/* ===================================
   Higher Math Domain Knowledge Graph
   Main Stylesheet
   =================================== */

/* CSS Variables for Theming */
:root {
    /* Domain Colors */
    --domain-1-color: #667eea;  /* 变化与逼近 */
    --domain-2-color: #f093fb;  /* 结构与累积 */
    --domain-3-color: #4facfe;  /* 优化与决策 */
    --domain-4-color: #fa709a;  /* 不确定性处理 */
    --domain-5-color: #00f2fe;  /* 真实问题建模 */
    
    /* UI Colors */
    --primary-bg: #ffffff;
    --secondary-bg: #f8f9fa;
    --sidebar-bg: #2c3e50;
    --sidebar-text: #ecf0f1;
    --header-bg: #34495e;
    --border-color: #dfe6e9;
    --text-primary: #2d3436;
    --text-secondary: #636e72;
    --accent-color: #667eea;
    --hover-bg: #e8eaf6;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    --font-size-sm: 12px;
    --font-size-base: 14px;
    --font-size-lg: 16px;
    --font-size-xl: 20px;
    --font-size-xxl: 24px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    color: var(--text-primary);
    background-color: var(--secondary-bg);
    overflow: hidden;
}

/* Header */
.app-header {
    background: linear-gradient(135deg, var(--header-bg) 0%, #2c3e50 100%);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    box-shadow: var(--shadow);
    z-index: 100;
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-sm);
    gap: var(--spacing-md);
}

.header-title-section {
    flex: 1;
}

.header-content h1 {
    font-size: var(--font-size-xxl);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.header-content .subtitle {
    font-size: var(--font-size-base);
    opacity: 0.9;
}

.header-user-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-welcome {
    font-size: var(--font-size-sm);
    opacity: 0.9;
}

.btn-logout {
    padding: 6px 16px;
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 6px;
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-logout:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.5);
}

/* 学域标识：头部五大学域徽章 */
.header-domain-badges {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
    justify-content: center;
}

.domain-badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    border-radius: 999px;
    font-size: var(--font-size-sm);
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.25);
    transition: transform var(--transition-fast), background var(--transition-fast);
}

.domain-badge:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: scale(1.05);
}

.domain-badge[data-domain="domain-1"] { border-color: #667eea; }
.domain-badge[data-domain="domain-2"] { border-color: #f093fb; }
.domain-badge[data-domain="domain-3"] { border-color: #4facfe; }
.domain-badge[data-domain="domain-4"] { border-color: #fa709a; }
.domain-badge[data-domain="domain-5"] { border-color: #00f2fe; }

.domain-badge--active[data-domain="domain-1"] { background: rgba(102, 126, 234, 0.4); border-color: #667eea; }
.domain-badge--active[data-domain="domain-2"] { background: rgba(240, 147, 251, 0.4); border-color: #f093fb; }
.domain-badge--active[data-domain="domain-3"] { background: rgba(79, 172, 254, 0.4); border-color: #4facfe; }
.domain-badge--active[data-domain="domain-4"] { background: rgba(250, 112, 154, 0.4); border-color: #fa709a; }
.domain-badge--active[data-domain="domain-5"] { background: rgba(0, 242, 254, 0.4); border-color: #00f2fe; }

/* App Container */
.app-container {
    display: flex;
    height: calc(100vh - 80px);
    position: relative;
}

/* Sidebar */
.sidebar {
    width: 300px;
    background-color: var(--sidebar-bg);
    color: var(--sidebar-text);
    padding: var(--spacing-lg);
    overflow-y: auto;
    box-shadow: 2px 0 8px rgba(0, 0, 0, 0.15);
    transition: transform var(--transition-base);
    z-index: 50;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.sidebar-header h2 {
    font-size: var(--font-size-xl);
    font-weight: 600;
}

.sidebar-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--sidebar-text);
    font-size: var(--font-size-xl);
    cursor: pointer;
    padding: var(--spacing-xs);
}

/* Search Section */
.search-section {
    margin-bottom: var(--spacing-lg);
}

.search-input {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: var(--font-size-base);
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--sidebar-text);
    transition: background-color var(--transition-fast);
}

.search-input::placeholder {
    color: rgba(236, 240, 241, 0.6);
}

.search-input:focus {
    outline: none;
    background-color: rgba(255, 255, 255, 0.15);
    border-color: var(--accent-color);
}

.search-results-count {
    margin-top: var(--spacing-sm);
    font-size: var(--font-size-sm);
    color: rgba(236, 240, 241, 0.8);
}

/* 学域概览：侧边栏学域模块特色 */
.domain-overview-section {
    margin-bottom: var(--spacing-md);
}

.domain-overview-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.domain-overview-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.06);
    border-left: 4px solid;
    font-size: var(--font-size-sm);
    transition: background var(--transition-fast);
}

.domain-overview-item:hover {
    background: rgba(255, 255, 255, 0.1);
}

.domain-overview-item .domain-ov-icon { font-size: 1.2rem; flex-shrink: 0; }
.domain-overview-item .domain-ov-body {
    flex: 1;
    min-width: 0;
}
.domain-overview-item .domain-ov-row {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-wrap: wrap;
}
.domain-overview-item .domain-ov-name { font-weight: 600; }
.domain-overview-item .domain-ov-count {
    background: rgba(255,255,255,0.2);
    padding: 2px 6px;
    border-radius: 999px;
    font-size: 11px;
}
.domain-overview-item .domain-ov-idea {
    display: block;
    margin-top: 4px;
    font-size: 11px;
    opacity: 0.9;
    color: rgba(236, 240, 241, 0.95);
    line-height: 1.3;
}

.domain-overview-item[data-domain="domain-1"] { border-left-color: #667eea; }
.domain-overview-item[data-domain="domain-2"] { border-left-color: #f093fb; }
.domain-overview-item[data-domain="domain-3"] { border-left-color: #4facfe; }
.domain-overview-item[data-domain="domain-4"] { border-left-color: #fa709a; }
.domain-overview-item[data-domain="domain-5"] { border-left-color: #00f2fe; }

.domain-overview-item--active { background: rgba(255, 255, 255, 0.12); font-weight: 600; }
.domain-overview-item--active[data-domain="domain-1"] { border-left-width: 5px; box-shadow: 0 0 0 1px rgba(102, 126, 234, 0.2); }
.domain-overview-item--active[data-domain="domain-2"] { border-left-width: 5px; box-shadow: 0 0 0 1px rgba(240, 147, 251, 0.2); }
.domain-overview-item--active[data-domain="domain-3"] { border-left-width: 5px; box-shadow: 0 0 0 1px rgba(79, 172, 254, 0.2); }
.domain-overview-item--active[data-domain="domain-4"] { border-left-width: 5px; box-shadow: 0 0 0 1px rgba(250, 112, 154, 0.2); }
.domain-overview-item--active[data-domain="domain-5"] { border-left-width: 5px; box-shadow: 0 0 0 1px rgba(0, 242, 254, 0.2); }

/* 学域模式说明 */
.domain-mode-section { margin-bottom: var(--spacing-md); }
.domain-mode-intro {
    font-size: var(--font-size-sm);
    color: rgba(236, 240, 241, 0.9);
    line-height: 1.4;
    margin-bottom: var(--spacing-sm);
}
.domain-mode-details {
    font-size: var(--font-size-sm);
    color: rgba(236, 240, 241, 0.85);
}
.domain-mode-details summary {
    cursor: pointer;
    padding: var(--spacing-xs) 0;
    list-style: none;
    display: flex;
    align-items: center;
    gap: 6px;
}
.domain-mode-details summary::-webkit-details-marker { display: none; }
.domain-mode-details summary::before { content: '▶'; font-size: 10px; transition: transform var(--transition-fast); }
.domain-mode-details[open] summary::before { transform: rotate(90deg); }
.domain-mode-list {
    margin: var(--spacing-sm) 0 0;
    padding-left: 1.2rem;
    list-style: none;
}
.domain-mode-list li {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 4px;
}
.domain-mode-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--d, #999);
    flex-shrink: 0;
}

/* Filter Sections */
.filter-section {
    margin-bottom: var(--spacing-lg);
}

.filter-section h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--sidebar-text);
}

/* Domain Filters */
.domain-filters {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.domain-filter-item {
    display: flex;
    align-items: center;
    padding: var(--spacing-sm);
    border-radius: 6px;
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.domain-filter-item:hover {
    background-color: rgba(255, 255, 255, 0.05);
}

.domain-filter-item input[type="checkbox"] {
    margin-right: var(--spacing-sm);
    cursor: pointer;
}

.domain-filter-item label {
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex: 1;
}

.domain-icon {
    font-size: var(--font-size-lg);
}

/* Chapter Select */
.chapter-select {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: var(--font-size-base);
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--sidebar-text);
    cursor: pointer;
}

.chapter-select option {
    background-color: var(--sidebar-bg);
    color: var(--sidebar-text);
}

/* Difficulty Slider */
.difficulty-slider {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.difficulty-slider input[type="range"] {
    width: 100%;
    cursor: pointer;
}

.difficulty-labels {
    text-align: center;
    font-size: var(--font-size-base);
    color: var(--sidebar-text);
}

/* Stats Section */
.stats-section {
    background-color: rgba(255, 255, 255, 0.05);
    padding: var(--spacing-md);
    border-radius: 8px;
    margin-bottom: var(--spacing-lg);
}

.stats-section h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
}

.stats-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.stat-item {
    display: flex;
    justify-content: space-between;
    font-size: var(--font-size-base);
}

.stat-label {
    color: rgba(236, 240, 241, 0.8);
}

.stat-value {
    font-weight: 600;
    color: var(--accent-color);
}

.progress-bar {
    margin-top: 8px;
    width: 100%;
    height: 6px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.08);
    overflow: hidden;
}

.progress-bar__fill {
    height: 100%;
    width: 0%;
    border-radius: inherit;
    background: linear-gradient(90deg, #4caf50 0%, #8bc34a 100%);
    transition: width var(--transition-base);
}

/* Clear Filters Button */
.clear-filters-btn {
    width: 100%;
    padding: var(--spacing-md);
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--sidebar-text);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    font-size: var(--font-size-base);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.clear-filters-btn:hover {
    background-color: rgba(255, 255, 255, 0.15);
    border-color: var(--accent-color);
}

/* Main Content */
.main-content {
    flex: 1;
    position: relative;
    background-color: var(--primary-bg);
    overflow: hidden;
}

/* Zoom Controls */
.zoom-controls {
    position: absolute;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    z-index: 10;
}

.zoom-btn {
    width: 40px;
    height: 40px;
    background-color: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: var(--font-size-lg);
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.zoom-btn:hover {
    background-color: var(--hover-bg);
    border-color: var(--accent-color);
    transform: scale(1.05);
}

.zoom-btn:active {
    transform: scale(0.95);
}

/* Graph Canvas */
.graph-canvas {
    width: 100%;
    height: 100%;
    position: relative;
}

.graph-canvas svg {
    width: 100%;
    height: 100%;
    position: relative;
    z-index: 0;
}

/* 学域图例：图谱上的学域颜色说明（始终浮在图谱上方） */
.domain-legend {
    position: absolute;
    bottom: var(--spacing-md);
    left: var(--spacing-md);
    z-index: 10;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(6px);
    border-radius: 10px;
    padding: var(--spacing-sm) var(--spacing-md);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.domain-legend-title {
    font-size: var(--font-size-sm);
    font-weight: 700;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.domain-legend-list {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.domain-legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    color: var(--text-primary);
    cursor: default;
}

.legend-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    flex-shrink: 0;
    border: 1px solid rgba(0,0,0,0.1);
}

/* Node Styles */
.node {
    cursor: pointer;
    transition: all var(--transition-fast);
}

.node circle {
    stroke: white;
    stroke-width: 2px;
    transition: all var(--transition-fast);
}

/* 按节点类型描边，与详情/技能类型色一致 */
.node-type-concept circle { stroke: #3f51b5; }
.node-type-theorem circle { stroke: #c2185b; }
.node-type-method circle { stroke: #2e7d32; }
.node-type-application circle { stroke: #1565c0; }

.node-type-badge {
    fill: var(--text-secondary);
    font-size: 8px;
}
.node-type-concept .node-type-badge { fill: #3f51b5; }
.node-type-theorem .node-type-badge { fill: #c2185b; }
.node-type-method .node-type-badge { fill: #2e7d32; }
.node-type-application .node-type-badge { fill: #1565c0; }

.graph-content.zoomed-out .node-type-badge {
    font-size: 7px;
    opacity: 0.75;
}

.node:hover circle {
    stroke-width: 3px;
    filter: brightness(1.1);
}

.node.highlighted circle {
    stroke-width: 4px;
    stroke: #ffd700;
}

.node.faded {
    opacity: 0.3;
}

.node.path-node circle {
    stroke: #4CAF50;
    stroke-width: 4px;
    filter: drop-shadow(0 0 8px rgba(76, 175, 80, 0.6));
    animation: pathPulse 2s ease-in-out infinite;
}

.node.path-node text {
    font-weight: 600;
    fill: var(--text-primary);
}

@keyframes pathPulse {
    0%, 100% {
        stroke-width: 4px;
    }
    50% {
        stroke-width: 5px;
    }
}

.node text {
    font-size: 10px;
    pointer-events: none;
    text-anchor: middle;
    fill: var(--text-primary);
    paint-order: stroke fill;
    stroke: rgba(255, 255, 255, 0.9);
    stroke-width: 2px;
    stroke-linejoin: round;
    transition: opacity var(--transition-fast), font-size var(--transition-fast);
}

/* 悬停时放大标签，便于阅读 */
.node:hover text {
    font-size: 12px;
    font-weight: 600;
}

/* 缩小时弱化标签，减少散点感、提升可读性 */
.graph-content.zoomed-out .node text {
    font-size: 8px;
    opacity: 0.6;
}

/* Path Progress Indicators */
.path-indicator {
    pointer-events: none;
}

.path-indicator circle {
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.3));
}

.path-indicator text {
    pointer-events: none;
}

/* Edge Styles */
.link {
    stroke: #999;
    stroke-opacity: 0.6;
    fill: none;
    transition: all var(--transition-fast);
}

.link.prerequisite {
    stroke: #667eea;
}

.link.cross-domain {
    stroke: #fa709a;
    stroke-dasharray: 5, 5;
}

.link.highlighted {
    stroke-width: 3px;
    stroke-opacity: 1;
}

.link.faded {
    stroke-opacity: 0.1;
}

.link.path-link {
    stroke: #4CAF50;
    stroke-width: 4px;
    stroke-opacity: 1;
    filter: drop-shadow(0 0 4px rgba(76, 175, 80, 0.4));
    animation: pathLinkPulse 2s ease-in-out infinite;
}

@keyframes pathLinkPulse {
    0%, 100% {
        stroke-opacity: 1;
    }
    50% {
        stroke-opacity: 0.7;
    }
}

/* Tooltip */
.tooltip {
    position: absolute;
    padding: 0;
    background-color: rgba(0, 0, 0, 0.95);
    color: white;
    border-radius: 8px;
    font-size: var(--font-size-sm);
    pointer-events: none;
    z-index: 1000;
    max-width: 300px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
    display: none;
    animation: tooltipFadeIn 0.2s ease;
}

@keyframes tooltipFadeIn {
    from {
        opacity: 0;
        transform: translateY(-5px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.tooltip-header {
    padding: var(--spacing-md);
    background-color: rgba(255, 255, 255, 0.1);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px 8px 0 0;
}

.tooltip-header strong {
    font-size: var(--font-size-base);
    font-weight: 600;
}

.tooltip-body {
    padding: var(--spacing-md);
}

.tooltip-item {
    margin-bottom: var(--spacing-sm);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.tooltip-item:last-child {
    margin-bottom: 0;
}

.tooltip-label {
    font-size: var(--font-size-sm);
    opacity: 0.8;
    font-weight: 500;
}

.tooltip-value {
    font-size: var(--font-size-sm);
    line-height: 1.4;
}

.tooltip-footer {
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: rgba(255, 255, 255, 0.05);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 0 0 8px 8px;
    text-align: center;
}

.tooltip-footer small {
    font-size: 11px;
    opacity: 0.7;
    font-style: italic;
}

/* Detail Panel */
.detail-panel {
    position: absolute;
    right: -400px;
    top: 0;
    width: 400px;
    height: 100%;
    background-color: white;
    box-shadow: -2px 0 8px rgba(0, 0, 0, 0.15);
    transition: right var(--transition-base);
    z-index: 60;
    overflow-y: auto;
}

.detail-panel.open {
    right: 0;
}

/* Skill 内容展示面板（去运用时自动生成） */
.skill-panel {
    position: absolute;
    right: -420px;
    top: 0;
    width: 420px;
    max-width: 95vw;
    height: 100%;
    background: linear-gradient(180deg, #fafbff 0%, #fff 100%);
    box-shadow: -2px 0 12px rgba(102, 126, 234, 0.15);
    transition: right var(--transition-base);
    z-index: 70;
    overflow-y: auto;
}

.skill-panel.open {
    right: 0;
}

.skill-panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.12) 0%, rgba(118, 75, 162, 0.08) 100%);
    border-bottom: 1px solid rgba(102, 126, 234, 0.2);
    position: sticky;
    top: 0;
    z-index: 10;
}

.skill-panel-header-text {
    min-width: 0;
}

.skill-panel-header h2 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--accent-color);
}

.skill-panel-subtitle {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-top: 2px;
    margin-bottom: 0;
}

.skill-panel-subtitle.hidden {
    display: none;
}

.skill-panel-content {
    padding: var(--spacing-lg);
}

.skill-content-header {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.skill-type-badge {
    padding: 4px 10px;
    border-radius: 999px;
    font-size: var(--font-size-sm);
    font-weight: 600;
}

.skill-type-concept { background: #e8eaf6; color: #3f51b5; }
.skill-type-theorem { background: #fce4ec; color: #c2185b; }
.skill-type-method { background: #e8f5e9; color: #2e7d32; }
.skill-type-application { background: #e3f2fd; color: #1565c0; }

/* 详情面板：节点类型徽章与推荐学习方式 */
.detail-node-type-row {
    margin-bottom: var(--spacing-md);
}
.detail-node-type-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 999px;
    font-size: var(--font-size-sm);
    font-weight: 600;
}
.detail-type-hint {
    background: rgba(102, 126, 234, 0.06);
    border-left: 4px solid var(--accent-color);
    border-radius: 0 8px 8px 0;
}
.detail-type-hint h3 {
    color: var(--accent-color);
}

/* 侧栏：节点类型筛选 */
.node-type-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 12px;
}
.node-type-filter-item {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: var(--font-size-sm);
    color: var(--sidebar-text);
    cursor: pointer;
}
.node-type-filter-item input {
    cursor: pointer;
}

/* 悬停提示中的类型值颜色 */
.tooltip-type-concept { color: #9fa8da; }
.tooltip-type-theorem { color: #f48fb1; }
.tooltip-type-method { color: #81c784; }
.tooltip-type-application { color: #64b5f6; }

.skill-domain-tag {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.skill-content-title {
    font-size: var(--font-size-xxl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.skill-content-desc {
    margin-bottom: var(--spacing-lg);
}

.phase2-item {
    border: 1px solid #e5e7eb;
    border-radius: 10px;
    background: #ffffff;
    padding: 10px 12px;
    margin-bottom: 10px;
}

.phase2-item summary {
    cursor: pointer;
    font-weight: 600;
    color: #333333;
}

.phase2-kv {
    font-size: 13px;
    color: #555555;
    margin-top: 6px;
}

.phase2-kv strong {
    color: #333333;
}

.phase2-pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 2px 8px;
    border-radius: 999px;
    background: #eef6ff;
    color: #2563eb;
    font-size: 12px;
    margin-right: 4px;
}

.phase2-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 4px;
}

.phase2-tag {
    font-size: 12px;
    padding: 2px 8px;
    border-radius: 999px;
    background: #f3f4f6;
    color: #374151;
}

/* Phase2 深度内容：导语与摘要行 */
.phase2-intro .phase2-intro-line {
    margin-top: 6px;
    line-height: 1.5;
}

.phase2-item summary {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 6px 10px;
}

.phase2-summary-id {
    flex-shrink: 0;
    font-size: 11px;
    color: var(--text-secondary);
    font-weight: 500;
}

.phase2-difficulty-stars {
    flex-shrink: 0;
    font-size: 12px;
    color: #f59e0b;
    letter-spacing: 0.5px;
}

.phase2-time-badge {
    flex-shrink: 0;
    font-size: 11px;
    padding: 2px 6px;
    border-radius: 6px;
    background: #f0fdf4;
    color: #15803d;
}

.phase2-summary-text {
    flex: 1;
    min-width: 0;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.35;
}

.phase2-item-body {
    margin-top: 10px;
    padding-top: 8px;
    border-top: 1px solid #f3f4f6;
}

/* Phase2 GGB 嵌入区 */
.phase2-ggb-section {
    margin-top: var(--spacing-md);
}
.phase2-ggb-section h3 {
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}
.phase2-ggb-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}
.phase2-ggb-card {
    background: rgba(102, 126, 234, 0.06);
    border: 1px solid rgba(102, 126, 234, 0.2);
    border-radius: 10px;
    padding: var(--spacing-md);
    overflow: hidden;
}
.phase2-ggb-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 8px;
}
.phase2-ggb-title {
    font-weight: 600;
    color: var(--accent-color);
    font-size: var(--font-size-base);
}
.phase2-ggb-open {
    font-size: var(--font-size-sm);
    color: var(--accent-color);
    text-decoration: none;
}
.phase2-ggb-open:hover {
    text-decoration: underline;
}
.phase2-ggb-desc {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin: 0 0 10px 0;
    line-height: 1.45;
}
.phase2-ggb-embed {
    border-radius: 8px;
    overflow: hidden;
    background: #fff;
    max-width: 100%;
}
.phase2-ggb-embed iframe {
    display: block;
    border: none;
    width: 100%;
    min-height: 400px;
}

.skill-content-section {
    margin-bottom: var(--spacing-lg);
}

.skill-content-section h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.skill-content-section ul,
.skill-content-section ol {
    margin-left: var(--spacing-lg);
}

.skill-estimated-time {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-top: var(--spacing-md);
}

/* 丰富内容块：促进学习思维 */
.skill-think-block {
    background: rgba(102, 126, 234, 0.08);
    border-left: 4px solid var(--accent-color);
    padding: var(--spacing-sm) var(--spacing-md);
    margin-top: var(--spacing-sm);
    border-radius: 0 8px 8px 0;
}

.skill-think-prompt {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.06) 0%, rgba(118, 75, 162, 0.04) 100%);
    border-radius: 10px;
    padding: var(--spacing-md);
}

.skill-think-prompt h3 {
    color: var(--accent-color);
}

.skill-level-list {
    list-style: none;
    margin-left: 0;
}

.skill-level-list li {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
}

.skill-level-num {
    flex-shrink: 0;
    width: 22px;
    height: 22px;
    line-height: 22px;
    text-align: center;
    background: var(--accent-color);
    color: white;
    border-radius: 50%;
    font-size: 12px;
    font-weight: 600;
}

.skill-compare-box {
    background: #f5f5f5;
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-compare-box h3 {
    margin-bottom: var(--spacing-sm);
}

.skill-pitfall {
    background: #fff8e1;
    border: 1px solid #ffc107;
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-pitfall h3 {
    color: #e65100;
}

.skill-condition-box ul {
    margin-left: var(--spacing-md);
}

.skill-step-list {
    counter-reset: step;
    list-style: none;
    margin-left: 0;
}

.skill-step-list li {
    position: relative;
    padding-left: 28px;
    margin-bottom: var(--spacing-sm);
}

.skill-step-list li::before {
    counter-increment: step;
    content: counter(step);
    position: absolute;
    left: 0;
    width: 20px;
    height: 20px;
    line-height: 20px;
    text-align: center;
    font-size: 11px;
    font-weight: 700;
    color: var(--accent-color);
    background: rgba(102, 126, 234, 0.15);
    border-radius: 4px;
}

.skill-example-stub {
    border: 1px dashed rgba(102, 126, 234, 0.4);
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-checklist ul {
    list-style: none;
    margin-left: 0;
}

.skill-checklist li {
    padding-left: 24px;
    margin-bottom: 6px;
}

.skill-checklist li::before {
    content: "☐ ";
    margin-left: -24px;
    margin-right: 6px;
    color: var(--accent-color);
}

.skill-keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.skill-keyword-tag {
    display: inline-block;
    padding: 4px 10px;
    background: #e8eaf6;
    color: #3f51b5;
    border-radius: 999px;
    font-size: var(--font-size-sm);
}

.skill-formula-block .formula-display {
    padding: var(--spacing-sm) 0;
}

/* 前置/延伸、可联动 Skill、推荐下一步、难度提示 */
.skill-prereq-next {
    background: #f0f4ff;
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-prereq-next p {
    margin-bottom: var(--spacing-xs);
}

.skill-node-links {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 6px;
}

.skill-node-link {
    display: inline-block;
    padding: 4px 10px;
    background: white;
    color: var(--accent-color);
    border: 1px solid rgba(102, 126, 234, 0.4);
    border-radius: 6px;
    font-size: var(--font-size-sm);
    text-decoration: none;
    transition: background var(--transition-fast), border-color var(--transition-fast);
}

.skill-node-link:hover {
    background: rgba(102, 126, 234, 0.1);
    border-color: var(--accent-color);
}

.skill-related-skills .skill-related-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: var(--spacing-sm);
}

.skill-related-tag {
    padding: 4px 10px;
    background: #e8eaf6;
    color: #3f51b5;
    border-radius: 6px;
    font-size: var(--font-size-sm);
}

.skill-next-action {
    background: linear-gradient(135deg, rgba(76, 175, 80, 0.08) 0%, rgba(56, 142, 60, 0.06) 100%);
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-next-action h3 {
    color: #2e7d32;
}

.skill-difficulty-tip {
    background: #fff3e0;
    border: 1px solid #ffb74d;
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-difficulty-tip h3 {
    color: #e65100;
}

/* Skill 面板底部操作 */
.skill-panel-footer {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) 0;
    margin-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.skill-footer-btn {
    padding: 8px 16px;
    font-size: var(--font-size-sm);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: white;
    color: var(--text-primary);
    cursor: pointer;
    transition: background var(--transition-fast), border-color var(--transition-fast);
}

.skill-footer-btn:hover {
    background: var(--secondary-bg);
    border-color: var(--accent-color);
}

.skill-footer-primary {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.skill-footer-primary:hover {
    background: #5568d3;
    border-color: #5568d3;
    color: white;
}

/* 侧栏：当前节点 · 去运用 */
.skill-current-node-block {
    margin-top: var(--spacing-sm);
    padding-top: var(--spacing-sm);
    border-top: 1px solid rgba(102, 126, 234, 0.2);
}

.skill-current-node-block.hidden {
    display: none !important;
}

.skill-current-node-label {
    font-size: 11px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 2px;
}

.skill-current-node-name {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.skill-apply-now-btn {
    width: 100%;
    padding: 8px 12px;
    font-size: var(--font-size-sm);
    background: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.skill-apply-now-btn:hover {
    background: #5568d3;
}

/* ========== 依据节点类型的 Skill 交互增强 ========== */
.skill-interactive-desc {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.skill-interactive-details {
    margin-top: var(--spacing-xs);
    border-radius: 6px;
    overflow: hidden;
}

.skill-interactive-details summary {
    padding: 8px 12px;
    background: rgba(102, 126, 234, 0.08);
    cursor: pointer;
    font-weight: 500;
    list-style: none;
    border-radius: 6px;
    margin-bottom: 4px;
}

.skill-interactive-details summary::-webkit-details-marker {
    display: none;
}

.skill-interactive-details summary::before {
    content: "▶ ";
    font-size: 10px;
}

.skill-interactive-details[open] summary::before {
    content: "▼ ";
}

.skill-interactive-details p {
    padding: 8px 12px 12px;
    margin: 0;
    font-size: var(--font-size-sm);
}

.skill-check-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.skill-check-item {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    cursor: pointer;
    font-size: var(--font-size-sm);
    padding: 6px 0;
}

.skill-check-input {
    flex-shrink: 0;
    margin-top: 2px;
    accent-color: var(--accent-color);
}

.skill-check-item:has(.skill-check-input:checked) {
    color: var(--text-secondary);
}

.skill-interactive-concept {
    background: rgba(63, 81, 181, 0.04);
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-interactive-theorem .skill-interactive-details {
    margin-bottom: 8px;
}

.skill-interactive-theorem {
    background: rgba(194, 24, 91, 0.04);
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-interactive-method {
    background: rgba(46, 125, 50, 0.04);
    border-radius: 8px;
    padding: var(--spacing-md);
}

.skill-interactive-application .skill-interactive-details {
    margin-bottom: 8px;
}

.skill-interactive-application {
    background: rgba(21, 101, 192, 0.04);
    border-radius: 8px;
    padding: var(--spacing-md);
}

.detail-panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    background-color: var(--secondary-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 10;
}

.detail-panel-header h2 {
    font-size: var(--font-size-xl);
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
    padding: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.detail-panel-content {
    padding: var(--spacing-lg);
}

.detail-section {
    margin-bottom: var(--spacing-lg);
}

.detail-section h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.detail-section p {
    line-height: 1.6;
    color: var(--text-secondary);
}

/* 所属学域：学域色块与核心思想 */
.detail-section--domain .detail-domain-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}
.detail-domain-block {
    border-left: 4px solid var(--domain-accent, #999);
    padding: var(--spacing-sm) var(--spacing-md);
    background: rgba(0, 0, 0, 0.04);
    border-radius: 0 8px 8px 0;
}
.detail-domain-header {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}
.detail-domain-idea {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    line-height: 1.4;
    margin: 0;
}

.formula-display {
    background-color: var(--secondary-bg);
    padding: var(--spacing-md);
    border-radius: 8px;
    margin: var(--spacing-md) 0;
    overflow-x: auto;
}

.skill-list, .scenario-list, .prerequisite-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.skill-item, .scenario-item, .prerequisite-item {
    padding: var(--spacing-md);
    background-color: var(--secondary-bg);
    border-radius: 8px;
    border-left: 3px solid var(--accent-color);
    transition: all var(--transition-fast);
}

.skill-item:hover, .scenario-item:hover, .prerequisite-item:hover {
    background-color: var(--hover-bg);
    transform: translateX(4px);
}

.skill-item a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
}

.skill-item a:hover {
    text-decoration: underline;
}

/* ========== Skills 运用 突出样式 ========== */
.detail-section.skills-apply-section {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.08) 0%, rgba(118, 75, 162, 0.06) 100%);
    border: 1px solid rgba(102, 126, 234, 0.35);
    border-radius: 10px;
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
}

.skills-apply-section h3 {
    color: var(--accent-color);
    margin-bottom: var(--spacing-xs);
}

.skills-apply-desc {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

/* ========== 学习数据导出（本机） ========== */
.learning-data-section .skills-hint-text {
    margin-top: 6px;
}

.learning-data-actions {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 10px;
}

.learning-data-btn {
    width: 100%;
    text-align: center;
}

.learning-data-btn--danger {
    background: #ffffff;
    color: #b42318;
    border: 1px solid rgba(180, 35, 24, 0.35);
}

.learning-data-btn--danger:hover {
    background: rgba(180, 35, 24, 0.06);
    border-color: rgba(180, 35, 24, 0.55);
}

/* Mastery demo panel */
.mastery-demo-section {
    background: linear-gradient(135deg, rgba(76, 175, 80, 0.08) 0%, rgba(102, 126, 234, 0.07) 100%);
    border: 1px solid rgba(76, 175, 80, 0.35);
    border-radius: 8px;
    padding: var(--spacing-sm) var(--spacing-md);
}

.mastery-unlocked-box {
    font-size: var(--font-size-sm);
    color: var(--sidebar-text);
    margin-bottom: var(--spacing-sm);
}

.mastery-source-controls {
    display: grid;
    gap: 6px;
    margin-bottom: var(--spacing-sm);
}

.mastery-source-controls label {
    font-size: var(--font-size-sm);
    color: var(--sidebar-text);
}

.mastery-meta-box {
    font-size: 11px;
    color: rgba(236, 240, 241, 0.95);
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 6px;
    padding: 6px 8px;
    line-height: 1.4;
}

.mastery-schema-hint summary {
    cursor: pointer;
    font-size: var(--font-size-sm);
    color: var(--sidebar-text);
}

.mastery-schema-hint pre {
    margin-top: 6px;
    font-size: 11px;
    color: #dff9fb;
    background: rgba(0, 0, 0, 0.25);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 6px;
    padding: 8px;
    white-space: pre-wrap;
}

.mastery-task-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: var(--spacing-sm);
}

.mastery-task-item {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 2px 8px;
    align-items: center;
    padding: 6px 8px;
    border-radius: 6px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.12);
    cursor: pointer;
}

.mastery-task-item input {
    grid-row: span 2;
}

.mastery-task-name {
    font-size: var(--font-size-sm);
}

.mastery-task-desc {
    grid-column: 2;
    font-size: 11px;
    color: rgba(236, 240, 241, 0.85);
}

.mastery-task-item.is-completed {
    border-color: rgba(139, 195, 74, 0.9);
    background: rgba(139, 195, 74, 0.15);
}

.mastery-task-item.is-unlocked {
    border-color: rgba(79, 172, 254, 0.75);
}

.mastery-task-item.is-locked {
    opacity: 0.6;
}

.mastery-table-wrap {
    margin-bottom: var(--spacing-sm);
    overflow-x: auto;
}

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

.mastery-table th,
.mastery-table td {
    text-align: left;
    padding: 4px 6px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
    color: var(--sidebar-text);
}

.mastery-progress {
    width: 100%;
    height: 6px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.2);
    overflow: hidden;
    margin-bottom: 2px;
}

.mastery-progress-bar {
    display: block;
    height: 100%;
    background: linear-gradient(90deg, #8bc34a 0%, #4caf50 100%);
}

.mastery-progress-text {
    font-size: 11px;
    color: rgba(236, 240, 241, 0.9);
}

.mastery-dot-output {
    margin-top: var(--spacing-sm);
    width: 100%;
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    background: rgba(0, 0, 0, 0.2);
    color: #dff9fb;
    padding: var(--spacing-sm);
    font-family: Consolas, Monaco, monospace;
    font-size: 11px;
}

.mastery-actions {
    display: grid;
    grid-template-columns: 1fr;
    gap: 6px;
}

.mastery-demo-error {
    color: #ffcccb;
    font-size: var(--font-size-sm);
}

.skill-apply-list {
    gap: var(--spacing-sm);
}

.skill-apply-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    border-left-color: var(--accent-color);
}

.skill-apply-item .skill-apply-name {
    flex: 1;
    min-width: 0;
}

.skill-phase2-badge-inline {
    display: inline-block;
    font-size: 11px;
    padding: 1px 6px;
    border-radius: 6px;
    background: rgba(37, 99, 235, 0.12);
    color: #2563eb;
    font-weight: 500;
}

.skill-phase2-badge {
    flex-shrink: 0;
    font-size: 11px;
    padding: 2px 8px;
    border-radius: 999px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.15) 0%, rgba(99, 102, 241, 0.12) 100%);
    color: #2563eb;
    font-weight: 600;
}

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

.skill-apply-btn {
    flex-shrink: 0;
    padding: 4px 12px;
    font-size: var(--font-size-sm);
    background: var(--accent-color);
    color: white !important;
    border-radius: 999px;
    text-decoration: none !important;
    transition: background var(--transition-fast), transform var(--transition-fast);
}

.skill-apply-btn:hover {
    background: #5568d3;
    transform: scale(1.05);
}

/* 图谱节点：有 Skills 的节点视觉突出 */
.node.has-skills circle {
    stroke-width: 2.5px;
    filter: drop-shadow(0 0 6px rgba(102, 126, 234, 0.4));
}

.node.has-skills:hover circle {
    filter: brightness(1.1) drop-shadow(0 0 8px rgba(102, 126, 234, 0.5));
}

.node-skills-badge {
    fill: var(--accent-color);
    font-weight: 600;
}

/* 侧栏 Skills 运用 入口 */
.skills-hint-section {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.06) 0%, rgba(118, 75, 162, 0.04) 100%);
    border: 1px solid rgba(102, 126, 234, 0.2);
    border-radius: 8px;
    padding: var(--spacing-sm) var(--spacing-md);
}

.skills-hint-section h3 {
    margin-bottom: var(--spacing-xs);
}

.skills-hint-text {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.skills-hint-link {
    display: inline-block;
    font-size: var(--font-size-sm);
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.skills-hint-link:hover {
    color: #5568d3;
    text-decoration: underline;
}

/* 侧栏 真实问题建模学习内容 入口 */
.real-modeling-section {
    background: linear-gradient(135deg, rgba(0, 242, 254, 0.06) 0%, rgba(0, 200, 220, 0.04) 100%);
    border: 1px solid rgba(0, 242, 254, 0.25);
    border-radius: 8px;
    padding: var(--spacing-sm) var(--spacing-md);
}

.real-modeling-section h3 {
    margin-bottom: var(--spacing-xs);
}

.real-modeling-hint-text {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.real-modeling-link {
    display: inline-block;
    font-size: var(--font-size-sm);
    color: var(--domain-5-color);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.real-modeling-link:hover {
    color: #00c4d6;
    text-decoration: underline;
}

/* Learning Path Section */
.learning-path-section {
    background-color: var(--secondary-bg);
    padding: var(--spacing-lg);
    border-radius: 8px;
    border: 2px solid var(--accent-color);
}

.learning-path-description {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

.generate-path-btn {
    width: 100%;
    padding: var(--spacing-md);
    background: linear-gradient(135deg, var(--accent-color) 0%, #4facfe 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.3);
}

.generate-path-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

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

.learning-path-container {
    margin-top: var(--spacing-lg);
}

.closed-loop-actions {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--spacing-sm);
}

.closed-loop-btn {
    padding: 10px 12px;
    border: 1px solid rgba(102, 126, 234, 0.35);
    border-radius: 8px;
    background-color: white;
    cursor: pointer;
    font-size: var(--font-size-sm);
    transition: all var(--transition-fast);
}

.closed-loop-btn--primary {
    grid-column: 1 / -1;
    background: linear-gradient(135deg, var(--accent-color) 0%, #4facfe 100%);
    color: #fff;
    font-weight: 600;
    border-color: transparent;
}

.closed-loop-btn:hover {
    border-color: var(--accent-color);
    background-color: var(--secondary-bg);
}

.closed-loop-container {
    margin-top: var(--spacing-md);
}

.closed-loop-block {
    background: white;
    border-radius: 8px;
    border-left: 3px solid var(--accent-color);
    padding: var(--spacing-sm) var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.closed-loop-block ul {
    margin: 6px 0 0 16px;
}

.learning-path-summary {
    display: flex;
    justify-content: space-around;
    padding: var(--spacing-md);
    background-color: white;
    border-radius: 8px;
    margin-bottom: var(--spacing-lg);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.path-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
}

.path-stat-label {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.path-stat-value {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--accent-color);
}

.learning-path-steps {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.path-step {
    background-color: white;
    border-radius: 8px;
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    border-left: 4px solid var(--accent-color);
    position: relative;
}

.path-step:hover {
    background-color: var(--hover-bg);
    transform: translateX(4px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.path-step-start {
    border-left-color: #4CAF50;
}

.path-step-target {
    border-left-color: #FF9800;
    background: linear-gradient(90deg, rgba(255, 152, 0, 0.05) 0%, white 100%);
}

.path-step-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.path-step-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--accent-color) 0%, #4facfe 100%);
    color: white;
    border-radius: 50%;
    font-weight: 600;
    font-size: var(--font-size-base);
    flex-shrink: 0;
}

.path-step-title {
    font-weight: 600;
    font-size: var(--font-size-base);
    color: var(--text-primary);
}

.path-step-body {
    margin-left: 48px;
}

.path-step-reason {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm);
    background-color: var(--secondary-bg);
    border-radius: 6px;
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.path-step-icon {
    flex-shrink: 0;
}

.path-step-meta {
    display: flex;
    gap: var(--spacing-lg);
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.path-step-time, .path-step-difficulty {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.path-step-connector {
    text-align: center;
    font-size: 24px;
    color: var(--accent-color);
    margin: var(--spacing-sm) 0;
    animation: connectorPulse 2s ease-in-out infinite;
}

@keyframes connectorPulse {
    0%, 100% {
        opacity: 0.6;
        transform: translateY(0);
    }
    50% {
        opacity: 1;
        transform: translateY(2px);
    }
}

.learning-path-actions {
    margin-top: var(--spacing-lg);
    display: flex;
    justify-content: center;
}

.clear-path-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background-color: white;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.clear-path-btn:hover {
    background-color: var(--secondary-bg);
    border-color: var(--accent-color);
    color: var(--text-primary);
}

/* Loading Indicator */
.loading-indicator {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    z-index: 100;
}

.loading-indicator.hidden {
    display: none;
}

.loading-indicator.hidden {
    display: none;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--spacing-md);
}

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

/* Notification Toast */
.notification-toast {
    position: fixed;
    bottom: -100px;
    left: 50%;
    transform: translateX(-50%);
    background-color: rgba(0, 0, 0, 0.9);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    transition: bottom var(--transition-base);
    z-index: 1000;
    max-width: 500px;
}

.notification-toast.show {
    bottom: var(--spacing-lg);
}

/* Responsive Design */
@media (max-width: 768px) {
    .header-top {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .header-user-menu {
        width: 100%;
        justify-content: space-between;
    }
    
    .sidebar {
        position: absolute;
        left: 0;
        top: 0;
        height: 100%;
        transform: translateX(-100%);
        z-index: 100;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .sidebar-toggle {
        display: block;
    }
    
    .detail-panel {
        width: 100%;
        right: -100%;
    }
    
    .zoom-controls {
        top: var(--spacing-md);
        right: var(--spacing-md);
    }
    
    .zoom-btn {
        width: 36px;
        height: 36px;
        font-size: var(--font-size-base);
    }
}

@media (max-width: 480px) {
    .app-header {
        padding: var(--spacing-md);
    }
    
    .header-content h1 {
        font-size: var(--font-size-xl);
    }
    
    .header-content .subtitle {
        font-size: var(--font-size-sm);
    }
    
    .sidebar {
        width: 280px;
    }
}

/* Accessibility */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Focus Styles */
*:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

button:focus, a:focus, input:focus, select:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000;
        --text-secondary: #000;
    }
    
    .node circle {
        stroke-width: 3px;
    }
}

/* Reduced Motion Support */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}


/* Skills内容显示样式 */
.skill-tag.clickable {
    cursor: pointer;
    transition: all 0.2s ease;
}

.skill-tag.clickable:hover {
    background: #667eea;
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.3);
}

.skill-content-container {
    display: none;
    margin-top: 20px;
    padding: 20px;
    background: #f8fafc;
    border-radius: 8px;
    border: 1px solid #e2e8f0;
}

.skill-detail-content {
    animation: fadeIn 0.3s ease;
}

.skill-header {
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid #e2e8f0;
}

.skill-header h3 {
    margin: 0 0 10px 0;
    color: #667eea;
    font-size: 1.5em;
}

.skill-description {
    color: #64748b;
    margin: 10px 0;
    line-height: 1.6;
}

.skill-meta {
    display: flex;
    gap: 20px;
    margin-top: 15px;
    flex-wrap: wrap;
}

.skill-meta span {
    padding: 6px 12px;
    background: white;
    border-radius: 6px;
    font-size: 0.9em;
    color: #475569;
    border: 1px solid #e2e8f0;
}

.skill-section {
    margin: 25px 0;
}

.skill-section h4 {
    color: #334155;
    margin-bottom: 15px;
    font-size: 1.2em;
}

.learning-path {
    background: white;
    padding: 15px;
    margin-bottom: 15px;
    border-radius: 6px;
    border-left: 4px solid #667eea;
}

.learning-path h5 {
    margin: 0 0 8px 0;
    color: #1e293b;
}

.learning-path p {
    color: #64748b;
    margin: 8px 0;
    line-height: 1.5;
}

.path-meta {
    display: flex;
    gap: 15px;
    margin-top: 10px;
    font-size: 0.85em;
    color: #64748b;
}

.advanced-topic {
    background: white;
    padding: 15px;
    margin-bottom: 15px;
    border-radius: 6px;
    border-left: 4px solid #10b981;
}

.advanced-topic h5 {
    margin: 0 0 8px 0;
    color: #1e293b;
}

.advanced-topic p {
    color: #64748b;
    margin: 8px 0;
    line-height: 1.5;
}

.advanced-topic .formula {
    margin: 15px 0;
    padding: 15px;
    background: #f8fafc;
    border-radius: 4px;
    overflow-x: auto;
}

.exercises-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.exercise-item {
    background: white;
    padding: 15px;
    border-radius: 6px;
    border-left: 4px solid #f59e0b;
    transition: all 0.2s ease;
}

.exercise-item:hover {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    transform: translateX(4px);
}

.exercise-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.exercise-id {
    font-family: monospace;
    font-size: 0.85em;
    color: #64748b;
    background: #f1f5f9;
    padding: 4px 8px;
    border-radius: 4px;
}

.difficulty-badge {
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 0.8em;
    font-weight: bold;
}

.difficulty-badge.difficulty-2 {
    background: #bfdbfe;
    color: #1e40af;
}

.difficulty-badge.difficulty-3 {
    background: #fde68a;
    color: #92400e;
}

.difficulty-badge.difficulty-4 {
    background: #fecaca;
    color: #991b1b;
}

.difficulty-badge.difficulty-5 {
    background: #ddd6fe;
    color: #5b21b6;
}

.exercise-question {
    color: #1e293b;
    margin: 10px 0;
    line-height: 1.6;
}

.exercise-meta {
    display: flex;
    gap: 15px;
    margin-top: 10px;
    font-size: 0.85em;
    color: #64748b;
}

.more-exercises {
    text-align: center;
    padding: 15px;
    color: #64748b;
    font-style: italic;
}

.close-skill-btn {
    margin-top: 20px;
    padding: 10px 20px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1em;
    transition: all 0.2s ease;
}

.close-skill-btn:hover {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.skill-content-container .loading {
    text-align: center;
    padding: 40px;
    color: #64748b;
}

.skill-content-container .error {
    padding: 20px;
    background: #fee2e2;
    border: 1px solid #fecaca;
    color: #991b1b;
    border-radius: 6px;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 从 Flask 学习平台嵌入（?embed=1）时的顶栏提示 */
.webapp-embed-bar {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px 16px;
    padding: 8px 16px;
    background: linear-gradient(90deg, #1d3557 0%, #2a6f97 50%, #1d3557 100%);
    color: #f1faee;
    font-size: 13px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
    z-index: 200;
}

.webapp-embed-bar__text strong {
    color: #f4a261;
    font-weight: 600;
}

.webapp-embed-bar__link {
    color: #a8dadc;
    text-decoration: none;
    padding: 4px 10px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.08);
    transition: background var(--transition-fast), color var(--transition-fast);
}

.webapp-embed-bar__link:hover {
    background: rgba(232, 93, 78, 0.35);
    color: #fff;
}

/* ===== 资源关联面板样式 ===== */
.resource-section {
    margin-top: 20px;
    padding-top: 16px;
    border-top: 1px solid rgba(102,126,234,0.2);
}

.resource-section h3 {
    margin-bottom: 16px;
    color: #fff;
    font-size: 16px;
}

.resource-subsection {
    margin-bottom: 16px;
}

.resource-subsection h4 {
    font-size: 13px;
    color: #94a3b8;
    margin-bottom: 10px;
    font-weight: normal;
}

.resource-card {
    background: rgba(255,255,255,0.05);
    border-radius: 8px;
    padding: 12px;
    margin-bottom: 8px;
    cursor: pointer;
    transition: all 0.2s;
    border-left: 3px solid transparent;
}

.resource-card:hover {
    background: rgba(102,126,234,0.15);
    transform: translateX(4px);
}

.resource-card.video {
    border-left-color: #f97316;
}

.resource-card.interactive {
    border-left-color: #22c55e;
}

.resource-card.question {
    border-left-color: #8b5cf6;
}

.resource-card-title {
    color: #e2e8f0;
    font-size: 13px;
    margin-bottom: 6px;
}

.resource-card-meta {
    display: flex;
    gap: 12px;
    font-size: 11px;
    color: #64748b;
}

.quality-bar {
    width: 50px;
    height: 4px;
    background: rgba(255,255,255,0.1);
    border-radius: 2px;
    overflow: hidden;
}

.quality-fill {
    display: block;
    height: 100%;
    background: linear-gradient(90deg, #22c55e, #4ade80);
    border-radius: 2px;
}

/* Chapter Progress */
.chapter-progress-list {
    max-height: 300px;
    overflow-y: auto;
}

.chapter-progress-item {
    margin-bottom: 12px;
    padding: 8px;
    background: var(--bg-secondary, #f5f5f5);
    border-radius: 6px;
}

.chapter-progress-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 4px;
    font-size: 12px;
}

.chapter-name {
    font-weight: 500;
    color: var(--text-primary, #333);
}

.chapter-percent {
    color: var(--primary-color, #667eea);
    font-weight: 600;
}

.chapter-progress-bar {
    height: 6px;
    background: var(--border-color, #ddd);
    border-radius: 3px;
    overflow: hidden;
}

.chapter-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    border-radius: 3px;
    transition: width 0.3s ease;
}

.chapter-count {
    display: block;
    font-size: 11px;
    color: var(--text-secondary, #666);
    margin-top: 2px;
}