/* ===== bi-nances-g.com 币学堂 — 深色学术风 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --bg: #0f172a; --bg-card: #1e293b; --bg-card-hover: #263348; --bg-input: #334155;
  --accent: #f59e0b; --accent-hover: #d97706; --accent-light: rgba(245,158,11,.1);
  --text: #f1f5f9; --text2: #94a3b8; --text3: #64748b;
  --border: #334155; --radius: 8px;
}
html { font-size: 16px; scroll-behavior: smooth; }
body { font-family: -apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei","PingFang SC",sans-serif; background: var(--bg); color: var(--text); line-height: 1.75; }
a { color: var(--accent); text-decoration: none; transition: color .2s; }
a:hover { color: var(--accent-hover); }
img { max-width: 100%; height: auto; }
ul, ol { list-style: none; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* Top Banner */
.top-banner { background: linear-gradient(90deg,var(--accent),#d97706); color: #000; padding: 10px 0; font-size: .85rem; font-weight: 600; text-align: center; }
.top-banner .container { display: flex; justify-content: center; align-items: center; gap: 16px; flex-wrap: wrap; }
.top-banner a { color: #000; text-decoration: underline; }

/* Header */
.site-header { background: rgba(15,23,42,.95); backdrop-filter: blur(12px); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 100; }
.site-header .container { display: flex; align-items: center; height: 60px; gap: 24px; }
.site-logo { font-family: Georgia,"Noto Serif SC",serif; font-size: 1.3rem; font-weight: 700; color: var(--accent); white-space: nowrap; }
.site-logo:hover { color: var(--accent-hover); }
.main-nav { display: flex; gap: 20px; flex: 1; }
.main-nav a { color: var(--text2); font-size: .9rem; padding: 4px 0; border-bottom: 2px solid transparent; transition: all .2s; }
.main-nav a:hover { color: var(--text); border-bottom-color: var(--accent); }
.header-actions { display: flex; gap: 10px; align-items: center; }
.lang-select { font-size: .75rem; padding: 3px 8px; border-radius: 4px; border: 1px solid var(--border, #e5e7eb); background: var(--bg-input, #f5f5f5); color: var(--text3, #666); cursor: pointer; margin-right: 6px; outline: none; }
.lang-select:focus { border-color: var(--accent, #f0b90b); }

/* Buttons */
.btn { display: inline-flex; align-items: center; gap: 6px; padding: 8px 20px; border-radius: var(--radius); font-weight: 600; font-size: .875rem; cursor: pointer; transition: all .2s; border: none; text-decoration: none; }
.btn-primary { background: var(--accent); color: #000; }
.btn-primary:hover { background: var(--accent-hover); color: #000; }
.btn-outline { background: transparent; color: var(--accent); border: 1.5px solid var(--accent); }
.btn-outline:hover { background: var(--accent-light); color: var(--accent); }
.btn-sm { padding: 5px 14px; font-size: .8rem; }
.btn-lg { padding: 14px 32px; font-size: 1rem; border-radius: 10px; }

/* Hero */
.hero { position: relative; text-align: center; padding: 72px 20px 56px; background: linear-gradient(135deg,#0f172a 0%,#1e293b 50%,#0f172a 100%); border-bottom: 1px solid var(--border); overflow: hidden; }
.hero::before { content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%; background: radial-gradient(ellipse at 30% 50%,rgba(245,158,11,.06) 0%,transparent 60%); pointer-events: none; }
.hero h1 { font-family: Georgia,"Noto Serif SC",serif; font-size: 2.2rem; margin-bottom: 16px; position: relative; }
.hero-desc { font-size: 1.05rem; color: var(--text2); max-width: 640px; margin: 0 auto 28px; position: relative; }
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; position: relative; }
.hero-badge { display: inline-block; margin-top: 20px; font-size: .8rem; color: var(--text3); position: relative; }
.hero-badge strong { color: var(--accent); }

/* Content Layout */
.content-wrapper { display: grid; grid-template-columns: 1fr 320px; gap: 28px; margin: 32px 0; }
.main-column { min-width: 0; }
.section { margin-bottom: 36px; }
.section-title { font-family: Georgia,"Noto Serif SC",serif; font-size: 1.35rem; margin-bottom: 20px; padding-bottom: 12px; border-bottom: 2px solid var(--accent); display: inline-block; }

/* Post Card */
.post-list { display: flex; flex-direction: column; gap: 16px; }
.post-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; transition: all .25s; }
.post-card:hover { border-color: var(--accent); box-shadow: 0 0 20px rgba(245,158,11,.07); transform: translateY(-2px); }
.post-card h2, .post-card h3 { margin-bottom: 8px; font-family: Georgia,"Noto Serif SC",serif; }
.post-card h2 a, .post-card h3 a { color: var(--text); }
.post-card h2 a:hover, .post-card h3 a:hover { color: var(--accent); }
.post-card p { color: var(--text2); font-size: .9rem; line-height: 1.6; }
.post-meta { display: flex; align-items: center; gap: 12px; margin-top: 12px; font-size: .8rem; color: var(--text3); }

/* Post Detail */
.post-detail { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 40px; }
.post-header { margin-bottom: 24px; padding-bottom: 20px; border-bottom: 1px solid var(--border); }
.post-header h1 { font-family: Georgia,"Noto Serif SC",serif; font-size: 1.8rem; line-height: 1.35; margin-bottom: 12px; }
.post-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 8px; }
.author-box { display: flex; align-items: center; gap: 12px; padding: 14px 16px; margin: 16px 0; background: var(--accent-light); border-radius: var(--radius); border-left: 3px solid var(--accent); }
.author-avatar { width: 40px; height: 40px; border-radius: 50%; background: var(--accent); color: #000; display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 1rem; flex-shrink: 0; }
.author-name { font-weight: 600; font-size: .88rem; }
.author-desc { font-size: .78rem; color: var(--text2); }

/* Post Content */
.post-content { font-size: 1rem; line-height: 1.85; }
.post-content h2 { font-family: Georgia,"Noto Serif SC",serif; font-size: 1.35rem; margin: 36px 0 16px; padding: 10px 0 10px 16px; border-left: 4px solid var(--accent); color: var(--text); }
.post-content h3 { font-size: 1.1rem; margin: 24px 0 12px; color: var(--text); }
.post-content p { margin-bottom: 16px; color: var(--text2); }
.post-content ul, .post-content ol { margin: 12px 0 18px 24px; }
.post-content ul { list-style: disc; }
.post-content ol { list-style: decimal; }
.post-content li { margin-bottom: 8px; color: var(--text2); }
.post-content strong { color: var(--text); }
.post-content blockquote { background: var(--accent-light); border-left: 4px solid var(--accent); padding: 16px 20px; margin: 20px 0; border-radius: 0 var(--radius) var(--radius) 0; }
.post-content blockquote p { margin-bottom: 0; color: var(--text); }
.post-content a { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }
.post-content a:hover { color: var(--accent-hover); }

/* CTA Card */
.cta-card { background: linear-gradient(135deg,#1a1c2e,#1e293b); border: 1.5px solid var(--accent); border-radius: 12px; padding: 28px; text-align: center; margin: 28px 0; position: relative; overflow: hidden; }
.cta-card::before { content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px; background: linear-gradient(90deg,var(--accent),#d97706,var(--accent)); }
.cta-card h3 { font-family: Georgia,"Noto Serif SC",serif; font-size: 1.15rem; margin-bottom: 8px; }
.cta-card p { color: var(--text2); margin-bottom: 16px; font-size: .9rem; }
.cta-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.cta-note { display: block; margin-top: 12px; font-size: .75rem; color: var(--text3); }
.ref-code { display: inline-block; margin-top: 8px; background: var(--bg-input); padding: 4px 14px; border-radius: 4px; font-family: monospace; font-size: .85rem; color: var(--accent); letter-spacing: 1px; }

/* Download CTA */
.download-cta { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; margin: 20px 0; }
.download-cta h4 { font-size: .95rem; margin-bottom: 12px; color: var(--text); }
.download-btns { display: flex; gap: 10px; flex-wrap: wrap; }

/* Sidebar */
.sidebar { display: flex; flex-direction: column; gap: 20px; }
.sidebar-widget { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; }
.sidebar-widget h3 { font-size: .95rem; margin-bottom: 14px; padding-bottom: 10px; border-bottom: 1px solid var(--border); color: var(--text); }
.sidebar-cta { background: linear-gradient(135deg,#1a1c2e,#0f172a); border-color: var(--accent); text-align: center; }
.sidebar-cta h3 { color: var(--accent); border-bottom-color: rgba(245,158,11,.3); }
.sidebar-cta p { font-size: .85rem; color: var(--text2); margin-bottom: 12px; }
.sidebar-cta .btn { width: 100%; justify-content: center; margin-bottom: 8px; }
.popular-posts li { padding: 8px 0; border-bottom: 1px solid var(--border); font-size: .875rem; }
.popular-posts li:last-child { border: none; }
.popular-posts a { color: var(--text2); }
.popular-posts a:hover { color: var(--accent); }

/* Tags */
.tag { display: inline-block; background: var(--bg-input); color: var(--text2); padding: 3px 12px; border-radius: 4px; font-size: .75rem; transition: all .2s; }
.tag:hover { background: var(--accent); color: #000; }
.tag-cloud { display: flex; flex-wrap: wrap; gap: 8px; }
.tag-index { display: grid; grid-template-columns: repeat(auto-fill,minmax(200px,1fr)); gap: 14px; margin: 24px 0; }
.tag-card { display: flex; justify-content: space-between; align-items: center; background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 20px; color: var(--text); transition: all .2s; }
.tag-card:hover { border-color: var(--accent); box-shadow: 0 0 12px rgba(245,158,11,.08); }
.tag-count { font-size: .8rem; color: var(--text3); }

/* Breadcrumb */
.breadcrumb { font-size: .85rem; color: var(--text3); padding: 16px 0; }
.breadcrumb a { color: var(--text2); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .sep { margin: 0 8px; opacity: .5; }
.breadcrumb .current { color: var(--text); }

/* Related Posts */
.related-posts { margin: 40px 0; padding-top: 32px; border-top: 1px solid var(--border); }
.related-posts h2 { font-family: Georgia,"Noto Serif SC",serif; margin-bottom: 20px; font-size: 1.25rem; }
.post-grid { display: grid; grid-template-columns: repeat(auto-fill,minmax(280px,1fr)); gap: 16px; }

/* Page Content */
.page-content { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 40px; margin: 24px 0; line-height: 1.85; }
.page-content h1 { font-family: Georgia,"Noto Serif SC",serif; margin-bottom: 24px; font-size: 1.7rem; }
.page-content h2 { font-size: 1.25rem; margin: 28px 0 12px; color: var(--accent); }
.page-content h3 { font-size: 1.05rem; margin: 20px 0 10px; }
.page-content p { margin-bottom: 14px; color: var(--text2); }
.page-content ul { margin: 10px 0 16px 24px; list-style: disc; }
.page-content li { margin-bottom: 6px; color: var(--text2); }
.page-content strong { color: var(--text); }

/* Footer */
.site-footer { background: #080c14; border-top: 1px solid var(--border); padding: 48px 0 24px; margin-top: 48px; font-size: .875rem; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 28px; margin-bottom: 28px; }
.footer-section h4 { color: var(--accent); margin-bottom: 14px; font-size: .95rem; }
.footer-section p { color: var(--text3); font-size: .85rem; line-height: 1.6; }
.footer-section ul li { margin-bottom: 8px; }
.footer-section a { color: var(--text2); }
.footer-section a:hover { color: var(--accent); }
.footer-download { margin-top: 12px; }
.risk-warning { background: rgba(239,68,68,.08); border: 1px solid rgba(239,68,68,.2); border-radius: var(--radius); padding: 14px 18px; font-size: .8rem; color: #fca5a5; line-height: 1.6; margin-bottom: 20px; }
.footer-bottom { border-top: 1px solid var(--border); padding-top: 18px; text-align: center; font-size: .78rem; color: var(--text3); }

/* 404 */
.error-page { text-align: center; padding: 100px 20px; }
.error-page h1 { font-size: 5rem; color: var(--accent); margin-bottom: 16px; font-family: Georgia,serif; }
.error-page p { margin-bottom: 24px; color: var(--text2); font-size: 1.1rem; }

/* Responsive */
@media (max-width: 900px) { .content-wrapper { grid-template-columns: 1fr; } .sidebar { order: 2; } .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 600px) { .hero { padding: 48px 16px 40px; } .hero h1 { font-size: 1.5rem; } .post-detail { padding: 20px; } .footer-grid { grid-template-columns: 1fr; } .main-nav { display: none; } .header-actions .btn-outline { display: none; } .tag-index { grid-template-columns: 1fr 1fr; } .lang-select { margin-right: 2px; font-size: .65rem; } }
/* TOC */
.toc{background:var(--bg-card);border:1px solid var(--border);border-radius:8px;padding:20px 24px;margin:20px 0 24px}
.toc-heading{font-size:1rem;font-weight:700;margin:0 0 12px;color:var(--heading)}
.toc-list{margin:0;padding-left:20px;list-style:decimal}
.toc-list li{margin:6px 0}
.toc-list a{color:var(--primary);text-decoration:none;font-size:.9rem}
.toc-list a:hover{text-decoration:underline}
/* Reading time & update */
.meta-reading,.meta-updated{font-size:.85rem;color:var(--text2,#64748b);margin-left:12px}
.meta-reading::before{content:"";margin-right:4px}