/* ============================================================
   IT-Tea.org — Lesson Page Styles
   Shared styles for all lesson material pages
   ============================================================ */

/* ---------- Layout ---------- */
.lesson-page {
    padding-top: calc(var(--header-height) + var(--space-lg));
    min-height: 100vh;
}

.lesson-container {
    max-width: 860px;
    margin: 0 auto;
    padding: 0 var(--space-md) var(--space-2xl);
}

/* ---------- Breadcrumb ---------- */
.lesson-breadcrumb {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: var(--space-lg);
    flex-wrap: wrap;
}

.lesson-breadcrumb a {
    color: var(--clr-tea);
    text-decoration: none;
    transition: opacity var(--transition);
}

.lesson-breadcrumb a:hover {
    opacity: 0.7;
}

.lesson-breadcrumb .sep {
    margin: 0 var(--space-2xs);
}

/* ---------- Page Header ---------- */
.lesson-header {
    margin-bottom: var(--space-xl);
}

.lesson-unit-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-sm);
    background: var(--bg-glass);
    color: var(--clr-tea);
    border: 1px solid var(--border);
    margin-bottom: var(--space-sm);
}

.lesson-title {
    font-size: clamp(1.8rem, 4vw, 2.4rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
    line-height: 1.15;
}

.lesson-intro {
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--space-lg);
}

/* ---------- LO Card ---------- */
.lesson-lo-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-left: 4px solid var(--clr-tea);
    border-radius: var(--radius-md);
    padding: var(--space-md) var(--space-lg);
    margin-bottom: var(--space-lg);
}

.lesson-lo-card h3 {
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--clr-tea);
    margin-bottom: var(--space-sm);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.lesson-lo-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.lesson-lo-list li {
    display: flex;
    gap: var(--space-sm);
    padding: var(--space-xs) 0;
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.lesson-lo-list .lo-code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.78rem;
    font-weight: 600;
    background: rgba(13, 148, 136, 0.12);
    color: var(--clr-tea);
    padding: 0.15em 0.5em;
    border-radius: var(--radius-sm);
    white-space: nowrap;
    height: fit-content;
    margin-top: 0.1em;
}

/* ---------- PDF Presentation ---------- */
.lesson-pdf-block {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-bottom: var(--space-xl);
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
}

.lesson-pdf-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    background: var(--accent-warm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.lesson-pdf-info {
    flex: 1;
    min-width: 180px;
}

.lesson-pdf-info h4 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-2xs);
}

.lesson-pdf-info p {
    font-size: 0.82rem;
    color: var(--text-muted);
}

.lesson-pdf-actions {
    display: flex;
    gap: var(--space-sm);
}

.lesson-pdf-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-md);
    font-size: 0.82rem;
    font-weight: 600;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all var(--transition);
}

.lesson-pdf-btn.view-btn {
    background: var(--bg-glass);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.lesson-pdf-btn.view-btn:hover {
    border-color: var(--clr-tea);
    color: var(--clr-tea);
}

.lesson-pdf-btn.download-btn {
    background: var(--accent-tea);
    color: #fff;
}

.lesson-pdf-btn.download-btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

/* ---------- YouTube Video Block ---------- */
.lesson-video-block {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-bottom: var(--space-xl);
}

.lesson-video-header {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
}

.lesson-video-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    background: #ff0000;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.lesson-video-info h4 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-2xs);
}

.lesson-video-info p {
    font-size: 0.82rem;
    color: var(--text-muted);
}

.lesson-video-wrapper {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
}

.lesson-video-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

/* ---------- Lesson Image ---------- */
.lesson-image-block {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--space-md);
    margin-bottom: var(--space-xl);
    text-align: center;
}

.lesson-image-block img {
    max-width: 100%;
    width: auto;
    max-height: 420px;
    height: auto;
    border-radius: var(--radius-md);
    cursor: zoom-in;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.lesson-image-block img:hover {
    transform: scale(1.02);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.lesson-image-block figcaption {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-top: var(--space-sm);
    font-style: italic;
}

/* Lightbox overlay */
.image-lightbox {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: rgba(0, 0, 0, 0.88);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: zoom-out;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.image-lightbox.active {
    opacity: 1;
    visibility: visible;
}

.image-lightbox img {
    max-width: 92vw;
    max-height: 92vh;
    border-radius: var(--radius-md);
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.5);
    transform: scale(0.92);
    transition: transform 0.3s ease;
}

.image-lightbox.active img {
    transform: scale(1);
}

.image-lightbox-close {
    position: absolute;
    top: 16px;
    right: 24px;
    color: #fff;
    font-size: 2rem;
    background: none;
    border: none;
    cursor: pointer;
    opacity: 0.7;
    transition: opacity 0.2s;
    line-height: 1;
}

.image-lightbox-close:hover {
    opacity: 1;
}

/* ---------- Section Blocks ---------- */
.lesson-section {
    margin-bottom: var(--space-xl);
}

.lesson-section-title {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-md);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.lesson-section-title i {
    color: var(--clr-tea);
    font-size: 1.1rem;
}

/* Analogy box */
.analogy-box {
    background: linear-gradient(135deg, rgba(13, 148, 136, 0.06), rgba(6, 182, 212, 0.06));
    border: 1px solid rgba(13, 148, 136, 0.2);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-bottom: var(--space-md);
}

.analogy-box h4 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--clr-tea);
    margin-bottom: var(--space-sm);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.analogy-box p {
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.65;
}

/* Theory Tables */
.theory-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: var(--space-md);
    font-size: 0.88rem;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--border);
}

.theory-table th {
    background: var(--bg-glass);
    font-weight: 700;
    text-align: left;
    padding: var(--space-sm) var(--space-md);
    color: var(--text-primary);
    border-bottom: 2px solid var(--border);
    font-size: 0.82rem;
    letter-spacing: 0.03em;
}

.theory-table td {
    padding: var(--space-sm) var(--space-md);
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
    line-height: 1.5;
}

.theory-table tr:last-child td {
    border-bottom: none;
}

.theory-table tr:hover td {
    background: var(--bg-glass);
}

.theory-table code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82em;
    background: var(--bg-code);
    padding: 0.15em 0.4em;
    border-radius: 4px;
}

/* Concept text */
.concept-text {
    font-size: 0.93rem;
    line-height: 1.75;
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
}

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

/* Concept list */
.concept-list {
    list-style: none;
    padding: 0;
    margin: 0 0 var(--space-md);
}

.concept-list li {
    position: relative;
    padding: var(--space-xs) 0 var(--space-xs) var(--space-lg);
    font-size: 0.92rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

.concept-list li::before {
    content: '●';
    position: absolute;
    left: 0;
    color: var(--clr-tea);
    font-size: 0.6em;
    top: 0.85em;
}

/* Definition list */
.definition-grid {
    display: grid;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.definition-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
}

.definition-item dt {
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--text-primary);
    margin-bottom: var(--space-2xs);
}

.definition-item dd {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

/* ---------- Worked Example ---------- */
.worked-example {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    margin-bottom: var(--space-md);
}

.worked-example h4 {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.worked-example h4 .step-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    background: var(--accent-tea);
    color: #fff;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.worked-example p,
.worked-example ul {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.65;
}

.worked-example code,
.code-block code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82em;
}

/* Code block */
.code-block {
    background: var(--bg-code);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    margin: var(--space-sm) 0;
    overflow-x: auto;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    line-height: 1.7;
    color: var(--text-primary);
    border: 1px solid var(--border);
    white-space: pre-wrap;
    word-wrap: break-word;
}

.code-block code {
    white-space: pre;
    display: block;
}

/* ---------- Pitfalls / Notes ---------- */
.pitfall-box,
.note-box,
.pro-tip-box {
    border-radius: var(--radius-md);
    padding: var(--space-md) var(--space-lg);
    margin-bottom: var(--space-md);
    font-size: 0.9rem;
    line-height: 1.65;
}

.pitfall-box {
    background: rgba(239, 68, 68, 0.06);
    border: 1px solid rgba(239, 68, 68, 0.2);
    border-left: 4px solid #ef4444;
}

.pitfall-box h4 {
    color: #ef4444;
}

.note-box {
    background: rgba(59, 130, 246, 0.06);
    border: 1px solid rgba(59, 130, 246, 0.2);
    border-left: 4px solid #3b82f6;
}

.note-box h4 {
    color: #3b82f6;
}

.pro-tip-box {
    background: rgba(245, 158, 11, 0.06);
    border: 1px solid rgba(245, 158, 11, 0.2);
    border-left: 4px solid #f59e0b;
}

.pro-tip-box h4 {
    color: #f59e0b;
}

.pitfall-box h4,
.note-box h4,
.pro-tip-box h4 {
    font-size: 0.85rem;
    font-weight: 700;
    margin-bottom: var(--space-sm);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.pitfall-box p,
.note-box p,
.pro-tip-box p {
    color: var(--text-secondary);
    margin: 0;
}

.pitfall-box ul,
.note-box ul,
.pro-tip-box ul {
    padding-left: var(--space-lg);
    margin: var(--space-xs) 0 0;
    color: var(--text-secondary);
}

/* ---------- Assessment ---------- */
.assessment-tasks {
    counter-reset: task;
}

.task-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md) var(--space-lg);
    margin-bottom: var(--space-sm);
    counter-increment: task;
    position: relative;
    padding-left: calc(var(--space-lg) + 36px);
}

.task-item::before {
    content: counter(task);
    position: absolute;
    left: var(--space-md);
    top: var(--space-md);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    font-weight: 700;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--accent-tea);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
}

.task-item p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

.task-level {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: 0.15em 0.5em;
    border-radius: var(--radius-sm);
    margin-bottom: var(--space-xs);
}

.task-level.remember {
    background: rgba(59, 130, 246, 0.12);
    color: #3b82f6;
}

.task-level.understand {
    background: rgba(16, 185, 129, 0.12);
    color: #10b981;
}

.task-level.apply {
    background: rgba(245, 158, 11, 0.12);
    color: #f59e0b;
}

.task-level.analyze {
    background: rgba(139, 92, 246, 0.12);
    color: #8b5cf6;
}

.task-level.create {
    background: rgba(239, 68, 68, 0.12);
    color: #ef4444;
}

/* Self-check quiz */
.quiz-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    margin-bottom: var(--space-sm);
}

.quiz-question {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.quiz-answer {
    font-size: 0.88rem;
    color: transparent;
    cursor: pointer;
    padding: var(--space-sm);
    background: var(--bg-glass);
    border-radius: var(--radius-sm);
    transition: all var(--transition);
    user-select: none;
    position: relative;
}

.quiz-answer::before {
    content: '🔒 Click to reveal answer';
    color: var(--text-muted);
    font-size: 0.82rem;
    font-style: italic;
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    padding: var(--space-sm);
    transition: opacity var(--transition);
}

.quiz-answer:hover {
    background: var(--bg-code);
}

.quiz-answer.revealed {
    color: var(--clr-tea);
    background: rgba(13, 148, 136, 0.08);
}

.quiz-answer.revealed::before {
    opacity: 0;
    pointer-events: none;
}

/* ---------- Lesson Nav ---------- */
.lesson-nav {
    display: flex;
    justify-content: space-between;
    gap: var(--space-md);
    margin-top: var(--space-2xl);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--border);
}

.lesson-nav a {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    transition: all var(--transition);
}

.lesson-nav a:hover {
    border-color: var(--clr-tea);
    color: var(--clr-tea);
}

.lesson-nav .nav-label {
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-muted);
    display: block;
}

.lesson-nav .nav-title {
    display: block;
}

/* ---------- Responsive ---------- */
@media (max-width: 576px) {
    .lesson-pdf-block {
        flex-direction: column;
        align-items: flex-start;
    }

    .lesson-pdf-actions {
        width: 100%;
    }

    .lesson-pdf-btn {
        flex: 1;
        justify-content: center;
    }

    .lesson-nav {
        flex-direction: column;
    }

    .lesson-nav a {
        width: 100%;
    }

    .task-item {
        padding-left: calc(var(--space-md) + 36px);
    }
}