/* 刘钝 · 割圆：一部摊开的古算书。每屏一块“版”（四周双边）：左图、版心（鱼尾）、右史；
   数字用算筹摆。颜色取“丹青”：丹（朱砂）是割线与动作，青（石青）是圆与引文。 */
.c-liu-dun {
  --bg: #f2ede2; --paper: #fbf8f1; --ink: #1c1a16; --ink-2: #4b463e; --ink-3: #6e685c; --rule: rgba(28, 26, 22, .18);
  --acc: #c0391f; --acc-ink: #fff8f0; --dan: #c0391f; --dan-2: rgba(192, 57, 31, .12); --qing: #2b5b8f; --qing-2: rgba(43, 91, 143, .08);
  --bamboo: #d6b36a; --bamboo-2: #8f6b2a;
  --head: "Noto Serif SC", "Songti SC", serif; --body: "Noto Serif SC", "Songti SC", serif; --brush: "Ma Shan Zheng", "Noto Serif SC", serif;
  --bar-bg: rgba(242, 237, 226, .94); --chip-bg: rgba(251, 248, 241, .95); --chip-ring: #fbf8f1;
  background-color: var(--bg);
  background-image: radial-gradient(rgba(28, 26, 22, .035) 1px, transparent 1.2px);
  background-size: 7px 7px;
}
.c-liu-dun .dlg { --dlg-bg: #f1ebdf; --dlg-paper: #fffdf8; --dlg-ink: #1c1a16; --dlg-ink-2: #4b463e; --dlg-me: #2b5b8f; --dlg-me-ink: #fbf8f1; --dlg-acc: #b23519; }
.c-liu-dun .c3bar { border-bottom: 3px double rgba(28, 26, 22, .45); }
.c-liu-dun .c3bar__t a { letter-spacing: .06em; }
.c-liu-dun .c3bar__prog { background: var(--dan); height: 2px; }

/* 目录：一列小圆，圆里的正多边形一问比一问边多 */
.c-liu-dun .c3toc ol { gap: 4px; }
.c-liu-dun .c3toc a { gap: 6px; color: var(--ink-3); }
.c-liu-dun .c3toc a::after { display: none; }
.c-liu-dun .c3toc a b { order: 2; min-width: 2.4em; font-size: 12px; font-weight: 400; text-align: left; }
.c-liu-dun .c3toc a span { order: 1; font-size: 12.5px; color: var(--ink-2); }
.c-liu-dun .c3toc .ld-pi { order: 3; }
.ld-pi { flex: none; overflow: visible; }
.ld-pi circle { fill: none; stroke: currentColor; stroke-width: 1.1; opacity: .55; }
.ld-pi polygon { fill: none; stroke: currentColor; stroke-width: 1.1; stroke-linejoin: round; }
.c-liu-dun .c3toc a[aria-current="true"] { color: var(--dan); }
.c-liu-dun .c3toc a[aria-current="true"] .ld-pi polygon { fill: var(--dan-2); stroke-width: 1.5; }
.c-liu-dun .c3toc a[aria-current="true"] .ld-pi circle { stroke: var(--qing); opacity: 1; }
.c-liu-dun .c3toc a:hover span, .c-liu-dun .c3toc a:focus-visible span { max-width: 18em; }

/* 算筹 */
.ld-rd { display: inline-block; vertical-align: middle; overflow: visible; }
.ld-rd line { stroke: var(--ink); stroke-width: 1.45; stroke-linecap: round; }
.ld-rd .c { fill: none; stroke: var(--rule); stroke-width: .7; }
.ld-rd--y line { stroke: var(--dan); stroke-width: 1.8; }
.ld-rd--y .c { stroke: rgba(192, 57, 31, .28); }
.ld-rd--xs line { stroke-width: 1.3; }

/* 版：四周双边 */
.ld-ban { position: relative; display: grid; grid-template-columns: minmax(0, 1fr) 44px minmax(0, 1.06fr); max-width: 1320px; margin: 0 auto;
  background: var(--paper); border: 3px solid var(--ink); box-shadow: inset 0 0 0 4px var(--paper), inset 0 0 0 5px var(--ink), 0 1px 0 rgba(28, 26, 22, .08), 0 18px 40px -26px rgba(28, 26, 22, .35); }
.ld-tu { min-width: 0; padding: clamp(18px, 2.4vw, 34px); }
.ld-tu__in { position: sticky; top: calc(var(--bar) + 26px); display: flex; flex-direction: column; gap: 14px; }
.ld-ban--hero .ld-tu { display: flex; flex-direction: column; justify-content: center; }
.ld-ban--hero .ld-tu__in { position: static; }
.ld-ban--wide { grid-template-columns: minmax(0, 1.22fr) 44px minmax(0, 1fr); }
.ld-shi { min-width: 0; padding: clamp(20px, 2.6vw, 38px) clamp(20px, 2.8vw, 42px); }
/* 版心：书名、鱼尾、问次、觚数、页次 */
.ld-xin { display: flex; flex-direction: column; align-items: center; gap: 10px; padding: 18px 0; border-left: 1px solid var(--ink); border-right: 1px solid var(--ink); color: var(--ink-2); }
.ld-xin span { writing-mode: vertical-rl; text-orientation: upright; letter-spacing: .18em; line-height: 1; }
.ld-xin__t { font-size: 14px; font-weight: 700; color: var(--ink); }
.ld-xin__n { font-size: 13px; }
.ld-xin__g { display: flex; align-items: center; gap: 6px; font-size: 13px; }
.ld-xin__g em { font-style: normal; color: var(--dan); }
.ld-xin__g .ld-pi { color: var(--dan); }
.ld-xin__g .ld-pi circle { stroke: var(--qing); opacity: 1; }
.ld-xin__p { margin-top: auto; writing-mode: horizontal-tb !important; }
.ld-yw { display: block; width: 30px; height: 15px; background: var(--ink); clip-path: polygon(0 0, 100% 0, 100% 100%, 50% 42%, 0 100%); }
.ld-yw--up { transform: rotate(180deg); }

/* 首屏 */
.c-liu-dun .c3hero { padding: calc(var(--bar) + 18px) clamp(10px, 2.6vw, 40px) 44px; }
.ld-ban--hero { min-height: calc(100svh - var(--bar) - 64px); grid-template-columns: minmax(0, 1fr) 44px minmax(0, 1fr); }
.ld-ban--hero .ld-shi { position: relative; display: flex; flex-direction: column; justify-content: center; }
.ld-nm { display: flex; align-items: flex-start; gap: clamp(14px, 2vw, 28px); }
.ld-tiji { display: flex; flex-direction: column; gap: 4px; margin: 8px 0 0; writing-mode: vertical-rl; line-height: 1; }
.ld-tiji span { font-family: var(--brush); font-size: clamp(22px, 2.1vw, 28px); letter-spacing: .06em; color: var(--dan); }
.ld-tiji small { font-size: 11.5px; letter-spacing: .2em; color: var(--ink-3); padding-top: 4px; }
.ld-k { margin: 0; font-size: 13px; letter-spacing: .16em; color: var(--ink-3); }
.ld-ban--hero h1 { margin: 2px 0 0; font-family: var(--head); font-weight: 900; font-size: clamp(64px, 7.4vw, 110px); line-height: 1; letter-spacing: .08em; }
.ld-en { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 12px; margin: 8px 0 10px; color: var(--ink-2); }
.ld-en span[lang] { font-size: 20px; font-style: italic; letter-spacing: .04em; }
.ld-en__y { font-size: 14px; color: var(--ink-3); }
.ld-who { margin: 0 0 2px; font-size: 18.5px; font-weight: 700; line-height: 1.55; }
.ld-now { margin: 0 0 12px; font-size: 13.5px; color: var(--ink-3); line-height: 1.65; }
.ld-rel { margin: 0 0 12px; padding: 9px 14px 10px; background: rgba(43, 91, 143, .055); border-left: 3px solid var(--qing); }
.ld-rel .mk { margin-bottom: 2px; color: var(--qing); font-weight: 700; letter-spacing: .14em; }
.ld-rel p:last-child { margin: 0; font-size: 14.5px; line-height: 1.75; }
.ld-hb { margin: 0 0 12px; display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; }
.ld-hb .mk, .ld-hq .mk { margin: 0; color: var(--dan); font-weight: 700; letter-spacing: .14em; }
.ld-bk { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 4px 16px; }
.ld-bk li { display: flex; align-items: baseline; gap: 5px; font-size: 15px; }
.ld-bk a { text-decoration: none; font-weight: 700; }
.ld-bk a:hover { color: var(--dan); text-decoration: underline; }
.ld-bk small { font-size: 12px; color: var(--ink-3); }
.ld-hq { margin: 0 0 14px; }
.ld-hq .mk { margin-bottom: 4px; }
.ld-ql { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--rule); }
.ld-ql a { display: grid; grid-template-columns: 7.4em minmax(0, 1fr); align-items: center; gap: 10px; min-height: 40px; padding: 2px 0; border-bottom: 1px solid var(--rule); text-decoration: none; }
.ld-ql__y { display: flex; align-items: center; gap: 6px; }
.ld-ql__y b { font-size: 13px; font-weight: 400; color: var(--ink-3); font-variant-numeric: tabular-nums; }
.ld-ql__q { font-size: 15.5px; line-height: 1.45; }
.ld-ql__p { color: var(--ink-3); }
.ld-ql a:hover .ld-ql__q, .ld-ql a:focus-visible .ld-ql__q { color: var(--dan); }
.ld-ql a:hover .ld-ql__p { color: var(--dan); }
.ld-go { margin: 4px 0 0; }
.c-liu-dun .c3-btn { border-radius: 0; font-family: var(--body); min-height: 40px; }
.c-liu-dun .c3-btn--go { background: var(--dan); border-color: var(--dan); color: var(--acc-ink); }
.c-liu-dun .c3-btn--deep { background: transparent; color: var(--ink); border-color: var(--ink); }
.c-liu-dun .c3-btn--wm { border-color: var(--rule); color: var(--ink-2); }

/* 割圆 */
.ld-cut { margin: 0; display: grid; grid-template-columns: minmax(0, 1fr); gap: 10px; }
.ld-cut__k { display: flex; align-items: baseline; gap: 12px; margin: 0; }
.ld-cut__k b { font-family: var(--brush); font-weight: 400; font-size: 34px; line-height: 1; color: var(--dan); }
.ld-cut__k span { font-size: 14px; letter-spacing: .1em; color: var(--ink-3); }
.ld-cut__fig { position: relative; width: min(100%, 470px); margin: 0 auto; }
.ld-cut__svg { display: block; width: 100%; height: auto; overflow: visible; }
.ld-c { fill: none; stroke: var(--qing); stroke-width: 2.6; }
.ld-in { fill: none; stroke: var(--dan); stroke-width: 2.4; stroke-linejoin: round; }
.ld-loss { fill: var(--dan); fill-opacity: .2; fill-rule: evenodd; stroke: none; }
.ld-spk { fill: none; stroke: var(--ink); stroke-width: 1; stroke-opacity: .3; transition: stroke-opacity .5s; }
.ld-out { fill: none; stroke: var(--ink); stroke-width: 1.5; stroke-dasharray: 7 5; opacity: 0; transition: opacity .4s; }
.ld-cut.is-arch .ld-out { opacity: .85; }
.ld-new circle { fill: var(--dan); }
.ld-tag line { stroke: var(--dan); stroke-width: 3; stroke-linecap: round; }
.ld-tag line:first-child { stroke: var(--ink); stroke-width: 2; stroke-dasharray: 2 5; }
.ld-tag text { font-family: var(--body); font-size: 22px; fill: var(--ink); paint-order: stroke; stroke: var(--paper); stroke-width: 5px; }
.ld-tag .ld-tag__s { fill: var(--dan); }
.ld-tag { transition: opacity .4s; }
.ld-cut.is-cut .ld-tag { opacity: 0; }
.ld-cut__read { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); border-top: 1px solid var(--ink); border-bottom: 1px solid var(--rule); }
.ld-r { margin: 0; padding: 8px 10px 9px; display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.ld-r + .ld-r { border-left: 1px solid var(--rule); }
.ld-r span { font-size: 12px; letter-spacing: .12em; color: var(--ink-3); }
.ld-r b { font-size: 21px; font-weight: 700; line-height: 1.25; font-variant-numeric: tabular-nums; overflow-wrap: anywhere; }
.ld-r--n b { color: var(--dan); }
.ld-r small { font-size: 11.5px; line-height: 1.45; color: var(--ink-3); }
.ld-r i { display: block; min-height: 20px; }
.ld-r i svg { max-width: 100%; height: auto; }
.ld-r--pi b { font-size: 19px; }
.ld-cut__ctl { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.ld-cut__ctl button, .ld-bd button, .ld-tw__ctl button, .ld-nr__ctl button, .ld-dir__ctl button, .ld-lp__btn {
  min-height: 40px; padding: 6px 14px; border: 1px solid var(--ink); border-radius: 0; background: transparent; color: var(--ink); font: inherit; font-size: 14.5px; cursor: pointer; }
.ld-cut__ctl button:hover, .ld-bd button:hover, .ld-tw__ctl button:hover, .ld-nr__ctl button:hover, .ld-dir__ctl button:hover { background: rgba(28, 26, 22, .06); }
.ld-cut__go { background: var(--dan) !important; border-color: var(--dan) !important; color: var(--acc-ink) !important; font-weight: 700 !important; min-width: 7.5em; }
.ld-cut__go:disabled { background: var(--ink-3) !important; border-color: var(--ink-3) !important; cursor: default; }
.ld-cut__mode { display: inline-flex; margin-left: auto; }
.ld-cut__mode button + button { border-left: 0; }
.ld-cut__mode button[aria-pressed="true"], .ld-dir__ctl button[aria-pressed="true"], .ld-nr__ctl button[aria-pressed="true"] { background: var(--ink); color: var(--paper); }
.ld-cut__out { margin: 0; min-height: 4.8em; font-size: 14.5px; line-height: 1.75; color: var(--ink-2); }
.ld-cut__out q { quotes: "“" "”"; color: var(--ink); }

/* 生平、成就、著作 */
.ld-ban--band { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0; margin-top: 22px; padding: 6px; }
.ld-band__c { padding: 22px 26px 24px; min-width: 0; }
.ld-band__c + .ld-band__c { border-left: 1px solid var(--ink); }
.ld-band__c .mk { margin: 0 0 8px; color: var(--dan); font-weight: 700; letter-spacing: .16em; }
.ld-mk2 { margin-top: 18px !important; }
.ld-facts { margin: 0; font-size: 14.5px; line-height: 1.85; color: var(--ink-2); }
.c-liu-dun .c3-feats { margin: 0; padding: 0; list-style: none; counter-reset: f; }
.c-liu-dun .c3-feats li { counter-increment: f; position: relative; padding: 5px 0 6px 28px; font-size: 14.5px; line-height: 1.65; border-bottom: 1px solid var(--rule); }
.c-liu-dun .c3-feats li::before { content: counter(f, cjk-ideographic); position: absolute; left: 0; top: 4px; font-family: var(--brush); font-size: 17px; color: var(--dan); }
.c-liu-dun .c3-books li, .c-liu-dun .c3-links li { font-size: 14.5px; border-bottom: 1px solid var(--rule); }
.c-liu-dun .c3-books a, .c-liu-dun .c3-links a { text-decoration-color: var(--rule); text-underline-offset: .2em; }
.c-liu-dun .c3-books a:hover, .c-liu-dun .c3-links a:hover { color: var(--dan); }

/* 每一问：一块版 */
.c-liu-dun .c3q { display: block; padding: 16px clamp(10px, 2.6vw, 40px) 36px; }
.c-liu-dun .c3q .ld-ban { min-height: calc(100svh - var(--bar) - 64px); }
.ld-when { display: flex; flex-wrap: wrap; align-items: center; gap: 4px 12px; }
.c-liu-dun .ld-when b { font-size: 26px; color: var(--dan); font-weight: 700; }
.c-liu-dun .ld-when span { font-size: 14px; color: var(--ink-3); }
.c-liu-dun .c3q__q { margin: 8px 0 16px; font-size: clamp(30px, 3.4vw, 46px); letter-spacing: .03em; line-height: 1.22; }
.c-liu-dun .c3q__lede { font-size: 16.5px; line-height: 1.95; text-align: justify; }
.c-liu-dun .c3-quote { margin: 20px 0; padding: 14px 18px 12px 20px; border-left: 0; background: linear-gradient(90deg, rgba(43, 91, 143, .075), rgba(43, 91, 143, .015)); box-shadow: inset 3px 0 0 var(--qing); }
.c-liu-dun .c3-quote blockquote p { font-size: 17.5px; line-height: 1.75; color: var(--ink); }
.c-liu-dun .c3-quote blockquote p::before, .c-liu-dun .c3-quote blockquote p::after { color: var(--qing); }
.c-liu-dun .c3-quote figcaption { color: var(--ink-3); }
.c-liu-dun .c3-tags li { border-radius: 0; border-color: var(--rule); background: var(--paper); }
.c-liu-dun .c3-works .mk, .c-liu-dun .c3-talk .mk { color: var(--dan); letter-spacing: .14em; }
.c-liu-dun .c3-works li { position: relative; padding: 4px 0 4px 16px; }
.c-liu-dun .c3-works li::before { content: ""; position: absolute; left: 0; top: .95em; width: 6px; height: 6px; background: var(--dan); }
.c-liu-dun .talk { border-radius: 0; border-color: var(--ink); background: var(--paper); }
.c-liu-dun .talk:hover { box-shadow: 4px 4px 0 var(--dan-2); }
.c-liu-dun .c3-ask { border-radius: 0; border-color: var(--ink-3); }
.c-liu-dun .c3-deeplink { color: var(--dan); }

/* 图：影印页、铜版画 */
.ld-fig { margin: 0; }
.ld-fig img { display: block; width: 100%; height: auto; }
.ld-fig figcaption, .ld-cap { margin: 8px 0 0; font-size: 13px; line-height: 1.65; color: var(--ink-3); }
.ld-pair { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0; border: 1px solid var(--rule); box-shadow: 0 10px 26px -18px rgba(28, 26, 22, .5); }
.ld-pg { margin: 0; min-width: 0; }
.ld-pg img { display: block; width: 100%; height: auto; }
.ld-pair .ld-pg + .ld-pg { border-left: 1px solid var(--rule); }
.ld-pg__w { position: relative; }
.ld-quan { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; }
.ld-quan circle { fill: none; stroke: var(--dan); stroke-width: 3.6; stroke-dasharray: 90; stroke-dashoffset: 90; }
.c-liu-dun .is-in .ld-quan circle { transition: stroke-dashoffset .45s ease calc(var(--k) * 40ms + .3s); stroke-dashoffset: 0; }
.ld-shiwen { margin-top: 4px; font-size: 13.5px; line-height: 1.75; color: var(--ink-2); border-top: 1px solid var(--rule); padding-top: 6px; }
.ld-shiwen summary { cursor: pointer; min-height: 40px; display: flex; align-items: center; font-weight: 700; color: var(--dan); }
.ld-shiwen p { margin: 4px 0 8px; }
.ld-shiwen b { display: block; font-size: 12px; letter-spacing: .12em; color: var(--ink-3); }

/* 西学东渐 / 西学中源 */
.ld-dir { display: grid; grid-template-columns: auto minmax(0, 1fr); align-items: center; gap: 8px 16px; padding: 12px 14px; border: 1px solid var(--rule); background: rgba(242, 237, 226, .5); }
.ld-dir__ab { display: flex; align-items: center; gap: 6px; grid-row: span 2; }
.ld-dir__ab span { display: grid; place-items: center; width: 40px; height: 40px; border: 1.5px solid var(--ink); font-size: 20px; font-weight: 900; }
.ld-dir__ar { width: 74px; height: 24px; transition: transform .6s cubic-bezier(.6, 0, .3, 1); }
.ld-dir__ar line, .ld-dir__ar .h { fill: none; stroke: var(--dan); stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }
.ld-dir.is-yuan .ld-dir__ar { transform: scaleX(-1); }
.ld-dir__ctl { display: flex; flex-wrap: wrap; }
.ld-dir__ctl button + button { border-left: 0; }
.ld-dir__out { grid-column: 2; margin: 0; font-size: 14px; line-height: 1.7; color: var(--ink-2); min-height: 3.4em; }

/* 大哉言数 + 布算 */
.ld-sx { display: grid; grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr); gap: 20px; align-items: start; }
.ld-pg--c { border: 1px solid var(--rule); }
.ld-pg--c figcaption { padding: 8px 10px; font-size: 12.5px; line-height: 1.6; color: var(--ink-3); border-top: 1px solid var(--rule); }
.ld-bd { padding: 12px 14px 14px; border: 1px solid var(--ink); background: var(--paper); }
.ld-bd__k { margin: 0 0 6px; font-family: var(--brush); font-size: 28px; line-height: 1; color: var(--dan); }
.ld-bd__in { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 8px; }
.ld-bd__in label { font-size: 13px; color: var(--ink-3); }
.ld-bd__in input { width: 7.2em; min-height: 40px; padding: 4px 8px; border: 1px solid var(--ink); border-radius: 0; background: #fff; color: var(--ink); font: inherit; font-size: 18px; letter-spacing: .08em; font-variant-numeric: tabular-nums; }
.ld-bd__chips { display: inline-flex; flex-wrap: wrap; gap: 4px; }
.ld-bd__chips button { min-height: 40px; padding: 4px 10px; font-size: 13.5px; }
.ld-bd__board { margin: 12px 0 6px; overflow-x: auto; }
.ld-bd__board svg { display: block; max-width: 100%; height: auto; }
.ld-bd__board .cell { fill: rgba(214, 179, 106, .1); stroke: var(--bamboo-2); stroke-opacity: .5; stroke-width: 1; }
.ld-bd__board .rod { fill: var(--bamboo); stroke: var(--bamboo-2); stroke-width: 1; }
.ld-bd__board .pl { font-family: var(--body); font-size: 13px; fill: var(--ink-3); text-anchor: middle; }
.ld-bd__board .pz { font-family: var(--body); font-size: 11px; fill: var(--dan); text-anchor: middle; }
.ld-bd__out { margin: 0; font-size: 14px; line-height: 1.7; color: var(--ink-2); min-height: 1.7em; }
.ld-bd__n { margin: 8px 0 0; padding-top: 8px; border-top: 1px solid var(--rule); font-size: 13px; line-height: 1.7; color: var(--ink-3); }

/* 五轮塔与五种立体 */
.ld-gr { display: grid; grid-template-columns: minmax(0, .82fr) minmax(0, 1.18fr); gap: 18px; align-items: start; }
.ld-fig--kep img { border: 1px solid var(--rule); }
.ld-tw { padding: 12px 14px 14px; border: 1px solid var(--ink); background: var(--paper); }
.ld-tw__k { margin: 0 0 4px; font-family: var(--brush); font-size: 26px; line-height: 1.1; color: var(--dan); }
.ld-tw__svg { display: block; width: 100%; height: auto; max-height: 56vh; }
.ld-tw__svg .lv { fill: #fbf8f1; stroke: var(--ink); stroke-width: 2; transition: transform .6s cubic-bezier(.2, .9, .3, 1.2), opacity .4s; }
.ld-tw__svg .lv.is-on { fill: var(--dan-2); stroke: var(--dan); }
.ld-tw__svg .lv.is-off { opacity: 0; transform: translateY(-60px); }
.ld-tw__svg .gh { fill: none; stroke: var(--rule); stroke-width: 1.2; stroke-dasharray: 4 4; }
.ld-tw__svg .sd { fill: none; stroke: var(--qing); stroke-width: 1.5; stroke-linejoin: round; transition: opacity .5s; }
.ld-tw__svg .sd .bk { stroke-opacity: .28; }
.ld-tw__svg .sd.is-off { opacity: .22; stroke: var(--ink-3); }
.ld-tw__svg .lk { fill: none; stroke: var(--ink-3); stroke-width: 1.2; stroke-dasharray: 2 4; transition: opacity .5s; }
.ld-tw__svg .lk.is-off { opacity: 0; }
.ld-tw__svg text { font-family: var(--body); font-size: 15px; fill: var(--ink); }
.ld-tw__svg text.el { font-size: 13px; fill: var(--ink-3); }
.ld-tw__svg text.is-off { opacity: 0; }
.ld-tw__svg text { transition: opacity .5s; }
.ld-tw__ctl { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 6px; }
.ld-tw__go { background: var(--dan) !important; border-color: var(--dan) !important; color: var(--acc-ink) !important; font-weight: 700; }
.ld-tw__go:disabled { background: var(--ink-3) !important; border-color: var(--ink-3) !important; }
.ld-tw__out { margin: 8px 0 0; font-size: 14px; line-height: 1.7; color: var(--ink-2); min-height: 3.4em; }

/* 新发明：在画上找 */
.ld-nr__w { position: relative; }
.ld-nr__ov { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; }
.ld-nr__dim { fill: rgba(28, 26, 22, .62); opacity: 0; transition: opacity .45s; }
.ld-nr.is-on .ld-nr__dim { opacity: 1; }
.ld-nr__rings * { fill: none; stroke: var(--dan); stroke-width: 5; stroke-linejoin: round; }
.ld-nr__ctl { display: flex; flex-wrap: wrap; gap: 0; margin-top: 10px; }
.ld-nr__ctl button + button { border-left: 0; }
.ld-nr__out { margin: 8px 0 0; font-size: 14.5px; line-height: 1.75; color: var(--ink-2); min-height: 3.5em; }

/* 空气泵与放大镜；课程说明的小问号 */
.ld-ap { position: relative; overflow: hidden; touch-action: pan-y; }
.ld-ap img { display: block; width: 100%; height: auto; }
.ld-lp { position: absolute; left: 50%; top: 50%; width: 168px; height: 168px; margin: -84px 0 0 -84px; border-radius: 50%; border: 3px solid var(--dan);
  box-shadow: 0 0 0 4px rgba(251, 248, 241, .7), 0 10px 30px rgba(0, 0, 0, .5); background-repeat: no-repeat; filter: brightness(1.75) contrast(1.08); opacity: 0; transform: scale(.6); transition: opacity .25s, transform .25s; pointer-events: none; }
.ld-ap.is-lp .ld-lp { opacity: 1; transform: scale(1); }
.ld-ap.is-lp { cursor: none; }
.ld-lp__btn { margin-left: 8px; min-height: 40px !important; padding: 2px 10px !important; font-size: 13px !important; vertical-align: middle; }
.ld-lp__btn[aria-pressed="true"] { background: var(--dan) !important; border-color: var(--dan) !important; color: var(--acc-ink) !important; }
.ld-dq { margin-top: 4px; }
.ld-dq__k { margin: 0 0 8px; font-size: 13px; letter-spacing: .06em; color: var(--ink-3); }
.ld-dq ul { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.ld-dq button { position: relative; display: block; width: 100%; min-height: 64px; padding: 10px 12px 10px 46px; border: 1px solid var(--ink); background: var(--paper); color: var(--ink); font: inherit; text-align: left; cursor: pointer; transition: background .2s; }
.ld-dq button:hover { background: #fff; }
.ld-dq__q { position: absolute; left: 10px; top: 50%; transform: translateY(-50%); display: grid; place-items: center; width: 26px; height: 26px; border-radius: 50%; background: var(--dan); color: var(--acc-ink); font-weight: 900; font-size: 15px; transition: transform .4s; }
.ld-dq__h { display: block; font-weight: 700; font-size: 15px; }
.ld-dq__a { display: block; max-height: 0; overflow: hidden; font-size: 13.5px; line-height: 1.6; color: var(--ink-2); transition: max-height .35s ease, margin .35s; }
.ld-dq button[aria-expanded="true"] .ld-dq__a { max-height: 6em; margin-top: 4px; }
.ld-dq button[aria-expanded="true"] .ld-dq__q { transform: translateY(-50%) rotate(360deg); background: var(--qing); }

/* 结尾：与圆合体 */
.c-liu-dun .c3end { padding: 16px clamp(10px, 2.6vw, 40px) 56px; }
.ld-ban--end { grid-template-columns: minmax(0, .62fr) 44px minmax(0, 1.38fr); }
.ld-ban--end .ld-tu { justify-content: flex-start; padding-top: 48px; }
.ld-he { margin: 0; position: sticky; top: calc(var(--bar) + 30px); text-align: center; }
.ld-he svg { width: min(100%, 230px); height: auto; }
.ld-he__c { fill: none; stroke: var(--qing); stroke-width: 3; }
.ld-he__p { fill: var(--dan-2); stroke: var(--dan); stroke-width: 2; stroke-dasharray: 629; stroke-dashoffset: 629; transform: rotate(-90deg); transform-origin: 120px 120px; }
.c-liu-dun .c3end.is-in .ld-he__p { transition: stroke-dashoffset 2.4s cubic-bezier(.4, 0, .2, 1) .2s; stroke-dashoffset: 0; }
.ld-he figcaption { margin-top: 12px; font-size: 15px; line-height: 1.8; color: var(--ink); }
.ld-he figcaption small { display: block; font-size: 12.5px; color: var(--ink-3); }
.c-liu-dun .c3end h2 { margin: 0 0 18px; font-weight: 900; letter-spacing: .06em; }
.c-liu-dun .c3end h3 { color: var(--dan); letter-spacing: .1em; font-size: 16px; }
.c-liu-dun .c3-lin { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
.c-liu-dun .c3-lin li { border-radius: 0; border-color: var(--rule); background: #fff; }
.c-liu-dun .c3-lin .rel { border-radius: 0; }
.c-liu-dun .c3-endgo .c3-btn { border-radius: 0; }

/* 桌面：给右边的目录让出位置 */
@media (min-width: 861px) {
  .c-liu-dun .c3hero, .c-liu-dun .c3q, .c-liu-dun .c3end { padding-right: 84px; }
}
@media (max-width: 1180px) {
  .ld-ban--hero { grid-template-columns: minmax(0, .9fr) 40px minmax(0, 1fr); }
  .ld-ban { grid-template-columns: minmax(0, 1fr) 40px minmax(0, 1.08fr); }
  .ld-sx, .ld-gr { grid-template-columns: minmax(0, 1fr); }
  .ld-pg--c { max-width: 360px; }
  .ld-fig--kep { max-width: 320px; }
  .ld-cut__mode { margin-left: 0; }
  .ld-r b { font-size: 18px; }
  .ld-r--pi b { font-size: 16px; }
}
@media (max-width: 860px) {
  .ld-ban, .ld-ban--hero, .ld-ban--end { grid-template-columns: minmax(0, 1fr); grid-template-areas: "xin" "shi" "tu"; min-height: 0 !important; }
  .ld-xin { grid-area: xin; flex-direction: row; justify-content: flex-start; flex-wrap: wrap; gap: 6px 12px; padding: 8px 14px; border: 0; border-bottom: 1px solid var(--ink); }
  .ld-xin span { writing-mode: horizontal-tb; letter-spacing: .1em; }
  .ld-xin__p { margin: 0 0 0 auto; }
  .ld-yw { width: 22px; height: 11px; }
  .ld-shi { grid-area: shi; }
  .ld-tu { grid-area: tu; border-top: 1px solid var(--rule); }
  .ld-ban--hero .ld-shi { padding-top: 18px; }
  .ld-tiji span { font-size: 24px; }
  .ld-ban--band { grid-template-columns: minmax(0, 1fr); }
  .ld-band__c + .ld-band__c { border-left: 0; border-top: 1px solid var(--ink); }
  .ld-he { position: static; }
  .ld-ban--end .ld-tu { padding-top: 22px; }
  .c-liu-dun .c3q .ld-ban { min-height: 0; }
}
@media (max-width: 560px) {
  .c-liu-dun .c3hero, .c-liu-dun .c3q, .c-liu-dun .c3end { padding-left: 8px; padding-right: 8px; }
  .ld-ban { box-shadow: inset 0 0 0 3px var(--paper), inset 0 0 0 4px var(--ink); border-width: 2px; }
  .ld-shi { padding: 18px 16px 20px; }
  .ld-tu { padding: 16px 14px; }
  .ld-ban--hero h1 { font-size: 64px; }
  .ld-ql a { grid-template-columns: 6.6em minmax(0, 1fr) 18px; gap: 8px; }
  .ld-ql__q { font-size: 14.5px; }
  .ld-cut__read { grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr); }
  .ld-r--loss { grid-column: span 2; border-left: 0 !important; border-top: 1px solid var(--rule); }
  .ld-pair { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .ld-dq ul { grid-template-columns: minmax(0, 1fr); }
  .ld-dir { grid-template-columns: minmax(0, 1fr); }
  .ld-dir__ab { grid-row: auto; }
  .ld-dir__out { grid-column: 1; }
  .c-liu-dun .c3q__q { font-size: 29px; }
}