:root {
    --primary-color: #2c5b8a;
    --secondary-color: #1a3c5a;
    --background-color: #f0f2f5;
    --card-background: #ffffff;
    --text-color: #333;
    --light-text-color: #ffffff;
    --border-color: #e0e6ec;
    --shadow-color: rgba(0, 0, 0, 0.08);
    --success-color: #28a745;
    --danger-color: #dc3545;
    --info-bg-color: #eef7ff;
}

body {
    font-family: 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--light-text-color);
    padding: 25px 30px;
    border-radius: 12px;
    text-align: center;
    margin-bottom: 25px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

header h1 {
    margin: 0;
    font-size: 2.2em;
}

nav#module-selection {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
    margin-bottom: 30px;
}

.module-btn {
    background-color: var(--card-background);
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
    padding: 10px 20px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.95em;
    font-weight: 500;
    transition: all 0.3s ease;
}

.module-btn:hover, .module-btn.active {
    background-color: var(--primary-color);
    color: var(--light-text-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-color);
}

#case-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 25px;
}

.case-card {
    background-color: var(--card-background);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 5px var(--shadow-color);
    transition: all 0.3s ease;
    cursor: pointer;
    display: flex;
    flex-direction: column;
}

.case-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px var(--shadow-color);
}

.case-card h3 {
    margin: 0 0 10px 0;
    color: var(--secondary-color);
    font-size: 1.25em;
}

.case-card p {
    flex-grow: 1;
    color: #666;
    font-size: 0.9em;
}

.case-card-footer {
    font-size: 0.8em;
    color: #999;
    text-align: right;
    border-top: 1px solid var(--border-color);
    padding-top: 10px;
    margin-top: 15px;
}

/* Modal Styles */
.modal {
    display: none; position: fixed; z-index: 1000;
    left: 0; top: 0; width: 100%; height: 100%;
    overflow: auto; background-color: rgba(0,0,0,0.7);
    animation: fadeIn 0.3s;
}

.modal-content {
    background-color: #fefefe;
    margin: 3% auto;
    padding: 25px;
    border: 1px solid #888;
    width: 90%;
    max-width: 1100px;
    border-radius: 12px;
    box-shadow: 0 5px 25px rgba(0,0,0,0.3);
    position: relative;
}

.close-btn {
    color: #aaa; position: absolute; top: 10px; right: 20px;
    font-size: 30px; font-weight: bold; cursor: pointer;
}
.close-btn:hover { color: #000; }

#modal-body h2 {
    color: var(--secondary-color);
    margin-top: 0;
}

.case-detail-layout {
    display: flex;
    gap: 25px;
}

.left-panel {
    flex: 1;
    min-width: 0;
}

.right-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 15px;
    min-width: 0;
}

.image-gallery {
    display: flex; flex-direction: column; gap: 10px;
    background: var(--background-color); padding: 15px;
    border-radius: 8px; border: 1px solid var(--border-color);
    max-height: 75vh; overflow-y: auto;
}
.image-gallery img {
    width: 100%; height: auto; border: 2px solid var(--border-color);
    border-radius: 4px; cursor: zoom-in;
}

.info-section {
    background-color: var(--info-bg-color);
    padding: 15px; border-radius: 8px; border: 1px solid #cce5ff;
}
.info-section h4 { margin: 0 0 10px 0; color: var(--primary-color); }

.quiz-section h4 { margin: 0 0 15px 0; color: var(--secondary-color); }
.options-grid {
    display: grid; grid-template-columns: 1fr; gap: 10px;
}
.option-btn {
    width: 100%; padding: 12px; text-align: left;
    background-color: #fff; border: 1px solid var(--border-color);
    border-radius: 5px; cursor: pointer; transition: all 0.2s;
    font-size: 1em;
}
.option-btn:hover:not(:disabled) {
    background-color: var(--info-bg-color);
    border-color: var(--primary-color);
}
.option-btn.correct { background-color: #d4edda; border-color: var(--success-color); color: #155724; font-weight: bold; }
.option-btn.incorrect { background-color: #f8d7da; border-color: var(--danger-color); color: #721c24; }
.option-btn:disabled { cursor: not-allowed; opacity: 0.8; }

.analysis-section {
    display: none;
    margin-top: 20px; padding: 20px;
    background-color: #f8f9fa; border: 1px solid var(--border-color);
    border-radius: 8px; animation: slideDown 0.5s;
    max-height: 40vh; overflow-y: auto;
}
.analysis-section strong {
    color: var(--secondary-color); display: block;
    margin-top: 10px; margin-bottom: 5px;
}
@keyframes slideDown {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Image Zoom Modal */
.zoom-modal { display: none; position: fixed; z-index: 1001; padding: 20px;
    left: 0; top: 0; width: 100%; height: 100%;
    overflow: auto; background-color: rgba(0,0,0,0.9);
}
.zoom-modal-content { margin: auto; display: block; max-width: 95%; max-height: 95%; }
.zoom-close { position: absolute; top: 15px; right: 35px; color: #f1f1f1;
    font-size: 40px; font-weight: bold; transition: 0.3s; cursor: pointer;
}
.zoom-modal-content, .zoom-close { animation: zoom 0.5s; }
@keyframes zoom { from {transform:scale(0)} to {transform:scale(1)} }

@media (max-width: 768px) {
    .case-detail-layout { flex-direction: column; }
    .modal-content { margin: 10% auto; }
}