/* =============================================================
   UX Meas — shared visual system
   Monochromatic. Typography-led. Mono-inflected.
   ============================================================= */

@import url('https://fonts.googleapis.com/css2?family=Inter+Tight:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ---------- tokens (light) ---------- */
:root {
  /* grayscale, warm-tinted, very low chroma. contrast-tuned for WCAG AA. */
  --bg:        oklch(98.6% 0.003 60);
  --bg-2:      oklch(96.0% 0.003 60);
  --rule:      oklch(88.5% 0.004 60);
  --rule-soft: oklch(92.5% 0.004 60);
  /* placeholder: stays neutral grey in BOTH modes. used for card visual blocks
     so they read as empty image slots, not as blue-tinted surfaces. */
  --placeholder-bg:     oklch(92.5% 0.004 60);
  --placeholder-border: oklch(88.5% 0.004 60);
  --fg:        oklch(18.0% 0.006 60);   /* 14:1 on bg */
  --fg-2:      oklch(38.0% 0.005 60);   /* 6:1 on bg */
  --fg-3:      oklch(48.0% 0.005 60);   /* 4.5:1 on bg */
  --fg-4:      oklch(58.0% 0.005 60);   /* 3:1 on bg, UI-only */
  /* scroll-lit resting color: muted base from which words fade to --accent.
     light: neutral grey (fg-3). dark: cool blue-grey (per CEO spec). */
  --scroll-lit-resting: var(--fg-3);

  /* accent — dual mode. langchain cyan on dark, darker blue on light for contrast.
     used for structural moments: section labels, HMW rules, focus, hover borders,
     lit-state text. same semantic token, adapts per theme. */
  --accent:      #1e6fb8;                /* light mode: 4.9:1 on cream */
  --accent-soft: color-mix(in oklab, var(--accent) 22%, transparent);

  --f-sans: "Inter Tight", ui-sans-serif, system-ui, -apple-system, Helvetica, Arial, sans-serif;
  --f-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --max: 1440px;
  --gutter: clamp(20px, 4vw, 48px);

  /* typography scale — reusable font-size tokens */
  --t-eyebrow: 11px;
  --t-body:    16px;
  --t-lede:    19px;
  --t-h-display: clamp(36px, 5.8vw, 72px); /* hero H1 + case study H1 (consistent) */
  --t-h-section: clamp(26px, 3.6vw, 44px); /* section-level H2 */
  --t-h-sub:     clamp(22px, 2.8vw, 34px); /* sub-display, preview headings */
  --t-stat-n:    clamp(34px, 4.5vw, 52px); /* big stat number (hero hstat-n + about-stats stat-n) */
  --t-mono-label: 11px;                    /* small mono uppercase label (hstat-l etc.) */
  --ls-mono:     0.06em;                   /* mono label letter-spacing */

  --radius: 0px;

  --focus: 0 0 0 2px var(--bg), 0 0 0 4px var(--accent);
}

/* ---------- tokens (dark via system) ---------- */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg:        oklch(13.5% 0.004 60);
    --bg-2:      oklch(17.5% 0.004 60);
    /* dark-mode lines: deep navy, subtle against near-black bg (CEO spec). */
    --rule:      #181f33;
    --rule-soft: #141829;
    /* placeholder stays neutral grey in dark — image slots don't inherit
       the navy line tint. */
    --placeholder-bg:     oklch(26.0% 0.004 60);
    --placeholder-border: oklch(34.0% 0.004 60);
    --fg:        oklch(96.0% 0.003 60);
    --fg-2:      oklch(78.0% 0.004 60);
    --fg-3:      oklch(62.0% 0.004 60);
    --fg-4:      oklch(55.0% 0.004 60);
    /* scroll-lit resting color in dark: cool blue-grey (CEO spec) */
    --scroll-lit-resting: #6a7d9e;
    --accent:    #7fc8ff;
    --accent-soft: color-mix(in oklab, var(--accent) 18%, transparent);
  }
}

/* ---------- explicit overrides via toggle ---------- */
:root[data-theme="dark"] {
  --bg:        oklch(13.5% 0.004 60);
  --bg-2:      oklch(17.5% 0.004 60);
  --rule:      #181f33;
  --rule-soft: #141829;
  --placeholder-bg:     oklch(26.0% 0.004 60);
  --placeholder-border: oklch(34.0% 0.004 60);
  --fg:        oklch(96.0% 0.003 60);
  --fg-2:      oklch(78.0% 0.004 60);
  --fg-3:      oklch(62.0% 0.004 60);
  --fg-4:      oklch(55.0% 0.004 60);
  --scroll-lit-resting: #6a7d9e;
  --accent:    #7fc8ff;
  --accent-soft: color-mix(in oklab, var(--accent) 18%, transparent);
}
:root[data-theme="light"] {
  --bg:        oklch(98.6% 0.003 60);
  --bg-2:      oklch(96.0% 0.003 60);
  --rule:      oklch(88.5% 0.004 60);
  --rule-soft: oklch(92.5% 0.004 60);
  --placeholder-bg:     oklch(92.5% 0.004 60);
  --placeholder-border: oklch(88.5% 0.004 60);
  --fg:        oklch(18.0% 0.006 60);
  --fg-2:      oklch(38.0% 0.005 60);
  --fg-3:      oklch(48.0% 0.005 60);
  --fg-4:      oklch(58.0% 0.005 60);
  --accent:    #1e6fb8;
  --accent-soft: color-mix(in oklab, var(--accent) 22%, transparent);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--f-sans);
  font-size: var(--t-body);
  line-height: 1.55;
  font-feature-settings: "ss01", "cv11";
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }

/* tabular numbers everywhere numbers matter */
.mono, .stat-n, .row-n, .row-meta, .eyebrow, .tags, nav a, .kbd {
  font-family: var(--f-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum", "zero";
}

/* ---------- skip link ---------- */
.skip {
  position: absolute; left: 12px; top: 12px;
  transform: translateY(-200%);
  background: var(--fg); color: var(--bg);
  padding: 8px 12px; font-family: var(--f-mono); font-size: 12px;
  z-index: 100;
}
.skip:focus { transform: translateY(0); outline: none; }

/* ---------- focus ---------- */
a:focus-visible, button:focus-visible {
  outline: none;
  box-shadow: var(--focus);
  border-radius: 2px;
}

/* ---------- layout ---------- */
.wrap {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding-inline: var(--gutter);
}

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in oklab, var(--bg) 88%, transparent);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--rule-soft);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 60px;
}
.wordmark {
  display: inline-flex; align-items: center;
  color: var(--fg);        /* foreground default for .logo-word (wordmark) */
  text-decoration: none;
  line-height: 1;
  flex-shrink: 0;          /* prevent the global svg{max-width:100%} from crushing the mark in tight nav containers */
}
/* Two-tone brand: icon (blue) + wordmark (foreground). Inline SVG paths are split into
   <g class="logo-mark"> + <g class="logo-word"> so each receives its own fill. */
.wordmark .logo-mark { fill: var(--accent); }
.wordmark .logo-word { fill: currentColor; }
.wordmark__svg {
  height: 22px;
  width: 97px;             /* matches inline SVG (viewBox 607.5x128, scaled to 22px tall) */
  display: block;
  flex-shrink: 0;
}
.wordmark__mark {
  display: none;           /* desktop: full mark+wordtype shows, icon-only is hidden */
}
@media (max-width: 600px) {
  .wordmark__svg { display: none; }       /* hide full logo on mobile */
  .wordmark__mark {
    display: block;
    width: 60px;            /* viewBox 273.1x128 scaled to 28px tall */
    height: 28px;
    flex-shrink: 0;
  }
}
/* Legacy .wordmark .dot rule removed — replaced by inline logo SVG (commit replacing 'UX/MEAS' text wordmark with new uxmeas mark + wordtype). */
.nav-links {
  display: flex; align-items: center; gap: 28px;
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--fg-2);
}
.nav-links a { position: relative; padding: 4px 0; }
.nav-links a:hover { color: var(--fg); }
.nav-links .back {
  display: inline-flex; align-items: center; gap: 8px;
}

/* Theme toggle hidden 2026-05-04 — light mode disabled until transparent PNG screens ship.
   Restore by removing `display: none` once case-study assets render cleanly on cream bg. */
.theme-toggle {
  display: none !important;
  appearance: none;
  background: transparent; border: 1px solid var(--rule);
  width: 28px; height: 28px; display: inline-grid; place-items: center;
  color: var(--fg-2); cursor: pointer;
  font-family: var(--f-mono); font-size: 11px;
  transition: color .2s, border-color .2s;
}
.theme-toggle:hover { color: var(--fg); border-color: var(--fg-3); }
.theme-toggle svg { width: 14px; height: 14px; }
.theme-toggle .sun { display: none; }
:root[data-theme="dark"] .theme-toggle .sun,
:root:not([data-theme="light"]) .theme-toggle .sun { display: block; }
:root[data-theme="dark"] .theme-toggle .moon,
:root:not([data-theme="light"]) .theme-toggle .moon { display: none; }
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) .theme-toggle .sun { display: none; }
  :root:not([data-theme="dark"]) .theme-toggle .moon { display: block; }
}

/* ---------- type scale ---------- */
.eyebrow {
  font-size: var(--t-eyebrow);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--fg-3);
  display: inline-flex; align-items: center; gap: 10px;
}
.eyebrow .sep { color: var(--fg-4); }

h1, h2, h3, h4 {
  font-family: var(--f-sans);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.02;
  margin: 0;
  color: var(--fg);
}

.h-display {
  font-size: var(--t-h-display);
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1.0;
}
.h-case {
  /* case study H1: uses same scale as hero H1 for consistency */
  font-size: var(--t-h-display);
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1.0;
}
.h-section {
  font-size: var(--t-h-section);
  font-weight: 500;
  letter-spacing: -0.022em;
  line-height: 1.08;
  color: var(--fg-3);
}

/* Scroll-lit text effect (LangChain-style). JS splits into .word spans,
   toggles .lit based on scroll position so words fade to accent as viewed.
   Resting color is --scroll-lit-resting (grey on light, blue-grey on dark). */
.h-section.scroll-lit .word {
  color: var(--scroll-lit-resting);
  transition: color .35s ease-out, text-shadow .35s ease-out;
  display: inline-block;
}
.h-section.scroll-lit .word.lit {
  color: var(--accent);
}
.h-section.scroll-lit .word.just-lit {
  text-shadow: 0 0 20px var(--accent-soft);
}
@media (prefers-reduced-motion: reduce) {
  .h-section.scroll-lit .word { transition: none; }
  .h-section.scroll-lit .word.just-lit { text-shadow: none; }
}
.lede {
  font-size: var(--t-lede);
  line-height: 1.5;
  color: var(--fg-2);
  max-width: 58ch;
  text-wrap: pretty;
}
p { text-wrap: pretty; }

/* ---------- rules ---------- */
.rule { border: 0; height: 1px; background: var(--rule); margin: 0; }
.rule-soft { border: 0; height: 1px; background: var(--rule-soft); margin: 0; }

/* ---------- stats row ---------- */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}
.stats.three { grid-template-columns: repeat(3, 1fr); }
.stat {
  padding: 28px 24px 24px;
  border-left: 1px solid var(--rule-soft);
  min-height: 140px;
  display: flex; flex-direction: column; justify-content: space-between;
}
.stat:first-child { border-left: 0; }
.stat-n {
  font-family: var(--f-sans);
  font-size: clamp(32px, 4.2vw, 52px);
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--fg);
}
.stat-l {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--fg-3);
  margin-top: 20px;
}
@media (max-width: 768px) {
  .stats, .stats.three { grid-template-columns: repeat(2, 1fr); }
  .stat { border-left: 1px solid var(--rule-soft); padding: 22px 18px 18px; min-height: 120px; }
  .stat:first-child, .stat:nth-child(3) { border-left: 0; }
  .stat:nth-child(3), .stat:nth-child(4) { border-top: 1px solid var(--rule-soft); }
  .stats.three .stat:nth-child(3) { grid-column: 1 / -1; border-left: 0; }
  .stat-n { font-size: 36px; }
}

/* ---------- buttons ---------- */
.btn-row { display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 12px 18px;
  font-family: var(--f-mono); font-size: 12px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border: 1px solid var(--fg);
  color: var(--fg);
  background: transparent;
  transition: background .15s, color .15s;
}
.btn-primary { background: var(--fg); color: var(--bg); }
.btn-primary:hover { background: transparent; color: var(--fg); }
.btn-secondary:hover { background: var(--fg); color: var(--bg); }
.btn .arrow { transition: transform .2s; }
.btn:hover .arrow { transform: translateX(3px); }

/* ---------- breadcrumbs (case-study pages) ---------- */
.breadcrumbs {
  border-bottom: 1px solid var(--rule);
  padding: 18px 0;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--fg-3);
}
.breadcrumbs .wrap {
  display: flex;
  align-items: center;
  gap: 10px;
}
.breadcrumbs a {
  color: var(--fg-3);
  transition: color .15s;
}
.breadcrumbs a:hover { color: var(--accent); }
.breadcrumbs .sep {
  color: var(--fg-4);
}
.breadcrumbs [aria-current="page"] {
  color: var(--fg);
}

/* ---------- section-num badge — icon + ( N ) + Name on ONE row ---------- */
.badge.section-num {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.badge.section-num .sn-icon,
.badge.section-num svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  color: var(--accent);
}
.badge.section-num .sn-text {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
}
.badge.section-num .sn-num {
  color: var(--fg-3);
  font-weight: 400;
}
.badge.section-num .sn-name {
  color: var(--fg);
  font-weight: 500;
}

/* ---------- section header ---------- */
.section {
  padding: clamp(72px, 10vw, 140px) 0;
  border-top: 1px solid var(--rule);
}
.section-head {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 48px;
  align-items: baseline;
  margin-bottom: 56px;
}
.section-head .label {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--accent);
  letter-spacing: 0.04em;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.section-head .label svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  stroke: var(--accent);
  stroke-width: 2;
}
@media (max-width: 768px) {
  .section-head { grid-template-columns: 1fr; gap: 20px; margin-bottom: 36px; }
}

/* ---------- footer ---------- */
footer.site {
  padding: 40px 0 60px;
  border-top: 1px solid var(--rule);
  color: var(--fg-3);
  font-family: var(--f-mono);
  font-size: 12px;
}
footer.site .site-footer-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  flex-wrap: wrap;
  gap: 12px;
}
footer.site a:hover { color: var(--accent); }

/* ---------- case study: next-cta inner layout ---------- */
.next-cta .next-cta-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 32px;
  align-items: end;
  width: 100%;
}
@media (max-width: 700px) {
  .next-cta .next-cta-row { grid-template-columns: 1fr; align-items: start; }
}

/* ---------- prose paragraph spacing utility (case study reflection) ---------- */
.reflection .col p + p { margin-top: 16px; }

/* ---------- scroll reveal (adopted from current dev site) ----------
   Subtle slide-up on section enter via translateY 20px→0.
   JS (scroll-reveal.js) toggles .visible on IntersectionObserver.
   IMPORTANT (fix 2026-05-06): opacity defaults to 1, not 0. The reveal
   animation is now slide-only — if scroll-reveal.js fails for any reason
   (timing race, observer threshold, browser quirk), content is still
   rendered. Previously opacity:0 caused entire sections to disappear when
   the observer didn't fire reliably. */
.reveal {
  opacity: 1;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .reveal { opacity: 1; transform: none; }
}

/* ---------- selection ---------- */
::selection { background: var(--accent-soft); color: var(--fg); }

/* =============================================================
   Hero shader — Simplex-noise WebGL field behind hero content
   Sits absolute behind .wrap, masked at the edges so the noise
   never competes with the headline. Falls back to nothing if
   WebGL is unavailable.
   ============================================================= */
.hero { position: relative; isolation: isolate; }
.hero > .wrap { position: relative; z-index: 1; }

.hero-shader {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  display: block;
  pointer-events: none;          /* clicks pass through to content */
  opacity: 0.85;
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 45%, #000 30%, transparent 85%);
          mask-image: radial-gradient(ellipse 80% 70% at 50% 45%, #000 30%, transparent 85%);
}
.hero-shader.webgl-disabled { display: none; }

@media (prefers-reduced-motion: reduce) {
  .hero-shader { opacity: 0.55; }       /* static frame, lower presence */
}

/* Hero stats sit above the shader — soften the hairlines so they
   don't compete with the noise field behind. Theme-adaptive: faint
   white on dark, faint dark on light. */
.hero .hstat                    { border-top-color: color-mix(in oklab, var(--fg) 10%, transparent); }
@media (max-width: 900px) {
  .hero .hstat                  { border-top-color: color-mix(in oklab, var(--fg) 10%, transparent);
                                  border-left-color: color-mix(in oklab, var(--fg) 10%, transparent); }
}