/* ── Essence Way of Working — GitHub Pages stylesheet ─────────────────── */

/* ── CSS custom properties ─────────────────────────────────────────────── */
:root {
  /* A Practice is never itself in an area of concern (Customer/Solution/Endeavor) —
     only Alphas and Activities are, tagged in the RDF. All practices therefore
     share one neutral colour; per-activity colouring is handled separately
     (see DOMAIN_COLOR_CFG in build.py). */
  --neutral: #0f172a;
  --ent:     var(--neutral);
  --sol:     var(--neutral);
  --mva:     var(--neutral);
  --mvg:     var(--neutral);
  --port:    var(--neutral);
  --wf:      var(--neutral);
  --prac:    var(--neutral); /* overridden by data-prac selector below */

  /* Foreground */
  --fg: #0f172a;
}

/* ── Practice colour override ──────────────────────────────────────────── */
[data-prac="neutral"] { --prac: var(--neutral); }

/* ── Base resets ───────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }

html { font-size: 16px; }

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  color: var(--fg);
  margin: 0;
}

/* ── Typography ────────────────────────────────────────────────────────── */
.prose {
  max-width: 72ch;
  line-height: 1.75;
  color: #475569;
  font-size: 0.9375rem;
  margin: 0 0 1rem;
}

h1, h2, h3, h4 {
  font-family: 'Fraunces', Georgia, serif;
}

/* ── Skip link ─────────────────────────────────────────────────────────── */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  z-index: 999;
  border-bottom-right-radius: 0.5rem;
  background: #0f172a;
  padding: 0.625rem 1.125rem;
  font-size: 0.8125rem;
  font-weight: 600;
  color: #fff;
  text-decoration: none;
}
.skip-link:focus-visible { top: 0; }

/* ── Top nav ───────────────────────────────────────────────────────────── */
.topnav {
  position: fixed;
  inset: 0 0 auto;
  z-index: 200;
  background: #fff;
}

/* mobile toggle — hidden by default, shown <900px via Tailwind max-[900px] */
.topnav-toggle {
  display: none;
}

/* ── Topnav dropdown ──────────────────────────────────────────────────── */
.topnav-drop { position: relative; }

.topnav-drop-menu {
  position: absolute;
  left: 0;
  top: calc(100% + 6px);
  z-index: 301;
  min-width: 220px;
  border: 1px solid #e2e8f0;
  border-radius: 0.75rem;
  background: #fff;
  box-shadow: 0 8px 24px rgba(0,0,0,.1);
  padding: 0.375rem;
  list-style: none;
  margin: 0;
}

.topnav-drop-menu li a {
  display: block;
  padding: 0.5rem 0.875rem;
  border-radius: 0.5rem;
  font-size: 0.8125rem;
  color: #334155;
  text-decoration: none;
  transition: background 0.12s;
}

.topnav-drop-menu li a:hover {
  background: #f1f5f9;
  color: #0f172a;
}

.topnav-drop-label {
  display: block;
  padding: 0.375rem 0.875rem 0.125rem;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.5625rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: #94a3b8;
}

.topnav-drop-sep {
  display: block;
  border-top: 1px solid #e2e8f0;
  margin: 0.25rem 0.5rem;
}

/* ── Sidenav ───────────────────────────────────────────────────────────── */
.sidenav {
  position: fixed;
  bottom: 0;
  left: 0;
  top: 100px;  /* 56px logo row + 40px nav-links row */
  z-index: 100;
  width: 240px;
  overflow-y: auto;
  overflow-x: hidden;
  border-right: 1px solid #cbd5e1;
  background: #fff;
  padding-bottom: 1.5rem;
}

/* ── Sidenav nav items (populated by nav.js) ─────────────────────────── */
.snav-section {
  padding: 0.75rem 1rem 0.25rem;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.5625rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: #94a3b8;
}

.snav-link {
  display: block;
  padding: 0.4rem 1rem;
  font-size: 0.8125rem;
  color: #475569;
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color 0.12s, border-color 0.12s;
}

.snav-link:hover,
.snav-link.active {
  color: var(--prac);
  border-left-color: var(--prac);
}

/* ── Page shell ────────────────────────────────────────────────────────── */
.page-shell {
  display: flex;
  min-height: 100vh;
  padding-top: 100px;
}

.page-main {
  margin-left: 240px;
  min-width: 0;
  flex: 1;
}

/* ── Mobile overrides ──────────────────────────────────────────────────── */
@media (max-width: 900px) {
  .topnav-toggle { display: flex; }
  .sidenav { transform: translateX(-100%); transition: transform 0.2s; }
  .sidenav.open { transform: translateX(0); }
  .page-main { margin-left: 0; }
}

/* ── Utility: bar in mobile toggle ─────────────────────────────────────── */
.topnav-toggle .bar {
  display: block;
  width: 16px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  margin: 2px auto;
  transition: transform 0.2s;
}

/* ── Overlay ───────────────────────────────────────────────────────────── */
.sidenav-overlay {
  position: fixed;
  inset: 100px 0 0;
  z-index: 90;
  background: rgba(0,0,0,.25);
}

/* ── Fonts fallback (if Google Fonts unavailable) ──────────────────────── */
@supports not (font-variation-settings: normal) {
  body { font-family: system-ui, sans-serif; }
  h1, h2, h3, h4 { font-family: Georgia, serif; }
}