/* ============================================
   全局主题系统 - 支持亮色/暗色模式
   ============================================ */
:root {
    /* 亮色模式 - 默认 */
    --bg-primary: #FFFFFF;
    --bg-secondary: #F9FAFB;
    --bg-tertiary: #F3F4F6;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);

    --text-primary: #1F2937;
    --text-secondary: #4B5563;
    --text-muted: #6B7280;
    --text-inverse: #FFFFFF;

    --border-color: #E5E7EB;
    --border-hover: #D1D5DB;

    --card-bg: #FFFFFF;
    --card-shadow: 0 20px 60px rgba(0,0,0,0.15);
    --card-shadow-sm: 0 4px 12px rgba(0,0,0,0.1);

    --accent-primary: #667eea;
    --accent-secondary: #764ba2;
    --accent-hover: #5568d3;

    /* 层级色 - 保持不变 */
    --color-level-1: #3B82F6;
    --color-level-2: #10B981;
    --color-level-3: #06B6D4;
    --color-level-4: #8B5CF6;
    --color-level-5: #F59E0B;
    --color-level-6: #EC4899;
    --color-level-0: #667eea;

    /* 层级浅色（用于背景） */
    --color-level-1-light: #DBEAFE;
    --color-level-2-light: #D1FAE5;
    --color-level-3-light: #CFFAFE;
    --color-level-4-light: #EDE9FE;
    --color-level-5-light: #FEF3C7;
    --color-level-6-light: #FCE7F3;

    /* 代码块 */
    --code-bg: #1F2937;
    --code-text: #E5E7EB;
}

/* 暗色模式 */
[data-theme="dark"] {
    --bg-primary: #0F172A;
    --bg-secondary: #1E293B;
    --bg-tertiary: #334155;
    --bg-gradient: linear-gradient(135deg, #1E293B 0%, #0F172A 100%);

    --text-primary: #F1F5F9;
    --text-secondary: #CBD5E1;
    --text-muted: #94A3B8;
    --text-inverse: #F1F5F9;

    --border-color: #334155;
    --border-hover: #475569;

    --card-bg: #1E293B;
    --card-shadow: 0 20px 60px rgba(0,0,0,0.5);
    --card-shadow-sm: 0 4px 12px rgba(0,0,0,0.3);

    --accent-primary: #818CF8;
    --accent-secondary: #A78BFA;
    --accent-hover: #6366F1;

    /* 层级浅色（暗色模式下） */
    --color-level-1-light: #1E3A8A;
    --color-level-2-light: #064E3B;
    --color-level-3-light: #164E63;
    --color-level-4-light: #4C1D95;
    --color-level-5-light: #78350F;
    --color-level-6-light: #831843;

    --code-bg: #020617;
    --code-text: #E2E8F0;
}

/* 平滑过渡 */
* {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

/* ============================================
   共享样式
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.8;
    color: var(--text-primary);
    background: var(--bg-gradient);
    min-height: 100vh;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 60px 20px;
}

header {
    text-align: center;
    /* header 永远坐在渐变（紫/深蓝）背景上，无论主题都需要浅色文字 */
    color: #FFFFFF;
    margin-bottom: 40px;
}

header h1,
header .subtitle,
header p {
    color: #FFFFFF;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

.card {
    background: var(--card-bg);
    color: var(--text-primary);
    border-radius: 16px;
    padding: 50px;
    box-shadow: var(--card-shadow);
    margin-bottom: 30px;
}

.card h2 {
    color: var(--accent-primary);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

.back-btn {
    display: inline-block;
    padding: 12px 30px;
    background: var(--card-bg);
    color: var(--accent-primary);
    border: 2px solid var(--accent-primary);
    text-decoration: none;
    border-radius: 30px;
    font-weight: 600;
    margin-bottom: 30px;
    transition: all 0.2s;
}

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

/* 头部双向导航：JS 运行时把单个 .back-btn 包成"上一页 | 首页" */
.nav-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 30px;
}

.nav-header .back-btn,
.nav-header .nav-back-prev {
    margin-bottom: 0;   /* 在 nav 里就不需要 margin 了 */
}

.nav-back-prev {
    display: inline-block;
    padding: 12px 24px;
    background: transparent;
    color: var(--text-secondary);
    border: 2px solid var(--border-color);
    text-decoration: none;
    border-radius: 30px;
    font-weight: 600;
    transition: all 0.2s;
    cursor: pointer;
}

.nav-back-prev:hover {
    background: var(--bg-secondary);
    color: var(--accent-primary);
    border-color: var(--accent-primary);
}

/* 移动端：按钮胶囊变紧凑，避免头部太占屏 */
@media (max-width: 600px) {
    .nav-header {
        gap: 8px;
    }
    .nav-header .back-btn,
    .nav-header .nav-back-prev {
        padding: 8px 16px;
        font-size: 0.92rem;
    }
}

.question {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--accent-secondary);
    padding: 15px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    margin: 20px 0;
}

.question a {
    color: inherit;
    text-decoration: none;
    transition: all 0.2s;
}

.question a:hover {
    color: var(--accent-primary);
    text-decoration: underline;
}

.btn {
    display: inline-block;
    padding: 14px 32px;
    background: linear-gradient(135deg, var(--accent-primary) 0%, var(--accent-secondary) 100%);
    color: white;
    text-decoration: none;
    border-radius: 30px;
    font-weight: 600;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

.btn-outline {
    background: var(--card-bg);
    color: var(--accent-primary);
    border: 2px solid var(--accent-primary);
}

.btn-outline:hover {
    background: var(--accent-primary);
    color: var(--text-inverse);
}

footer {
    text-align: center;
    color: var(--text-inverse);
    padding: 40px 0;
    opacity: 0.8;
    margin-top: 40px;
}

.coming-soon {
    text-align: center;
    padding: 60px 20px;
}

.coming-soon .icon {
    font-size: 4rem;
    margin-bottom: 20px;
}

.coming-soon h2 {
    color: var(--accent-primary);
    margin-bottom: 15px;
}

.coming-soon p {
    color: var(--text-muted);
    margin-bottom: 30px;
}

/* ============================================
   主题切换按钮
   ============================================ */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    background: var(--card-bg);
    border: 2px solid var(--accent-primary);
    color: var(--accent-primary);
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--card-shadow-sm);
    transition: all 0.2s;
}

.theme-toggle:hover {
    transform: scale(1.1) rotate(15deg);
    box-shadow: var(--card-shadow);
}

/* ============================================
   回到顶部按钮
   ============================================ */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 20px;
    z-index: 1000;
    background: linear-gradient(135deg, var(--accent-primary) 0%, var(--accent-secondary) 100%);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.4rem;
    display: none;
    align-items: center;
    justify-content: center;
    box-shadow: var(--card-shadow);
    transition: all 0.3s;
}

.back-to-top.visible {
    display: flex;
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 15px 35px rgba(102, 126, 234, 0.5);
}

/* ============================================
   阅读进度条
   ============================================ */
.reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-level-1), var(--color-level-2), var(--color-level-3), var(--color-level-4), var(--color-level-5), var(--color-level-6));
    z-index: 9999;
    width: 0%;
    transition: width 0.1s;
}

/* ============================================
   已阅读标记
   ============================================ */
.question-read-badge {
    display: inline-block;
    background: var(--color-level-2);
    color: white;
    font-size: 0.7rem;
    padding: 2px 8px;
    border-radius: 10px;
    margin-left: 8px;
    font-weight: 600;
}

/* ============================================
   搜索按钮 + 模态框
   ============================================ */
.search-toggle {
    position: fixed;
    bottom: 30px;
    right: 85px;
    z-index: 1000;
    background: var(--card-bg);
    border: 2px solid var(--accent-primary);
    color: var(--accent-primary);
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.3rem;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--card-shadow-sm);
    transition: all 0.2s;
}

.search-toggle:hover {
    transform: translateY(-4px) scale(1.1);
    box-shadow: var(--card-shadow);
}

.search-modal {
    position: fixed;
    inset: 0;
    z-index: 10000;
    display: none;
    align-items: flex-start;
    justify-content: center;
    padding: 60px 20px 20px;
}

.search-modal.open {
    display: flex;
    animation: search-fade-in 0.15s ease-out;
}

@keyframes search-fade-in {
    from { opacity: 0; }
    to { opacity: 1; }
}

.search-modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(15, 23, 42, 0.55);
    backdrop-filter: blur(3px);
    -webkit-backdrop-filter: blur(3px);
}

.search-modal-panel {
    position: relative;
    width: 100%;
    max-width: 680px;
    max-height: calc(100vh - 100px);
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: 0 25px 80px rgba(0, 0, 0, 0.35);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.search-input-wrap {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.search-input-icon {
    font-size: 1.2rem;
    color: var(--text-muted);
}

.search-input {
    flex: 1;
    border: none;
    outline: none;
    background: transparent;
    color: var(--text-primary);
    font-size: 1.05rem;
    padding: 6px 0;
    font-family: inherit;
}

.search-input::placeholder {
    color: var(--text-muted);
}

.search-close {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1.1rem;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 6px;
    transition: all 0.15s;
}

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

.search-status {
    padding: 10px 20px;
    font-size: 0.85rem;
    color: var(--text-muted);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.search-results {
    list-style: none;
    margin: 0;
    padding: 8px;
    overflow-y: auto;
    flex: 1;
    min-height: 0;
}

.search-item {
    border-radius: 10px;
    margin-bottom: 4px;
    cursor: pointer;
    transition: background 0.15s;
}

.search-item a {
    display: block;
    padding: 12px 14px;
    text-decoration: none;
    color: inherit;
}

.search-item:hover,
.search-item.active {
    background: var(--bg-secondary);
}

.search-item.active {
    outline: 2px solid var(--accent-primary);
    outline-offset: -2px;
}

.search-item-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 6px;
    flex-wrap: wrap;
}

.search-item-icon {
    font-size: 1.1rem;
}

.search-item-qid {
    display: inline-block;
    padding: 2px 8px;
    background: var(--accent-primary);
    color: white;
    border-radius: 10px;
    font-size: 0.75rem;
    font-weight: 700;
}

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

.search-badge {
    display: inline-block;
    padding: 2px 8px;
    background: var(--color-level-2);
    color: white;
    border-radius: 10px;
    font-size: 0.7rem;
    font-weight: 600;
}

.search-item-snippet {
    font-size: 0.88rem;
    line-height: 1.6;
    color: var(--text-secondary);
    /* 两行截断 */
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    word-break: break-word;
}

.search-item mark,
.search-item-title mark {
    background: rgba(245, 158, 11, 0.3);
    color: inherit;
    padding: 0 2px;
    border-radius: 3px;
    font-weight: 700;
}

[data-theme="dark"] .search-item mark,
[data-theme="dark"] .search-item-title mark {
    background: rgba(245, 158, 11, 0.35);
    color: #FCD34D;
}

.search-hint {
    padding: 10px 20px;
    font-size: 0.78rem;
    color: var(--text-muted);
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.search-hint kbd {
    display: inline-block;
    padding: 2px 6px;
    margin: 0 3px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-family: ui-monospace, monospace;
    font-size: 0.75rem;
    color: var(--text-secondary);
    box-shadow: 0 1px 0 var(--border-color);
}

@media (max-width: 700px) {
    .search-toggle {
        right: 65px;
        bottom: 20px;
        width: 40px;
        height: 40px;
        font-size: 1.1rem;
    }
    .search-modal {
        padding: 20px 10px;
    }
    .search-modal-panel {
        max-height: calc(100vh - 40px);
    }
}

/* ============================================
   Giscus 评论区外层容器
   ============================================ */
.comments-section {
    margin-top: 50px;
    padding-top: 30px;
    border-top: 2px solid var(--border-color);
}

.comments-section h2 {
    color: var(--accent-primary);
    font-size: 1.5rem;
}

.comments-section p {
    margin-bottom: 20px;
}

/* ============================================
   响应式
   ============================================ */
@media (max-width: 600px) {
    h1 {
        font-size: 1.8rem;
    }
    .card {
        padding: 30px 20px;
    }
    .theme-toggle {
        top: 10px;
        right: 10px;
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
    .back-to-top {
        bottom: 20px;
        right: 10px;
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
}

/* ============================================
   暗色模式全局兜底覆盖
   ---
   老文章（10 篇 P0 + 首页文章）里，把
   background: white / #F9FAFB / #EFF6FF 等浅色写死在
   内联 <style> 里。在暗色模式下会出现"浅色底 + 亮色字"
   撞色导致完全看不清。

   下面用 [data-theme="dark"] 提升特异性来覆盖它们，
   保持原有类名不变，不改动老文章。
   ============================================ */

/* 白色/浅灰卡片 → 暗色卡片 */
[data-theme="dark"] .content,
[data-theme="dark"] .article-content {
    background: var(--card-bg);
    color: var(--text-secondary);
    box-shadow: var(--card-shadow);
}

[data-theme="dark"] .article-content h2 {
    color: var(--accent-primary);
    border-bottom-color: var(--border-color);
}

[data-theme="dark"] .article-content h3 {
    color: var(--text-primary);
}

[data-theme="dark"] .article-content p,
[data-theme="dark"] .article-content li,
[data-theme="dark"] .content p,
[data-theme="dark"] .content li {
    color: var(--text-secondary);
}

[data-theme="dark"] .article-content strong,
[data-theme="dark"] .content strong {
    color: var(--text-primary);
}

/* 浅色装饰块 → 暗色变体 */
[data-theme="dark"] .diagram-box {
    background: var(--bg-secondary);
    border-color: var(--border-color);
    color: var(--text-secondary);
}

[data-theme="dark"] .highlight-box {
    background: var(--bg-secondary);
    border-left-color: var(--accent-primary);
    color: var(--text-secondary);
}

[data-theme="dark"] .highlight-box strong {
    color: var(--accent-primary);
}

/* Q7 的三大支柱、Q13 的层次卡片等浅灰色小卡片 */
[data-theme="dark"] .pillar,
[data-theme="dark"] .layer-item,
[data-theme="dark"] .tradeoff-card,
[data-theme="dark"] .case-study,
[data-theme="dark"] .balance-item,
[data-theme="dark"] .layer-card,
[data-theme="dark"] .live-demo-box,
[data-theme="dark"] .compare-card,
[data-theme="dark"] .compare-left,
[data-theme="dark"] .compare-right,
[data-theme="dark"] .journey-box,
[data-theme="dark"] .journey-tree,
[data-theme="dark"] .illusion-box,
[data-theme="dark"] .quote-box,
[data-theme="dark"] .side-card,
[data-theme="dark"] .side-left,
[data-theme="dark"] .side-right,
[data-theme="dark"] .stage-card,
[data-theme="dark"] .stage-1,
[data-theme="dark"] .stage-2,
[data-theme="dark"] .step-card,
[data-theme="dark"] .step-1,
[data-theme="dark"] .step-2,
[data-theme="dark"] .step-3,
[data-theme="dark"] .step-4,
[data-theme="dark"] .step-6,
[data-theme="dark"] .flow-step,
[data-theme="dark"] .tech-item,
[data-theme="dark"] .tree-item,
[data-theme="dark"] .timeline-item,
[data-theme="dark"] .timeline-content,
[data-theme="dark"] .tech-stack,
[data-theme="dark"] .three-pillars,
[data-theme="dark"] .layers-behind,
[data-theme="dark"] .request-flow,
[data-theme="dark"] .growth-stages,
[data-theme="dark"] .final-box,
[data-theme="dark"] .conway-diagram,
[data-theme="dark"] .button-demo {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border-color: var(--border-color);
}

/* 这些卡片里的标题 / 强调文字要能看清 */
[data-theme="dark"] .pillar h3,
[data-theme="dark"] .pillar h4,
[data-theme="dark"] .layer-item h4,
[data-theme="dark"] .tradeoff-card h4,
[data-theme="dark"] .case-study h4,
[data-theme="dark"] .compare-card h4,
[data-theme="dark"] .stage-card h4,
[data-theme="dark"] .side-card h4,
[data-theme="dark"] .journey-box h4,
[data-theme="dark"] .quote-box h4,
[data-theme="dark"] .illusion-box h4 {
    color: var(--text-primary);
}

[data-theme="dark"] .quote-author {
    color: var(--text-muted);
}

[data-theme="dark"] .layer-title {
    color: var(--accent-primary);
}

[data-theme="dark"] .live-demo {
    background: var(--bg-secondary);
    border-color: var(--accent-primary);
}

/* 白底的 "错误示例 / 常见误区" 红色框 */
[data-theme="dark"] .myth-box {
    background: rgba(239, 68, 68, 0.12);
    color: var(--text-secondary);
}

[data-theme="dark"] .myth-box h4 {
    color: #FCA5A5;
}

/* 首页主文章的 question 卡片 hover 背景 */
[data-theme="dark"] .question:hover {
    background: var(--bg-secondary);
}

[data-theme="dark"] .question {
    color: var(--accent-secondary);
    border-color: var(--border-color);
}

/* 首页 index.html 的卡片和层级块 */
[data-theme="dark"] .card {
    background: var(--card-bg);
    box-shadow: var(--card-shadow);
}

[data-theme="dark"] .card h2 {
    color: var(--accent-primary);
}

[data-theme="dark"] .layer {
    background: var(--bg-secondary);
    border-left-color: var(--accent-primary);
}

[data-theme="dark"] .layer:hover {
    background: var(--bg-tertiary);
}

[data-theme="dark"] .layer-content h3 {
    color: var(--text-primary);
}

[data-theme="dark"] .layer-content p {
    color: var(--text-muted);
}

[data-theme="dark"] .btn-outline {
    background: var(--card-bg);
    color: var(--accent-primary);
    border-color: var(--accent-primary);
}

/* 问题地图页 00-question-map.html */
[data-theme="dark"] .toc,
[data-theme="dark"] .section {
    background: var(--card-bg);
    box-shadow: var(--card-shadow);
}

[data-theme="dark"] .toc a {
    color: var(--text-secondary);
}

[data-theme="dark"] .toc a:hover {
    background: var(--bg-secondary);
    color: var(--accent-primary);
}

[data-theme="dark"] .question-item {
    background: var(--bg-secondary);
    border-left-color: var(--accent-secondary);
}

[data-theme="dark"] .question-item:hover {
    background: var(--bg-tertiary);
    border-left-color: var(--accent-primary);
}

[data-theme="dark"] .question-item a {
    color: var(--text-primary);
}

[data-theme="dark"] .question-item a:hover {
    color: var(--accent-primary);
}

[data-theme="dark"] .question-item .question-text {
    color: var(--text-secondary);
}

[data-theme="dark"] .question-item .question-status {
    color: var(--text-muted);
}

/* 相关问题药丸链接 */
[data-theme="dark"] .related-questions a {
    background: var(--bg-secondary);
    color: var(--accent-primary);
    border-color: var(--border-color);
}

[data-theme="dark"] .related-questions a:hover {
    background: var(--accent-primary);
    color: var(--text-inverse);
}

/* section-divider (🎯 第X层认知 分隔标题) 在暗色下的字色 */
[data-theme="dark"] .section-divider {
    color: var(--text-muted);
}

/* 通用兜底：任何硬编码 background:white 的容器里，
   直接子级 p / li / span 保底一个可读色（避免暗色下
   还有漏网的浅底 + 亮字组合）。特异性适中，不会误伤
   本来就是深色底的 emperor-box / try-box / code-block。 */
[data-theme="dark"] [style*="background: white"] p,
[data-theme="dark"] [style*="background:#fff"] p,
[data-theme="dark"] [style*="background: #fff"] p {
    color: #1F2937;
}