/* ==========================================================================
   The AI Leap — London 2026
   Design system built from Brand Guidelines Ed. 01 — 2026
   Palette: Deep Forest #1B4332 / Slate Navy #2D3142 / Ember Terracotta #D95D39 / Stone Gray #767775
   Type: Lexend (headlines) + Inter (body/UI)
   ========================================================================== */

:root {
  --forest: #1B4332;
  --forest-dark: #123024;
  --navy: #2D3142;
  --terracotta: #D95D39;
  --terracotta-strong: #C35333; /* AA-safe on white for buttons/text */
  --stone: #767775;
  --stone-100: #F4F6F5;
  --stone-200: #E7EAE8;
  --stone-300: #D3D7D4;
  --cream: #F7F9F8;
  --white: #FFFFFF;
  --focus-ring: #0B63CE;

  --font-head: "Lexend", "Segoe UI", sans-serif;
  --font-body: "Inter", "Segoe UI", sans-serif;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;

  --shadow-card: 0 1px 2px rgba(27,67,50,0.06), 0 8px 24px -12px rgba(27,67,50,0.18);
  --shadow-pop: 0 20px 45px -18px rgba(27,67,50,0.35);

  --container: 1180px;
}

/* ---------- Reset & base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; scroll-behavior: auto !important; }
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--navy);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; }
h1, h2, h3, h4 { font-family: var(--font-head); font-weight: 600; line-height: 1.15; margin: 0 0 0.5em; color: var(--forest); }
h1 { font-size: clamp(2.1rem, 4vw, 3.2rem); letter-spacing: -0.01em; }
h2 { font-size: clamp(1.6rem, 2.6vw, 2.1rem); }
h3 { font-size: 1.25rem; }
p { margin: 0 0 1em; }
ul, ol { padding-left: 1.25em; }

.eyebrow {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--terracotta-strong);
  display: inline-block;
  margin-bottom: 0.75em;
}

/* ---------- Skip link (a11y) ---------- */
.skip-link {
  position: absolute;
  left: -999px;
  top: auto;
  background: var(--forest);
  color: var(--white);
  padding: 12px 20px;
  z-index: 1000;
  border-radius: 0 0 8px 0;
  font-weight: 600;
  text-decoration: none;
}
.skip-link:focus {
  left: 0;
  top: 0;
}

/* ---------- Focus visibility (WCAG 2.4.7) ---------- */
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ---------- Layout helpers ---------- */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}
.section { padding: clamp(56px, 8vw, 104px) 0; }
.section-tight { padding: clamp(40px, 5vw, 64px) 0; }
.section-alt { background: var(--stone-100); }
.section-forest { background: var(--forest); color: var(--white); }
.section-forest h2, .section-forest h3 { color: var(--white); }
.section-navy { background: var(--navy); color: var(--white); }
.section-navy h2, .section-navy h3 { color: var(--white); }

.grid { display: grid; gap: 28px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 900px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

.text-center { text-align: center; }
.max-w-content { max-width: 680px; }
.mx-auto { margin-left: auto; margin-right: auto; }
.stack { display: flex; flex-direction: column; gap: 12px; }
.cluster { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 500;
  background: rgba(255,255,255,0.94);
  backdrop-filter: saturate(140%) blur(6px);
  border-bottom: 1px solid var(--stone-200);
}
.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  max-width: var(--container);
  margin: 0 auto;
  gap: 16px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-family: var(--font-head);
  font-weight: 600;
  color: var(--forest);
}
.brand img { height: 40px; width: auto; }
.brand-sub { display: block; font-family: var(--font-body); font-weight: 500; font-size: 0.68rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--stone); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  text-decoration: none;
  font-weight: 600;
  font-size: 0.94rem;
  color: var(--navy);
  padding: 10px 12px;
  border-radius: 8px;
  display: inline-block;
}
.nav-links a:hover { background: var(--stone-100); color: var(--forest); }
.nav-links a[aria-current="page"] { color: var(--forest); background: var(--stone-100); }

.nav-cta { display: flex; align-items: center; gap: 10px; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--stone-300);
  border-radius: 8px;
  padding: 8px 10px;
  cursor: pointer;
}
.nav-toggle svg { display: block; }

@media (max-width: 960px) {
  .nav-links { position: absolute; top: 100%; left: 0; right: 0; background: var(--white); flex-direction: column; align-items: stretch; padding: 8px 16px 16px; border-bottom: 1px solid var(--stone-200); display: none; box-shadow: var(--shadow-card); }
  .nav-links.is-open { display: flex; }
  .nav-links a { padding: 12px; }
  .nav-toggle { display: inline-flex; }
  .nav-cta .btn-label { display: none; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.98rem;
  padding: 13px 24px;
  border-radius: 999px;
  border: 2px solid transparent;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background-color 0.15s ease, color 0.15s ease;
  line-height: 1.1;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn-primary { background: var(--terracotta-strong); color: var(--white); }
.btn-primary:hover { background: #a94528; box-shadow: var(--shadow-pop); }

.btn-secondary { background: var(--forest); color: var(--white); }
.btn-secondary:hover { background: var(--forest-dark); }

.btn-inverted { background: var(--white); color: var(--forest); }
.btn-inverted:hover { background: var(--stone-100); }

.btn-outline { background: transparent; color: var(--forest); border-color: var(--forest); }
.btn-outline:hover { background: var(--forest); color: var(--white); }

.btn-outline-light { background: transparent; color: var(--white); border-color: rgba(255,255,255,0.6); }
.btn-outline-light:hover { background: rgba(255,255,255,0.12); border-color: var(--white); }

.btn-sm { padding: 9px 18px; font-size: 0.86rem; }
.btn-block { width: 100%; }

/* ---------- Tags & labels ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 5px 12px;
  border-radius: 999px;
  background: var(--stone-100);
  color: var(--navy);
  border: 1px solid var(--stone-300);
}
.tag-featured { background: rgba(217,93,57,0.12); color: var(--terracotta-strong); border-color: rgba(217,93,57,0.3); }
.tag-sponsor { background: rgba(27,67,50,0.1); color: var(--forest); border-color: rgba(27,67,50,0.25); }
.tag-outline { background: transparent; color: var(--stone); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(160deg, var(--forest) 0%, var(--forest-dark) 62%, #0f261c 100%);
  color: var(--white);
  padding: clamp(64px, 10vw, 120px) 0 clamp(56px, 8vw, 96px);
}
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle at 82% 20%, rgba(217,93,57,0.18), transparent 45%), radial-gradient(circle at 8% 85%, rgba(255,255,255,0.08), transparent 40%);
  pointer-events: none;
}
.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}
@media (max-width: 900px) { .hero-grid { grid-template-columns: 1fr; } }
.hero h1 { color: var(--white); }
.hero .lede { font-size: 1.15rem; color: rgba(255,255,255,0.86); max-width: 52ch; }
.hero-stats { display: flex; flex-wrap: wrap; gap: 28px; margin-top: 36px; }
.hero-stat strong { display: block; font-family: var(--font-head); font-size: 1.9rem; color: var(--white); }
.hero-stat span { font-size: 0.82rem; color: rgba(255,255,255,0.72); }

.hero-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.16);
  border-radius: var(--radius-lg);
  padding: 28px;
  backdrop-filter: blur(6px);
}
.hero-card h3 { color: var(--white); margin-bottom: 4px; }
.hero-card p { color: rgba(255,255,255,0.78); font-size: 0.94rem; }
.hero-card ul { list-style: none; padding: 0; margin: 18px 0; display: grid; gap: 12px; }
.hero-card li { display: flex; gap: 10px; align-items: flex-start; font-size: 0.92rem; color: rgba(255,255,255,0.9); }
.hero-card li svg { flex-shrink: 0; margin-top: 3px; color: var(--terracotta); }

/* ---------- Cards ---------- */
.card {
  background: var(--white);
  border: 1px solid var(--stone-200);
  border-radius: var(--radius-md);
  padding: 26px;
  box-shadow: var(--shadow-card);
  height: 100%;
}
.card h3 { margin-bottom: 8px; }
.card .icon-badge {
  width: 46px; height: 46px;
  border-radius: 12px;
  background: rgba(27,67,50,0.08);
  color: var(--forest);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 16px;
}

.pillar-card { border-top: 4px solid var(--forest); }
.pillar-card.p2 { border-top-color: var(--navy); }
.pillar-card.p3 { border-top-color: var(--terracotta); }
.pillar-card.p4 { border-top-color: var(--stone); }

/* ---------- Speaker / person cards ---------- */
.person-card {
  background: var(--white);
  border: 1px solid var(--stone-200);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
}
.person-photo {
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, var(--forest) 0%, var(--navy) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-family: var(--font-head);
  font-size: 2.4rem;
  font-weight: 600;
  position: relative;
}
.person-body { padding: 20px 22px 24px; flex: 1; display: flex; flex-direction: column; }
.person-body h3 { margin-bottom: 2px; }
.person-role { color: var(--stone); font-size: 0.88rem; margin-bottom: 10px; }
.person-topic { font-size: 0.9rem; color: var(--navy); background: var(--stone-100); border-radius: 8px; padding: 10px 12px; margin-top: auto; }

/* ---------- Sponsor tiers ---------- */
.tier-card { border: 1px solid var(--stone-200); border-radius: var(--radius-md); padding: 30px; background: var(--white); box-shadow: var(--shadow-card); }
.tier-card.tier-lead { border: 2px solid var(--terracotta-strong); position: relative; }
.tier-price { font-family: var(--font-head); font-size: 1.6rem; color: var(--forest); margin: 6px 0 16px; }
.tier-card ul { list-style: none; padding: 0; margin: 18px 0; display: grid; gap: 10px; }
.tier-card li { display: flex; gap: 10px; font-size: 0.92rem; }
.tier-card li svg { color: var(--forest); flex-shrink: 0; margin-top: 3px; }

.logo-strip { display: flex; flex-wrap: wrap; gap: 16px; align-items: center; justify-content: center; }
.logo-chip { border: 1px solid var(--stone-300); border-radius: 10px; padding: 14px 22px; font-family: var(--font-head); font-weight: 600; color: var(--stone); background: var(--white); }

/* ---------- Steps ---------- */
.steps { counter-reset: step; display: grid; gap: 22px; }
.step { display: flex; gap: 18px; align-items: flex-start; }
.step::before {
  counter-increment: step;
  content: counter(step);
  flex-shrink: 0;
  width: 40px; height: 40px;
  border-radius: 50%;
  background: var(--forest);
  color: var(--white);
  font-family: var(--font-head);
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}

/* ---------- Forms ---------- */
.field { display: flex; flex-direction: column; gap: 6px; margin-bottom: 18px; }
.field label { font-weight: 600; font-size: 0.9rem; color: var(--navy); }
.field .hint { font-size: 0.8rem; color: var(--stone); }
.field input, .field select, .field textarea {
  font-family: var(--font-body);
  font-size: 1rem;
  padding: 12px 14px;
  border-radius: 10px;
  border: 1.5px solid var(--stone-300);
  background: var(--white);
  color: var(--navy);
}
.field input:focus, .field select:focus, .field textarea:focus {
  outline: 3px solid var(--focus-ring);
  outline-offset: 1px;
  border-color: var(--focus-ring);
}
.field textarea { resize: vertical; min-height: 120px; }
fieldset { border: 1px solid var(--stone-300); border-radius: 10px; padding: 16px; margin: 0 0 18px; }
legend { font-weight: 700; padding: 0 8px; }
.checkbox-row { display: flex; align-items: flex-start; gap: 10px; }
.checkbox-row input { margin-top: 4px; }
.form-status { padding: 14px 16px; border-radius: 10px; background: rgba(27,67,50,0.08); color: var(--forest); font-weight: 600; display: none; }
.form-status.is-visible { display: block; }

/* ---------- Search / input with icon (per brand kit) ---------- */
.search-input { position: relative; }
.search-input svg { position: absolute; left: 14px; top: 50%; transform: translateY(-50%); color: var(--stone); }
.search-input input { padding-left: 40px; }

/* ---------- FAQ / accordion ---------- */
.accordion-item { border-bottom: 1px solid var(--stone-200); }
.accordion-trigger {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 18px 4px;
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 1.02rem;
  color: var(--forest);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}
.accordion-trigger svg { transition: transform 0.2s ease; flex-shrink: 0; }
.accordion-trigger[aria-expanded="true"] svg { transform: rotate(180deg); }
.accordion-panel { padding: 0 4px 18px; color: var(--navy); }
.accordion-panel[hidden] { display: none; }

/* ---------- Blog cards ---------- */
.post-card { border: 1px solid var(--stone-200); border-radius: var(--radius-md); overflow: hidden; background: var(--white); box-shadow: var(--shadow-card); display: flex; flex-direction: column; }
.post-thumb { aspect-ratio: 16/9; background: linear-gradient(135deg, var(--stone-200), var(--stone-100)); position: relative; }
.post-thumb .tag { position: absolute; top: 14px; left: 14px; }
.post-body { padding: 20px 22px 24px; display: flex; flex-direction: column; gap: 8px; flex: 1; }
.post-meta { font-size: 0.8rem; color: var(--stone); }
.post-body a.post-link { color: var(--forest); font-weight: 700; text-decoration: none; margin-top: auto; }
.post-body a.post-link:hover { text-decoration: underline; }

/* ---------- CTA band ---------- */
.cta-band {
  background: var(--forest);
  color: var(--white);
  border-radius: var(--radius-lg);
  padding: clamp(36px, 6vw, 56px);
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  align-items: center;
  justify-content: space-between;
}
.cta-band h2 { color: var(--white); margin-bottom: 6px; }
.cta-band p { color: rgba(255,255,255,0.82); margin: 0; }

/* ---------- Footer ---------- */
.site-footer { background: var(--navy); color: rgba(255,255,255,0.85); padding: 56px 0 28px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 32px; }
@media (max-width: 800px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 520px) { .footer-grid { grid-template-columns: 1fr; } }
.site-footer h4 { color: var(--white); font-family: var(--font-head); font-size: 0.95rem; margin-bottom: 14px; }
.site-footer ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.site-footer a { color: rgba(255,255,255,0.78); text-decoration: none; font-size: 0.92rem; }
.site-footer a:hover { color: var(--white); text-decoration: underline; }
.footer-brand { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.footer-brand img { height: 34px; }
.footer-nap { font-size: 0.9rem; color: rgba(255,255,255,0.78); font-style: normal; line-height: 1.7; }
.footer-bottom { margin-top: 40px; padding-top: 24px; border-top: 1px solid rgba(255,255,255,0.14); display: flex; flex-wrap: wrap; gap: 12px 24px; justify-content: space-between; font-size: 0.82rem; color: rgba(255,255,255,0.6); }
.footer-bottom a { color: rgba(255,255,255,0.6); }
.footer-bottom a:hover { color: var(--white); }
.social-row { display: flex; gap: 10px; margin-top: 16px; }
.social-row a { width: 38px; height: 38px; border-radius: 50%; border: 1px solid rgba(255,255,255,0.3); display: flex; align-items: center; justify-content: center; }
.social-row a:hover { background: rgba(255,255,255,0.12); }

/* ---------- Page header (interior pages) ---------- */
.page-hero { background: var(--stone-100); padding: 48px 0 40px; border-bottom: 1px solid var(--stone-200); }
.breadcrumbs { font-size: 0.85rem; color: var(--stone); margin-bottom: 14px; }
.breadcrumbs a { color: var(--stone); text-decoration: underline; }
.breadcrumbs a:hover { color: var(--forest); }

/* ---------- Utility ---------- */
.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;
}
.divider { height: 1px; background: var(--stone-200); border: none; margin: 40px 0; }
.badge-pill { background: var(--stone-200); color: var(--navy); padding: 4px 12px; border-radius: 999px; font-size: 0.78rem; font-weight: 700; }

table.legal-table { width: 100%; border-collapse: collapse; margin: 20px 0; }
table.legal-table th, table.legal-table td { text-align: left; padding: 10px 12px; border: 1px solid var(--stone-300); font-size: 0.92rem; }
table.legal-table th { background: var(--stone-100); }

.toc { background: var(--stone-100); border-radius: var(--radius-md); padding: 20px 24px; margin: 24px 0 36px; }
.toc h2 { font-size: 1rem; margin-bottom: 10px; }
.toc ol { margin: 0; padding-left: 1.2em; }
.toc a { color: var(--forest); text-decoration: none; }
.toc a:hover { text-decoration: underline; }

.map-frame { border: 1px solid var(--stone-200); border-radius: var(--radius-md); overflow: hidden; box-shadow: var(--shadow-card); }
.map-frame iframe { width: 100%; height: 320px; border: 0; display: block; }