/* =============================================================================
   Paradise Vocab - CSS Stylesheet
   A classic, literary aesthetic with dark mode default
   ============================================================================= */

/* CSS Custom Properties (Theme Variables) */
:root {
    /* Typography */
    --font-serif: 'EB Garamond', 'Cormorant Garamond', Georgia, serif;
    --font-display: 'Cormorant Garamond', Georgia, serif;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
}

/* Dark Theme (Default) */
[data-theme="dark"] {
    --color-bg: #1a1814;
    --color-bg-elevated: #242019;
    --color-bg-card: #2a251f;
    --color-bg-input: #1e1a15;
    
    --color-text: #e8e4dc;
    --color-text-secondary: #a8a299;
    --color-text-muted: #6b665e;
    
    --color-primary: #c9a962;
    --color-primary-hover: #d9bc78;
    --color-primary-muted: #8b7840;
    
    --color-accent: #7c9885;
    --color-accent-hover: #96b29f;
    
    --color-border: #3d382f;
    --color-border-light: #4a443a;
    
    --color-success: #6b9b6b;
    --color-warning: #c9a962;
    --color-error: #b56b6b;
    
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
}

/* Light Theme */
[data-theme="light"] {
    --color-bg: #f5f2eb;
    --color-bg-elevated: #ffffff;
    --color-bg-card: #fdfcfa;
    --color-bg-input: #f0ede5;
    
    --color-text: #2c2820;
    --color-text-secondary: #5c574d;
    --color-text-muted: #8c8578;
    
    --color-primary: #8b6914;
    --color-primary-hover: #a37d1c;
    --color-primary-muted: #c9a962;
    
    --color-accent: #4a6b52;
    --color-accent-hover: #5a7d62;
    
    --color-border: #ddd8cc;
    --color-border-light: #e8e4da;
    
    --color-success: #4a7c4a;
    --color-warning: #9c7d1a;
    --color-error: #9c4a4a;
    
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.16);
}

/* =============================================================================
   Base Styles
   ============================================================================= */

*, *::before, *::after {
    box-sizing: border-box;
}

html {
    font-size: 18px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-serif);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.7;
    margin: 0;
    padding: 0;
    min-height: 100vh;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 600;
    line-height: 1.3;
    margin: 0 0 var(--spacing-md);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
    margin: 0 0 var(--spacing-md);
}

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

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

em {
    font-style: italic;
}

/* =============================================================================
   Header
   ============================================================================= */

.site-header {
    background-color: var(--color-bg-elevated);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) var(--spacing-xl);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.logo h1 {
    font-size: 1.75rem;
    margin: 0;
    color: var(--color-primary);
    letter-spacing: 0.05em;
}

.logo .tagline {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin: 0;
}

.main-nav {
    display: flex;
    gap: var(--spacing-sm);
}

.nav-btn {
    background: none;
    border: none;
    font-family: var(--font-serif);
    font-size: 1rem;
    color: var(--color-text-secondary);
    padding: var(--spacing-sm) var(--spacing-md);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

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

.nav-btn.active {
    color: var(--color-primary);
    background-color: var(--color-bg-card);
}

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

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

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

.theme-toggle {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    cursor: pointer;
    font-size: 1.25rem;
    line-height: 1;
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    border-color: var(--color-primary);
}

[data-theme="dark"] .theme-toggle .sun { display: none; }
[data-theme="dark"] .theme-toggle .moon { display: inline; }
[data-theme="light"] .theme-toggle .sun { display: inline; }
[data-theme="light"] .theme-toggle .moon { display: none; }

/* =============================================================================
   Main Content
   ============================================================================= */

.main-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-xl);
    min-height: calc(100vh - 200px);
}

.view {
    display: none;
}

.view.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

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

.view-header {
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

.view-header h2 {
    color: var(--color-primary);
}

.view-description {
    color: var(--color-text-secondary);
    font-size: 1.1rem;
}

/* =============================================================================
   Controls (Search, Sort, Filter)
   ============================================================================= */

.controls {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg);
    background-color: var(--color-bg-elevated);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
}

.search-box {
    width: 250px;
    flex-shrink: 0;
}

.search-box input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-family: var(--font-serif);
    font-size: 1rem;
    background-color: var(--color-bg-input);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    transition: border-color var(--transition-fast);
}

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

.search-box input::placeholder {
    color: var(--color-text-muted);
}

.sort-controls, .filter-controls, .toggle-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.sort-controls label, .filter-controls label {
    color: var(--color-text-secondary);
    font-size: 0.9rem;
}

/* Checkbox toggles */
.toggle-controls {
    gap: var(--spacing-md);
}

/* Filter controls grouping */
#vocab-filters, #ref-filters {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    cursor: pointer;
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--color-primary);
    cursor: pointer;
}

.checkbox-label:hover {
    color: var(--color-text);
}

/* Item count */
.item-count {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-md);
    text-align: right;
}

.sort-controls select, .filter-controls select {
    padding: var(--spacing-sm) var(--spacing-md);
    font-family: var(--font-serif);
    font-size: 0.95rem;
    background-color: var(--color-bg-input);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    cursor: pointer;
}

.sort-controls select:focus, .filter-controls select:focus {
    outline: none;
    border-color: var(--color-primary);
}

/* =============================================================================
   Word/Reference List
   ============================================================================= */

.word-list, .reference-list, .library-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.word-card, .ref-card, .library-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.word-card:hover, .ref-card:hover, .library-card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

/* Type badge for combined view */
.type-badge {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    font-size: 0.7rem;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.type-badge.vocab {
    background-color: var(--color-primary-muted);
    color: var(--color-bg);
}

.type-badge.reference {
    background-color: var(--color-accent);
    color: white;
}

.word-card .word-term, .ref-card .ref-name, .library-card .word-term {
    font-size: 1.6rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    font-family: var(--font-display);
}

.word-card .word-pos {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    font-style: italic;
    margin-bottom: var(--spacing-sm);
}

.word-card .word-def, .ref-card .ref-desc {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.word-card .word-meta, .ref-card .ref-meta, .library-card .word-meta {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

.item-type-label {
    text-transform: lowercase;
    font-style: italic;
    color: var(--color-text-muted);
}

.difficulty-stars {
    color: var(--color-primary);
}

.ref-type-badge {
    display: inline-block;
    padding: 2px 8px;
    background-color: var(--color-bg-elevated);
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    text-transform: capitalize;
}

.source-badge {
    color: var(--color-accent);
}

/* =============================================================================
   Flashcards
   ============================================================================= */

.flashcard-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.stat-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    text-align: center;
}

.stat-card .stat-value {
    font-size: 2rem;
    font-weight: 600;
    color: var(--color-primary);
}

.stat-card .stat-label {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
}

.flashcard-controls {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-bg);
    border: none;
    padding: var(--spacing-md) var(--spacing-xl);
    font-family: var(--font-serif);
    font-size: 1rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.btn-secondary {
    background-color: var(--color-bg-card);
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-family: var(--font-serif);
    font-size: 0.9rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-top: var(--spacing-lg);
}

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

.flashcard-container {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.flashcard {
    height: 420px;
    margin-bottom: var(--spacing-xl);
    position: relative;
    overflow: hidden;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    cursor: pointer;
    transition: transform 0.35s ease-out, opacity 0.35s ease-out;
}

/* Swipe out animation */
.flashcard.swiping-out .flashcard-inner {
    transform: translateX(-120%);
    opacity: 0;
}

/* Swipe in animation */
.flashcard.swiping-in .flashcard-inner {
    transform: translateX(120%);
    opacity: 0;
    transition: none;
}

.flashcard-front, .flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    background: linear-gradient(135deg, var(--color-bg-card) 0%, var(--color-bg-elevated) 100%);
    border: 2px solid var(--color-border);
}

/* Hide front when showing back */
.flashcard.showing-back .flashcard-front {
    display: none;
}

.flashcard.showing-back .flashcard-back {
    display: flex;
}

/* Hide back when showing front */
.flashcard:not(.showing-back) .flashcard-back {
    display: none;
}

.flashcard.showing-back .flashcard-front,
.flashcard.showing-back .flashcard-back {
    border-color: var(--color-primary-muted);
}

.flashcard-front .card-type {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--spacing-md);
}

.flashcard-front .card-term {
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--color-primary);
    font-family: var(--font-display);
}

.flashcard-front .card-hint {
    margin-top: var(--spacing-lg);
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

.flashcard-back {
    text-align: left;
    overflow-y: auto;
}

.flashcard-back .card-definition {
    font-size: 1.32rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
    text-align: center;
}

.flashcard-back .card-pos {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    font-style: italic;
    text-align: center;
    margin-bottom: var(--spacing-md);
}

.flashcard-back .card-pl-quote {
    background: var(--color-bg);
    border-left: 3px solid var(--color-primary);
    padding: var(--spacing-sm) var(--spacing-md);
    margin: var(--spacing-md) 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.flashcard-back .quote-text {
    font-style: italic;
    color: var(--color-text);
    font-size: 0.95rem;
    line-height: 1.5;
}

.flashcard-back .quote-ref {
    font-size: 0.8rem;
    color: var(--color-primary);
    margin-top: var(--spacing-xs);
}

.flashcard-back .card-extra {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    margin: var(--spacing-sm) 0;
    line-height: 1.4;
}

.flashcard-back .extra-label,
.flashcard-back .example-label {
    color: var(--color-text-muted);
    font-weight: 600;
}

.flashcard-back .card-example {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    margin-top: var(--spacing-sm);
    line-height: 1.4;
}

.flashcard-back .card-context {
    margin-top: var(--spacing-md);
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

.rating-buttons {
    text-align: center;
}

.rating-buttons p {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.rating-row {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
}

.rating-btn {
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-family: var(--font-serif);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-width: 80px;
}

.rating-btn small {
    display: block;
    font-size: 0.75rem;
    opacity: 0.8;
}

.rating-btn.again {
    background-color: var(--color-error);
    color: white;
}

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

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

.rating-btn.easy {
    background-color: var(--color-success);
    color: white;
}

.rating-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.session-progress {
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* =============================================================================
   About Section
   ============================================================================= */

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-section {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
}

.about-section h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.about-section ul {
    padding-left: var(--spacing-lg);
}

.about-section li {
    margin-bottom: var(--spacing-sm);
}

.about-section.quote {
    text-align: center;
    background: linear-gradient(135deg, var(--color-bg-elevated) 0%, var(--color-bg-card) 100%);
}

.about-section blockquote {
    font-size: 1.3rem;
    font-style: italic;
    color: var(--color-text);
    margin: 0 0 var(--spacing-md);
    line-height: 1.8;
}

.about-section cite {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
}

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

/* =============================================================================
   Modal
   ============================================================================= */

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 1000;
    overflow-y: auto;
    padding: var(--spacing-xl);
}

.modal.active {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    animation: fadeIn 0.2s ease;
}

.modal-content {
    background-color: var(--color-bg-elevated);
    border-radius: var(--radius-lg);
    max-width: 700px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    box-shadow: var(--shadow-lg);
    margin: var(--spacing-xl) 0;
}

.modal-close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--color-text-muted);
    cursor: pointer;
    padding: var(--spacing-sm);
    line-height: 1;
    transition: color var(--transition-fast);
}

.modal-close:hover {
    color: var(--color-text);
}

.modal-body {
    padding: var(--spacing-xl);
}

.modal-body h2 {
    color: var(--color-primary);
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
}

.modal-body .modal-subtitle {
    color: var(--color-text-muted);
    font-style: italic;
    margin-bottom: var(--spacing-lg);
}

.modal-body .definition-block {
    background-color: var(--color-bg-card);
    border-left: 3px solid var(--color-primary);
    padding: var(--spacing-md) var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.modal-body .etymology-block {
    color: var(--color-text-secondary);
    font-style: italic;
    margin-bottom: var(--spacing-lg);
}

.modal-body h3 {
    color: var(--color-text);
    font-size: 1.1rem;
    margin: var(--spacing-lg) 0 var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
    padding-bottom: var(--spacing-sm);
}

.occurrence-item {
    background-color: var(--color-bg-card);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.occurrence-location {
    font-size: 0.85rem;
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.occurrence-text {
    font-style: italic;
    color: var(--color-text-secondary);
}

.occurrence-text .highlight {
    color: var(--color-primary);
    font-weight: 600;
}

/* =============================================================================
   Footer
   ============================================================================= */

.site-footer {
    background-color: var(--color-bg-elevated);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-xl);
    text-align: center;
    color: var(--color-text-muted);
}

.site-footer p {
    margin: var(--spacing-sm) 0;
}

.footer-links a {
    color: var(--color-text-secondary);
}

/* =============================================================================
   Responsive Design
   ============================================================================= */

@media (max-width: 768px) {
    html {
        font-size: 16px;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .main-nav {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .header-actions {
        width: 100%;
        justify-content: center;
    }
    
    .controls {
        flex-direction: column;
    }
    
    .word-list, .reference-list {
        grid-template-columns: 1fr;
    }
    
    .flashcard {
        height: 380px;
        overflow: hidden;
    }
    
    .flashcard-front .card-term {
        font-size: 2rem;
    }
    
    .flashcard-back .card-definition {
        font-size: 1.15rem;
    }
    
    .flashcard-back .quote-text {
        font-size: 0.85rem;
    }
    
    .flashcard.swiping-out .flashcard-inner {
        transform: translateX(-100%);
    }
    
    .flashcard.swiping-in .flashcard-inner {
        transform: translateX(100%);
    }
    
    .rating-row {
        flex-wrap: wrap;
    }
    
    .rating-btn {
        flex: 1;
        min-width: 70px;
    }
}

/* =============================================================================
   Loading States
   ============================================================================= */

.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-2xl);
    color: var(--color-text-muted);
}

.loading::after {
    content: '';
    width: 24px;
    height: 24px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    margin-left: var(--spacing-md);
    animation: spin 1s linear infinite;
}

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

/* =============================================================================
   Empty States
   ============================================================================= */

.empty-state {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--color-text-muted);
}

.empty-state h3 {
    color: var(--color-text-secondary);
}