:root {
  --paper: #f7f9fc;
  --paper-deep: #eef2f7;
  --ink: #18212f;
  --muted: #667085;
  --line: #e1e6ee;
  --panel: rgba(255, 255, 255, 0.96);
  --accent: #2563eb;
  --accent-soft: #e8efff;
  --green: #17866f;
  --shadow: 0 18px 60px rgba(24, 33, 47, 0.07);
  --serif: Georgia, "Times New Roman", "Noto Serif SC", serif;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --library-width: 272px;
  --directory-width: 430px;
  --quality-width: 420px;
}

* { box-sizing: border-box; }
html { height: 100%; scroll-behavior: smooth; }
body {
  min-height: 100%; margin: 0; color: var(--ink); background: var(--paper);
  font-family: var(--sans); -webkit-font-smoothing: antialiased;
}
button, input { font: inherit; }
button { color: inherit; }
.paper-grain {
  display: none;
}

.masthead {
  height: 76px; position: sticky; top: 0; z-index: 15; display: grid;
  grid-template-columns: 244px minmax(0, 1fr); align-items: center; gap: 22px;
  padding: 0 28px; border-bottom: 1px solid var(--line); background: rgba(255,255,255,.94);
  backdrop-filter: blur(18px);
}
.brand { display: flex; align-items: center; gap: 12px; color: inherit; text-decoration: none; }
.brand-mark {
  display: grid; place-items: center; width: 38px; height: 38px; border: 1.5px solid var(--ink);
  font: 700 15px/1 var(--serif); letter-spacing: -2px; transform: rotate(-3deg);
}
.brand-mark span { color: var(--accent); }
.brand b { display: block; font-family: var(--serif); font-size: 20px; letter-spacing: -.3px; }
.brand small { display: block; margin-top: 1px; color: var(--muted); font: 9px/1 var(--sans); letter-spacing: 1.7px; text-transform: uppercase; }
.build-status { justify-self: end; color: var(--muted); font-size: 12px; letter-spacing: .4px; }
.build-status span { display: inline-block; width: 6px; height: 6px; margin-right: 8px; border-radius: 50%; background: #63a58d; box-shadow: 0 0 0 4px #dce9df; }
.build-status b { color: var(--ink); }
.header-actions { justify-self: end; display: flex; align-items: center; gap: 17px; }
.layout-controls { display: flex; align-items: center; gap: 3px; padding: 3px; border: 1px solid var(--line); border-radius: 5px; background: #f4f7fb; }
.layout-button { padding: 5px 7px; color: #9aa3b1; border: 0; border-radius: 3px; background: transparent; cursor: pointer; font-size: 9px; }
.layout-button.active { color: var(--ink); background: #fff; box-shadow: 0 1px 5px rgba(24,33,47,.08); }
.layout-button:hover { color: var(--accent); }
.quality-queue-button { padding: 9px 12px; border: 1px solid var(--line); border-radius: 4px; background: #fff; cursor: pointer; color: var(--ink); font-size: 11px; }
.quality-queue-button:hover { border-color: var(--accent); color: var(--accent); }
.quality-queue-button span { display: inline-grid; min-width: 19px; height: 19px; margin-left: 6px; place-items: center; border-radius: 10px; color: #fff; background: var(--accent); font: 9px var(--mono); }

.app-shell {
  --library-column: var(--library-width); --library-gutter: 7px;
  --quality-column: 0px; --quality-gutter: 0px;
  display: grid;
  grid-template-columns: var(--library-column) var(--library-gutter) minmax(0, 1fr) var(--quality-gutter) var(--quality-column);
  min-height: calc(100vh - 76px);
}
body.library-hidden .app-shell { --library-column: 0px; --library-gutter: 0px; }
body.quality-panel-open .app-shell { --quality-column: var(--quality-width); --quality-gutter: 7px; }
.rail {
  grid-column: 1;
  position: sticky; top: 76px; height: calc(100vh - 76px); overflow: auto; display: flex; flex-direction: column;
  min-width: 0; padding: 29px 22px 18px; background: #f3f6fa;
}
body.library-hidden .rail { display: none; }
#library-resizer { grid-column: 2; }
.rail-label { margin: 0 9px 10px; color: #8f8c82; font: 10px/1 var(--mono); letter-spacing: 2px; }
.domain-nav { display: grid; gap: 7px; }
.domain-button {
  width: 100%; display: grid; grid-template-columns: 9px 1fr auto; align-items: center; gap: 11px;
  padding: 13px 10px; text-align: left; border: 0; border-radius: 5px; background: transparent; cursor: pointer;
}
.domain-button:hover { background: rgba(255,255,255,.52); }
.domain-button.active { background: #fff; box-shadow: 0 7px 24px rgba(24,33,47,.06); }
.domain-swatch { width: 8px; height: 34px; border-radius: 1px; background: var(--domain-accent); }
.domain-button b { display: block; font: 600 14px/1.25 var(--sans); }
.domain-button small { display: block; margin-top: 5px; color: var(--muted); font-size: 10px; }
.domain-button > em { color: #8c8b83; font: normal 10px var(--mono); }
.rail-rule { height: 1px; margin: 24px 9px; background: var(--line); }
.chapter-nav { display: grid; gap: 1px; }
.chapter-button {
  display: grid; grid-template-columns: 34px 1fr; gap: 7px; padding: 8px 9px; text-align: left;
  border: 0; border-left: 2px solid transparent; background: transparent; cursor: pointer;
}
.chapter-button:hover, .chapter-button.active { color: var(--accent); border-left-color: var(--accent); background: rgba(255,255,255,.4); }
.chapter-button span { color: #8b8b82; font: 10px/1.5 var(--mono); }
.chapter-button b { font-size: 11px; line-height: 1.4; font-weight: 540; }
.rail-footer { display: flex; align-items: center; gap: 10px; margin-top: auto; padding: 18px 8px 2px; border-top: 1px solid var(--line); }
.status-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--green); }
.rail-footer b, .rail-footer small { display: block; font-size: 10px; }
.rail-footer small { margin-top: 3px; color: var(--muted); }

.workspace {
  grid-column: 3;
  --directory-column: var(--directory-width); --directory-gutter: 7px; --detail-column: minmax(320px, 1fr);
  min-width: 0; display: grid;
  grid-template-columns: var(--directory-column) var(--directory-gutter) var(--detail-column);
}
body.directory-hidden .workspace { --directory-column: 0px; --directory-gutter: 0px; --detail-column: minmax(0, 1fr); }
body.detail-hidden .workspace { --directory-column: minmax(0, 1fr); --directory-gutter: 0px; --detail-column: 0px; }
body.directory-hidden .browser-panel, body.detail-hidden .detail-panel { display: none; }
.browser-panel { grid-column: 1; min-width: 0; height: calc(100vh - 76px); overflow: hidden; display: flex; flex-direction: column; border-right: 1px solid var(--line); }
#directory-resizer { grid-column: 2; }
#detail-panel { grid-column: 3; }
#quality-resizer { grid-column: 4; }
.pane-resizer { position: relative; z-index: 4; width: 7px; min-width: 0; height: calc(100vh - 76px); cursor: col-resize; touch-action: none; background: var(--paper); }
.pane-resizer::after { content: ""; position: absolute; inset: 0 3px; background: var(--line); transition: inset .15s, background .15s; }
.pane-resizer:hover::after, .pane-resizer.dragging::after { inset-inline: 2px; background: var(--accent); }
body.library-hidden #library-resizer, body.directory-hidden #directory-resizer, body.detail-hidden #directory-resizer, body:not(.quality-panel-open) #quality-resizer { display: none; }
body.resizing { cursor: col-resize; user-select: none; }
body.resizing * { cursor: col-resize !important; }
.panel-head { display: flex; justify-content: space-between; align-items: center; padding: 31px 29px 20px; }
.eyebrow { color: var(--accent); font: 10px var(--mono); letter-spacing: 2px; }
.panel-head h1 { margin: 5px 0 0; font: 500 26px/1.1 var(--serif); }
.icon-button { display: grid; place-items: center; width: 34px; height: 34px; border: 1px solid var(--line); border-radius: 50%; background: transparent; cursor: pointer; }
.icon-button:hover { color: var(--accent); border-color: var(--accent); }
.icon-button svg { width: 15px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.tree-view { flex: 1; overflow: auto; padding: 3px 20px 50px 22px; }
.loading-state { min-height: 380px; display: grid; place-content: center; justify-items: center; color: var(--muted); }
.loading-state span { width: 30px; height: 30px; border: 2px solid var(--line); border-top-color: var(--accent); border-radius: 50%; animation: spin .85s linear infinite; }
.loading-state p { font: 11px var(--mono); letter-spacing: 1px; }
@keyframes spin { to { transform: rotate(360deg); } }

.tree-root, .tree-children { list-style: none; margin: 0; padding: 0; }
.tree-children { position: relative; margin-left: 13px; padding-left: 17px; }
.tree-children::before { content: ""; position: absolute; left: 2px; top: 0; bottom: 12px; border-left: 1px solid #d9d3c8; }
.tree-node { position: relative; }
.tree-row { display: grid; grid-template-columns: 18px minmax(0,1fr) auto; align-items: center; gap: 5px; min-height: 38px; padding: 4px 7px 4px 2px; border-radius: 4px; cursor: pointer; }
.tree-row:hover { background: rgba(255,255,255,.56); }
.tree-row.selected { color: var(--accent); background: #fff; box-shadow: inset 2px 0 var(--accent); }
.tree-toggle { display: grid; place-items: center; width: 18px; height: 18px; padding: 0; border: 0; background: transparent; cursor: pointer; }
.tree-toggle::before { content: ""; width: 5px; height: 5px; border-right: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; transform: rotate(-45deg); transition: transform .15s; }
.tree-toggle.open::before { transform: rotate(45deg) translate(-1px,-1px); }
.tree-toggle.leaf::before { width: 4px; height: 4px; border: 0; border-radius: 50%; background: #bbb7ad; }
.tree-label { min-width: 0; }
.tree-label b { display: block; overflow: hidden; color: inherit; font-family: var(--serif); font-size: 13px; font-weight: 500; line-height: 1.25; text-overflow: ellipsis; white-space: nowrap; }
.tree-label small { color: #96938a; font: 9px var(--mono); }
.tree-count { padding: 3px 6px; border-radius: 10px; color: var(--muted); background: #e9eef5; font: 9px var(--mono); }

.detail-panel { height: calc(100vh - 76px); overflow: auto; background: var(--panel); }
.detail-placeholder { min-height: 80vh; display: grid; place-content: center; justify-items: center; color: #9c988f; }
.big-mark { font: italic 64px/1 var(--serif); color: #d2cabd; }
.detail-placeholder p { font-family: var(--serif); }
.topic-hero { position: relative; padding: 41px 45px 30px; border-bottom: 1px solid var(--line); overflow: hidden; }
.breadcrumbs { display: flex; align-items: center; gap: 7px; overflow: hidden; margin-bottom: 20px; color: var(--muted); font: 9px var(--mono); white-space: nowrap; }
.breadcrumbs span { overflow: hidden; text-overflow: ellipsis; }
.breadcrumbs i { color: #b7b0a4; font-style: normal; }
.topic-hero h2 { max-width: 760px; margin: 12px 0 13px; font: 500 clamp(28px,3vw,43px)/1.08 var(--serif); letter-spacing: -.8px; }
.topic-role { max-width: 760px; margin: 0; color: #5f6763; font: 14px/1.7 var(--serif); }
.topic-actions { margin-top: 20px; }
.review-button { display: inline-flex; align-items: center; gap: 6px; padding: 7px 10px; border: 1px solid var(--line); border-radius: 4px; color: var(--muted); background: #fff; cursor: pointer; font-size: 10px; }
.review-button:hover { color: var(--accent); border-color: var(--accent); }
.detail-body { padding: 29px 45px 70px; }
.topic-relations { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; margin-bottom: 31px; padding-bottom: 28px; border-bottom: 1px solid var(--line); }
.relation-group { min-width: 0; }
.relation-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 14px; margin-bottom: 10px; }
.relation-heading h3 { margin: 0; font: 500 15px var(--serif); }
.relation-heading small { color: var(--muted); font: 9px var(--mono); }
.relation-list { display: grid; grid-template-columns: repeat(auto-fit, minmax(155px, 1fr)); gap: 7px; }
.relation-card { width: 100%; min-height: 45px; display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 10px 12px; text-align: left; border: 1px solid var(--line); border-radius: 4px; background: #f8fafc; cursor: pointer; }
.relation-card:hover { color: var(--accent); border-color: var(--accent); background: #fff; }
.relation-card b { font: 500 12px/1.35 var(--serif); }
.relation-card span { flex: 0 0 auto; color: var(--accent); font-size: 13px; }
.section-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 20px; margin-bottom: 15px; }
.section-heading h3 { margin: 0; font: 500 18px var(--serif); }
.section-heading span { color: var(--muted); font: 9px var(--mono); }
.statement-list { display: grid; gap: 13px; }
.statement-card { border: 1px solid var(--line); border-radius: 5px; background: rgba(255,255,255,.58); box-shadow: 0 9px 26px rgba(47,42,34,.035); }
.statement-card[open] { background: #fff; }
.statement-card summary { display: block; padding: 15px 16px; list-style: none; cursor: pointer; }
.statement-card summary::-webkit-details-marker { display: none; }
.statement-card summary b { font: 500 14px/1.3 var(--serif); }
.statement-content { padding: 0 17px 19px; border-top: 1px solid #e8e2d8; }
.statement-tools { display: flex; justify-content: flex-end; padding-top: 12px; }
.plain-statement { margin: 16px 0; font: 15px/1.7 var(--serif); }
.formal-block { overflow-x: auto; margin: 15px 0; padding: 16px; border-left: 2px solid var(--accent); color: #263142; background: #f3f6fa; font-size: 13px; }
.statement-meta { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 10px 16px; margin-top: 16px; }
.meta-block { min-width: 0; }
.meta-block.full { grid-column: 1 / -1; }
.meta-block label { display: block; margin-bottom: 4px; color: #969187; font: 8px var(--mono); letter-spacing: 1px; text-transform: uppercase; }
.meta-block p, .meta-block ul { margin: 0; color: var(--muted); font-size: 11px; line-height: 1.55; }
.meta-block ul { padding-left: 16px; }
.latex-value { max-width: 100%; overflow-x: auto; color: var(--muted); font-size: 11px; line-height: 1.65; }
.latex-list li { margin: 3px 0; }
.notation-symbol { display: inline-block; margin-right: 7px; color: var(--ink); }
.notation-symbol + span { color: var(--muted); }
.prerequisite-links { display: flex; flex-wrap: wrap; align-items: center; gap: 5px 8px; }
.prerequisite-links a { color: var(--accent); text-decoration: none; border-bottom: 1px solid color-mix(in srgb, var(--accent) 32%, transparent); font-family: var(--mono); font-size: 10px; }
.prerequisite-links a:hover { border-bottom-color: var(--accent); }
.prerequisite-links span { color: #a5adba; }
.source-list { display: grid; gap: 8px; }
.source-item { padding: 10px; border: 1px solid var(--line); background: #f6f8fb; }
.source-item b { display: block; margin-bottom: 3px; font-size: 10px; }
.source-item span { color: var(--muted); font: 9px/1.45 var(--mono); }
.empty-statements { padding: 30px; text-align: center; color: var(--muted); border: 1px dashed var(--line); }
.empty-statements b { display: block; margin-bottom: 6px; font: 500 17px var(--serif); color: var(--ink); }
.witness-section { margin-top: 30px; padding-top: 24px; border-top: 1px solid var(--line); }
.toast { position: fixed; right: 26px; bottom: 24px; z-index: 50; transform: translateY(20px); padding: 11px 15px; color: #fff; background: var(--ink); border-radius: 4px; opacity: 0; pointer-events: none; font-size: 11px; transition: .2s; }
.toast.show { transform: translateY(0); opacity: 1; }

.quality-panel { grid-column: 5; display: none; min-width: 0; height: calc(100vh - 76px); overflow: auto; border-left: 1px solid var(--line); background: #fff; box-shadow: -14px 0 45px rgba(24,33,47,.06); }
body.quality-panel-open .quality-panel { display: block; }
.quality-view { min-height: 100%; padding: 25px; }
.quality-view > header, .quality-view form > header { display: flex; justify-content: space-between; align-items: flex-start; gap: 20px; }
.quality-view h2 { margin: 5px 0 0; font: 500 25px/1.1 var(--serif); }
.quality-view .icon-button { flex: 0 0 auto; font: 19px/1 var(--sans); }
.quality-intro { margin: 20px 0; color: var(--muted); font-size: 11px; line-height: 1.6; }
.quality-toolbar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 18px; }
.primary-button, .secondary-button, .text-button { border-radius: 4px; cursor: pointer; font-size: 11px; }
.primary-button { padding: 10px 14px; color: #fff; border: 1px solid var(--accent); background: var(--accent); }
.primary-button:hover { filter: brightness(.94); }
.secondary-button { padding: 9px 12px; color: var(--ink); border: 1px solid var(--line); background: #fff; }
.secondary-button:hover { border-color: var(--accent); color: var(--accent); }
.text-button { padding: 8px; color: var(--muted); border: 0; background: transparent; }
.text-button:hover { color: var(--accent); }
.quality-issue-list { display: grid; gap: 10px; }
.quality-issue-card { padding: 14px; border: 1px solid var(--line); border-radius: 5px; background: #f8fafc; }
.quality-issue-card.resolved { opacity: .58; }
.quality-issue-top { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.severity-badge { color: var(--accent); font: 9px var(--mono); letter-spacing: .8px; text-transform: uppercase; }
.quality-issue-card h3 { margin: 8px 0 5px; font: 500 14px/1.3 var(--serif); }
.quality-issue-kind { color: var(--muted); font: 9px var(--mono); text-transform: uppercase; }
.quality-issue-card p { margin: 9px 0; color: var(--muted); font-size: 11px; line-height: 1.55; }
.quality-card-actions { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-top: 12px; }
.quality-card-actions button { padding: 0; border: 0; color: var(--accent); background: transparent; cursor: pointer; font-size: 10px; }
.quality-card-actions button:last-child { color: var(--muted); }
.quality-empty { padding: 36px 18px; text-align: center; color: var(--muted); border: 1px dashed var(--line); font-size: 11px; line-height: 1.6; }

.quality-view form { min-width: 0; }
.quality-target { margin: 20px 0; padding: 12px 14px; border-left: 2px solid var(--accent); background: #f4f7fb; }
.quality-target b { display: block; font: 500 14px/1.35 var(--serif); }
.quality-target span { display: block; overflow: hidden; margin-top: 5px; color: var(--muted); font: 9px var(--mono); text-overflow: ellipsis; white-space: nowrap; }
.form-field { display: grid; gap: 7px; margin-top: 15px; }
.form-field > span { color: var(--muted); font: 9px var(--mono); letter-spacing: .8px; text-transform: uppercase; }
.form-field select, .form-field textarea { width: 100%; padding: 10px 11px; color: var(--ink); border: 1px solid var(--line); border-radius: 4px; outline: 0; background: #fff; font-size: 12px; }
.form-field textarea { resize: vertical; line-height: 1.55; }
.form-field select:focus, .form-field textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 12%, transparent); }
.quality-view footer { display: flex; justify-content: flex-end; align-items: center; gap: 9px; margin-top: 22px; }

@media (max-width: 1180px) {
  .masthead { grid-template-columns: 220px minmax(0,1fr); gap: 15px; }
  .build-status { display: none; }
  :root { --library-width: 235px; --directory-width: 390px; --quality-width: 370px; }
  .topic-hero, .detail-body { padding-inline: 30px; }
}
@media (min-width: 881px) and (max-width: 1094px) {
  :root { --directory-width: clamp(280px, 30vw, 340px); --quality-width: 320px; }
  .workspace { --detail-column: minmax(260px, 1fr); }
}
@media (max-width: 880px) {
  .masthead { grid-template-columns: auto minmax(0,1fr); height: 68px; padding: 0 15px; gap: 15px; }
  .brand small, .brand > span:last-child { display: none; }
  .layout-controls { display: none; }
  .quality-queue-button { font-size: 0; }
  .quality-queue-button span { margin-left: 0; font-size: 9px; }
  .app-shell { display: block; }
  .pane-resizer { display: none !important; }
  .rail { position: static; width: 100%; height: auto; padding: 12px 14px; border-right: 0; border-bottom: 1px solid var(--line); }
  .rail-label, .rail-rule, .chapter-nav, .rail-footer { display: none; }
  .domain-nav { grid-template-columns: repeat(2,1fr); }
  .domain-button { padding: 7px; }
  .workspace { display: block; }
  .browser-panel, .detail-panel { height: auto; min-height: calc(100vh - 150px); border-right: 0; }
  .detail-panel { border-top: 1px solid var(--line); }
  .tree-view { min-height: 55vh; max-height: 70vh; }
  .topic-hero, .detail-body { padding-inline: 22px; }
  .statement-meta { grid-template-columns: 1fr; }
  .meta-block.full { grid-column: auto; }
  .quality-panel { position: fixed; inset: 68px 0 0 auto; z-index: 30; width: min(94vw, 460px); height: calc(100vh - 68px); box-shadow: -20px 0 60px rgba(24,33,47,.18); }
}
@media (max-width: 560px) {
  .domain-button > em { display: none; }
  .panel-head { padding: 24px 20px 17px; }
  .tree-view { padding-inline: 12px; }
  .topic-hero h2 { font-size: 30px; }
}