/* ============================================================
   Artificial Intelligence Foundation — Core Stylesheet
   ============================================================ */

:root {
  /* Palette */
  --ink:        #14181f;   /* near-black navy ink */
  --ink-soft:   #2a313c;
  --paper:      #f7f5ef;   /* warm paper */
  --paper-pure: #fdfcf9;
  --line:       #d9d4c7;   /* hairline on paper */
  --line-dark:  #323a46;
  --signal:     #c0392b;   /* signal red accent */
  --signal-deep:#992d22;
  --slate:      #5b6470;
  --slate-soft: #8a929d;
  --gold:       #b08322;

  /* Type */
  --serif: "Fraunces", Georgia, "Times New Roman", serif;
  --sans:  "Spline Sans", "Helvetica Neue", Arial, sans-serif;
  --mono:  "Spline Sans Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;

  /* Metrics */
  --maxw: 1240px;
  --gutter: clamp(1.25rem, 4vw, 3rem);
  --radius: 2px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  font-size: 1.0625rem;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { font: inherit; cursor: pointer; border: none; background: none; }

/* Grain / paper texture overlay */
body::before {
  content: "";
  position: fixed; inset: 0;
  pointer-events: none;
  z-index: 9999;
  opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ---------- Typography ---------- */
h1, h2, h3, h4 { font-family: var(--serif); font-weight: 500; line-height: 1.08; letter-spacing: -0.015em; }
h1 { font-size: clamp(2.6rem, 6vw, 5rem); }
h2 { font-size: clamp(1.9rem, 4vw, 3.2rem); }
h3 { font-size: clamp(1.35rem, 2.4vw, 1.9rem); }
h4 { font-size: 1.2rem; }
p  { max-width: 68ch; }

.eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.28em;
  color: var(--signal);
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 0.6em;
}
.eyebrow::before {
  content: ""; width: 1.8em; height: 1px; background: var(--signal);
}

.lede { font-size: clamp(1.15rem, 1.8vw, 1.4rem); line-height: 1.5; color: var(--ink-soft); font-family: var(--serif); font-weight: 400; }

/* ---------- Layout ---------- */
.wrap { max-width: var(--maxw); margin-inline: auto; padding-inline: var(--gutter); }
.section { padding-block: clamp(4rem, 9vw, 8rem); }
.section--tight { padding-block: clamp(3rem, 6vw, 5rem); }
.divider { height: 1px; background: var(--line); border: none; }

.grid { display: grid; gap: clamp(1.5rem, 3vw, 2.5rem); }
.cols-2 { grid-template-columns: repeat(2, 1fr); }
.cols-3 { grid-template-columns: repeat(3, 1fr); }
.cols-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 880px) { .cols-2, .cols-3, .cols-4 { grid-template-columns: 1fr; } }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 0.6em;
  font-family: var(--mono); font-size: 0.8rem; letter-spacing: 0.08em;
  text-transform: uppercase; padding: 0.95em 1.6em;
  border: 1px solid var(--ink); border-radius: var(--radius);
  transition: all 0.4s var(--ease); position: relative; overflow: hidden;
}
.btn--solid { background: var(--ink); color: var(--paper); }
.btn--solid:hover { background: var(--signal); border-color: var(--signal); transform: translateY(-2px); }
.btn--ghost:hover { background: var(--ink); color: var(--paper); transform: translateY(-2px); }
.btn--light { border-color: var(--paper); color: var(--paper); }
.btn--light:hover { background: var(--paper); color: var(--ink); }
.btn .arrow { transition: transform 0.4s var(--ease); }
.btn:hover .arrow { transform: translateX(4px); }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(12px) saturate(1.2);
  border-bottom: 1px solid var(--line);
  transition: transform 0.4s var(--ease);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 78px; }
.brand { display: flex; align-items: center; gap: 0.7rem; font-family: var(--serif); font-weight: 600; font-size: 1.18rem; letter-spacing: -0.01em; }
.brand__mark { width: 34px; height: 34px; flex: none; }
.brand small { display:block; font-family: var(--mono); font-size: 0.56rem; letter-spacing: 0.22em; text-transform: uppercase; color: var(--slate); font-weight:400; }
.nav__links { display: flex; align-items: center; gap: 2rem; }
.nav__links a { font-size: 0.92rem; position: relative; padding: 0.3em 0; }
.nav__links a::after {
  content: ""; position: absolute; left: 0; bottom: -2px; width: 0; height: 1.5px;
  background: var(--signal); transition: width 0.35s var(--ease);
}
.nav__links a:hover::after, .nav__links a[aria-current="page"]::after { width: 100%; }
.nav__cta { display:flex; align-items:center; gap: 1.25rem; }
.nav__toggle { display: none; width: 28px; height: 20px; position: relative; }
.nav__toggle span { position: absolute; left: 0; width: 100%; height: 2px; background: var(--ink); transition: 0.3s var(--ease); }
.nav__toggle span:nth-child(1){ top: 0; } .nav__toggle span:nth-child(2){ top: 9px; } .nav__toggle span:nth-child(3){ top: 18px; }
body.menu-open .nav__toggle span:nth-child(1){ transform: rotate(45deg); top: 9px; }
body.menu-open .nav__toggle span:nth-child(2){ opacity: 0; }
body.menu-open .nav__toggle span:nth-child(3){ transform: rotate(-45deg); top: 9px; }

@media (max-width: 940px) {
  .nav__toggle { display: block; }
  .nav__links {
    position: fixed; inset: 78px 0 auto 0; flex-direction: column; align-items: flex-start;
    gap: 0; background: var(--paper); padding: var(--gutter);
    border-bottom: 1px solid var(--line); transform: translateY(-120%);
    transition: transform 0.45s var(--ease); z-index: 99;
  }
  body.menu-open .nav__links { transform: translateY(0); }
  .nav__links a { width: 100%; padding: 1rem 0; border-bottom: 1px solid var(--line); font-size: 1.1rem; }
  .nav__cta .btn { display: none; }
}

/* ---------- Hero ---------- */
.hero { position: relative; padding-block: clamp(4rem, 10vw, 9rem) clamp(3rem,7vw,6rem); overflow: hidden; }
.hero__grid { position:absolute; inset:0; pointer-events:none; opacity:0.5;
  background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 56px 56px; mask-image: radial-gradient(ellipse 80% 60% at 70% 20%, #000 10%, transparent 75%);
}
.hero h1 { max-width: 16ch; }
.hero .lede { margin-top: 1.8rem; max-width: 54ch; }
.hero__actions { margin-top: 2.6rem; display: flex; gap: 1rem; flex-wrap: wrap; }
.hero__meta { margin-top: 4rem; display: flex; gap: clamp(1.5rem,4vw,3.5rem); flex-wrap: wrap; }
.hero__meta div { border-left: 2px solid var(--signal); padding-left: 1rem; }
.hero__meta .n { font-family: var(--serif); font-size: clamp(1.8rem,3vw,2.6rem); line-height:1; }
.hero__meta .l { font-family: var(--mono); font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.18em; color: var(--slate); margin-top: 0.4rem; }

/* ---------- Cards ---------- */
.card {
  background: var(--paper-pure); border: 1px solid var(--line);
  padding: clamp(1.6rem, 2.5vw, 2.2rem); border-radius: var(--radius);
  transition: transform 0.45s var(--ease), box-shadow 0.45s var(--ease), border-color 0.45s var(--ease);
  position: relative; height: 100%;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 18px 40px -24px rgba(20,24,31,0.45); border-color: var(--ink); }
.card__num { font-family: var(--mono); font-size: 0.72rem; color: var(--signal); letter-spacing: 0.2em; }
.card h3 { margin: 0.8rem 0 0.6rem; }
.card p { color: var(--slate); font-size: 0.98rem; }
.card__link { margin-top: 1.2rem; display: inline-flex; gap: 0.5em; font-family: var(--mono); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--ink); }
.card__link .arrow { transition: transform 0.35s var(--ease); }
.card:hover .card__link .arrow { transform: translateX(4px); }
.card:hover .card__link { color: var(--signal); }

/* ---------- Dark band ---------- */
.band-dark { background: var(--ink); color: var(--paper); position: relative; }
.band-dark .eyebrow { color: #e8a298; }
.band-dark .eyebrow::before { background: #e8a298; }
.band-dark .slate, .band-dark p { color: #aab2bd; }
.band-dark a:not(.btn) { color: var(--paper); }

/* ---------- Pull quote ---------- */
.pullquote { font-family: var(--serif); font-size: clamp(1.6rem, 3.2vw, 2.6rem); line-height: 1.25; letter-spacing:-0.01em; max-width: 24ch; }
.pullquote cite { display:block; margin-top:1.5rem; font-family: var(--mono); font-size:0.78rem; font-style:normal; text-transform:uppercase; letter-spacing:0.14em; color: var(--slate); }

/* ---------- Footer ---------- */
.site-footer { background: var(--ink); color: var(--paper); padding-block: clamp(3.5rem,6vw,5rem) 2rem; }
.footer__top { display: grid; grid-template-columns: 1.4fr repeat(3, 1fr); gap: 2.5rem; }
@media (max-width: 880px){ .footer__top { grid-template-columns: 1fr 1fr; } }
@media (max-width: 520px){ .footer__top { grid-template-columns: 1fr; } }
.site-footer h4 { font-family: var(--mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.18em; color: var(--slate-soft); margin-bottom: 1.2rem; font-weight: 400; }
.site-footer .footcol a { display: block; padding: 0.4rem 0; color: #c4ccd6; font-size: 0.92rem; transition: color 0.3s, padding-left 0.3s; }
.site-footer .footcol a:hover { color: var(--paper); padding-left: 4px; }
.footer__brand p { color: #97a0ab; font-size: 0.92rem; margin-top: 1rem; max-width: 34ch; }
.footer__bottom { margin-top: 3.5rem; padding-top: 1.8rem; border-top: 1px solid var(--line-dark); display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; align-items: center; font-size: 0.8rem; color: var(--slate-soft); font-family: var(--mono); letter-spacing: 0.04em; }
.footer__bottom a { color: var(--slate-soft); }
.footer__bottom a:hover { color: var(--paper); }
.footer__newsletter { display:flex; gap:0; margin-top: 0.5rem; border:1px solid var(--line-dark); border-radius: var(--radius); overflow:hidden; max-width: 320px; }
.footer__newsletter input { flex:1; background: transparent; border:none; padding: 0.8em 1em; color: var(--paper); font-family: var(--sans); font-size: 0.88rem; }
.footer__newsletter input::placeholder { color: var(--slate); }
.footer__newsletter button { background: var(--signal); color: var(--paper); padding: 0 1.2em; font-family: var(--mono); font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.1em; transition: background 0.3s; }
.footer__newsletter button:hover { background: var(--signal-deep); }

/* ---------- Page hero (inner pages) ---------- */
.page-hero { padding-block: clamp(3.5rem,7vw,6rem) clamp(2rem,4vw,3rem); border-bottom: 1px solid var(--line); position: relative; }
.page-hero h1 { max-width: 18ch; margin-top: 1.2rem; }
.page-hero .lede { margin-top: 1.5rem; }
.breadcrumb { font-family: var(--mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.14em; color: var(--slate); display:flex; gap:0.6em; }
.breadcrumb a:hover { color: var(--signal); }

/* ---------- Prose (articles/legal) ---------- */
.prose { max-width: 72ch; }
.prose > * + * { margin-top: 1.4rem; }
.prose h2 { margin-top: 3rem; font-size: clamp(1.6rem,3vw,2.2rem); }
.prose h3 { margin-top: 2.2rem; }
.prose p, .prose li { color: var(--ink-soft); line-height: 1.75; }
.prose ul, .prose ol { padding-left: 1.4rem; }
.prose ul li { list-style: none; position: relative; padding-left: 1.2rem; margin-top: 0.6rem; }
.prose ul li::before { content: "—"; position: absolute; left: 0; color: var(--signal); }
.prose ol { list-style: decimal; }
.prose ol li { margin-top: 0.6rem; padding-left: 0.4rem; }
.prose a { color: var(--signal); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
.prose a:hover { color: var(--signal-deep); }
.prose blockquote { border-left: 3px solid var(--signal); padding-left: 1.4rem; font-family: var(--serif); font-size: 1.3rem; font-style: italic; color: var(--ink); }
.prose strong { font-weight: 600; }
.prose code { font-family: var(--mono); font-size: 0.88em; background: #ece8dd; padding: 0.15em 0.4em; border-radius: 3px; }
.prose figure { margin: 2rem 0; }
.prose figcaption { font-family: var(--mono); font-size: 0.74rem; color: var(--slate); text-transform: uppercase; letter-spacing: 0.1em; margin-top: 0.6rem; }
.prose table { width: 100%; border-collapse: collapse; font-size: 0.95rem; }
.prose th, .prose td { text-align: left; padding: 0.8em 1em; border-bottom: 1px solid var(--line); }
.prose th { font-family: var(--mono); font-size: 0.74rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--slate); }

/* ---------- Article meta / layout ---------- */
.article-layout { display: grid; grid-template-columns: 1fr; gap: 3rem; }
.article-meta { font-family: var(--mono); font-size: 0.76rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--slate); display:flex; gap:1.2rem; flex-wrap:wrap; align-items:center; }
.tag { font-family: var(--mono); font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.12em; padding: 0.35em 0.8em; border: 1px solid var(--line); border-radius: 100px; color: var(--slate); }
.tag--filled { background: var(--ink); color: var(--paper); border-color: var(--ink); }

/* ---------- Article cards (journal index) ---------- */
.journal-card { display: grid; grid-template-columns: 1fr; border: 1px solid var(--line); background: var(--paper-pure); border-radius: var(--radius); overflow: hidden; transition: transform 0.45s var(--ease), box-shadow 0.45s var(--ease); height: 100%; }
.journal-card:hover { transform: translateY(-4px); box-shadow: 0 18px 40px -24px rgba(20,24,31,0.45); }
.journal-card__body { padding: 1.8rem; display:flex; flex-direction:column; height:100%; }
.journal-card h3 { font-size: 1.4rem; margin: 0.9rem 0; }
.journal-card p { color: var(--slate); font-size: 0.95rem; flex: 1; }
.journal-card .article-meta { margin-top: 1.4rem; }
.journal-card__thumb { aspect-ratio: 16/9; position: relative; overflow: hidden; border-bottom:1px solid var(--line); }
.journal-card__thumb svg { width:100%; height:100%; }

/* ---------- Team ---------- */
.person { text-align: left; }
.person__photo { aspect-ratio: 4/5; background: var(--ink); border-radius: var(--radius); overflow:hidden; margin-bottom: 1rem; position:relative; }
.person__photo svg { width: 100%; height: 100%; }
.person h4 { font-family: var(--serif); font-size: 1.2rem; }
.person .role { font-family: var(--mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--signal); margin-top: 0.3rem; }
.person p { font-size: 0.92rem; color: var(--slate); margin-top: 0.7rem; }

/* ---------- Stat band ---------- */
.statband { display:grid; grid-template-columns: repeat(4,1fr); gap:0; border:1px solid var(--line-dark); border-radius: var(--radius); overflow:hidden; }
@media (max-width:760px){ .statband { grid-template-columns: 1fr 1fr; } }
.statband > div { padding: clamp(1.6rem,3vw,2.4rem); border-right:1px solid var(--line-dark); }
.statband > div:last-child { border-right:none; }
@media (max-width:760px){ .statband > div:nth-child(2){ border-right:none; } .statband > div:nth-child(1),.statband>div:nth-child(2){ border-bottom:1px solid var(--line-dark); } }
.statband .n { font-family: var(--serif); font-size: clamp(2.2rem,4vw,3.4rem); line-height:1; }
.statband .l { font-family: var(--mono); font-size:0.72rem; text-transform:uppercase; letter-spacing:0.14em; color: var(--slate-soft); margin-top:0.8rem; }

/* ---------- Accordion (FAQ) ---------- */
.accordion { border-top: 1px solid var(--line); }
.accordion details { border-bottom: 1px solid var(--line); }
.accordion summary { list-style:none; cursor:pointer; padding: 1.5rem 0; display:flex; justify-content:space-between; align-items:center; gap:1rem; font-family: var(--serif); font-size: 1.25rem; }
.accordion summary::-webkit-details-marker { display:none; }
.accordion summary .ico { flex:none; width:22px; height:22px; position:relative; transition: transform 0.35s var(--ease); }
.accordion summary .ico::before,.accordion summary .ico::after { content:""; position:absolute; background: var(--signal); }
.accordion summary .ico::before { top:50%; left:0; width:100%; height:2px; transform:translateY(-50%); }
.accordion summary .ico::after { left:50%; top:0; height:100%; width:2px; transform:translateX(-50%); transition: opacity 0.3s; }
.accordion details[open] summary .ico::after { opacity:0; }
.accordion details[open] summary .ico { transform: rotate(180deg); }
.accordion .acc-body { padding-bottom: 1.6rem; color: var(--slate); max-width: 70ch; }
.accordion .acc-body p + p { margin-top: 1rem; }

/* ---------- Forms ---------- */
.field { margin-bottom: 1.4rem; }
.field label { display:block; font-family: var(--mono); font-size:0.74rem; text-transform:uppercase; letter-spacing:0.12em; color: var(--slate); margin-bottom:0.5rem; }
.field input, .field textarea, .field select {
  width:100%; background: var(--paper-pure); border:1px solid var(--line); border-radius: var(--radius);
  padding: 0.85em 1em; font-family: var(--sans); font-size:1rem; color: var(--ink); transition: border-color 0.3s;
}
.field input:focus, .field textarea:focus, .field select:focus { outline:none; border-color: var(--signal); }

/* ---------- Misc ---------- */
.skip-link { position:absolute; left:-9999px; top:0; background: var(--ink); color:var(--paper); padding:0.8em 1.2em; z-index:10000; }
.skip-link:focus { left:0; }
.kicker-line { display:flex; align-items:baseline; gap:1rem; flex-wrap:wrap; justify-content:space-between; margin-bottom: 2.5rem; }
.text-signal { color: var(--signal); }
.mono { font-family: var(--mono); }
.mt-0{margin-top:0}.center{text-align:center}

/* ---------- Reveal animation ---------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.8s var(--ease), transform 0.8s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity:1; transform:none; transition:none; }
  html { scroll-behavior: auto; }
}