/* ========================================
   CodeLearn - 学习页面样式
   ======================================== */

/* 顶部导航栏 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-lg);
    z-index: 100;
}

.header-left {
    flex: 0 0 auto;
}

.back-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--text-secondary);
    font-size: 14px;
    transition: color var(--transition-fast);
}

.back-btn:hover {
    color: var(--text-primary);
}

.header-center {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    max-width: 500px;
    margin: 0 auto;
}

.course-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.step-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 13px;
    color: var(--text-secondary);
}

.step-name {
    color: var(--accent-primary);
}

.step-progress {
    color: var(--text-muted);
}

.header-center .progress-bar {
    width: 200px;
}

.header-right {
    flex: 0 0 auto;
}

.mode-badge {
    display: inline-block;
    padding: 6px 14px;
    background: var(--accent-primary);
    color: white;
    font-size: 13px;
    font-weight: 500;
    border-radius: 20px;
}

.mode-badge.practice {
    background: var(--accent-success);
}

/* 主内容区 */
.main-content {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: var(--footer-height);
    display: flex;
}

/* 左侧预览区 */
.preview-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
}

.section-header h2 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
}

.preview-container {
    flex: 1;
    position: relative;
    background: white;
    overflow: hidden;
}

.preview-container iframe {
    width: 100%;
    height: 100%;
    border: none;
    background: white;
}

.preview-hint {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    font-size: 12px;
    color: var(--text-secondary);
}

/* 右侧编辑区 */
.editor-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
}

.editor-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.editor-actions .btn {
    padding: 8px 16px;
    font-size: 13px;
}

/* 文件标签 */
.file-tabs {
    display: flex;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    overflow-x: auto;
}

.file-tab {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 10px 16px;
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    color: var(--text-secondary);
    font-size: 13px;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

.file-tab:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.file-tab.active {
    background: var(--bg-primary);
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
}

.file-tab .file-icon {
    font-size: 12px;
}

/* 编辑器容器 */
.editor-container {
    flex: 1;
    position: relative;
    overflow: hidden;
}

.editor-container .CodeMirror {
    height: 100%;
    font-family: 'Fira Code', 'Consolas', 'Monaco', monospace;
    font-size: 14px;
    line-height: 1.6;
    background: var(--bg-primary);
}

.editor-container .CodeMirror-gutters {
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
}

.editor-container .CodeMirror-linenumber {
    color: var(--text-muted);
}

/* 解释面板 */
.explanation-panel {
    max-height: 300px;
    min-height: 100px;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    overflow-y: auto;
}

.explanation-content {
    padding: var(--spacing-md);
    font-size: 14px;
    line-height: 1.8;
    color: var(--text-primary);
}

.explanation-content h1,
.explanation-content h2,
.explanation-content h3 {
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.explanation-content h2 {
    font-size: 16px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: var(--spacing-xs);
}

.explanation-content h3 {
    font-size: 14px;
    color: var(--accent-primary);
}

.explanation-content p {
    margin-bottom: var(--spacing-sm);
}

.explanation-content ul,
.explanation-content ol {
    margin-bottom: var(--spacing-sm);
    padding-left: var(--spacing-lg);
}

.explanation-content li {
    margin-bottom: var(--spacing-xs);
}

.explanation-content code {
    background: var(--bg-tertiary);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-family: 'Fira Code', monospace;
    font-size: 13px;
    color: var(--accent-warning);
}

.explanation-content pre {
    background: var(--bg-tertiary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin-bottom: var(--spacing-sm);
}

.explanation-content pre code {
    background: none;
    padding: 0;
}

.explanation-content strong {
    color: var(--accent-success);
}

/* 底部导航 */
.footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--footer-height);
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-lg);
    z-index: 100;
}

.nav-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.step-indicator {
    font-size: 14px;
    color: var(--text-secondary);
    min-width: 60px;
    text-align: center;
}

/* 侧边栏内容 */
.category-list {
    list-style: none;
}

.category-item {
    margin-bottom: var(--spacing-xs);
}

.category-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background var(--transition-fast);
}

.category-header:hover {
    background: var(--bg-card);
}

.category-header .icon {
    font-size: 12px;
    transition: transform var(--transition-fast);
}

.category-header.expanded .icon {
    transform: rotate(90deg);
}

.category-title {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
}

.step-list {
    list-style: none;
    padding-left: var(--spacing-lg);
    margin-top: var(--spacing-xs);
}

.step-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 13px;
    color: var(--text-secondary);
}

.step-item:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.step-item.active {
    background: var(--accent-primary);
    color: white;
}

.step-item.completed {
    color: var(--accent-success);
}

.step-item.completed::before {
    content: '✓';
    color: var(--accent-success);
}

.step-number {
    font-size: 12px;
    opacity: 0.7;
}

/* 全屏模态框 */
#fullscreenModal .modal-body {
    padding: 0;
}

#fullscreenFrame {
    width: 100%;
    height: 100%;
    border: none;
    background: white;
}