:root {
    /* Light Theme */
    --primary: #DC143C;
    --secondary: #FFFFFF;
    --accent: #C70039;
    --text-primary: #333333;
    --text-secondary: #666666;
    --bg-primary: #FFFFFF;
    --bg-secondary: #F8F8F8;
    --bg-card: #FFFFFF;
    --border: #E0E0E0;
    --shadow: rgba(0, 0, 0, 0.1);
    --success: #28a745;
    --warning: #ffc107;
}

[data-theme="dark"] {
    /* Dark Theme */
    --primary: #DC143C;
    --secondary: #1a1a1a;
    --accent: #FF6B8B;
    --text-primary: #FFFFFF;
    --text-secondary: #CCCCCC;
    --bg-primary: #121212;
    --bg-secondary: #1E1E1E;
    --bg-card: #252525;
    --border: #444444;
    --shadow: rgba(0, 0, 0, 0.3);
    --success: #34D399;
    --warning: #FBBF24;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s, color 0.3s, border-color 0.3s;
}

body {
    font-family: 'Plus Jakarta Sans', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header Styles */
header {
    background-color: var(--bg-primary);
    box-shadow: 0 2px 10px var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 0;
}

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

.logo-icon {
    color: var(--primary);
    font-size: 24px;
}

.logo-text {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary);
}

.logo-image {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-link {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    position: relative;
    padding: 5px 0;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary);
    transition: width 0.3s;
}

.nav-link:hover::after {
    width: 100%;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    font-size: 20px;
    padding: 5px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background-color: var(--bg-secondary);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 24px;
    cursor: pointer;
}

/* Breadcrumb Styles */
.breadcrumb {
    background-color: var(--bg-secondary);
    padding: 15px 0;
    border-bottom: 1px solid var(--border);
}

.breadcrumb-list {
    display: flex;
    align-items: center;
    list-style: none;
    gap: 10px;
    flex-wrap: wrap;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
}

.breadcrumb-item:not(:last-child)::after {
    content: '/';
    color: var(--text-secondary);
    margin-left: 10px;
}

.breadcrumb-item a {
    text-decoration: none;
    color: var(--text-secondary);
    transition: color 0.3s;
    display: flex;
    align-items: center;
    gap: 5px;
}

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

.breadcrumb-item.active span {
    color: var(--primary);
    font-weight: 600;
}

.breadcrumb-item .fas.fa-home {
    font-size: 12px;
}

/* Hero Section */
.hero {
    padding: 40px 0;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

.chapter-header {
    text-align: center;
    margin-bottom: 40px;
}

.chapter-badge {
    display: inline-block;
    background-color: var(--primary);
    color: white;
    padding: 8px 20px;
    border-radius: 20px;
    font-weight: 600;
    margin-bottom: 15px;
}

.chapter-title {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.chapter-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 25px;
}

.chapter-meta {
    display: flex;
    justify-content: center;
    gap: 30px;
    flex-wrap: wrap;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 14px;
}

/* Navigation */
.chapter-nav {
    background-color: var(--bg-card);
    padding: 20px 0;
    border-bottom: 1px solid var(--border);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s;
    border: none;
    font-family: 'Plus Jakarta Sans', sans-serif;
}

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

.btn-primary:hover {
    background-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(220, 20, 60, 0.3);
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.btn-secondary:hover {
    background-color: var(--primary);
    color: white;
    transform: translateY(-2px);
}

.btn-outline {
    background-color: transparent;
    color: var(--text-primary);
    border: 2px solid var(--border);
}

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

/* Section Styles */
.section {
    padding: 60px 0;
}

.section-title {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 30px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 15px;
}

.section-title i {
    color: var(--primary);
}

/* Vocabulary Section */
.vocabulary-section {
    background-color: var(--bg-secondary);
}

.vocabulary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.vocab-card {
    background-color: var(--bg-card);
    border-radius: 10px;
    padding: 25px;
    box-shadow: 0 5px 15px var(--shadow);
    transition: transform 0.3s;
}

.vocab-card:hover {
    transform: translateY(-3px);
}

.vocab-kanji {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--primary);
}

.vocab-reading {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 15px;
    font-family: monospace;
}

.vocab-meaning {
    font-size: 16px;
    color: var(--text-primary);
    margin-bottom: 15px;
}

.vocab-indonesia {
    font-size: 14px;
    color: var(--text-secondary);
    font-style: italic;
    border-left: 3px solid var(--primary);
    padding-left: 15px;
}

/* Grammar Section */
.grammar-section {
    background-color: var(--bg-primary);
}

.grammar-item {
    background-color: var(--bg-card);
    border-radius: 10px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 5px 15px var(--shadow);
}

.grammar-pattern {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--primary);
}

.grammar-explanation {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.8;
}

.grammar-examples {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: 20px;
}

.example-item {
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border);
}

.example-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.example-japanese {
    font-size: 16px;
    margin-bottom: 5px;
}

.example-reading {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 5px;
    font-family: monospace;
}

.example-meaning {
    font-size: 14px;
    color: var(--text-secondary);
}

/* Conversation Section */
.conversation-section {
    background-color: var(--bg-secondary);
}

.conversation-card {
    background-color: var(--bg-card);
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 5px 15px var(--shadow);
    max-width: 800px;
    margin: 0 auto;
}

.dialogue-item {
    margin-bottom: 25px;
    padding: 20px;
    background-color: var(--bg-secondary);
    border-radius: 8px;
}

.speaker {
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.dialogue-text {
    margin-bottom: 10px;
    line-height: 1.6;
}

.dialogue-reading {
    font-size: 14px;
    color: var(--text-secondary);
    font-family: monospace;
    margin-bottom: 10px;
}

.dialogue-meaning {
    font-size: 14px;
    color: var(--text-secondary);
    font-style: italic;
}

/* Reference Section */
.reference-section {
    background-color: var(--bg-primary);
    padding: 60px 0;
}

.reference-content {
    margin-bottom: 40px;
}

.reference-content h3 {
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 20px;
    border-left: 4px solid var(--primary-color);
}

.reference-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

.reference-item {
    background: var(--bg-secondary);
    padding: 15px;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    border: 1px solid var(--border-color);
}

.reference-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.reference-japanese {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.reference-reading {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-style: italic;
}

/* Info Box Styles */
.info-box {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    border: 1px solid var(--border-color);
}

.info-title {
    display: flex;
    align-items: center;
    margin-bottom: 15px;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 1.1rem;
}

.info-title i {
    margin-right: 10px;
    font-size: 1.2rem;
}

.info-content {
    padding-left: 10px;
}

.info-japanese {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.info-reading {
    font-size: 0.95rem;
    color: var(--text-secondary);
    font-style: italic;
    margin-bottom: 5px;
}

.info-meaning {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 10px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .reference-grid {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
        gap: 10px;
    }
    
    .reference-item {
        padding: 12px 8px;
    }
    
    .reference-japanese {
        font-size: 1.1rem;
    }
    
    .info-box {
        padding: 15px;
    }
}

@media (max-width: 480px) {
    .reference-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .reference-section {
        padding: 40px 0;
    }
}

/* Practice Section */
.practice-section {
    background-color: var(--bg-secondary);
}

.practice-card {
    background-color: var(--bg-card);
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 5px 15px var(--shadow);
    margin-bottom: 30px;
}

.practice-question {
    font-size: 18px;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.practice-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.practice-option {
    padding: 15px;
    border: 2px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    text-align: center;
}

.practice-option:hover {
    border-color: var(--primary);
}

.practice-option.selected {
    background-color: var(--primary);
    color: white;
    border-color: var(--primary);
}

.practice-feedback {
    padding: 15px;
    border-radius: 8px;
    margin-top: 15px;
    display: none;
}

.practice-feedback.correct {
    background-color: rgba(40, 167, 69, 0.1);
    color: var(--success);
    border: 1px solid var(--success);
    display: block;
}

.practice-feedback.incorrect {
    background-color: rgba(220, 20, 60, 0.1);
    color: var(--primary);
    border: 1px solid var(--primary);
    display: block;
}

/* Resources Section */
.resources-section {
    background-color: var(--bg-primary);
    text-align: center;
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.resource-card {
    background-color: var(--bg-card);
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 5px 15px var(--shadow);
    text-align: center;
    transition: transform 0.3s;
}

.resource-card:hover {
    transform: translateY(-5px);
}

.resource-icon {
    width: 60px;
    height: 60px;
    background-color: rgba(220, 20, 60, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    color: var(--primary);
    font-size: 24px;
}

.resource-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.resource-description {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 14px;
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-column h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    text-decoration: none;
    color: var(--text-secondary);
    transition: color 0.3s;
}

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

.social-links {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.social-link {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--bg-card);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    text-decoration: none;
    transition: all 0.3s;
}

.social-link:hover {
    background-color: var(--primary);
    color: white;
    transform: translateY(-3px);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 14px;
}

/* Go to Top Button */
.go-to-top-btn {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: var(--primary);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    transition: all 0.3s ease;
    z-index: 1000;
}

.go-to-top-btn:hover {
    background-color: var(--accent);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

.go-to-top-btn.show {
    display: flex;
}

/* Responsive Styles */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--bg-primary);
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 5px 10px var(--shadow);
        gap: 15px;
    }

    .nav-menu.active {
        display: flex;
    }

    .mobile-menu-toggle {
        display: block;
    }

    .chapter-title {
        font-size: 28px;
    }

    .section-title {
        font-size: 24px;
    }

    .nav-container {
        gap: 10px;
    }

    .breadcrumb {
        padding: 10px 0;
    }
    
    .breadcrumb-list {
        gap: 5px;
    }
    
    .breadcrumb-item {
        font-size: 12px;
    }

    .go-to-top-btn {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
        font-size: 16px;
    }
}

@media (max-width: 576px) {
    .vocabulary-grid {
        grid-template-columns: 1fr;
    }

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

    .practice-options {
        grid-template-columns: 1fr;
    }

    .breadcrumb-list {
        overflow-x: auto;
        white-space: nowrap;
        flex-wrap: nowrap;
        padding-bottom: 5px;
        -webkit-overflow-scrolling: touch;
    }
    
    .breadcrumb-item {
        flex-shrink: 0;
    }
}