZADOS DE CATEGORÍA Y LECCIÓN
   ============================================================================ */
.category-banner {
    background: linear-gradient(0deg, #ffffff 0%, rgb(0, 234, 255) 100%);
    padding: 44px 20px 32px;
    text-align: center;
}

.category-banner h1 {
    font-size: 42px;
    font-weight: 700;
    color: var(--color-dark);
    max-width: 960px;
    margin: 0 auto;
}

.category-banner p {
    margin-top: 10px;
    font-size: 18px;
    color: #1e293b;
    max-width: 760px;
    margin-left: auto;
    margin-right: auto;
}

.lesson-header {
    max-width: 954px;
    margin: 0 auto;
    padding: 42px 24px 24px;
    text-align: center;
    border-bottom: 1px solid var(--color-border);
}

.lesson-header__title {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 12px;
    color: #000000;
}

.lesson-header__description {
    font-size: 18px;
    color: #334155;
    margin-bottom: 12px;
}

.lesson-header__meta {
    font-family: var(--font-ui);
    font-size: 14px;
    color: #64748b;
}

.lesson-container {
    max-width: 960px;
    margin: 0 auto;
    padding: 36px 24px 64px;
}

.lesson-content {
    font-size: 18px;
    line-height: 1.65;
}

.lesson-content h1,
.lesson-content h2,
.lesson-content h3,
.lesson-content h4 {
    margin-top: 1.2em;
    margin-bottom: 0.6em;
    line-height: 1.35;
}

.lesson-content p {
    margin-bottom: 14px;
}

.lesson-content ul,
.lesson-content ol {
    padding-left: 28px;
    margin-bottom: 18px;
}

.lesson-content li {
    margin-bottom: 6px;
}

.lesson-content a {
    color: var(--color-brand);
    font-weight: 700;
    text-decoration: underline;
}

.lesson-images-grid {
    display: flex;
    flex-direction: column;
    gap: 28px;
    align-items: center;
    margin: 24px 0;
}

.lesson-images-grid img {
    max-width: 820px;
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.08);
    border: 1px solid var(--color-border);
}

/* ============================================================================
   GRILLA DE TARJETAS DE LECCIONES Y CATEGORÍAS
   ============================================================================ */
.cards-section {
    background: linear-gradient(180deg, #ffffff 0%, rgba(0, 234, 255, 0.35) 100%);
    padding: 48px 24px 80px;
    flex: 1;
}

.cards-grid {
    max-width: 1224px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 28px;
}

.topic-card {
    background: #ffffff;
    border-radius: 14px;
    padding: 26px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.05);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.topic-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 14px 28px rgba(98, 0, 255, 0.1);
    border-color: var(--color-brand);
}

.topic-card__badge-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
    font-family: var(--font-ui);
}

.topic-card__category {
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--color-brand);
    background: #f3e8ff;
    padding: 4px 10px;
    border-radius: 999px;
}

.topic-card__status {
    font-size: 12px;
    font-weight: 700;
    color: #065f46;
    background: #d1fae5;
    padding: 4px 10px;
    border-radius: 999px;
}

.topic-card__title {
    font-size: 24px;
    font-weight: 700;
    color: var(--color-dark);
    margin-bottom: 10px;
    line-height: 1.3;
}

.topic-card__title a {
    text-decoration: none;
}

.topic-card__title a:hover {
    color: var(--color-brand);
}

.topic-card__desc {
    font-size: 15px;
    color: var(--color-muted);
    margin-bottom: 20px;
    line-height: 1.55;
}

.topic-card__actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: auto;
    padding-top: 14px;
    border-top: 1px solid #f1f5f9;
    font-family: var(--font-ui);
}

.topic-card__btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.btn-card-leccion {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 9px 14px;
    font-size: 14px;
    font-weight: 600;
    color: var(--color-dark);
    background: #f1f5f9;
    border: 1px solid #cbd5e1;
    border-radius: 8px;
    text-decoration: none;
    flex: 1;
}

.btn-card-leccion:hover {
    background: #e2e8f0;
}

.btn-ejercicio-chip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 9px 14px;
    font-family: var(--font-ui);
    font-size: 14px;
    font-weight: 600;
    border-radius: 8px;
    text-decoration: none;
    background: #ede9fe;
    color: var(--color-brand-hover);
    border: 1px solid #c4b5fd;
    transition: all 0.15s ease;
    flex: 1;
}

.btn-ejercicio-chip--primary {
    background: var(--color-brand);
    color: #ffffff;
    border-color: var(--color-brand);
}

.btn-ejercicio-chip:hover {
    background: var(--color-brand-hover);
    color: #ffffff;
}

.topic-card__file-hint {
    font-family: monospace;
    font-size: 11.5px;
    color: #64748b;
    background: #f8fafc;
    padding: 5px 8px;
    border-radius: 6px;
    border: 1px dashed #cbd5e1;
    word-break: break-all;
}

/* ============================================================================
   CAJA DE EJERCICIOS AL FINAL DE CADA LECCIÓN
   ============================================================================ */
.lesson-exercise-box {
    margin-top: 44px;
    padding: 28px;
    border-radius: 16px;
    background: linear-gradient(135deg, #f5f3ff 0%, #e0f2fe 100%);
    border: 2px solid var(--color-brand);
    box-shadow: 0 12px 24px rgba(98, 0, 255, 0.08);
    font-family: var(--font-ui);
}

.lesson-exercise-box__badge {
    display: inline-block;
    background: var(--color-brand);
    color: #ffffff;
    font-size: 12px;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 999px;
    margin-bottom: 10px;
}

.lesson-exercise-box__title {
    font-family: var(--font-primary);
    font-size: 26px;
    color: var(--color-dark);
    margin-bottom: 8px;
}

.lesson-exercise-box__desc {
    font-size: 15.5px;
    color: #334155;
    margin-bottom: 20px;
}

.lesson-exercise-box__buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
}

.btn-ejercicio-tema {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 13px 24px;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 700;
    text-decoration: none;
    transition: all 0.2s ease;
}

.btn-ejercicio-tema--primary {
    background: var(--color-brand);
    color: #ffffff;
    border: 2px solid var(--color-dark);
}

.btn-ejercicio-tema--primary:hover {
    background: var(--color-brand-hover);
    transform: translateY(-2px);
}

.btn-ejercicio-tema--secondary {
    background: #ffffff;
    color: var(--color-brand);
    border: 2px solid var(--color-brand);
}

.btn-ejercicio-tema--secondary:hover {
    background: var(--color-brand);
    color: #ffffff;
}

.btn-ejercicio-directo {
    display: inline-flex;
    align-items: center;
    padding: 10px 14px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 600;
    color: #475569;
    background: rgba(255, 255, 255, 0.8);
    border: 1px solid #cbd5e1;
    text-decoration: none;
}

.btn-ejercicio-directo:hover {
    background: #ffffff;
    color: var(--color-dark);
}

.lesson-exercise-box__path-hint {
    margin-top: 16px;
    padding-top: 12px;
    border-top: 1px dashed #cbd5e1;
    font-size: 13px;
    color: #475569;
}

.lesson-exercise-box__path-hint code {
    background: #ffffff;
    padding: 2px 6px;
    border-radius: 4px;
    border: 1px solid #cbd5e1;
    color: var(--color-brand-hover);
    font-weight: 600;
}

/* ============================================================================
   FILTROS DE TEMÁTICAS EN LA PÁGINA DE EJERCICIOS
   ============================================================================ */
.filter-bar {
    max-width: 1224px;
    margin: 0 auto 32px;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    font-family: var(--font-ui);
}

.filter-btn {
    padding: 10px 18px;
    border-radius: 999px;
    border: 1.5px solid #cbd5e1;
    background: #ffffff;
    color: var(--color-dark);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

.filter-btn:hover,
.filter-btn.active {
    background: var(--color-brand);
    color: #ffffff;
    border-color: var(--color-brand);
}

.category-section-block {
    max-width: 1224px;
    margin: 0 auto 48px;
}

.category-section-block__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--color-brand);
}

.category-section-block__title {
    font-size: 28px;
    color: var(--color-dark);
}

.category-section-block__folder {
    font-family: monospace;
    font-size: 13px;
    background: #ffffff;
    padding: 6px 12px;
    border-radius: 999px;
    border: 1px solid #cbd5e1;
    color: var(--color-brand-hover);
}

/* ============================================================================
   FORMULARIOS DE REGISTRO, LOGIN Y PERFIL DE USUARIO
   ============================================================================ */
.auth-page {
    flex: 1;
    background: linear-gradient(180deg, #ffffff 0%, rgba(0, 234, 255, 0.25) 100%);
    padding: 48px 20px 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.auth-card {
    width: 100%;
    max-width: 480px;
    background: #ffffff;
    border-radius: 16px;
    padding: 36px 32px;
    box-shadow: 0 16px 36px rgba(0, 0, 0, 0.08);
    border: 1px solid var(--color-border);
    font-family: var(--font-ui);
}

.auth-card h1 {
    font-family: var(--font-primary);
    font-size: 28px;
    margin-bottom: 8px;
    color: var(--color-dark);
    text-align: center;
}

.auth-card p.subtitle {
    text-align: center;
    color: var(--color-muted);
    font-size: 14.5px;
    margin-bottom: 24px;
}

.form-group {
    margin-bottom: 18px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--color-dark);
    margin-bottom: 6px;
}

.form-control {
    width: 100%;
    padding: 11px 14px;
    font-size: 15px;
    border: 1.5px solid #cbd5e1;
    border-radius: 8px;
    outline: none;
    transition: border-color 0.2s;
    font-family: var(--font-ui);
}

.form-control:focus {
    border-color: var(--color-brand);
}

.alert {
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 14px;
    margin-bottom: 18px;
    font-weight: 500;
}

.alert--error {
    background: #fef2f2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.alert--success {
    background: #ecfdf5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

/* ============================================================================
   FOOTER Y BOTÓN FLOTANTE DE WHATSAPP
   ============================================================================ */
.site-footer {
    background: var(--color-footer);
    color: #ffffff;
    padding: 40px 24px;
    margin-top: auto;
}

.site-footer__inner {
    max-width: 1224px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 24px;
}

.site-footer__contact a {
    color: #ffffff;
    text-decoration: none;
    font-size: 20px;
    font-weight: 700;
    display: block;
}

.site-footer__contact a:hover {
    color: var(--color-cyan);
}

.whatsapp-float {
    position: fixed;
    right: 22px;
    bottom: 22px;
    z-index: 95;
    background: #25d366;
    color: #ffffff;
    width: 58px;
    height: 58px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.22);
    text-decoration: none;
    transition: transform 0.2s ease;
}

.whatsapp-float:hover {
    transform: scale(1.08);
}