/* ============================================
   CCFR-201B Study App v4.0 - Styles
   Professional Edition - 160 Questions
   ============================================ */

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

:root {
    --primary-color: #e01e5a;
    --secondary-color: #2c2d30;
    --accent-color: #00a4bd;
    --success-color: #2eb67d;
    --warning-color: #ecb22e;
    --background: #f8f9fa;
    --card-bg: #ffffff;
    --text-primary: #1d1c1d;
    --text-secondary: #616061;
    --border-color: #e0e0e0;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: var(--text-primary);
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    background: var(--background);
    border-radius: 20px;
    padding: 30px;
    box-shadow: var(--shadow-lg);
}

/* ============================================
   HEADER
   ============================================ */

header {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 3px solid var(--primary-color);
}

header h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 10px;
    font-weight: 700;
}

.version {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 600;
}

.author-info {
    margin-top: 15px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.author-info p {
    margin: 5px 0;
}

.author-info a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 600;
}

.author-info a:hover {
    text-decoration: underline;
}

/* ============================================
   STATS BAR
   ============================================ */

.stats-bar {
    display: flex;
    justify-content: space-around;
    gap: 15px;
    margin-bottom: 20px;
    padding: 20px;
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.bookmark-count {
    color: var(--warning-color);
}

/* ============================================
   PROGRESS BAR
   ============================================ */

.progress-container {
    width: 100%;
    height: 10px;
    background: #e0e0e0;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 25px;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-color), var(--success-color));
    width: 0%;
    transition: width 0.5s ease;
}

/* ============================================
   DOMAIN FILTERS
   ============================================ */

.domain-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 30px;
    justify-content: center;
}

.domain-btn {
    padding: 12px 20px;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
}

.domain-btn:hover {
    background: var(--background);
    border-color: var(--accent-color);
    transform: translateY(-2px);
}

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

/* ============================================
   FLASHCARD
   ============================================ */

.flashcard-container {
    position: relative;
    margin-bottom: 30px;
}

.flashcard {
    width: 100%;
    min-height: 500px;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.6s;
    cursor: pointer;
}

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

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    background: var(--card-bg);
    border-radius: 16px;
    padding: 30px;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
}

.card-front {
    background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
}

.card-back {
    transform: rotateY(180deg);
    background: linear-gradient(135deg, #f0f8ff 0%, #e8f5e9 100%);
}

.question-id, .answer-id {
    position: absolute;
    top: 15px;
    left: 20px;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-secondary);
    background: rgba(0, 0, 0, 0.05);
    padding: 5px 10px;
    border-radius: 6px;
}

.domain-badge {
    position: absolute;
    top: 15px;
    right: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    color: white;
    background: var(--accent-color);
    padding: 6px 12px;
    border-radius: 6px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.card-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 30px;
    margin-top: 40px;
}

.language-section {
    flex: 1;
}

.language-section h3 {
    font-size: 1.1rem;
    color: var(--primary-color);
    margin-bottom: 15px;
    font-weight: 700;
}

.question-text, .answer-text {
    font-size: 1.15rem;
    line-height: 1.7;
    color: var(--text-primary);
    font-weight: 500;
}

.answer-text {
    color: var(--success-color);
    font-weight: 600;
}

.language-divider {
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--border-color), transparent);
    margin: 20px 0;
}

.flip-hint {
    text-align: center;
    margin-top: 20px;
    padding: 15px;
    background: rgba(0, 164, 189, 0.1);
    border-radius: 8px;
}

.flip-hint span {
    font-size: 0.85rem;
    color: var(--accent-color);
    font-weight: 600;
}

/* ============================================
   BOOKMARK BUTTON
   ============================================ */

.bookmark-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border: none;
    background: white;
    border-radius: 50%;
    font-size: 1.5rem;
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: var(--transition);
    z-index: 10;
}

.bookmark-btn:hover {
    transform: scale(1.1) rotate(15deg);
}

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

/* ============================================
   CONTROLS
   ============================================ */

.controls {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 30px;
}

.control-btn {
    padding: 15px 30px;
    background: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

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

.flip-btn {
    background: var(--accent-color);
}

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

/* ============================================
   SHORTCUTS INFO
   ============================================ */

.shortcuts-info {
    background: white;
    padding: 20px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.shortcuts-info h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.shortcuts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
}

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

.shortcut kbd {
    background: var(--secondary-color);
    color: white;
    padding: 5px 10px;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.9rem;
    min-width: 70px;
    text-align: center;
}

.shortcut span {
    color: var(--text-secondary);
    font-weight: 500;
}

/* ============================================
   FOOTER
   ============================================ */

footer {
    text-align: center;
    padding-top: 20px;
    border-top: 2px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

footer p {
    margin: 10px 0;
}

footer strong {
    color: var(--primary-color);
}

.disclaimer {
    background: #fff3cd;
    padding: 10px;
    border-radius: 8px;
    border-left: 4px solid var(--warning-color);
    margin: 15px 0;
}

.copyright {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 15px;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 768px) {
    .container {
        padding: 20px;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .stats-bar {
        flex-direction: column;
        gap: 10px;
    }

    .domain-filters {
        flex-direction: column;
    }

    .domain-btn {
        width: 100%;
    }

    .flashcard {
        min-height: 450px;
    }

    .card-content {
        gap: 20px;
    }

    .question-text, .answer-text {
        font-size: 1rem;
    }

    .controls {
        flex-direction: column;
    }

    .control-btn {
        width: 100%;
    }

    .shortcuts-grid {
        grid-template-columns: 1fr;
    }
}

/* ============================================
   ANIMATIONS
   ============================================ */

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.container > * {
    animation: fadeIn 0.6s ease-out;
}

/* ============================================
   PRINT STYLES
   ============================================ */

@media print {
    body {
        background: white;
        padding: 0;
    }

    .controls,
    .shortcuts-info,
    .domain-filters,
    .bookmark-btn {
        display: none;
    }

    .flashcard {
        page-break-inside: avoid;
    }
}