/* ============================
   Programming Learning App
   Modern Responsive CSS
   ============================ */

/* Force default cursor on EVERYTHING except explicit exceptions */
*:not(input):not(textarea):not(select):not(.ace_editor):not(.ace_editor *):not(a):not(button):not([onclick]):not([role="button"]) {
    cursor: default !important;
}
/* Interactive elements: pointer */
a, button, [onclick], [role="button"], select,
input[type="checkbox"], input[type="radio"],
.lesson-card:not(.locked), .hackathon-card:not(.locked), .badge-card,
.knowledge-map-header, .km-topic-header, .badge-buy-btn, .btn, .btn-back, .nav-item,
.settings-option, .lang-option, summary {
    cursor: pointer !important;
}
/* Text inputs: text cursor */
input[type="text"], input[type="password"], input[type="email"],
input[type="number"], input[type="search"], textarea {
    cursor: text !important;
}
/* Ace editor: text cursor */
.ace_editor, .ace_editor * {
    cursor: text !important;
}
/* Output: selectable text but default cursor */
.output-content, .output-content * {
    cursor: default !important;
    user-select: text;
}
/* Prevent text selection/caret everywhere except specific elements */
* {
    user-select: none;
    -webkit-user-select: none;
}
/* Allow text selection in editors, inputs, output, and code blocks */
input, textarea, select,
.ace_editor, .ace_editor *,
.output-content, .output-content *,
pre, pre *, code,
.km-desc, .km-code-example {
    user-select: text !important;
    -webkit-user-select: text !important;
}

/* CSS Custom Properties - Dark Theme (default) */
:root {
    --bg-primary: #0c0e14;
    --bg-secondary: #151823;
    --bg-card: #1c2033;
    --bg-hover: #252a40;
    --text-primary: #edf0f7;
    --text-secondary: #9ca3af;
    --text-muted: #6b7280;
    --accent: #6366f1;
    --accent-hover: #818cf8;
    --accent-light: rgba(99, 102, 241, 0.12);
    --accent-glow: rgba(99, 102, 241, 0.25);
    --success: #22c55e;
    --success-light: rgba(34, 197, 94, 0.12);
    --warning: #f59e0b;
    --warning-light: rgba(245, 158, 11, 0.12);
    --danger: #ef4444;
    --danger-light: rgba(239, 68, 68, 0.12);
    --border: #262d42;
    --border-light: #353d58;
    --radius: 14px;
    --radius-sm: 10px;
    --radius-xs: 6px;
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
    --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.2);
    --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.15);
    --font: 'Inter', 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', monospace;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: 0.15s ease;
    --nav-height: 64px;
    --nav-bg: rgba(12, 14, 20, 0.88);
    --nav-border: rgba(99, 102, 241, 0.08);
    --gradient-brand: linear-gradient(135deg, #6366f1, #a78bfa, #ec4899);
    --gradient-accent: linear-gradient(135deg, #6366f1, #818cf8);
}

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #f8f9fc;
    --bg-secondary: #ffffff;
    --bg-card: #ffffff;
    --bg-hover: #f3f4f8;
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --text-muted: #9ca3af;
    --accent: #6366f1;
    --accent-hover: #4f46e5;
    --accent-light: rgba(99, 102, 241, 0.08);
    --accent-glow: rgba(99, 102, 241, 0.15);
    --success: #16a34a;
    --success-light: rgba(22, 163, 74, 0.08);
    --warning: #d97706;
    --warning-light: rgba(217, 119, 6, 0.08);
    --danger: #dc2626;
    --danger-light: rgba(220, 38, 38, 0.08);
    --border: #e5e7eb;
    --border-light: #d1d5db;
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.06);
    --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.04);
    --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.06);
    --nav-bg: rgba(255, 255, 255, 0.88);
    --nav-border: rgba(0, 0, 0, 0.06);
}

/* Theme Toggle Button */
.theme-toggle {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    background: var(--bg-secondary);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    flex-shrink: 0;
    padding: 0;
}

.theme-toggle:hover {
    border-color: var(--accent);
    background: var(--accent-light);
    color: var(--accent);
}

.theme-toggle svg {
    width: 18px;
    height: 18px;
    stroke: currentColor;
    fill: none;
    stroke-width: 1.8;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* Dark mode (default): show sun icon to switch to light */
.theme-toggle .icon-sun { display: block; }
.theme-toggle .icon-moon { display: none; }
/* Light mode: show moon icon to switch to dark */
[data-theme="light"] .theme-toggle .icon-sun { display: none; }
[data-theme="light"] .theme-toggle .icon-moon { display: block; }

/* ===== RESET & BASE ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    padding-top: var(--nav-height);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* ===== NAVIGATION ===== */
#main-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background: var(--nav-bg);
    border-bottom: 1px solid var(--nav-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 28px;
    z-index: 1000;
    backdrop-filter: blur(24px) saturate(180%);
    -webkit-backdrop-filter: blur(24px) saturate(180%);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    transition: opacity var(--transition-fast);
}

.nav-brand:hover { opacity: 0.85; }

.nav-logo {
    font-size: 1.2rem;
    font-weight: 800;
    font-family: var(--font-mono);
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 4px;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    transition: all var(--transition);
    font-weight: 500;
    font-size: 0.9rem;
    letter-spacing: -0.01em;
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--accent-light);
}

.nav-link.active {
    color: var(--accent);
    background: var(--accent-light);
    font-weight: 600;
}

.nav-info {
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-points {
    background: var(--accent-light);
    color: var(--accent);
    padding: 6px 14px;
    border-radius: 20px;
    font-weight: 700;
    font-size: 0.85rem;
    letter-spacing: -0.01em;
}

.nav-lang {
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 700;
    font-size: 0.8rem;
    border: 1px solid var(--border);
    transition: all var(--transition);
    letter-spacing: 0.05em;
}

.nav-lang:hover {
    border-color: var(--accent);
    color: var(--accent);
}

/* ===== PAGES ===== */
.page {
    display: none;
    animation: fadeIn 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.page.active {
    display: block;
}

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

/* Container */
.container {
    max-width: 980px;
    margin: 0 auto;
    padding: 36px 28px;
}

/* ===== LOADING ===== */
.loading-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
    gap: 20px;
}

.spinner {
    width: 44px;
    height: 44px;
    border: 3px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
}

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

/* ===== WELCOME SCREEN ===== */
.welcome-container {
    text-align: center;
    max-width: 640px;
}

.welcome-title {
    font-size: 2.6rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
}

.welcome-icon {
    font-size: 2.8rem;
    font-weight: 800;
    font-family: var(--font-mono);
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 40px;
    line-height: 1.5;
}

.welcome-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    margin-bottom: 20px;
    box-shadow: var(--shadow-card);
}

.welcome-card h2 {
    margin-bottom: 20px;
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: -0.01em;
}

.lang-choice {
    display: flex;
    gap: 14px;
    justify-content: center;
    flex-wrap: wrap;
}

.choice-btn {
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 24px 20px;
    cursor: pointer;
    transition: all var(--transition);
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    min-width: 200px;
    flex: 1;
}

.choice-btn:hover {
    border-color: var(--accent);
    background: var(--accent-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 16px var(--accent-glow);
}

.choice-btn.active, .choice-btn.selected {
    border-color: var(--accent);
    background: var(--accent-light);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.choice-btn.small {
    padding: 14px 24px;
    min-width: 140px;
    flex-direction: row;
}

.choice-icon {
    font-size: 2.5rem;
}

.choice-label {
    font-size: 1.15rem;
    font-weight: 700;
}

.choice-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.4;
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    font-family: var(--font);
    font-size: 0.9rem;
    font-weight: 600;
    transition: all var(--transition);
    text-decoration: none;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    transform: none !important;
}

.btn-primary {
    background: var(--gradient-accent);
    color: white;
    box-shadow: 0 2px 8px var(--accent-glow);
}

.btn-primary:hover:not(:disabled) {
    box-shadow: 0 4px 16px var(--accent-glow);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--bg-card);
    border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--bg-hover);
    border-color: var(--border-light);
}

.btn-danger {
    background: var(--danger);
    color: white;
}

.btn-danger:hover:not(:disabled) {
    background: #dc2626;
    transform: translateY(-1px);
}

.btn-run {
    background: var(--success);
    color: white;
    font-weight: 700;
    box-shadow: 0 2px 8px rgba(34, 197, 94, 0.25);
}

.btn-run:hover:not(:disabled) {
    filter: brightness(1.1);
    transform: translateY(-1px);
}

.btn-reset {
    background: var(--bg-card);
    border: 1px solid var(--border);
}

.btn-reset:hover {
    background: var(--bg-hover);
}

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

.btn-skip:hover {
    border-color: var(--text-secondary);
    color: var(--text-primary);
}

.btn-back {
    background: transparent;
    color: var(--text-secondary);
    padding: 8px 0;
}

.btn-back:hover {
    color: var(--text-primary);
}

.btn-large {
    padding: 14px 40px;
    font-size: 1.05rem;
    margin-top: 20px;
    border-radius: var(--radius);
}

.run-icon {
    font-size: 0.75rem;
}

/* ===== INPUTS ===== */
.input {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font);
    font-size: 0.9rem;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.textarea {
    resize: vertical;
    min-height: 80px;
}

.select {
    padding: 10px 14px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font);
    font-size: 0.9rem;
    cursor: pointer;
    transition: border-color var(--transition);
}

.select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

/* ===== PROGRESS BAR ===== */
.assessment-progress {
    display: flex;
    align-items: center;
    gap: 16px;
    margin: 24px 0;
}

.progress-bar {
    flex: 1;
    height: 6px;
    background: var(--bg-card);
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-accent);
    border-radius: 3px;
    transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.progress-text {
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 500;
    white-space: nowrap;
}

/* ===== ASSESSMENT ===== */
.assessment-header {
    text-align: center;
    margin-bottom: 32px;
}

.assessment-header h1 {
    margin-bottom: 12px;
    font-weight: 800;
    letter-spacing: -0.02em;
}

.assessment-header p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.5;
}

.assessment-task {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow-card);
}

.task-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    gap: 12px;
}

.task-difficulty {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    text-transform: uppercase;
    flex-shrink: 0;
}

.task-difficulty.beginner { background: var(--success-light); color: var(--success); }
.task-difficulty.intermediate { background: var(--warning-light); color: var(--warning); }
.task-difficulty.advanced { background: var(--danger-light); color: var(--danger); }

/* ===== CODE EDITOR ===== */
.code-editor {
    width: 100%;
    height: 250px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    margin: 16px 0;
}

.editor-controls {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

/* ===== OUTPUT PANEL ===== */
.output-panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    margin-top: 16px;
}

.output-header {
    padding: 10px 16px;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.output-content {
    padding: 16px;
    font-family: var(--font-mono);
    font-size: 0.88rem;
    line-height: 1.6;
    min-height: 60px;
    max-height: 200px;
    overflow-y: auto;
    white-space: pre-wrap;
    word-break: break-word;
}

.output-content .error { color: var(--danger); }
.output-content .success { color: var(--success); }

/* ===== INPUT PROMPT (for input()/ReadLine) ===== */
.input-prompt-form {
    padding: 4px 0;
}
.input-prompt-title {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 12px;
}
.input-prompt-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 8px;
}
.input-prompt-row label {
    font-size: 0.82rem;
    color: var(--text-secondary);
    min-width: 80px;
    flex-shrink: 0;
}
.input-prompt-field {
    flex: 1;
    padding: 6px 10px;
    font-size: 0.85rem;
    font-family: var(--font-mono);
    background: var(--bg-primary);
    color: var(--text-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    outline: none;
    transition: border-color 0.2s;
}
.input-prompt-field:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.15);
}
.input-prompt-actions {
    margin-top: 12px;
    display: flex;
    gap: 8px;
}

/* ===== ASSESSMENT RESULTS ===== */
.assessment-results {
    text-align: center;
    padding: 48px 0;
}

.result-score {
    font-size: 4rem;
    font-weight: 800;
    margin: 20px 0;
    letter-spacing: -0.03em;
}

.result-score.good { color: var(--success); }
.result-score.medium { color: var(--warning); }
.result-score.low { color: var(--danger); }

.result-level {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
    font-weight: 500;
}

.result-start-lesson {
    font-size: 1rem;
    color: var(--accent);
    margin-bottom: 36px;
    font-weight: 600;
}

.profile-form {
    max-width: 400px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
    text-align: left;
}

.profile-form h3 {
    text-align: center;
    margin-bottom: 8px;
    font-weight: 700;
}

/* ===== HOME PAGE ===== */
.home-hero {
    text-align: center;
    padding: 48px 0 24px;
}

.home-logo {
    margin-bottom: 16px;
    line-height: 1;
}

.home-logo svg {
    filter: drop-shadow(0 4px 24px rgba(99, 102, 241, 0.3));
}

.home-title {
    font-size: 2.6rem;
    font-weight: 800;
    letter-spacing: -0.04em;
    margin-bottom: 8px;
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.home-subtitle {
    color: var(--accent-hover);
    font-size: 1.15rem;
    font-weight: 500;
    margin-bottom: 8px;
}

.home-desc {
    color: var(--text-secondary);
    font-size: 0.95rem;
    max-width: 520px;
    margin: 0 auto;
    line-height: 1.6;
}

.home-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
    margin: 36px 0;
}

.home-stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px 16px;
    text-align: center;
    box-shadow: var(--shadow-card);
    transition: all var(--transition);
}

.home-stat-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.home-stat-value {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--accent);
    letter-spacing: -0.02em;
}

.home-stat-label {
    font-size: 0.72rem;
    color: var(--text-muted);
    margin-top: 4px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.home-nav-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin: 28px 0;
}

.home-nav-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 20px;
    text-decoration: none;
    color: var(--text-primary);
    transition: all var(--transition);
    box-shadow: var(--shadow-card);
}

.home-nav-card:hover {
    border-color: var(--accent);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
    background: var(--accent-light);
}

.home-nav-icon {
    font-size: 2rem;
}

.home-nav-label {
    font-weight: 700;
    font-size: 1.05rem;
    letter-spacing: -0.01em;
}

.home-nav-desc {
    font-size: 0.82rem;
    color: var(--text-secondary);
    text-align: center;
    line-height: 1.4;
}

.home-actions {
    text-align: center;
    margin: 24px 0 8px;
}

.home-credits {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 40px;
    font-weight: 500;
}

/* ===== LESSONS GRID ===== */
.lessons-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 28px;
    flex-wrap: wrap;
    gap: 12px;
}

.lessons-greeting {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 8px;
    font-weight: 500;
}

.lessons-header h1 {
    font-weight: 800;
    letter-spacing: -0.02em;
}

.lessons-progress {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 500;
}

.lessons-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
}

.lesson-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-card);
}

.lesson-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-accent);
    opacity: 0;
    transition: opacity var(--transition);
}

.lesson-card:hover {
    border-color: var(--accent);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.lesson-card:hover::before {
    opacity: 1;
}

.lesson-card.locked {
    opacity: 0.45;
    cursor: not-allowed;
}

.lesson-card.locked:hover {
    border-color: var(--border);
    transform: none;
    box-shadow: var(--shadow-card);
}

.lesson-card.locked:hover::before {
    opacity: 0;
}

.lesson-card.completed {
    border-color: rgba(34, 197, 94, 0.3);
}

.lesson-card.completed::before {
    background: linear-gradient(90deg, var(--success), #4ade80);
    opacity: 1;
}

.lesson-card.completed::after {
    content: '\2713';
    position: absolute;
    top: 14px;
    right: 14px;
    width: 26px;
    height: 26px;
    background: var(--success);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
}

.lesson-card-number {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.lesson-card-title {
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 8px;
    letter-spacing: -0.01em;
}

.lesson-card-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 14px;
    line-height: 1.4;
}

.lesson-card-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.lesson-card-difficulty {
    display: flex;
    gap: 4px;
}

.diff-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--border);
    transition: background var(--transition);
}

.diff-dot.filled {
    background: var(--accent);
}

.lesson-card-score {
    font-weight: 700;
    font-size: 0.85rem;
}

.lesson-card-score.passed { color: var(--success); }
.lesson-card-score.failed { color: var(--danger); }

/* ===== SINGLE LESSON ===== */
.lesson-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
}

.lesson-number {
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 500;
}

.lesson-content {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
    line-height: 1.8;
    box-shadow: var(--shadow-card);
}

.lesson-content h1 {
    font-size: 2rem;
    margin-bottom: 8px;
    font-weight: 800;
    letter-spacing: -0.03em;
}

.lesson-content h2 {
    font-size: 1.4rem;
    margin-top: 36px;
    margin-bottom: 16px;
    color: var(--accent-hover);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.lesson-content h3 {
    font-size: 1.15rem;
    margin-top: 28px;
    margin-bottom: 12px;
    font-weight: 700;
}

.lesson-content p {
    margin-bottom: 16px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.lesson-content ul, .lesson-content ol {
    margin-bottom: 16px;
    padding-left: 24px;
}

.lesson-content li {
    margin-bottom: 8px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.lesson-content code {
    background: var(--bg-primary);
    padding: 2px 8px;
    border-radius: var(--radius-xs);
    font-family: var(--font-mono);
    font-size: 0.88em;
    color: var(--accent-hover);
    border: 1px solid var(--border);
    font-variant-ligatures: none;
    -webkit-font-variant-ligatures: none;
}

.lesson-content pre {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 20px;
    margin-bottom: 20px;
    overflow-x: auto;
}

.lesson-content pre code {
    background: none;
    padding: 0;
    font-size: 0.88rem;
    line-height: 1.7;
    border: none;
    font-variant-ligatures: none;
    -webkit-font-variant-ligatures: none;
}

.practice-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px 20px;
    margin: 32px 0 16px;
}
.practice-section h3 {
    margin: 0 0 8px;
    font-size: 1rem;
}
.practice-section p {
    margin: 4px 0;
    line-height: 1.6;
}
.practice-section code {
    background: var(--accent-light);
    padding: 2px 6px;
    border-radius: 3px;
    font-size: 0.85em;
}

.test-preview {
    background: linear-gradient(135deg, var(--bg-secondary), rgba(var(--primary-rgb, 99,102,241), 0.05));
    border-left: 4px solid var(--primary);
    border-radius: var(--radius-sm);
    padding: 16px 20px;
    margin: 24px 0 16px;
}
.test-preview h3 {
    margin: 0 0 8px;
    font-size: 1rem;
    color: var(--primary);
}
.test-preview p {
    margin: 4px 0;
    line-height: 1.6;
}

.lesson-footer {
    text-align: center;
    margin-top: 36px;
}

/* ===== KNOWLEDGE MAP ===== */
.knowledge-map {
    margin-top: 32px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
    background: var(--bg-card);
}
.knowledge-map-header {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 18px;
    cursor: pointer;
    user-select: none;
    background: linear-gradient(135deg, var(--bg-secondary), var(--bg-card));
    border-bottom: 1px solid var(--border);
    font-weight: 700;
    font-size: 0.95rem;
}
.knowledge-map-header:hover { background: var(--bg-hover); }
.knowledge-map-toggle {
    margin-left: auto;
    font-size: 0.75rem;
    color: var(--text-muted);
    transition: transform 0.3s;
}
.knowledge-map-body {
    display: none;
    padding: 16px;
}
.knowledge-map-body.open {
    display: block;
}
.km-topic {
    margin-bottom: 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: var(--bg-primary);
    transition: box-shadow 0.2s;
}
.km-topic:hover {
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.12);
}
.km-topic:last-child { margin-bottom: 0; }
.km-topic-header {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    cursor: pointer;
    user-select: none;
    font-weight: 600;
    font-size: 0.88rem;
    color: var(--text-primary);
    background: var(--bg-secondary);
    border-bottom: 1px solid transparent;
    transition: background 0.2s;
}
.km-topic-header:hover { background: var(--bg-hover); }
.km-topic-header .km-icon {
    font-size: 1.1rem;
    flex-shrink: 0;
}
.km-topic-header .km-arrow {
    margin-left: auto;
    font-size: 0.65rem;
    color: var(--text-muted);
    transition: transform 0.3s;
}
.km-topic.open .km-arrow {
    transform: rotate(180deg);
}
.km-topic.open .km-topic-header {
    border-bottom-color: var(--border);
}
.km-topic-body {
    display: none;
    padding: 12px 14px;
}
.km-topic.open .km-topic-body {
    display: block;
}
.km-section {
    margin-bottom: 10px;
}
.km-section:last-child { margin-bottom: 0; }
.km-section-title {
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}
.km-items {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}
.km-chip {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 10px;
    font-size: 0.78rem;
    border-radius: 20px;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border: 1px solid var(--border);
    transition: all 0.2s;
}
.km-chip:hover {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}
.km-chip.km-chip-tip {
    background: rgba(245, 158, 11, 0.1);
    border-color: rgba(245, 158, 11, 0.3);
    color: #b45309;
}
[data-theme="dark"] .km-chip.km-chip-tip {
    background: rgba(245, 158, 11, 0.15);
    color: #fbbf24;
}
.km-chip.km-chip-tip:hover {
    background: #f59e0b;
    color: #fff;
    border-color: #f59e0b;
}
.km-desc {
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 8px;
}
.km-code-example {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 8px 12px;
    margin-top: 6px;
    font-size: 0.78rem;
    font-family: 'Fira Code', 'Consolas', monospace;
    overflow-x: auto;
    white-space: pre;
    color: var(--text-primary);
}

/* ===== TEST SCREEN ===== */
.test-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
}

.test-header h1 {
    flex: 1;
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.test-description {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px;
    margin-bottom: 20px;
    color: var(--text-secondary);
    line-height: 1.7;
    box-shadow: var(--shadow-card);
}

.test-description code {
    background: var(--bg-primary);
    padding: 2px 6px;
    border-radius: var(--radius-xs);
    font-family: var(--font-mono);
    color: var(--accent-hover);
    border: 1px solid var(--border);
}

/* Test Results */
.test-results {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px;
    margin-top: 24px;
    text-align: center;
    box-shadow: var(--shadow-card);
}

.test-score {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 12px;
    letter-spacing: -0.03em;
}

.test-score.passed { color: var(--success); }
.test-score.failed { color: var(--danger); }

.test-feedback {
    color: var(--text-secondary);
    margin-bottom: 24px;
    font-size: 1.05rem;
}

.test-actions {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
}

/* ===== BADGES ===== */
.badges-info {
    display: flex;
    gap: 14px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.badges-points, .badges-owned {
    background: var(--bg-card);
    padding: 12px 20px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    font-weight: 600;
    font-size: 0.9rem;
    box-shadow: var(--shadow-card);
}

.badges-filter {
    display: flex;
    gap: 8px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 7px 16px;
    border-radius: 20px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-secondary);
    cursor: pointer;
    font-family: var(--font);
    font-size: 0.82rem;
    font-weight: 600;
    transition: all var(--transition);
}

.filter-btn:hover, .filter-btn.active {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-light);
}

.badges-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 14px;
}

.badge-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px 16px;
    text-align: center;
    transition: all var(--transition);
    box-shadow: var(--shadow-card);
}

.badge-card:hover {
    border-color: var(--accent);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.badge-card.owned {
    border-color: rgba(34, 197, 94, 0.4);
    background: var(--success-light);
}

.badge-card.affordable {
    border-color: rgba(99, 102, 241, 0.4);
}

.badge-icon {
    font-size: 2.4rem;
    margin-bottom: 10px;
    display: block;
}

.badge-name {
    font-weight: 700;
    font-size: 0.95rem;
    margin-bottom: 6px;
    letter-spacing: -0.01em;
}

.badge-desc {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
    line-height: 1.4;
}

.badge-price {
    font-weight: 700;
    font-size: 0.85rem;
    color: var(--accent);
    margin-bottom: 12px;
}

.badge-card.owned .badge-price {
    color: var(--success);
}

.badge-buy-btn {
    padding: 8px 22px;
    border-radius: 20px;
    border: none;
    background: var(--gradient-accent);
    color: white;
    cursor: pointer;
    font-family: var(--font);
    font-weight: 600;
    font-size: 0.82rem;
    transition: all var(--transition);
}

.badge-buy-btn:hover {
    box-shadow: 0 4px 12px var(--accent-glow);
    transform: translateY(-1px);
}

.badge-buy-btn:disabled {
    background: var(--border);
    cursor: not-allowed;
    color: var(--text-muted);
    box-shadow: none;
    transform: none;
}

.badge-owned-label {
    color: var(--success);
    font-weight: 700;
    font-size: 0.85rem;
}
.badge-locked-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-style: italic;
    padding: 4px 0;
}
.badge-card.locked {
    opacity: 0.6;
}

/* ===== SETTINGS ===== */
.settings-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    margin-bottom: 20px;
    box-shadow: var(--shadow-card);
}

.settings-section h2 {
    margin-bottom: 20px;
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: -0.01em;
}

.settings-danger {
    border-color: rgba(239, 68, 68, 0.3);
}

.setting-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 0;
    border-bottom: 1px solid var(--border);
    gap: 16px;
}

.setting-row:last-of-type {
    border-bottom: none;
}

.setting-row label:first-child {
    font-weight: 600;
    white-space: nowrap;
    font-size: 0.9rem;
}

.setting-row .input, .setting-row .textarea {
    max-width: 400px;
}

.setting-row .select {
    min-width: 180px;
}

/* Toggle Switch */
.toggle {
    position: relative;
    display: inline-block;
    width: 48px;
    height: 26px;
}

.toggle input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--border);
    border-radius: 13px;
    transition: var(--transition);
}

.toggle-slider::before {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    left: 3px;
    bottom: 3px;
    background: white;
    border-radius: 50%;
    transition: var(--transition);
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

.toggle input:checked + .toggle-slider {
    background: var(--accent);
}

.toggle input:checked + .toggle-slider::before {
    transform: translateX(22px);
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 12px;
}

.stat-item {
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    padding: 18px;
    text-align: center;
    border: 1px solid var(--border);
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--accent);
    letter-spacing: -0.02em;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 4px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

/* Dashboard Chart */
.dashboard-empty {
    color: var(--text-muted);
    font-style: italic;
    text-align: center;
    padding: 20px;
}
.chart-container {
    display: flex;
    align-items: flex-end;
    gap: 4px;
    height: 200px;
    padding: 8px 24px 8px 0;
    border-bottom: 2px solid var(--border);
    position: relative;
}
.chart-ref-line {
    position: absolute;
    left: 0;
    right: 0;
    border-top: 1px dashed var(--text-muted);
    opacity: 0.3;
    pointer-events: none;
    z-index: 1;
}
.chart-ref-pass {
    border-top-color: var(--warning);
    opacity: 0.5;
}
.chart-ref-label {
    position: absolute;
    right: -22px;
    top: -8px;
    font-size: 0.55rem;
    color: var(--text-muted);
}
.chart-avg-line {
    position: absolute;
    left: 0;
    right: 0;
    border-top: 2px solid var(--primary);
    opacity: 0.6;
    pointer-events: none;
    z-index: 1;
}
.chart-avg-label {
    position: absolute;
    right: -22px;
    top: -8px;
    font-size: 0.55rem;
    color: var(--primary);
    font-weight: 700;
}
.chart-bar-wrapper {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    height: 100%;
    justify-content: flex-end;
    min-width: 0;
    z-index: 2;
}
.chart-bar-value {
    font-size: 0.6rem;
    font-weight: 700;
    color: var(--text-muted);
    margin-bottom: 2px;
}
.chart-bar {
    width: 100%;
    max-width: 28px;
    min-height: 4px;
    border-radius: 3px 3px 0 0;
    transition: height 0.4s ease-out, transform 0.2s;
    background-image: linear-gradient(to top, rgba(0,0,0,0.15), transparent) !important;
    background-blend-mode: overlay;
    box-shadow: 0 -1px 3px rgba(0,0,0,0.1);
}
.chart-bar-wrapper:hover .chart-bar {
    transform: scaleX(1.2);
    filter: brightness(1.15);
}
.chart-bar-wrapper:hover .chart-bar-value {
    color: var(--text-primary);
}
.chart-bar-label {
    font-size: 0.65rem;
    color: var(--text-muted);
    margin-top: 4px;
}
.chart-legend {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-top: 8px;
    font-size: 0.75rem;
    color: var(--text-muted);
}
.chart-legend-item {
    display: inline-flex;
    align-items: center;
    gap: 4px;
}
.dashboard-stats-row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-top: 16px;
}
.dashboard-stat {
    text-align: center;
    padding: 12px 8px;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
}
.dashboard-stat-value {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--accent);
    display: block;
}
.dashboard-stat-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.03em;
    margin-top: 2px;
}
.dashboard-suggestion {
    margin-top: 16px;
    padding: 12px 16px;
    background: rgba(239, 68, 68, 0.08);
    border-left: 3px solid var(--danger);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    font-size: 0.85rem;
    line-height: 1.6;
}
.dashboard-link {
    color: var(--primary);
    text-decoration: underline;
}
.dashboard-link:hover {
    color: var(--accent);
}

/* Settings badges display */
.badges-display {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.badge-mini {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-secondary);
    padding: 8px 14px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    border: 1px solid var(--border);
}

.badge-mini-icon {
    font-size: 1.1rem;
}

.no-badges {
    color: var(--text-muted);
    font-style: italic;
    font-size: 0.9rem;
}

/* ===== UTILITIES ===== */
.hidden {
    display: none !important;
}

/* Toast notification */
.toast {
    position: fixed;
    bottom: 28px;
    right: 28px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 24px;
    z-index: 2000;
    animation: slideUp 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow);
    max-width: 350px;
    font-weight: 500;
    font-size: 0.9rem;
}

.toast.success { border-color: var(--success); color: var(--success); }
.toast.error { border-color: var(--danger); color: var(--danger); }

@keyframes slideUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--border-light);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ===== HACKATHONS ===== */
.hackathons-subtitle {
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.hackathons-actions {
    margin-bottom: 32px;
}

.hackathons-section {
    margin-top: 32px;
}

.hackathons-section h2 {
    margin-bottom: 16px;
    font-size: 1.15rem;
}

.hackathons-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 16px;
}

.hackathon-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.hackathon-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, #f59e0b, #ef4444, #ec4899);
}

.hackathon-card:hover {
    border-color: #f59e0b;
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.hackathon-card.completed::before {
    background: linear-gradient(90deg, var(--success), #4ade80);
}

.hackathon-card h3 {
    font-size: 0.95rem;
    margin-top: 8px;
}

.hackathon-icon {
    font-size: 1.5rem;
}

.hackathon-score-badge {
    display: inline-block;
    margin-top: 8px;
    padding: 2px 8px;
    border-radius: 10px;
    font-size: 0.8rem;
    font-weight: 700;
    background: var(--accent-light);
    color: var(--accent);
}

.active-hackathon {
    border-color: #f59e0b;
    background: var(--bg-card);
}

.active-hackathon p {
    color: var(--text-secondary);
    margin: 8px 0 12px;
    font-size: 0.9rem;
}

.hackathon-history-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border);
}

.hackathon-history-title {
    flex: 1;
    font-weight: 600;
}

.hackathon-history-score {
    font-weight: 700;
    color: var(--accent);
}

.hackathon-history-date {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.no-hackathons {
    color: var(--text-muted);
    font-style: italic;
}

/* Hackathon detail page */
.hackathon-nav {
    margin-bottom: 20px;
}

.hackathon-challenge h1 {
    margin-bottom: 16px;
}

.hackathon-desc {
    margin-bottom: 24px;
    line-height: 1.7;
    color: var(--text-secondary);
}

.hackathon-desc ul {
    padding-left: 20px;
    margin: 10px 0;
}

.hackathon-desc li {
    margin-bottom: 4px;
}

.hackathon-results {
    margin-top: 24px;
    text-align: center;
}

.hackathon-score {
    margin-bottom: 16px;
}

.hackathon-feedback {
    margin-bottom: 16px;
}


.points-earned {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--success);
    margin-top: 8px;
}

/* Lesson card hackathon indicator */
.lesson-card.hackathon {
    position: relative;
}

.lesson-card.hackathon::before {
    background: linear-gradient(90deg, #f59e0b, #ef4444, #ec4899) !important;
    opacity: 1 !important;
}

.lesson-card-hackathon-badge {
    position: absolute;
    top: 14px;
    right: 14px;
    font-size: 1.2rem;
}

/* ===== HISTORY PAGE ===== */
.history-subtitle {
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.history-section {
    margin-bottom: 32px;
}

.history-section h2 {
    font-size: 1.2rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.history-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 18px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text-primary);
    transition: all var(--transition);
    cursor: pointer;
}

.history-item:hover {
    background: var(--bg-hover);
    border-color: var(--accent);
    transform: translateX(4px);
}

.history-item-icon {
    font-size: 1.2rem;
    flex-shrink: 0;
}

.history-item-title {
    flex: 1;
    font-weight: 500;
    font-size: 0.9rem;
}

.history-item-score {
    font-weight: 700;
    font-size: 0.85rem;
    padding: 2px 10px;
    border-radius: var(--radius-xs);
    background: var(--accent-light);
    color: var(--accent);
}

.history-item-score.passed {
    background: var(--success-light);
    color: var(--success);
}

.history-item-score.failed {
    background: var(--danger-light);
    color: var(--danger);
}

.history-item-date {
    font-size: 0.8rem;
    color: var(--text-muted);
    flex-shrink: 0;
}

.history-empty {
    color: var(--text-muted);
    font-style: italic;
}

/* ===== HELP PAGE ===== */

.help-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 16px;
}

.help-section h2 {
    font-size: 1.15rem;
    margin-bottom: 10px;
    color: var(--accent);
}

.help-section p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 8px;
}

.help-section p:last-child {
    margin-bottom: 0;
}

.help-section ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.help-section ul li {
    color: var(--text-secondary);
    line-height: 1.7;
    padding: 4px 0 4px 20px;
    position: relative;
}

.help-section ul li::before {
    content: '\2022';
    color: var(--accent);
    font-weight: bold;
    position: absolute;
    left: 0;
}

/* Locked hackathon card in hackathons section */
.hackathon-card.locked {
    opacity: 0.5;
    cursor: not-allowed;
}

.hackathon-card.locked:hover {
    transform: none;
    border-color: var(--border);
}

.hackathon-locked-text {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
    margin: 4px 0 0;
}

/* ===== MOBILE BOTTOM NAV ===== */
#mobile-nav {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: auto;
    background: var(--nav-bg);
    border-top: 1px solid var(--nav-border);
    backdrop-filter: blur(24px) saturate(180%);
    -webkit-backdrop-filter: blur(24px) saturate(180%);
    z-index: 1000;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    padding: 4px 4px;
}

.mobile-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1px;
    text-decoration: none;
    color: var(--text-muted);
    font-size: 0.6rem;
    font-weight: 600;
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    min-width: 48px;
}

.mobile-nav-item:hover, .mobile-nav-item.active {
    color: var(--accent);
    background: var(--accent-light);
}

.mobile-nav-icon {
    font-size: 1.2rem;
    line-height: 1;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
    :root {
        --nav-height: 56px;
    }

    body {
        padding-bottom: 80px;
    }

    #main-nav {
        padding: 0 14px;
    }

    .nav-links {
        display: none;
    }

    #mobile-nav {
        display: flex;
    }

    .home-nav-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .nav-brand span:not(.nav-logo) {
        display: none;
    }

    .container {
        padding: 20px 16px;
    }

    .welcome-title {
        font-size: 1.8rem;
    }

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

    .choice-btn {
        min-width: 140px;
        padding: 18px;
    }

    .home-title {
        font-size: 2rem;
    }

    .home-stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .home-nav-grid {
        grid-template-columns: 1fr;
    }

    .lessons-grid {
        grid-template-columns: 1fr;
    }

    .badges-grid {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    }

    .lesson-content {
        padding: 22px;
    }

    .setting-row {
        flex-direction: column;
        align-items: flex-start;
    }

    .setting-row .input, .setting-row .textarea, .setting-row .select {
        max-width: 100%;
        width: 100%;
    }

    .test-score {
        font-size: 2.5rem;
    }

    .result-score {
        font-size: 3rem;
    }

    .dashboard-stats-row {
        grid-template-columns: repeat(2, 1fr);
    }

}

@media (max-width: 480px) {
    .welcome-title {
        font-size: 1.4rem;
        flex-direction: column;
        gap: 8px;
    }

    .lang-choice {
        flex-direction: column;
    }

    .editor-controls {
        flex-direction: column;
    }

    .editor-controls .btn {
        width: 100%;
        justify-content: center;
    }

    .nav-info {
        gap: 6px;
    }

    .nav-points {
        font-size: 0.8rem;
        padding: 5px 10px;
    }
}