/* Technology chronicle: a tree behind the page, a vertical timeline and a reading panel.
   Colors follow the site's black/white surfaces; the four layer hues are the
   validated categorical slots 1–4, ordered so adjacent layers stay distinct. */

.page-technology-tree {
  --ch-gutter: 3rem;
  --ch-physical: #3987e5; --ch-software: #d95926; --ch-knowledge: #199e70; --ch-people: #c98500;
}
:root[data-theme="light"] .page-technology-tree {
  --ch-physical: #2a78d6; --ch-software: #eb6834; --ch-knowledge: #1baf7a; --ch-people: #eda100;
}
.page-technology-tree [data-layer="physical"] { --layer: var(--ch-physical); }
.page-technology-tree [data-layer="software"] { --layer: var(--ch-software); }
.page-technology-tree [data-layer="knowledge"] { --layer: var(--ch-knowledge); }
.page-technology-tree [data-layer="people"] { --layer: var(--ch-people); }

/* Page frame */
.page-technology-tree .sky { display: none; }
.page-technology-tree .shell { display: block; max-width: 1240px; padding: 0 var(--ch-gutter); }
.page-technology-tree .shell > .side, .page-technology-tree .rail, .page-technology-tree .mobile-toc, .page-technology-tree .chapter-context { display: none; }
.page-technology-tree .shell > .side.open { display: block; }
.page-technology-tree .prose { max-width: none; }
.page-technology-tree main { padding-top: 1rem; }
.page-technology-tree .article-head { margin: 2.6rem 0 0; padding: 0; border: 0; }
.page-technology-tree .article-head::before, .page-technology-tree .article-head .note-tools,
.page-technology-tree .article-head .prep-note, .page-technology-tree .article-kicker,
.page-technology-tree .article-meta, .page-technology-tree .article-save { display: none; }
.page-technology-tree .article-head h1 { max-width: none; margin: 0; font-size: clamp(2.4rem, 5vw, 3.8rem); font-weight: 500; letter-spacing: -.045em; line-height: 1.1; }
.prose .tree-intro { max-width: 44rem; margin: 1rem 0 0; }
.prose .tree-lead { margin: 0; color: var(--muted); font-size: 1.08rem; line-height: 1.75; }

/* The tree: a fixed canvas behind the page that grows on entry, then steps back. */
.ch-tree { position: fixed; inset: 0; z-index: 0; width: 100vw; height: 100vh; pointer-events: none; transition: opacity .2s linear; }
.page-technology-tree .shell { position: relative; z-index: 1; }
:root:not([data-theme="light"]) .page-technology-tree .article-head h1, :root:not([data-theme="light"]) .prose .tree-lead { text-shadow: 0 2px 24px rgba(0,0,0,.65); }
.ch-stage { position: relative; height: calc(100svh - 22rem); min-height: 14rem; }
.prose .ch-year { position: absolute; left: 0; bottom: 3.2rem; margin: 0; color: #fff4dc; font: 200 clamp(2.6rem, 6vw, 4.6rem)/1 var(--sans); letter-spacing: -.045em;
  font-variant-numeric: tabular-nums; text-shadow: 0 0 34px rgba(255,190,110,.45); transition: font-size .6s ease, color .6s ease, opacity .6s ease; }
:root[data-theme="light"] .prose .ch-year { color: #8a5a1a; text-shadow: none; }
.prose .ch-year.is-done { color: var(--muted); font-size: 1rem; font-weight: 500; letter-spacing: .02em; text-shadow: none; }
.prose .ch-hint { position: absolute; left: 0; bottom: 1.4rem; margin: 0; color: var(--muted); font-size: .82rem; }
.prose .ch-jump { margin-left: .9rem; color: #e9a23b; text-decoration: none; border-bottom: 1px solid color-mix(in srgb, #e9a23b 40%, transparent); }
.prose .ch-jump:hover { border-bottom-color: #e9a23b; }

/* Field filter: pinned right under the 52px top bar, on an opaque strip. */
.ch-bar { position: sticky; top: 52px; z-index: 5; margin: 0 calc(-1 * var(--ch-gutter)); padding: .8rem var(--ch-gutter); background: var(--paper);
  border-bottom: 1px solid var(--rule); }
.ch-fields { display: flex; flex-wrap: wrap; gap: .45rem; }
.ch-field { display: inline-flex; flex: none; align-items: center; gap: .45rem; padding: .42rem .8rem; border: 1px solid var(--rule); border-radius: 999px; background: none;
  color: var(--ink-soft); font: 500 .8rem/1 var(--body); cursor: pointer; transition: border-color .15s ease, background-color .15s ease, color .15s ease; }
.ch-field i { width: .5rem; height: .5rem; border-radius: 50%; background: var(--layer); }
.ch-field small { color: var(--muted); font: 500 .7rem/1 var(--mono); }
.ch-field:not(:disabled):hover { border-color: color-mix(in srgb, var(--ink) 40%, transparent); color: var(--ink); }
.ch-field[aria-pressed="true"] { border-color: var(--ink); background: var(--ink); color: var(--paper); }
.ch-field[aria-pressed="true"] small { color: inherit; opacity: .7; }
/* timeline / star map switch (chronicle-starmap.js) */
.ch-bar:has(.ch-views:not([hidden])) { display: flex; align-items: flex-start; gap: 1rem; }
.ch-bar .ch-fields { flex: 1; min-width: 0; }
.ch-views { display: inline-flex; flex: none; padding: 3px; border: 1px solid var(--rule); border-radius: 999px; }
.ch-views[hidden] { display: none; }
.ch-views button { padding: .36rem .85rem; border: 0; border-radius: 999px; background: none; color: var(--muted); font: 600 .78rem/1 var(--sans); cursor: pointer; }
.ch-views button[aria-pressed="true"] { background: var(--ink); color: var(--paper); }
.ch-starmap { position: relative; margin: 1.2rem 0 2rem; }
.ch-starmap[hidden] { display: none; }
.ch-starmap canvas { display: block; width: 100%; height: min(72vh, 680px); cursor: grab; touch-action: none; border-radius: 18px;
  background: radial-gradient(ellipse at 50% 52%, color-mix(in srgb, var(--paper) 70%, #000) 0%, var(--paper) 75%); border: 1px solid var(--rule); }
/* while the star map is open the tree behind the page steps back */
body:has(.technology-chronicle.is-starmap) .ch-tree { opacity: .12 !important; }
.ch-starmap canvas:active { cursor: grabbing; }
.prose .ch-starmap-hint { margin: .6rem 0 0; color: var(--muted); font-size: .8rem; text-align: center; }
.ch-field:disabled { cursor: default; }
.ch-field:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }

/* The timeline: periods from top to bottom, milestones on a spine. */
.ch-periods { padding: 1rem 0 2rem; }
.ch-era { display: grid; grid-template-columns: minmax(12rem, 19rem) minmax(0, 1fr); gap: 3rem; padding: 2.6rem 0 1.4rem; scroll-margin-top: 7.5rem; }
.ch-era + .ch-era { border-top: 1px solid var(--rule); }
.ch-era[hidden] { display: none; }
.ch-era-head { align-self: start; position: sticky; top: 8.5rem; }
.prose .ch-era-years { margin: 0; color: var(--muted); font: 600 .78rem/1 var(--mono); letter-spacing: .04em; }
.ch-era-live { margin-left: .7rem; padding: .15rem .5rem; border: 1px solid color-mix(in srgb, #e9a23b 45%, transparent); border-radius: 999px; color: #e9a23b; font: 600 .7rem/1 var(--sans); letter-spacing: 0; vertical-align: .1em; }
.prose .ch-era-head h2 { margin: .65rem 0 0; padding: 0; border: 0; font-size: clamp(1.35rem, 2.1vw, 1.7rem); font-weight: 600; letter-spacing: -.025em; line-height: 1.3; }
.prose .ch-era-head h2::before { display: none; }
.prose .ch-era-summary { margin: .85rem 0 0; color: var(--muted); font-size: .9rem; line-height: 1.85; }
.prose .ch-spine { position: relative; margin: 0; padding: 0 0 0 1.6rem; list-style: none; }
.ch-spine::before { content: ""; position: absolute; left: .32rem; top: .4rem; bottom: .4rem; width: 1px; background: linear-gradient(var(--rule), var(--rule) 85%, transparent); }
.prose .ch-spine li { position: relative; margin: 0 0 .55rem; padding: 0; }
.ch-spine li[hidden] { display: none; }
.ch-spine li::before { content: ""; position: absolute; left: calc(-1.6rem + .32rem - 4px); top: 1.15rem; width: 9px; height: 9px; border-radius: 50%; background: var(--paper);
  box-shadow: inset 0 0 0 2px var(--layer, var(--ink)); }
.ch-spine li[data-key]::before { background: var(--layer); box-shadow: 0 0 0 3px color-mix(in srgb, var(--layer) 22%, transparent), 0 0 12px color-mix(in srgb, var(--layer) 60%, transparent); }
.prose .ch-item { display: block; padding: .8rem 1rem .85rem; border-radius: 14px; color: var(--ink); text-decoration: none; border-bottom: 0;
  background: color-mix(in srgb, var(--paper) 90%, transparent);  /* no backdrop blur: a hundred blurred cards over the animated tree made scrolling stutter */
  box-shadow: inset 0 0 0 1px var(--rule); transition: box-shadow .15s ease, transform .15s ease, background-color .15s ease; }
.prose .ch-item:hover, .prose .ch-item:focus-visible { box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--layer) 70%, transparent), 0 10px 26px -18px rgba(0,0,0,.6); transform: translateX(2px); outline: none; }
.prose .ch-item.is-current { box-shadow: inset 0 0 0 1.5px var(--layer); background: color-mix(in srgb, var(--layer) 10%, var(--paper)); }
.ch-item-top { display: flex; align-items: baseline; gap: .7rem; }
.ch-item time { flex: none; color: var(--muted); font: 600 .76rem/1.4 var(--mono); }
.ch-item-name { font-size: .98rem; font-weight: 640; line-height: 1.4; letter-spacing: -.005em; }
.ch-item-hook { display: block; margin-top: .25rem; padding-left: 3.05rem; color: var(--muted); font-size: .85rem; line-height: 1.6; }
/* the 3D object beside each card (chronicle-artifacts.js); the space is kept only once the script runs */
.ch-art { position: absolute; right: .7rem; top: 50%; width: 64px; height: 64px; margin-top: -32px; cursor: grab; touch-action: none; }
.ch-art:active { cursor: grabbing; }
.ch-art[hidden] { display: none; }
.ch-art-ready .prose .ch-item, .prose .ch-art-ready .ch-item { padding-right: 5.6rem; }
.ch-more { display: inline-flex; align-items: center; gap: .4rem; margin: .4rem 0 0 1.6rem; padding: .48rem .9rem; border: 1px solid var(--rule); border-radius: 999px; background: none;
  color: var(--ink-soft); font: 500 .8rem/1 var(--body); cursor: pointer; }
.ch-more::after { content: "↓"; font-family: var(--mono); }
.ch-more[aria-expanded="true"]::after { content: "↑"; }
.ch-more:hover { color: var(--ink); border-color: color-mix(in srgb, var(--ink) 40%, transparent); }
.ch-more[hidden] { display: none; }
.prose .ch-empty { margin: 1rem 0 0; color: var(--muted); font-size: .88rem; }

/* Every milestone in full. Without JavaScript they follow the periods; with it they open in the panel. */
.ch-library { display: grid; gap: 1.2rem; margin: 4rem 0 0; }
.technology-chronicle.is-enhanced .ch-library { display: none; }
.chronicle-work { padding: 1.5rem 1.6rem; border: 1px solid var(--rule); border-radius: 18px; scroll-margin-top: 7rem; }
.ch-era { scroll-margin-top: 6rem; }
.ch-panel .chronicle-work { padding: 0; border: 0; border-radius: 0; }
.prose .ch-work-meta, .ch-work-meta { display: flex; flex-wrap: wrap; gap: .35rem .9rem; margin: 0 0 .85rem; color: var(--muted); font: 500 .74rem/1.4 var(--mono); }
.ch-topic i { display: inline-block; width: .5rem; height: .5rem; margin-right: .4rem; border-radius: 50%; background: var(--layer); vertical-align: .02em; }
.ch-unsettled { color: #e9a23b; }
.chronicle-work h3 { margin: 0; padding: 0; border: 0; font-size: 1.6rem; font-weight: 620; letter-spacing: -.025em; line-height: 1.28; }
.chronicle-work h3::before { display: none; }
.chronicle-work h3:focus { outline: none; }
.ch-sub { display: block; margin-top: .4rem; color: var(--muted); font-size: 1rem; font-weight: 450; letter-spacing: 0; }
.chronicle-lead { margin: 1.1rem 0 0; font-size: 1.02rem; line-height: 1.95; }
.ch-links { display: flex; flex-wrap: wrap; gap: .55rem 1rem; margin: 1.1rem 0 0; font-size: .8rem; }
.ch-link-group { display: inline-flex; flex-wrap: wrap; align-items: center; gap: .35rem; }
.ch-link-type { margin-right: .1rem; color: var(--muted); }
.prose .ch-links a { padding: .22rem .6rem; border: 1px solid var(--rule); border-radius: 999px; color: var(--ink); text-decoration: none; }
.ch-links a:hover { border-color: color-mix(in srgb, var(--ink) 40%, transparent); }
.chronicle-more, .chronicle-references { margin: 1.1rem 0 0; padding: .8rem 0 0; border-top: 1px solid var(--rule); }
.chronicle-more summary, .chronicle-references summary { display: flex; align-items: center; gap: .5rem; color: var(--ink-soft); font: 600 .84rem/1.4 var(--body); list-style: none; cursor: pointer; }
.chronicle-more summary::-webkit-details-marker, .chronicle-references summary::-webkit-details-marker { display: none; }
.chronicle-more summary::after, .chronicle-references summary::after { content: "+"; margin-left: auto; color: var(--muted); font: 400 1rem/1 var(--mono); }
.chronicle-more[open] summary::after, .chronicle-references[open] summary::after { content: "−"; }
.chronicle-source-count { color: var(--muted); font: 500 .74rem var(--mono); }
.chronicle-explanation { margin: .8rem 0 0; color: var(--ink-soft); font-size: .94rem; line-height: 1.9; }
.prose .ch-fold-label, .ch-fold-label { margin: 1.1rem 0 .3rem; color: var(--muted); font: 600 .72rem/1 var(--body); letter-spacing: .06em; }
.chronicle-limit { margin: 0; font-size: .92rem; line-height: 1.85; }
.chronicle-connections { margin: 1rem 0 0; padding: 0; list-style: none; font-size: .84rem; }
.chronicle-connections li { margin: .55rem 0 0; }
.chronicle-connections p { margin: .15rem 0 0; color: var(--muted); line-height: 1.7; }
.chronicle-sources { margin: .6rem 0 0; padding: 0; list-style: none; }
.chronicle-sources li { margin: 0; border-top: 1px solid var(--rule-soft, var(--rule)); }
.chronicle-sources li:first-child { border-top: 0; }
.prose .chronicle-sources a { display: flex; justify-content: space-between; gap: 1rem; padding: .55rem 0; color: var(--ink); font-size: .84rem; line-height: 1.5; text-decoration: none; }
.chronicle-sources a:hover span:first-child { text-decoration: underline; text-underline-offset: .2em; }

/* Reading panel */
.ch-panel { position: fixed; z-index: 85; top: 64px; right: 14px; bottom: 14px; display: flex; flex-direction: column; width: min(480px, calc(100vw - 28px)); color: var(--ink);
  border-radius: 22px; background: color-mix(in srgb, var(--paper) 90%, transparent); -webkit-backdrop-filter: blur(26px) saturate(1.3); backdrop-filter: blur(26px) saturate(1.3);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.06), inset 0 0 0 1px var(--rule), 0 40px 100px -30px rgba(0,0,0,.75); animation: ch-panel-in .3s cubic-bezier(.2,.8,.2,1); }
.ch-panel[hidden] { display: none; }
@keyframes ch-panel-in { from { opacity: 0; transform: translateX(18px); } to { opacity: 1; transform: none; } }
.ch-panel-bar { display: flex; align-items: center; gap: .4rem; padding: .85rem .9rem .5rem 1.1rem; }
.ch-panel-step, .ch-panel-close { width: 32px; height: 32px; border: 0; border-radius: 999px; background: color-mix(in srgb, var(--ink) 7%, transparent); color: var(--ink); font: 400 .95rem/1 var(--body); cursor: pointer; }
.ch-panel-step:hover, .ch-panel-close:hover { background: color-mix(in srgb, var(--ink) 14%, transparent); }
.ch-panel-step:disabled { opacity: .3; cursor: default; }
.ch-panel-count { margin-right: auto; padding-left: .3rem; color: var(--muted); font: 500 .74rem var(--mono); }
.ch-panel-body { flex: 1; overflow-y: auto; padding: .6rem 1.7rem 1.8rem; overscroll-behavior: contain; font-family: var(--body); }
.ch-panel button:focus-visible, .ch-panel a:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }

@media (max-width: 900px) {
  .page-technology-tree { --ch-gutter: 1.5rem; }
  .ch-era { grid-template-columns: minmax(0, 1fr); gap: 1.2rem; padding-top: 2rem; }
  .ch-era-head { position: static; }
}
@media (max-width: 650px) {
  .page-technology-tree { --ch-gutter: 1rem; }
  .page-technology-tree .article-head { margin-top: 1.8rem; }
  .ch-fields { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; }
  .ch-fields::-webkit-scrollbar { display: none; }
  .ch-bar:has(.ch-views:not([hidden])) { flex-direction: column-reverse; gap: .6rem; }
  .ch-starmap canvas { height: 60vh; }
  .ch-item-hook { padding-left: 0; }
  .ch-art { width: 48px; height: 48px; margin-top: -24px; right: .5rem; }
  .prose .ch-art-ready .ch-item { padding-right: 4.2rem; }
  .ch-panel { top: auto; left: 8px; right: 8px; bottom: 8px; width: auto; height: min(82vh, 760px); border-radius: 20px; animation-name: ch-sheet-in; }
  @keyframes ch-sheet-in { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: none; } }
  .ch-panel-body { padding: .4rem 1.2rem 1.4rem; }
  .chronicle-work h3 { font-size: 1.35rem; }
}
@media (prefers-reduced-motion: reduce) {
  .ch-field, .ch-item, .ch-tree, .prose .ch-year { transition: none; }
  .ch-panel { animation: none; }
}
@media print {
  .ch-tree, .ch-bar, .ch-panel, .ch-stage, .ch-more { display: none !important; }
  .technology-chronicle.is-enhanced .ch-library { display: grid; }
  .ch-spine li[hidden], .ch-era[hidden] { display: block !important; }
  .ch-era-head { position: static; }
}