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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary-color: #f97316;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
}

#app {
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-lg);
    z-index: 100;
}

.header-left .logo {
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.user-info {
    display: flex;
    gap: 1.5rem;
}

.user-info > div {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.95rem;
}

.settings-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.settings-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: rotate(90deg);
}

/* Main Container */
.main-container {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: 300px;
    background: var(--card-bg);
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    flex-shrink: 0;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    background: #f1f5f9;
}

.sidebar-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.level-nav {
    padding: 1rem 0;
}

.level-item {
    padding: 1rem 1.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    transition: all 0.3s ease;
    border-left: 3px solid transparent;
}

.level-item:hover {
    background: #f8fafc;
}

.level-item.active {
    background: #eff6ff;
    border-left-color: var(--primary-color);
    color: var(--primary-color);
}

.level-item.locked {
    color: var(--text-secondary);
    opacity: 0.6;
    cursor: not-allowed;
}

.level-item.locked:hover {
    background: transparent;
}

.level-icon {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    background: var(--primary-color);
    color: white;
}

.level-item.completed .level-icon {
    background: var(--success-color);
}

.level-item.locked .level-icon {
    background: var(--text-secondary);
}

.level-info {
    flex: 1;
}

.level-title {
    font-weight: 500;
    font-size: 0.95rem;
}

.level-progress {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* Content */
.content {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
}

/* Welcome Page */
.welcome-page {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
}

.welcome-content {
    text-align: center;
    max-width: 600px;
}

.welcome-icon {
    font-size: 6rem;
    color: var(--primary-color);
    margin-bottom: 2rem;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

.welcome-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.welcome-content p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.start-btn {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    border: none;
    padding: 1rem 3rem;
    font-size: 1.2rem;
    font-weight: 600;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-lg);
}

.start-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
}

/* Level Page */
.level-header {
    margin-bottom: 2rem;
}

.level-header h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.level-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.knowledge-map {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.knowledge-map h3 {
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.map-nodes {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.map-node {
    padding: 0.75rem 1.5rem;
    background: #f1f5f9;
    border-radius: 8px;
    font-size: 0.95rem;
}

.sub-levels {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.sub-level-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.sub-level-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.sub-level-card.locked {
    opacity: 0.6;
    cursor: not-allowed;
}

.sub-level-card.locked:hover {
    transform: none;
    border-color: transparent;
}

.sub-level-card.completed {
    border-color: var(--success-color);
}

.sub-level-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.sub-level-number {
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

.sub-level-card.completed .sub-level-number {
    background: var(--success-color);
}

.sub-level-card.locked .sub-level-number {
    background: var(--text-secondary);
}

.sub-level-stars {
    color: var(--warning-color);
    font-size: 1.2rem;
}

.sub-level-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.sub-level-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Study Page */
.study-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.back-btn {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
}

.back-btn:hover {
    background: #e2e8f0;
}

.study-content {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
    min-height: 400px;
}

.knowledge-card {
    animation: fadeIn 0.5s ease;
}

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

.knowledge-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.knowledge-text {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.knowledge-point {
    background: #f8fafc;
    padding: 1rem 1.5rem;
    border-left: 4px solid var(--primary-color);
    margin: 1rem 0;
    border-radius: 0 8px 8px 0;
}

.knowledge-point h4 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.study-nav {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
}

/* Quiz Page */
.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.quiz-progress {
    font-size: 1.2rem;
    font-weight: 600;
}

.quiz-stars {
    font-size: 1.5rem;
    color: var(--warning-color);
}

.question-container {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.question-text {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    line-height: 1.6;
}

.options-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.option-item {
    padding: 1rem 1.5rem;
    background: #f8fafc;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.option-item:hover {
    border-color: var(--primary-color);
    background: #eff6ff;
}

.option-item.selected {
    border-color: var(--primary-color);
    background: #eff6ff;
}

.option-item.correct {
    border-color: var(--success-color);
    background: #d1fae5;
}

.option-item.incorrect {
    border-color: var(--danger-color);
    background: #fee2e2;
}

.option-letter {
    width: 32px;
    height: 32px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    flex-shrink: 0;
}

.option-item.correct .option-letter {
    background: var(--success-color);
}

.option-item.incorrect .option-letter {
    background: var(--danger-color);
}

.option-text {
    flex: 1;
}

.explanation {
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: #fffbeb;
    border-left: 4px solid var(--warning-color);
    border-radius: 0 8px 8px 0;
}

.explanation h4 {
    margin-bottom: 0.5rem;
    color: var(--warning-color);
}

.quiz-nav {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
}

/* Result Page */
.result-page {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
}

.result-content {
    text-align: center;
    background: var(--card-bg);
    padding: 3rem;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    max-width: 500px;
}

.result-icon {
    font-size: 5rem;
    color: var(--warning-color);
    margin-bottom: 1.5rem;
    animation: bounce 1s ease infinite;
}

@keyframes bounce {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.result-content h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.result-stars {
    font-size: 3rem;
    color: var(--warning-color);
    margin-bottom: 1.5rem;
}

.result-stats {
    margin-bottom: 2rem;
}

.result-stats p {
    font-size: 1.2rem;
    margin: 0.5rem 0;
}

.result-stats span {
    font-weight: 700;
    color: var(--primary-color);
}

.result-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* Achievement Page */
.achievement-header {
    margin-bottom: 2rem;
}

.achievement-header h2 {
    font-size: 2rem;
}

.achievement-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-card i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.stat-card h3 {
    font-size: 2rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.stat-card p {
    color: var(--text-secondary);
}

.medals-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 1.5rem;
}

.medal-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-align: center;
    transition: all 0.3s ease;
}

.medal-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.medal-card.locked {
    opacity: 0.5;
}

.medal-card-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.medal-card.unlocked .medal-card-icon {
    color: var(--warning-color);
}

.medal-card.locked .medal-card-icon {
    color: var(--text-secondary);
}

.medal-card h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.medal-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Settings Page */
.settings-header {
    margin-bottom: 2rem;
}

.settings-header h2 {
    font-size: 2rem;
}

.settings-content {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.setting-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.setting-item:last-child {
    border-bottom: none;
}

.setting-item label {
    font-size: 1.1rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.setting-item select {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
}

.toggle-switch {
    width: 60px;
    height: 32px;
    background: var(--text-secondary);
    border-radius: 16px;
    cursor: pointer;
    position: relative;
    transition: all 0.3s ease;
}

.toggle-switch.active {
    background: var(--primary-color);
}

.toggle-btn {
    width: 28px;
    height: 28px;
    background: white;
    border-radius: 50%;
    position: absolute;
    top: 2px;
    left: 2px;
    transition: all 0.3s ease;
}

.toggle-switch.active .toggle-btn {
    left: 30px;
}

/* Footer */
.footer {
    background: var(--card-bg);
    padding: 1rem 2rem;
    border-top: 1px solid var(--border-color);
}

.progress-container {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.progress-label {
    font-weight: 500;
    min-width: 80px;
}

.progress-bar {
    flex: 1;
    height: 12px;
    background: var(--border-color);
    border-radius: 6px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border-radius: 6px;
    transition: width 0.5s ease;
}

.progress-text {
    font-weight: 600;
    min-width: 50px;
    text-align: right;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-dark);
}

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

.btn-success:hover:not(:disabled) {
    background: #059669;
}

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

.btn-secondary:hover:not(:disabled) {
    background: #475569;
}

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

.btn-warning:hover:not(:disabled) {
    background: #d97706;
}

/* Modals */
.level-up-modal,
.medal-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.level-up-modal .modal-content,
.medal-modal .modal-content {
    background: white;
    padding: 3rem;
    border-radius: 16px;
    text-align: center;
    max-width: 400px;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from { transform: translateY(50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.modal-icon {
    font-size: 4rem;
    color: var(--warning-color);
    margin-bottom: 1rem;
}

.medal-icon {
    font-size: 5rem;
    color: var(--warning-color);
    margin-bottom: 1rem;
}

.modal-content h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

.modal-content p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
}

/* Floating Points */
.floating-points {
    position: fixed;
    font-size: 2rem;
    font-weight: 700;
    color: var(--success-color);
    pointer-events: none;
    z-index: 1000;
    animation: floatUp 1s ease-out forwards;
}

@keyframes floatUp {
    0% { transform: translateY(0); opacity: 1; }
    100% { transform: translateY(-100px); opacity: 0; }
}

/* Responsive Design */
@media (max-width: 1024px) {
    .sidebar {
        width: 250px;
    }
    
    .content {
        padding: 1.5rem;
    }
}

@media (max-width: 768px) {
    .header {
        padding: 1rem;
    }
    
    .header-left .logo {
        font-size: 1.2rem;
    }
    
    .user-info {
        display: none;
    }
    
    .sidebar {
        position: fixed;
        left: -100%;
        top: 60px;
        bottom: 0;
        z-index: 99;
        transition: left 0.3s ease;
    }
    
    .sidebar.open {
        left: 0;
    }
    
    .content {
        padding: 1rem;
    }
    
    .sub-levels {
        grid-template-columns: 1fr;
    }
    
    .achievement-stats {
        grid-template-columns: 1fr;
    }
}

/* Button click effect */
.btn:active {
    transform: scale(0.98);
}

/* Option item click animation */
.option-item:active:not(.correct):not(.incorrect) {
    transform: scale(0.98);
}

/* Correct answer celebration */
.option-item.correct {
    animation: correctPulse 0.5s ease;
}

@keyframes correctPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* Incorrect answer shake */
.option-item.incorrect {
    animation: shake 0.5s ease;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

/* Points update animation */
.user-points {
    position: relative;
}

.user-points.points-updated {
    animation: pointsPulse 0.5s ease;
}

@keyframes pointsPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.2); color: #f59e0b; }
    100% { transform: scale(1); }
}

/* Star animation */
.result-stars i {
    opacity: 0;
    animation: starReveal 0.5s ease forwards;
}

.result-stars i:nth-child(1) { animation-delay: 0.1s; }
.result-stars i:nth-child(2) { animation-delay: 0.3s; }
.result-stars i:nth-child(3) { animation-delay: 0.5s; }

@keyframes starReveal {
    from { 
        opacity: 0; 
        transform: scale(0) rotate(-180deg); 
    }
    to { 
        opacity: 1; 
        transform: scale(1) rotate(0deg); 
    }
}

/* Confetti particles */
.confetti-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 999;
}

.confetti {
    position: absolute;
    width: 10px;
    height: 10px;
    background: #f59e0b;
    animation: confettiFall 3s ease-out forwards;
}

@keyframes confettiFall {
    0% {
        transform: translateY(-100vh) rotate(0deg);
        opacity: 1;
    }
    100% {
        transform: translateY(100vh) rotate(720deg);
        opacity: 0;
    }
}

/* Glow effect for correct answers */
.option-item.correct::after {
    content: '✓';
    font-size: 1.5rem;
    color: var(--success-color);
    font-weight: bold;
}

/* Cross for incorrect */
.option-item.incorrect::after {
    content: '✗';
    font-size: 1.5rem;
    color: var(--danger-color);
    font-weight: bold;
}

/* Card pop in */
.sub-level-card {
    animation: popIn 0.4s ease;
}

@keyframes popIn {
    from { 
        opacity: 0; 
        transform: scale(0.8) translateY(20px); 
    }
    to { 
        opacity: 1; 
        transform: scale(1) translateY(0); 
    }
}

/* Success screen */
.result-content {
    animation: successPop 0.5s ease;
}

@keyframes successPop {
    0% { transform: scale(0.8); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}

/* Button hover glow */
.btn-primary:hover:not(:disabled) {
    box-shadow: 0 0 20px rgba(37, 99, 235, 0.4);
}

.btn-success:hover:not(:disabled) {
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.4);
}

/* Loading spinner */
.spinner {
    border: 3px solid var(--border-color);
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@media (max-width: 480px) {
    .welcome-content h2 {
        font-size: 1.8rem;
    }
    
    .welcome-content p {
        font-size: 1rem;
    }
    
    .start-btn {
        padding: 0.875rem 2rem;
        font-size: 1rem;
    }
}

/* 错题本页面样式 */
.wrong-answers-page {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.wrong-answers-header {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 30px;
}

.wrong-answers-header h2 {
    flex: 1;
}

.wrong-answers-content {
    flex: 1;
    overflow-y: auto;
}

.wrong-answer-card {
    background: #fff;
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 20px;
    border-left: 4px solid #ef4444;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.wrong-answer-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.wrong-answer-header h4 {
    display: flex;
    align-items: center;
    gap: 8px;
    color: #334155;
}

.wrong-answer-type {
    background: #fee2e2;
    color: #991b1b;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
}

.wrong-answer-question {
    font-size: 1.05rem;
    color: #1e293b;
    margin-bottom: 12px;
    line-height: 1.6;
}

.wrong-answer-preview {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 12px;
}

.preview-option {
    background: #f1f5f9;
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.9rem;
    color: #64748b;
}

.wrong-answer-explanation {
    background: #fef9c3;
    padding: 16px;
    border-radius: 8px;
    color: #854d0e;
    line-height: 1.6;
}

.wrong-answer-explanation i {
    margin-right: 8px;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
}

.empty-state i {
    font-size: 4rem;
    color: #10b981;
    margin-bottom: 20px;
}

.empty-state h3 {
    color: #1e293b;
    margin-bottom: 10px;
}

.empty-state p {
    color: #64748b;
}

/* 侧边栏动作按钮 */
.sidebar-actions {
    padding: 0 20px 15px;
}

.sidebar-action-btn {
    width: 100%;
    padding: 12px 16px;
    background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.sidebar-action-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(245, 158, 11, 0.4);
}

.sidebar-action-btn:active {
    transform: translateY(0);
}

/* 多选题样式 */
.checkbox-option {
    display: flex;
    align-items: center;
}

.option-checkbox {
    font-size: 1.4rem;
    margin-right: 12px;
    width: 30px;
    text-align: center;
}

.checkbox-option.selected .option-checkbox {
    color: #2563eb;
}

/* 匹配题样式 */
.matching-container {
    display: flex;
    gap: 20px;
    align-items: flex-start;
    position: relative;
    min-height: 300px;
    padding: 10px;
}

.match-column {
    flex: 1;
    z-index: 2;
}

.match-column h4 {
    text-align: center;
    color: #64748b;
    margin-bottom: 15px;
    font-weight: 600;
}

.match-item {
    padding: 14px 16px;
    background-color: #f8fafc;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    margin-bottom: 10px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 12px;
    user-select: none;
}

.match-item:hover {
    border-color: #2563eb;
    background-color: #eff6ff;
    transform: translateX(3px);
}

.match-item.selected {
    border-color: #2563eb;
    background-color: #dbeafe;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
}

.match-item.active {
    border-color: #2563eb;
    background-color: #dbeafe;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
    transform: scale(1.02);
}

.match-item.matched {
    opacity: 0.9;
    background-color: #ecfdf5;
}

.match-item.correct {
    background-color: #d1fae5;
    border-color: #10b981;
    box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.2);
}

.match-item.incorrect {
    background-color: #fee2e2;
    border-color: #ef4444;
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.2);
}

.match-label {
    display: inline-flex;
    width: 32px;
    height: 32px;
    color: white;
    text-align: center;
    line-height: 32px;
    border-radius: 50%;
    font-weight: 600;
    font-size: 0.9rem;
    flex-shrink: 0;
}

.match-text {
    flex: 1;
}

/* Canvas连线样式 */
.matching-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
}

/* 排序题样式 */
.ordering-container {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.order-item {
    display: flex;
    align-items: center;
    padding: 14px 16px;
    background: #f8fafc;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    cursor: grab;
    transition: all 0.2s;
}

.order-item:hover {
    border-color: #2563eb;
    background: #eff6ff;
}

.order-item.dragging {
    opacity: 0.5;
    cursor: grabbing;
    transform: scale(1.02);
}

.order-item.drag-over {
    border-color: #2563eb;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
}

.order-item.correct {
    background: #ecfdf5;
    border-color: #10b981;
}

.order-item.incorrect {
    background: #fef2f2;
    border-color: #ef4444;
}

.order-number {
    width: 36px;
    height: 36px;
    background: #2563eb;
    color: white;
    text-align: center;
    line-height: 36px;
    border-radius: 50%;
    font-weight: 700;
    margin-right: 12px;
}

.order-text {
    flex: 1;
    color: #1e293b;
}

.order-handle {
    color: #94a3b8;
    cursor: grab;
    font-size: 1.2rem;
}

/* 实战任务徽章 */
.practical-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-top: 10px;
}/* 下拉框配对样式 */
.select-matching-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin: 15px 0;
}

.select-match-row {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 15px;
    background-color: #f8fafc;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    transition: all 0.2s;
}

.select-match-row:hover {
    border-color: #cbd5e1;
    background-color: #f1f5f9;
}

.select-match-row.select-match-correct {
    background-color: #d1fae5;
    border-color: #10b981;
}

.select-match-row.select-match-incorrect {
    background-color: #fee2e2;
    border-color: #ef4444;
}

.select-match-label {
    display: inline-flex;
    min-width: 32px;
    height: 32px;
    padding: 0 10px;
    background-color: #2563eb;
    color: white;
    text-align: center;
    line-height: 32px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    flex-shrink: 0;
}

.select-match-left {
    flex: 1;
    font-weight: 500;
    color: #1e293b;
}

.select-match-arrow {
    color: #94a3b8;
    font-size: 1.2rem;
    font-weight: bold;
}

.select-match-select {
    flex: 1;
    min-width: 200px;
    padding: 8px 12px;
    border: 2px solid #cbd5e1;
    border-radius: 8px;
    background-color: white;
    font-size: 0.95rem;
    color: #1e293b;
    cursor: pointer;
    transition: border-color 0.2s;
}

.select-match-select:focus {
    outline: none;
    border-color: #2563eb;
}

.select-match-select:disabled {
    background-color: #f1f5f9;
    cursor: not-allowed;
}

.select-match-feedback {
    color: #10b981;
    font-weight: 600;
    font-size: 0.9rem;
    white-space: nowrap;
}

.select-match-row.select-match-incorrect .select-match-feedback {
    color: #ef4444;
}