/* ==========================================================================
   seiflden.com v3 — library.css
   «مكتبة هندسة الإيرادات / The Revenue Engineering Library»: hub (map, questions,
   reading paths) + the three Lab pages. Loaded after site.css. Logical properties
   only (RTL from dir="rtl"); theme tokens only, so both themes work.
   Without JS the whole tree is a nested list, fully expanded, and all three
   panels render one after another. library.js adds tabs, collapse/expand,
   keyboard navigation, focus/hover highlights and, at >= 1024px, the
   horizontal tree (class .is-tree).
   ========================================================================== */

html[lang="en"] [lang="ar"], html[lang="en"] [lang="ar"] * {
  font-family: system-ui, -apple-system, "Segoe UI", Tahoma, "Geeza Pro", sans-serif;
  letter-spacing: 0;
}
.no-js .js-only { display: none !important; }
[hidden] { display: none !important; }

/* ---------- Shared ---------- */
.crumbs { margin-block-end: var(--sp-5); font-size: .8125rem; color: var(--t3); }
:lang(ar) .crumbs { font-size: .875rem; }
.crumbs ol { display: flex; flex-wrap: wrap; align-items: center; }
.crumbs li { display: inline-flex; align-items: center; min-width: 0; }
.crumbs li + li::before { content: "/"; margin-inline: 8px; color: var(--b2); }
.crumbs a { display: inline-flex; align-items: center; min-height: 24px; color: var(--t3); }
.crumbs a:hover { color: var(--t1); }
.crumbs a[aria-current="page"] { color: var(--t2); }

.lib-code {
  display: inline-flex; align-items: center;
  font-size: .75rem; font-weight: 600; line-height: 1.3;
  color: var(--acc); font-variant-numeric: tabular-nums; white-space: nowrap;
}
.lib-dot {
  display: inline-block; flex: none;
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--acc);
}
.lib-dot[data-status="method-first"] { background: linear-gradient(90deg, var(--amber) 50%, transparent 50%); box-shadow: inset 0 0 0 1.5px var(--amber); }
:root[dir="rtl"] .lib-dot[data-status="method-first"], [dir="rtl"] .lib-dot[data-status="method-first"] { background: linear-gradient(270deg, var(--amber) 50%, transparent 50%); }

/* ---------- Hero ---------- */
.lib-hero { position: relative; overflow: hidden; padding-block: var(--sp-7); border-block-end: 1px solid var(--b1); }
.lib-hero--lab { padding-block: var(--sp-7) var(--sp-6); }
.lib-grid-bg {
  position: absolute; inset: 0; pointer-events: none;
  background-image: linear-gradient(var(--grid-line) 1px, transparent 1px), linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 48px 48px;
  -webkit-mask-image: radial-gradient(ellipse 70% 90% at 70% 0%, #000 20%, transparent 75%);
  mask-image: radial-gradient(ellipse 70% 90% at 70% 0%, #000 20%, transparent 75%);
}
.lib-hero .container { position: relative; }
.lib-kicker { margin-block-end: var(--sp-3); font-size: .8125rem; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--acc); }
:lang(ar) .lib-kicker { letter-spacing: 0; text-transform: none; font-size: .9375rem; }
.lib-h1 { font-size: var(--fs-h1); line-height: var(--lh-h); font-weight: 700; letter-spacing: -0.03em; }
:lang(ar) .lib-h1 { font-size: clamp(2.125rem, 1.5rem + 2.4vw, 3.5rem); line-height: 1.3; letter-spacing: 0; }
.lib-h1--lab { font-size: var(--fs-h2); }
:lang(ar) .lib-h1--lab { font-size: clamp(1.875rem, 1.4rem + 1.6vw, 2.75rem); }
.lib-line { margin-block-start: var(--sp-4); font-size: clamp(1.25rem, 1.1rem + .6vw, 1.625rem); font-weight: 650; color: var(--t1); }
.lib-lead { margin-block-start: var(--sp-4); max-width: 62ch; font-size: clamp(1.0625rem, 1rem + .4vw, 1.1875rem); line-height: 1.65; color: var(--t2); }
:lang(ar) .lib-lead { line-height: 1.9; }
.lib-count { margin-block-start: var(--sp-4); font-size: .9375rem; color: var(--t3); font-variant-numeric: tabular-nums; }
.lib-hero .btn { margin-block-start: var(--sp-4); }

/* ---------- Body, tabs, panels ---------- */
.lib-body { padding-block: var(--sp-6) var(--sp-8); }
.lib-tabs {
  display: flex; gap: 4px; margin-block-end: var(--sp-5);
  padding: 4px; border: 1px solid var(--b1); border-radius: 999px; background: var(--s1);
  width: max-content; max-width: 100%; overflow-x: auto;
}
.lib-tabs [role="tab"] {
  display: inline-flex; align-items: center; gap: 8px;
  min-height: 44px; padding: 0 16px; border: 0; border-radius: 999px;
  background: transparent; color: var(--t2); font: inherit; font-size: .9375rem; font-weight: 600; cursor: pointer; white-space: nowrap;
}
.lib-tabs [role="tab"] .i { width: 18px; height: 18px; }
.lib-tabs [role="tab"]:hover { color: var(--t1); }
.lib-tabs [role="tab"][aria-selected="true"] { background: var(--acc-fill); color: var(--on-acc); }
.lib-panel + .lib-panel { margin-block-start: var(--sp-8); }
.js .lib-panel + .lib-panel { margin-block-start: 0; }
.lib-panel-h { font-size: var(--fs-h2); line-height: 1.15; margin-block-end: var(--sp-4); }
.js .lib-panel-h { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.lib-panel-intro { margin-block-end: var(--sp-5); font-size: 1.0625rem; color: var(--t2); }
.lib-panel:focus-visible { outline: 2px solid var(--acc); outline-offset: 6px; border-radius: var(--r-sm); }

/* ---------- Legend, focus line, filter ---------- */
.lib-legend { display: flex; flex-wrap: wrap; align-items: center; gap: var(--sp-2) var(--sp-5); margin-block-end: var(--sp-4); font-size: .875rem; color: var(--t2); }
.lib-legend-h { font-weight: 600; color: var(--t1); }
.lib-legend ul { display: flex; flex-wrap: wrap; gap: var(--sp-2) var(--sp-4); }
.lib-legend li { display: inline-flex; align-items: center; gap: 8px; }
.lib-legend-note { flex-basis: 100%; color: var(--t3); }
.lib-focus {
  min-height: 3.2em; margin-block-end: var(--sp-4); padding: var(--sp-3) var(--sp-4);
  border: 1px dashed var(--b2); border-radius: var(--r-md); font-size: .9375rem; color: var(--t3);
}
.lib-focus strong { color: var(--t1); }
.lib-focus .lib-code { margin-inline-end: 8px; }
.lib-filter {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--sp-3);
  margin-block-end: var(--sp-4); padding: var(--sp-3) var(--sp-4);
  border: 1px solid var(--acc-line); border-radius: var(--r-md); background: var(--acc-soft); color: var(--t1); font-weight: 600;
}

/* ---------- The map: nested list (no JS, and the accordion below 1024px) ---------- */
.lib-tree, .lib-children { list-style: none; margin: 0; padding: 0; }
.lib-children { margin-inline-start: 11px; padding-inline-start: var(--sp-4); border-inline-start: 1px solid var(--b1); }
.lib-row {
  position: relative;
  display: grid; grid-template-columns: auto minmax(0, 1fr) auto; align-items: center; column-gap: 8px;
  padding-block: 2px;
}
.lib-row > .lib-toggle { grid-column: 1; }
.lib-row > .lib-link, .lib-row > .lib-shelf-h, .lib-row > .lib-root-h { grid-column: 2; min-width: 0; }
.lib-row > .lib-dot { grid-column: 3; }
.lib-row > .lib-desc, .lib-row > .lib-rule { grid-column: 2 / 4; }
.lib-shelf-h, .lib-root-h { font-size: inherit; margin: 0; }
.lib-link {
  display: flex; flex-wrap: wrap; align-items: baseline; column-gap: 10px;
  min-height: 44px; padding-block: 10px; color: var(--t1); font-weight: 600; line-height: 1.35;
}
.lib-link .lib-code { flex: none; }
.lib-link .lib-title { min-width: 0; overflow-wrap: break-word; hyphens: manual; }
.lib-link:hover .lib-title { color: var(--acc); }
.lib-desc { margin-block-end: 6px; font-size: .875rem; line-height: 1.55; color: var(--t3); }
:lang(ar) .lib-desc { font-size: .9375rem; line-height: 1.75; }
.lib-rule { margin-block: 4px var(--sp-3); padding: var(--sp-3); border-radius: var(--r-sm); background: var(--s2); font-size: .875rem; line-height: 1.6; color: var(--t2); }
.lib-rule strong { color: var(--t1); }
.lib-node[data-depth="0"] > .lib-row .lib-link { font-size: 1.25rem; }
.lib-node[data-type="shelf"] { margin-block-start: var(--sp-3); }
.lib-node[data-type="shelf"] > .lib-row .lib-link { font-size: 1.125rem; }
.lib-node[data-type="shelf"] { scroll-margin-block-start: calc(var(--header-h) + 16px); }
.lib-node { scroll-margin-block-start: calc(var(--header-h) + 16px); }

.lib-toggle {
  display: inline-grid; place-items: center; flex: none;
  width: 44px; height: 44px; margin-inline-start: -10px; padding: 0;
  border: 0; border-radius: var(--r-sm); background: transparent; color: var(--t3); cursor: pointer;
}
.lib-toggle:hover { color: var(--t1); background: var(--s2); }
.lib-toggle .i { width: 18px; height: 18px; transition: transform var(--d1) var(--ease); }
[dir="rtl"] .lib-toggle .i { transform: scaleX(-1); }
.lib-toggle[aria-expanded="true"] .i { transform: rotate(90deg); }
[dir="rtl"] .lib-toggle[aria-expanded="true"] .i { transform: scaleX(-1) rotate(90deg); }
.lib-toggle-spacer { display: inline-block; width: 34px; }

/* focus / hover relations and question/path highlights */
.lib-tree.is-hl .lib-row { opacity: .45; transition: opacity var(--d1) var(--ease); }
.lib-tree.is-hl .is-cur > .lib-row, .lib-tree.is-hl .is-rel > .lib-row, .lib-tree.is-hl .is-ans > .lib-row { opacity: 1; }
.lib-node.is-cur > .lib-row .lib-title { color: var(--acc); }
.lib-node.is-rel > .lib-row .lib-link .lib-title { text-decoration: underline; text-decoration-color: var(--acc-line); text-underline-offset: 4px; }
.lib-node.is-ans > .lib-row { background: var(--acc-soft); border-radius: var(--r-sm); box-shadow: inset 3px 0 0 var(--acc); }
[dir="rtl"] .lib-node.is-ans > .lib-row { box-shadow: inset -3px 0 0 var(--acc); }

/* ---------- The map: horizontal tree (JS, >= 1024px) ---------- */
.lib-tree.is-tree { --cy: 23px; --gap: 32px; padding-block: var(--sp-2); }
.is-tree .lib-node { display: flex; align-items: flex-start; }
.is-tree .lib-node[data-type="shelf"] { margin-block-start: 0; }
.is-tree .lib-row {
  flex: none; width: var(--w, 240px);
  grid-template-columns: auto minmax(0, 1fr) auto;
  padding: 0 10px; border: 1px solid var(--b1); border-radius: var(--r-md); background: var(--s1);
}
.is-tree .lib-node[data-depth="0"] > .lib-row { --w: 170px; }
.is-tree .lib-node[data-depth="1"] > .lib-row { --w: 200px; }
.is-tree .lib-node[data-depth="2"] > .lib-row { --w: 250px; }
.is-tree .lib-node[data-depth="3"] > .lib-row { flex: 1 1 auto; width: auto; min-width: 220px; max-width: 440px; }
.is-tree .lib-node[data-depth="0"] > .lib-row .lib-link { font-size: 1rem; }
.is-tree .lib-node[data-type="shelf"] > .lib-row .lib-link { font-size: 1rem; }
.is-tree .lib-link { padding-block: 8px; min-height: 44px; font-size: .875rem; }
.is-tree .lib-toggle { width: 32px; height: 44px; margin-inline-start: -6px; }
.is-tree .lib-toggle-spacer { width: 0; }
.is-tree .lib-row > .lib-desc { display: none; }
.is-tree .lib-node[data-type="shelf"] > .lib-row > .lib-desc { display: block; font-size: .8125rem; }
.is-tree .lib-rule { font-size: .8125rem; }
.is-tree .lib-node.is-cur > .lib-row { border-color: var(--acc); }
.is-tree .lib-node.is-rel > .lib-row { border-color: var(--acc-line); }
.is-tree .lib-node.is-ans > .lib-row { border-color: var(--acc); box-shadow: none; }
.is-tree .lib-children {
  position: relative; display: flex; flex-direction: column; gap: 8px;
  margin: 0; padding-inline-start: var(--gap); border: 0; flex: 1 1 auto; min-width: 0;
}
.is-tree .lib-children > .lib-node { position: relative; }
.is-tree .lib-children > .lib-node::before {
  content: ""; position: absolute; inset-inline-start: calc(var(--gap) / -2); inset-block-start: var(--cy);
  width: calc(var(--gap) / 2); border-block-start: 1px solid var(--b2);
}
.is-tree .lib-children > .lib-node::after {
  content: ""; position: absolute; inset-inline-start: calc(var(--gap) / -2); inset-block: 0 -8px;
  border-inline-start: 1px solid var(--b2);
}
.is-tree .lib-children > .lib-node:first-child::after { inset-block-start: var(--cy); }
.is-tree .lib-children > .lib-node:last-child::after { inset-block-end: auto; block-size: var(--cy); }
.is-tree .lib-children > .lib-node:only-child::after { display: none; }
.is-tree .lib-node.is-open > .lib-row::after {
  content: ""; position: absolute; inset-inline-end: calc(var(--gap) / -2 - 1px); inset-block-start: var(--cy);
  width: calc(var(--gap) / 2); border-block-start: 1px solid var(--b2);
}

/* ---------- Questions and reading paths ---------- */
.lib-qs, .lib-paths { display: grid; gap: var(--sp-4); }
.lib-q, .lib-path { padding: var(--sp-5); }
.lib-q h3, .lib-path h3 { font-size: 1.1875rem; line-height: 1.35; }
.lib-q-sub { margin-block: var(--sp-3) var(--sp-2); font-size: .8125rem; font-weight: 600; color: var(--t3); letter-spacing: .04em; text-transform: uppercase; }
:lang(ar) .lib-q-sub { letter-spacing: 0; text-transform: none; font-size: .875rem; }
.lib-answers { display: grid; gap: 0; }
.lib-answers a, .lib-chaps a {
  display: flex; flex-wrap: wrap; align-items: baseline; column-gap: 10px;
  min-height: 44px; padding-block: 10px; color: var(--t1); border-block-start: 1px solid var(--b1);
}
.lib-answers a:hover span, .lib-chaps a:hover { color: var(--acc); }
.lib-q .btn, .lib-path .btn { margin-block-start: var(--sp-3); }
.btn .i { flex: none; }
.lib-steps { display: grid; gap: var(--sp-4); margin-block-start: var(--sp-3); }
.lib-step-h { display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between; gap: 4px var(--sp-3); font-weight: 600; }
.lib-step-h a { display: inline-flex; flex-wrap: wrap; align-items: baseline; gap: 4px 10px; min-height: 44px; padding-block: 10px; color: var(--t1); }
.lib-step-h a:hover span { color: var(--acc); }
.lib-min { font-size: .875rem; font-weight: 500; color: var(--t3); white-space: nowrap; }
.lib-chaps { padding-inline-start: var(--sp-4); }
.lib-sec { color: var(--t3); font-variant-numeric: tabular-nums; }
.lib-total { margin-block-start: var(--sp-4); font-size: .9375rem; color: var(--t2); }
@media (min-width: 900px) {
  .lib-qs { grid-template-columns: repeat(2, 1fr); }
  .lib-paths { grid-template-columns: repeat(3, 1fr); }
}

/* ---------- End CTA ---------- */
.lib-cta { padding-block: var(--sp-7); border-block-start: 1px solid var(--b1); background: var(--s1); }
.lib-cta .container { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--sp-4); }
.lib-cta p { font-size: 1.1875rem; font-weight: 600; color: var(--t1); }

/* ---------- Lab pages ---------- */
.lib-prose > * { max-width: 820px; }
.lib-prose > h2 { margin-block: var(--sp-6) var(--sp-3); font-size: 1.375rem; line-height: 1.3; scroll-margin-block-start: calc(var(--header-h) + 16px); }
.lib-prose > h2:first-child { margin-block-start: 0; }
.lib-prose > p { font-size: 1.0625rem; line-height: 1.7; color: var(--t2); }
:lang(ar) .lib-prose > p { line-height: 1.95; }
.lib-prose > p + p { margin-block-start: var(--sp-3); }
.lib-prose strong { color: var(--t1); }
.lib-prose > .lib-ol { list-style: decimal; padding-inline-start: 1.6em; display: grid; gap: var(--sp-2); margin-block-start: var(--sp-3); font-size: 1.0625rem; line-height: 1.7; color: var(--t2); }
:lang(ar) .lib-prose > .lib-ol { line-height: 1.95; }
.lib-prose > .lib-ol li::marker { color: var(--t3); }
.lib-url { color: var(--acc); overflow-wrap: anywhere; text-decoration: underline; text-underline-offset: 3px; }
.lib-log { display: grid; gap: 0; }
.lib-log-entry { padding-block: var(--sp-5); border-block-start: 1px solid var(--b1); scroll-margin-block-start: calc(var(--header-h) + 16px); }
.lib-log-entry:first-child { border-block-start: 0; padding-block-start: 0; }
.lib-log-h { margin: 0 0 4px; font-size: 1.0625rem; font-weight: 600; line-height: 1.4; }
.lib-log-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 8px var(--sp-3); font-size: .875rem; color: var(--t3); }
.lib-log-meta a { display: inline-flex; align-items: center; min-height: 32px; }
.lib-kind { display: inline-flex; align-items: center; min-height: 24px; padding: 1px 10px; border-radius: 999px; border: 1px solid var(--b2); font-size: .75rem; font-weight: 600; color: var(--t2); }
.lib-kind[data-kind="release"] { color: var(--acc); border-color: var(--acc-line); background: var(--acc-soft); }
.lib-kind[data-kind="correction"] { color: var(--t1); border-color: var(--amber); background: var(--amber-soft); }
.lib-log-sum { margin-block-start: var(--sp-2); font-size: 1.0625rem; line-height: 1.65; color: var(--t1); }
.lib-corr { display: grid; gap: 4px var(--sp-4); margin-block-start: var(--sp-3); font-size: .9375rem; }
.lib-corr dt { font-weight: 600; color: var(--t3); }
.lib-corr dd { color: var(--t2); }
.lib-note { margin-block-start: var(--sp-5); }
.lib-note a { color: var(--acc); text-decoration: underline; text-underline-offset: 3px; display: inline-flex; min-height: 44px; align-items: center; }
.lib-oqs { display: grid; gap: var(--sp-4); }
.lib-oq { padding: var(--sp-5); scroll-margin-block-start: calc(var(--header-h) + 16px); }
.lib-oq h2 { font-size: 1.1875rem; line-height: 1.4; margin-block: 4px var(--sp-3); }
.lib-oq dl { display: grid; gap: 4px; }
.lib-oq dt { margin-block-start: var(--sp-2); font-size: .8125rem; font-weight: 600; color: var(--t3); }
:lang(ar) .lib-oq dt { font-size: .875rem; }
.lib-oq dd { color: var(--t2); line-height: 1.65; }
.lib-oq-st { display: inline-flex; min-height: 24px; align-items: center; padding: 1px 10px; border-radius: 999px; font-size: .75rem; font-weight: 600; color: var(--t1); border: 1px dashed var(--amber); background: var(--amber-soft); }
.lib-oq-st[data-status="settled"] { color: var(--acc); border: 1px solid var(--acc-line); background: var(--acc-soft); }
.lib-labnav { margin-block-start: var(--sp-7); padding-block-start: var(--sp-5); border-block-start: 1px solid var(--b1); }
.lib-labnav-h { font-size: .8125rem; font-weight: 600; color: var(--t3); margin-block-end: var(--sp-2); }
.lib-labnav ul { display: flex; flex-wrap: wrap; gap: 0 var(--sp-5); margin-block-end: var(--sp-4); }
.lib-labnav li a { display: inline-flex; align-items: center; min-height: 44px; color: var(--t1); font-weight: 600; }
.lib-labnav li a[aria-current="page"] { color: var(--acc); }
.lib-labnav .link-cta { min-height: 44px; }
.lib-labnav .link-cta .flip { transform: none; }
[dir="rtl"] .lib-labnav .link-cta .i { transform: scaleX(-1); }

@media (prefers-reduced-motion: reduce) {
  .lib-toggle .i, .lib-tree.is-hl .lib-row { transition: none; }
}
@media print {
  .lib-tabs, .lib-focus, .lib-filter, .lib-toggle, .lib-cta .btn { display: none !important; }
  .lib-panel[hidden], .lib-children[hidden] { display: block !important; }
}

/* ---------- Privacy and measurement policy (/privacy/, /ar/privacy/): privacy_build.py ---------- */
.priv-updated { margin-block-start: var(--sp-3); font-size: .875rem; color: var(--t3); }
.priv-sec { max-width: 820px; }
.priv-sec + .priv-sec { margin-block-start: var(--sp-6); }
.priv-sec h2 { margin-block: 0 var(--sp-3); font-size: 1.375rem; line-height: 1.3; scroll-margin-block-start: calc(var(--header-h) + 16px); }
.priv-sec p, .priv-sec li { font-size: 1.0625rem; line-height: 1.7; color: var(--t2); }
:lang(ar) .priv-sec p, :lang(ar) .priv-sec li { line-height: 1.95; }
.priv-sec p + p, .priv-sec p + .priv-table-wrap, .priv-sec p + ul { margin-block-start: var(--sp-3); }
.priv-sec a { color: var(--acc); text-decoration: underline; text-underline-offset: 3px; }
.priv-list { list-style: disc; padding-inline-start: 1.4em; display: grid; gap: var(--sp-3); }
.priv-table-wrap { overflow-x: auto; border: 1px solid var(--b1); border-radius: var(--r-md); }
.priv-table { width: 100%; border-collapse: collapse; font-size: .9375rem; }
.priv-table th, .priv-table td { padding: 10px 14px; text-align: start; vertical-align: top; border-block-end: 1px solid var(--b1); line-height: 1.6; color: var(--t2); }
.priv-table thead th { background: var(--s1); color: var(--t1); font-weight: 600; }
.priv-table tbody th { white-space: nowrap; font-weight: 500; }
.priv-table tbody tr:last-child th, .priv-table tbody tr:last-child td { border-block-end: 0; }
.priv-ev { font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace; font-size: .875rem; color: var(--t1); direction: ltr; unicode-bidi: isolate; }
@media (max-width: 560px) { .priv-table tbody th { white-space: normal; overflow-wrap: anywhere; } }