.wrap{max-width:960px;margin:0 auto;padding:15px 15px 80px}header.site{color:var(--muted);border-bottom:1px solid var(--line);text-align:center;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:10px;max-width:980px;margin:0 auto;padding:16px 20px;font-size:13px;line-height:normal;display:flex}header.site a{color:var(--accent);font-weight:700;text-decoration:none}.hero-section{text-align:center;margin:0 auto;padding:20px 0}h1{margin:0 0 6px;font-size:34px}.subtitle{color:var(--muted);font-size:17px;font-style:italic}h2{border-bottom:2px solid var(--accent);margin-top:44px;padding-bottom:6px;font-size:22px}h3{color:#333;margin-top:28px;font-size:17px}p{margin:14px 0}table{border-collapse:collapse;width:100%;margin:18px 0;font-family:Courier New,monospace;font-size:14px}th,td{border:1px solid var(--line);text-align:left;padding:8px 10px}th{background:var(--accent-bg);color:#5c3a10}.formula-box{background:var(--accent-bg);border:1px solid var(--line);border-left:4px solid var(--accent);margin:20px 0;padding:18px 20px;font-family:Courier New,monospace;font-size:16px}.example-box{border:1px solid var(--line);background:#f4f4f0;margin:16px 0;padding:16px 20px;font-size:14.5px}.example-box table{margin-top:10px}.note{background:#fff8e6;border:1px solid #f0dca0;margin:16px 0;padding:12px 16px;font-size:14px}.faq-item{margin-bottom:20px}.faq-q{margin-bottom:4px;font-weight:700}ol.refs{color:var(--muted);padding-left:20px;font-size:13.5px}ol.refs li{margin-bottom:8px}footer{border-top:1px solid var(--line);color:var(--muted);margin-top:60px;padding-top:18px;font-size:13px}.updated{color:#999;margin-top:6px;font-size:12px}.video-grid{grid-template-columns:repeat(4,1fr);gap:16px;margin:20px 0;display:grid}@media (max-width:680px){.video-grid{grid-template-columns:1fr}}.video-card{cursor:pointer;font-family:Georgia,serif}.video-thumb{aspect-ratio:16/9;border:1px solid var(--line);background:#000;position:relative;overflow:hidden}.video-thumb img{object-fit:cover;opacity:.85;width:100%;height:100%;display:block}.video-thumb iframe{border:0;width:100%;height:100%;display:block}.play-btn{color:#fff;background:#c4600fe6;border-radius:50%;justify-content:center;align-items:center;width:52px;height:52px;font-size:20px;display:flex;position:absolute;top:50%;left:50%;transform:translate(-50%,-50%)}.video-caption{margin-top:8px;font-size:13px;line-height:1.4}.email-footer{border-top:1px solid var(--line);margin-top:60px;padding-top:18px}.email-footer .label{margin-top:6px;font-size:12px}.about-disclaimer{border:1px dashed var(--accent);margin-top:36px;padding:14px 16px;font-size:11.5px}.about-disclaimer p{margin-bottom:8px;font-size:11.5px}.about-disclaimer p:last-child{margin-bottom:0}.about-disclaimer p:first-child{margin-top:0}