:root {
    --bg-color: #f4f7f6;
    --text-color: #2c3e50;
    --card-bg: #ffffff;
    --primary-color: #3498db;
    --border-color: #e0e0e0;
    --correct-bg: #d4edda;
    --correct-border: #c3e6cb;
    --wrong-bg: #f8d7da;
    --wrong-border: #f5c6cb;
    --secondary-color: #2ecc71;
    --hover-color: #2980b9;
}

[data-theme="dark"] {
    --bg-color: #1a1a2e;
    --text-color: #e6e6e6;
    --card-bg: #16213e;
    --primary-color: #e94560;
    --border-color: #2a2a4a;
    --correct-bg: #1e4620;
    --correct-border: #28a745;
    --wrong-bg: #5a1e20;
    --wrong-border: #dc3545;
    --secondary-color: #4cd137;
    --hover-color: #c81e45;
}

[data-theme="green"] {
    --bg-color: #e8f5e9;
    --text-color: #1b5e20;
    --card-bg: #ffffff;
    --primary-color: #43a047;
    --border-color: #c8e6c9;
    --correct-bg: #d4edda;
    --correct-border: #c3e6cb;
    --wrong-bg: #f8d7da;
    --wrong-border: #f5c6cb;
    --secondary-color: #2e7d32;
    --hover-color: #2e7d32;
}

[data-theme="blue"] {
    --bg-color: #e3f2fd;
    --text-color: #0d47a1;
    --card-bg: #ffffff;
    --primary-color: #1e88e5;
    --border-color: #bbdefb;
    --correct-bg: #d4edda;
    --correct-border: #c3e6cb;
    --wrong-bg: #f8d7da;
    --wrong-border: #f5c6cb;
    --secondary-color: #1565c0;
    --hover-color: #1565c0;
}

[data-theme="melon"] {
    --bg-color: #fff8e1;
    --text-color: #e65100;
    --card-bg: #ffffff;
    --primary-color: #fb8c00;
    --border-color: #ffe082;
    --correct-bg: #d4edda;
    --correct-border: #c3e6cb;
    --wrong-bg: #f8d7da;
    --wrong-border: #f5c6cb;
    --secondary-color: #f57c00;
    --hover-color: #f57c00;
}

[data-theme="pink"] {
    --bg-color: #fce4ec;
    --text-color: #880e4f;
    --card-bg: #ffffff;
    --primary-color: #d81b60;
    --border-color: #f8bbd0;
    --correct-bg: #d4edda;
    --correct-border: #c3e6cb;
    --wrong-bg: #ffcdd2;
    --wrong-border: #ef9a9a;
    --secondary-color: #c2185b;
    --hover-color: #c2185b;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    transition: all 0.3s ease;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 40px;
    background-color: var(--card-bg);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.theme-switch-wrapper {
    display: flex;
    align-items: center;
}

.theme-select {
    padding: 8px 12px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-color);
    font-size: 1rem;
    font-family: inherit;
    cursor: pointer;
    transition: border-color 0.2s;
}

.theme-select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.container {
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
}

/* SPA NAVIGATION STYLES */
.menu-title {
    text-align: center;
    font-size: 2em;
    margin-bottom: 40px;
    color: var(--primary-color);
}

.menu-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.menu-card {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.menu-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 25px rgba(0,0,0,0.1);
}

.menu-card-header {
    margin-bottom: 20px;
}

.subject-tag {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.85em;
    font-weight: bold;
    margin-bottom: 10px;
}

.menu-card-header h3 {
    margin: 0;
    font-size: 1.4em;
    color: var(--text-color);
}

.menu-card-actions {
    display: flex;
    gap: 10px;
}

.action-btn {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: bold;
    font-size: 1rem;
    transition: background-color 0.2s, color 0.2s;
}

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

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

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

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

.back-btn {
    background-color: transparent;
    border: none;
    color: var(--text-color);
    font-size: 1.1em;
    cursor: pointer;
    margin-bottom: 30px;
    display: inline-flex;
    align-items: center;
    padding: 10px 15px;
    border-radius: 6px;
    transition: background-color 0.2s;
    text-decoration: underline;
}

.back-btn:hover {
    background-color: rgba(0,0,0,0.05);
}

.detail-card {
    background-color: var(--card-bg);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    border: 1px solid var(--border-color);
}

.content-body {
    line-height: 1.8;
    font-size: 1.1em;
}

.content-body h3, .content-body h4 {
    color: var(--primary-color);
    margin-top: 30px;
}

.detail-actions {
    margin-top: 40px;
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
    text-align: right;
}

.quiz-detail {
    max-width: 800px;
    margin: 0 auto;
}

/* OLD STYLES (Kept for compatibility) */
.subject-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    margin-bottom: 50px;
    background-color: var(--card-bg);
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

h2 {
    color: var(--primary-color);
    margin-top: 0;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
}

.question-block {
    margin-bottom: 20px;
    padding: 15px;
    background: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.options-list {
    list-style: none;
    padding: 0;
}

.options-list li {
    margin: 10px 0;
}

.options-list label {
    display: block;
    padding: 10px;
    background: var(--bg-color);
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.2s;
    border: 1px solid var(--border-color);
}

.options-list label:hover {
    background: var(--border-color);
}

.finish-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 16px;
    cursor: pointer;
    border-radius: 6px;
    margin-top: 20px;
    width: 100%;
    transition: opacity 0.2s;
}

.finish-btn:hover {
    opacity: 0.9;
}

.result-box {
    margin-top: 20px;
    padding: 15px;
    border-radius: 8px;
    font-size: 18px;
    font-weight: bold;
    text-align: center;
}

.correct-option {
    background-color: var(--correct-bg) !important;
    border-color: var(--correct-border) !important;
}

.wrong-option {
    background-color: var(--wrong-bg) !important;
    border-color: var(--wrong-border) !important;
}

.question-image {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 15px 0;
    max-height: 300px;
    object-fit: contain;
    display: block;
}

.header-left {
    display: flex;
    flex-direction: column;
}

.org-name {
    font-size: 0.9em;
    color: var(--primary-color);
    font-weight: bold;
    text-transform: uppercase;
    margin-bottom: 5px;
    letter-spacing: 1px;
}

.quiz-topic {
    color: var(--text-color);
    margin: 0;
    font-size: 1.8em;
    border: none;
    padding: 0;
}

.footer {
    text-align: center;
    padding: 20px;
    background-color: var(--card-bg);
    border-top: 1px solid var(--border-color);
    margin-top: 50px;
    color: var(--text-color);
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.05);
}

@media (max-width: 768px) {
    .header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    .menu-grid {
        grid-template-columns: 1fr;
    }
    .menu-card-actions {
        flex-direction: column;
    }
}