/* ============================================
   通用科普文章样式 v2.0 - Markdown实时渲染版
   支持深色/浅色主题 + 完整Markdown语法
   ============================================ */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-muted: #adb5bd;
    --color-accent: #4f46e5;
    --color-accent-light: #818cf8;
    --color-accent-dark: #3730a3;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-info: #3b82f6;
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --border-color: #e5e7eb;
    --border-radius-sm: 6px;
    --border-radius-md: 10px;
    --border-radius-lg: 16px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
}

[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-tertiary: #404040;
    --text-primary: #f5f5f5;
    --text-secondary: #b0b0b0;
    --text-muted: #808080;
    --border-color: #404040;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.7; color: var(--text-primary); background-color: var(--bg-primary);
    transition: background-color var(--transition-base), color var(--transition-base);
}

.progress-bar {
    position: fixed; top: 0; left: 0; width: 0%; height: 4px;
    background: var(--gradient-primary); z-index: 9999;
    transition: width 0.1s ease; box-shadow: 0 0 10px rgba(102, 126, 234, 0.5);
}

.navbar {
    position: sticky; top: 0; background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color); z-index: 1000;
    box-shadow: var(--shadow-sm);
}
.nav-container {
    max-width: 1200px; margin: 0 auto; padding: var(--spacing-sm) var(--spacing-md);
    display: flex; justify-content: space-between; align-items: center;
}
.nav-logo {
    font-size: 1.25rem; font-weight: 700;
    background: var(--gradient-primary); -webkit-background-clip: text;
    -webkit-text-fill-color: transparent; background-clip: text;
    text-decoration: none !important;
}
.nav-menu { display: flex; gap: var(--spacing-sm); }
.nav-toggle, .theme-toggle {
    background: transparent; border: 1px solid var(--border-color);
    padding: 0.5rem 1rem; border-radius: var(--border-radius-sm);
    cursor: pointer; font-size: 1.2rem; transition: all var(--transition-base);
}
.nav-toggle:hover, .theme-toggle:hover {
    background-color: var(--bg-secondary); transform: translateY(-2px);
}

.sidebar {
    position: fixed; left: -300px; top: 60px; width: 280px;
    height: calc(100vh - 60px); background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color); padding: var(--spacing-md);
    overflow-y: auto; transition: left var(--transition-base); z-index: 999;
    box-shadow: var(--shadow-lg);
}
.sidebar.active { left: 0; }
.sidebar-content h3 { margin-bottom: var(--spacing-md); color: var(--text-primary); font-size: 1.1rem; }
.catalog { list-style: none; }
.catalog li { margin-bottom: var(--spacing-sm); }
.catalog a {
    display: block; color: var(--text-secondary); text-decoration: none;
    padding: 0.5rem 0.75rem; border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast); font-size: 0.95rem;
}
.catalog a:hover { color: var(--color-accent); background-color: var(--bg-tertiary); padding-left: 1rem; }
.catalog a.active { color: var(--color-accent); background-color: var(--bg-tertiary); font-weight: 600; border-left: 3px solid var(--color-accent); }

.main-content { max-width: 900px; margin: 0 auto; padding: var(--spacing-xl) var(--spacing-md); }

.article-header {
    text-align: center; margin-bottom: var(--spacing-xl);
    padding: var(--spacing-xl); background: var(--gradient-primary);
    border-radius: var(--border-radius-lg); color: white;
    box-shadow: var(--shadow-lg);
}
.article-title {
    font-size: 2.5rem; font-weight: 800; margin-bottom: var(--spacing-sm);
    line-height: 1.2; text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}
.article-subtitle { font-size: 1.25rem; opacity: 0.95; margin-bottom: var(--spacing-md); }
.article-meta {
    display: flex; justify-content: center; gap: var(--spacing-md);
    flex-wrap: wrap; margin-bottom: var(--spacing-md); font-size: 0.9rem; opacity: 0.9;
}
.meta-item { display: flex; align-items: center; gap: 0.25rem; }
.article-tags { display: flex; justify-content: center; gap: 0.5rem; flex-wrap: wrap; margin-bottom: var(--spacing-md); }
.tag {
    display: inline-block; padding: 0.3rem 0.8rem;
    background: rgba(255,255,255,0.2); border: 1px solid rgba(255,255,255,0.4);
    border-radius: 20px; font-size: 0.85rem; backdrop-filter: blur(10px);
}
.article-actions { display: flex; justify-content: center; gap: var(--spacing-sm); flex-wrap: wrap; }
.btn-action {
    background-color: rgba(255, 255, 255, 0.2); border: 1px solid rgba(255, 255, 255, 0.4);
    color: white; padding: 0.6rem 1.5rem; border-radius: var(--border-radius-md);
    cursor: pointer; font-size: 0.95rem; font-weight: 600;
    transition: all var(--transition-base); backdrop-filter: blur(10px);
}
.btn-action:hover { background-color: rgba(255, 255, 255, 0.3); transform: translateY(-3px); box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2); }
.btn-action.active { background-color: rgba(255, 255, 255, 0.4); border-color: rgba(255, 255, 255, 0.6); }

/* ============================================
   Markdown 正文样式 (核心部分)
   ============================================ */
.markdown-body {
    line-height: 1.8; color: var(--text-secondary); font-size: 1.05rem;
}

.markdown-body > *:first-child { margin-top: 0; }
.markdown-body > *:last-child { margin-bottom: 0; }

/* 标题 */
.markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4,
.markdown-body h5, .markdown-body h6 {
    color: var(--text-primary); font-weight: 700; line-height: 1.4;
    margin-top: 2em; margin-bottom: 0.8em;
}
.markdown-body h1 { font-size: 2.2rem; border-bottom: 2px solid var(--color-accent); padding-bottom: 0.3em; }
.markdown-body h2 { font-size: 1.8rem; border-bottom: 2px solid var(--border-color); padding-bottom: 0.3em; }
.markdown-body h3 { font-size: 1.5rem; }
.markdown-body h4 { font-size: 1.25rem; }
.markdown-body h5 { font-size: 1.1rem; }
.markdown-body h6 { font-size: 1rem; color: var(--text-muted); }

/* 段落 */
.markdown-body p { margin-bottom: 1.2em; }

/* 链接 */
.markdown-body a {
    color: var(--color-accent-light); text-decoration: none;
    border-bottom: 1px solid transparent; transition: all var(--transition-fast);
}
.markdown-body a:hover { color: var(--color-accent); border-bottom-color: var(--color-accent); }

/* 粗体和斜体 */
.markdown-body strong { font-weight: 700; color: var(--text-primary); }
.markdown-body em { font-style: italic; }

/* 列表 */
.markdown-body ul, .markdown-body ol { margin-bottom: 1.2em; padding-left: 2em; }
.markdown-body li { margin-bottom: 0.5em; line-height: 1.7; }
.markdown-body li > ul, .markdown-body li > ol { margin-top: 0.5em; margin-bottom: 0.5em; }
.markdown-body ul { list-style-type: disc; }
.markdown-body ol { list-style-type: decimal; }
.markdown-body li::marker { color: var(--color-accent); font-weight: 600; }

/* 引用块 */
.markdown-body blockquote {
    margin: 1.5em 0; padding: 1em 1.5em;
    border-left: 5px solid var(--color-accent);
    background-color: var(--bg-secondary);
    border-radius: 0 var(--border-radius-md) var(--border-radius-md) 0;
    color: var(--text-secondary);
}
.markdown-body blockquote p:last-child { margin-bottom: 0; }
.markdown-body blockquote strong { color: var(--color-accent); }

/* 代码 */
.markdown-body code {
    padding: 0.2em 0.4em; margin: 0;
    font-size: 0.9em; font-family: 'Courier New', Consolas, Monaco, monospace;
    background-color: var(--bg-tertiary); border-radius: 4px;
    color: var(--color-danger);
}
.markdown-body pre {
    margin: 1.5em 0; padding: 1.2em;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    overflow-x: auto; line-height: 1.6;
}
.markdown-body pre code {
    padding: 0; margin: 0; font-size: 0.9em;
    background: transparent; border: none; border-radius: 0;
    color: inherit;
}

/* 表格 */
.markdown-body table {
    width: 100%; margin: 1.5em 0; border-collapse: collapse;
    background-color: var(--bg-secondary);
    border-radius: var(--border-radius-md); overflow: hidden;
    box-shadow: var(--shadow-sm);
}
.markdown-body thead { background: var(--gradient-primary); color: white; }
.markdown-body th, .markdown-body td {
    padding: 0.8em 1em; text-align: left; border-bottom: 1px solid var(--border-color);
}
.markdown-body th { font-weight: 600; }
.markdown-body tbody tr:last-child td { border-bottom: none; }
.markdown-body tbody tr { transition: background-color var(--transition-fast); }
.markdown-body tbody tr:hover { background-color: var(--bg-tertiary); }

/* 分隔线 */
.markdown-body hr {
    height: 2px; margin: 2em 0; padding: 0;
    background: var(--gradient-primary); border: none; border-radius: 1px;
}

/* 图片 */
.markdown-body img {
    max-width: 100%; height: auto; border-radius: var(--border-radius-md);
    margin: 1.5em 0; box-shadow: var(--shadow-md);
    display: block; margin-left: auto; margin-right: auto;
}

/* 删除线 */
.markdown-body del { text-decoration: line-through; color: var(--text-muted); }

/* 任务列表 */
.markdown-body input[type="checkbox"] {
    margin-right: 0.5em; accent-color: var(--color-accent);
}

/* 数学公式容器（如果使用KaTeX等） */
.markdown-body .katex-display { margin: 1.5em 0; overflow-x: auto; }

/* ============================================
   互动区域样式
   ============================================ */
.interaction-section {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    padding: var(--spacing-xl); border-radius: var(--border-radius-lg); margin-top: var(--spacing-xl);
}
[data-theme="dark"] .interaction-section {
    background: linear-gradient(135deg, #2d2d2d 0%, #404040 100%);
}
.interaction-section h2 { border: none; }

.comment-section {
    background-color: var(--bg-secondary); padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg); margin: var(--spacing-md) 0;
}
.comment-form { display: flex; flex-direction: column; gap: var(--spacing-sm); margin-bottom: var(--spacing-md); }
.comment-form input, .comment-form textarea {
    padding: var(--spacing-sm); border: 2px solid var(--border-color);
    border-radius: var(--border-radius-sm); background-color: var(--bg-primary);
    color: var(--text-primary); font-family: inherit;
}
.comment-form input:focus, .comment-form textarea:focus {
    outline: none; border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}
.comment-form textarea { resize: vertical; min-height: 80px; }
.btn-submit {
    background: var(--gradient-primary); color: white; border: none;
    padding: var(--spacing-sm) var(--spacing-md); border-radius: var(--border-radius-md);
    cursor: pointer; font-weight: 600; font-size: 1rem;
    transition: all var(--transition-base);
}
.btn-submit:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }

.help-resources {
    background-color: rgba(239, 68, 68, 0.1); border: 2px solid var(--color-danger);
    padding: var(--spacing-md); border-radius: var(--border-radius-md); margin: var(--spacing-md) 0;
}
.help-resources h3 { color: var(--color-danger); margin-bottom: var(--spacing-sm); }

.closing-message {
    text-align: center; padding: var(--spacing-xl);
    background: var(--gradient-primary); color: white;
    border-radius: var(--border-radius-lg); margin-top: var(--spacing-xl);
}
.closing-title { font-size: 1.5rem; font-weight: 700; margin-bottom: var(--spacing-md); }

.back-to-top {
    position: fixed; bottom: 30px; right: 30px; width: 50px; height: 50px;
    background: var(--gradient-primary); color: white; border: none;
    border-radius: 50%; font-size: 1.5rem; cursor: pointer;
    opacity: 0; visibility: hidden; transition: all var(--transition-base);
    box-shadow: var(--shadow-lg); z-index: 998;
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-5px); box-shadow: 0 20px 25px -5px rgba(0,0,0,0.3); }

.back-to-kepu {
    position: fixed; top: 16px; left: 16px; z-index: 9999;
    display: flex; align-items: center; gap: 6px;
    padding: 10px 16px; background: rgba(99, 102, 241, 0.9);
    color: #fff !important; text-decoration: none !important;
    border-radius: 24px; font-size: 14px; font-weight: 600;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    transition: all 0.3s ease; backdrop-filter: blur(8px);
}
.back-to-kepu:hover { background: rgba(99, 102, 241, 1); transform: translateY(-2px); box-shadow: 0 6px 16px rgba(0,0,0,0.2); }

.modal { display: none; position: fixed; z-index: 10000; left: 0; top: 0; width: 100%; height: 100%; background-color: rgba(0, 0, 0, 0.5); backdrop-filter: blur(5px); }
.modal.active { display: flex; justify-content: center; align-items: center; animation: fadeIn 0.3s ease; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

.modal-content {
    background-color: var(--bg-primary); padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg); max-width: 500px; width: 90%;
    position: relative; box-shadow: 0 20px 25px -5px rgba(0,0,0,0.3);
    animation: slideDown 0.3s ease;
}
@keyframes slideDown { from { transform: translateY(-50px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

.close { position: absolute; top: 10px; right: 20px; font-size: 2rem; color: var(--text-secondary); cursor: pointer; transition: color var(--transition-fast); }
.close:hover { color: var(--color-danger); }
.modal-content h3 { margin-bottom: var(--spacing-md); text-align: center; }
.share-buttons { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--spacing-sm); }
.share-btn {
    padding: var(--spacing-md); border: 2px solid var(--border-color);
    background-color: var(--bg-secondary); color: var(--text-primary);
    border-radius: var(--border-radius-md); cursor: pointer; font-size: 1rem;
    font-weight: 600; transition: all var(--transition-base);
}
.share-btn:hover { background-color: var(--bg-tertiary); transform: translateY(-2px); box-shadow: var(--shadow-md); }

.comment-item {
    background-color: var(--bg-tertiary); padding: var(--spacing-md);
    border-radius: var(--border-radius-md); margin-bottom: var(--spacing-sm);
    animation: slideIn 0.3s ease;
}
@keyframes slideIn { from { opacity: 0; transform: translateX(-20px); } to { opacity: 1; transform: translateX(0); } }
.comment-header { display: flex; justify-content: space-between; margin-bottom: var(--spacing-xs); }
.comment-name { font-weight: 600; color: var(--color-accent); }
.comment-time { font-size: 0.85rem; color: var(--text-muted); }
.comment-content { color: var(--text-secondary); line-height: 1.6; }

@media (min-width: 1024px) {
    .sidebar.active ~ .main-content { margin-left: 280px; }
}

@media (max-width: 768px) {
    html { font-size: 14px; }
    .article-title { font-size: 1.8rem; }
    .article-subtitle { font-size: 1rem; }
    .article-meta { flex-direction: column; gap: var(--spacing-xs); }
    .markdown-body h1 { font-size: 1.8rem; }
    .markdown-body h2 { font-size: 1.5rem; }
    table { font-size: 0.85rem; }
    th, td { padding: var(--spacing-xs); }
    .back-to-top { bottom: 20px; right: 20px; width: 45px; height: 45px; }
    .back-to-kepu { padding: 8px 12px; font-size: 13px; }
    .share-buttons { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .main-content { padding: var(--spacing-md) var(--spacing-sm); }
    .article-header { padding: var(--spacing-md); }
}

@media print {
    .navbar, .sidebar, .back-to-top, .progress-bar,
    .article-actions, .comment-section, .back-to-kepu { display: none !important; }
    .main-content { max-width: 100%; padding: 0; }
    .markdown-body { color: #000; }
}

::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg-secondary); }
::-webkit-scrollbar-thumb { background: var(--color-accent); border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: var(--color-accent-dark); }

::selection { background-color: var(--color-accent-light); color: white; }
::-moz-selection { background-color: var(--color-accent-light); color: white; }

/* 高亮.js代码高亮增强 */
.hljs { background: transparent !important; }
[data-theme="dark"] .hljs { background: var(--bg-tertiary) !important; }