/* ------------------------------------------------------------------
   abtests.co.uk — design tokens
   The whole site is a split test. Variant A leads with test blue,
   variant B leads with control orange. Everything else stays put.
------------------------------------------------------------------- */
:root {
  --ink: #141b2e;
  --paper: #f4f6f9;
  --card: #ffffff;
  --muted: #5b6474;
  --line: #dde2ea;
  --accent: #2450f0;
  --accent-2: #ff6b2c;
  --accent-soft: #e6ebfd;
  --radius: 10px;
  --display: "Instrument Serif", Georgia, serif;
  --body: "Instrument Sans", -apple-system, "Segoe UI", sans-serif;
  --mono: "Spline Sans Mono", "SF Mono", Menlo, monospace;
}
html[data-variant="B"] {
  --accent: #ff6b2c;
  --accent-2: #2450f0;
  --accent-soft: #ffe9de;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  margin: 0;
  font-family: var(--body);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
.wrap-narrow { max-width: 720px; margin: 0 auto; padding: 0 24px; }

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--ink); }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 3px; }

h1, h2, h3 { font-family: var(--display); font-weight: 400; line-height: 1.12; margin: 0 0 0.5em; letter-spacing: -0.005em; }

.eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 14px;
}

/* ---------------- header ---------------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.header-inner { display: flex; align-items: center; gap: 28px; height: 64px; }
.wordmark {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--mono); font-size: 1rem; font-weight: 500;
  color: var(--ink); text-decoration: none;
}
.wordmark em { font-style: normal; color: var(--muted); }
.wordmark .mark { width: 22px; height: 22px; }

.site-nav { display: flex; gap: 20px; margin-left: auto; align-items: center; }
.site-nav a { font-size: 0.92rem; font-weight: 500; color: var(--ink); text-decoration: none; }
.site-nav a:hover { color: var(--accent); }
.nav-cta {
  background: var(--ink); color: #fff !important; padding: 8px 16px;
  border-radius: 999px;
}
.nav-cta:hover { background: var(--accent); }

/* the signature: variant toggle */
.variant-toggle {
  display: flex; align-items: center; gap: 8px;
  font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.06em;
  color: var(--muted); background: none; border: 1px solid var(--line);
  border-radius: 999px; padding: 5px 6px 5px 12px; cursor: pointer;
}
.vt-pill { display: inline-flex; border-radius: 999px; overflow: hidden; border: 1px solid var(--line); }
.vt-pill span { padding: 2px 9px; font-weight: 500; }
html[data-variant="A"] .vt-a, html[data-variant="B"] .vt-b { background: var(--accent); color: #fff; }
.variant-toggle:hover { border-color: var(--accent); color: var(--ink); }

/* ---------------- hero ---------------- */
.hero { padding: 84px 0 64px; border-bottom: 1px solid var(--line); }
.hero-grid { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 56px; align-items: center; }
.hero h1 { font-size: clamp(2.4rem, 5.2vw, 4rem); margin-bottom: 20px; }
.hero h1 .flip { color: var(--accent); font-style: italic; }
.hero-sub { font-size: 1.15rem; color: var(--muted); max-width: 34em; margin: 0 0 30px; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-block; font-weight: 600; font-size: 0.95rem;
  padding: 12px 22px; border-radius: 999px; text-decoration: none;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--ink); color: #fff; }
.btn-ghost { border: 1px solid var(--line); color: var(--ink); background: var(--card); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }
.hero-note { margin-top: 18px; font-family: var(--mono); font-size: 0.72rem; color: var(--muted); }

.hero-viz { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; }
.hero-viz svg { display: block; width: 100%; height: auto; }

/* ---------------- sections ---------------- */
.section { padding: 72px 0; }
.section + .section { border-top: 1px solid var(--line); }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 20px; margin-bottom: 36px; }
.section-head h2 { font-size: clamp(1.7rem, 3vw, 2.3rem); margin: 0; }
.section-head a { font-family: var(--mono); font-size: 0.78rem; letter-spacing: 0.08em; text-transform: uppercase; }

.cards-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px; display: flex; flex-direction: column; gap: 10px;
}
.card h3 { font-size: 1.35rem; margin: 0; }
.card p { margin: 0; color: var(--muted); font-size: 0.98rem; }
.card .eyebrow { margin: 0; }

/* blog cards */
.post-card { text-decoration: none; color: var(--ink); transition: transform 0.15s ease, border-color 0.15s ease; overflow: hidden; padding: 0; }
.post-card:hover { transform: translateY(-3px); border-color: var(--accent); color: var(--ink); }
.post-card img { width: 100%; height: auto; display: block; border-bottom: 1px solid var(--line); background: var(--paper); }
.post-card-body { padding: 20px 22px 24px; display: flex; flex-direction: column; gap: 8px; }
.post-card h3 { font-size: 1.3rem; }
.post-card time { font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); }
.post-card p { color: var(--muted); font-size: 0.95rem; margin: 0; }

.blog-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }

/* ---------------- posts ---------------- */
.post-header { padding: 72px 0 36px; text-align: left; }
.post-title { font-size: clamp(2.1rem, 4.5vw, 3.2rem); }
.post-standfirst { font-size: 1.2rem; color: var(--muted); margin: 0; }
.post-hero { margin: 0 auto 12px; max-width: 920px; }
.post-hero img { width: 100%; height: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--card); }
.post-body { padding: 28px 24px 24px; }
.post-body h2 { font-size: 1.75rem; margin-top: 1.6em; }
.post-body h3 { font-size: 1.3rem; margin-top: 1.4em; }
.post-body blockquote {
  margin: 1.6em 0; padding: 4px 0 4px 22px; border-left: 3px solid var(--accent);
  font-family: var(--display); font-size: 1.25rem; font-style: italic; color: var(--ink);
}
.post-body code { font-family: var(--mono); font-size: 0.88em; background: var(--accent-soft); padding: 1px 5px; border-radius: 4px; }
.post-body hr { border: 0; border-top: 1px solid var(--line); margin: 2.4em 0; }
.post-cta {
  margin: 40px auto; padding: 30px; background: var(--ink); color: #fff;
  border-radius: var(--radius);
}
.post-cta h2 { color: #fff; font-size: 1.6rem; }
.post-cta p { margin: 0; color: #c8cede; }
.post-cta a { color: #fff; }
.post-more { padding-bottom: 72px; }
.post-more ul { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 8px; }

/* ---------------- graveyard ---------------- */
.grave {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px; margin-bottom: 18px;
}
.grave-head { display: flex; justify-content: space-between; gap: 16px; align-items: baseline; flex-wrap: wrap; }
.grave h3 { font-size: 1.4rem; margin: 0 0 6px; }
.grave .verdict {
  font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase;
  padding: 4px 10px; border-radius: 999px; white-space: nowrap;
}
.verdict-lost { background: #ffe4dc; color: #b3391c; }
.verdict-flat { background: #eceff4; color: var(--muted); }
.verdict-won-then-faded { background: #fff3d6; color: #8a6410; }
.grave dl { display: grid; grid-template-columns: 120px 1fr; gap: 6px 18px; margin: 14px 0 0; }
.grave dt { font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); padding-top: 3px; }
.grave dd { margin: 0; font-size: 0.98rem; }
.grave .lesson { border-top: 1px dashed var(--line); margin-top: 16px; padding-top: 14px; font-size: 0.98rem; }
.grave .lesson strong { color: var(--accent); }

/* ---------------- simulator ---------------- */
.sim-panel { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; }
.sim-controls { display: flex; gap: 24px; flex-wrap: wrap; margin-bottom: 22px; }
.sim-controls label { display: flex; flex-direction: column; gap: 6px; font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); }
.sim-controls input, .sim-controls select {
  font-family: var(--body); font-size: 1rem; padding: 9px 12px;
  border: 1px solid var(--line); border-radius: 8px; background: var(--paper); color: var(--ink); min-width: 130px;
}
.sim-results { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 22px; }
.sim-stat { background: var(--paper); border: 1px solid var(--line); border-radius: 8px; padding: 16px; }
.sim-stat b { display: block; font-family: var(--display); font-size: 2rem; line-height: 1.1; }
.sim-stat.bad b { color: #b3391c; }
.sim-stat span { font-size: 0.85rem; color: var(--muted); }
#simChart { width: 100%; height: auto; display: block; margin-top: 10px; }

/* ---------------- footer ---------------- */
.site-footer { border-top: 1px solid var(--line); background: var(--card); margin-top: 48px; }
.footer-inner { padding: 44px 24px; display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 28px; }
.footer-brand { font-family: var(--mono); font-weight: 500; margin: 0 0 8px; }
.footer-brand em { font-style: normal; color: var(--muted); }
.footer-note { color: var(--muted); font-size: 0.92rem; margin: 0; max-width: 34em; }
.footer-nav { display: flex; flex-direction: column; gap: 6px; align-items: flex-start; }
.footer-nav a { color: var(--muted); font-size: 0.92rem; text-decoration: none; }
.footer-nav a:hover { color: var(--accent); }
.footer-meta { grid-column: 1 / -1; font-family: var(--mono); font-size: 0.72rem; color: var(--muted); border-top: 1px solid var(--line); padding-top: 18px; margin: 6px 0 0; }

/* ---------------- forms / contact ---------------- */
.contact-form { display: grid; gap: 16px; max-width: 560px; }
.contact-form label { display: grid; gap: 6px; font-weight: 600; font-size: 0.92rem; }
.contact-form input, .contact-form textarea {
  font-family: var(--body); font-size: 1rem; padding: 11px 14px;
  border: 1px solid var(--line); border-radius: 8px; background: var(--card);
}

/* ---------------- responsive ---------------- */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; }
  .cards-3, .blog-grid, .sim-results { grid-template-columns: 1fr 1fr; }
  .site-nav { display: none; }
}
@media (max-width: 620px) {
  .cards-3, .blog-grid, .sim-results { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
  .hero { padding: 56px 0 44px; }
  .variant-toggle .vt-label { display: none; }
}