/* Design System - Duolingo Style (Arabic Learning App) */
/* Following design-taste principles: clear hierarchy, good spacing, accessible */

:root {
    --bg: #fafbfc;
    --bg-alt: #ffffff;
    --text-primary: #1a1a1a;
    --text-secondary: #4b4b4b;
    --text-muted: #6b6b6b;
    --border: #e5e7eb;
    --accent: #58cc02; /* Duolingo green */
    --accent-hover: #4bb302;
    --accent-active: #3c9a02;
    --blue: #1cb0f6;
    --red: #ff4b4b;
    --orange: #ff9600;
    --purple: #ce82ff;
    --gold: #ffc800;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
    --shadow: 0 4px 16px rgba(0,0,0,0.08);
    --radius: 12px;
    --radius-lg: 16px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
}

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

html {
    font-size: 16px;
    line-height: 1.6;
}

body {
    font-family: 'Noto Sans Arabic', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    background: var(--bg);
    color: var(--text-primary);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-wrap: pretty;
}

.screen {
    display: none;
    min-height: 100vh;
    flex-direction: column;
}

.screen.active {
    display: flex;
}

/* Container */
.container {
    max-width: 680px;
    margin: 0 auto;
    padding: var(--spacing-md);
    width: 100%;
    flex: 1;
}

/* Onboarding */
.onboarding-hero {
    text-align: center;
    padding: var(--spacing-2xl) var(--spacing-md);
}

.app-logo {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.02em;
}

.hero-title {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    line-height: 1.15;
    text-wrap: balance;
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.125rem);
    color: var(--text-secondary);
    max-width: 520px;
    margin: 0 auto;
}

/* Sections */
.dialect-section {
    margin-top: var(--spacing-lg);
}

.section-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    text-align: center;
}

.dialect-grid {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.region-heading {
    font-size: 0.8125rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: var(--spacing-xs);
}

.dialect-grid-inner {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: var(--spacing-sm);
}

.dialect-card {
    background: var(--bg-alt);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: var(--spacing-md);
    text-align: center;
    cursor: pointer;
    transition: all 150ms ease-out;
    box-shadow: var(--shadow-sm);
    font-family: 'Noto Sans Arabic', sans-serif;
    display: flex;
    flex-direction: column;
    gap: 2px;
}

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

.dialect-card:focus-visible {
    outline: 3px solid var(--blue);
    outline-offset: 2px;
    border-color: var(--accent);
}

.dialect-card:active {
    transform: translateY(0) scale(0.97);
    transition: all 100ms ease-out;
}

.dialect-flag {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-xs);
    display: block;
}

.dialect-name-ar {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 2px;
}

.dialect-name-en {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Header */
.app-header {
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    padding: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    box-shadow: var(--shadow-sm);
}

.back-btn {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.5rem 0.875rem;
    font-size: 1rem;
    cursor: pointer;
    font-family: inherit;
    transition: all 120ms ease-out;
    min-width: 44px;
    min-height: 44px;
}

.back-btn:hover {
    background: var(--border);
}

.back-btn:focus-visible {
    outline: 3px solid var(--blue);
    outline-offset: 2px;
}

.back-btn:active {
    transform: scale(0.97);
}

.header-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 4px;
    min-width: 0;
}

.dialect-name {
    font-size: 1.125rem;
    font-weight: 700;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.streak-badge,
.xp-badge {
    font-size: 0.875rem;
    color: var(--text-secondary);
    background: var(--bg);
    padding: 4px 8px;
    border-radius: 6px;
    display: inline-block;
    width: fit-content;
}

.xp-badge {
    color: var(--orange);
    font-weight: 600;
}

/* Progress Overview */
.progress-overview {
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    box-shadow: var(--shadow-sm);
}

.progress-overview h3 {
    font-size: 1rem;
    margin-bottom: var(--spacing-sm);
    font-weight: 700;
}

.level-indicator {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.xp-bar {
    width: 100%;
    height: 10px;
    background: var(--border);
    border-radius: 5px;
    overflow: hidden;
}

.xp-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--gold), var(--orange));
    transition: width 300ms ease-out;
    border-radius: 5px;
}

/* Units */
.units-section h3 {
    font-size: 1rem;
    margin: var(--spacing-md) 0 var(--spacing-sm) 0;
    font-weight: 700;
}

.units-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.unit-card {
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    transition: all 150ms ease-out;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.unit-badge {
    flex: 0 0 auto;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    font-size: 1.1rem;
    background: var(--bg);
    border: 2px solid var(--border);
    color: var(--text-muted);
}

.unit-card:not(.locked):not(.completed) .unit-badge {
    border-color: var(--accent);
    color: var(--accent);
}

.unit-card.completed .unit-badge {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

.unit-card.locked .unit-badge {
    background: var(--bg);
}

.unit-body {
    flex: 1;
    min-width: 0;
}

.unit-card.locked {
    opacity: 0.6;
    cursor: not-allowed;
}

.unit-card:not(.locked) {
    cursor: pointer;
}

.unit-card:not(.locked):hover {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.unit-card:not(.locked):focus-visible {
    outline: 3px solid var(--blue);
    outline-offset: 2px;
}

.unit-card:not(.locked):active {
    transform: translateY(0) scale(0.98);
}

.unit-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xs);
}

.unit-title {
    font-size: 1.125rem;
    font-weight: 700;
}

.unit-status {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.unit-card:not(.locked) .unit-status {
    color: var(--accent);
    font-weight: 600;
}

.unit-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Bottom Nav */
.bottom-nav {
    background: var(--bg-alt);
    border-top: 1px solid var(--border);
    padding: var(--spacing-sm);
    display: flex;
    justify-content: space-around;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 20;
    box-shadow: 0 -2px 8px rgba(0,0,0,0.04);
}

.bottom-nav[hidden] {
    display: none;
}

body.has-nav {
    padding-bottom: 84px;
}

.nav-btn {
    background: transparent;
    border: none;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
    font-family: inherit;
    cursor: pointer;
    color: var(--text-muted);
    border-radius: 8px;
    min-height: 44px;
    min-width: 44px;
    transition: all 120ms ease-out;
}

.nav-btn:hover {
    background: var(--bg);
    color: var(--text-primary);
}

.nav-btn:focus-visible {
    outline: 3px solid var(--blue);
    outline-offset: 2px;
}

.nav-btn.active {
    color: var(--accent);
    font-weight: 600;
    background: rgba(88, 204, 2, 0.1);
}

/* Lesson Screen */
.lesson-header {
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    padding: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    box-shadow: var(--shadow-sm);
}

.close-lesson {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.5rem 0.875rem;
    font-size: 1rem;
    cursor: pointer;
    font-family: inherit;
    min-width: 44px;
    min-height: 44px;
    transition: all 120ms ease-out;
}

.close-lesson:hover {
    background: var(--border);
}

.close-lesson:focus-visible {
    outline: 3px solid var(--blue);
    outline-offset: 2px;
}

.close-lesson:active {
    transform: scale(0.97);
}

.lesson-progress {
    flex: 1;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.lesson-progress-bar {
    flex: 1;
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
}

.lesson-progress-fill {
    height: 100%;
    background: var(--accent);
    transition: width 250ms ease-out;
    border-radius: 4px;
}

.lesson-counter {
    font-size: 0.875rem;
    color: var(--text-muted);
    min-width: 60px;
    text-align: right;
}

.lesson-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    padding-top: var(--spacing-xl);
}

.question-area {
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    box-shadow: var(--shadow-sm);
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: var(--spacing-md);
}

.question-instruction {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: var(--spacing-xs);
}

.prompt-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.question-text {
    font-size: clamp(1.5rem, 5vw, 2.5rem);
    font-weight: 700;
    line-height: 1.3;
}

.question-hint {
    font-size: clamp(1rem, 3vw, 1.25rem);
    color: var(--text-secondary);
}

.speak-btn {
    flex: 0 0 auto;
    width: 52px;
    height: 52px;
    border-radius: 50%;
    border: 2px solid var(--blue);
    background: rgba(28, 176, 246, 0.1);
    color: var(--blue);
    font-size: 1.35rem;
    cursor: pointer;
    display: grid;
    place-items: center;
    transition: transform 120ms ease-out, background 120ms ease-out;
}

.speak-btn:hover {
    background: rgba(28, 176, 246, 0.2);
    transform: scale(1.05);
}

.speak-btn:focus-visible {
    outline: 3px solid var(--blue);
    outline-offset: 3px;
}

.speak-btn:active {
    transform: scale(0.94);
}

.choices {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

@media (max-width: 480px) {
    .choices {
        grid-template-columns: 1fr;
    }
}

.choice-btn {
    background: var(--bg-alt);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: var(--spacing-md);
    font-size: 1rem;
    font-family: 'Noto Sans Arabic', sans-serif;
    cursor: pointer;
    min-height: 56px;
    transition: all 150ms ease-out;
    box-shadow: var(--shadow-sm);
}

.choice-btn:hover:not(:disabled) {
    border-color: var(--accent);
    background: rgba(88, 204, 2, 0.05);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.choice-btn:focus-visible:not(:disabled) {
    outline: 3px solid var(--blue);
    outline-offset: 2px;
    border-color: var(--accent);
}

.choice-btn:active:not(:disabled) {
    transform: translateY(0) scale(0.97);
}

.choice-btn:disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

.choice-btn.correct {
    border-color: var(--accent);
    background: rgba(88, 204, 2, 0.1);
    color: var(--accent-hover);
    font-weight: 600;
}

.choice-btn.wrong {
    border-color: var(--red);
    background: rgba(255, 75, 75, 0.1);
    color: var(--red);
    font-weight: 600;
}

.choice-btn.selected {
    border-color: var(--blue);
    background: rgba(28, 176, 246, 0.1);
    box-shadow: 0 0 0 2px rgba(28, 176, 246, 0.35);
}

.choice-btn.correct,
.choice-btn.wrong {
    box-shadow: none;
}

/* Lesson complete panel */
.complete-panel {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
}

.complete-emoji {
    font-size: 3.5rem;
    line-height: 1;
}

.complete-title {
    font-size: 1.5rem;
    font-weight: 700;
}

.complete-stats {
    display: flex;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-sm);
}

.complete-stat {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.complete-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--accent);
}

.complete-label {
    font-size: 0.8125rem;
    color: var(--text-muted);
}

.feedback-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    min-height: 32px;
}

.feedback-text {
    text-align: center;
    font-size: 1.125rem;
    font-weight: 600;
    min-height: 28px;
}

.feedback-correct .feedback-text {
    color: var(--accent-hover);
}

.feedback-wrong .feedback-text {
    color: var(--red);
}

/* Auto-advance countdown: communicates when the next question arrives. */
.auto-timer {
    width: 100%;
    max-width: 320px;
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    overflow: hidden;
}

.auto-timer[hidden] {
    display: none;
}

.auto-timer-fill {
    width: 100%;
    height: 100%;
    background: var(--accent);
    transform: scaleX(0);
    transform-origin: right;
}

.auto-timer-fill.correct {
    background: var(--accent);
}

.auto-timer-fill.wrong {
    background: var(--red);
}

.complete-btn {
    margin-top: var(--spacing-lg);
    max-width: 320px;
    width: 100%;
}

.lesson-actions {
    background: var(--bg-alt);
    border-top: 1px solid var(--border);
    padding: var(--spacing-md);
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-end;
    position: sticky;
    bottom: 0;
    box-shadow: 0 -2px 8px rgba(0,0,0,0.04);
}

.lesson-actions .btn {
    flex: 0 0 auto;
    min-width: 120px;
    padding-inline: var(--spacing-xl);
}

.btn {
    flex: 1;
    padding: var(--spacing-md);
    font-size: 1rem;
    font-family: inherit;
    font-weight: 600;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    min-height: 56px;
    transition: all 150ms ease-out;
    box-shadow: var(--shadow-sm);
}

.btn:focus-visible {
    outline: 3px solid var(--blue);
    outline-offset: 2px;
}

.btn:active {
    transform: scale(0.97);
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--accent-hover);
    box-shadow: var(--shadow);
}

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

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

.btn-secondary:hover {
    background: var(--border);
    box-shadow: var(--shadow);
}

/* Profile */
.profile-card {
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    margin: var(--spacing-md) 0;
    box-shadow: var(--shadow-sm);
}

.profile-avatar {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.profile-name {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.profile-stats {
    display: flex;
    justify-content: space-around;
    gap: var(--spacing-md);
}

.stat {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--accent);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.achievements,
.settings {
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    box-shadow: var(--shadow-sm);
}

.achievements h3,
.settings h3 {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-md);
    font-weight: 700;
}

.badge-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--spacing-sm);
}

.badge-item {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--spacing-sm);
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.badge-item.locked {
    opacity: 0.5;
}

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

.badge-name {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.setting-item {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.setting-item label {
    font-weight: 600;
    font-size: 0.9rem;
}

.dialect-select {
    padding: var(--spacing-sm);
    font-size: 0.9rem;
    font-family: inherit;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-alt);
    min-height: 44px;
}

.install-row {
    margin-top: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.install-hint {
    font-size: 0.8125rem;
    color: var(--text-muted);
    margin-top: var(--spacing-xs);
}

/* Responsive */
@media (max-width: 640px) {
    .container {
        padding: var(--spacing-sm);
    }
    
    .onboarding-hero {
        padding: var(--spacing-xl) var(--spacing-sm);
    }
    
    .app-header {
        padding: var(--spacing-sm);
    }
    
    .lesson-header {
        padding: var(--spacing-sm);
    }
    
    .lesson-actions {
        padding: var(--spacing-sm);
    }
    
    .profile-stats {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .complete-stats {
        gap: var(--spacing-lg);
    }
}

/* Reduced motion: keep state-change clarity, drop the movement. */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }

    .dialect-card:hover,
    .unit-card:not(.locked):hover,
    .choice-btn:hover:not(:disabled),
    .speak-btn:hover {
        transform: none;
    }
}
/* Lesson title and transliteration hint */
.lesson-progress {
    flex-wrap: wrap;
}

.lesson-title {
    flex: 1 0 100%;
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--text-primary);
    order: -1;
}

.prompt-stack {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.prompt-translit {
    font-size: 0.9rem;
    color: var(--text-muted);
    letter-spacing: 0.02em;
    direction: ltr;
    text-align: right;
}

/* Test / review screen */
.test-card {
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
}

.test-lead {
    color: var(--text-secondary);
    line-height: 1.55;
    margin: 0 0 var(--spacing-lg);
}

.test-info {
    color: var(--text-muted);
    font-size: 0.875rem;
    line-height: 1.55;
    margin: var(--spacing-md) 0 var(--spacing-lg);
}

.test-card .btn {
    width: 100%;
}