:root {
  --ink: #202326;
  --muted: #61676d;
  --paper: #ffffff;
  --tint: #f4f5f6;
  --line: #e4e6e8;
  --accent: #f5275b;
  --accent-dark: #d9184b;
  --serif: Georgia, "Times New Roman", serif;
  --sans: "Segoe UI", Arial, Helvetica, sans-serif;
  --shadow: 0 18px 50px rgba(20, 25, 30, .08);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--tint); font-family: var(--sans); font-size: 17px; line-height: 1.62; }
img { display: block; max-width: 100%; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-dark); }
h1, h2, h3, h4, p { margin-top: 0; }
h1, h2, h3 { line-height: 1.14; letter-spacing: -.025em; }
h1 { font-size: clamp(2.4rem, 5vw, 4rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.35rem, 2vw, 1.75rem); }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.skip-link { position: fixed; z-index: 100; top: -60px; left: 1rem; padding: .7rem 1rem; color: #fff; background: var(--accent); }
.skip-link:focus { top: 1rem; }
.container { width: min(1120px, calc(100% - 48px)); margin-inline: auto; }

.site-header { position: relative; z-index: 20; background: var(--paper); border-bottom: 1px solid rgba(0,0,0,.04); }
.site-header--overlay { position: absolute; inset: 0 0 auto; color: #fff; background: transparent; border: 0; }
.nav-shell { width: min(1120px, calc(100% - 48px)); min-height: 76px; margin-inline: auto; display: flex; align-items: center; justify-content: space-between; }
.wordmark { display: inline-grid; width: 44px; height: 44px; place-items: center; border: 2px solid currentColor; border-radius: 50%; color: var(--ink); font-size: .8rem; font-weight: 800; letter-spacing: .08em; }
.site-header--overlay .wordmark { color: #fff; }
.site-nav { display: flex; align-items: center; gap: 2rem; }
.site-nav > a { color: var(--ink); font-size: .96rem; }
.site-header--overlay .site-nav > a { color: #fff; }
.site-nav > a:not(.button) { position: relative; }
.site-nav > a:not(.button)::after { content: ""; position: absolute; right: 0; bottom: -.45rem; left: 0; height: 2px; background: var(--accent); transform: scaleX(0); transition: transform .2s ease; }
.site-nav > a:hover::after, .site-nav > a.active::after { transform: scaleX(1); }
.button { display: inline-flex; align-items: center; justify-content: center; gap: .4rem; min-height: 46px; padding: .7rem 1.5rem; border: 0; border-radius: 999px; color: #fff !important; background: var(--accent); font-size: .9rem; font-weight: 800; letter-spacing: .02em; text-transform: uppercase; transition: transform .2s ease, background .2s ease; }
.button:hover { color: #fff; background: var(--accent-dark); transform: translateY(-1px); }
.menu-toggle { display: none; width: 44px; height: 44px; padding: 10px; border: 0; color: inherit; background: transparent; }
.menu-toggle span:not(.sr-only) { display: block; height: 2px; margin: 5px 0; background: currentColor; }

.hero { min-height: 710px; display: grid; place-items: center; position: relative; color: #fff; background: linear-gradient(rgba(5,8,10,.66), rgba(5,8,10,.66)), url('/assets/images/bpp-hero.jpg') center/cover no-repeat; }
.hero__inner { width: min(1120px, calc(100% - 48px)); padding: 130px 0 60px; text-align: center; }
.hero h1 { margin-bottom: 2.6rem; font-weight: 800; }
.hero p { max-width: 1040px; margin: 0 auto; font-size: clamp(1.18rem, 2.2vw, 1.55rem); font-weight: 700; line-height: 1.45; }
.hero a { font-weight: 800; }
.accent-line { width: 176px; height: 3px; margin: 0 auto 2rem; background: var(--accent); }

.section { padding: 100px 0; background: var(--paper); }
.section--tint { background: var(--tint); }
.section .container > h2 { margin-bottom: 3.3rem; }
.eyebrow { margin-bottom: .45rem; color: var(--accent); font-size: .78rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
.card-grid { display: grid; gap: 2rem; }
.card-grid--two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.image-card { overflow: hidden; background: #fff; border: 1px solid var(--line); border-radius: 4px; box-shadow: var(--shadow); }
.image-card__media { display: block; aspect-ratio: 16/10; overflow: hidden; background: #e9eaeb; }
.image-card__media img { width: 100%; height: 100%; object-fit: cover; transition: transform .35s ease; }
.image-card:hover .image-card__media img { transform: scale(1.025); }
.image-card__body { padding: 2rem; }
.image-card__body h3 { margin-bottom: .8rem; }
.image-card__body h3 a { color: var(--ink); }
.text-link { font-size: .9rem; font-weight: 800; text-transform: uppercase; letter-spacing: .04em; }

.feature-band { padding: 90px 0; background: #1d2023; color: #fff; }
.feature-band__inner { display: grid; grid-template-columns: .9fr 1.1fr; align-items: center; gap: 5rem; }
.feature-band__image img { width: 100%; box-shadow: 0 18px 50px rgba(0,0,0,.3); }
.feature-band h2 { margin-bottom: 1rem; }
.feature-band p:not(.eyebrow) { color: #d3d6d8; }
.feature-band .button { margin-top: .6rem; }

.page-main { padding: 58px 0 100px; }
.page-shell { width: min(1120px, calc(100% - 48px)); margin-inline: auto; padding: 70px 56px; background: #fff; box-shadow: 0 8px 32px rgba(30,35,40,.035); }
.page-title { margin-bottom: 3.5rem; font-size: clamp(2rem, 4vw, 3.15rem); }
.page-title::after { content: ""; display: block; width: 74px; height: 3px; margin-top: 1rem; background: var(--accent); }

.research-list, .dataset-list { display: grid; gap: 0; }
.research-item { display: grid; grid-template-columns: 250px 1fr; gap: 3.5rem; padding: 3.5rem 0; border-top: 1px solid var(--line); }
.research-item:first-child { padding-top: 0; border-top: 0; }
.research-item__media { align-self: start; border: 1px solid var(--line); background: var(--tint); }
.research-item__media img { width: 100%; max-height: 310px; object-fit: contain; }
.research-item h2 { margin-bottom: .65rem; font-size: clamp(1.55rem, 2.8vw, 2.1rem); }
.research-item__authors { margin-bottom: .15rem; font-weight: 700; }
.research-item__publication { margin-bottom: .9rem; color: var(--muted); font-size: .94rem; font-style: italic; }
.research-item__links { display: flex; flex-wrap: wrap; gap: .4rem .9rem; margin-bottom: 1.1rem; }
.research-item__links a, .download-link { font-weight: 800; }
.research-item__summary { color: #3d4246; }
.research-item__summary:last-child { margin-bottom: 0; }

.dataset-item { display: grid; grid-template-columns: 390px 1fr; gap: 4rem; padding: 3.8rem 0; border-top: 1px solid var(--line); }
.dataset-item:first-child { padding-top: 0; border-top: 0; }
.dataset-item:nth-child(even) { grid-template-columns: 1fr 390px; }
.dataset-item:nth-child(even) .dataset-item__media { order: 2; }
.dataset-item__media { align-self: start; background: var(--tint); }
.dataset-item__media img { width: 100%; max-height: 330px; object-fit: contain; }
.dataset-item h2 { margin-bottom: 1rem; font-size: clamp(1.65rem, 3vw, 2.2rem); }
.dataset-item ul { padding-left: 1.2rem; color: var(--muted); }
.dataset-item .download-link { display: inline-block; margin-top: .35rem; }

.site-footer { padding: 28px 0; color: #c4c8cb; background: #111315; font-size: .84rem; }
.site-footer .container { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.site-footer p { margin: 0; }
.site-footer__note { color: #858b90; }

@media (max-width: 820px) {
  body { font-size: 16px; }
  .container, .nav-shell, .hero__inner, .page-shell { width: min(100% - 32px, 1120px); }
  .menu-toggle { display: block; position: relative; z-index: 2; color: var(--ink); cursor: pointer; }
  .site-header--overlay .menu-toggle { color: #fff; }
  .site-header.menu-open .menu-toggle { color: var(--ink); }
  .wordmark { width: 40px; height: 40px; }
  .site-nav { display: none; position: absolute; inset: 0 0 auto; padding: 82px 24px 26px; flex-direction: column; align-items: stretch; gap: .1rem; background: #fff; box-shadow: var(--shadow); }
  .site-header.menu-open .site-nav { display: flex; }
  .site-nav > a, .site-header--overlay .site-nav > a { padding: .7rem 0; color: var(--ink); }
  .site-nav > .button { margin-top: .7rem; }
  .hero { min-height: 640px; }
  .hero__inner { padding-top: 120px; }
  .section { padding: 72px 0; }
  .card-grid--two, .feature-band__inner { grid-template-columns: 1fr; }
  .feature-band__inner { gap: 2.5rem; }
  .page-main { padding: 24px 0 60px; }
  .page-shell { padding: 48px 28px; }
  .research-item, .dataset-item, .dataset-item:nth-child(even) { grid-template-columns: 1fr; gap: 1.8rem; }
  .research-item__media { width: min(100%, 300px); }
  .dataset-item:nth-child(even) .dataset-item__media { order: 0; }
  .site-footer .container { align-items: flex-start; flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}