@charset "UTF-8";
:root{--paper:#f6f8f9;--white:#fff;--ink:#172d3d;--muted:#647580;--line:#dce4e8;--teal:#086b68;--teal-soft:#e3f0ed;--blue:#194a73;--sidebar:270px;--toc:225px;--content:850px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:88px}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;font-size:16px;line-height:1.8;-webkit-font-smoothing:antialiased}a{color:var(--teal);text-decoration-thickness:1px;text-underline-offset:4px}button,input{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid #137fa0;outline-offset:4px}::selection{background:#b9dbd4;color:#102f35}
.site-header{height:72px;display:flex;align-items:center;gap:36px;padding:0 max(28px,calc((100vw - 1440px)/2));background:rgba(255,255,255,.95);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}.brand{display:flex;gap:11px;align-items:center;color:var(--ink);text-decoration:none;white-space:nowrap;font-size:15px}.brand strong{font-weight:650}.brand-mark{background:var(--teal);color:white;display:grid;place-items:center;width:32px;height:32px;font-family:Georgia,serif;font-size:23px;border-radius:5px 13px 5px 5px}.header-nav{display:flex;gap:25px}.header-nav a{color:var(--muted);font-size:14px;text-decoration:none}.header-nav a:hover{color:var(--teal)}.search-trigger{margin-left:auto;border:1px solid var(--line);background:var(--paper);border-radius:6px;height:37px;display:flex;align-items:center;gap:9px;padding:0 10px;color:var(--muted);font-size:13px}.search-trigger svg,.search-box svg{height:18px;width:18px;fill:none;stroke:currentColor;stroke-width:1.7}.search-trigger kbd{font:12px inherit;border:1px solid var(--line);border-radius:3px;padding:0 5px;background:white;margin-left:25px}.site-footer{display:flex;justify-content:space-between;max-width:1220px;margin:80px auto 0;padding:30px;color:var(--muted);font-size:12px;border-top:1px solid var(--line)}
.home{max-width:1220px;margin:auto;padding:80px 32px 20px}.home-intro{max-width:710px;padding:15px 0 80px}.section-kicker{font-size:14px;color:var(--teal);margin:0 0 22px;font-weight:600}.home h1{font-size:clamp(40px,5.5vw,68px);font-weight:650;letter-spacing:-.055em;line-height:1.25;margin:0 0 26px}.home-intro>p:not(.section-kicker){font-size:17px;max-width:550px;color:var(--muted);line-height:1.9}.primary-search{margin:22px 0 0;background:var(--teal);border:1px solid var(--teal);border-radius:6px;padding:12px 18px;color:white;display:flex;gap:34px;align-items:center;font-size:14px}.primary-search:hover{background:#075b59}.primary-search span{font-size:12px;border:1px solid #6ca4a1;padding:0 5px;border-radius:3px}.section-heading{display:flex;align-items:baseline;justify-content:space-between;border-bottom:2px solid var(--ink);padding-bottom:18px;margin-bottom:0}.section-heading h2{font-size:23px;margin:0;letter-spacing:-.02em}.section-heading>span{font-size:13px;color:var(--muted)}.course-row{display:flex;align-items:center;gap:28px;padding:27px 6px;border-bottom:1px solid var(--line);color:var(--ink);text-decoration:none}.course-row:hover{background:#edf3f3}.course-number{font-family:Georgia,"Times New Roman",serif;font-size:30px;color:var(--teal);width:58px;flex-shrink:0}.course-info{display:flex;flex-direction:column;gap:4px}.course-info strong{font-size:17px;font-weight:600;line-height:1.6}.course-info>span{font-size:13px;color:var(--muted)}.row-arrow{margin-left:auto;font-size:22px;color:var(--teal)}.vocabulary-catalog{margin-top:70px}.vocabulary-grid{display:grid;grid-template-columns:1fr 1fr;gap:0 32px}.vocabulary-row{display:flex;flex-direction:column;padding:24px 6px;border-bottom:1px solid var(--line);color:var(--ink);text-decoration:none;gap:5px}.vocabulary-row strong{font-size:15px}.vocabulary-row span{font-size:13px;color:var(--muted)}.vocabulary-row:hover strong{color:var(--teal)}
.reading-layout{display:grid;grid-template-columns:var(--sidebar) minmax(0,var(--content)) var(--toc);gap:42px;max-width:1440px;margin:auto;padding:0 28px}.document-sidebar{position:sticky;top:72px;height:calc(100vh - 72px);overflow-y:auto;padding:34px 0 60px;border-right:1px solid var(--line);scrollbar-width:thin}.sidebar-home{font-size:13px;display:block;margin-bottom:27px}.sidebar-course{font-size:13px;font-weight:600;line-height:1.6;color:var(--ink);margin:0 24px 16px 0}.side-link{display:block;color:var(--muted);text-decoration:none;font-size:13px;line-height:1.5;padding:8px 18px 8px 0;margin-right:20px;border-bottom:1px solid #e8edef}.side-link:hover{color:var(--teal)}.side-section{font-size:12px;color:var(--muted);margin:28px 0 10px}.document-main{min-width:0;padding:32px 0 20px}.breadcrumbs{display:flex;flex-wrap:wrap;gap:9px;font-size:12px;color:var(--muted);margin-bottom:38px;line-height:1.6}.breadcrumbs a{color:var(--muted)}.toc-sidebar{position:sticky;top:72px;height:calc(100vh - 72px);overflow-y:auto;padding:34px 0;font-size:12px;line-height:1.6;scrollbar-width:thin}.toc-sidebar>div{font-weight:600;font-size:13px;margin-bottom:13px}.toc-sidebar ul{list-style:none;padding:0;margin:0}.toc-sidebar ul ul{padding-left:12px}.toc-sidebar li{margin:5px 0}.toc-sidebar a{display:block;color:var(--muted);text-decoration:none;padding:4px 0}.toc-sidebar a:hover,.toc-sidebar a.active{color:var(--teal)}.sidebar-toggle,.mobile-toc{display:none}
.article{font-size:16px;line-height:1.95;overflow-wrap:break-word}.article h1{font-size:clamp(27px,3vw,38px);line-height:1.5;letter-spacing:-.025em;margin:0 0 30px;font-weight:650}.article h2{font-size:24px;line-height:1.55;margin:58px 0 22px;padding-top:20px;border-top:1px solid var(--line);letter-spacing:-.015em}.article h3{font-size:20px;line-height:1.6;margin:42px 0 18px}.article h4{font-size:17px;margin:32px 0 14px}.article h5,.article h6{font-size:16px;margin:25px 0 12px}.article p{margin:16px 0}.article blockquote{margin:24px 0;padding:12px 22px;border-left:3px solid #81aaa5;background:#edf3f3;color:#49616a}.article blockquote p{margin:4px 0}.article hr{border:0;border-top:1px solid var(--line);margin:44px 0}.article li{margin:7px 0;padding-left:4px}.article li::marker{color:var(--teal)}.article strong{font-weight:650;color:#102c3b}.article code{font-family:"SFMono-Regular",Consolas,"Liberation Mono",monospace;font-size:.85em;background:#e9eff1;padding:2px 5px;border-radius:4px;color:#164e65}.article pre{background:#142b3b;color:#e5eff3;padding:22px;overflow:auto;border-radius:7px;line-height:1.75;margin:25px 0;max-width:100%}.article pre code{padding:0;background:transparent;color:inherit;font-size:13px;border-radius:0}.article table{display:block;overflow-x:auto;max-width:100%;border-collapse:collapse;margin:25px 0;font-size:14px;line-height:1.75}.article th,.article td{padding:11px 14px;border:1px solid var(--line);text-align:left;vertical-align:top;min-width:75px}.article th{background:#eaf0f2;font-weight:600;white-space:nowrap}.article tr:nth-child(even) td{background:#f0f4f5}.article td code{white-space:nowrap}.article input[type=checkbox]{accent-color:var(--teal);margin-right:5px}.article img{max-width:100%}.unpublished{color:var(--muted);text-decoration:underline dotted;cursor:help}.codehilite .k,.codehilite .kn{color:#9ac7f2}.codehilite .s,.codehilite .s1,.codehilite .s2{color:#b5d9a9}.codehilite .c,.codehilite .c1{color:#88a0ae}.codehilite .mi,.codehilite .mf{color:#e8c795}.codehilite .nf,.codehilite .nb{color:#9cd4ca}.page-navigation{display:grid;grid-template-columns:1fr 1fr;gap:20px;border-top:1px solid var(--line);padding-top:28px;margin-top:60px;font-size:14px;line-height:1.6}.page-navigation a{text-decoration:none}.page-navigation span{display:block;color:var(--muted);font-size:12px;margin-bottom:7px}.page-navigation .next{text-align:right}.page-navigation .next span{color:var(--muted)}
.search-dialog{border:0;border-radius:12px;padding:0;max-width:720px;width:calc(100% - 32px);position:fixed;top:10vh;margin:auto;background:var(--white);color:var(--ink);box-shadow:0 24px 100px #102b3940;max-height:80vh}.search-dialog::backdrop{background:#102b396b;backdrop-filter:blur(3px)}.search-box{display:flex;align-items:center;gap:13px;padding:20px;border-bottom:1px solid var(--line)}.search-box input{border:0;outline:0;flex:1;min-width:0;color:var(--ink);font-size:17px}.search-close{border:1px solid var(--line);background:white;border-radius:4px;font-size:12px;padding:4px 8px;color:var(--muted)}.search-hint{font-size:12px;color:var(--muted);padding:0 22px;margin:14px 0}.search-hint kbd{font:11px inherit;padding:1px 5px;border:1px solid var(--line);border-radius:3px}#search-results{overflow:auto;max-height:55vh;padding:0 12px 12px}.search-result{display:block;padding:16px 12px;border-top:1px solid var(--line);text-decoration:none;color:var(--ink)}.search-result:hover,.search-result:focus{background:var(--teal-soft)}.search-result strong{display:block;font-size:15px;font-weight:600}.search-result span{display:block;font-size:12px;color:var(--muted);margin:3px 0}.search-result p{font-size:13px;color:var(--muted);margin:5px 0 0;line-height:1.65}.search-result mark{color:var(--teal);background:#d9ebe5;padding:0 2px}.search-empty{padding:35px 12px;color:var(--muted);font-size:14px}.not-found{max-width:650px;padding:120px 28px;margin:auto}.not-found h1{font-size:34px}.not-found p{color:var(--muted)}
@media(min-width:1500px){:root{--sidebar:290px;--toc:250px;--content:880px}.reading-layout{gap:55px}}
@media(max-width:1150px){.reading-layout{grid-template-columns:240px minmax(0,1fr);gap:35px;max-width:1100px}.toc-sidebar{display:none}.mobile-toc{display:block;margin-bottom:25px;font-size:13px;border:1px solid var(--line);padding:10px 15px;border-radius:5px;background:white}.mobile-toc summary{cursor:pointer;color:var(--teal)}.mobile-toc ul{padding-left:20px}.mobile-toc a{color:var(--muted)}}
@media(max-width:760px){html{scroll-padding-top:76px}.site-header{height:62px;padding:0 18px;gap:20px}.brand{font-size:14px}.brand-mark{width:28px;height:28px;font-size:20px}.header-nav{display:none}.site-header .search-trigger{border:0;padding:5px;background:transparent}.site-header .search-trigger span,.site-header .search-trigger kbd{display:none}.home{padding:43px 22px 0}.home-intro{padding:0 0 55px}.home h1{font-size:42px}.home-intro>p:not(.section-kicker){font-size:15px}.section-kicker{font-size:13px}.course-row{gap:17px;padding:23px 0}.course-number{font-size:26px;width:44px}.course-info strong{font-size:15px}.row-arrow{font-size:18px}.vocabulary-grid{grid-template-columns:1fr}.vocabulary-catalog{margin-top:55px}.section-heading h2{font-size:21px}.site-footer{margin-top:55px;padding:24px 22px;flex-direction:column;gap:7px;font-size:11px}.reading-layout{display:block;padding:0 20px}.document-sidebar{display:none;position:fixed;z-index:30;top:62px;left:0;width:min(330px,90vw);height:calc(100vh - 62px);padding:25px;background:white;border-right:1px solid var(--line);box-shadow:10px 0 30px #1531401c}.sidebar-open .document-sidebar{display:block}.sidebar-toggle{display:block;position:sticky;top:62px;z-index:15;width:calc(100% + 40px);margin:0 -20px 22px;padding:10px 20px;text-align:left;border:0;border-bottom:1px solid var(--line);background:#f6f8f9ed;color:var(--teal);font-size:13px}.document-main{padding-top:0}.breadcrumbs{margin-bottom:25px;font-size:11px}.article{font-size:15px;line-height:1.95}.article h1{font-size:27px}.article h2{font-size:22px;margin-top:45px}.article h3{font-size:18px}.article pre{padding:16px;font-size:12px;margin-left:0;margin-right:0}.article table{font-size:13px}.article th,.article td{padding:9px 11px}.article blockquote{padding:10px 16px}.page-navigation{font-size:12px;gap:12px}.search-dialog{top:5vh;max-height:88vh}.search-box{padding:16px;gap:9px}.search-box input{font-size:15px}#search-results{max-height:64vh}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}