/* 
 * Language Learning App - Main Stylesheet
 * Design System: Modern, minimal, high-contrast with glassmorphism effects
 */

/* ===== CSS Variables (Design Tokens) ===== */
:root {
    /* Color Palette - Light Theme */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-secondary: #7c3aed;
    --color-accent: #10b981;
    --color-danger: #ef4444;
    --color-warning: #f59e0b;
    
    /* Neutral Colors */
    --color-background: #ffffff;
    --color-surface: #f8fafc;
    --color-surface-2: #f1f5f9;
    --color-border: #e2e8f0;
    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-text-lighter: #94a3b8;
    
    /* Glassmorphism Effects */
    --glass-background: rgba(255, 255, 255, 0.9);
    --glass-border: rgba(255, 255, 255, 0.2);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-family: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Z-index layers */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-toast: 1070;
}

/* ===== Dark Theme Variables ===== */
.dark {
    --color-background: #0f172a;
    --color-surface: #1e293b;
    --color-surface-2: #334155;
    --color-border: #475569;
    --color-text: #f1f5f9;
    --color-text-light: #cbd5e1;
    --color-text-lighter: #94a3b8;
    
    /* Glassmorphism for Dark Theme */
    --glass-background: rgba(30, 41, 59, 0.9);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

/* ===== Base Styles ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
    transition: background-color var(--transition-base);
    min-height: 100vh;
    overflow-x: hidden;
}

/* Accessibility: Focus Styles */
:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Accessibility: Skip Link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    z-index: var(--z-popover);
    border-radius: var(--radius-sm);
}

.skip-link:focus {
    top: var(--spacing-sm);
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: var(--font-size-4xl);
}

h2 {
    font-size: var(--font-size-3xl);
}

h3 {
    font-size: var(--font-size-2xl);
}

h4 {
    font-size: var(--font-size-xl);
}

p {
    margin-bottom: var(--spacing-md);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
}

/* ===== Layout & Container ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ===== Header & Navigation ===== */
.header {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    background: var(--glass-background);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) 0;
}

.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo {
    font-size: 2rem;
    line-height: 1;
}

.site-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin: 0;
}

.main-nav {
    display: none;
}

.nav-list {
    display: flex;
    gap: var(--spacing-lg);
    list-style: none;
}

.nav-link {
    color: var(--color-text-light);
    font-weight: 500;
    padding: var(--spacing-sm) 0;
    position: relative;
}

.nav-link.active {
    color: var(--color-primary);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--color-primary);
    border-radius: var(--radius-full);
}

.user-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

/* Mobile Navigation */
.mobile-nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--color-surface);
    z-index: var(--z-modal);
    padding: var(--spacing-xl);
    transition: right var(--transition-base);
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.1);
}

.mobile-nav.active {
    right: 0;
}

.mobile-nav-list {
    list-style: none;
    margin-top: var(--spacing-2xl);
}

.mobile-nav-link {
    display: block;
    padding: var(--spacing-md) 0;
    color: var(--color-text);
    font-size: var(--font-size-lg);
    font-weight: 500;
    border-bottom: 1px solid var(--color-border);
}

.mobile-nav-link.active {
    color: var(--color-primary);
}

/* Overlay for mobile menu */
.mobile-nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: var(--z-modal-backdrop);
    display: none;
}

.mobile-nav-overlay.active {
    display: block;
}

/* ===== Settings Panel ===== */
.settings-panel {
    position: fixed;
    top: 0;
    right: -400px;
    width: 380px;
    height: 100vh;
    background: var(--color-surface);
    z-index: var(--z-modal);
    padding: 0;
    transition: right var(--transition-base);
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.1);
    overflow-y: auto;
}

.settings-panel.active {
    right: 0;
}

.settings-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.settings-content {
    padding: var(--spacing-lg);
}

.setting-group {
    margin-bottom: var(--spacing-xl);
}

.setting-group h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
    color: var(--color-text-light);
}

.setting-item {
    margin-bottom: var(--spacing-md);
}

/* ===== Main Content ===== */
.main-content {
    padding-bottom: var(--spacing-2xl);
}

/* Hero Section */
.hero {
    padding: var(--spacing-2xl) 0;
    text-align: center;
    background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-background) 100%);
    border-bottom: 1px solid var(--color-border);
}

.hero-title {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto var(--spacing-xl);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    flex-wrap: wrap;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.stat-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Sections */
.section {
    display: none;
    padding: var(--spacing-xl) 0;
    animation: fadeIn var(--transition-base);
}

.section.active-section {
    display: block;
}

.section-header {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

@media (min-width: 768px) {
    .section-header {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }
}

/* ===== Cards ===== */
.card {
    background: var(--glass-background);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--glass-shadow);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

/* ===== Translation Container ===== */
.translation-container {
    display: grid;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

@media (min-width: 992px) {
    .translation-container {
        grid-template-columns: 1fr 1fr;
    }
}

.input-card, .output-card {
    height: 100%;
    min-height: 500px;
    display: flex;
    flex-direction: column;
}

/* Input Area */
.text-input {
    width: 100%;
    min-height: 300px;
    padding: var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-background);
    color: var(--color-text);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    resize: vertical;
    transition: border-color var(--transition-fast);
}

.text-input:focus {
    border-color: var(--color-primary);
    outline: none;
}

.input-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: var(--spacing-md);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.char-count {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

.input-actions {
    display: flex;
    gap: var(--spacing-md);
}

/* Language Switcher */
.language-switcher {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.language-selector {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    min-width: 150px;
}

/* ===== Translation Output ===== */
.translated-text {
    min-height: 200px;
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    background: var(--color-surface-2);
    margin-bottom: var(--spacing-lg);
    font-size: var(--font-size-lg);
    line-height: 1.8;
}

.translated-text .word {
    cursor: pointer;
    padding: 2px 4px;
    border-radius: var(--radius-sm);
    transition: background-color var(--transition-fast);
}

.translated-text .word:hover {
    background-color: var(--color-surface);
}

.placeholder {
    color: var(--color-text-lighter);
    font-style: italic;
}

/* Translation Status */
.translation-status {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.status-indicator {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.status-indicator.idle {
    background-color: var(--color-text-lighter);
}

.status-indicator.loading {
    background-color: var(--color-warning);
    animation: pulse 1.5s infinite;
}

.status-indicator.success {
    background-color: var(--color-accent);
}

.status-indicator.error {
    background-color: var(--color-danger);
}

.status-text {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

/* Audio Controls */
.audio-controls {
    background: var(--color-surface-2);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.audio-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.voice-selector {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.audio-buttons {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.speed-control {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

/* Wave Animation */
.wave-animation {
    display: none;
    align-items: center;
    justify-content: center;
    gap: 4px;
    height: 40px;
    margin-top: var(--spacing-md);
}

.wave-animation.active {
    display: flex;
}

.wave-bar {
    width: 4px;
    height: 20px;
    background: var(--color-primary);
    border-radius: var(--radius-full);
    animation: wave 1.2s ease-in-out infinite;
}

.wave-bar:nth-child(2) { animation-delay: -1.1s; }
.wave-bar:nth-child(3) { animation-delay: -1.0s; }
.wave-bar:nth-child(4) { animation-delay: -0.9s; }
.wave-bar:nth-child(5) { animation-delay: -0.8s; }

/* Translation Details */
.translation-details {
    display: flex;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--color-surface-2);
    border-radius: var(--radius-md);
    flex-wrap: wrap;
}

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

.detail-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

.detail-value {
    font-weight: 500;
}

/* Output Actions */
.output-actions {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* ===== Word Details Panel ===== */
.word-details-panel {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.95);
    width: 90%;
    max-width: 500px;
    max-height: 80vh;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    z-index: var(--z-modal);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    overflow: hidden;
}

.word-details-panel.active {
    opacity: 1;
    visibility: visible;
    transform: translate(-50%, -50%) scale(1);
}

.panel-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.panel-body {
    padding: var(--spacing-lg);
    overflow-y: auto;
    max-height: calc(80vh - 73px);
}

/* Overlay for word details */
.word-details-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: calc(var(--z-modal) - 1);
    display: none;
}

.word-details-overlay.active {
    display: block;
}

/* ===== Flashcards & History ===== */
.flashcards-container,
.history-container,
.phrases-container {
    margin-top: var(--spacing-lg);
}

.flashcards-header,
.history-header {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 768px) {
    .flashcards-header,
    .history-header {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }
}

.flashcards-list,
.history-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.flashcard-item,
.history-item {
    background: var(--color-surface-2);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    border: 1px solid var(--color-border);
    transition: transform var(--transition-fast);
}

.flashcard-item:hover,
.history-item:hover {
    transform: translateX(4px);
}

.flashcard-content,
.history-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-md);
}

.flashcard-text,
.history-text {
    flex: 1;
}

.flashcard-source,
.history-source {
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
}

.flashcard-target,
.history-target {
    color: var(--color-text-light);
}

.flashcard-meta,
.history-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: var(--font-size-sm);
    color: var(--color-text-lighter);
    margin-top: var(--spacing-sm);
}

.flashcard-actions,
.history-actions {
    display: flex;
    gap: var(--spacing-sm);
}

/* ===== Phrases ===== */
.phrases-grid {
    display: grid;
    gap: var(--spacing-md);
}

@media (min-width: 640px) {
    .phrases-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 992px) {
    .phrases-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.phrase-card {
    background: var(--color-surface-2);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    border: 1px solid var(--color-border);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.phrase-card:hover {
    transform: translateY(-2px);
    border-color: var(--color-primary);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.1);
}

.phrase-text {
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
}

.phrase-translation {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    margin-bottom: var(--spacing-sm);
}

.phrase-category {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--color-surface);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    color: var(--color-text-light);
}

/* ===== Practice Modal ===== */
.practice-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: var(--z-modal);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.practice-modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.modal-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.modal-body {
    padding: var(--spacing-lg);
    overflow-y: auto;
    max-height: calc(90vh - 73px);
}

.practice-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.practice-stat {
    text-align: center;
    padding: var(--spacing-md);
    background: var(--color-surface-2);
    border-radius: var(--radius-md);
}

.practice-stat-label {
    display: block;
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xs);
}

.practice-stat-value {
    display: block;
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-primary);
}

.practice-card {
    background: var(--color-surface-2);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    border: 2px solid var(--color-border);
    text-align: center;
    min-height: 300px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.card-text {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-lg);
}

.card-hint {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    font-style: italic;
}

.card-feedback {
    margin-top: var(--spacing-xl);
}

.feedback-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.btn-feedback {
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.btn-feedback.hard {
    background: var(--color-warning);
    color: white;
}

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

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

.btn-feedback:hover {
    opacity: 0.9;
    transform: translateY(-2px);
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    white-space: nowrap;
}

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

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

.btn-secondary {
    background: var(--color-surface-2);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-surface);
    transform: translateY(-2px);
}

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

.btn-danger:hover {
    background: #dc2626;
    transform: translateY(-2px);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.icon-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--color-text);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.icon-btn:hover {
    background: var(--color-surface-2);
}

.icon-btn:active {
    transform: scale(0.95);
}

/* ===== Form Elements ===== */
.select-input {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-background);
    color: var(--color-text);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

.select-input:focus {
    border-color: var(--color-primary);
    outline: none;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    display: none;
}

.checkmark {
    width: 20px;
    height: 20px;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark {
    background: var(--color-primary);
    border-color: var(--color-primary);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark::after {
    content: '✓';
    color: white;
    font-size: 12px;
}



/* ===== Toast Notifications ===== */
.toast-container {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    max-width: 350px;
}

.toast {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    animation: slideInRight var(--transition-base);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.toast.success {
    border-left: 4px solid var(--color-accent);
}

.toast.error {
    border-left: 4px solid var(--color-danger);
}

.toast.warning {
    border-left: 4px solid var(--color-warning);
}

.toast.info {
    border-left: 4px solid var(--color-primary);
}

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

.toast.success .toast-icon {
    color: var(--color-accent);
}

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

.toast.warning .toast-icon {
    color: var(--color-warning);
}

.toast.info .toast-icon {
    color: var(--color-primary);
}

.toast-content {
    flex: 1;
}

.toast-title {
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
}

.toast-message {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

.toast-close {
    background: none;
    border: none;
    color: var(--color-text-light);
    cursor: pointer;
    padding: var(--spacing-xs);
}

/* ===== Empty States ===== */
.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--color-text-light);
    font-style: italic;
}

/* ===== Animations ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        transform: translate(-50%, 100%);
        opacity: 0;
    }
    to {
        transform: translate(-50%, 0);
        opacity: 1;
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

@keyframes wave {
    0%, 100% {
        height: 20px;
    }
    50% {
        height: 40px;
    }
}

/* ===== Responsive Design ===== */
@media (min-width: 768px) {
    .main-nav {
        display: block;
    }
    
    .mobile-menu-toggle {
        display: none;
    }
    
    .hero-title {
        font-size: var(--font-size-4xl);
    }
}

@media (max-width: 767px) {
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .hero-title {
        font-size: var(--font-size-2xl);
    }
    
    .hero-subtitle {
        font-size: var(--font-size-base);
    }
    
    .hero-stats {
        gap: var(--spacing-lg);
    }
    
    .stat-number {
        font-size: var(--font-size-2xl);
    }
    
    .input-actions {
        width: 100%;
        justify-content: stretch;
    }
    
    .input-actions .btn {
        flex: 1;
    }
    
    .output-actions {
        flex-direction: column;
    }
    
    .output-actions .btn {
        width: 100%;
    }
    
    .feedback-buttons {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ===== Reduced Motion Preference ===== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* ===== Print Styles ===== */
@media print {
    .header,
    .settings-panel,
    .offline-indicator,
    .toast-container,
    .icon-btn,
    button {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .card {
        border: 1px solid #ddd;
        box-shadow: none;
        break-inside: avoid;
    }
}



/* ===== Word Details Panel Enhancements ===== */
.word-meta {
  display: flex;
  gap: var(--spacing-sm);
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: var(--spacing-md);
}

.part-of-speech {
  background: var(--color-surface-2);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-style: italic;
  color: var(--color-text-light);
}

.source-badge {
  background: var(--color-primary);
  color: white;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: 500;
}

.pronunciation-section,
.definitions-section,
.examples-section,
.related-words-section {
  margin-bottom: var(--spacing-lg);
}

.pronunciation-section h4,
.definitions-section h4,
.examples-section h4,
.related-words-section h4 {
  font-size: var(--font-size-base);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-light);
}

.pronunciation {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.ipa {
  font-family: monospace;
  font-size: var(--font-size-lg);
  color: var(--color-primary);
}

.definitions-list {
  padding-left: var(--spacing-lg);
  margin: 0;
}

.definitions-list li {
  margin-bottom: var(--spacing-sm);
}

.examples-list {
  padding-left: var(--spacing-lg);
  margin: 0;
}

.examples-list li {
  margin-bottom: var(--spacing-sm);
  font-style: italic;
  color: var(--color-text-light);
}

.related-words-section > div {
  margin-bottom: var(--spacing-md);
}

.word-tag {
  display: inline-block;
  background: var(--color-surface-2);
  padding: 4px 8px;
  margin: 2px 4px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.word-tag:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-1px);
}

.license-notice {
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
  font-size: var(--font-size-xs);
  color: var(--color-text-light);
  text-align: center;
}

.fallback-notice {
  background: var(--color-warning);
  color: white;
  padding: var(--spacing-sm);
  border-radius: var(--radius-md);
  margin: var(--spacing-md) 0;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-sm);
}

.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-xl);
  color: var(--color-text-light);
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: var(--spacing-md);
}

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

.error-state {
  text-align: center;
  padding: var(--spacing-xl);
  color: var(--color-danger);
}

.error-state i {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
}