/* Quantitative Intelligence Studio — site styles
   Plain CSS, no build step. Colours and type are tokens on :root. */

:root {
  --bg: #f6f5f1;
  --surface: #ffffff;
  --ink: #15202b;
  --ink-2: #44505c;
  --ink-3: #6b7681;
  --rule: #dcdad3;
  --rule-strong: #c4c1b8;
  --accent: #1f3a5f;
  --accent-soft: #e6ebf1;
  --signal: #3d6b5c;
  --wip: #8a5a12;
  --wip-soft: #f6ecda;

  --serif: "Iowan Old Style", "Charter", "Source Serif Pro", Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --max: 1120px;
  --gutter: clamp(16px, 4vw, 40px);
  --section: clamp(72px, 10vw, 128px);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1419;
    --surface: #161d24;
    --ink: #e7e9ea;
    --ink-2: #b3bac1;
    --ink-3: #87909a;
    --rule: #26303a;
    --rule-strong: #34404b;
    --accent: #9db6d6;
    --accent-soft: #1b2733;
    --signal: #86b8a6;
    --wip: #e0b76f;
    --wip-soft: #2b2416;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 var(--sans);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}
img, svg { max-width: 100%; display: block; }
a { color: var(--accent); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }

.skip { position: absolute; left: -9999px; }
.skip:focus { left: 16px; top: 12px; background: var(--surface); padding: 8px 12px; z-index: 10; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--rule);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 24px; height: 64px; }
.brand { display: flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none; }
.brand-mark { width: 28px; height: 28px; flex: none; }
.brand-name { font-family: var(--serif); font-size: 17px; letter-spacing: .01em; line-height: 1.2; }
.nav { display: flex; gap: 28px; }
.nav a { color: var(--ink-2); text-decoration: none; font-size: 14px; letter-spacing: .02em; }
.nav a:hover { color: var(--ink); }

@media (max-width: 760px) {
  .nav { display: none; }
  .brand-name { font-size: 16px; }
}

/* ---------- Type ---------- */
.eyebrow {
  font: 600 12px/1 var(--sans);
  letter-spacing: .14em; text-transform: uppercase;
  color: var(--ink-3); margin: 0 0 20px;
  display: flex; align-items: center; gap: 12px;
}
.eyebrow::before { content: ""; width: 24px; height: 1px; background: var(--rule-strong); }
h1, h2, h3 { font-family: var(--serif); font-weight: 400; color: var(--ink); margin: 0; text-wrap: balance; }
h1 { font-size: clamp(34px, 4.4vw, 54px); line-height: 1.08; letter-spacing: -.01em; }
h2 { font-size: clamp(28px, 3.6vw, 40px); line-height: 1.15; letter-spacing: -.005em; }
h3 { font-size: 21px; line-height: 1.3; }
p { margin: 0 0 1em; }
.lede { font-size: clamp(18px, 2vw, 21px); line-height: 1.6; color: var(--ink-2); max-width: 62ch; }
.muted { color: var(--ink-3); }
.small { font-size: 14px; }

/* ---------- Sections ---------- */
section { padding: var(--section) 0; border-top: 1px solid var(--rule); }
section:first-of-type { border-top: 0; }
.section-head { display: grid; grid-template-columns: 1fr; gap: 16px; margin-bottom: 48px; max-width: 760px; }

/* ---------- Hero ---------- */
.hero { padding-top: clamp(56px, 9vw, 112px); padding-bottom: clamp(56px, 8vw, 96px); }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); gap: clamp(32px, 6vw, 80px); align-items: center; }
.hero h1 { margin-bottom: 28px; }
.hero .descriptor { font: 500 15px/1.4 var(--sans); letter-spacing: .04em; color: var(--accent); margin: 0 0 24px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 36px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 20px; border-radius: 2px;
  font: 500 15px/1 var(--sans); text-decoration: none;
  border: 1px solid var(--accent);
}
.btn-primary { background: var(--accent); color: var(--bg); }
.btn-primary:hover { opacity: .9; }
.btn-ghost { color: var(--accent); background: transparent; }
.btn-ghost:hover { background: var(--accent-soft); }

.figure {
  background: var(--surface);
  border: 1px solid var(--rule);
  padding: 20px 20px 14px;
}
.figure figcaption { font-size: 12px; color: var(--ink-3); margin-top: 10px; letter-spacing: .02em; }
.chart text { font: 11px var(--sans); fill: var(--ink-3); }
.chart .axis { stroke: var(--rule-strong); stroke-width: 1; }
.chart .grid { stroke: var(--rule); stroke-width: 1; }
.chart .curve { fill: none; stroke: var(--accent); stroke-width: 2; }
.chart .pt { fill: var(--ink-3); opacity: .45; }
.chart .pt-key { fill: var(--signal); }

@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; }
}

/* ---------- About ---------- */
.about-grid { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr); gap: clamp(32px, 6vw, 80px); }
.about-grid .body p { color: var(--ink-2); max-width: 64ch; }
.facts { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--ink); }
.facts li { display: grid; grid-template-columns: 120px 1fr; gap: 16px; padding: 16px 0; border-bottom: 1px solid var(--rule); font-size: 15px; }
.facts .k { color: var(--ink-3); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; padding-top: 3px; }
.principles { margin-top: 40px; display: grid; gap: 0; border-top: 1px solid var(--rule); }
.principles div { display: grid; grid-template-columns: 48px 1fr; padding: 18px 0; border-bottom: 1px solid var(--rule); }
.principles .n { font: 13px var(--mono); color: var(--ink-3); padding-top: 3px; }
.principles strong { font-weight: 600; color: var(--ink); }
.principles p { margin: 0; }

@media (max-width: 860px) {
  .about-grid { grid-template-columns: 1fr; }
  .facts li { grid-template-columns: 100px 1fr; }
}

/* ---------- Contact ---------- */
.contact-grid { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr); gap: clamp(32px, 6vw, 80px); align-items: start; }
.contact-list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--ink); }
.contact-list li { display: grid; grid-template-columns: 110px 1fr; gap: 16px; padding: 16px 0; border-bottom: 1px solid var(--rule); }
.contact-list .k { color: var(--ink-3); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; padding-top: 4px; }
.contact-list a { overflow-wrap: anywhere; }
.placeholder { background: var(--wip-soft); color: var(--wip); padding: 1px 6px; border-radius: 2px; font-size: .92em; }

@media (max-width: 860px) {
  .contact-grid { grid-template-columns: 1fr; }
}

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--rule); padding: 40px 0 56px; font-size: 13px; color: var(--ink-3); }
.site-footer .wrap { display: grid; gap: 12px; }
.site-footer p { margin: 0; max-width: 90ch; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

/* ---------- Hero capability stack ---------- */
.stack { border: 1px solid var(--rule); background: var(--surface); padding: 20px 20px 8px; position: relative; }
.stack-title { font: 600 12px/1 var(--sans); letter-spacing: .12em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 14px; }
.stack ol { list-style: none; margin: 0; padding: 0 0 0 16px; border-left: 2px solid var(--accent); }
.stack li + li { border-top: 1px solid var(--rule); }
.stack a { display: grid; grid-template-columns: 32px 1fr; gap: 8px; padding: 11px 6px; color: var(--ink); text-decoration: none; }
.stack a:hover { background: var(--accent-soft); }
.stack .n { font: 12px var(--mono); color: var(--ink-3); padding-top: 3px; }
.stack strong { display: block; font-weight: 600; font-size: 15px; line-height: 1.3; }
.stack em { display: block; font-style: normal; color: var(--ink-3); font-size: 13.5px; line-height: 1.4; }

/* ---------- Approach (USP) ---------- */
.usp-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 1px; background: var(--rule); border: 1px solid var(--rule); }
.usp-grid article { background: var(--surface); padding: 24px 22px 26px; display: flex; flex-direction: column; gap: 10px; }
.usp-grid .n { font: 12px var(--mono); color: var(--ink-3); }
.usp-grid h3 { font-size: 19px; }
.usp-grid p { margin: 0; color: var(--ink-2); font-size: 15px; }
.usp-grid .proof { margin-top: auto; padding-top: 12px; border-top: 1px solid var(--rule); color: var(--ink-3); font-size: 13.5px; }
.usp-grid .usp-sum { background: var(--accent); }
.usp-grid .usp-sum h3, .usp-grid .usp-sum p { color: var(--bg); }
@media (max-width: 1000px) { .usp-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 560px) { .usp-grid { grid-template-columns: 1fr; } }

/* ---------- Behavioural lens ---------- */
.behav-grid { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr); gap: clamp(32px, 6vw, 80px); align-items: center; }
.behav-grid h2 { margin-bottom: 20px; }
.chart .bar { fill: var(--accent); opacity: .35; }
.chart .bar-neg { fill: var(--wip); opacity: .7; }
.chart .bar-total { fill: var(--accent); }
.chart .link { stroke: var(--ink-3); stroke-dasharray: 2 3; fill: none; }
.chart .em { fill: var(--wip); }
@media (max-width: 860px) { .behav-grid { grid-template-columns: 1fr; } }

/* ---------- Portfolio ---------- */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 28px; }
.filters button {
  font: 500 13.5px/1 var(--sans); color: var(--ink-2); background: transparent;
  border: 1px solid var(--rule-strong); border-radius: 2px; padding: 9px 12px; cursor: pointer;
}
.filters button:hover { color: var(--ink); border-color: var(--ink-3); }
.filters button[aria-pressed="true"] { background: var(--accent); border-color: var(--accent); color: var(--bg); }
.projects { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.project { background: var(--surface); border: 1px solid var(--rule); padding: clamp(22px, 3vw, 32px); display: flex; flex-direction: column; gap: 12px; }
.project[hidden] { display: none; }
.p-meta { display: flex; justify-content: space-between; gap: 12px; font-size: 12.5px; color: var(--ink-3); letter-spacing: .03em; }
.project h3 { font-size: 22px; }
.status { font: 600 11px/1 var(--sans); letter-spacing: .1em; text-transform: uppercase; padding: 6px 8px; border-radius: 2px; width: fit-content; }
.s-done { color: var(--signal); background: color-mix(in srgb, var(--signal) 12%, transparent); }
.s-wip { color: var(--wip); background: var(--wip-soft); }
.project dl { margin: 4px 0 0; display: grid; grid-template-columns: 76px 1fr; gap: 10px 14px; font-size: 15px; }
.project dt { font: 600 11.5px/1.9 var(--sans); letter-spacing: .1em; text-transform: uppercase; color: var(--ink-3); }
.project dd { margin: 0; color: var(--ink-2); }
.project dd ul { margin: 6px 0; padding-left: 18px; }
.project dd li { margin: 3px 0; }
.chips { list-style: none; margin: auto 0 0; padding: 14px 0 0; border-top: 1px solid var(--rule); display: flex; flex-wrap: wrap; gap: 6px; }
.chips li { font-size: 12px; color: var(--accent); background: var(--accent-soft); padding: 4px 8px; border-radius: 2px; }
@media (max-width: 860px) { .projects { grid-template-columns: 1fr; } }
@media (max-width: 480px) { .project dl { grid-template-columns: 1fr; gap: 2px; } .project dd { margin-bottom: 10px; } }

/* ---------- Services grid & engagement steps ---------- */
.usp-grid.cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.usp-grid.cols-3 p { font-size: 15.5px; }
@media (max-width: 1000px) { .usp-grid.cols-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 560px) { .usp-grid.cols-3 { grid-template-columns: 1fr; } }
.steps-head { margin: 64px 0 20px; }
.steps { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border-top: 2px solid var(--accent); }
.steps li { padding: 20px 24px 0 0; display: flex; flex-direction: column; gap: 6px; }
.steps .n { font: 12px var(--mono); color: var(--ink-3); }
.steps strong { font-family: var(--serif); font-weight: 400; font-size: 21px; color: var(--ink); }
.steps p { margin: 0; color: var(--ink-2); font-size: 15px; }
@media (max-width: 860px) { .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); row-gap: 8px; } }
@media (max-width: 480px) { .steps { grid-template-columns: 1fr; } }

/* ---------- Product ---------- */
.product-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: clamp(32px, 6vw, 80px); align-items: center; }
.product-name { font-size: clamp(34px, 4.4vw, 52px); margin: 16px 0 16px; }
.product-points { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--ink); }
.product-points li { padding: 18px 0; border-bottom: 1px solid var(--rule); color: var(--ink-2); font-size: 15.5px; }
.product-points strong { color: var(--ink); font-weight: 600; }
@media (max-width: 860px) { .product-grid { grid-template-columns: 1fr; } }