/* 学堂沿用全站纸色、墨绿和朱红，正文使用阅读宽度，目录与例题层次独立。 */
.academy-shell{max-width:1180px;margin:auto;padding:clamp(28px,5vw,64px) clamp(18px,4vw,36px)}
.academy-hero{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(270px,1fr);gap:clamp(32px,6vw,80px);align-items:center;padding:12px 0 54px}
.academy-hero h1{font-size:clamp(2rem,4vw,3.8rem);letter-spacing:-.035em;line-height:1.1;margin:16px 0 28px}
.academy-lead{font-family:Georgia,"Noto Serif SC","Songti SC",serif;font-size:clamp(1.6rem,3vw,2.5rem);line-height:1.5;margin:0 0 18px}
.academy-hero .muted{max-width:42ch;line-height:1.9}.academy-lesson{background:var(--ink);color:var(--paper);padding:clamp(24px,4vw,44px);border-top:4px solid var(--red)}
.academy-lesson-label{font-size:11px;letter-spacing:.12em;color:#d8d8bf}.academy-equation{display:grid;font-family:Georgia,serif;font-size:clamp(2.2rem,4vw,3.4rem);line-height:1.35;margin:25px 0}
.academy-equation small{font-size:.55em;color:#d4d7bc}.academy-equation strong{border-top:1px solid #677265;margin-top:10px;padding-top:10px;font-weight:400;color:#edd3a0}
.academy-lesson p{font-size:13px;line-height:1.9;color:#cbd1c1}.academy-lesson a{display:inline-block;margin-top:14px;text-underline-offset:5px;font-size:14px}
.academy-topics{margin:0 0 40px;padding:16px 0;border-block:1px solid var(--line);gap:12px 30px;flex-wrap:wrap;justify-content:flex-start}
.academy-topics a{font-size:14px}.academy-topics span{font-size:11px;font-weight:400;margin-left:10px;color:var(--muted)}
.academy-category{scroll-margin-top:24px;margin-bottom:42px}.academy-section-heading{display:flex;gap:12px;justify-content:space-between;align-items:center;margin-bottom:16px}
.academy-section-heading h2{margin:0;font-size:20px}.academy-section-heading>span{color:var(--muted);font-size:10px;letter-spacing:.13em}
.academy-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.academy-card{padding:24px 26px;background:var(--card);border:1px solid var(--line);border-top:2px solid var(--ink)}
.academy-card:only-child{grid-column:1/-1}.academy-card-meta,.academy-card-foot{display:flex;justify-content:space-between;gap:12px;font-size:12px;color:var(--muted)}
.academy-card-meta>span:first-child{color:var(--red)}.academy-card h3{font-size:22px;line-height:1.5;margin:20px 0 12px}.academy-card h3 a{text-decoration:none}
.academy-card h3 a:hover{text-decoration:underline;text-underline-offset:5px}.academy-card h3 span{color:var(--red);white-space:nowrap}.academy-card p{line-height:1.9;color:var(--muted);font-size:14px;max-width:70ch}
.academy-card-foot{border-top:1px solid var(--line);padding-top:16px;margin-top:24px}.academy-editorial{font-size:13px;line-height:1.9;color:var(--muted);border-top:1px solid var(--line);padding-top:24px}
.academy-article-heading{max-width:850px;padding:28px 0 36px}.academy-article-heading h1{font-family:Georgia,"Noto Serif SC","Songti SC",serif;font-size:clamp(1.9rem,4vw,3.2rem);line-height:1.35;letter-spacing:-.025em;margin:16px 0 22px;text-wrap:pretty}
.academy-summary{font-size:18px;line-height:1.9;color:var(--muted);max-width:65ch}.academy-byline{display:flex;flex-wrap:wrap;gap:8px 22px;font-size:12px;color:var(--muted);margin-top:24px}
.academy-reading{display:grid;grid-template-columns:210px minmax(0,1fr);gap:clamp(28px,5vw,64px);border-top:1px solid var(--line);padding-top:32px;align-items:start}
.academy-toc{position:sticky;top:24px}.academy-toc nav{display:block;margin:0;width:auto}.academy-toc h2{font-size:13px;color:var(--muted);margin:0 0 18px}
.academy-toc ol{padding-left:22px;margin:0}.academy-toc li{padding:0 0 16px 4px;font-size:13px;color:var(--red)}.academy-toc a{font-weight:400;color:var(--ink);line-height:1.6}
.academy-prose{min-width:0;max-width:760px;font-size:16px;line-height:2}.academy-scope{margin:0 0 34px;padding-left:18px;border-left:2px solid var(--line);color:var(--muted);font-size:13px;line-height:1.8}
.academy-prose-section{scroll-margin-top:24px;margin-bottom:38px}.academy-prose h2{font-size:24px;line-height:1.5;margin:0 0 20px}.academy-prose p{margin:0 0 18px}
.academy-example{margin:24px 0;padding:22px 24px;background:#e9ede2;border-left:3px solid #376346}.academy-example h3{margin:0 0 10px;font-size:15px}.academy-example p{font-size:15px;margin:0}
.academy-table-wrap{overflow-x:auto;margin:24px 0}.academy-prose table{border-collapse:collapse;width:100%;font-size:14px;line-height:1.7}.academy-prose th{letter-spacing:0;font-size:12px}.academy-prose td{vertical-align:top;min-width:90px}.academy-prose th,.academy-prose td{padding:12px}
.academy-takeaway{margin-top:40px;padding:26px;background:var(--ink);color:var(--paper)}.academy-takeaway h2{font-size:18px;color:#e7c795}.academy-takeaway .button-light{display:inline-block;background:var(--paper);color:var(--ink);font-size:14px;line-height:1.7;margin-top:8px}
.academy-sources{margin:32px 0;font-size:13px;line-height:1.8}.academy-sources h2{font-size:16px}.academy-sources ul{padding-left:20px}.academy-sources li{margin:8px 0;overflow-wrap:anywhere}.academy-sources a{text-underline-offset:3px}
.academy-related{border-top:1px solid var(--line);padding-top:32px;margin-top:48px}.academy-related>h2{font-size:22px;margin:0 0 22px}.academy-shell a:focus-visible{outline:2px solid var(--red);outline-offset:4px}
@media(max-width:760px){.academy-hero{grid-template-columns:1fr;gap:28px;padding-bottom:32px}.academy-lesson{padding:24px}.academy-equation{grid-template-columns:auto auto auto;align-items:center;gap:12px;font-size:2.1rem;margin:20px 0}.academy-equation strong{border:0;margin:0;padding:0}.academy-grid{grid-template-columns:1fr}.academy-reading{grid-template-columns:1fr;gap:24px}.academy-toc{position:static}.academy-toc ol{columns:2;column-gap:25px}.academy-toc li{break-inside:avoid}.academy-summary{font-size:16px}.academy-card{padding:22px}.academy-card h3{font-size:21px}.academy-prose h2{font-size:22px}.academy-byline{gap:8px 16px}}
@media(max-width:380px){.academy-equation{font-size:1.8rem;gap:8px}.academy-toc ol{columns:1}}