:root{--blue:#3569ed;--blue-soft:#edf3ff;--ink:#202b40;--muted:#8791a3;--border:#e8ecf3;--header:78px;--directory:302px;color-scheme:light;font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;color:var(--ink);background:#fff;font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,input,select{font:inherit}a{color:inherit;text-decoration:none}button,summary,select{cursor:pointer}button{border:0}button:disabled{cursor:default}button[hidden],[hidden]{display:none!important}::selection{background:#dce7ff}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible,[tabindex="0"]:focus-visible{outline:3px solid #99b7ff;outline-offset:3px;border-radius:5px}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip-link{position:fixed;top:-60px;left:16px;z-index:100;padding:12px;background:var(--blue);color:white}.skip-link:focus{top:12px}.site-header{height:var(--header);display:flex;align-items:center;gap:28px;border-bottom:1px solid var(--border);padding:0 28px 0 24px;background:white;position:relative;z-index:10}.brand{display:flex;align-items:center;gap:12px;flex:0 0 205px;white-space:nowrap}.brand-mark{display:grid;place-items:center;width:39px;height:42px;border-radius:11px;background:var(--blue);color:white;box-shadow:0 4px 12px #3569ed26}.brand-mark svg{width:27px;height:27px}.brand strong{display:block;font-size:17px;letter-spacing:.5px}.brand small{display:block;font-size:9px;letter-spacing:1.8px;color:#9aa3b1;margin-top:5px}.search-form{height:42px;display:flex;align-items:center;flex:1;max-width:680px;min-width:0;background:#f5f7fb;border:1px solid #edf0f5;border-radius:9px;gap:10px;padding:0 5px 0 13px}.search-icon{width:18px;height:18px;color:#929cac;flex-shrink:0}.search-form input{border:0;outline:0;background:transparent;min-width:0;flex:1;font-size:13px;color:var(--ink);width:100%}.search-form input::placeholder{color:#969fae}.search-form select{border:0;border-left:1px solid #dfe5ee;background:transparent;color:#7a879a;font-size:12px;max-width:135px;padding-left:9px;outline:0}.search-submit{font-size:12px;border-radius:6px;padding:7px 12px;background:white;color:#536884;box-shadow:0 1px 3px #18233b0b}.search-submit:hover{color:var(--blue)}.header-stat{display:flex;align-items:center;gap:8px;font-size:11px;color:#939caf;margin-left:auto;white-space:nowrap}.header-stat strong{font-size:12px;color:#52617a}.header-divider{height:13px;width:1px;background:var(--border);margin:0 4px}.status-dot{display:inline-block;width:6px;height:6px;border-radius:50%;background:#75a58c;vertical-align:middle;margin-right:5px}.workspace{display:grid;grid-template-columns:var(--directory) minmax(0,1fr);height:calc(100vh - var(--header));height:calc(100dvh - var(--header))}.question-pane,.reading-pane{overflow:auto;min-height:0;min-width:0;scrollbar-width:thin;scrollbar-color:#dce2ec transparent}.question-pane{background:#fff;border-right:1px solid var(--border);overflow:hidden}
.question-directory{display:flex;flex-direction:column;height:100%;min-height:0}
.directory-heading{padding:28px 20px 18px;border-bottom:1px solid var(--border);flex-shrink:0}
.eyebrow{color:#9ba7bc;font-size:9px;letter-spacing:1.6px;font-weight:600;margin:0 0 9px}
.directory-heading h2{margin:0;font-size:19px;font-weight:650;line-height:1.5}
.directory-count{display:block;font-size:11px;line-height:1.8;color:#8d98a9;margin:8px 0 0}
.directory-count>span{color:#a7b0bd}
.category-switcher{position:relative;flex-shrink:0}
.category-switcher>summary{list-style:none;display:flex;align-items:center;gap:9px;min-height:40px;padding:8px 12px;border:1px solid #e4eaf4;border-radius:8px;background:#fff;color:#536783;transition:background .18s,border-color .18s,box-shadow .18s}
.category-switcher>summary::-webkit-details-marker{display:none}
.category-switcher>summary:hover,.category-switcher[open]>summary{background:#f3f7ff;border-color:#cedcfa;color:#3569ed}
.category-switcher>summary:focus-visible{outline:2px solid #8baeff;outline-offset:3px}
.category-toggle-label{font-size:11px;color:#8a97ad;padding-right:9px;border-right:1px solid #e0e6f0}
.category-toggle-title{font-size:13px;font-weight:550;max-width:130px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.category-caret{width:17px;height:17px;flex-shrink:0;color:#8092b0;transform:rotate(0deg);transition:transform 220ms cubic-bezier(.2,.7,.2,1),color 180ms}
.category-switcher[open] .category-caret{transform:rotate(180deg);color:var(--blue)}
.category-popover{position:absolute;top:calc(100% + 12px);left:0;width:360px;max-width:calc(100vw - 32px);padding:18px;background:#fff;border:1px solid #e2e9f5;border-radius:13px;box-shadow:0 18px 55px #263c6026,0 3px 12px #263c600a;z-index:40;transform-origin:top left;animation:category-panel-in 180ms ease-out}
.category-popover-heading{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:0 2px 13px;font-size:12px;color:#526782}
.category-popover-heading strong{font-weight:600}.category-popover-heading>span{font-size:10px;color:#99a6ba}
.categories{padding:3px;margin:-3px;max-height:calc(100vh - var(--header) - 100px);max-height:min(520px,calc(100dvh - var(--header) - 100px));overflow:auto;scrollbar-width:thin}
@keyframes category-panel-in{from{opacity:0;transform:translateY(-6px) scale(.98)}to{opacity:1;transform:translateY(0) scale(1)}}
.category-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:5px}
.category-link{display:flex;align-items:center;gap:5px;padding:9px 8px;font-size:11px;border:1px solid #edf0f6;border-radius:6px;line-height:1.65;color:#647187;min-width:0;transition:background .12s}
.category-link:hover{background:#f2f6ff;border-color:#dce6fa}
.category-link.is-active{background:#e8efff;border-color:#d8e4ff;color:#3567db;font-weight:600}
.category-name{min-width:0;overflow-wrap:anywhere}
.category-icon{width:20px;text-align:center;color:#8694ad}
.nav-count{margin-left:auto;font-size:10px;font-weight:400;color:#9aa5b7;font-variant-numeric:tabular-nums;flex-shrink:0}
.is-active .nav-count{color:var(--blue)}
.all-link{margin-bottom:7px;gap:8px}
.directory-entries{overflow:auto;min-height:0;flex:1;padding-top:14px;scrollbar-width:thin;scrollbar-color:#dce2ec transparent}
.question-group{padding:0 12px 10px}.question-group>summary{display:flex;gap:5px;align-items:center;padding:11px 8px;font-size:10px;color:#8c97a9;list-style:none;line-height:1.6}.question-group>summary::-webkit-details-marker{display:none}.question-group>summary>span:nth-child(2){overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.group-caret{font-size:11px;transition:transform .1s}.question-group:not([open]) .group-caret{transform:rotate(-90deg)}.group-count{margin-left:auto;font-size:10px;flex-shrink:0}.question-link{display:flex;gap:10px;align-items:flex-start;padding:11px 12px 11px 9px;margin:3px 0;font-size:11px;line-height:1.85;color:#68758b;border-radius:7px;border:1px solid transparent}.question-link:hover{background:#f6f8fc;color:#34577b}.question-link.is-current{color:#3564c9;background:#eef4ff;border-color:#e1eaff;font-weight:550}.question-number{color:#b1bac9;font-size:10px;line-height:2.1;min-width:17px;font-variant-numeric:tabular-nums;flex-shrink:0}.is-current .question-number{color:#6f95e9}.guide-group{border-top:1px solid #f0f2f6;padding-top:8px}.reading-pane{background:#fff;outline:none;scroll-behavior:smooth}.reader-width{width:100%;max-width:1020px;margin:0 auto;padding:31px 54px 25px}.breadcrumb{display:flex;gap:10px;align-items:center;font-size:10px;color:#a0a9b8;line-height:1.6;margin-bottom:30px}.breadcrumb a:hover{color:var(--blue)}.breadcrumb>span:nth-child(even){color:#d0d6e1}.article-header{padding-bottom:27px;border-bottom:1px solid var(--border);margin-bottom:25px}.article-meta{display:flex;align-items:center;gap:12px;flex-wrap:wrap;font-size:10px;margin-bottom:14px}.source-badge{background:#f2f5fa;padding:5px 8px;border-radius:4px;color:#8390a4}.priority{color:#b88b53;font-size:10px;background:#fbf5eb;padding:4px 7px;border-radius:4px}.scenario-badge{color:#7f78b7;background:#f3f0fb;padding:4px 7px;border-radius:4px}.reading-time{color:#a3adbd;margin-left:auto;font-size:10px}.article-header h1,.results-header h1{margin:0;font-size:27px;font-weight:650;line-height:1.55;letter-spacing:-.6px;color:#202c43;overflow-wrap:anywhere}.article-intro{font-size:12px;color:#9aa4b4;margin:12px 0 0;line-height:1.8}.answer-section{margin:0 0 29px}.section-label{display:flex;gap:8px;align-items:center;font-size:13px;font-weight:650;color:#445675;line-height:1.7;margin:0 0 14px}.label-icon{font-size:16px;line-height:1;color:#6b8ed8}.section-hint{font-size:10px;font-weight:400;color:#a7afbd;margin-left:7px}.key-points{border:1px solid #e5ecfb;background:#f6f9ff;border-radius:9px;padding:19px 22px;margin-bottom:29px}.key-points .section-label{color:#4971c1;font-size:12px;margin-bottom:9px}.key-points .markdown{font-size:13px;line-height:1.95;color:#60708c}.markdown{font-size:14px;line-height:2.1;color:#5c6980;overflow-wrap:anywhere}.markdown>*:first-child{margin-top:0}.markdown>*:last-child{margin-bottom:0}.markdown p{margin:0 0 16px}.markdown a{color:#547eca;text-decoration:underline;text-decoration-color:#d8e3f7;text-underline-offset:3px}.markdown a:hover{text-decoration-color:currentColor}.markdown strong{font-weight:600;color:#455572}.markdown ul,.markdown ol{padding-left:24px;margin:12px 0 17px}.markdown li{margin:6px 0}.markdown h1{font-size:23px}.markdown h2{font-size:18px}.markdown h3{font-size:16px}.markdown h1,.markdown h2,.markdown h3,.markdown h4{line-height:1.8;color:#42536d;margin:25px 0 12px}.markdown blockquote{border-left:3px solid #cfddf6;background:#f8faff;padding:12px 18px;margin:16px 0;color:#7c8ba4}.markdown code{font:12px/1.8 Consolas,"SFMono-Regular","Microsoft YaHei",monospace;background:#f0f3f8;color:#5877aa;padding:2px 5px;border-radius:4px;overflow-wrap:anywhere}.code-frame{border:1px solid #e3e9f2;border-radius:9px;overflow:hidden;margin:18px 0;max-width:100%;background:#f8faff}.code-toolbar{display:flex;align-items:center;justify-content:space-between;min-height:36px;padding:6px 14px;border-bottom:1px solid #e7ecf5;font:10px/1.5 Consolas,monospace;color:#92a0b6;background:#f1f5fb}.copy-code{font-size:10px;color:#6b82a5;background:transparent;padding:3px 6px;border:1px solid #dce5f2;border-radius:4px}.copy-code:hover{background:white;color:var(--blue)}.markdown pre{margin:0;padding:19px 21px;overflow:auto;max-width:100%;tab-size:2;line-height:1.8;color:#536b91}.markdown pre code{font-size:12px;line-height:1.8;background:transparent;padding:0;color:inherit;white-space:pre;overflow-wrap:normal;border-radius:0}.table-scroll{overflow-x:auto;border:1px solid var(--border);border-radius:7px;margin:18px 0;max-width:100%}.markdown table{border-collapse:collapse;min-width:100%;font-size:12px;text-align:left}.markdown th,.markdown td{padding:10px 14px;line-height:1.9;vertical-align:top;border-bottom:1px solid var(--border);min-width:100px}.markdown th{background:#f6f8fc;font-weight:550;color:#64718a}.markdown tr:last-child td{border-bottom:0}.markdown tr:hover td{background:#fbfcfe}.markdown td code{white-space:normal}.followup{border:1px solid #e5eaf3;border-radius:9px;margin:32px 0 0;background:#fff}.followup>summary{display:flex;align-items:center;gap:12px;padding:17px 20px;list-style:none}.followup>summary::-webkit-details-marker{display:none}.followup-symbol{display:grid;place-items:center;border:1px solid #e3e9f5;border-radius:7px;width:30px;height:30px;color:#84a0ce;font-size:18px}.followup summary strong{display:block;font-size:12px;font-weight:550;color:#64738b}.followup summary small{display:block;font-size:10px;color:#a8b0bf;margin-top:5px}.followup-action{margin-left:auto;font-size:10px;color:#8da0bd}.followup[open] .followup-symbol{font-size:0}.followup[open] .followup-symbol::before{content:'−';font-size:18px}.followup-body{border-top:1px solid #edf0f6;padding:22px}.followup-body section+section{margin-top:24px}.pagination{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:14px;margin:34px 0}.pagination a{border:1px solid var(--border);border-radius:8px;padding:16px 18px;min-width:0}.pagination a:hover{border-color:#b9cdf8;background:#fafcff}.pagination span{display:block;font-size:10px;color:#a0acc0;margin-bottom:8px}.pagination strong{display:block;font-size:11px;font-weight:500;color:#65748e;line-height:1.9;overflow-wrap:anywhere}.next-question{text-align:right}.article-footer{display:flex;justify-content:space-between;align-items:center;border-top:1px solid var(--border);padding:20px 0;color:#adb6c4;font-size:9px;gap:10px}.article-footer .status-dot{width:5px;height:5px;background:#a4bbaa}.article-footer a:hover{color:var(--blue)}.source-index{margin-top:30px;border-top:1px solid var(--border);padding-top:25px}.source-index-heading{display:flex;justify-content:space-between;align-items:center;margin:18px 8px 4px;font-size:12px;font-weight:600;color:#5d6b82}.source-index-heading span{font-size:10px;font-weight:400;color:#9aa6b8}.source-index-list{display:grid;gap:3px}.source-index-list a{padding:10px 8px;display:flex;gap:12px;font-size:12px;color:#647695;line-height:1.8;border-radius:5px}.source-index-list a:hover{background:var(--blue-soft)}.source-index-list a span:first-child{color:#a1b0c7;font-size:10px;min-width:13px}.source-index-list a span:last-child{margin-left:auto;color:#9cacbf}.results-header{display:flex;justify-content:space-between;align-items:center;margin:25px 0;gap:15px}.results-header h1{font-size:26px}.results-header p:not(.eyebrow){font-size:12px;color:#8c98ac;line-height:1.9;margin-bottom:0}.text-link{color:#7490bf;font-size:11px;white-space:nowrap}.result-list{display:grid;gap:13px}.result-card{display:block;border:1px solid var(--border);border-radius:9px;padding:20px 22px;transition:border-color .15s}.result-card:hover{border-color:#b5caf8;background:#fbfcff}.result-meta{display:flex;align-items:center;gap:8px;color:#a1acc0;font-size:10px}.result-card h2{display:flex;justify-content:space-between;gap:20px;font-size:15px;line-height:1.8;margin:10px 0;color:#50617e;font-weight:550}.result-card h2>span{color:#9aaeca;font-weight:400}.result-card p{font-size:12px;line-height:1.9;color:#929eb1;margin:0}.empty-state{padding:65px 20px;text-align:center;max-width:600px;margin:auto}.empty-symbol{display:grid;place-items:center;width:55px;height:55px;border-radius:16px;background:var(--blue-soft);color:#7999d8;font-size:30px;margin:0 auto 20px}.empty-state h1,.empty-state h2{font-size:21px;color:#536683}.empty-state p{color:#8b99ad;font-size:13px;line-height:1.9}.primary-link{display:inline-block;margin-top:16px;padding:11px 19px;background:var(--blue);color:white;border-radius:7px;font-size:12px}.toast{position:fixed;bottom:28px;left:50%;transform:translateX(-50%);background:#263c60;color:white;padding:13px 20px;border-radius:9px;z-index:50;font-size:12px;max-width:90vw;box-shadow:0 6px 25px #1e335533}.mobile-navigation{display:none}
@media(min-width:1650px){:root{--directory:320px}.reader-width{padding-left:68px;padding-right:68px}.markdown{font-size:15px}.question-link{font-size:12px}.header-stat{font-size:12px}}
@media(max-width:1250px){.header-stat{display:none}.reader-width{padding:28px 34px}.site-header{gap:24px}.article-header h1{font-size:25px}}
@media(max-width:1060px){:root{--directory:285px}.site-header{gap:15px}.reader-width{padding-left:30px;padding-right:30px}.article-header h1{font-size:24px}.article-intro{font-size:11px}}
@media(max-width:720px){:root{--header:120px}.site-header{display:grid;grid-template-columns:minmax(0,1fr) auto auto;gap:9px 8px;padding:12px 14px;height:var(--header)}.brand{gap:8px;min-width:0}.brand>span:last-child{min-width:0}.brand-mark{flex-shrink:0;width:30px;height:36px;border-radius:9px}.brand-mark svg{width:24px;height:24px}.brand strong{font-size:13px;overflow:hidden;text-overflow:ellipsis}.brand small{font-size:7px;margin-top:3px;letter-spacing:1px}.mobile-navigation{display:block;margin:0}.mobile-navigation>summary{display:flex;align-items:center;gap:6px;border:1px solid #e4eaf4;border-radius:7px;padding:7px 10px;color:#6d82a1;font-size:12px;list-style:none;white-space:nowrap}.mobile-navigation>summary::-webkit-details-marker{display:none}.mobile-navigation:not([open])>.mobile-navigation-content{display:none}.search-form{grid-column:1/-1;grid-row:2;max-width:none;width:100%;height:37px;gap:6px;padding-left:10px}.search-form input{font-size:12px}.search-form select{font-size:10px;max-width:95px;padding-left:4px}.search-submit{font-size:11px;padding:6px 8px}.workspace{display:block}.question-pane{display:none}.reading-pane{height:100%}.reader-width{padding:22px 21px 18px}.breadcrumb{margin-bottom:24px;font-size:10px}.article-meta{gap:8px}.article-header h1{font-size:23px;line-height:1.6}.article-header{padding-bottom:21px;margin-bottom:22px}.article-intro{font-size:11px;line-height:1.9}.reading-time{font-size:9px}.key-points{padding:17px;margin-bottom:25px}.key-points .markdown{font-size:12px}.markdown{font-size:14px;line-height:2.05}.section-label{font-size:12px}.section-hint{font-size:9px;margin-left:2px}.answer-section{margin-bottom:23px}.followup>summary{padding:15px;gap:9px}.followup-body{padding:18px}.followup-action{font-size:9px}.pagination{gap:9px;margin:26px 0}.pagination a{padding:12px}.pagination strong{font-size:10px}.article-footer{font-size:9px;align-items:flex-start;line-height:1.8}.mobile-navigation-content{position:fixed;top:var(--header);bottom:0;left:0;width:100%;background:white;z-index:30;overflow:hidden}.mobile-navigation-content .directory-heading{padding:22px 21px 18px}.category-switcher>summary{gap:5px;min-height:34px;padding:6px 7px}.category-toggle-label{display:none}.category-toggle-title{font-size:11px;max-width:74px}.category-caret{width:15px;height:15px}.category-popover{position:fixed;top:calc(var(--header) - 3px);left:14px;right:14px;width:auto;max-width:none;padding:16px}.category-popover .category-link{font-size:12px;padding:10px}.mobile-navigation-content .question-link{font-size:12px;padding:10px;gap:9px}.results-header h1{font-size:23px}.results-header{align-items:flex-start}.result-card{padding:17px}.result-card h2{font-size:14px}.result-card p{font-size:12px}.code-toolbar{padding-left:12px}.markdown pre{padding:16px}.markdown pre code{font-size:11px}.markdown th,.markdown td{padding:8px 11px}.empty-state{padding:50px 12px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}
.followup-close-label{display:none}.followup[open] .followup-close-label{display:inline}.followup[open] .followup-open-label{display:none}
.answer-navigation{display:flex;flex-wrap:wrap;gap:8px;margin:-6px 0 28px;padding-bottom:18px;border-bottom:1px solid var(--border)}.answer-navigation a{font-size:12px;line-height:1.6;padding:5px 9px;border-radius:5px;background:var(--blue-soft);color:#3865ba}.answer-navigation a:hover{background:#dfeaff}.answer-section,.followup{scroll-margin-top:22px}@media print{.answer-navigation{display:none}}
@media print{.site-header,.question-pane,.pagination,.article-footer,.copy-code,.skip-link{display:none!important}.workspace{display:block;height:auto}.reading-pane{overflow:visible;height:auto}.reader-width{max-width:none;padding:0}.followup:not([open])>.followup-body{display:block}.markdown pre{white-space:pre-wrap}.markdown pre code{white-space:pre-wrap}.code-frame,.answer-section{break-inside:avoid}.article-header{margin-top:0}}