/* Estate Agent — a standards document that happens to be a website.
   Editorial serif, generous margins, one restrained accent. Light first,
   dark mode honoured. No webfonts: the page must render instantly on a
   corporate laptop behind a proxy. */

:root {
  --paper:      #fdfbf7;
  --paper-2:    #f5f1e9;
  --ink:        #17130f;
  --ink-2:      #443c33;
  --muted:      #756a5d;
  --rule:       #e2dacd;
  --rule-2:     #cfc4b2;
  --accent:     #8a2b1f;
  --accent-2:   #a8412f;
  --link:       #1f3a5f;
  --ok:         #2f6b45;
  --warn:       #8a6420;
  --code-bg:    #f3efe6;

  --serif: 'Iowan Old Style', 'Palatino Linotype', Palatino, 'Book Antiqua',
           Georgia, 'Times New Roman', serif;
  --sans: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --mono: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas,
          'Liberation Mono', monospace;

  --measure: 34rem;
  --wide: 66rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper:    #12100e;
    --paper-2:  #1b1815;
    --ink:      #ece5da;
    --ink-2:    #c8bfb1;
    --muted:    #988d7e;
    --rule:     #2e2823;
    --rule-2:   #443c33;
    --accent:   #e0705c;
    --accent-2: #ef8a75;
    --link:     #8fb6dd;
    --ok:       #7fbf95;
    --warn:     #d5a552;
    --code-bg:  #1c1916;
  }
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.0625rem;
  line-height: 1.65;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

/* ---------------------------------------------------------------- masthead */

.masthead {
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
  position: sticky; top: 0; z-index: 20;
  backdrop-filter: saturate(1.2) blur(6px);
}
.masthead .inner {
  max-width: var(--wide); margin: 0 auto;
  padding: 0.85rem 1.5rem;
  display: flex; align-items: baseline; gap: 1.25rem; flex-wrap: wrap;
}
.wordmark {
  font-family: var(--serif);
  font-size: 1.05rem; font-weight: 600;
  letter-spacing: 0.02em; color: var(--ink);
  text-decoration: none; white-space: nowrap;
}
.wordmark span { color: var(--accent); }
.masthead nav {
  margin-left: auto; display: flex; gap: 1.1rem; flex-wrap: wrap;
  font-family: var(--sans); font-size: 0.78rem;
  text-transform: uppercase; letter-spacing: 0.08em;
}
.masthead nav a { color: var(--muted); text-decoration: none; }
.masthead nav a:hover { color: var(--accent); }

/* ------------------------------------------------------------------ layout */

.wrap { max-width: var(--wide); margin: 0 auto; padding: 0 1.5rem; }
.prose { max-width: var(--measure); }
main { padding: 3rem 0 5rem; }

/* --------------------------------------------------------------- typography */

h1, h2, h3, h4 {
  font-family: var(--serif); font-weight: 600;
  line-height: 1.2; letter-spacing: -0.01em;
  color: var(--ink); margin: 2.75rem 0 0.85rem;
}
h1 { font-size: clamp(2rem, 5vw, 2.9rem); margin-top: 0; letter-spacing: -0.02em; }
h2 { font-size: clamp(1.4rem, 3vw, 1.72rem); padding-top: 1.6rem; border-top: 1px solid var(--rule); }
h3 { font-size: 1.16rem; }
h4 { font-size: 1rem; text-transform: uppercase; letter-spacing: 0.07em;
     font-family: var(--sans); color: var(--muted); }

p { margin: 0 0 1.15rem; }
a { color: var(--link); text-underline-offset: 0.16em; text-decoration-thickness: 1px; }
a:hover { color: var(--accent); }

strong { font-weight: 650; }
em { font-style: italic; }

.anchor {
  margin-left: 0.4rem; color: var(--rule-2); text-decoration: none;
  font-family: var(--sans); font-size: 0.7em; opacity: 0;
  transition: opacity 0.15s;
}
h2:hover .anchor, h3:hover .anchor { opacity: 1; }

ul, ol { margin: 0 0 1.15rem; padding-left: 1.35rem; }
li { margin-bottom: 0.4rem; }
li::marker { color: var(--rule-2); }

blockquote {
  margin: 1.5rem 0; padding: 0.1rem 0 0.1rem 1.15rem;
  border-left: 2px solid var(--accent);
  color: var(--ink-2); font-style: italic;
}
blockquote p:last-child { margin-bottom: 0; }

hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5rem 0; }

code {
  font-family: var(--mono); font-size: 0.855em;
  background: var(--code-bg); padding: 0.1em 0.34em;
  border-radius: 3px; border: 1px solid var(--rule);
  font-style: normal;
}
pre {
  margin: 0; padding: 1rem 1.15rem;
  background: var(--code-bg); border: 1px solid var(--rule);
  border-radius: 4px; line-height: 1.5;
}
pre code { background: none; border: 0; padding: 0; font-size: 0.83rem; }

.scroll { overflow-x: auto; margin: 0 0 1.4rem; max-width: 100%; }

table { border-collapse: collapse; width: 100%; font-size: 0.94rem; }
th, td {
  text-align: left; padding: 0.55rem 0.85rem;
  border-bottom: 1px solid var(--rule); vertical-align: top;
}
th {
  font-family: var(--sans); font-size: 0.73rem; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.07em; color: var(--muted);
  border-bottom: 1px solid var(--rule-2); white-space: nowrap;
}
tbody tr:hover { background: var(--paper-2); }

img { max-width: 100%; height: auto; }

/* -------------------------------------------------------------------- hero */

.hero { padding: 4.5rem 0 1rem; }
.hero .lede {
  font-size: clamp(1.1rem, 2.3vw, 1.32rem);
  color: var(--ink-2); max-width: 38rem; line-height: 1.5;
}
.eyebrow {
  font-family: var(--sans); font-size: 0.72rem; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.16em;
  color: var(--accent); margin: 0 0 1rem;
}
.hero h1 { max-width: 20ch; }
.cta { display: flex; gap: 0.75rem; flex-wrap: wrap; margin-top: 1.9rem; }
.button {
  font-family: var(--sans); font-size: 0.85rem; font-weight: 600;
  letter-spacing: 0.02em; text-decoration: none;
  padding: 0.6rem 1.15rem; border-radius: 3px;
  background: var(--accent); color: #fff; border: 1px solid var(--accent);
}
.button:hover { background: var(--accent-2); color: #fff; }
.button.ghost { background: none; color: var(--ink); border-color: var(--rule-2); }
.button.ghost:hover { border-color: var(--accent); color: var(--accent); }

/* ------------------------------------------------------------ demo (hero) */

.demo {
  margin: 3.5rem 0 1rem; border: 1px solid var(--rule-2);
  border-radius: 5px; background: var(--paper-2); overflow: hidden;
}
.demo-head {
  padding: 0.9rem 1.25rem; border-bottom: 1px solid var(--rule);
  display: flex; gap: 0.9rem; align-items: baseline; flex-wrap: wrap;
  font-family: var(--sans); font-size: 0.78rem; color: var(--muted);
}
.demo-head strong {
  font-family: var(--serif); font-size: 1rem; color: var(--ink);
  font-weight: 600;
}
.demo-body { padding: 1.25rem; }

.chips { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 1.25rem; }
.chip {
  font-family: var(--mono); font-size: 0.78rem;
  padding: 0.35rem 0.7rem; border-radius: 3px; cursor: pointer;
  border: 1px solid var(--rule-2); background: var(--paper);
  color: var(--ink-2); transition: all 0.15s;
}
.chip:hover { border-color: var(--accent); color: var(--accent); }
.chip[aria-pressed="true"] {
  background: var(--accent); border-color: var(--accent); color: #fff;
}

.estate { display: grid; gap: 0.6rem; grid-template-columns: 1fr; }
@media (min-width: 720px) {
  .estate { grid-template-columns: repeat(3, 1fr); gap: 1rem; align-items: start; }
}
.column h4 { margin: 0 0 0.55rem; font-size: 0.68rem; }

.node {
  border: 1px solid var(--rule-2); border-radius: 4px;
  background: var(--paper); padding: 0.6rem 0.75rem; margin-bottom: 0.5rem;
  font-family: var(--sans); font-size: 0.82rem;
  opacity: 0.45; transition: opacity 0.3s, border-color 0.3s,
              background 0.3s, transform 0.3s;
}
.node .name { font-family: var(--mono); font-size: 0.82rem; color: var(--ink); }
.node .meta { display: block; font-size: 0.7rem; color: var(--muted); margin-top: 0.2rem; }
.node.source {
  opacity: 1; border-color: var(--accent); border-width: 2px;
  background: var(--paper);
}
.node.hit {
  opacity: 1; border-color: var(--accent); background: var(--paper);
  transform: translateY(-1px);
}
.node.hit.client { border-color: var(--warn); }
.node.hit .meta { color: var(--accent); }
.node.hit.client .meta { color: var(--warn); }

.order { margin-top: 1.5rem; border-top: 1px solid var(--rule); padding-top: 1.15rem; }
.order h4 { margin: 0 0 0.6rem; }
.order ol { margin: 0; padding-left: 1.3rem; font-size: 0.92rem; }
.order li { margin-bottom: 0.45rem; opacity: 0; transform: translateY(3px);
            transition: opacity 0.35s, transform 0.35s; }
.order li.show { opacity: 1; transform: none; }
.order .muted { color: var(--muted); }

.demo-note {
  font-size: 0.83rem; color: var(--muted); margin: 1rem 0 0;
  font-style: italic;
}

/* ------------------------------------------------------------------ pieces */

.grid {
  display: grid; gap: 1.5rem; margin: 2rem 0;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
}
.card {
  border: 1px solid var(--rule); border-radius: 4px;
  padding: 1.1rem 1.2rem; background: var(--paper-2);
}
.card h3 { margin: 0 0 0.45rem; font-size: 1.02rem; }
.card p { margin: 0; font-size: 0.92rem; color: var(--ink-2); }

.stat { font-family: var(--mono); font-size: 0.9rem; color: var(--ok); }

/* Documentation pages: prose at a readable measure, contents alongside it on
   wide screens rather than stacked above, which otherwise leaves the right
   third of a spec page empty. */
.doc { display: block; }
@media (min-width: 62rem) {
  .doc {
    display: grid;
    grid-template-columns: minmax(0, var(--measure)) 1fr;
    gap: 4rem;
    align-items: start;
  }
  .doc .toc {
    position: sticky; top: 5rem;
    order: 2; margin-top: 0.6rem;
    border-left: 1px solid var(--rule);
    max-height: calc(100vh - 8rem); overflow-y: auto;
  }
  .doc .prose { order: 1; }
}

.toc {
  font-family: var(--sans); font-size: 0.85rem;
  border-left: 2px solid var(--rule); padding-left: 1rem; margin: 0 0 2rem;
}
.toc::before {
  content: "On this page"; display: block;
  font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--rule-2); margin-bottom: 0.55rem;
}
.toc ul { list-style: none; padding: 0; margin: 0; }
.toc li { margin-bottom: 0.3rem; }
.toc a { color: var(--muted); text-decoration: none; }
.toc a:hover { color: var(--accent); }

footer {
  border-top: 1px solid var(--rule); margin-top: 4rem;
  padding: 2rem 0 3rem; font-family: var(--sans);
  font-size: 0.82rem; color: var(--muted);
}
footer a { color: var(--muted); }
footer .row { display: flex; gap: 1.5rem; flex-wrap: wrap; }

.skip {
  position: absolute; left: -9999px;
}
.skip:focus {
  left: 1rem; top: 0.5rem; z-index: 50; background: var(--paper);
  padding: 0.5rem 1rem; border: 1px solid var(--accent);
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

@media print {
  .masthead, .demo, .cta { display: none; }
  body { background: #fff; color: #000; }
}

/* ------------------------------------------------------------- the ladder */

.ladder { list-style: none; padding: 0; margin: 2rem 0 0; counter-reset: none; }

.level {
  border: 1px solid var(--rule); border-radius: 4px;
  margin-bottom: 0.6rem; background: var(--paper);
  transition: border-color 0.2s, background 0.2s;
}
.level.open { border-color: var(--rule-2); background: var(--paper-2); }
.level.here { border-color: var(--accent); border-width: 2px; }
.level.done { opacity: 0.72; }

.level-head {
  display: flex; align-items: center; gap: 1rem; width: 100%;
  padding: 0.9rem 1.1rem; background: none; border: 0; cursor: pointer;
  text-align: left; font-family: var(--serif); color: var(--ink);
  font-size: 1rem;
}
.level-head:hover .level-title strong { color: var(--accent); }

.level-no {
  flex: 0 0 2rem; height: 2rem; border-radius: 50%;
  border: 1px solid var(--rule-2); display: grid; place-items: center;
  font-family: var(--sans); font-size: 0.85rem; font-weight: 600;
  color: var(--muted);
}
.level.open .level-no, .level.here .level-no {
  background: var(--accent); border-color: var(--accent); color: #fff;
}
.level.done .level-no {
  background: var(--ok); border-color: var(--ok); color: #fff;
}

.level-title { display: flex; flex-direction: column; gap: 0.1rem; flex: 1; }
.level-title strong { font-weight: 600; font-size: 1.04rem; }
.level-tag {
  font-family: var(--sans); font-size: 0.8rem; color: var(--muted);
}

.badge {
  font-family: var(--sans); font-size: 0.65rem; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.09em;
  padding: 0.22rem 0.5rem; border-radius: 2px;
  background: var(--accent); color: #fff; white-space: nowrap;
}
.badge.done { background: var(--ok); }

.level-body { padding: 0 1.1rem 1.1rem 4.1rem; }
.level-body p { margin: 0 0 1rem; }
.level-body h4 {
  margin: 1.1rem 0 0.4rem; font-size: 0.68rem; color: var(--muted);
}
.level-body ul { margin: 0 0 0.5rem; padding-left: 1.2rem; font-size: 0.95rem; }
.level-body ul.gap li::marker { color: var(--warn); }

.level-facts {
  margin-top: 1.2rem; padding-top: 0.9rem;
  border-top: 1px solid var(--rule);
  display: grid; gap: 0.7rem;
}
@media (min-width: 46rem) {
  .level-facts { grid-template-columns: 1fr 1fr; gap: 0.9rem 1.5rem; }
}
.level-facts > div { font-size: 0.9rem; }
.level-facts span {
  display: block; font-family: var(--sans); font-size: 0.66rem;
  text-transform: uppercase; letter-spacing: 0.09em; color: var(--muted);
  margin-bottom: 0.15rem;
}

/* ------------------------------------------------------------- self-check */

.quiz {
  margin-top: 2.5rem; padding: 1.4rem 1.5rem;
  border: 1px solid var(--rule-2); border-radius: 4px; background: var(--paper-2);
}
.quiz h3 { margin: 0 0 0.35rem; font-size: 1.12rem; }
.quiz-intro { color: var(--muted); font-size: 0.92rem; margin-bottom: 1.3rem; }

.q {
  display: flex; gap: 1rem; align-items: flex-start;
  justify-content: space-between; flex-wrap: wrap;
  padding: 0.75rem 0; border-top: 1px solid var(--rule);
}
.q.locked { opacity: 0.4; pointer-events: none; }
.q-ask { margin: 0; flex: 1 1 20rem; font-size: 0.96rem; }
.q-hint {
  display: block; font-family: var(--sans); font-size: 0.78rem;
  color: var(--muted); margin-top: 0.2rem;
}
.q-buttons { display: flex; gap: 0.4rem; }
.q-buttons button {
  font-family: var(--sans); font-size: 0.8rem; font-weight: 600;
  padding: 0.35rem 0.85rem; border-radius: 3px; cursor: pointer;
  border: 1px solid var(--rule-2); background: var(--paper); color: var(--ink-2);
}
.q-buttons button:hover { border-color: var(--accent); color: var(--accent); }
.q-buttons button.on {
  background: var(--accent); border-color: var(--accent); color: #fff;
}

.verdict {
  margin-top: 1.4rem; padding-top: 1.2rem; border-top: 2px solid var(--accent);
}
.verdict p { margin: 0 0 0.6rem; }
.verdict .next-title {
  font-weight: 600; font-size: 1.05rem; margin-top: 1rem;
}