/* Frontier '26 — AI Fund co-founder summit
   Brand: Poppins, AI Fund navy + blue (from aifund.ai) */

:root {
  --paper: #f5f8fb;
  --surface: #ffffff;
  --ink: #0a2540;
  --muted: #4f6275;
  --rule: #d6dee7;
  --contour: #a9c6e2;
  --contour-idx: #008fff;
  --accent: #008fff;
  --accent-deep: #004567;
  --accent-ink: #ffffff;
  --summit: #fe5b5a;
  --tbd: #fff1b8;
  --tbd-ink: #5a4a12;
  --portrait-a: #0a2540;
  --portrait-b: #008fff;

  --font: "Poppins", "Helvetica Neue", Helvetica, Arial, system-ui, sans-serif;
  --measure: 42rem;
  --gutter: clamp(1.25rem, 5vw, 3rem);

  box-sizing: border-box;
  padding-top: env(safe-area-inset-top, 0px);
  padding-bottom: env(safe-area-inset-bottom, 0px);
  color-scheme: light;
}

:root[data-theme="dark"] {
  --paper: #0a1a2c;
  --surface: #10233a;
  --ink: #e9f0f7;
  --muted: #a3b4c6;
  --rule: #23384f;
  --contour: #2c4a68;
  --contour-idx: #3ba4ff;
  --accent: #3ba4ff;
  --accent-deep: #6cd4ff;
  --accent-ink: #061524;
  --summit: #ff7a79;
  --tbd: #4a3d0e;
  --tbd-ink: #ffe9a3;
  --portrait-a: #17324f;
  --portrait-b: #3ba4ff;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: inherit; }
html { scroll-padding-top: calc(env(safe-area-inset-top, 0px) + 4.25rem); scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 1rem/1.6 var(--font);
  -webkit-font-smoothing: antialiased;
  transition: background-color .25s ease, color .25s ease;
}
img { max-width: 100%; display: block; }
a { color: var(--accent); text-underline-offset: 0.18em; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; border-radius: 2px; }
.tbd { background: var(--tbd); color: var(--tbd-ink); padding: 0 0.3em; border-radius: 3px; font-weight: 500; }

.wrap { max-width: 70rem; margin: 0 auto; padding: 0 var(--gutter); }

/* ---------- hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--rule);
  --hz: clamp(6rem, 12vw, 9rem);   /* height of the horizon art */
  --bar: 5.25rem;                     /* logo row height */
}
.hero-top {
  z-index: 2;
  position: absolute; top: 0; left: 0; right: 0;
  display: flex; align-items: center; justify-content: space-between;
  padding-top: 1.25rem;
}
.hero-top .logo { width: 128px; height: auto; }
.hero-top .logo.logo--dark { display: none; }
:root[data-theme="dark"] .hero-top .logo--light { display: none; }
:root[data-theme="dark"] .hero-top .logo--dark { display: block; }

.hero-inner {
  position: relative;
  padding-top: calc(var(--bar) + 4rem);
  padding-bottom: 3.5rem;
}
/* Hero backdrop: a fine dot grid that fades toward the headline, with a soft blue wash top-right. */
.horizon {
  position: absolute; left: var(--gutter); right: var(--gutter); top: var(--bar); bottom: 0;
  pointer-events: none;
  background-image: radial-gradient(circle, var(--contour) 1.1px, transparent 1.6px);
  background-size: 20px 20px;
  -webkit-mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 30%, rgba(0,0,0,0) 95%), linear-gradient(to right, rgba(0,0,0,0) 48%, rgba(0,0,0,1) 78%);
  -webkit-mask-composite: source-in;
  mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 30%, rgba(0,0,0,0) 95%), linear-gradient(to right, rgba(0,0,0,0) 48%, rgba(0,0,0,1) 78%);
  mask-composite: intersect;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 55% 60% at 85% 18%, color-mix(in srgb, var(--accent) 16%, transparent), transparent 70%);
  pointer-events: none;
}
.org {
  font: 600 0.8rem/1 var(--font);
  letter-spacing: 0.16em; text-transform: uppercase;
  margin: 0 0 1.25rem; color: var(--accent);
}
h1 {
  font: 700 clamp(3.25rem, 11vw, 7.5rem)/0.9 var(--font);
  letter-spacing: -0.045em;
  margin: 0;
  color: var(--ink);
}
h1 .yr { color: var(--accent); }
.sub {
  font: 300 clamp(1.2rem, 2.8vw, 1.7rem)/1.3 var(--font);
  margin: 1.25rem 0 2rem;
  max-width: 26ch;
}
.when {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: 1rem 2.5rem;
  max-width: 40rem;
  margin: 0; padding: 0; list-style: none;
}
.when li { border-top: 2px solid var(--ink); padding-top: 0.6rem; }
.when strong { display: block; font: 600 1.05rem/1.3 var(--font); }
.when span { color: var(--muted); font-size: 0.95rem; }

/* ---------- theme toggle ---------- */
.theme-toggle {
  appearance: none; border: 1px solid var(--rule); background: var(--surface);
  color: var(--ink); width: 2.5rem; height: 2.5rem; border-radius: 999px;
  display: grid; place-items: center; cursor: pointer; padding: 0;
  box-shadow: 0 1px 2px rgba(10,37,64,.06);
}
.theme-toggle:hover { border-color: var(--accent); color: var(--accent); }
.theme-toggle svg { width: 1.15rem; height: 1.15rem; }
.theme-toggle .moon { display: none; }
:root[data-theme="dark"] .theme-toggle .sun { display: none; }
:root[data-theme="dark"] .theme-toggle .moon { display: block; }

/* ---------- nav ---------- */
nav.sections {
  position: sticky; top: env(safe-area-inset-top, 0px); z-index: 5;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
}
nav.sections ul { display: flex; gap: 1.75rem; margin: 0; padding: 0.95rem 0; list-style: none; overflow-x: auto; scrollbar-width: none; }
nav.sections ul::-webkit-scrollbar { display: none; }
nav.sections a { color: var(--ink); text-decoration: none; font: 500 0.9rem/1 var(--font); white-space: nowrap; }
nav.sections a:hover { color: var(--accent); }
@media (max-width: 40rem) { nav.sections ul { gap: 1.25rem; } }

/* ---------- sections ---------- */
section { padding-block: clamp(3.5rem, 8vw, 6rem); border-bottom: 1px solid var(--rule); }
.eyebrow {
  font: 600 0.75rem/1 var(--font);
  letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--accent); margin: 0 0 0.9rem;
}
h2 {
  font: 700 clamp(2rem, 5.5vw, 3.25rem)/1.05 var(--font);
  letter-spacing: -0.03em;
  margin: 0 0 2.5rem;
}
h3 { font: 600 1.25rem/1.3 var(--font); margin: 0; letter-spacing: -0.01em; }

/* ---------- links in copy ---------- */
.maplink, .slot .who a, .tables a {
  color: var(--accent); font-weight: 500;
  text-decoration: underline; text-decoration-color: var(--accent);
  text-decoration-thickness: 1.5px; text-underline-offset: 0.2em;
}
.maplink:hover, .slot .who a:hover, .tables a:hover { color: var(--accent-deep); text-decoration-color: var(--accent-deep); }
.member:target .portrait { outline: 3px solid var(--accent); outline-offset: 3px; }

/* ---------- agenda ---------- */
.day { margin-bottom: 3.5rem; }
.day:last-child { margin-bottom: 0; }
.day-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 0.25rem 1rem; margin-bottom: 1.25rem; }
.day-head h3 { font-size: 1.5rem; }
.day-head p { margin: 0; color: var(--muted); }

.timeline { list-style: none; margin: 0; padding: 0; position: relative; }
.slot {
  display: grid;
  grid-template-columns: 6.5rem 1fr;
  gap: 0 1.5rem;
  padding: 1.4rem 0;
  border-top: 1px solid var(--rule);
}
.slot time { font: 600 0.95rem/1.5 var(--font); font-variant-numeric: tabular-nums; color: var(--accent-deep); }
.slot .body { max-width: var(--measure); }
.slot .who { margin: 0.35rem 0 0; color: var(--muted); font-size: 0.95rem; }
.slot .desc { margin: 0.6rem 0 0; }
.slot.feature h3 { font-size: 1.45rem; }

.tables { list-style: none; margin: 1rem 0 0; padding: 0; display: grid; gap: 0.5rem; }
.tables li { background: var(--surface); border: 1px solid var(--rule); border-radius: 6px; padding: 0.7rem 0.9rem; }
.tables b { font-weight: 600; }
.fine { font-size: 0.9rem; color: var(--muted); margin: 0.9rem 0 0; }
.btn {
  display: inline-block;
  margin-top: 1.1rem;
  background: var(--accent); color: var(--accent-ink);
  font: 600 0.95rem/1 var(--font);
  padding: 0.9rem 1.3rem; border-radius: 999px;
  text-decoration: none;
}
.btn:hover { filter: brightness(1.08); }

@media (max-width: 34rem) {
  .slot { grid-template-columns: 1fr; }
  .slot time { margin-bottom: 0.3rem; }
}

/* ---------- speakers (grid, like aifund.ai/our-team) ---------- */
.team {
  list-style: none; margin: 0; padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2.5rem 1.25rem;
}
@media (min-width: 40rem) { .team { grid-template-columns: repeat(3, 1fr); gap: 3rem 1.75rem; } }
@media (min-width: 64rem) { .team { grid-template-columns: repeat(3, 1fr); gap: 3.5rem 2.5rem; max-width: 56rem; } }
.member { text-align: center; min-width: 0; }
.member .portrait {
  aspect-ratio: 4 / 5; width: 100%;
  border-radius: 8px;
  background: linear-gradient(160deg, var(--portrait-a), var(--portrait-b));
  box-shadow: 0 8px 22px rgba(10, 37, 64, 0.14);
  display: grid; place-items: center;
  color: #fff; font: 600 1.6rem/1 var(--font); letter-spacing: 0.02em;
  overflow: hidden; margin-bottom: 1rem;
}
.member .portrait img { width: 100%; height: 100%; object-fit: cover; }
.member h3 { font-size: 1.1rem; }
.member .role { margin: 0.25rem 0 0; color: var(--muted); font-size: 0.9rem; line-height: 1.4; }
.member .session { margin: 0.5rem 0 0; font-size: 0.85rem; }
.member .session a { color: var(--accent); text-decoration: none; font-weight: 500; }
.member .session a:hover { text-decoration: underline; }
.member .session time { color: var(--muted); font-weight: 400; font-variant-numeric: tabular-nums; }
.member .bio { margin-top: 0.6rem; text-align: left; }
.member .bio summary {
  list-style: none; cursor: pointer; text-align: center;
  font-size: 0.8rem; font-weight: 600; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--muted);
}
.member .bio summary::-webkit-details-marker { display: none; }
.member .bio summary::after { content: " +"; }
.member .bio[open] summary::after { content: " –"; }
.member .bio summary:hover { color: var(--accent); }
.member .bio p { margin: 0.6rem 0 0; font-size: 0.9rem; line-height: 1.55; }

/* ---------- logistics ---------- */
.places { display: grid; grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr)); gap: 1.25rem; margin-bottom: 2.5rem; }
.place { background: var(--surface); border: 1px solid var(--rule); border-radius: 12px; padding: 1.4rem; }
.place .when-line { margin: 0 0 0.4rem; color: var(--accent-deep); font-size: 0.85rem; font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase; }
.place address { font-style: normal; margin: 0.5rem 0 0.9rem; color: var(--muted); }
.notes { max-width: var(--measure); }
.notes h3 { margin-top: 2rem; font-size: 1.1rem; }
.notes p { margin: 0.5rem 0 0; }

/* ---------- footer ---------- */
footer { padding-block: 2.5rem 3rem; color: var(--muted); font-size: 0.9rem; }
footer .wrap { display: flex; flex-wrap: wrap; align-items: center; gap: 1rem 2rem; }
footer .logo { width: 96px; height: auto; }
footer .logo.logo--dark { display: none; }
:root[data-theme="dark"] footer .logo--light { display: none; }
:root[data-theme="dark"] footer .logo--dark { display: block; }
footer a { color: inherit; }

/* ---------- boba break ---------- */
.body--boba { display: flex; align-items: center; gap: 1rem; }
.boba { width: 3.2rem; height: 4rem; flex: none; overflow: visible; }
.boba-straw { fill: none; stroke: var(--summit); stroke-width: 4; stroke-linecap: round; }
.boba-cup { fill: color-mix(in srgb, var(--accent) 10%, var(--surface)); stroke: var(--ink); stroke-width: 2; stroke-linejoin: round; }
.boba-tea { fill: color-mix(in srgb, var(--accent) 22%, var(--surface)); }
.boba-lid { fill: var(--accent); }
.boba-pearls circle { fill: var(--ink); }
.boba-shine { fill: none; stroke: #fff; stroke-width: 2; stroke-linecap: round; opacity: .7; }
:root[data-theme="dark"] .boba-cup { fill: color-mix(in srgb, var(--accent) 18%, var(--surface)); }
:root[data-theme="dark"] .boba-shine { opacity: .35; }
@media (prefers-reduced-motion: no-preference) {
  .boba { transform-origin: 50% 90%; animation: boba-wiggle 3.2s ease-in-out infinite; }
  .boba-pearls circle { animation: boba-bob 2.4s ease-in-out infinite; }
  .boba-pearls circle:nth-child(2n) { animation-delay: -.8s; }
  .boba-pearls circle:nth-child(3n) { animation-delay: -1.6s; }
  @keyframes boba-wiggle { 0%,100% { transform: rotate(0); } 30% { transform: rotate(-4deg); } 60% { transform: rotate(3deg); } }
  @keyframes boba-bob { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-2px); } }
}