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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, #a8edea 0%, #fed6e3 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #333;
}

.container {
    background: white;
    border-radius: 20px;
    padding: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    width: 95%;
    max-width: 500px;
    text-align: center;
    position: relative;
    min-height: 80vh;
    display: flex;
    flex-direction: column;
}

/* 头部样式 */
.header {
    margin-bottom: 20px;
}

.title {
    color: #2c3e50;
    margin-bottom: 5px;
    font-size: 24px;
    font-weight: 700;
}

.subtitle {
    color: #6c757d;
    font-size: 14px;
}

.header-buttons {
    position: absolute;
    top: 20px;
    right: 20px;
    display: flex;
    gap: 10px;
    z-index: 10;
}

.icon-btn {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
    transition: background 0.2s ease;
    width: 40px;
    height: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.icon-btn:hover {
    background: #f8f9fa;
}

/* 通用 Overlay */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.98);
    border-radius: 20px;
    z-index: 100;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding-top: 40px;
    transition: opacity 0.3s ease;
    opacity: 1;
    pointer-events: auto;
    overflow-y: auto;
}

.overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.overlay-content {
    width: 90%;
    max-width: 500px;
    background: white;
    padding-bottom: 40px;
}

.overlay-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    position: sticky;
    top: 0;
    background: white;
    z-index: 10;
    padding-bottom: 10px;
    border-bottom: 1px solid #f0f0f0;
}

.overlay-header h2 {
    font-size: 22px;
    color: #2c3e50;
    margin: 0;
}

.close-btn {
    background: none;
    border: none;
    font-size: 32px;
    color: #6c757d;
    cursor: pointer;
    padding: 0 10px;
    line-height: 1;
}

/* 设置面板样式 */
.settings-content {
    max-width: 400px;
}

.setting-group {
    margin-bottom: 25px;
    text-align: left;
}

.setting-label {
    font-size: 16px;
    color: #495057;
    margin-bottom: 10px;
    font-weight: 600;
    display: block;
}

.mode-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.mode-btn {
    padding: 10px;
    border: 1px solid #ced4da;
    border-radius: 8px;
    background: white;
    color: #495057;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 14px;
}

.mode-btn.active {
    background: #a8edea;
    border-color: #56ccf2;
    color: #0056b3;
    font-weight: 600;
}

.level-select {
    width: 100%;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid #ced4da;
    background-color: white;
    font-size: 16px;
}

/* 数据分析面板样式 */
.analytics-content {
    width: 100%;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-bottom: 25px;
}

.stat-card {
    background: #f8f9fa;
    padding: 15px 10px;
    border-radius: 12px;
    text-align: center;
    border: 1px solid #e9ecef;
}

.stat-label {
    font-size: 12px;
    color: #6c757d;
    margin-bottom: 5px;
}

.stat-value {
    font-size: 18px;
    font-weight: 800;
    color: #2c3e50;
}

.chart-container {
    margin-bottom: 25px;
    text-align: left;
}

.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.chart-header h3 {
    font-size: 16px;
    color: #495057;
    margin: 0;
}

.chart-tabs {
    display: flex;
    gap: 5px;
    background: #f1f3f5;
    padding: 3px;
    border-radius: 8px;
}

.chart-tab {
    border: none;
    background: none;
    padding: 4px 8px;
    border-radius: 6px;
    font-size: 12px;
    color: #6c757d;
    cursor: pointer;
    transition: all 0.2s;
}

.chart-tab.active {
    background: white;
    color: #2c3e50; /* Changed from theme color to dark grey for better contrast */
    font-weight: 600;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.chart-view {
    display: none;
    height: 180px; /* Slightly taller for T4 charts */
    position: relative;
    border: 1px solid #e9ecef; /* Added border for clarity */
    border-radius: 8px;
    padding: 10px;
}

.chart-view.active {
    display: block;
}

.no-data {
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #adb5bd;
    font-style: italic;
}

/* SVG Chart Styles */
.bar-chart-svg, .line-chart-svg {
    width: 100%;
    height: 100%;
    overflow: visible;
}

.chart-bar-rect {
    fill: #a8edea;
    transition: height 0.3s;
}
.chart-bar-rect:hover {
    fill: #56ccf2;
}

.line-path {
    fill: none;
    stroke: #56ccf2;
    stroke-width: 2px;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.data-point {
    fill: #56ccf2;
    stroke: white;
    stroke-width: 2px;
    r: 4;
}

.chart-label {
    font-size: 10px;
    fill: #6c757d;
    text-anchor: middle;
}

.chart-axis {
    stroke: #e9ecef;
    stroke-width: 1px;
}

/* History List */
.history-list {
    text-align: left;
}

.history-list h3 {
    font-size: 16px;
    margin-bottom: 15px;
    color: #495057;
}

.history-items {
    max-height: 200px;
    overflow-y: auto;
}

.history-item {
    display: flex;
    justify-content: space-between;
    padding: 10px;
    border-bottom: 1px solid #f0f0f0;
    font-size: 12px;
}

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

.history-time {
    color: #adb5bd;
    width: 80px;
}

.history-detail {
    flex: 1;
    display: flex;
    gap: 10px;
    color: #495057;
}

.history-result {
    font-weight: bold;
}
.result-correct { color: #28a745; }
.result-wrong { color: #dc3545; }

/* 统计表格样式 */
.stats-table-container {
    margin-top: 15px;
    overflow-x: auto;
}

.stats-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 12px;
}

.stats-table th, .stats-table td {
    padding: 8px;
    text-align: center;
    border-bottom: 1px solid #f0f0f0;
}

.stats-table th {
    color: #6c757d;
    font-weight: 600;
}

.stats-table tr:hover {
    background: #f8f9fa;
}

.score-high { color: #28a745; font-weight: bold; }
.score-medium { color: #fd7e14; }
.score-low { color: #dc3545; }
.weak-note { background-color: #fff3f3; }
.weak-note .note-name::after {
    content: "⚠️";
    font-size: 10px;
    margin-left: 2px;
}


/* 等级显示 */
.level-container {
    margin-bottom: 20px;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 10px;
    display: inline-block;
}

.level-info {
    font-size: 14px;
    color: #495057;
}

.current-level {
    font-weight: 800;
    color: #0056b3;
    font-size: 18px;
    margin: 0 5px;
}

.level-type {
    color: #6c757d;
}

/* 显示区域 */
.display-area {
    background: white;
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 25px;
    min-height: 250px; /* 增加最小高度以适应五线谱 */
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border: 2px solid #e9ecef;
    transition: all 0.3s ease;
}

.correct-state {
    border-color: #28a745;
    background-color: #f0fff4;
}

.question-container {
    margin-bottom: 15px;
}

.question-main {
    font-size: 64px;
    font-weight: 800;
    color: #2c3e50;
    margin-bottom: 5px;
    line-height: 1;
}

.question-sub {
    font-size: 20px;
    color: #6c757d;
    height: 24px; /* 保持高度避免跳动 */
}

/* 五线谱容器 */
.stave-container {
    width: 100%;
    height: 120px;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    margin-top: 10px;
}

.hidden-sub, .hidden-stave {
    opacity: 0;
    visibility: hidden;
}

/* 选项区域 */
.options-container {
    margin-bottom: 25px;
}

.options {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

.option-btn {
    min-width: 60px;
    height: 60px;
    border: none;
    border-radius: 12px;
    background: white;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    font-size: 24px;
    font-weight: 600;
    color: #495057;
    cursor: pointer;
    transition: all 0.1s;
    border-bottom: 4px solid #dee2e6;
}

.option-btn:active {
    transform: translateY(2px);
    border-bottom-width: 2px;
}

.option-btn:disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

.option-btn.correct-highlight {
    background-color: #d4edda;
    border-color: #28a745;
    color: #155724;
    border-bottom-color: #155724;
    transform: translateY(2px);
    border-bottom-width: 2px;
}

.option-btn.error {
    background-color: #f8d7da;
    border-color: #dc3545;
    color: #721c24;
    border-bottom-color: #721c24;
    animation: shake 0.5s;
}

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

/* 反馈区域 */
.feedback {
    height: 30px;
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
}

.feedback.correct {
    color: #28a745;
}

.feedback.wrong {
    color: #dc3545;
}

/* 进度条 */
.progress-container {
    margin-top: auto;
    width: 100%;
}

.progress-text {
    font-size: 14px;
    color: #6c757d;
    margin-bottom: 5px;
}

.progress-bar-container {
    width: 100%;
    height: 8px;
    background: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    transition: width 0.3s ease, background-color 0.3s ease;
}

.progress-bar.red { background-color: #dc3545; }
.progress-bar.orange { background-color: #fd7e14; }
.progress-bar.green { background-color: #28a745; }

.hidden {
    display: none !important;
}

/* 移动端适配 */
@media (max-width: 480px) {
    .question-main {
        font-size: 48px;
    }
    
    .option-btn {
        min-width: 50px;
        height: 50px;
        font-size: 20px;
    }
    
    .mode-buttons {
        grid-template-columns: 1fr;
    }
}