:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --bg-color: #f9fafb;
    --card-bg: #ffffff;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
}

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

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

.app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navbar */
.navbar {
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Main Content */
.main-content {
    flex: 1;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    padding: 2rem 1rem;
}

/* Dashboard */
.dashboard {
    text-align: center;
}

.dashboard h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.subtitle {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin: 2rem 0;
}

.stat-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.stat-card.stat-due {
    border-color: var(--primary-color);
    border-width: 2px;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.stat-label {
    color: var(--text-secondary);
    margin-top: 0.5rem;
    font-size: 0.875rem;
}

.action-section {
    margin-top: 2rem;
}

.start-review-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 1rem 2rem;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
}

.start-review-btn:hover {
    background-color: var(--primary-hover);
}

.no-cards {
    font-size: 1.25rem;
    color: var(--text-secondary);
}

/* Review Container */
.review-container {
    max-width: 600px;
    margin: 0 auto;
}

.progress-bar {
    background-color: var(--card-bg);
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 2rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.progress-text {
    text-align: center;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.progress-fill {
    height: 8px;
    background-color: var(--primary-color);
    border-radius: 4px;
    transition: width 0.3s ease;
}

.card-display {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    min-height: 400px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.card-front {
    text-align: center;
    padding: 2rem 0;
}

.card-text {
    font-size: 2.5rem;
    font-weight: bold;
    margin-bottom: 1rem;
}

/* Part of speech indicator displayed after the word */
.pos-indicator-wrapper {
    position: relative;
    display: inline;
}

.pos-indicator {
    font-size: 0.6em;
    font-weight: normal;
    color: var(--text-secondary);
    cursor: pointer;
    text-decoration: underline dotted;
    text-underline-offset: 2px;
}

.pos-indicator:hover {
    color: var(--primary-color);
}

/* Tooltip shown on click (mobile-friendly) */
.pos-tooltip {
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    white-space: nowrap;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    z-index: 100;
    margin-bottom: 4px;
}

.card-transliteration {
    font-size: 1.25rem;
    color: var(--text-secondary);
    font-style: italic;
}

/* Card images for reviews */
.card-images {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    margin-top: 1.5rem;
}

.card-image {
    max-width: 300px;
    max-height: 200px;
    object-fit: contain;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* Card images for browser (thumbnails) */
.card-images-browser {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.75rem;
    margin: 1rem 0;
}

.card-image-thumb {
    max-width: 200px;
    max-height: 140px;
    object-fit: cover;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.card-divider {
    height: 2px;
    background: linear-gradient(to right, transparent, var(--border-color), transparent);
    margin: 1rem 0;
}

.card-back {
    text-align: center;
    padding: 1rem 0;
}

.card-pronunciation {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

.card-example {
    margin-top: 1.5rem;
    padding: 1rem;
    background-color: var(--bg-color);
    border-radius: 8px;
}

.example-text {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.example-translation {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.show-answer-container {
    text-align: center;
    padding: 2rem 0;
}

.show-answer-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 1rem 2rem;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
}

.show-answer-btn:hover {
    background-color: var(--primary-hover);
}

.review-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    margin-top: 2rem;
}

.review-btn {
    border: none;
    border-radius: 6px;
    padding: 0.5rem 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.1s, opacity 0.2s;
    color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.review-btn .btn-label {
    font-size: 0.875rem;
}

.review-btn .btn-interval {
    font-size: 0.75rem;
    opacity: 0.85;
    font-weight: 500;
}

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

.review-btn:active {
    transform: translateY(0);
}

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

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

.btn-good {
    background-color: var(--success-color);
}

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

.card-info {
    margin-top: 1rem;
}

.tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 0.5rem;
}

.tag {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 0.25rem 0.75rem;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.stats {
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Loading and Error States */
.loading, .error, .completed {
    text-align: center;
    padding: 3rem 1rem;
    background-color: var(--card-bg);
    border-radius: 12px;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

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

.completed h2 {
    color: var(--success-color);
    margin-bottom: 1rem;
}

button {
    cursor: pointer;
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Settings Page */
.settings-container {
    max-width: 600px;
    margin: 0 auto;
}

.settings-container h1 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--primary-color);
}

.settings-section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.settings-section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.push-status {
    text-align: center;
}

.push-status p {
    margin-bottom: 1rem;
}

.push-buttons {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    flex-wrap: wrap;
}

.status-enabled {
    color: var(--success-color);
    font-weight: 600;
}

.status-disabled {
    color: var(--text-secondary);
}

.status-blocked {
    color: var(--danger-color);
}

.toggle-row {
    margin-bottom: 1rem;
}

.toggle-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-weight: 500;
}

.toggle-label input[type="checkbox"] {
    width: 1.25rem;
    height: 1.25rem;
    cursor: pointer;
}

.times-list {
    margin-top: 1rem;
}

.times-help {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.time-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
}

.time-input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 1rem;
    max-width: 150px;
}

.time-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.save-section {
    margin-top: 1rem;
    text-align: center;
}

/* Buttons */
.btn {
    border: none;
    border-radius: 6px;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-hover);
}

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

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

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

.btn-danger:hover:not(:disabled) {
    opacity: 0.9;
}

.btn-small {
    padding: 0.5rem 0.75rem;
    font-size: 0.875rem;
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

/* Messages */
.error-message {
    background-color: #fef2f2;
    border: 1px solid var(--danger-color);
    color: var(--danger-color);
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.success-message {
    background-color: #f0fdf4;
    border: 1px solid var(--success-color);
    color: var(--success-color);
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

/* Auth Styles */
.login-container,
.callback-container,
.username-setup-container,
.loading-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: calc(100vh - 200px);
    padding: 2rem;
}

.login-card,
.callback-card,
.username-setup-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    text-align: center;
    max-width: 400px;
    width: 100%;
}

.login-card h1,
.username-setup-card h1 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.login-subtitle,
.setup-subtitle {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.google-login-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    width: 100%;
    padding: 0.875rem 1.5rem;
    background-color: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s;
}

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

.google-login-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.google-icon {
    flex-shrink: 0;
}

.test-login-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: 0.875rem 1.5rem;
    margin-top: 0.75rem;
    background-color: var(--bg-color);
    border: 1px dashed var(--border-color);
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s;
}

.test-login-btn:hover:not(:disabled) {
    background-color: var(--card-bg);
    border-color: var(--text-secondary);
    color: var(--text-primary);
}

.test-login-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.login-footer {
    margin-top: 2rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Profile picture in username setup */
.profile-picture {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    margin-bottom: 1.5rem;
    border: 3px solid var(--border-color);
}

/* Form styles for username setup */
.form-group {
    margin-bottom: 1.5rem;
    text-align: left;
}

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.form-input {
    width: 100%;
    padding: 0.875rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.2s;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-input:disabled {
    background-color: var(--bg-color);
    cursor: not-allowed;
}

.form-hint {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

/* Spinner for loading states */
.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    margin: 0 auto 1rem;
    animation: spin 1s linear infinite;
}

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

/* Navbar user section */
.nav-user {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-left: 1rem;
    padding-left: 1rem;
    border-left: 1px solid var(--border-color);
}

.nav-user-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
}

.nav-user-name {
    font-weight: 500;
    color: var(--text-primary);
    max-width: 150px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.nav-logout-btn {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.375rem 0.75rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s;
}

.nav-logout-btn:hover {
    border-color: var(--danger-color);
    color: var(--danger-color);
}
/* Restaurant Page */
.restaurant {
    max-width: 800px;
    margin: 0 auto;
}

.restaurant h1 {
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 2rem;
}

.restaurant-header {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.restaurant-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.restaurant-name {
    font-size: 1.5rem;
    color: var(--text-primary);
}

/* Stall visualization */
.stall-container {
    position: relative;
    width: 100%;
    max-width: 800px;
    margin: 0 auto 1.5rem auto;
}

.stall-background {
    width: 100%;
    height: auto;
    display: block;
}

/* Stats overlay styled as a small blackboard hanging on the wall */
.stall-stats-overlay {
    position: absolute;
    top: 30%;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(145deg, #2a3a2a 0%, #1a2a1a 50%, #0f1f0f 100%);
    border: 3px solid #5a4a3a;
    border-radius: 4px;
    padding: 0.4rem 0.6rem;
    color: #e8e8d8;
    text-align: center;
    box-shadow:
        inset 0 0 10px rgba(0, 0, 0, 0.5),
        2px 2px 8px rgba(0, 0, 0, 0.4);
    font-family: 'Chalk', 'Comic Sans MS', cursive, sans-serif;
    max-width: 25%;
}

.stall-currency {
    font-size: 1.1rem;
    font-weight: bold;
    color: #90ee90;
    margin-bottom: 0.2rem;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

.stall-currency .currency-symbol {
    color: #90ee90;
}

.stall-stats-row {
    display: flex;
    justify-content: space-around;
    gap: 0.4rem;
}

.stall-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stall-stat .stat-value {
    font-size: 0.85rem;
    font-weight: bold;
    color: #fffacd;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

.stall-stat .stat-label {
    font-size: 0.55rem;
    color: #d1d5db;
    text-transform: uppercase;
    text-shadow: 1px 1px 1px rgba(0, 0, 0, 0.5);
}

.meal-image {
    position: absolute;
    width: 11%;
    height: auto;
    transform: translate(-50%, -50%);
    border-radius: 4px;
    transition: transform 0.2s ease;
    z-index: 1;
}

.meal-image:hover {
    transform: translate(-50%, -50%) scale(1.15);
    z-index: 2;
}

.currency-balance {
    font-size: 1.75rem;
    font-weight: bold;
    color: var(--success-color);
}

.currency-symbol {
    margin-right: 0.25rem;
}

.stats-row {
    display: flex;
    justify-content: space-around;
    gap: 1rem;
}

.stat-item {
    text-align: center;
}

.stat-item .stat-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    display: block;
}

.stat-item .stat-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.earnings-section {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.earnings-section h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.earnings-info {
    margin-bottom: 1rem;
}

.earnings-info p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.potential-earnings {
    font-size: 1.125rem;
}

.potential-earnings strong {
    color: var(--success-color);
}

.collect-btn {
    background: var(--success-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 1rem 2rem;
    font-size: 1.125rem;
    font-weight: 600;
    width: 100%;
    transition: background-color 0.2s;
}

.collect-btn:hover:not(:disabled) {
    background: #059669;
}

.earnings-unavailable {
    text-align: center;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 8px;
}

.earnings-unavailable p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.recipes-section {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.recipes-section h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.recipes-section h4 {
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.recipes-unlocked {
    margin-bottom: 1.5rem;
}

.recipes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 1rem;
}

.recipe-card {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    text-align: center;
}

.recipe-card.unlocked {
    border-color: var(--success-color);
}

.recipe-card.locked {
    opacity: 0.6;
}

.recipe-icon {
    font-size: 2rem;
    display: block;
    margin-bottom: 0.5rem;
}

.recipe-icon.locked-icon {
    opacity: 0.5;
}

.recipe-name {
    font-weight: 600;
    display: block;
    margin-bottom: 0.25rem;
    font-size: 0.875rem;
}

.recipe-earnings {
    color: var(--success-color);
    font-size: 0.75rem;
    font-weight: 600;
}

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

.shop-section {
    text-align: center;
}

.shop-btn, .back-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    transition: background-color 0.2s;
}

.shop-btn:hover, .back-btn:hover {
    background: var(--primary-hover);
}

/* Shop Page */
.shop {
    max-width: 800px;
    margin: 0 auto;
}

.shop-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.shop-header h1 {
    color: var(--primary-color);
}

.shop-balance {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    text-align: center;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.balance-label {
    color: var(--text-secondary);
    margin-right: 0.5rem;
}

.balance-amount {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--success-color);
}

.upgrades-container {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.upgrade-category h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.upgrades-grid {
    display: grid;
    gap: 1rem;
}

.upgrade-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.upgrade-card.purchased {
    border-color: var(--success-color);
    background: linear-gradient(135deg, var(--card-bg) 0%, #ecfdf5 100%);
}

.upgrade-card.unaffordable {
    opacity: 0.6;
}

.upgrade-info {
    flex: 1;
}

.upgrade-name {
    font-size: 1.125rem;
    margin-bottom: 0.25rem;
}

.upgrade-description {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 0.25rem;
}

.upgrade-effect {
    color: var(--success-color);
    font-size: 0.875rem;
    font-weight: 600;
}

.upgrade-action {
    margin-left: 1rem;
}

.buy-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 0.75rem 1.25rem;
    font-weight: 600;
    transition: background-color 0.2s;
}

.buy-btn:hover:not(:disabled) {
    background: var(--primary-hover);
}

.owned-badge {
    background: var(--success-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .dashboard h1 {
        font-size: 2rem;
    }

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

    .card-text {
        font-size: 1.75rem;
    }

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

    .settings-container {
        padding: 0 0.5rem;
    }

    .time-row {
        flex-wrap: wrap;
    }

    .time-input {
        max-width: none;
    }

    /* Auth responsive */
    .nav-user {
        margin-left: 0.5rem;
        padding-left: 0.5rem;
    }

    .nav-user-name {
        display: none;
    }

    .nav-logout-btn {
        padding: 0.25rem 0.5rem;
        font-size: 0.75rem;
    }

    .login-card,
    .callback-card,
    .username-setup-card {
        padding: 1.5rem;
    }

    .login-card h1,
    .username-setup-card h1 {
        font-size: 1.5rem;
    }

    /* Restaurant/Shop responsive */
    .restaurant-info {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

    .stats-row {
        flex-direction: column;
        gap: 1rem;
    }

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

    .shop-header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

    .upgrade-card {
        flex-direction: column;
        text-align: center;
    }

    .upgrade-action {
        margin-left: 0;
        margin-top: 1rem;
    }
}

/* Offline/Sync Status Banners */
.offline-banner,
.sync-banner {
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    text-align: center;
    font-weight: 500;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.offline-banner {
    background-color: #fef3c7;
    color: #92400e;
    border: 1px solid #fcd34d;
}

.offline-banner::before {
    content: "";
    display: inline-block;
    width: 8px;
    height: 8px;
    background-color: #f59e0b;
    border-radius: 50%;
}

.sync-banner {
    background-color: #dbeafe;
    color: #1e40af;
    border: 1px solid #93c5fd;
}

.sync-banner::before {
    content: "";
    display: inline-block;
    width: 8px;
    height: 8px;
    background-color: #3b82f6;
    border-radius: 50%;
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.4;
    }
}

.pending-count {
    font-weight: 600;
}

/* Sync Indicator (Navbar) */
.sync-icon {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    cursor: default;
    color: var(--text-secondary);
    transition: color 0.2s;
}

.sync-icon.online {
    color: var(--success-color);
}

.sync-icon.offline {
    color: var(--text-secondary);
}

.sync-icon.syncing {
    color: var(--primary-color);
}

.sync-icon.syncing svg {
    animation: spin 1s linear infinite;
}

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

@keyframes spin {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

.sync-badge {
    position: absolute;
    top: 0;
    right: 0;
    background-color: var(--primary-color);
    color: white;
    font-size: 0.65rem;
    font-weight: 600;
    min-width: 16px;
    height: 16px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0 4px;
}

.sync-icon.offline .sync-badge {
    background-color: var(--warning-color);
}

.sync-icon.error .sync-badge {
    background-color: var(--danger-color);
}

/* Card Browser */
.card-browser {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
}

.card-browser h1 {
    margin-bottom: 1.5rem;
}

.browser-filters {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1rem;
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.1);
}

.filter-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.filter-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background: white;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.875rem;
}

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

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

.cards-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

@media (min-width: 900px) {
    .cards-list {
        grid-template-columns: repeat(2, 1fr);
    }
}

.cards-header {
    grid-column: 1 / -1;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.cards-count {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.pagination {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.pagination .btn-small {
    padding: 0.25rem 0.75rem;
    font-size: 0.875rem;
}

.pagination .page-info {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.browser-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.browser-card:hover {
    border-color: var(--primary-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.card-content {
    flex: 1;
    text-align: center;
}

.card-content .card-front {
    font-weight: 600;
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.card-content .card-transliteration {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-style: italic;
    margin-bottom: 0.5rem;
}

.card-content .card-back {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.card-meta {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.stage-badge {
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-weight: 500;
    font-size: 0.75rem;
}

.stage-new {
    background-color: #dbeafe;
    color: #1e40af;
}

.stage-learning {
    background-color: #fef3c7;
    color: #92400e;
}

.stage-review {
    background-color: #d1fae5;
    color: #065f46;
}

.stage-mastered {
    background-color: #ede9fe;
    color: #5b21b6;
}

.stage-not-started {
    background-color: #f3f4f6;
    color: #6b7280;
}

.no-cards-message {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
}

@media (max-width: 640px) {
    .card-browser {
        padding: 1rem;
    }
}

/* Card Browser Annotations */
.browser-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.browser-header h1 {
    margin: 0;
}

.download-csv-btn {
    white-space: nowrap;
}

.browser-hint {
    background-color: #f8f9fa;
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.browser-hint kbd {
    background-color: #e9ecef;
    border: 1px solid #dee2e6;
    border-radius: 0.25rem;
    padding: 0.125rem 0.375rem;
    font-family: monospace;
    font-size: 0.8rem;
}

.browser-card.selected {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px var(--primary-color);
}

.browser-card.has-annotation {
    background-color: #fffbeb;
}

.card-annotation {
    margin-top: 0.75rem;
    padding: 0.5rem;
    background-color: #fef3c7;
    border-radius: 0.25rem;
    font-size: 0.875rem;
    text-align: left;
}

.annotation-label {
    font-weight: 600;
    color: #92400e;
}

.annotation-badge {
    color: #d97706;
    font-weight: bold;
    font-size: 1rem;
}

/* Card details (POS and tags) */
.card-details {
    display: flex;
    flex-wrap: wrap;
    gap: 0.375rem;
    margin-top: 0.5rem;
    justify-content: center;
}

.pos-badge {
    display: inline-block;
    padding: 0.125rem 0.5rem;
    background-color: #e0e7ff;
    color: #4338ca;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    cursor: help;
    text-decoration: underline dotted;
    text-underline-offset: 2px;
}

.tag-badge {
    display: inline-block;
    padding: 0.125rem 0.5rem;
    background-color: #f3f4f6;
    color: #4b5563;
    border-radius: 0.25rem;
    font-size: 0.75rem;
}

/* Annotation Popup */
.annotation-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.annotation-popup {
    background: white;
    border-radius: 0.75rem;
    padding: 1.5rem;
    max-width: 500px;
    width: 90%;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.annotation-popup h3 {
    margin: 0 0 1rem 0;
    font-size: 1.25rem;
}

.annotation-card-preview {
    background-color: #f3f4f6;
    padding: 0.75rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    font-weight: 500;
    text-align: center;
}

.annotation-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1rem;
    resize: vertical;
    font-family: inherit;
}

.annotation-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(var(--primary-rgb, 79, 70, 229), 0.2);
}

.annotation-buttons {
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    margin-top: 1rem;
}

/* ==================== Grammar Lessons ==================== */

.grammar-lessons {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.grammar-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.grammar-subtitle {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.lessons-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.lesson-card {
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    cursor: pointer;
    transition: all 0.2s ease;
}

.lesson-card:hover:not(.lesson-locked) {
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.lesson-card.lesson-locked {
    opacity: 0.6;
    cursor: not-allowed;
    background: #f9fafb;
}

.lesson-card.lesson-completed {
    border-color: #10b981;
    background: linear-gradient(to right, #ecfdf5, white);
}

.lesson-card.lesson-in-progress {
    border-color: #f59e0b;
    background: linear-gradient(to right, #fffbeb, white);
}

.lesson-card.lesson-available {
    border-color: var(--primary-color);
}

.lesson-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.lesson-number {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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

.check-icon {
    font-size: 1.25rem;
    color: #10b981;
    font-weight: bold;
}

.lesson-name {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.lesson-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
    margin-bottom: 1rem;
}

.lesson-progress {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

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

.progress-bar {
    height: 6px;
    background: #e5e7eb;
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(to right, #f59e0b, #10b981);
    border-radius: 3px;
    transition: width 0.3s ease;
}

/* Lesson Detail View */

.lesson-detail {
    max-width: 800px;
    margin: 0 auto;
}

.back-button {
    margin-bottom: 1.5rem;
}

.lesson-detail-header {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.lesson-detail-header .lesson-number {
    display: block;
    margin-bottom: 0.5rem;
}

.lesson-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.completion-badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: #d1fae5;
    color: #065f46;
    border-radius: 9999px;
    font-weight: 600;
    font-size: 0.875rem;
}

.cards-badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: #fef3c7;
    color: #92400e;
    border-radius: 9999px;
    font-weight: 600;
    font-size: 0.875rem;
}

.lesson-explanation {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 2rem;
}

.explanation-content {
    line-height: 1.8;
    color: var(--text-primary);
}

.explanation-content p {
    margin-bottom: 1rem;
}

.explanation-content p:last-child {
    margin-bottom: 0;
}

.lesson-footer {
    text-align: center;
    padding: 1.5rem;
    background: #f3f4f6;
    border-radius: 12px;
}

.lesson-hint {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.no-lessons-message {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-secondary);
}

.no-lessons-message h2 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

@media (max-width: 640px) {
    .grammar-lessons {
        padding: 1rem;
    }

    .grammar-title {
        font-size: 1.5rem;
    }

    .lesson-card {
        padding: 1rem;
    }

    .lesson-explanation {
        padding: 1.25rem;
    }

    .lesson-title {
        font-size: 1.5rem;
    }
}

/* ==================== Vocabulary Groups ==================== */

.vocabulary-groups {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.vocabulary-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.vocabulary-subtitle {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.groups-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.group-card {
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    transition: all 0.2s ease;
}

.group-card:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.group-card.group-available {
    border-color: var(--primary-color);
}

.group-card.group-in-progress {
    border-color: #f59e0b;
    background: linear-gradient(to bottom right, #fffbeb, white);
}

.group-card.group-completed {
    border-color: #10b981;
    background: linear-gradient(to bottom right, #ecfdf5, white);
}

.group-card.group-completed-claimed {
    border-color: #6b7280;
    background: linear-gradient(to bottom right, #f3f4f6, white);
}

.group-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.75rem;
}

.group-name {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.reward-badge {
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 600;
    white-space: nowrap;
}

.group-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
    margin-bottom: 1rem;
}

.group-stats {
    display: flex;
    gap: 1rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.card-count,
.learned-count {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.group-card .progress-bar {
    margin-bottom: 1rem;
}

.group-actions {
    display: flex;
    justify-content: flex-end;
}

.complete-badge {
    background: #10b981;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.875rem;
}

.in-progress-badge {
    background: #f59e0b;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.875rem;
}

.no-groups-message {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
}

/* Reward Notification */
.reward-notification {
    position: fixed;
    top: 80px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    color: white;
    padding: 1rem 2rem;
    border-radius: 12px;
    box-shadow: 0 8px 32px rgba(245, 158, 11, 0.4);
    z-index: 1000;
    animation: reward-slide-in 0.4s ease-out, reward-fade-out 0.5s ease-in 2.5s forwards;
}

.reward-notification-content {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

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

.reward-text {
    font-weight: 600;
    font-size: 1rem;
}

.reward-amount {
    font-size: 1.25rem;
    font-weight: 700;
}

@keyframes reward-slide-in {
    from {
        transform: translateX(-50%) translateY(-20px);
        opacity: 0;
    }
    to {
        transform: translateX(-50%) translateY(0);
        opacity: 1;
    }
}

@keyframes reward-fade-out {
    from {
        opacity: 1;
    }
    to {
        opacity: 0;
        visibility: hidden;
    }
}

/* Responsive adjustments for vocabulary groups */
@media (max-width: 640px) {
    .vocabulary-groups {
        padding: 1rem;
    }

    .vocabulary-title {
        font-size: 1.5rem;
    }

    .groups-list {
        grid-template-columns: 1fr;
    }

    .group-card {
        padding: 1rem;
    }

    .group-header {
        flex-direction: column;
        gap: 0.5rem;
    }

    .reward-notification {
        left: 1rem;
        right: 1rem;
        transform: none;
        padding: 0.75rem 1rem;
    }

    @keyframes reward-slide-in {
        from {
            transform: translateY(-20px);
            opacity: 0;
        }
        to {
            transform: translateY(0);
            opacity: 1;
        }
    }
}