/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #4CAF50;
    --primary-dark: #388E3C;
    --secondary-color: #2196F3;
    --error-color: #f44336;
    --warning-color: #ff9800;
    --success-color: #4CAF50;
    --bg-color: #f5f5f5;
    --card-bg: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --border-color: #e0e0e0;
    --shadow: 0 2px 10px 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);
    min-height: 100vh;
    overflow-x: hidden;
}

.app-container {
    max-width: 100%;
    min-height: 100vh;
    position: relative;
}

/* 页面切换 */
.page {
    display: none;
    min-height: 100vh;
    padding-bottom: 20px;
}

.page.active {
    display: block;
}

/* 头部 */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 15px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}

.header h1 {
    font-size: 1.3rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

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

.icon-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    position: relative;
    transition: background 0.3s;
}

.icon-btn:hover {
    background: rgba(255, 255, 255, 0.3);
}

.icon-btn .badge {
    position: absolute;
    top: -5px;
    right: -5px;
    background: var(--error-color);
    color: white;
    font-size: 0.7rem;
    padding: 2px 6px;
    border-radius: 10px;
    min-width: 18px;
    text-align: center;
}

.icon-btn .badge:empty,
.icon-btn .badge:contains('0') {
    display: none;
}

/* 模式选择 */
.mode-selector {
    display: flex;
    gap: 10px;
    padding: 15px;
    background: var(--card-bg);
    margin: 15px;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.mode-btn {
    flex: 1;
    background: var(--bg-color);
    border: 2px solid transparent;
    padding: 12px 8px;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
}

.mode-btn i {
    font-size: 1.5rem;
    color: var(--text-secondary);
}

.mode-btn span {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.mode-btn.active {
    background: #E8F5E9;
    border-color: var(--primary-color);
}

.mode-btn.active i,
.mode-btn.active span {
    color: var(--primary-color);
}

/* 分类面板 */
.category-panel {
    background: var(--card-bg);
    margin: 0 15px 15px;
    padding: 15px;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.category-panel h3 {
    margin-bottom: 12px;
    color: var(--text-primary);
}

.category-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.category-item {
    background: var(--bg-color);
    padding: 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    border: 2px solid transparent;
}

.category-item:hover {
    background: #E8F5E9;
}

.category-item.selected {
    border-color: var(--primary-color);
    background: #E8F5E9;
}

.category-item .name {
    font-weight: 500;
    color: var(--text-primary);
}

.category-item .range {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 3px;
}

/* 进度 */
.progress-section {
    padding: 0 15px;
    margin-bottom: 15px;
}

.progress-info {
    text-align: center;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.progress-info #current-num {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary-color);
}

.progress-bar {
    height: 8px;
    background: #e0e0e0;
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 1%;
}

/* 题目卡片 */
.question-section {
    padding: 0 15px;
    margin-bottom: 15px;
}

.question-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--shadow);
}

.question-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 15px;
}

.question-category {
    background: #E3F2FD;
    color: var(--secondary-color);
    padding: 4px 12px;
    border-radius: 15px;
    font-size: 0.8rem;
}

.question-id {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.question-text {
    font-size: 1.3rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 20px;
    line-height: 1.5;
    text-align: center;
}

.speak-btn {
    width: 100%;
    background: linear-gradient(135deg, var(--secondary-color), #1976D2);
    color: white;
    border: none;
    padding: 12px;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.speak-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.4);
}

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

.speak-btn.small {
    padding: 8px 16px;
    font-size: 0.9rem;
    width: auto;
}

/* 录音区域 */
.record-section {
    padding: 0 15px;
    margin-bottom: 15px;
}

.record-status {
    text-align: center;
    padding: 15px;
    color: var(--text-secondary);
}

.record-status i {
    font-size: 2rem;
    margin-bottom: 10px;
    display: block;
    color: var(--text-secondary);
}

.record-status.recording i {
    color: var(--error-color);
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.record-btn {
    width: 100%;
    background: linear-gradient(135deg, var(--error-color), #D32F2F);
    color: white;
    border: none;
    padding: 15px;
    border-radius: 50px;
    font-size: 1.1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    transition: all 0.3s;
}

.record-btn:hover {
    transform: scale(1.02);
    box-shadow: 0 4px 15px rgba(244, 67, 54, 0.4);
}

.record-btn.recording {
    background: var(--error-color);
    animation: recording-pulse 1.5s infinite;
}

@keyframes recording-pulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(244, 67, 54, 0.4); }
    50% { box-shadow: 0 0 0 15px rgba(244, 67, 54, 0); }
}

.user-answer {
    background: var(--card-bg);
    margin-top: 15px;
    padding: 15px;
    border-radius: 10px;
    box-shadow: var(--shadow);
    min-height: 60px;
    color: var(--text-primary);
    font-size: 1rem;
}

.user-answer:empty {
    display: none;
}

.user-answer::before {
    content: '你的回答：';
    display: block;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

/* 结果区域 */
.result-section {
    padding: 0 15px;
    margin-bottom: 15px;
}

.result-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--shadow);
    margin-bottom: 15px;
}

.result-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.result-icon {
    font-size: 1.8rem;
}

.result-icon.correct {
    color: var(--success-color);
}

.result-icon.wrong {
    color: var(--error-color);
}

.result-text {
    font-size: 1.2rem;
    font-weight: 600;
}

.result-text.correct {
    color: var(--success-color);
}

.result-text.wrong {
    color: var(--error-color);
}

.result-detail {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.reference-section,
.tips-section {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 15px;
    box-shadow: var(--shadow);
    margin-bottom: 15px;
}

.reference-section h4,
.tips-section h4 {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-primary);
    margin-bottom: 10px;
    font-size: 0.9rem;
}

.reference-text {
    color: var(--text-primary);
    font-size: 1rem;
    line-height: 1.6;
    padding: 12px;
    background: #FFF8E1;
    border-radius: 8px;
    border-left: 4px solid var(--warning-color);
    margin-bottom: 10px;
}

.tips-text {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
}

/* 操作按钮 */
.action-buttons {
    padding: 0 15px;
    display: flex;
    gap: 15px;
}

.action-btn {
    flex: 1;
    border: none;
    padding: 15px;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all 0.3s;
}

.action-btn.primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
}

.action-btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(76, 175, 80, 0.4);
}

.action-btn.secondary {
    background: var(--card-bg);
    color: var(--text-secondary);
    border: 2px solid var(--border-color);
}

.action-btn.secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* 返回按钮 */
.back-btn {
    background: none;
    border: none;
    color: white;
    font-size: 1.2rem;
    cursor: pointer;
    padding: 5px;
}

.clear-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    padding: 8px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 5px;
}

/* 错题列表 */
.wrong-list {
    padding: 15px;
}

.wrong-item {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 15px;
    margin-bottom: 10px;
    box-shadow: var(--shadow);
}

.wrong-item .question {
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.wrong-item .wrong-count {
    font-size: 0.8rem;
    color: var(--error-color);
    margin-bottom: 8px;
}

.wrong-item .actions {
    display: flex;
    gap: 10px;
}

.wrong-item .practice-btn {
    flex: 1;
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 8px;
    border-radius: 6px;
    cursor: pointer;
}

.wrong-item .delete-btn {
    background: var(--error-color);
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 6px;
    cursor: pointer;
}

.empty-state {
    text-align: center;
    padding: 50px 20px;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 15px;
    color: var(--border-color);
}

/* 设置页面 */
.settings-content {
    padding: 15px;
}

.setting-item {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 15px;
    margin-bottom: 15px;
    box-shadow: var(--shadow);
}

.setting-item label {
    display: block;
    font-weight: 500;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.setting-item input[type="range"] {
    width: 100%;
    margin-bottom: 5px;
}

.setting-item input[type="password"],
.setting-item input[type="text"] {
    width: 100%;
    padding: 10px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.setting-item input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.setting-item small {
    display: block;
    margin-top: 8px;
    color: var(--text-secondary);
    font-size: 0.8rem;
}

/* 加载 */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-overlay p {
    color: white;
    margin-top: 15px;
}

/* 提示消息 */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 12px 25px;
    border-radius: 25px;
    z-index: 1001;
    animation: fadeInUp 0.3s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translate(-50%, 20px);
    }
    to {
        opacity: 1;
        transform: translate(-50%, 0);
    }
}

/* 隐藏 */
.hidden {
    display: none !important;
}

/* 响应式 */
@media (min-width: 768px) {
    .app-container {
        max-width: 500px;
        margin: 0 auto;
    }

    .question-text {
        font-size: 1.5rem;
    }
}