:root{--bg:#c7c7c7;--surface:#c7c7c7;--card:#bdbdbd;--accent:#000;--text:#000;--muted:#454545;--border:#999;--answer-bg:#d5d5d5;--answer-fg:#000;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Oxygen-Sans,Ubuntu,Cantarell,'Helvetica Neue',sans-serif;color:var(--text);background:var(--bg)}
*{box-sizing:border-box}body{margin:0;font-family:inherit;font-size:16px;font-weight:300;line-height:1.8;background:var(--bg);color:var(--text)}
a{color:inherit;text-underline-offset:3px}a:hover{text-decoration:none}a:focus-visible,button:focus-visible,summary:focus-visible{outline:2px solid #000;outline-offset:5px}
.site-header{max-width:1400px;margin:auto;padding:32px 48px 24px}.site-name{font-size:clamp(1.039rem,1.039rem + ((1vw - .2rem)*1.32),1.6rem);margin:0 0 16px;font-weight:300}.site-name a{text-decoration:none}.site-nav{display:flex;flex-wrap:wrap;gap:8px 24px;font-size:16px}.site-nav [aria-current]{font-weight:500;text-decoration:none}
.layout{display:grid;grid-template-columns:240px minmax(0,1fr);gap:48px;max-width:1400px;margin:0 auto;padding:16px 48px 64px;align-items:start}
.toc-panel{position:sticky;top:20px;max-height:calc(100vh - 40px);overflow:auto;font-size:14px;border-top:1px solid var(--border);padding-top:12px}.toc-panel summary{cursor:pointer;font-size:16px;font-weight:400;padding-bottom:12px}#toc a{display:block;padding:3px 0;overflow-wrap:anywhere;text-decoration:none;color:var(--muted)}#toc a:hover,#toc a.active{color:#000;text-decoration:underline}#toc h2{display:none}.toc-other{border-top:1px solid var(--border);margin-top:16px;padding-top:12px}
main{min-width:0;max-width:1000px}h1,h2,h3{font-weight:400;line-height:1.4}h1{font-size:28px;margin:0 0 12px}h2{font-size:20px;margin:42px 0 16px;border-top:1px solid var(--border);padding-top:20px;scroll-margin-top:24px;overflow-wrap:anywhere}h3{font-size:16px;margin:20px 0 8px}p{margin:10px 0}ol,ul{padding-left:26px}li{margin:6px 0}strong{font-weight:600}blockquote{margin:12px 0;color:var(--muted);font-size:14px}hr{border:0;border-top:1px solid var(--border);margin:32px 0}code{background:#d5d5d5;padding:2px 5px;overflow-wrap:anywhere}figure{margin:24px 0;text-align:center}figure img{max-width:100%;max-height:500px;height:auto;cursor:zoom-in}figcaption{font-size:14px;color:var(--muted);margin-top:6px}p.answer{border-left:2px solid #000;padding:10px 16px;background:var(--answer-bg);font-weight:400}table{display:block;overflow:auto;max-width:100%;border-collapse:collapse}th,td{padding:8px;border:1px solid var(--border)}
.part-nav{display:flex;flex-wrap:wrap;gap:8px 16px;font-size:14px;margin:16px 0 32px}.part-nav [aria-current]{font-weight:600;text-decoration:none}.part-label{font-size:14px;color:var(--muted);margin:0 0 12px}.site-footer{border-top:1px solid var(--border);margin-top:48px;padding-top:16px;font-size:14px;color:var(--muted)}
.index-main{max-width:1100px;margin:auto;padding:24px 48px 64px}.index-main h1{margin-top:8px}.part-list{list-style:none;padding:0;margin-top:32px;max-width:850px}.part-list li{border-top:1px solid var(--border);margin:0}.part-list a{display:grid;grid-template-columns:100px 1fr auto;gap:16px;padding:18px 0;text-decoration:none;align-items:baseline}.part-list a:hover .part-title{text-decoration:underline}.part-range,.part-count{font-size:14px;color:var(--muted)}
.image-unavailable{border:1px dashed var(--border);padding:24px 16px;font-size:14px;color:var(--muted)}
#lb{display:none;position:fixed;inset:0;background:rgba(0,0,0,.92);z-index:999;align-items:center;justify-content:center;cursor:zoom-out}#lb.on{display:flex}#lb img{max-width:94vw;max-height:90vh;object-fit:contain}#lb button{position:absolute;right:20px;top:16px;color:white;background:transparent;border:1px solid #aaa;font:inherit;padding:5px 14px;cursor:pointer}.skip-link{position:absolute;left:20px;top:-100px;background:#fff;padding:8px;z-index:1000}.skip-link:focus{top:8px}
@media(max-width:800px){.site-header{padding:24px 20px 20px}.site-nav{gap:6px 18px;font-size:14px}.layout{display:block;padding:8px 20px 40px}.toc-panel{position:static;max-height:none;margin-bottom:28px}.toc-panel[open] #toc{max-height:50vh;overflow:auto}.index-main{padding:16px 20px 40px}.part-list a{grid-template-columns:80px 1fr;gap:4px 8px}.part-count{grid-column:2}.part-range{overflow-wrap:anywhere}h1{font-size:25px}h2{font-size:18px}.site-footer{font-size:14px}}
/* Qbank v2: quiet scrollbars and compact reading navigation. */
*{scrollbar-width:thin;scrollbar-color:#898989 #c7c7c7}::-webkit-scrollbar{width:8px;height:8px}::-webkit-scrollbar-track{background:#c7c7c7}::-webkit-scrollbar-thumb{background:#898989;border:2px solid #c7c7c7;border-radius:8px}::-webkit-scrollbar-thumb:hover{background:#666}::-webkit-scrollbar-corner{background:#c7c7c7}
.site-header{padding-bottom:12px}.site-name{display:flex;align-items:baseline;gap:18px;margin:0}.brand-subtitle{font-size:14px;color:var(--muted)}.reader-title{font-size:20px;margin:0 0 14px}.reader-nav{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;font-size:14px;margin:0 0 28px;padding:12px 0;border-bottom:1px solid var(--border)}.reader-nav [aria-disabled]{color:#6b6b6b}.jump-form{display:flex;align-items:center;gap:10px}.jump-form select,.jump-form button{font:inherit;color:var(--text);background:var(--bg);border:1px solid #888;border-radius:3px;padding:6px 10px}.jump-form button{cursor:pointer}.question:first-of-type h2{margin-top:24px}.question h2{border-top:0;padding-top:0}.question{overflow-wrap:anywhere}.site-footer{margin-top:24px}.toc-panel{scrollbar-gutter:stable}
@media(max-width:800px){.site-header{padding-bottom:14px}.reader-nav{gap:10px}.jump-form{gap:6px}.jump-form label{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}.jump-form select,.jump-form button{padding:6px}.brand-subtitle{font-size:14px}.reader-title{font-size:18px}}
@media(forced-colors:active){*{scrollbar-color:auto}}