/* AP Guides Hub - Shared Styles */
/* Reset and Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Light theme */
    --bg-gradient-start: #667eea;
    --bg-gradient-end: #764ba2;
    --bg-container: rgba(255, 255, 255, 0.95);
    --bg-controls: #f8f9fa;
    --bg-card: white;
    --bg-stats: #e3f2fd;
    --border-color: #e9ecef;
    --text-primary: #2c3e50;
    --text-secondary: #4a5568;
    --text-muted: #6c757d;
    --text-stats: #1976d2;
    --accent-color: #3498db;
    --shadow-light: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-heavy: 0 8px 15px rgba(0, 0, 0, 0.2);
    --shadow-container: 0 20px 40px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    /* Dark theme */
    --bg-gradient-start: #1a1a2e;
    --bg-gradient-end: #16213e;
    --bg-container: rgba(30, 30, 46, 0.95);
    --bg-controls: #2a2a3e;
    --bg-card: #353548;
    --bg-stats: #2a3f5f;
    --border-color: #4a4a5e;
    --text-primary: #e2e8f0;
    --text-secondary: #cbd5e0;
    --text-muted: #a0aec0;
    --text-stats: #81c1f5;
    --accent-color: #4facfe;
    --shadow-light: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-heavy: 0 8px 15px rgba(0, 0, 0, 0.4);
    --shadow-container: 0 20px 40px rgba(0, 0, 0, 0.3);
}

/* Body and Main Container */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    min-height: 100vh;
    padding: 20px;
    transition: all 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--bg-container);
    border-radius: 15px;
    box-shadow: var(--shadow-container);
    overflow: hidden;
    transition: all 0.3s ease;
}

/* Header Styles */
.header {
    background: linear-gradient(135deg, var(--bg-gradient-start), var(--accent-color));
    color: white;
    padding: 40px 30px;
    text-align: center;
    position: relative;
}

.header h1 {
    font-size: 2.8rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.header p {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Theme Toggle */
.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 25px;
    padding: 10px 15px;
    color: white;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* Controls Section */
.controls {
    padding: 30px;
    background: var(--bg-controls);
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.controls-row {
    display: flex;
    gap: 20px;
    align-items: center;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.controls-row:last-child {
    margin-bottom: 0;
}

/* Search Box */
.search-container {
    flex: 1;
    min-width: 300px;
}

.search-box {
    position: relative;
}

.search-box input {
    width: 100%;
    padding: 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 16px;
    background: var(--bg-card);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

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

/* Filter Groups */
.filter-group {
    display: flex;
    gap: 10px;
    align-items: center;
}

.filter-group label {
    font-weight: 600;
    color: var(--text-primary);
    min-width: 60px;
}

.filter-group select {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    background: var(--bg-card);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 140px;
}

.filter-group select:focus {
    outline: none;
    border-color: var(--accent-color);
}

/* Mode Buttons */
.mode-buttons {
    display: flex;
    gap: 10px;
}

.mode-btn {
    padding: 12px 20px;
    border: 2px solid var(--accent-color);
    border-radius: 10px;
    background: var(--bg-card);
    color: var(--accent-color);
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.mode-btn:hover,
.mode-btn.active {
    background: var(--accent-color);
    color: white;
    transform: translateY(-1px);
}

/* Stats Bar */
.stats {
    background: var(--bg-stats);
    padding: 15px 30px;
    font-weight: 600;
    color: var(--text-stats);
    transition: all 0.3s ease;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.shuffle-btn {
    padding: 8px 16px;
    border: 1px solid var(--text-stats);
    border-radius: 6px;
    background: transparent;
    color: var(--text-stats);
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s ease;
}

.shuffle-btn:hover {
    background: var(--text-stats);
    color: white;
}

/* Terms Grid */
.terms-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(380px, 1fr));
    gap: 25px;
    padding: 30px;
}

/* Term Cards */
.term-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 25px;
    box-shadow: var(--shadow-light);
    border-left: 4px solid var(--accent-color);
    transition: all 0.3s ease;
    position: relative;
}

.term-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-heavy);
}

.term-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
}

.term-name {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
    margin-right: 15px;
    flex: 1;
}

.term-definition {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.7;
}

/* Unit Badges */
.unit-badge {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--bg-gradient-end) 100%);
    color: white;
    font-size: 0.9rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.15);
    flex-shrink: 0;
    position: relative;
    transition: all 0.3s ease;
}

.unit-badge::before {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    right: 2px;
    bottom: 2px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.term-card:hover .unit-badge::before {
    opacity: 1;
}


/* Enhanced Footer Styles */
.enhanced-footer {
    background: linear-gradient(135deg, var(--bg-gradient-start), var(--accent-color));
    color: white;
    padding: 40px 30px 25px;
    position: relative;
    overflow: hidden;
    margin-top: 40px;
}

.enhanced-footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
}

.footer-content {
    max-width: 1000px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 40px;
    align-items: start;
}

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

.footer-section h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.disclaimer-text {
    font-size: 0.95rem;
    line-height: 1.6;
    opacity: 0.9;
    background: rgba(255, 255, 255, 0.1);
    padding: 20px;
    border-radius: 12px;
    border-left: 3px solid rgba(255, 255, 255, 0.3);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: center;
}

.footer-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
    font-size: 0.95rem;
}

.footer-link:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
    text-decoration: none;
}

.footer-emoji {
    font-size: 1.1em;
}

.paypal-note {
    font-size: 0.85rem;
    opacity: 0.8;
    margin-top: 8px;
    font-style: italic;
}

.copyright-text {
    font-size: 0.9rem;
    line-height: 1.6;
    opacity: 0.9;
    background: rgba(255, 255, 255, 0.08);
    padding: 18px;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

/* Footer Responsive Design */
@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .enhanced-footer {
        padding: 30px 20px 20px;
    }

    .disclaimer-text {
        font-size: 0.9rem;
        padding: 16px;
    }

    .footer-section h4 {
        font-size: 1rem;
    }
}


[data-theme="dark"] .unit-badge {
    background: linear-gradient(135deg, var(--accent-color) 0%, #4a4a5e 100%);
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.3);
}

/* Flashcard Mode Styles */
.flashcard-mode .term-card {
    min-height: 220px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
    cursor: pointer;
    user-select: none;
}

.flashcard-mode .term-card:hover {
    transform: translateY(-5px) scale(1.02);
}

.flashcard-mode .term-name {
    font-size: 1.5rem;
    text-align: center;
    margin-right: 0;
}

.flashcard-mode .term-definition {
    font-size: 1.1rem;
    text-align: center;
    margin-top: 10px;
}

.flashcard-mode .term-card:not(.flipped) .term-definition {
    display: none;
}

.flashcard-mode .term-card.flipped .term-header {
    display: none;
}

.flashcard-mode .term-card.flipped .term-definition {
    display: block;
}

.flip-indicator {
    position: absolute;
    bottom: 15px;
    right: 15px;
    font-size: 12px;
    color: var(--text-muted);
    opacity: 0.7;
}

.flashcard-mode .flip-indicator {
    position: static;
    margin-top: 15px;
    font-style: italic;
}

/* No Results State */
.no-results {
    text-align: center;
    padding: 80px 30px;
    color: var(--text-muted);
}

.no-results h3 {
    font-size: 1.8rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.no-results p {
    font-size: 1.1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 15px;
    }

    .header {
        padding: 30px 20px;
    }

    .header h1 {
        font-size: 2.2rem;
    }

    .header p {
        font-size: 1rem;
    }

    .theme-toggle {
        position: static;
        margin-top: 20px;
    }

    .controls {
        padding: 20px;
    }

    .controls-row {
        flex-direction: column;
        align-items: stretch;
        margin-bottom: 15px;
    }

    .search-container {
        min-width: unset;
    }

    .filter-group {
        justify-content: space-between;
    }

    .filter-group select {
        min-width: unset;
        flex: 1;
    }

    .mode-buttons {
        justify-content: center;
    }

    .mode-btn {
        flex: 1;
        text-align: center;
    }

    .stats {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }

    .terms-grid {
        grid-template-columns: 1fr;
        padding: 20px;
        gap: 20px;
    }

    .term-card {
        padding: 20px;
    }

    .term-name {
        font-size: 1.2rem;
        margin-right: 10px;
    }

    .term-definition {
        font-size: 0.95rem;
    }

    .unit-badge {
        width: 32px;
        height: 32px;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .header h1 {
        font-size: 1.8rem;
    }

    .term-card {
        padding: 15px;
    }

    .terms-grid {
        padding: 15px;
        gap: 15px;
    }

    .unit-badge {
        width: 28px;
        height: 28px;
        font-size: 0.8rem;
    }
}

/* Smooth Transitions */
* {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

/* Focus and Accessibility */
button:focus,
select:focus,
input:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    .header,
    .controls,
    .stats {
        display: none;
    }
    
    .term-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ddd;
        margin-bottom: 15px;
    }
    
    .terms-grid {
        display: block;
    }
}

/* Animation Classes */
.fade-in {
    animation: fadeIn 0.3s ease-in;
}

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

.slide-in {
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from { transform: translateX(-20px); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

/* Loading States */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* Special Subject Color Variants */
.subject-statistics { --accent-color: #e74c3c; }
.subject-calculus { --accent-color: #f39c12; }
.subject-physics { --accent-color: #9b59b6; }
.subject-chemistry { --accent-color: #27ae60; }
.subject-biology { --accent-color: #16a085; }
.subject-psychology { --accent-color: #e67e22; }
.subject-history { --accent-color: #8e44ad; }
.subject-english { --accent-color: #34495e; }
.subject-csp { --accent-color: #3498db; }

/* Additional Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }

.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.font-medium { font-weight: 500; }

.hidden { display: none; }
.visible { display: block; }