/* Modern CSS Design System for Notes App */
:root {
    --bg-main: #0f172a;
    --bg-surface: #1e293b;
    --bg-surface-hover: #334155;
    --bg-card: #1e293b;
    --bg-input: #0f172a;
    --border-color: #334155;
    --border-focus: #38bdf8;
    
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --text-dim: #64748b;
    
    --primary: #38bdf8;
    --primary-hover: #0ea5e9;
    --primary-dim: rgba(56, 189, 248, 0.15);
    
    --success: #10b981;
    --success-hover: #059669;
    --success-dim: rgba(16, 185, 129, 0.15);
    
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --danger-dim: rgba(239, 68, 68, 0.15);
    
    --tag-bg: #293548;
    --tag-text: #7dd3fc;
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-full: 9999px;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.4);
    
    --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --transition: all 0.18s ease-in-out;
}

[data-theme="light"] {
    --bg-main: #f1f5f9;
    --bg-surface: #ffffff;
    --bg-surface-hover: #f8fafc;
    --bg-card: #ffffff;
    --bg-input: #f8fafc;
    --border-color: #cbd5e1;
    --border-focus: #0284c7;
    
    --text-main: #0f172a;
    --text-muted: #475569;
    --text-dim: #94a3b8;
    
    --primary: #0284c7;
    --primary-hover: #0369a1;
    --primary-dim: rgba(2, 132, 199, 0.1);
    
    --success: #059669;
    --success-hover: #047857;
    --success-dim: rgba(5, 150, 105, 0.1);
    
    --tag-bg: #e2e8f0;
    --tag-text: #0369a1;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

body {
    background-color: var(--bg-main);
    color: var(--text-main);
    font-family: var(--font-family);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

.hidden {
    display: none !important;
}

/* Auth Screen / Login Overlay */
.auth-screen,
.login-overlay {
    position: fixed;
    inset: 0;
    z-index: 10000;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background-color: var(--bg-main);
    background-image: radial-gradient(circle at top, rgba(56, 189, 248, 0.15), transparent 70%);
}

.auth-card,
.login-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 36px 32px;
    width: 100%;
    max-width: 420px;
    box-shadow: var(--shadow-lg);
    animation: fadeInScale 0.2s ease-out;
}

@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.96);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.auth-header,
.login-header {
    text-align: center;
    margin-bottom: 28px;
}

.auth-header .app-logo,
.login-header .login-logo {
    font-size: 48px;
    margin-bottom: 8px;
    display: block;
}

.auth-header h2,
.login-header h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-main);
}

.auth-header p,
.login-header p {
    color: var(--text-muted);
    font-size: 14px;
    margin-top: 4px;
}

.login-form {
    display: flex;
    flex-direction: column;
}

.login-error {
    background-color: var(--danger-dim);
    color: var(--danger);
    border: 1px solid var(--danger);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin-bottom: 16px;
    text-align: center;
}

.auth-footer,
.login-footer {
    margin-top: 24px;
    text-align: center;
    font-size: 12px;
    color: var(--text-dim);
}

.form-group {
    margin-bottom: 18px;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.form-group input {
    width: 100%;
    padding: 12px 14px;
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: 15px;
    outline: none;
    transition: var(--transition);
}

.form-group input:focus {
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px var(--primary-dim);
}

.error-banner {
    background-color: var(--danger-dim);
    border: 1px solid var(--danger);
    color: #fca5a5;
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin-bottom: 16px;
}

.success-banner {
    background-color: var(--success-dim, rgba(16, 185, 129, 0.15));
    border: 1px solid var(--success, #10b981);
    color: #86efac;
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin-bottom: 16px;
}

/* App Navbar */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.navbar {
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    padding: 12px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 8px;
}

.brand-icon {
    font-size: 24px;
}

.brand-title {
    font-size: 20px;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.brand-sub {
    font-size: 12px;
    background-color: var(--primary-dim);
    color: var(--primary);
    padding: 2px 8px;
    border-radius: var(--radius-full);
    font-weight: 600;
    margin-left: 4px;
}

.nav-stats {
    display: flex;
    gap: 12px;
}

.stat-badge {
    font-size: 13px;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    padding: 4px 12px;
    border-radius: var(--radius-full);
    color: var(--text-muted);
}

.stat-badge strong {
    color: var(--text-main);
}

.stat-badge.stat-today strong {
    color: var(--success);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-profile {
    display: flex;
    align-items: center;
    gap: 8px;
}

.user-badge {
    font-size: 13px;
    color: var(--text-muted);
    font-weight: 600;
    background-color: var(--bg-surface-hover);
    padding: 4px 10px;
    border-radius: var(--radius-sm);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 18px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: var(--transition);
}

.btn-primary {
    background-color: var(--primary);
    color: #0f172a;
}

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

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

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

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

.btn-outline:hover {
    border-color: var(--text-main);
    color: var(--text-main);
}

.btn-sm {
    padding: 6px 12px;
    font-size: 12px;
}

.btn-lg {
    padding: 14px 24px;
    font-size: 16px;
}

.btn-block {
    width: 100%;
}

.btn-subtext {
    font-size: 11px;
    opacity: 0.8;
    margin-left: 4px;
}

.icon-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 6px 10px;
    cursor: pointer;
    color: var(--text-muted);
    font-size: 16px;
    transition: var(--transition);
}

.icon-btn:hover {
    color: var(--text-main);
    border-color: var(--text-main);
}

/* Main Content */
.main-content {
    max-width: 900px;
    width: 100%;
    margin: 0 auto;
    padding: 32px 20px;
    display: flex;
    flex-direction: column;
    gap: 36px;
}

/* Search Box */
.search-box-wrapper {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.search-input-box {
    display: flex;
    align-items: center;
    background-color: var(--bg-surface);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 6px 10px 6px 16px;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
}

.search-input-box:focus-within {
    border-color: var(--border-focus);
    box-shadow: 0 0 0 4px var(--primary-dim);
}

.search-icon {
    font-size: 18px;
    color: var(--text-muted);
    margin-right: 12px;
}

.search-input-box input {
    flex: 1;
    background: transparent;
    border: none;
    outline: none;
    font-size: 17px;
    color: var(--text-main);
    padding: 8px 0;
}

.clear-btn {
    background: transparent;
    border: none;
    color: var(--text-dim);
    font-size: 16px;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 50%;
}

.clear-btn:hover {
    color: var(--text-main);
}

.translate-action-btn {
    margin-left: 8px;
}

.hotkey-hints {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    padding: 4px 8px;
    font-size: 12px;
    color: var(--text-dim);
}

.hotkey-hints kbd {
    background-color: var(--bg-surface-hover);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 1px 5px;
    font-family: monospace;
    font-size: 11px;
    color: var(--text-muted);
}

/* Spinner */
.lookup-spinner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 24px;
    color: var(--primary);
    font-size: 14px;
    font-weight: 500;
}

.spinner {
    width: 24px;
    height: 24px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Live Result Card */
.result-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-md);
    animation: fadeIn 0.25s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
}

.result-header {
    margin-bottom: 16px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.term-title-row {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.res-term {
    font-size: 28px;
    font-weight: 800;
    letter-spacing: -0.5px;
    color: var(--text-main);
}

.badge-pill {
    padding: 3px 10px;
    border-radius: var(--radius-full);
    font-size: 13px;
    font-weight: 600;
}

.res-phonetic {
    background-color: var(--primary-dim);
    color: var(--primary);
    font-family: monospace;
}

.res-pos {
    background-color: var(--bg-surface-hover);
    color: var(--text-muted);
}

.audio-btn {
    background-color: var(--primary-dim);
    border: 1px solid var(--primary);
    color: var(--primary);
    border-radius: var(--radius-full);
    padding: 4px 12px;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    transition: var(--transition);
}

.audio-btn:hover {
    background-color: var(--primary);
    color: #0f172a;
}

.definition-box {
    background-color: var(--bg-main);
    border-left: 3px solid var(--primary);
    padding: 12px 16px;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin-bottom: 20px;
}

.def-label {
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--primary);
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.def-text {
    font-size: 14px;
    color: var(--text-main);
}

.card-edit-grid {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-bottom: 24px;
}

.input-styled {
    width: 100%;
    padding: 10px 14px;
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: 14px;
    outline: none;
    transition: var(--transition);
}

.input-styled:focus {
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px var(--primary-dim);
}

.field-group label {
    display: block;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 5px;
}

.field-group .req {
    color: var(--danger);
}

.field-row {
    display: flex;
    gap: 16px;
}

.flex-1 { flex: 1; }
.flex-2 { flex: 2; }

.suggestions-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 6px;
}

.suggestion-chip {
    font-size: 12px;
    background-color: var(--bg-surface-hover);
    color: var(--text-muted);
    padding: 2px 8px;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: var(--transition);
    border: 1px solid transparent;
}

.suggestion-chip:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.quick-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 6px;
}

.tag-chip {
    font-size: 11px;
    background-color: var(--tag-bg);
    color: var(--tag-text);
    padding: 2px 8px;
    border-radius: var(--radius-full);
    cursor: pointer;
    user-select: none;
    transition: var(--transition);
}

.tag-chip:hover, .tag-chip.active {
    background-color: var(--primary);
    color: #0f172a;
    font-weight: 600;
}

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

/* Vocabulary Section */
.vocabulary-section {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.section-title-wrap {
    display: flex;
    align-items: baseline;
    gap: 8px;
}

.section-title-wrap h3 {
    font-size: 20px;
    font-weight: 700;
}

.cards-count-label {
    font-size: 13px;
    color: var(--text-dim);
}

.list-controls {
    display: flex;
    align-items: center;
    gap: 8px;
}

.batch-mode-btn {
    white-space: nowrap;
    flex-shrink: 0;
    height: 35px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.search-mini-box {
    display: flex;
    align-items: center;
}

.search-mini-box input {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 8px 12px;
    color: var(--text-main);
    font-size: 13px;
    outline: none;
    min-width: 260px;
    height: 35px;
    box-sizing: border-box;
    transition: var(--transition);
}

.search-mini-box input:focus {
    border-color: var(--border-focus);
}

/* Tags Filter Bar */
.tags-filter-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.filter-chip {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 12px;
    font-weight: 600;
    padding: 4px 12px;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: var(--transition);
}

.filter-chip:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.filter-chip.active {
    background-color: var(--primary);
    border-color: var(--primary);
    color: #0f172a;
}

/* Cards List */
.cards-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.vocab-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.vocab-card:hover {
    border-color: var(--border-focus);
    box-shadow: var(--shadow-md);
}

.card-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

.card-term-group {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.card-term {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-main);
}

.card-phonetic {
    font-size: 13px;
    color: var(--primary);
    font-family: monospace;
}

.card-pos {
    font-size: 11px;
    background-color: var(--bg-surface-hover);
    color: var(--text-dim);
    padding: 2px 6px;
    border-radius: 4px;
}

.card-actions {
    display: flex;
    gap: 6px;
}

.card-translation {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-main);
}

.card-context {
    font-size: 14px;
    color: var(--text-muted);
    font-style: italic;
    background-color: var(--bg-main);
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    border-left: 2px solid var(--border-color);
}

.card-context mark {
    background-color: var(--primary-dim);
    color: var(--primary);
    font-weight: 600;
    padding: 0 4px;
    border-radius: 2px;
}

.card-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    font-size: 12px;
    color: var(--text-dim);
}

.card-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.card-tag {
    background-color: var(--tag-bg);
    color: var(--tag-text);
    padding: 2px 8px;
    border-radius: var(--radius-full);
    font-size: 11px;
}

.card-notes {
    font-size: 12px;
    color: #fbbf24;
    display: flex;
    align-items: center;
    gap: 4px;
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 48px 24px;
    background-color: var(--bg-surface);
    border: 1px dashed var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-muted);
}

.empty-icon {
    font-size: 40px;
    margin-bottom: 12px;
}

.empty-state h4 {
    font-size: 16px;
    color: var(--text-main);
    margin-bottom: 6px;
}

.empty-state p {
    font-size: 13px;
    color: var(--text-dim);
}

/* Modal */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}

.modal-window {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 520px;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 18px;
    font-weight: 700;
}

.modal-body {
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    padding: 14px 20px;
    border-top: 1px solid var(--border-color);
}

.modal-sm {
    max-width: 420px;
}

/* Navigation Additions */
.nav-center {
    display: flex;
    align-items: center;
}

.btn-trainer {
    background: linear-gradient(135deg, #0284c7, #38bdf8);
    color: #0f172a;
    font-weight: 700;
    box-shadow: 0 2px 10px rgba(56, 189, 248, 0.25);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 14px;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    transition: var(--transition);
}

.btn-trainer:hover {
    box-shadow: 0 4px 14px rgba(56, 189, 248, 0.45);
    transform: translateY(-1px);
}

.srs-due-badge {
    background-color: #0f172a;
    color: #38bdf8;
    font-size: 11px;
    font-weight: 800;
    padding: 1px 7px;
    border-radius: var(--radius-full);
    min-width: 18px;
    text-align: center;
}

.srs-due-badge.has-due {
    background-color: #ef4444;
    color: #ffffff;
    animation: pulseDue 2s infinite;
}

@keyframes pulseDue {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.15); }
}

/* Collections & Filters */
.collections-filter-wrap, .tags-filter-wrap {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.filter-header-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.filter-title {
    font-size: 12px;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.filter-chips-row {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    align-items: center;
}

.col-chip {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 12px;
    font-weight: 600;
    padding: 4px 12px;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: var(--transition);
}

.col-chip:hover {
    border-color: #a855f7;
    color: #c084fc;
}

.col-chip.active {
    background-color: #a855f7;
    border-color: #a855f7;
    color: #ffffff;
    font-weight: 700;
}

.card-collection-badge {
    font-size: 11px;
    font-weight: 600;
    background-color: rgba(168, 85, 247, 0.15);
    color: #c084fc;
    border: 1px solid rgba(168, 85, 247, 0.3);
    padding: 2px 8px;
    border-radius: var(--radius-full);
}

/* Batch Selection */
.batch-mode-btn.active {
    background-color: var(--primary-dim);
    border-color: var(--primary);
    color: var(--primary);
}

.card-select-cell {
    display: none;
    margin-right: 12px;
    align-items: center;
}

.batch-active .card-select-cell {
    display: flex;
}

.card-select-checkbox {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--primary);
}

.vocab-card.is-selected {
    border-color: var(--border-focus);
    background-color: rgba(56, 189, 248, 0.05);
}

.batch-action-bar {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    width: calc(100% - 32px);
    max-width: 760px;
    background: rgba(30, 41, 59, 0.96);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border-focus);
    border-radius: var(--radius-lg);
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.6), 0 0 15px rgba(56, 189, 248, 0.2);
    padding: 12px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 900;
    animation: slideUp 0.22s ease-out;
}

@keyframes slideUp {
    from { transform: translate(-50%, 40px); opacity: 0; }
    to { transform: translate(-50%, 0); opacity: 1; }
}

.batch-left {
    display: flex;
    align-items: center;
    gap: 10px;
}

.batch-check-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-main);
    cursor: pointer;
}

.batch-master-checkbox {
    width: 18px;
    height: 18px;
    accent-color: var(--primary);
    cursor: pointer;
}

.batch-actions {
    display: flex;
    align-items: center;
    gap: 8px;
}

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

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

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

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

.btn-ghost {
    background: transparent;
    border: none;
    color: var(--primary);
    cursor: pointer;
    font-size: 13px;
    padding: 4px 8px;
    border-radius: var(--radius-sm);
}

.btn-ghost:hover {
    background-color: var(--primary-dim);
}

.btn-xs {
    padding: 2px 8px;
    font-size: 11px;
}

/* Export Modal */
.export-modal-window {
    max-width: 620px;
}

.modal-lead {
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.export-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.export-tile {
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 12px;
    transition: var(--transition);
}

.export-tile:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.export-tile-icon {
    font-size: 28px;
}

.export-tile-info h4 {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 4px;
}

.export-tile-info p {
    font-size: 12px;
    color: var(--text-dim);
    line-height: 1.4;
}

/* SRS View Structure */
.srs-view {
    min-height: calc(100vh - 65px);
    display: flex;
    flex-direction: column;
    background: radial-gradient(circle at 50% 15%, rgba(56, 189, 248, 0.07), transparent 60%);
}

.srs-topbar {
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    padding: 12px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.srs-topbar-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.srs-mode-switch {
    display: flex;
    background-color: var(--bg-main);
    padding: 3px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.srs-tab {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.srs-tab:hover {
    color: var(--text-main);
}

.srs-tab.active {
    background-color: var(--primary);
    color: #0f172a;
    font-weight: 700;
    box-shadow: var(--shadow-sm);
}

.srs-topbar-center {
    flex: 1;
    max-width: 380px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.srs-progress-container {
    width: 100%;
    height: 7px;
    background-color: var(--bg-main);
    border-radius: var(--radius-full);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.srs-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #0284c7, #38bdf8);
    border-radius: var(--radius-full);
    transition: width 0.3s ease;
}

.srs-counter {
    font-size: 11px;
    font-weight: 600;
    color: var(--text-dim);
}

.srs-topbar-right {
    display: flex;
    align-items: center;
}

.srs-arena {
    flex: 1;
    max-width: 720px;
    width: 100%;
    margin: 0 auto;
    padding: 32px 16px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.srs-state-box {
    text-align: center;
    padding: 64px 24px;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.srs-big-icon {
    font-size: 56px;
}

.srs-empty-buttons {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    justify-content: center;
    margin-top: 12px;
}

/* Flashcard 3D Card Flip */
.srs-mode-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
    animation: fadeIn 0.25s ease-out;
}

.flashcard-wrapper {
    perspective: 1400px;
    min-height: 380px;
    cursor: pointer;
    user-select: none;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    min-height: 380px;
    transform-style: preserve-3d;
    transition: transform 0.48s cubic-bezier(0.4, 0, 0.2, 1);
}

.flashcard-inner.is-flipped {
    transform: rotateY(180deg);
}

.flashcard-face {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    min-height: 380px;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 28px 32px;
    box-shadow: var(--shadow-lg);
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.flashcard-front {
    transform: rotateY(0deg);
}

.flashcard-back {
    transform: rotateY(180deg);
    background: radial-gradient(circle at top right, rgba(56, 189, 248, 0.06), var(--bg-card) 70%);
}

.fc-badge-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.fc-dir-badge {
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.5px;
    color: var(--primary);
    background-color: var(--primary-dim);
    padding: 3px 10px;
    border-radius: var(--radius-full);
}

.fc-pos-badge {
    font-size: 11px;
    color: var(--text-dim);
    background-color: var(--bg-surface-hover);
    padding: 2px 8px;
    border-radius: 4px;
}

.fc-center {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    gap: 16px;
    padding: 20px 0;
}

.fc-main-term {
    font-size: 38px;
    font-weight: 800;
    letter-spacing: -0.5px;
    color: var(--text-main);
}

.fc-phonetic-row {
    display: flex;
    align-items: center;
    gap: 10px;
}

.audio-round-btn {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background-color: var(--primary-dim);
    border: 1px solid var(--primary);
    color: var(--primary);
    font-size: 16px;
    cursor: pointer;
    transition: var(--transition);
}

.audio-round-btn:hover {
    background-color: var(--primary);
    color: #0f172a;
    transform: scale(1.08);
}

.fc-hint-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    max-width: 500px;
}

.fc-hint-content {
    font-size: 14px;
    font-style: italic;
    color: var(--text-muted);
    background-color: var(--bg-main);
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--primary);
}

.fc-footer-hint {
    text-align: center;
    font-size: 12px;
    color: var(--text-dim);
}

.fc-footer-hint kbd {
    background-color: var(--bg-surface-hover);
    border: 1px solid var(--border-color);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: monospace;
}

/* Flashcard Back */
.fc-back-content {
    display: flex;
    flex-direction: column;
    gap: 14px;
    height: 100%;
}

.fc-back-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 8px;
}

.fc-back-term {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-main);
}

.fc-back-translation {
    font-size: 22px;
    font-weight: 700;
    color: var(--primary);
}

.fc-back-detail-box {
    background-color: var(--bg-main);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    border-left: 2px solid var(--border-color);
}

.detail-label {
    font-size: 10px;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--text-dim);
    letter-spacing: 0.5px;
    margin-bottom: 2px;
    display: block;
}

.detail-text {
    font-size: 13px;
    color: var(--text-main);
    line-height: 1.4;
}

.fc-flip-btn-wrap {
    display: none;
}

/* SRS Rating Bar */
.srs-rating-bar {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-top: 8px;
    animation: fadeIn 0.2s ease-out;
}

.btn-rate {
    padding: 12px 10px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background-color: var(--bg-surface);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    transition: var(--transition);
}

.btn-rate .rate-key {
    font-size: 11px;
    font-family: monospace;
    opacity: 0.7;
}

.btn-rate .rate-name {
    font-size: 15px;
    font-weight: 700;
}

.btn-rate .rate-time {
    font-size: 11px;
    opacity: 0.75;
}

/* Rating variants */
.btn-rate-1 {
    border-color: rgba(239, 68, 68, 0.4);
    color: #f87171;
}
.btn-rate-1:hover {
    background-color: rgba(239, 68, 68, 0.15);
    border-color: #ef4444;
}

.btn-rate-2 {
    border-color: rgba(245, 158, 11, 0.4);
    color: #fbbf24;
}
.btn-rate-2:hover {
    background-color: rgba(245, 158, 11, 0.15);
    border-color: #f59e0b;
}

.btn-rate-3 {
    border-color: rgba(56, 189, 248, 0.4);
    color: #38bdf8;
}
.btn-rate-3:hover {
    background-color: rgba(56, 189, 248, 0.15);
    border-color: #38bdf8;
}

.btn-rate-4 {
    border-color: rgba(16, 185, 129, 0.4);
    color: #34d399;
}
.btn-rate-4:hover {
    background-color: rgba(16, 185, 129, 0.15);
    border-color: #10b981;
}

/* Interactive Trainer Card (Cloze & Dictation) */
.trainer-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.trainer-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.mode-tag {
    font-size: 12px;
    font-weight: 700;
    color: var(--primary);
    background-color: var(--primary-dim);
    padding: 3px 12px;
    border-radius: var(--radius-full);
}

.trainer-pos {
    font-size: 12px;
    color: var(--text-dim);
}

.cloze-sentence-display {
    font-size: 20px;
    line-height: 1.6;
    color: var(--text-main);
    background-color: var(--bg-main);
    padding: 20px 24px;
    border-radius: var(--radius-md);
    border-left: 4px solid var(--primary);
}

.gap-placeholder {
    color: var(--primary);
    font-weight: 800;
    letter-spacing: 2px;
    border-bottom: 2px dashed var(--primary);
    padding: 0 4px;
}

.cloze-translation-hint {
    font-size: 14px;
    color: var(--text-muted);
}

.cloze-translation-hint strong {
    color: var(--text-main);
    margin-left: 6px;
}

.trainer-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.input-action-row {
    display: flex;
    gap: 10px;
}

.input-hero {
    font-size: 18px;
    padding: 12px 18px;
}

.trainer-feedback-box {
    padding: 14px 18px;
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-weight: 600;
    animation: fadeIn 0.2s ease-out;
}

.trainer-feedback-box.correct {
    background-color: var(--success-dim);
    border: 1px solid var(--success);
    color: #34d399;
}

.trainer-feedback-box.incorrect {
    background-color: var(--danger-dim);
    border: 1px solid var(--danger);
    color: #fca5a5;
}

.trainer-revealed-details {
    background-color: var(--bg-main);
    border-radius: var(--radius-md);
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    border: 1px solid var(--border-color);
    animation: fadeIn 0.2s ease-out;
}

/* Audio Dictation Mode */
.dictation-hero {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
    padding: 16px 0;
}

.dictation-pulse-btn {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, #0284c7, #38bdf8);
    border: none;
    color: #0f172a;
    font-size: 34px;
    cursor: pointer;
    box-shadow: 0 0 0 0 rgba(56, 189, 248, 0.4);
    animation: pulseAudio 2s infinite;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.dictation-pulse-btn:hover {
    transform: scale(1.08);
}

@keyframes pulseAudio {
    0% { box-shadow: 0 0 0 0 rgba(56, 189, 248, 0.6); }
    70% { box-shadow: 0 0 0 22px rgba(56, 189, 248, 0); }
    100% { box-shadow: 0 0 0 0 rgba(56, 189, 248, 0); }
}

.dictation-instructions {
    font-size: 14px;
    color: var(--text-muted);
}

.audio-replay-btn .kbd-sub {
    font-size: 10px;
    margin-left: 4px;
}

.dictation-hint-wrap {
    display: flex;
    align-items: center;
    gap: 10px;
}

.dictation-hint-text {
    font-size: 13px;
    color: var(--text-muted);
    font-style: italic;
}

/* Summary Card */
.srs-summary-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 44px 32px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    box-shadow: var(--shadow-lg);
    animation: fadeIn 0.3s ease-out;
}

.summary-trophy {
    font-size: 64px;
    animation: bounce 0.6s ease;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-16px); }
}

.srs-summary-card h2 {
    font-size: 28px;
    font-weight: 800;
}

.summary-lead {
    font-size: 15px;
    color: var(--text-muted);
    max-width: 480px;
}

.summary-metrics {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    width: 100%;
    margin: 12px 0;
}

.metric-card {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.metric-val {
    font-size: 28px;
    font-weight: 800;
}

.metric-desc {
    font-size: 11px;
    color: var(--text-dim);
}

.text-success { color: var(--success); }
.text-primary { color: var(--primary); }

.summary-rates-bar {
    display: flex;
    gap: 12px;
    font-size: 13px;
    color: var(--text-muted);
    flex-wrap: wrap;
    justify-content: center;
}

.summary-buttons {
    display: flex;
    gap: 14px;
    margin-top: 12px;
    flex-wrap: wrap;
    justify-content: center;
}

/* Duplicate Warning Banner */
.duplicate-warning-box {
    margin-top: 10px;
    padding: 10px 14px;
    background: rgba(234, 179, 8, 0.12);
    border: 1px solid rgba(234, 179, 8, 0.35);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    animation: fadeIn 0.2s ease-in-out;
}

.dup-left {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: #facc15;
}

.dup-icon {
    font-size: 16px;
}

/* Multiple Choice Quiz Mode */
.quiz-card {
    max-width: 680px;
    margin: 0 auto;
}

.quiz-hero {
    text-align: center;
    padding: 20px 0 16px 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 20px;
}

.quiz-prompt-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
}

.quiz-term-display {
    font-size: 32px;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: -0.02em;
}

.quiz-context-hint {
    margin-top: 8px;
    font-size: 14px;
    color: var(--text-muted);
    font-style: italic;
}

.quiz-options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
    margin-bottom: 16px;
}

.quiz-option-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 18px;
    background: var(--bg-main);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-main);
    font-size: 15px;
    font-weight: 600;
    text-align: left;
    cursor: pointer;
    transition: all 0.15s ease;
    user-select: none;
}

.quiz-option-btn:hover:not(:disabled) {
    border-color: var(--primary);
    background: var(--bg-surface-hover);
    transform: translateY(-1px);
}

.quiz-option-btn:disabled {
    cursor: default;
}

.quiz-opt-num {
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: 700;
    color: var(--text-muted);
    flex-shrink: 0;
}

.quiz-opt-text {
    flex: 1;
    line-height: 1.35;
}

.quiz-option-btn.opt-correct {
    background: rgba(34, 197, 94, 0.15) !important;
    border-color: var(--success) !important;
    color: var(--success) !important;
}

.quiz-option-btn.opt-correct .quiz-opt-num {
    background: var(--success);
    color: #ffffff;
    border-color: var(--success);
}

.quiz-option-btn.opt-wrong {
    background: rgba(239, 68, 68, 0.15) !important;
    border-color: var(--danger) !important;
    color: var(--danger) !important;
    animation: shake 0.3s ease;
}

.quiz-option-btn.opt-wrong .quiz-opt-num {
    background: var(--danger);
    color: #ffffff;
    border-color: var(--danger);
}

.quiz-next-bar {
    margin-top: 16px;
}

/* Active Typing Mode */
.typing-hero {
    text-align: center;
    padding: 16px 0 20px 0;
}

.typing-prompt-ru {
    font-size: 28px;
    font-weight: 800;
    color: var(--primary);
    margin: 8px 0;
}

.typing-context-hint {
    font-size: 14px;
    color: var(--text-muted);
    font-style: italic;
    background: var(--bg-main);
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    display: inline-block;
    max-width: 90%;
    margin-top: 4px;
}

/* Analytics & Activity Heatmap Modal */
.stats-modal-window {
    max-width: 820px;
    width: 95%;
}

.stats-hero-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-bottom: 24px;
}

.stat-kpi-card {
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 14px 12px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.streak-kpi {
    border-color: rgba(249, 115, 22, 0.4);
    background: rgba(249, 115, 22, 0.05);
}

.kpi-icon {
    font-size: 24px;
}

.kpi-value {
    font-size: 26px;
    font-weight: 800;
    line-height: 1.1;
}

.kpi-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
}

.kpi-sub {
    font-size: 11px;
    color: var(--text-dim);
}

.text-accent {
    color: #38bdf8;
}

/* GitHub Heatmap Section */
.heatmap-section {
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    margin-bottom: 20px;
}

.heatmap-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 14px;
    flex-wrap: wrap;
    gap: 8px;
}

.heatmap-header h4 {
    font-size: 15px;
    font-weight: 700;
}

.heatmap-legend {
    display: flex;
    align-items: center;
    gap: 5px;
    font-size: 11px;
    color: var(--text-dim);
}

.legend-cell {
    width: 12px;
    height: 12px;
    border-radius: 2px;
    display: inline-block;
}

.heatmap-container-wrap {
    overflow-x: auto;
    padding-bottom: 6px;
}

.heatmap-grid {
    display: grid;
    grid-auto-flow: column;
    grid-template-rows: repeat(7, 12px);
    gap: 4px;
    min-width: 600px;
}

.heatmap-cell {
    width: 12px;
    height: 12px;
    border-radius: 2px;
    background: rgba(255, 255, 255, 0.05);
    cursor: pointer;
    transition: transform 0.1s ease;
    position: relative;
}

.heatmap-cell:hover {
    transform: scale(1.3);
    z-index: 10;
    outline: 1px solid var(--text-main);
}

/* Heatmap Levels (GitHub-style intensity) */
.lvl-0 { background: rgba(255, 255, 255, 0.06); }
.lvl-1 { background: #166534; }  /* 1 review: soft green */
.lvl-2 { background: #22c55e; }  /* 2-3 reviews: vibrant green */
.lvl-3 { background: #4ade80; }  /* 4+ reviews: bright intense green */

[data-theme="light"] .lvl-0 { background: #e2e8f0; }
[data-theme="light"] .lvl-1 { background: #86efac; }
[data-theme="light"] .lvl-2 { background: #22c55e; }
[data-theme="light"] .lvl-3 { background: #15803d; }

.heatmap-footer-note {
    margin-top: 10px;
    color: var(--text-dim);
    font-size: 11px;
}

/* Segmented Mastery Progress Bar */
.mastery-section {
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
}

.mastery-section h4 {
    font-size: 15px;
    font-weight: 700;
    margin-bottom: 12px;
}

.segmented-progress-bar {
    display: flex;
    height: 14px;
    background: var(--bg-surface);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-bottom: 12px;
    border: 1px solid var(--border-color);
}

.prog-segment {
    height: 100%;
    transition: width 0.3s ease;
}

.seg-mastered { background: #22c55e; }
.seg-review   { background: #38bdf8; }
.seg-learning { background: #f59e0b; }
.seg-new      { background: #64748b; }

.mastery-legend-row {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    font-size: 12px;
}

.m-legend-item {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text-muted);
}

.dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: inline-block;
}

.dot-mastered { background: #22c55e; }
.dot-review   { background: #38bdf8; }
.dot-learning { background: #f59e0b; }
.dot-new      { background: #64748b; }
.dot-leech    { background: #ef4444; }

.text-danger  { color: #ef4444; }

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    75% { transform: translateX(4px); }
}

/* Responsive */
@media (max-width: 640px) {
    .navbar {
        padding: 10px 14px;
    }
    .brand-sub {
        display: none;
    }
    .trainer-text {
        display: none;
    }
    .main-content {
        padding: 16px 12px;
        gap: 24px;
    }
    .field-row {
        flex-direction: column;
    }
    .res-term {
        font-size: 22px;
    }
    .list-controls {
        width: 100%;
        display: flex;
        align-items: center;
        gap: 8px;
    }
    .search-mini-box {
        flex: 1;
    }
    .search-mini-box input {
        min-width: 0;
        width: 100%;
    }
    .fc-flip-btn-wrap {
        display: block;
    }
    .srs-topbar {
        padding: 10px 12px;
        flex-direction: column;
        align-items: stretch;
        gap: 8px;
    }
    .srs-topbar-left, .srs-topbar-right {
        justify-content: space-between;
    }
    .srs-mode-switch {
        overflow-x: auto;
    }
    .srs-rating-bar {
        grid-template-columns: 1fr 1fr;
    }
    .quiz-options-grid {
        grid-template-columns: 1fr;
    }
    .stats-hero-grid {
        grid-template-columns: 1fr 1fr;
    }
    .export-grid {
        grid-template-columns: 1fr;
    }
    .summary-metrics {
        grid-template-columns: 1fr;
    }
    .batch-action-bar {
        flex-direction: column;
        gap: 10px;
        bottom: 12px;
    }
    .batch-actions {
        width: 100%;
        justify-content: space-between;
    }
}

/* ==========================================================================
   Stage 5: Interactive Reader & Bookshelf Styles
   ========================================================================== */

.reader-view {
    max-width: 1100px;
    margin: 0 auto;
    padding: 24px 20px 80px;
}

.bookshelf-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    margin-bottom: 28px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

.bookshelf-title-wrap h2 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 8px;
}

.bookshelf-title-wrap .subtitle {
    font-size: 14px;
    color: var(--text-muted);
    margin-top: 4px;
}

.bookshelf-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.file-upload-label {
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.bookshelf-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.book-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 20px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: var(--transition);
    position: relative;
    box-shadow: var(--shadow-sm);
}

.book-card:hover {
    border-color: var(--border-focus);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.book-card-top {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    margin-bottom: 14px;
}

.book-cover-icon {
    font-size: 32px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    width: 52px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.book-card-info {
    flex: 1;
    min-width: 0;
}

.book-card-title {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 4px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.book-card-author {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 8px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.book-card-badges {
    display: flex;
    align-items: center;
    gap: 8px;
}

.badge-format {
    text-transform: uppercase;
    font-size: 10px;
    font-weight: 700;
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    background: var(--tag-bg);
    color: var(--tag-text);
}

.badge-words {
    font-size: 12px;
    color: var(--text-dim);
}

.book-progress-wrap {
    margin: 14px 0 16px;
}

.book-progress-labels {
    display: flex;
    justify-content: space-between;
    font-size: 12px;
    color: var(--text-dim);
    margin-bottom: 6px;
}

.book-progress-bar-bg {
    width: 100%;
    height: 6px;
    background-color: var(--bg-input);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.book-progress-bar-fill {
    height: 100%;
    background-color: var(--primary);
    border-radius: var(--radius-full);
    transition: width 0.3s ease;
}

.book-card-actions {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    padding-top: 12px;
    border-top: 1px solid var(--border-color);
}

/* Reader Interface */
.reader-interface {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.reader-toolbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    padding: 12px 18px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.reader-toolbar-left {
    display: flex;
    align-items: center;
    gap: 14px;
}

.reader-meta {
    display: flex;
    flex-direction: column;
}

.reader-title {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-main);
    line-height: 1.2;
}

.reader-author {
    font-size: 12px;
    color: var(--text-muted);
}

.reader-toolbar-center {
    display: flex;
    align-items: center;
    gap: 8px;
}

.reader-select {
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    background-color: var(--bg-input);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    font-size: 13px;
    outline: none;
    max-width: 240px;
}

.reader-toolbar-right {
    display: flex;
    align-items: center;
    gap: 10px;
}

.font-controls {
    display: flex;
    align-items: center;
    gap: 4px;
}

.reader-scroll-area {
    padding: 36px 24px 60px;
    max-width: 780px;
    margin: 0 auto;
    min-height: 60vh;
}

.reader-content-body {
    font-family: Georgia, 'Times New Roman', serif;
    font-size: 19px;
    line-height: 1.85;
    color: var(--text-main);
    word-break: break-word;
    user-select: text;
}

.reader-content-body h1,
.reader-content-body h2,
.reader-content-body h3,
.reader-content-body h4,
.reader-content-body h5,
.reader-content-body h6 {
    font-family: var(--font-family);
    margin: 28px 0 16px;
    color: var(--text-main);
    text-indent: 0;
}

.reader-content-body h4 { font-size: 1.15em; }
.reader-content-body h5 { font-size: 1.05em; }

.reader-content-body p {
    margin-bottom: 20px;
    text-indent: 1.2em;
}

/* Fenced Code Block */
.reader-code-block {
    margin: 24px 0;
    border-radius: var(--radius-md);
    background: #141820;
    border: 1px solid var(--border-color);
    overflow: hidden;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
}

.reader-code-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 14px;
    background: rgba(255, 255, 255, 0.04);
    border-bottom: 1px solid var(--border-color);
    font-family: monospace;
    font-size: 12px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.reader-code-lang {
    font-weight: 600;
}

.reader-copy-code-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    border-radius: 4px;
    padding: 3px 8px;
    font-size: 11px;
    cursor: pointer;
    transition: all 0.15s ease;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.reader-copy-code-btn:hover {
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-main);
    border-color: var(--primary);
}

.reader-content-body pre {
    margin: 0;
    padding: 16px;
    overflow-x: auto;
    background: transparent;
    border: none;
    border-radius: 0;
    font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 14.5px;
    line-height: 1.6;
    text-indent: 0 !important;
    white-space: pre;
    tab-size: 4;
}

.reader-content-body pre code {
    font-family: inherit;
    font-size: inherit;
    color: #e6edf3;
    background: transparent;
    padding: 0;
    border: none;
    white-space: pre;
    display: block;
    text-indent: 0;
}

/* Inline Code Badge */
.reader-inline-code {
    font-family: 'JetBrains Mono', 'Consolas', monospace;
    font-size: 0.88em;
    background: rgba(255, 255, 255, 0.08);
    color: var(--primary);
    padding: 2px 6px;
    border-radius: 4px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    white-space: pre-wrap;
    word-break: break-all;
}

/* Blockquote */
.reader-content-body blockquote {
    margin: 20px 0;
    padding: 12px 20px;
    border-left: 4px solid var(--primary);
    background: rgba(56, 189, 248, 0.06);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    font-style: italic;
    color: var(--text-main);
    text-indent: 0;
}

.reader-content-body blockquote p {
    margin: 0;
    text-indent: 0;
}

/* Lists */
.reader-content-body ul,
.reader-content-body ol {
    margin: 16px 0 20px 24px;
    padding-left: 12px;
    text-indent: 0;
}

.reader-content-body li {
    margin-bottom: 8px;
    line-height: 1.7;
    text-indent: 0;
}

.reader-content-body hr {
    border: 0;
    height: 1px;
    background: var(--border-color);
    margin: 32px 0;
}

/* Headings */
.reader-content-body h1,
.reader-content-body h2,
.reader-content-body h3,
.reader-content-body h4,
.reader-content-body h5,
.reader-content-body h6 {
    color: var(--text-main);
    font-weight: 700;
    line-height: 1.35;
    margin: 32px 0 16px;
    text-indent: 0 !important;
}

.reader-content-body h1 {
    font-size: 28px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 10px;
}

.reader-content-body h2 {
    font-size: 23px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 8px;
}

.reader-content-body h3 {
    font-size: 19px;
}

.reader-content-body h4 {
    font-size: 17px;
}

/* Markdown Tables */
.reader-table-wrap {
    overflow-x: auto;
    margin: 24px 0;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: var(--bg-surface);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.reader-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14.5px;
    line-height: 1.6;
    text-indent: 0 !important;
}

.reader-table th,
.reader-table td {
    padding: 10px 16px;
    border-bottom: 1px solid var(--border-color);
    border-right: 1px solid var(--border-color);
    vertical-align: top;
    text-indent: 0 !important;
}

.reader-table th:last-child,
.reader-table td:last-child {
    border-right: none;
}

.reader-table tr:last-child td {
    border-bottom: none;
}

.reader-table th {
    background-color: rgba(255, 255, 255, 0.05);
    font-weight: 700;
    color: var(--text-main);
    text-align: left;
}

.reader-table tbody tr:hover {
    background-color: rgba(255, 255, 255, 0.02);
}

/* Links & Images */
.reader-link {
    color: var(--primary);
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 3px;
    transition: color 0.15s ease;
}

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

.reader-img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    margin: 8px 0;
    vertical-align: middle;
}

.reader-content-body p img {
    margin: 4px 6px;
    display: inline-block;
    vertical-align: middle;
}

.reader-content-body p[style*="text-align: center"],
.reader-content-body p.text-center {
    text-indent: 0 !important;
}

.reader-content-body strong,
.reader-content-body b {
    font-weight: 700;
    color: var(--text-main);
}

.reader-content-body em,
.reader-content-body i {
    font-style: italic;
}

.reader-content-body sub,
.reader-content-body sup {
    font-size: 0.8em;
    line-height: 0;
    position: relative;
    vertical-align: baseline;
}
.reader-content-body sub { bottom: -0.25em; }
.reader-content-body sup { top: -0.5em; }

/* Interactive Words */
.reader-word {
    cursor: pointer;
    border-radius: 3px;
    transition: background-color 0.12s ease, color 0.12s ease;
    padding: 1px 2px;
}

.reader-word:hover {
    background-color: var(--primary-dim);
    color: var(--primary);
}

.reader-word.status-mastered.highlight-enabled {
    border-bottom: 2px dotted rgba(16, 185, 129, 0.5);
}

.reader-word.status-learning.highlight-enabled {
    border-bottom: 2px dotted rgba(56, 189, 248, 0.5);
}

/* Click-to-Translate Popup */
.reader-word-popup {
    position: fixed;
    z-index: 10001;
    background-color: var(--bg-surface);
    border: 1px solid var(--border-focus);
    border-radius: var(--radius-lg);
    box-shadow: 0 12px 24px -4px rgba(0, 0, 0, 0.5);
    width: 320px;
    max-width: calc(100vw - 32px);
    padding: 16px;
    animation: fadeInScale 0.15s ease-out;
}

.popup-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border-color);
}

.popup-term-wrap {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.popup-term {
    font-size: 18px;
    color: var(--text-main);
}

.popup-phonetic {
    font-size: 13px;
    color: var(--primary);
    font-family: monospace;
}

.popup-close-btn {
    background: none;
    border: none;
    color: var(--text-dim);
    font-size: 16px;
    cursor: pointer;
    padding: 4px;
}

.popup-close-btn:hover {
    color: var(--text-main);
}

.popup-translation {
    font-size: 15px;
    font-weight: 600;
    color: var(--success);
    margin-bottom: 8px;
}

.popup-context {
    font-size: 12px;
    color: var(--text-muted);
    font-style: italic;
    background: var(--bg-input);
    padding: 8px 10px;
    border-radius: var(--radius-sm);
    margin-bottom: 14px;
    line-height: 1.4;
    border-left: 3px solid var(--primary);
}

.popup-saved-badge {
    text-align: center;
    font-size: 13px;
    font-weight: 600;
    color: var(--success);
    padding: 6px;
}