/* ============================================
   Lesson Page Specific Styles
   ============================================ */

/* Lesson Page Layout */
.lesson-page {
    background: var(--bg-primary);
}

.lesson-wrapper {
    display: flex;
    min-height: 100vh;
    padding-top: 0;
}

/* ============================================
   Sidebar Styles
   ============================================ */
.lesson-sidebar {
    width: 280px;
    min-width: 280px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    height: 100vh;
    position: sticky;
    top: 0;
    overflow-y: auto;
    transition: all var(--transition-base);
    z-index: 100;
}

.lesson-sidebar.collapsed {
    width: 60px;
    min-width: 60px;
}

.lesson-sidebar.collapsed .sidebar-logo .logo-text,
.lesson-sidebar.collapsed .sidebar-nav,
.lesson-sidebar.collapsed .sidebar-progress-title,
.lesson-sidebar.collapsed .sidebar-progress-text,
.lesson-sidebar.collapsed .sidebar-progress-bar {
    display: none;
}

.lesson-sidebar.collapsed .sidebar-logo {
    justify-content: center;
}

.lesson-sidebar.collapsed .sidebar-header {
    padding: 1rem 0.5rem;
}

/* Sidebar Header */
.sidebar-header {
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--glass-border);
}

.sidebar-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 1.1rem;
}

/* Sidebar Navigation */
.sidebar-nav {
    flex: 1;
    padding: 1rem 1.5rem;
    overflow-y: auto;
}

.sidebar-nav .nav-section-title {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--text-tertiary);
    margin: 1.5rem 0 0.75rem;
    font-weight: 700;
}

.sidebar-nav .nav-section-title:first-child {
    margin-top: 0;
}

.sidebar-nav a {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 0.75rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    transition: all var(--transition-fast);
    margin-bottom: 0.25rem;
}

.sidebar-nav a:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

.sidebar-nav a.active {
    background: rgba(19, 185, 253, 0.15);
    color: var(--accent-secondary);
    font-weight: 600;
}

.sidebar-nav a.completed {
    color: var(--accent-tertiary);
}

.sidebar-nav .nav-icon {
    font-size: 1rem;
    width: 24px;
    text-align: center;
    flex-shrink: 0;
}

.sidebar-nav .nav-check {
    margin-left: auto;
    font-size: 0.75rem;
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.sidebar-nav a.completed .nav-check {
    opacity: 1;
}

/* Sidebar Progress */
.sidebar-progress {
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--glass-border);
    border-bottom: 1px solid var(--glass-border);
}

.sidebar-progress-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-tertiary);
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.sidebar-progress-bar {
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.sidebar-progress-fill {
    height: 100%;
    background: var(--accent-gradient);
    border-radius: var(--radius-full);
    width: 0%;
    transition: width var(--transition-slow);
}

.sidebar-progress-text {
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

/* Sidebar Actions */
.sidebar-actions {
    padding: 0.75rem 1.5rem;
    display: flex;
    gap: 0.5rem;
}

.sidebar-btn {
    flex: 1;
    padding: 0.5rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.9rem;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.sidebar-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

/* ============================================
   Main Content Area
   ============================================ */
.lesson-main {
    flex: 1;
    overflow-y: auto;
    transition: all var(--transition-base);
}

.lesson-main.expanded {
    /* Adjust when sidebar is collapsed */
}

.lesson-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 3rem 2rem 4rem;
}

/* ============================================
   Lesson Header
   ============================================ */
.lesson-header {
    margin-bottom: 3rem;
}

.lesson-breadcrumb {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-tertiary);
    margin-bottom: 1rem;
}

.lesson-breadcrumb a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.lesson-breadcrumb a:hover {
    color: var(--accent-secondary);
}

.lesson-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 900;
    letter-spacing: -1px;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.lesson-emoji {
    display: inline-block;
    margin-right: 0.5rem;
}

.lesson-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.lesson-meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.meta-icon {
    font-size: 1.1rem;
}

.lesson-divider {
    margin-top: 1.5rem;
    height: 1px;
    background: var(--glass-border);
}

/* ============================================
   Lesson Sections
   ============================================ */
.lesson-section {
    margin-bottom: 4rem;
}

.section-heading {
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.heading-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--accent-gradient);
    border-radius: var(--radius-md);
    font-size: 1.25rem;
    flex-shrink: 0;
}

.section-description {
    color: var(--text-secondary);
    font-size: 1.05rem;
    line-height: 1.7;
    margin-bottom: 2rem;
    max-width: 700px;
}

/* ============================================
   Onboarding Wizard
   ============================================ */
.onboarding-wizard {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    overflow: hidden;
    padding: 2rem;
    margin-bottom: 4rem;
}

.wizard-steps {
    position: relative;
}

.wizard-step {
    display: none;
}

.wizard-step.active {
    display: block;
    animation: fadeSlideIn 0.4s ease;
}

@keyframes fadeSlideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.wizard-illustration {
    text-align: center;
    margin-bottom: 1.5rem;
}

.illustration-icon {
    font-size: 5rem;
    display: inline-block;
    animation: float 4s ease-in-out infinite;
}

.wizard-content h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.wizard-content p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1rem;
    font-size: 1.05rem;
}

.wizard-tools-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin: 1.5rem 0;
}

.wizard-tool-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    text-align: center;
    transition: all var(--transition-base);
}

.wizard-tool-card:hover {
    background: rgba(255, 255, 255, 0.06);
    transform: translateY(-2px);
}

.tool-icon {
    font-size: 2.5rem;
    display: block;
    margin-bottom: 0.75rem;
}

.wizard-tool-card h4 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.wizard-tool-card p {
    font-size: 0.85rem;
    color: var(--text-tertiary);
}

.wizard-navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--glass-border);
}

.wizard-btn {
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    border: none;
    transition: all var(--transition-base);
}

.next-btn {
    background: var(--accent-gradient);
    color: white;
    margin-left: auto;
}

.next-btn:hover {
    box-shadow: var(--shadow-glow-blue);
    transform: translateY(-1px);
}

.prev-btn {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--glass-border);
}

.prev-btn:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

/* ============================================
   OS Selector Tabs
   ============================================ */
.os-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 0;
    flex-wrap: wrap;
}

.os-tab {
    padding: 0.75rem 1.5rem;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    border-bottom: 3px solid transparent;
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.os-tab:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.03);
}

.os-tab.active {
    color: var(--accent-secondary);
    border-bottom-color: var(--accent-secondary);
}

.os-icon {
    font-size: 1.25rem;
}

.os-content {
    display: none;
}

.os-content.active {
    display: block;
    animation: fadeSlideIn 0.3s ease;
}

/* ============================================
   Instruction Blocks
   ============================================ */
.instruction-block {
    margin-bottom: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--glass-border);
}

.instruction-block:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.instruction-title {
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 1.25rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 80px;
    padding: 0.35rem 0.75rem;
    background: var(--accent-gradient);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 700;
    color: white;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.instruction-body {
    color: var(--text-secondary);
}

.instruction-body p {
    line-height: 1.7;
    margin-bottom: 1rem;
    font-size: 1rem;
}

.instruction-body strong {
    color: var(--text-primary);
}

.instruction-body code {
    font-family: var(--font-mono);
    background: rgba(19, 185, 253, 0.1);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--accent-secondary);
}

.instruction-action {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    margin: 1rem 0;
}

.instruction-action ol {
    padding-left: 1.5rem;
    margin-top: 0.5rem;
}

.instruction-action li {
    margin-bottom: 0.75rem;
    line-height: 1.6;
}

.instruction-action ul {
    padding-left: 1.5rem;
    margin: 0.5rem 0;
}

.instruction-action ul li {
    margin-bottom: 0.35rem;
}

/* ============================================
   Terminal Simulator
   ============================================ */
.terminal-simulator {
    background: #0D1117;
    border: 1px solid #30363D;
    border-radius: var(--radius-md);
    overflow: hidden;
    margin: 1.5rem 0;
    font-family: var(--font-mono);
}

.terminal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    background: #161B22;
    border-bottom: 1px solid #30363D;
}

.terminal-dots {
    display: flex;
    gap: 6px;
}

.terminal-dots .dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.terminal-dots .dot.red { background: #FF5F56; }
.terminal-dots .dot.yellow { background: #FFBD2E; }
.terminal-dots .dot.green { background: #27C93F; }

.terminal-title {
    font-size: 0.8rem;
    color: #8B949E;
}

.terminal-body {
    padding: 1.25rem;
    font-size: 0.9rem;
    line-height: 1.8;
}

.terminal-line {
    margin-bottom: 0.25rem;
}

.terminal-prompt {
    color: #27C93F;
    font-weight: 500;
}

.terminal-command {
    color: #E8EDF5;
}

.terminal-output {
    color: #8B949E;
    margin: 0.5rem 0;
    padding-left: 0.5rem;
    border-left: 2px solid #30363D;
}

.terminal-comment {
    color: #6E7681;
    font-style: italic;
}

/* ============================================
   Info Cards
   ============================================ */
.info-card {
    display: flex;
    gap: 1rem;
    padding: 1.25rem;
    border-radius: var(--radius-md);
    margin: 1.5rem 0;
    border: 1px solid;
}

.info-card.tip {
    background: rgba(19, 185, 253, 0.08);
    border-color: rgba(19, 185, 253, 0.2);
}

.info-card.important {
    background: rgba(255, 189, 46, 0.08);
    border-color: rgba(255, 189, 46, 0.2);
}

.info-card.warning {
    background: rgba(255, 95, 86, 0.08);
    border-color: rgba(255, 95, 86, 0.2);
}

.info-card.success {
    background: rgba(39, 201, 63, 0.08);
    border-color: rgba(39, 201, 63, 0.2);
}

.info-card.encouragement {
    background: rgba(0, 191, 166, 0.08);
    border-color: rgba(0, 191, 166, 0.2);
}

.info-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.info-content {
    line-height: 1.6;
}

.info-content strong {
    color: var(--text-primary);
}

.info-content ul {
    padding-left: 1.25rem;
    margin-top: 0.5rem;
}

.info-content li {
    margin-bottom: 0.25rem;
}

.external-link {
    color: var(--accent-secondary);
    text-decoration: none;
    border-bottom: 1px dashed var(--accent-secondary);
    transition: all var(--transition-fast);
}

.external-link:hover {
    border-bottom-style: solid;
}

/* ============================================
   Troubleshooting Grid
   ============================================ */
.troubleshooting-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.troubleshooting-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1.5rem;
}

.troubleshooting-card h4 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.troubleshooting-card p {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    line-height: 1.6;
}

.troubleshooting-card ul {
    padding-left: 1.25rem;
}

.troubleshooting-card li {
    color: var(--text-secondary);
    margin-bottom: 0.35rem;
    font-size: 0.9rem;
    line-height: 1.5;
}

.troubleshooting-card a {
    color: var(--accent-secondary);
}

.troubleshooting-card code {
    font-family: var(--font-mono);
    background: rgba(255, 255, 255, 0.05);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.85em;
}

/* ============================================
   Next Steps
   ============================================ */
.next-steps-content {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
}

.next-steps-content p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.next-steps-content ul {
    padding-left: 1.5rem;
    margin-bottom: 1.5rem;
}

.next-steps-content li {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.next-lesson-card {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.25rem;
    background: rgba(19, 185, 253, 0.08);
    border: 1px solid rgba(19, 185, 253, 0.2);
    border-radius: var(--radius-md);
    margin-top: 1rem;
}

.next-lesson-label {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 600;
}

.next-lesson-link {
    color: var(--accent-secondary);
    text-decoration: none;
    font-weight: 700;
    font-size: 1.1rem;
    transition: all var(--transition-fast);
}

.next-lesson-link:hover {
    text-decoration: underline;
}

/* ============================================
   Lesson Complete Card
   ============================================ */
.lesson-complete {
    margin-top: 4rem;
}

.complete-card {
    text-align: center;
    padding: 3rem 2rem;
    background: var(--bg-card);
    border: 2px solid var(--accent-tertiary);
    border-radius: var(--radius-xl);
    position: relative;
    overflow: hidden;
    transition: all var(--transition-base);
}

.complete-card.celebrated {
    animation: celebrate 0.6s ease;
}

@keyframes celebrate {
    0% { transform: scale(1); }
    50% { transform: scale(1.02); }
    100% { transform: scale(1); }
}

.complete-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(0, 191, 166, 0.05) 0%, transparent 100%);
    pointer-events: none;
}

.complete-icon {
    font-size: 4rem;
    display: block;
    margin-bottom: 1rem;
    animation: float 3s ease-in-out infinite;
}

.complete-card h2 {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 0.75rem;
}

.complete-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.complete-btn {
    font-size: 1.1rem;
    padding: 1rem 2.5rem;
    margin-bottom: 0.75rem;
}

.complete-btn.completed {
    background: var(--accent-tertiary);
    cursor: default;
    opacity: 0.8;
}

.complete-hint {
    font-size: 0.85rem;
    color: var(--text-tertiary);
}
/* ============================================
   Widget Tree Visual
   ============================================ */
.widget-tree-visual {
    background: rgba(6, 11, 24, 0.6);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin: 1.5rem 0;
    text-align: center;
}

.tree-node {
    padding: 0.75rem 1.25rem;
    margin: 0 auto;
    border-radius: var(--radius-md);
    background: rgba(14, 165, 233, 0.08);
    border: 1px solid rgba(14, 165, 233, 0.15);
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    min-width: 300px;
    transition: all var(--transition-base);
}

.tree-node:hover {
    background: rgba(14, 165, 233, 0.12);
    border-color: rgba(14, 165, 233, 0.3);
}

.tree-node.root {
    background: rgba(0, 196, 167, 0.12);
    border-color: rgba(0, 196, 167, 0.25);
    box-shadow: 0 0 15px rgba(0, 196, 167, 0.1);
}

.tree-node.child {
    background: rgba(196, 167, 0, 0.08);
    border-color: rgba(196, 167, 0, 0.2);
}

.node-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.node-label {
    font-family: var(--font-mono);
    font-weight: 700;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.node-desc {
    color: var(--text-tertiary);
    font-size: 0.8rem;
    margin-left: auto;
}

.tree-connector {
    color: var(--text-tertiary);
    font-size: 1.5rem;
    font-weight: bold;
    line-height: 1;
    text-align: center;
}

/* ============================================
   Code Explanation Blocks
   ============================================ */
.code-explanation-block {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--glass-border);
}

.code-explanation-block:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.code-explanation-block h4 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--accent-secondary);
    margin-bottom: 0.75rem;
}

.code-preview.inline-code {
    margin-bottom: 1rem;
}

.code-explanation {
    background: rgba(14, 165, 233, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
}

.code-explanation ul {
    padding-left: 1.25rem;
    margin-top: 0.5rem;
}

.code-explanation li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

.code-explanation code {
    font-family: var(--font-mono);
    background: rgba(14, 165, 233, 0.1);
    padding: 0.1rem 0.35rem;
    border-radius: 3px;
    font-size: 0.9em;
    color: var(--accent-secondary);
}

.highlight-change .code-body {
    position: relative;
}

.highlight-change .code-body::after {
    content: '✏️ Changed';
    position: absolute;
    top: 0.5rem;
    right: 0.75rem;
    background: rgba(255, 189, 46, 0.15);
    border: 1px solid rgba(255, 189, 46, 0.3);
    color: #FFBD2E;
    font-family: var(--font-sans);
    font-size: 0.7rem;
    padding: 0.2rem 0.5rem;
    border-radius: var(--radius-full);
    font-weight: 600;
}

.code-body .number {
    color: #F78C6C;
}

/* ============================================
   Review Grid
   ============================================ */
.review-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.review-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    transition: all var(--transition-base);
}

.review-card:hover {
    border-color: rgba(14, 165, 233, 0.25);
    box-shadow: var(--shadow-glow-blue);
    transform: translateY(-2px);
}

.review-icon {
    font-size: 1.5rem;
    display: block;
    margin-bottom: 0.5rem;
}

.review-card h4 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.review-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
}

.review-card code {
    font-family: var(--font-mono);
    background: rgba(14, 165, 233, 0.08);
    padding: 0.1rem 0.3rem;
    border-radius: 3px;
    font-size: 0.85em;
}

/* ============================================
   Quiz Game
   ============================================ */
.quiz-game {
    margin-top: 1rem;
}

.quiz-question {
    display: none;
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin-bottom: 1.5rem;
}

.quiz-question.active {
    display: block;
    animation: fadeSlideIn 0.4s ease;
}

.quiz-question-title {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
}

.quiz-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    background: var(--accent-gradient);
    border-radius: var(--radius-md);
    font-size: 0.85rem;
    font-weight: 800;
    color: white;
    flex-shrink: 0;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.quiz-option {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 0.95rem;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
    text-align: left;
    font-family: var(--font-sans);
}

.quiz-option:hover:not(.disabled) {
    background: rgba(14, 165, 233, 0.08);
    border-color: rgba(14, 165, 233, 0.25);
    color: var(--text-primary);
}

.quiz-option.disabled {
    cursor: default;
    opacity: 0.7;
}

.quiz-option.correct-answer {
    border-color: rgba(0, 196, 167, 0.5) !important;
    background: rgba(0, 196, 167, 0.1) !important;
    color: var(--accent-tertiary) !important;
    box-shadow: 0 0 15px rgba(0, 196, 167, 0.15);
}

.quiz-option.selected-correct {
    border-color: rgba(0, 196, 167, 0.5) !important;
    background: rgba(0, 196, 167, 0.1) !important;
    color: var(--accent-tertiary) !important;
}

.quiz-option.selected-wrong {
    border-color: rgba(255, 95, 86, 0.5) !important;
    background: rgba(255, 95, 86, 0.1) !important;
    color: #FF5F56 !important;
}

.option-letter {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.05);
    font-weight: 700;
    font-size: 0.85rem;
    flex-shrink: 0;
}

.quiz-feedback {
    display: none;
    margin-top: 1rem;
    padding: 1rem;
    border-radius: var(--radius-md);
}

.feedback-correct {
    color: var(--accent-tertiary);
    font-size: 0.95rem;
}

.feedback-wrong {
    color: #FF5F56;
    font-size: 0.95rem;
}

/* ============================================
   Project Cards
   ============================================ */
.project-section {
    margin-top: 3rem;
}

.project-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: 2rem;
    box-shadow: var(--shadow-md);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.25rem;
}

.project-badge {
    display: inline-block;
    padding: 0.4rem 1rem;
    background: var(--accent-gradient);
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 700;
    color: white;
}

.project-difficulty {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    background: rgba(255, 255, 255, 0.03);
    padding: 0.35rem 0.75rem;
    border-radius: var(--radius-full);
    border: 1px solid var(--glass-border);
}

.project-title {
    font-size: 1.5rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
}

.project-requirements,
.project-expected {
    margin-bottom: 1.5rem;
}

.project-requirements h4,
.project-expected h4 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.project-requirements ol,
.project-requirements ul {
    padding-left: 1.5rem;
}

.project-requirements li {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.project-requirements ul {
    margin-top: 0.5rem;
}

.project-requirements ul li {
    margin-bottom: 0.25rem;
}

/* ============================================
   Hidden Answer
   ============================================ */
.hidden-answer {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--glass-border);
}

.reveal-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: rgba(14, 165, 233, 0.1);
    border: 1px solid rgba(14, 165, 233, 0.2);
    border-radius: var(--radius-full);
    color: var(--accent-secondary);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all var(--transition-base);
    font-family: var(--font-sans);
}

.reveal-btn:hover {
    background: rgba(14, 165, 233, 0.2);
    border-color: rgba(14, 165, 233, 0.4);
    box-shadow: var(--shadow-glow-blue);
}

.answer-content {
    margin-top: 1.5rem;
    animation: fadeSlideIn 0.4s ease;
}

/* ============================================
   Responsive for Lesson 2
   ============================================ */
@media (max-width: 768px) {
    .widget-tree-visual {
        padding: 1rem;
    }
    
    .tree-node {
        min-width: auto;
        width: 100%;
        flex-wrap: wrap;
    }
    
    .review-grid {
        grid-template-columns: 1fr;
    }
    
    .project-card {
        padding: 1.5rem;
    }
    
    .project-title {
        font-size: 1.25rem;
    }
    
    .quiz-option {
        font-size: 0.85rem;
        padding: 0.75rem 1rem;
    }
}
/* ============================================
   Alignment Explanation Cards
   ============================================ */
.alignment-explanation {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.alignment-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
}

.alignment-card h4 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.alignment-card.main-axis {
    border-left: 4px solid var(--accent-secondary);
}

.alignment-card.cross-axis {
    border-left: 4px solid var(--accent-tertiary);
}

.alignment-card p {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    line-height: 1.5;
}

.alignment-card ul {
    padding-left: 1.25rem;
    margin-bottom: 1rem;
}

.alignment-card li {
    color: var(--text-secondary);
    margin-bottom: 0.35rem;
    font-size: 0.9rem;
}

.alignment-values {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.align-badge {
    display: inline-block;
    padding: 0.3rem 0.75rem;
    background: rgba(14, 165, 233, 0.1);
    border: 1px solid rgba(14, 165, 233, 0.2);
    border-radius: var(--radius-full);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--accent-secondary);
    font-weight: 500;
}

/* ============================================
   Grid Visual
   ============================================ */
.grid-visual {
    background: rgba(6, 11, 24, 0.6);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin: 1.5rem 0;
}

.grid-row {
    display: grid;
    grid-template-columns: 100px 1fr;
    border-bottom: 1px solid var(--glass-border);
}

.grid-row:last-child {
    border-bottom: none;
}

.grid-cell {
    padding: 0.75rem 1rem;
    font-size: 0.9rem;
}

.grid-cell.header {
    background: rgba(14, 165, 233, 0.1);
    font-weight: 700;
    color: var(--accent-secondary);
    font-size: 0.85rem;
}

.grid-cell.row-label {
    font-family: var(--font-mono);
    color: var(--text-tertiary);
    font-weight: 600;
    text-align: right;
}

.grid-cell:last-child {
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 0.85rem;
}

/* ============================================
   Alignment Demo Grid
   ============================================ */
.alignment-demo-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin: 1.5rem 0;
}

.alignment-demo-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
}

.alignment-demo-card h4 {
    font-size: 0.9rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    font-family: var(--font-mono);
}

.alignment-demo-card p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 0.75rem;
}

.demo-visual {
    display: flex;
    gap: 4px;
    background: rgba(255, 255, 255, 0.02);
    border: 1px dashed var(--glass-border);
    border-radius: var(--radius-sm);
    padding: 0.5rem;
    min-height: 40px;
}

.start-demo { justify-content: flex-start; }
.center-demo { justify-content: center; }
.end-demo { justify-content: flex-end; }
.evenly-demo { justify-content: space-evenly; }

.demo-block {
    font-size: 1.25rem;
    flex-shrink: 0;
}

/* ============================================
   Large Widget Tree Visual
   ============================================ */
.widget-tree-visual.large-tree {
    padding: 1.5rem;
}

.tree-children {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    padding: 0.5rem 0;
}

.tree-branch {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
}

/* ============================================
   Game Code Details (Collapsible)
   ============================================ */
.game-code-details {
    margin: 1rem 0;
}

.game-code-details summary {
    cursor: pointer;
    padding: 0.75rem 1rem;
    background: rgba(14, 165, 233, 0.08);
    border: 1px solid rgba(14, 165, 233, 0.2);
    border-radius: var(--radius-md);
    color: var(--accent-secondary);
    font-weight: 600;
    font-size: 0.95rem;
    transition: all var(--transition-fast);
}

.game-code-details summary:hover {
    background: rgba(14, 165, 233, 0.15);
}

.game-code-details .code-preview {
    margin-top: 0.5rem;
}

/* ============================================
   Responsive for Lesson 4
   ============================================ */
@media (max-width: 768px) {
    .alignment-explanation {
        grid-template-columns: 1fr;
    }
    
    .alignment-demo-grid {
        grid-template-columns: 1fr;
    }
    
    .tree-children {
        flex-direction: column;
        align-items: center;
    }
    
    .grid-visual .grid-row {
        grid-template-columns: 80px 1fr;
    }
}
/* ============================================
   DevTools Connection Visual
   ============================================ */
.devtools-connection-visual {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    padding: 2rem;
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    margin: 1.5rem 0;
}

.connection-step {
    display: flex;
    justify-content: center;
}

.connection-node {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.35rem;
    padding: 1.25rem 2rem;
    border-radius: var(--radius-lg);
    border: 2px solid;
    min-width: 200px;
}

.app-node {
    border-color: rgba(39, 201, 63, 0.4);
    background: rgba(39, 201, 63, 0.05);
}

.devtools-node {
    border-color: rgba(14, 165, 233, 0.4);
    background: rgba(14, 165, 233, 0.05);
}

.conn-icon {
    font-size: 2rem;
}

.conn-label {
    font-weight: 700;
    color: var(--text-primary);
    font-size: 1.1rem;
}

.conn-desc {
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

.connection-arrow {
    color: var(--accent-secondary);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    padding: 0.5rem 0;
}

/* ============================================
   Code Comparison Layout
   ============================================ */
.code-comparison {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1rem;
    align-items: start;
    margin: 1.5rem 0;
}

.comparison-panel h4 {
    font-size: 0.9rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.comparison-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 2rem;
    color: var(--accent-secondary);
    font-weight: 600;
    font-size: 0.9rem;
    white-space: nowrap;
}

/* DevTools Tree Mock */
.devtools-tree-mock {
    background: #0D1117;
    border: 1px solid #30363D;
    border-radius: var(--radius-md);
    padding: 1rem;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.8;
}

.dt-node {
    color: #8B949E;
}

.dt-node.indent-1 { padding-left: 1rem; }
.dt-node.indent-2 { padding-left: 2rem; }
.dt-node.indent-3 { padding-left: 3rem; }
.dt-node.indent-4 { padding-left: 4rem; }
.dt-node.indent-5 { padding-left: 5rem; }

/* ============================================
   Constraints Explanation
   ============================================ */
.constraints-explanation {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.constraint-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
}

.constraint-card h4 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.constraint-card p {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    font-size: 0.9rem;
}

.constraint-card.error-card {
    border-left: 4px solid #FF5F56;
}

.constraint-visual {
    display: flex;
    justify-content: center;
    padding: 1.5rem;
    border-radius: var(--radius-md);
    margin-bottom: 0.75rem;
}

.constraint-visual.normal {
    background: rgba(39, 201, 63, 0.05);
    border: 1px dashed rgba(39, 201, 63, 0.3);
}

.constraint-visual.unbounded {
    background: rgba(255, 95, 86, 0.05);
    border: 1px dashed rgba(255, 95, 86, 0.3);
}

.constraint-box {
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-family: var(--font-mono);
    border-radius: var(--radius-sm);
}

.constraint-box.fixed {
    width: 80px;
    height: 80px;
    background: rgba(39, 201, 63, 0.1);
    border: 2px solid rgba(39, 201, 63, 0.4);
    color: #27C93F;
    font-size: 0.85rem;
}

.constraint-box.infinite {
    width: 140px;
    height: 80px;
    background: rgba(255, 95, 86, 0.1);
    border: 2px solid rgba(255, 95, 86, 0.4);
    color: #FF5F56;
    font-size: 1.2rem;
}

.constraint-result {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    text-align: center;
}

/* ============================================
   Error Scenarios Grid
   ============================================ */
.error-scenarios {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin: 1.5rem 0;
}

.scenario-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-left: 4px solid #FF5F56;
    border-radius: var(--radius-md);
    padding: 1.25rem;
}

.scenario-card h4 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.scenario-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* ============================================
   Property Editor Mock
   ============================================ */
.property-editor-mock {
    background: #0D1117;
    border: 1px solid #30363D;
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin: 1.5rem 0;
}

.pe-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    background: #161B22;
    border-bottom: 1px solid #30363D;
}

.pe-title {
    font-weight: 700;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.pe-type {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    background: rgba(255, 255, 255, 0.05);
    padding: 0.2rem 0.5rem;
    border-radius: var(--radius-full);
}

.pe-properties {
    padding: 0.5rem;
}

.pe-property {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
}

.pe-property:hover {
    background: rgba(255, 255, 255, 0.03);
}

.pe-property.indent {
    padding-left: 2rem;
}

.pe-prop-name {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: #C792EA;
}

.pe-prop-value {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: #8B949E;
}

.pe-prop-value.editable {
    color: #FFBD2E;
    border-bottom: 1px dashed rgba(255, 189, 46, 0.3);
    cursor: pointer;
}

/* ============================================
   Experiment Grid
   ============================================ */
.experiment-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin: 1.5rem 0;
}

.experiment-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    transition: all var(--transition-fast);
}

.experiment-card:hover {
    border-color: rgba(14, 165, 233, 0.25);
    box-shadow: var(--shadow-glow-blue);
}

.experiment-card h4 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.experiment-card p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    line-height: 1.5;
}

.experiment-card code {
    font-family: var(--font-mono);
    background: rgba(14, 165, 233, 0.08);
    padding: 0.1rem 0.3rem;
    border-radius: 3px;
    font-size: 0.85em;
}

/* ============================================
   Responsive for Lesson 5
   ============================================ */
@media (max-width: 768px) {
    .constraints-explanation {
        grid-template-columns: 1fr;
    }
    
    .code-comparison {
        grid-template-columns: 1fr;
    }
    
    .comparison-arrow {
        transform: rotate(90deg);
        padding: 0.5rem 0;
    }
    
    .experiment-grid {
        grid-template-columns: 1fr;
    }
    
    .connection-node {
        min-width: 150px;
        padding: 1rem;
    }
}


/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
    .lesson-sidebar {
        width: 240px;
        min-width: 240px;
    }
    
    .lesson-content {
        padding: 2rem 1.5rem 3rem;
    }
    
    .wizard-tools-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .lesson-sidebar {
        position: fixed;
        left: -100%;
        width: 280px;
        min-width: 280px;
        z-index: 1000;
        transition: left var(--transition-base);
    }
    
    .lesson-sidebar.mobile-open {
        left: 0;
    }
    
    .lesson-sidebar.collapsed {
        width: 280px;
        min-width: 280px;
    }
    
    .lesson-main {
        width: 100%;
    }
    
    .lesson-content {
        padding: 1.5rem 1rem 3rem;
        max-width: 100%;
    }
    
    .lesson-title {
        font-size: 1.75rem;
    }
    
    .os-tabs {
        flex-direction: column;
        gap: 0.25rem;
    }
    
    .os-tab {
        border-bottom: none;
        border-left: 3px solid transparent;
        padding: 0.75rem 1rem;
    }
    
    .os-tab.active {
        border-bottom: none;
        border-left-color: var(--accent-secondary);
        background: rgba(19, 185, 253, 0.08);
    }
    
    .troubleshooting-grid {
        grid-template-columns: 1fr;
    }
    
    .lesson-meta {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .instruction-title {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
}

@media (max-width: 480px) {
    .wizard-step {
        padding: 0;
    }
    
    .terminal-body {
        font-size: 0.75rem;
        padding: 1rem;
        overflow-x: auto;
    }
    
    .complete-card {
        padding: 2rem 1rem;
    }
    
    .complete-card h2 {
        font-size: 1.5rem;
    }
}