.book-layout,.book-mobile-bar{--bk-bg: #ffffff;--bk-bg-soft: #f3f8fb;--bk-panel: #ffffff;--bk-ink: #15324a;--bk-ink-soft: #5a7488;--bk-line: rgba(0, 60, 104, .12);--bk-brand: #003c68;--bk-accent: #1389ab;--bk-accent-soft: rgba(28, 164, 199, .12)}[data-theme=dark] .book-layout,[data-theme=dark].book-layout,[data-theme=dark] .book-mobile-bar,[data-theme=dark].book-mobile-bar{--bk-bg: #0e1822;--bk-bg-soft: #16242f;--bk-panel: #16242f;--bk-ink: #e6eef4;--bk-ink-soft: #9fb4c2;--bk-line: rgba(255, 255, 255, .12);--bk-brand: #e6eef4;--bk-accent: #5fc7e0;--bk-accent-soft: rgba(95, 199, 224, .14)}[data-theme=dark] body{background:#0e1822}[data-theme=dark] header.site{background:#0e1822eb;border-bottom-color:#ffffff1a}[data-theme=dark] header.site .wm{color:#e6eef4}[data-theme=dark] header.site .nav-top{color:#cfdee9}[data-theme=dark] footer.site{background:#0b131b;border-top-color:#ffffff1a;color:#9fb4c2}[data-theme=dark] footer.site .foot-col h2{color:#e6eef4}.book-layout{display:grid;grid-template-columns:280px minmax(0,1fr) 250px;max-width:1380px;margin:0 auto;background:var(--bk-bg);color:var(--bk-ink)}@media(max-width:1180px){.book-layout{grid-template-columns:260px minmax(0,1fr)}.book-layout__toc{display:none}}@media(max-width:900px){.book-layout{grid-template-columns:minmax(0,1fr)}}.book-layout__sidebar{border-right:1px solid var(--bk-line)}.book-sidebar{position:sticky;top:64px;max-height:calc(100vh - 64px);overflow-y:auto;padding:26px 18px 32px;display:flex;flex-direction:column;gap:4px}.book-sidebar__back{display:inline-flex;align-items:center;gap:7px;font-size:.82rem;font-weight:600;color:var(--bk-ink-soft);margin-bottom:14px}.book-sidebar__back:hover{color:var(--bk-accent)}.book-sidebar__back svg{width:13px;height:13px}.book-sidebar__book-title{margin:0 0 16px;font-size:1.02rem;font-weight:800;letter-spacing:-.01em;color:var(--bk-brand);line-height:1.25}.book-sidebar__group{margin-bottom:16px}.book-sidebar__group-head{display:block;font-size:.66rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--bk-accent);margin:0 0 7px}.book-sidebar__group-head span{color:var(--bk-ink-soft)}.book-sidebar__chapters{list-style:none;margin:0;padding:0}.book-sidebar__chapter-link{display:flex;gap:9px;padding:6px 9px;border-radius:8px;font-size:.86rem;line-height:1.35;color:var(--bk-ink);font-weight:500}.book-sidebar__chapter-link .n{flex:none;min-width:19px;height:19px;padding:0 3px;border-radius:6px;background:var(--bk-bg-soft);color:var(--bk-ink-soft);font-size:.66rem;font-weight:700;display:grid;place-items:center;margin-top:1px}.book-sidebar__chapter-link:hover{background:var(--bk-bg-soft);color:var(--bk-brand)}.book-sidebar__chapter-link.is-active{background:var(--bk-accent-soft);color:var(--bk-accent);font-weight:700}.book-sidebar__chapter-link.is-active .n{background:var(--bk-accent);color:#fff}.book-sidebar__chapter-link.is-visited .n:after{content:"✓"}.book-sidebar__chapter-link.is-visited.is-active .n:after{content:none}.book-sidebar__sections{list-style:none;margin:2px 0 4px;padding:0 0 0 28px}.book-sidebar__section-link{display:block;padding:4px 9px;border-left:2px solid var(--bk-line);font-size:.8rem;line-height:1.4;color:var(--bk-ink-soft)}.book-sidebar__section-link:hover{color:var(--bk-accent);border-left-color:var(--bk-accent)}.book-sidebar__section-link.is-active{color:var(--bk-accent);border-left-color:var(--bk-accent);font-weight:600}.book-sidebar__progress{margin:14px 0 0}.book-sidebar__progress span{font-size:.68rem;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--bk-ink-soft)}.book-sidebar__progress-outer{margin-top:6px;height:6px;border-radius:999px;background:var(--bk-bg-soft);overflow:hidden}.book-sidebar__progress-inner{height:100%;width:0;background:var(--bk-accent);border-radius:999px;transition:width .4s ease}.book-sidebar__promo{display:block;margin-top:18px;padding:13px 15px;border:1px solid var(--bk-line);border-radius:11px;background:var(--bk-accent-soft)}.book-sidebar__promo:hover{border-color:var(--bk-accent)}.book-sidebar__promo .eb{display:block;font-size:.64rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--bk-accent);margin-bottom:3px}.book-sidebar__promo .tt{display:block;font-size:.84rem;font-weight:700;color:var(--bk-brand);line-height:1.3}.book-sidebar__promo .bd{display:block;font-size:.76rem;color:var(--bk-ink-soft);line-height:1.45;margin-top:4px}.book-content{min-width:0;padding:34px clamp(20px,4vw,56px) 80px}.book-content__breadcrumb{font-size:.8rem;color:var(--bk-ink-soft);margin-bottom:14px}.book-content__breadcrumb a{color:var(--bk-ink-soft)}.book-content__breadcrumb a:hover{color:var(--bk-accent)}.book-content__breadcrumb span{margin:0 5px;opacity:.5}.book-content__label{font-size:.72rem;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--bk-accent);margin:0 0 6px}.book-content__title{margin:0;font-size:clamp(1.7rem,3.2vw,2.3rem);letter-spacing:-.03em;line-height:1.12;color:var(--bk-brand)}.book-content__meta{display:flex;flex-wrap:wrap;gap:16px;margin:12px 0 0;font-size:.82rem;color:var(--bk-ink-soft)}.book-content__meta span{display:inline-flex;align-items:center;gap:5px}.book-prose{margin-top:28px;font-size:1.02rem;line-height:1.75;color:var(--bk-ink)}.book-prose>h1:first-child{display:none}.book-prose>*:first-child{margin-top:0}.book-prose>h1:first-child+*{margin-top:0}.book-prose h2{margin:2em 0 .6em;padding-top:.4em;font-size:1.42rem;letter-spacing:-.02em;line-height:1.2;color:var(--bk-brand);scroll-margin-top:84px}.book-prose h3{margin:1.6em 0 .5em;font-size:1.12rem;letter-spacing:-.01em;color:var(--bk-brand);scroll-margin-top:84px}.book-prose p{margin:0 0 1.15em}.book-prose a{color:var(--bk-accent);font-weight:600}.book-prose strong{color:var(--bk-brand);font-weight:700}.book-prose ul,.book-prose ol{margin:0 0 1.2em;padding-left:1.4em}.book-prose li{margin:.3em 0}.book-prose code{background:var(--bk-bg-soft);padding:1px 6px;border-radius:5px;font-size:.9em;font-family:SFMono-Regular,ui-monospace,Menlo,monospace}.book-prose hr{border:none;border-top:1px solid var(--bk-line);margin:2.4em 0}.book-prose blockquote{margin:1.6em 0;padding:16px 20px;border:1px solid var(--bk-line);border-left:4px solid var(--bk-accent);border-radius:0 14px 14px 0;background:var(--bk-accent-soft)}.book-prose blockquote p{margin:.4em 0;color:var(--bk-ink)}.book-prose blockquote p:first-child{margin-top:0}.book-prose blockquote p:last-child{margin-bottom:0}.table-wrap{overflow-x:auto;margin:1.5em 0;border:1px solid var(--bk-line);border-radius:12px}.book-prose table{width:100%;border-collapse:collapse;font-size:.9rem}.book-prose th,.book-prose td{border:1px solid var(--bk-line);padding:9px 12px;text-align:left;vertical-align:top}.book-prose th{background:var(--bk-bg-soft);color:var(--bk-brand);font-weight:700}.chapter-nav{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:48px;padding-top:26px;border-top:1px solid var(--bk-line)}@media(max-width:560px){.chapter-nav{grid-template-columns:1fr}}.chapter-nav__link{display:flex;flex-direction:column;gap:4px;border:1px solid var(--bk-line);border-radius:14px;padding:14px 16px;transition:border-color .15s,box-shadow .15s}.chapter-nav__link:hover{border-color:var(--bk-accent);box-shadow:0 10px 26px -16px #00274266}.chapter-nav__link--next{text-align:right}.chapter-nav__dir{font-size:.72rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--bk-accent)}.chapter-nav__title{font-size:.9rem;font-weight:600;color:var(--bk-brand);line-height:1.35}.book-layout__toc{border-left:1px solid var(--bk-line)}.page-toc{position:sticky;top:64px;max-height:calc(100vh - 64px);overflow-y:auto;padding:26px 18px;display:flex;flex-direction:column;gap:22px}.page-toc__controls{display:flex;flex-direction:column;gap:2px}.page-toc__control{display:flex;align-items:center;gap:9px;width:100%;padding:7px 9px;border:none;background:none;border-radius:8px;font:inherit;font-size:.82rem;font-weight:500;color:var(--bk-ink-soft);cursor:pointer;text-align:left}.page-toc__control:hover{background:var(--bk-bg-soft);color:var(--bk-brand)}.page-toc__control svg{flex:none}.page-toc__title{margin:0 0 10px;font-size:.7rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--bk-ink-soft)}.page-toc__list{list-style:none;margin:0;padding:0;border-left:1px solid var(--bk-line)}.page-toc__item--sub{padding-left:14px}.page-toc__link{display:block;margin-left:-1px;padding:4px 0 4px 13px;border-left:2px solid transparent;font-size:.81rem;line-height:1.4;color:var(--bk-ink-soft)}.page-toc__link:hover{color:var(--bk-accent)}.page-toc__link.is-active{color:var(--bk-accent);border-left-color:var(--bk-accent);font-weight:600}.page-toc__cta{border-top:1px solid var(--bk-line);padding-top:18px}.page-toc__cta-label{margin:0 0 8px;font-size:.72rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--bk-ink-soft)}.page-toc__cta-link{display:block;font-size:.85rem;font-weight:600;color:var(--bk-accent);padding:3px 0}.book-mobile-bar{display:none}@media(max-width:900px){.book-mobile-bar{position:sticky;top:0;z-index:25;display:flex;align-items:center;gap:10px;padding:9px 14px;background:var(--bk-bg);border-bottom:1px solid var(--bk-line);color:var(--bk-ink)}.book-mobile-bar__menu,.book-mobile-bar__btn{flex:none;width:36px;height:36px;display:grid;place-items:center;border:1px solid var(--bk-line);border-radius:9px;background:var(--bk-panel);color:var(--bk-ink);cursor:pointer}.book-mobile-bar__title{flex:1;min-width:0;font-size:.86rem;font-weight:700;color:var(--bk-brand);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.book-mobile-bar__spacer{flex:1}}@media(max-width:900px){.book-layout__sidebar{position:fixed;top:0;left:0;bottom:0;width:300px;max-width:84vw;z-index:40;background:var(--bk-bg);transform:translate(-100%);transition:transform .22s ease;overflow-y:auto}.book-layout__sidebar.is-open{transform:none}.book-sidebar{position:static;max-height:none;top:0}}.book-sidebar__backdrop{display:none}.book-sidebar__backdrop.is-open{display:block;position:fixed;inset:0;z-index:35;background:#08141e80}html[data-reader-mode=on] .book-layout{grid-template-columns:minmax(0,1fr);max-width:820px}html[data-reader-mode=on] .book-layout__sidebar,html[data-reader-mode=on] .book-layout__toc{display:none}@media(max-width:900px){html[data-reader-mode=on] .book-layout__sidebar{display:block}}.book-reader-exit{display:none;position:fixed;bottom:22px;right:22px;z-index:30;align-items:center;gap:7px;padding:9px 15px;border:1px solid var(--line);border-radius:999px;background:#fff;box-shadow:0 10px 30px -10px #00274266;font-size:.82rem;font-weight:600;color:var(--brand);cursor:pointer}html[data-reader-mode=on] .book-reader-exit{display:inline-flex}.theme-icon{display:inline-grid;place-items:center;width:16px;height:16px}.theme-icon svg{grid-area:1 / 1;transition:transform .5s cubic-bezier(.34,1.56,.64,1),opacity .25s ease}.book-theme-toggle:hover .icon-sun{transform:rotate(40deg)}[data-theme=dark] .book-theme-toggle:hover .icon-moon{transform:rotate(-20deg)}.theme-icon .icon-moon{opacity:0;transform:rotate(90deg) scale(.4)}[data-theme=dark] .theme-icon .icon-sun{opacity:0;transform:rotate(-90deg) scale(.4)}[data-theme=dark] .theme-icon .icon-moon{opacity:1;transform:none}.book-mobile-bar__menu svg,.book-mobile-bar__btn svg,.book-sidebar__back svg,.page-toc__control svg,.book-reader-exit svg{transition:transform .18s ease}.book-mobile-bar__btn[aria-label^=Previous]:hover svg{transform:translate(-2px)}.book-mobile-bar__btn[aria-label^=Next]:hover svg{transform:translate(2px)}.book-mobile-bar__menu:hover svg{transform:scaleX(1.15)}.book-sidebar__back:hover svg{transform:translate(-3px)}.page-toc__control[data-reader-toggle]:hover svg{transform:scale(1.12)}.book-reader-exit svg{transition:transform .3s ease}.book-reader-exit:hover svg{transform:rotate(90deg)}.book-content__meta svg{animation:bk-meta-pop .45s cubic-bezier(.3,1.4,.4,1) both}.book-content__meta span:nth-child(2) svg{animation-delay:.12s}@keyframes bk-meta-pop{0%{opacity:0;transform:scale(.5)}to{opacity:1;transform:none}}.icon-clock path{transform-origin:8px 8px;animation:bk-clock-wind 1s cubic-bezier(.4,0,.2,1) .35s both}@keyframes bk-clock-wind{0%{transform:rotate(-360deg)}to{transform:rotate(0)}}@media(prefers-reduced-motion:reduce){.book-layout__sidebar,.book-sidebar__progress-inner{transition:none}.theme-icon svg,.book-mobile-bar__menu svg,.book-mobile-bar__btn svg,.book-sidebar__back svg,.page-toc__control svg,.book-reader-exit svg{transition:opacity .25s ease}.book-content__meta svg,.icon-clock path{animation:none}}.book-prose img{border-radius:var(--radius-md, 8px);margin:1.5rem 0;max-width:100%;max-height:min(55vh,480px);width:auto;height:auto;object-fit:contain}.book-prose figure{margin:1.75rem 0;padding:0}.book-prose figure img{display:block;margin:0 auto .6rem;max-width:100%;max-height:min(55vh,480px);width:auto;height:auto;object-fit:contain}.book-prose figcaption{font-size:.82rem;color:var(--ink-soft, #5b7186);line-height:1.5;text-align:center;padding:0 .5rem}@media(max-width:1024px){.book-prose img,.book-prose figure img{max-height:min(50vh,420px)}}@media(max-width:640px){.book-prose img,.book-prose figure img{max-height:45vh}}.callout{border-radius:var(--radius-lg, 14px);padding:1.25rem 1.5rem;margin:1.75rem 0;font-size:.95rem;line-height:1.6}.callout__label{display:flex;align-items:center;gap:.4rem;font-weight:700;font-size:.8rem;text-transform:uppercase;letter-spacing:.04em;margin-bottom:.5rem}.callout__label svg{width:16px;height:16px;flex-shrink:0}.callout>:last-child{margin-bottom:0}.callout__body>:last-child{margin-bottom:0}.callout--analogy{background:var(--callout-analogy-bg);border:1px solid var(--callout-analogy-border)}.callout--analogy .callout__label{color:var(--callout-analogy-label)}.callout--mnemonic{background:var(--callout-mnemonic-bg);border:1px solid var(--callout-mnemonic-border)}.callout--mnemonic .callout__label{color:var(--callout-mnemonic-label)}.callout--insight{background:var(--callout-insight-bg);border:1px solid var(--callout-insight-border)}.callout--insight .callout__label{color:var(--callout-insight-label)}.callout--passage-peek{background:var(--callout-passage-peek-bg);border:1px solid var(--callout-passage-peek-border)}.callout--passage-peek .callout__label{color:var(--callout-passage-peek-label)}.callout--tip{background:var(--callout-tip-bg);border:1px solid var(--callout-tip-border)}.callout--tip .callout__label{color:var(--callout-tip-label)}:root[data-theme=dark]{--callout-analogy-bg: #0e2a33;--callout-analogy-border: #1f6e84;--callout-analogy-label: #7ed5ec;--callout-mnemonic-bg: #1e1432;--callout-mnemonic-border: #6b3fa0;--callout-mnemonic-label: #c9a6ff;--callout-insight-bg: #2a1f0a;--callout-insight-border: #9a6c10;--callout-insight-label: #f5d89a;--callout-passage-peek-bg: #131a30;--callout-passage-peek-border: #3b5998;--callout-passage-peek-label: #b3c6f4;--callout-tip-bg: #0d2119;--callout-tip-border: #166534;--callout-tip-label: #86efac}