:root {
  --ink: #0b1f33;
  --paper: #f4f7f8;
  --white: #ffffff;
  --mint: #6de0ba;
  --gold: #f7bd69;
  --muted: #526474;
  --line: #d6e0e5;
  --shadow: 0 18px 60px rgba(11, 31, 51, .09);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 1rem;
  line-height: 1.6;
}
a { color: inherit; }
button { font: inherit; }
.skip-link { position: fixed; left: 1rem; top: -5rem; z-index: 10; background: var(--white); padding: .7rem 1rem; }
.skip-link:focus { top: 1rem; }

.site-header {
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
  min-height: 5.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}
.brand { display: inline-flex; gap: .75rem; align-items: center; text-decoration: none; font-weight: 800; letter-spacing: -.02em; }
.brand-mark { display: grid; place-items: center; width: 2.25rem; height: 2.25rem; border-radius: .65rem; background: var(--ink); color: var(--mint); }
nav { display: flex; gap: 1.5rem; }
nav a { text-decoration: none; color: var(--muted); font-size: .92rem; font-weight: 650; }
nav a:hover, nav a:focus-visible { color: var(--ink); }

main, footer { width: min(1180px, calc(100% - 2rem)); margin-inline: auto; }
.intro { padding: clamp(5rem, 11vw, 9rem) 0 5rem; max-width: 980px; }
.eyebrow, .section-label { color: #136f5c; font-size: .78rem; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; }
h1 { max-width: 950px; margin: 1rem 0 1.5rem; font-family: Georgia, "Times New Roman", serif; font-size: clamp(3.1rem, 7vw, 6.6rem); font-weight: 500; line-height: .98; letter-spacing: -.055em; }
.intro > p { max-width: 720px; margin: 0; color: var(--muted); font-size: clamp(1.15rem, 2vw, 1.45rem); }
.intro-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin-top: 3rem; }
.intro-stats div { border-top: 2px solid var(--ink); padding-top: .8rem; }
.intro-stats strong { display: block; font-size: 2rem; line-height: 1; }
.intro-stats span { color: var(--muted); font-size: .85rem; }

.findings { display: grid; grid-template-columns: .9fr 1.1fr; gap: clamp(2rem, 8vw, 7rem); background: var(--ink); color: var(--white); padding: clamp(2rem, 5vw, 4rem); border-radius: 1.5rem; box-shadow: var(--shadow); }
.findings h2, .section-heading h2, .method h2, .about h2 { margin: .4rem 0 0; font-family: Georgia, "Times New Roman", serif; font-size: clamp(2rem, 4vw, 3.6rem); line-height: 1.08; letter-spacing: -.035em; font-weight: 500; }
.findings .section-label { color: var(--mint); }
.findings > p { margin: 1.6rem 0 0; color: #d6e2e8; font-size: 1.12rem; }

.research { padding: 7rem 0; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 2rem; margin-bottom: 2rem; }
.filter { display: flex; gap: .4rem; flex-wrap: wrap; justify-content: flex-end; }
.filter button { border: 1px solid var(--line); background: transparent; color: var(--muted); border-radius: 999px; padding: .55rem .9rem; cursor: pointer; font-size: .88rem; font-weight: 700; }
.filter button:hover, .filter button:focus-visible, .filter button.active { background: var(--ink); border-color: var(--ink); color: var(--white); }
.study-list { display: grid; gap: 1.25rem; }
.study { display: grid; grid-template-columns: 1fr .82fr; gap: clamp(1.5rem, 5vw, 4rem); background: var(--white); padding: clamp(1.3rem, 4vw, 2.8rem); border: 1px solid var(--line); border-radius: 1.25rem; align-items: center; }
.study.featured { border-top: 5px solid var(--mint); }
.study[hidden] { display: none; }
.study-meta { display: flex; gap: 1rem; color: var(--muted); font-size: .78rem; font-weight: 750; text-transform: uppercase; letter-spacing: .08em; }
.study-meta span { color: #136f5c; }
.study h3 { margin: .7rem 0 .8rem; font-size: clamp(1.6rem, 3vw, 2.45rem); line-height: 1.1; letter-spacing: -.035em; }
.lead { color: var(--muted); font-size: 1.05rem; }
.metrics { display: flex; gap: 1.5rem; flex-wrap: wrap; margin: 1.5rem 0; }
.metrics div { padding-left: .8rem; border-left: 3px solid var(--gold); }
.metrics dt { color: var(--muted); font-size: .72rem; text-transform: uppercase; letter-spacing: .05em; }
.metrics dd { margin: 0; font-size: 1.15rem; font-weight: 800; }
details { border-top: 1px solid var(--line); padding-top: 1rem; }
summary { cursor: pointer; font-weight: 800; }
details p { color: var(--muted); margin-bottom: 0; }
figure { margin: 0; }
figure img { display: block; width: 100%; height: auto; max-height: 300px; object-fit: contain; background: #f9fbfc; border-radius: .8rem; }
figcaption { color: var(--muted); font-size: .78rem; margin-top: .6rem; }
.empty { text-align: center; color: var(--muted); padding: 3rem; }

.method { display: grid; grid-template-columns: .85fr 1.15fr; gap: clamp(2rem, 8vw, 7rem); padding: 7rem 0; border-top: 1px solid var(--line); }
.method ol { list-style: none; margin: 0; padding: 0; }
.method li { display: grid; grid-template-columns: 3rem 1fr; gap: 1rem; padding: 1.2rem 0; border-bottom: 1px solid var(--line); }
.method li > span { color: #136f5c; font-weight: 800; }
.method strong { font-size: 1.1rem; }
.method p { color: var(--muted); margin: .25rem 0 0; }
.about { margin-bottom: 6rem; background: var(--mint); padding: clamp(2rem, 7vw, 5rem); border-radius: 1.5rem; }
.about p:last-child { max-width: 760px; margin-bottom: 0; font-size: 1.1rem; }
footer { display: flex; justify-content: space-between; gap: 2rem; padding: 2rem 0 3rem; border-top: 1px solid var(--line); color: var(--muted); font-size: .86rem; }
footer span:first-child { color: var(--ink); font-weight: 800; }

@media (max-width: 780px) {
  .site-header { min-height: 4.5rem; }
  nav { gap: .8rem; }
  nav a:nth-child(2) { display: none; }
  .intro { padding-top: 4rem; }
  .intro-stats { grid-template-columns: 1fr; }
  .findings, .study, .method { grid-template-columns: 1fr; }
  .section-heading { align-items: flex-start; flex-direction: column; }
  .filter { justify-content: flex-start; }
  .study figure { order: -1; }
  footer { flex-direction: column; }
}

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