/* The research reader shares the site's shell and typography. */
.zhihu-research { --zr-teal: #176d69; --zr-ochre: #936223; --zr-tint: #edf4f2; }
:root[data-theme="dark"] .zhihu-research { --zr-teal: #8dcec4; --zr-ochre: #e6b877; --zr-tint: #1d2c29; }
.zr-main { max-width: 1512px; padding: 0 var(--pad); margin: 0 auto; }
.zr-main h1, .zr-main h2, .zr-main h3, .zr-main h4, .zr-main p { margin: 0; }
.zr-main a:focus-visible, .zr-main button:focus-visible, .zr-main select:focus-visible, .zr-main summary:focus-visible { outline: 2px solid var(--zr-teal); outline-offset: 4px; }
.zr-main a:hover { color: var(--zr-teal); }
.zr-hero { display: grid; grid-template-columns: .85fr 1.5fr; gap: 5%; padding: 36px 0 46px; align-items: center; }
.zr-back { display: inline-block; color: var(--muted); font-size: 13px; margin-bottom: 48px; }
.zr-eyebrow, .zr-index { font: 11px/1.5 var(--mono); letter-spacing: .08em; color: var(--muted); }
.zr-hero h1 { font-size: clamp(40px, 4.2vw, 62px); font-weight: 500; line-height: 1.13; letter-spacing: -.055em; margin: 18px 0 26px; }
:root[data-lang="zh"] .zr-hero h1 { letter-spacing: -.035em; line-height: 1.25; }
.zr-lede { font-size: 17px; line-height: 1.85; max-width: 36em; color: var(--ink-2); }
.zr-hero .zr-edition { font-size: 11px; line-height: 1.8; color: var(--muted); margin-top: 24px; }
.zr-hero-network { display: block; position: relative; background: #111d2b; color: #dce7ef; overflow: hidden; }
.zr-hero-network img { display: block; width: 100%; height: auto; }
.zr-hero-network-label { position: absolute; bottom: 18px; left: 22px; right: 22px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px; font: 11px/1.6 var(--mono); }
.zr-hero-network:hover { color: #fff !important; }
.zr-context { display: flex; flex-wrap: wrap; align-items: baseline; column-gap: 40px; row-gap: 10px; padding: 22px 0; border-top: 1px solid var(--line); font-size: 12px; color: var(--muted); }
.zr-context strong { font: 18px var(--mono); color: var(--ink); margin-right: 6px; }
.zr-context > span:last-child { margin-left: auto; }
.zr-jump { display: grid; grid-template-columns: repeat(4, 1fr); border-block: 1px solid var(--ink); }
.zr-jump a { min-height: 72px; display: flex; gap: 12px; align-items: center; font-size: 14px; padding: 16px 20px; border-right: 1px solid var(--line); }
.zr-jump a:first-child { padding-left: 0; }
.zr-jump a:last-child { border-right: 0; }
.zr-jump a > span:first-child { color: var(--muted); font: 11px var(--mono); }
.zr-jump a > span:last-child { margin-left: auto; }
.zr-section { display: grid; grid-template-columns: 1fr 2.2fr; gap: 7%; padding: 80px 0; border-bottom: 1px solid var(--line); scroll-margin-top: 96px; }
.zr-question h2 { font-size: clamp(24px, 2.6vw, 36px); font-weight: 500; line-height: 1.35; letter-spacing: -.035em; margin: 20px 0; text-wrap: balance; }
.zr-question p, .zr-method p, .zr-sources p { color: var(--ink-2); font-size: 14px; line-height: 1.9; }
.zr-evidence { min-width: 0; }
.zr-only-js { display: none !important; }
.zr-ready .zr-only-js { display: flex !important; }
.zr-main [hidden] { display: none !important; }
.zr-controls { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 24px; }
.zr-controls button { font: 13px/1.4 var(--font); border: 1px solid var(--line-2); background: var(--bg); color: var(--ink-2); min-height: 44px; padding: 10px 16px; border-radius: 3px; cursor: pointer; }
.zr-controls button[aria-pressed="true"] { color: var(--on-ink); border-color: var(--ink); background: var(--ink); }
.zr-controls button:hover { border-color: var(--zr-teal); }
.zr-profile { margin-bottom: 20px; }
.zr-figure-head { display: flex; align-items: baseline; justify-content: space-between; flex-wrap: wrap; gap: 8px; margin-bottom: 26px; }
.zr-main h3 { font-size: 17px; font-weight: 500; line-height: 1.5; }
.zr-unit { font-size: 11px; color: var(--muted); }
.zr-stat-chart { padding: 10px 0; }
.zr-stat-line { display: grid; grid-template-columns: 70px 1fr 84px; gap: 12px; align-items: center; margin: 18px 0; font-size: 13px; }
.zr-stat-line strong { font: 16px var(--mono); text-align: right; }
.zr-rail { height: 27px; border-left: 1px solid var(--line-2); }
.zr-bar { height: 100%; display: block; background: var(--zr-teal); }
.zr-ochre { background: var(--zr-ochre); }
.zr-ratio { display: flex; align-items: center; gap: 22px; padding: 22px 0; }
.zr-ratio > strong { color: var(--zr-teal); font-size: 46px; letter-spacing: -.04em; font-weight: 400; line-height: 1.1; }
.zr-ratio small { font-size: .6em; }
.zr-ratio > span { font-size: 13px; color: var(--ink-2); }
.zr-main .zr-note { font-size: 12px; color: var(--muted); line-height: 1.85; }
.zr-detail { border-top: 1px solid var(--line); padding: 14px 0; margin-top: 16px; font-size: 13px; }
.zr-detail summary { padding: 5px 0; cursor: pointer; }
.zr-detail p { font-size: 13px; line-height: 1.9; color: var(--ink-2); margin: 16px 0; }
.zr-detail a { display: inline-block; margin-top: 12px; text-decoration: underline; text-underline-offset: 4px; }
.zr-original { margin: 24px 0 0; }
.zr-original img { display: block; width: 100%; height: auto; max-width: 680px; background: white; }
.zr-original figcaption { font-size: 12px; color: var(--muted); margin-top: 12px; line-height: 1.8; }
.zr-table-wrap { max-width: 100%; overflow-x: auto; }
.zr-main table { border-collapse: collapse; width: 100%; font-size: 12px; }
.zr-main caption { text-align: left; color: var(--muted); font-size: 11px; padding: 16px 0; }
.zr-main th, .zr-main td { text-align: right; border-bottom: 1px solid var(--line); padding: 12px 10px; white-space: nowrap; font-variant-numeric: tabular-nums; }
.zr-main th { font-weight: 500; }
.zr-main th:first-child { text-align: left; padding-left: 0; }
.zr-main thead { color: var(--muted); }
.zr-cohorts { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin-bottom: 18px; }
.zr-cohort { border-top: 3px solid var(--line-2); padding: 18px 0 0; }
.zr-cohort[data-active="true"] { border-top-color: var(--zr-teal); }
.zr-cohort h3 { font: 17px var(--mono); }
.zr-cohort h3 > span { display: block; font: 12px/1.8 var(--font); color: var(--muted); margin-top: 5px; }
.zr-density { margin: 22px 0 14px; }
.zr-density strong { font-size: 47px; line-height: 1; font-weight: 400; letter-spacing: -.04em; }
.zr-density strong small { font-size: .5em; }
.zr-density > span { display: block; font-size: 11px; line-height: 1.7; color: var(--muted); margin-top: 9px; }
.zr-density-track { height: 9px; background: var(--fill-2); }
.zr-density-track > span { display: block; height: 100%; background: var(--zr-teal); }
.zr-cohort:nth-child(2) .zr-density-track > span { background: var(--zr-ochre); }
.zr-cohort dl { margin: 22px 0 0; }
.zr-cohort dl > div { display: flex; justify-content: space-between; gap: 8px; margin: 14px 0; align-items: baseline; font-size: 12px; }
.zr-cohort dt { color: var(--muted); }
.zr-cohort dd { margin: 0; font: 13px var(--mono); white-space: nowrap; }
.zr-path-demo { margin-top: 32px; padding: 24px; background: var(--fill); }
.zr-path-demo .zr-figure-head { margin-bottom: 5px; }
.zr-path { display: block; width: 100%; max-width: 580px; margin: 0 auto; }
.zr-path circle { fill: var(--bg); stroke: var(--line-2); stroke-width: 1; }
.zr-path text { fill: var(--ink); font: 14px var(--mono); }
.zr-path-edge { fill: none; stroke: var(--line-2); stroke-width: 2; color: var(--line-2); }
.zr-path-edge[data-lit="true"] { stroke: var(--zr-teal); color: var(--zr-teal); }
.zr-path-result { font-size: 12px; line-height: 1.8; }
.zr-path-demo .zr-controls { margin-bottom: 16px; }
.zr-select { display: flex; align-items: center; gap: 12px; font-size: 12px; color: var(--muted); margin-bottom: 20px; }
.zr-select select { max-width: 100%; font: 13px var(--font); color: var(--ink); background: var(--bg); border: 1px solid var(--line-2); border-radius: 3px; min-height: 44px; padding: 8px 34px 8px 12px; }
.zr-subtitle { margin-bottom: 24px !important; }
.zr-rank-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 22px; margin-bottom: 24px; }
.zr-rank-list { min-width: 0; }
.zr-rank-list h4 { font-size: 17px; font-weight: 500; }
.zr-rank-list > p { color: var(--muted); font-size: 11px; line-height: 1.7; margin: 8px 0 18px; min-height: 38px; }
.zr-rank-list ol { padding: 0; margin: 0; list-style: none; }
.zr-rank-list li { display: grid; grid-template-columns: 14px 1fr; gap: 4px 8px; align-items: baseline; padding: 12px 3px; border-top: 1px solid var(--line); font-size: 13px; }
.zr-rank { font: 11px var(--mono); color: var(--muted); }
.zr-score { grid-column: 2; font: 11px var(--mono); color: var(--muted); }
.zr-rank-list li[data-selected="true"] { background: var(--zr-tint); box-shadow: inset 3px 0 var(--zr-teal); padding-left: 10px; color: var(--zr-teal); }
.zr-topic-head { display: flex; gap: 16px; justify-content: space-between; flex-wrap: wrap; align-items: baseline; }
.zr-topics { table-layout: fixed; }
.zr-topics th:first-child { width: 34%; white-space: normal; line-height: 1.6; }
.zr-topics th, .zr-topics td { padding-top: 9px; padding-bottom: 9px; }
.zr-dot { display: inline-block; width: 7px; height: 7px; background: var(--zr-teal); vertical-align: middle; margin-left: 5px; }
.zr-dot.zr-ochre { background: var(--zr-ochre); }
.zr-topic-count { height: 30px; display: grid; grid-template-columns: minmax(0,1fr) 68px; gap: 6px; align-items: center; }
.zr-topic-count > span:last-child { font-size: 11px; }
.zr-topic-track { display: block; height: 6px; }
.zr-topic-bar { display: block; height: 100%; background: var(--zr-teal); }
.zr-topics td:nth-child(3) .zr-topic-bar { background: var(--zr-ochre); }
.zr-topics + .zr-note { margin-top: 16px; }
.zr-method { padding: 70px 0; border-bottom: 1px solid var(--line); }
.zr-method h2, .zr-sources h2 { font-size: 30px; font-weight: 500; letter-spacing: -.025em; margin: 18px 0 32px; }
.zr-method-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 48px; }
.zr-method h3 { margin-bottom: 14px; }
.zr-sources { padding: 50px 0 80px; }
.zr-sources > p { max-width: 64em; }
.zr-source-links { display: flex; flex-wrap: wrap; gap: 12px 28px; margin-top: 24px; font-size: 13px; }
.zr-source-links a { min-height: 44px; display: inline-flex; align-items: center; gap: 6px; text-decoration: underline; text-underline-offset: 5px; }
@media (max-width: 1100px) { .zr-section { gap: 5%; grid-template-columns: 1fr 2.5fr; } .zr-rank-grid { gap: 14px; } .zr-context > span:last-child { margin-left: 0; } }
@media (max-width: 759.98px) {
    .zr-hero { grid-template-columns: 1fr; gap: 30px; padding: 28px 0 30px; }
    .zr-back { margin-bottom: 28px; }
    .zr-hero h1 { font-size: clamp(40px,8vw,58px); margin: 14px 0 20px; }
    .zr-lede { font-size: 15px; }
    .zr-hero-network-label { left: 14px; right: 14px; bottom: 12px; font-size: 9px; gap: 3px; }
    .zr-context { gap: 12px 24px; }
    .zr-jump { grid-template-columns: 1fr 1fr; }
    .zr-jump a { min-height: 58px; font-size: 13px; padding: 12px; }
    .zr-jump a:nth-child(2) { border-right: 0; }
    .zr-jump a:nth-child(3) { padding-left: 0; }
    .zr-jump a:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
    .zr-section { grid-template-columns: 1fr; gap: 28px; padding: 46px 0; }
    .zr-question h2 { font-size: 28px; margin: 12px 0; text-wrap: initial; }
    .zr-question p { max-width: 42em; }
    .zr-controls { margin-bottom: 20px; }
    .zr-controls button { padding: 10px 13px; }
    .zr-stat-line { grid-template-columns: 52px 1fr 72px; gap: 8px; }
    .zr-stat-line strong { font-size: 14px; }
    .zr-cohorts { gap: 20px; }
    .zr-cohort h3 > span { font-size: 11px; }
    .zr-cohort dl > div { display: block; }
    .zr-cohort dd { margin-top: 4px; font-size: 14px; }
    .zr-path-demo { padding: 18px; }
    .zr-path-demo h3 { font-size: 15px; }
    .zr-rank-grid { grid-template-columns: 1fr; gap: 26px; }
    .zr-rank-list > p { min-height: 0; margin: 6px 0 12px; }
    .zr-rank-list li { grid-template-columns: 20px 1fr 65px; min-height: 44px; align-items: center; }
    .zr-score { grid-column: 3; text-align: right; }
    .zr-topics th:first-child { width: 38%; }
    .zr-main th, .zr-main td { padding-right: 6px; padding-left: 6px; }
    .zr-topics .zr-topic-count { display: flex; flex-direction: column-reverse; align-items: flex-end; justify-content: center; gap: 5px; height: 34px; }
    .zr-topics .zr-topic-track { width: 100%; height: 4px; }
    .zr-topics .zr-topic-count > span:last-child { font-size: 11px; }
    .zr-method { padding: 46px 0; }
    .zr-method-grid { grid-template-columns: 1fr; gap: 28px; }
    .zr-method h2, .zr-sources h2 { font-size: 26px; margin-bottom: 24px; }
    .zr-source-links { display: grid; }
    .zr-sources { padding: 36px 0 48px; }
}
@media print { .zr-only-js, .zr-jump { display: none !important; } .zr-main [hidden] { display: block !important; } .zr-section { break-inside: avoid; } .zr-main { padding: 0; } .zr-hero { padding-top: 0; } }

.zr-distribution { margin-top: 14px; padding-top: 24px; border-top: 1px solid var(--line); }
.zr-distribution h4 { font-size: 15px; font-weight: 500; }
.zr-distribution .zr-figure-head { margin-bottom: 16px; }
.zr-bin-key { display: flex; justify-content: space-between; gap: 12px; font-size: 11px; color: var(--muted); }
.zr-distribution dl { margin: 12px 0 20px; }
.zr-bin { display: grid; grid-template-columns: 116px 1fr; align-items: center; gap: 14px; min-height: 36px; }
.zr-bin dt { font: 12px var(--mono); color: var(--ink-2); }
.zr-bin dd { display: grid; grid-template-columns: minmax(0,1fr) 112px; align-items: center; gap: 12px; margin: 0; }
.zr-bin-track { display: block; height: 15px; }
.zr-bin-track > span { display: block; height: 100%; background: var(--zr-teal); }
.zr-bin-value { text-align: right; font: 12px var(--mono); white-space: nowrap; }
.zr-bin-value small { display: inline-block; width: 56px; font: 11px var(--mono); color: var(--muted); }
@media (max-width: 759.98px) {
    .zr-bin { grid-template-columns: 94px 1fr; gap: 8px; min-height: 42px; }
    .zr-bin dt { font-size: 10px; }
    .zr-bin dd { grid-template-columns: minmax(0,1fr) 52px; gap: 8px; }
    .zr-bin-value small { display: block; width: auto; font-size: 10px; margin-top: 3px; }
}

/* The network is the primary reading surface, with an on-demand neighbour view. */
#network { display: block; }
#network > .zr-question { display: grid; grid-template-columns: 1fr 1fr; gap: 0 8%; align-items: end; margin-bottom: 30px; }
#network .zr-question .zr-index { grid-column: 1 / -1; }
#network .zr-question h2 { margin-bottom: 0; }
.zr-network-bar { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 20px; }
.zr-network-bar .zr-controls { margin-bottom: 16px; }
.zr-network-workspace { display: grid; grid-template-columns: minmax(0,1fr) 260px; border: 1px solid var(--line-2); }
.zr-network-stage { background: #111d2b; color: #dce7ef; position: relative; min-width: 0; scroll-margin-top: 96px; }
.zr-network-stage figure { margin: 0; position: relative; }
.zr-network-stage figure img { display: block; width: 100%; height: auto; }
.zr-network-stage figcaption { padding: 10px 18px 18px; font: 11px/1.6 var(--mono); }
.zr-network-stage canvas { display: none; width: 100%; height: 620px; touch-action: pan-y pinch-zoom; outline-offset: -4px; }
.zr-network-loaded canvas { display: block; }
.zr-network-loaded [data-graph-fallback] { display: none; }
:root.js .zr-main:not([data-graph-cohort="Net10k"]) [data-graph-fallback="Net10k"] { display: none; }
.zr-network-reader:not(.zr-network-loaded) .zr-network-caption { display: none; }
.zr-ready .zr-network-reader:not(.zr-network-loaded) .zr-network-tools,
.zr-ready .zr-network-reader:not(.zr-network-loaded) .zr-view-controls,
.zr-ready .zr-network-reader:not(.zr-network-loaded) .zr-anchor-picker,
.zr-ready .zr-network-reader:not(.zr-network-loaded) #zr-node-form { display: none !important; }
.zr-network-tools { position: absolute; top: 16px; left: 16px; gap: 5px; }
.zr-network-tools button { min-width: 44px; min-height: 44px; padding: 9px; border: 1px solid #425666; background: #162635; color: #dce7ef; font: 13px var(--font); cursor: pointer; }
.zr-network-tools button:hover { background: #243b4d; }
.zr-network-caption { position: absolute; bottom: 16px; left: 18px; right: 18px; display: flex; flex-wrap: wrap; gap: 6px 24px; justify-content: space-between; font: 11px/1.7 var(--mono); color: #b4c9d6; pointer-events: none; }
.zr-node-inspector { padding: 28px 24px; border-left: 1px solid var(--line-2); }
.zr-node-inspector h3 { font-size: 24px; margin: 16px 0 12px; }
.zr-node-inspector > p:not(.zr-eyebrow) { font-size: 12px; color: var(--muted); line-height: 1.85; }
#zr-node-stats { margin: 22px 0; }
#zr-node-stats > div { display: flex; justify-content: space-between; align-items: baseline; gap: 8px; padding: 10px 0; border-bottom: 1px solid var(--line); }
#zr-node-stats dt { font-size: 12px; color: var(--muted); }
#zr-node-stats dd { margin: 0; font: 19px var(--mono); color: var(--ink); }
.zr-ready #zr-node-form { display: block !important; }
#zr-node-form label { display: block; font-size: 11px; color: var(--muted); margin-bottom: 8px; }
#zr-node-form > div { display: flex; gap: 6px; }
#zr-node-form input { min-width: 0; width: 100%; border: 1px solid var(--line-2); background: var(--bg); color: var(--ink); padding: 10px; font: 13px var(--mono); }
#zr-node-form button { min-height: 44px; font: 12px var(--font); border: 1px solid var(--line-2); color: var(--ink); background: var(--fill); padding: 10px 14px; white-space: nowrap; cursor: pointer; }
#zr-node-form > button { width: 100%; margin-top: 8px; background: var(--bg); }
.zr-network-key { display: grid; gap: 10px; margin: 28px 0 20px; font: 11px/1.5 var(--mono); color: var(--ink-2); }
.zr-network-key > span { display: flex; gap: 8px; align-items: center; }
.zr-network-key i { display: inline-block; width: 8px; height: 8px; border-radius: 50%; border: 1px solid #405363; }
.zr-ready .zr-anchor-picker { display: block !important; font-size: 11px; color: var(--muted); margin: 18px 0; }
.zr-anchor-picker select { display: block; width: 100%; min-height: 44px; padding: 9px; margin-top: 8px; color: var(--ink); background: var(--bg); border: 1px solid var(--line-2); font: 13px var(--font); }
.zr-person-network { min-height: 44px; background: var(--zr-tint); color: var(--zr-teal); border: 1px solid var(--line-2); padding: 10px 16px; margin-bottom: 20px; font: 13px var(--font); cursor: pointer; }
.zr-network-reader .zr-network-method { margin: 18px 0 8px; font-size: 13px; line-height: 1.85; color: var(--ink-2); }
:root:not(.js) .zr-node-inspector, :root:not(.js) .zr-network-caption { display: none; }
:root:not(.js) .zr-network-workspace { grid-template-columns: 1fr; }
@media (max-width: 1100px) { .zr-network-workspace { grid-template-columns: minmax(0,1fr) 220px; } .zr-node-inspector { padding: 24px 18px; } }
@media (max-width: 759.98px) {
    #network > .zr-question { grid-template-columns: 1fr; gap: 12px; margin-bottom: 24px; }
    .zr-network-workspace { grid-template-columns: 1fr; }
    .zr-network-stage canvas { height: 420px; }
    .zr-network-caption { left: 12px; right: 12px; bottom: 12px; font-size: 9px; gap: 2px; }
    .zr-network-tools { top: 10px; left: 10px; }
    .zr-node-inspector { padding: 24px 18px; border-left: 0; border-top: 1px solid var(--line-2); }
    .zr-node-inspector h3 { margin: 10px 0; }
    #zr-node-stats { display: grid; grid-template-columns: repeat(3,1fr); gap: 10px; margin: 18px 0; }
    #zr-node-stats > div { display: block; padding-bottom: 12px; }
    #zr-node-stats dd { font-size: 17px; margin-top: 8px; }
    .zr-network-key { display: flex; flex-wrap: wrap; gap: 12px 20px; margin: 20px 0 12px; }
    .zr-network-method { font-size: 12px; }
}
@media print { .zr-network-stage canvas, .zr-node-inspector, .zr-network-caption { display: none !important; } .zr-network-stage [data-graph-fallback] { display: block !important; } .zr-network-workspace { display: block; } }