/* =========================================================================
   AICTO — a private colloquium of forty CTOs, Salt Lake City
   Aesthetic: USGS topographic survey x alpine field-notebook x quiet luxury.
   Color: Committed warm — sandstone paper, warm ink, ember/alpenglow accent,
   basalt-dusk dark bands. All OKLCH.
   ========================================================================= */

/* ------------------------------- Tokens -------------------------------- */
:root {
  /* Surfaces */
  --paper:      oklch(0.966 0.009 79);
  --paper-tint: oklch(0.945 0.013 77);
  --paper-deep: oklch(0.915 0.016 75);

  /* Dusk / basalt for dark bands */
  --basalt:     oklch(0.255 0.028 262);
  --basalt-2:   oklch(0.305 0.030 262);
  --on-dark:    oklch(0.935 0.012 82);
  --on-dark-2:  oklch(0.760 0.018 78);

  /* Ink */
  --ink:    oklch(0.245 0.017 58);
  --ink-2:  oklch(0.415 0.020 56);
  --ink-3:  oklch(0.560 0.018 56);

  /* Ember / alpenglow accent */
  --ember:      oklch(0.635 0.163 46);   /* graphics, large type, rules */
  --ember-ink:  oklch(0.505 0.145 42);   /* small text / links on paper (AA) */
  --ember-soft: oklch(0.635 0.163 46 / 0.14);

  /* Hairlines */
  --line:      oklch(0.245 0.017 58 / 0.16);
  --line-soft: oklch(0.245 0.017 58 / 0.09);
  --line-dark: oklch(0.935 0.012 82 / 0.18);

  /* Type */
  --font-display: "Bricolage Grotesque", ui-sans-serif, system-ui, sans-serif;
  --font-body:    "Hanken Grotesk", ui-sans-serif, system-ui, sans-serif;
  --font-mono:    "Spline Sans Mono", ui-monospace, "SFMono-Regular", monospace;

  /* Fluid type scale (~1.28 ratio) */
  --t-mark: clamp(0.68rem, 0.64rem + 0.18vw, 0.78rem);
  --t-body: clamp(1.02rem, 0.98rem + 0.28vw, 1.18rem);
  --t-lede: clamp(1.22rem, 1.08rem + 0.7vw, 1.62rem);
  --t-h3:   clamp(1.3rem, 1.14rem + 0.8vw, 1.85rem);
  --t-disp: clamp(2rem, 1.4rem + 3vw, 3.6rem);
  --t-lg:   clamp(2.9rem, 1.9rem + 5vw, 6rem);
  --t-hero: clamp(3.6rem, 2rem + 10vw, 11rem);

  /* Rhythm */
  --wrap: 76rem;
  --gutter: clamp(1.25rem, 5vw, 6rem);
  --sec-y: clamp(4.5rem, 8vw, 9.5rem);

  --ease: cubic-bezier(0.22, 1, 0.36, 1);   /* ease-out-quint-ish */
}

/* ------------------------------- Reset --------------------------------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--t-body);
  line-height: 1.62;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; height: auto; }
h1, h2, h3 { margin: 0; font-weight: 700; line-height: 1.02; letter-spacing: -0.02em; }
p { margin: 0; }
a { color: inherit; }
::selection { background: var(--ember); color: var(--paper); }

.skip {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--ink); color: var(--paper); padding: 0.75rem 1rem;
  font-family: var(--font-mono); font-size: 0.8rem;
}
.skip:focus { left: 1rem; top: 1rem; }

:focus-visible {
  outline: 2px solid var(--ember);
  outline-offset: 3px;
  border-radius: 1px;
}

/* --------------------------- Shared elements --------------------------- */
.wrap { max-width: var(--wrap); margin-inline: auto; padding-inline: var(--gutter); }

/* The "survey mark" system — mono, tracked, carries real data only. */
.mark {
  font-family: var(--font-mono);
  font-size: var(--t-mark);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.index {
  display: flex; align-items: baseline; gap: 0.9em;
  color: var(--ember-ink);
  margin-bottom: clamp(2rem, 4vw, 3.4rem);
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--line);
}
.index span:first-child {
  font-size: 1.15em;
  color: var(--ember);
}
.section--dark .index { color: var(--ember); border-color: var(--line-dark); }
.section--dark .index span:first-child { color: var(--on-dark); }

.display { font-family: var(--font-display); font-size: var(--t-disp); }
.display--lg { font-size: var(--t-lg); letter-spacing: -0.035em; }

.prose { max-width: 42ch; color: var(--ink-2); }
.prose p + p { margin-top: 1.15em; }
.section--dark .prose { color: var(--on-dark-2); }

.signoff {
  margin-top: 2em; font-family: var(--font-mono); font-size: var(--t-mark);
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--ember-ink);
  display: flex; align-items: center; gap: 0.85em;
}
.signoff::before { content: ""; width: 2.6em; height: 1px; background: currentColor; }

.tbc {
  font-family: var(--font-mono); font-size: 0.82em; letter-spacing: 0.06em;
  color: var(--ember-ink);
  border-bottom: 1px dotted currentColor; padding-bottom: 1px;
}
.section--dark .tbc, .section--tint .tbc { color: var(--ember); }

/* Buttons */
.btn {
  --b: var(--ink);
  display: inline-flex; align-items: center; justify-content: center; gap: 0.6em;
  font-family: var(--font-mono); font-size: 0.82rem; font-weight: 500;
  letter-spacing: 0.08em; text-transform: uppercase; text-decoration: none;
  color: var(--paper); background: var(--b);
  padding: 0.95em 1.5em; border: 1px solid var(--b); border-radius: 2px;
  cursor: pointer;
  transition: transform 0.5s var(--ease), background-color 0.4s var(--ease), color 0.4s var(--ease);
}
.btn:hover { background: var(--ember); border-color: var(--ember); transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn--sm { padding: 0.7em 1.05em; font-size: 0.72rem; }
.btn--block { width: 100%; padding-block: 1.15em; }
.section--dark .btn { --b: var(--on-dark); color: var(--basalt); }
.section--dark .btn:hover { background: var(--ember); border-color: var(--ember); color: var(--paper); }

.link-arrow {
  font-family: var(--font-mono); font-size: 0.82rem; letter-spacing: 0.06em;
  text-transform: uppercase; text-decoration: none; color: var(--ink);
  display: inline-flex; align-items: center; gap: 0.5em; min-height: 44px;
}
.link-arrow::after {
  content: "↓"; transition: transform 0.5s var(--ease);
}
.link-arrow:hover { color: var(--ember-ink); }
.link-arrow:hover::after { transform: translateY(3px); }

/* Reveal-on-scroll (progressive enhancement: only hide when JS is present) */
.js .reveal {
  opacity: 0; transform: translateY(22px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
  will-change: opacity, transform;
}
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* -------------------------------- Nav ---------------------------------- */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 50;
  display: flex; align-items: center; gap: 2rem;
  padding: 1.1rem var(--gutter);
  transition: background-color 0.5s var(--ease), box-shadow 0.5s var(--ease), padding 0.5s var(--ease);
}
.nav.is-stuck {
  background: color-mix(in oklab, var(--paper) 86%, transparent);
  -webkit-backdrop-filter: blur(12px); backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--line-soft);
  padding-block: 0.8rem;
}
.nav__mark {
  display: inline-flex; align-items: center; gap: 0.4em;
  text-decoration: none; color: var(--ink);
  font-family: var(--font-display); font-weight: 700; font-size: 1.15rem;
  letter-spacing: 0.02em; margin-right: auto;
}
.nav__mark-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--ember); }
.nav__links { display: flex; gap: 1.6rem; }
.nav__links a {
  text-decoration: none; color: var(--ink-2);
  font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.04em;
  transition: color 0.3s var(--ease);
}
.nav__links a:hover { color: var(--ember-ink); }
@media (max-width: 860px) { .nav__links { display: none; } }

/* -------------------------------- Hero --------------------------------- */
.flat .hero { min-height: 760px; }
.flat * { scroll-behavior: auto !important; }
.hero {
  position: relative; min-height: 100svh;
  display: flex; flex-direction: column; justify-content: center;
  padding: 8rem var(--gutter) 5rem;
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 78% 8%, oklch(0.97 0.02 70) 0%, transparent 55%),
    var(--paper);
}
.hero__topo { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; }
.hero__glow {
  position: absolute; inset: auto 0 -20% 0; height: 55%; z-index: 1; pointer-events: none;
  background: radial-gradient(80% 100% at 70% 100%, var(--ember-soft) 0%, transparent 70%);
}
.hero__inner { position: relative; z-index: 2; max-width: var(--wrap); margin-inline: auto; width: 100%; }

.hero__coords {
  display: flex; flex-wrap: wrap; gap: 0.5em 0.75em;
  color: var(--ink-3); margin-bottom: clamp(1.4rem, 3vw, 2.4rem);
}
.hero__coords span[aria-hidden] { color: var(--ember); }

.hero__title {
  font-family: var(--font-display);
  font-size: var(--t-hero); font-weight: 700;
  letter-spacing: -0.045em; line-height: 0.9;
  color: var(--ink);
  margin-bottom: clamp(1.4rem, 3vw, 2.2rem);
}
.hero__lede { max-width: 46ch; font-size: var(--t-lede); color: var(--ink-2); line-height: 1.4; }

.hero__meta { margin-top: clamp(2rem, 4vw, 3rem); }
.meta { display: flex; flex-wrap: wrap; gap: 0 clamp(1.5rem, 4vw, 3.5rem); margin: 0; }
.meta > div { padding: 0.2rem 0; }
.meta dt {
  font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--ink-3); margin-bottom: 0.35em;
}
.meta dd { margin: 0; font-family: var(--font-display); font-weight: 600; font-size: 1.28rem; }

.hero__cta {
  display: flex; flex-wrap: wrap; align-items: center; gap: 1.5rem;
  margin-top: clamp(2.2rem, 4vw, 3.2rem);
}

.hero__scroll {
  position: absolute; left: 50%; bottom: 1.6rem; transform: translateX(-50%); z-index: 2;
}
.hero__scroll span {
  font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.28em;
  text-transform: uppercase; color: var(--ink-3);
  animation: sink 2.6s var(--ease) infinite;
}
@keyframes sink { 0%,100% { opacity: 0.3; } 50% { opacity: 1; } }
@media (prefers-reduced-motion: reduce) { .hero__scroll span { animation: none; } }

/* ------------------------------ Sections ------------------------------- */
.section { padding-block: var(--sec-y); position: relative; }
.section--tint { background: var(--paper-tint); }
.section--dark { background: var(--basalt); color: var(--on-dark); }
.section--dark h2, .section--dark h3 { color: var(--on-dark); }

/* 01 · Premise */
.premise__grid {
  display: grid; gap: clamp(2rem, 5vw, 5rem);
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
  align-items: start;
}
.premise__grid .display--lg { position: sticky; top: 6rem; }
@media (max-width: 800px) {
  .premise__grid { grid-template-columns: 1fr; }
  .premise__grid .display--lg { position: static; }
}

/* 02 · Format */
.format__head {
  display: grid; grid-template-columns: minmax(0,1fr) minmax(0,1fr);
  gap: clamp(1.5rem, 4vw, 4rem); align-items: end;
  margin-bottom: clamp(2.5rem, 5vw, 4.5rem);
}
.format__head .prose { align-self: end; }
@media (max-width: 800px) { .format__head { grid-template-columns: 1fr; } }

.rules {
  list-style: none; margin: 0; padding: 0;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr));
  gap: 1px; background: var(--line-dark);
  border: 1px solid var(--line-dark);
}
.rule {
  background: var(--basalt); padding: clamp(1.6rem, 3vw, 2.4rem);
  display: flex; flex-direction: column; gap: 0.6rem;
  transition: background-color 0.5s var(--ease);
}
.rule:hover { background: var(--basalt-2); }
.rule__no {
  color: var(--ember); font-size: 0.9rem; letter-spacing: 0.18em;
}
.rule h3 { font-family: var(--font-display); font-size: var(--t-h3); font-weight: 600; }
.rule p { color: var(--on-dark-2); font-size: 0.98rem; line-height: 1.5; }

/* 03 · The room */
.room__head {
  display: grid; grid-template-columns: minmax(0,1fr) minmax(0,1.1fr);
  gap: clamp(1.5rem, 4vw, 4rem); align-items: end;
  margin-bottom: clamp(2.5rem, 5vw, 4rem);
}
@media (max-width: 800px) { .room__head { grid-template-columns: 1fr; } }

.roster {
  list-style: none; margin: 0; padding: 0;
  display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 15rem), 1fr));
  gap: clamp(1rem, 2vw, 1.4rem);
}
.who {
  border: 1px solid var(--line); border-radius: 2px;
  padding: clamp(1.2rem, 2vw, 1.6rem);
  display: flex; flex-direction: column; gap: 0.75rem; min-height: 9.5rem;
  background: linear-gradient(180deg, transparent, var(--paper-tint));
  transition: transform 0.5s var(--ease), border-color 0.4s var(--ease);
}
.who:hover { transform: translateY(-3px); border-color: var(--ember); }
.who--wide { grid-column: span 2; }
@media (max-width: 560px) { .who--wide { grid-column: span 1; } }
.who .mark { color: var(--ember-ink); }
.who__desc { font-family: var(--font-display); font-weight: 500; font-size: 1.14rem; line-height: 1.25; color: var(--ink); letter-spacing: -0.01em; }
.room__note { margin-top: 2.5rem; color: var(--ink-3); font-size: 0.95rem; max-width: 52ch; }

/* 04 · Place */
.place__head {
  display: grid; grid-template-columns: minmax(0,1fr) minmax(0,1.1fr);
  gap: clamp(1.5rem, 4vw, 4rem); align-items: end;
  margin-bottom: clamp(2rem, 4vw, 3rem);
}
@media (max-width: 800px) { .place__head { grid-template-columns: 1fr; } }

.shot { margin: 0; position: relative; overflow: hidden; }
.shot img { width: 100%; object-fit: cover; }
.shot figcaption {
  position: absolute; left: 0; bottom: 0;
  background: color-mix(in oklab, var(--ink) 82%, transparent);
  color: var(--on-dark); padding: 0.55em 0.9em;
  -webkit-backdrop-filter: blur(4px); backdrop-filter: blur(4px);
}
.shot--hero {
  margin-block: clamp(2rem, 4vw, 3.5rem);
}
.shot--hero img { aspect-ratio: 16 / 8.6; }
.place__pair {
  display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 4rem); align-items: center;
}
.place__pair .shot img { aspect-ratio: 3 / 2; border-radius: 2px; }
@media (max-width: 800px) { .place__pair { grid-template-columns: 1fr; } }

.venue h3 { font-size: var(--t-disp); margin-bottom: 0.8rem; }
.venue .prose { margin-bottom: 1.8rem; }

/* Spec lists (definition data) */
.spec { margin: 0; display: grid; gap: 0; }
.spec > div {
  display: flex; justify-content: space-between; gap: 1.5rem;
  padding: 0.85rem 0; border-top: 1px solid var(--line);
}
.spec > div:last-child { border-bottom: 1px solid var(--line); }
.spec dt {
  font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--ink-3); padding-top: 0.15em;
}
.spec dd { margin: 0; text-align: right; font-weight: 500; }
.spec--roomy > div { padding-block: 1.1rem; }

/* 05 · Stay */
.stay__grid {
  display: grid; grid-template-columns: minmax(0,1fr) minmax(0,1.2fr);
  gap: clamp(2rem, 5vw, 5rem); align-items: start;
}
@media (max-width: 800px) { .stay__grid { grid-template-columns: 1fr; } }
.stay .spec { margin-top: 2rem; }

/* 06 · Program */
.program__intro { margin: 1.5rem 0 clamp(2.5rem, 5vw, 4rem); max-width: 50ch; }
.agenda {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr));
  gap: clamp(1.5rem, 3vw, 2.5rem);
}
.day { border-top: 2px solid var(--ink); padding-top: 1.4rem; }
.day--wide { grid-column: span 1; }
.day__head { margin-bottom: 1.4rem; }
.day__head .mark { color: var(--ember-ink); display: block; margin-bottom: 0.4rem; }
.day__head h3 { font-size: var(--t-h3); font-weight: 600; }
.sched { list-style: none; margin: 0; padding: 0; }
.sched li {
  display: grid; grid-template-columns: 3.6rem 1fr; gap: 1rem;
  padding: 0.7rem 0; border-bottom: 1px solid var(--line-soft);
  font-size: 0.98rem; color: var(--ink-2); line-height: 1.4;
}
.sched__t { color: var(--ink-3); padding-top: 0.15em; }

/* 07 · Reserve */
.reserve { overflow: hidden; }
.reserve__topo { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; opacity: 0.7; }
.reserve__inner { position: relative; z-index: 2; }
.reserve__grid {
  display: grid; grid-template-columns: minmax(0,1fr) minmax(0, 30rem);
  gap: clamp(2.5rem, 5vw, 5rem); align-items: start;
}
@media (max-width: 860px) { .reserve__grid { grid-template-columns: 1fr; } }
.reserve__pitch .prose { margin-top: 1.5rem; }
.reserve__count { margin-top: 2rem; color: var(--ember); }
.reserve__count span { color: var(--on-dark); font-size: 1.1em; }

.rsvp {
  background: color-mix(in oklab, var(--basalt-2) 70%, var(--paper) 4%);
  border: 1px solid var(--line-dark); border-radius: 4px;
  padding: clamp(1.5rem, 3vw, 2.2rem);
  display: flex; flex-direction: column; gap: 1.1rem;
}
.field { display: flex; flex-direction: column; gap: 0.45rem; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1.1rem; }
@media (max-width: 460px) { .field-row { grid-template-columns: 1fr; } }
.field label {
  font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--on-dark-2);
  display: flex; justify-content: space-between; align-items: baseline;
}
.opt { text-transform: none; letter-spacing: 0; font-size: 0.7rem; color: var(--on-dark-2); opacity: 0.7; }
.field input, .field textarea {
  font-family: var(--font-body); font-size: 1rem; color: var(--on-dark);
  background: color-mix(in oklab, var(--basalt) 60%, black 6%);
  border: 1px solid var(--line-dark); border-radius: 2px;
  padding: 0.8em 0.9em; width: 100%; resize: vertical;
  transition: border-color 0.3s var(--ease), background-color 0.3s var(--ease);
}
.field input::placeholder, .field textarea::placeholder { color: var(--on-dark-2); opacity: 0.55; }
.field input:focus, .field textarea:focus {
  outline: none; border-color: var(--ember);
  background: color-mix(in oklab, var(--basalt) 40%, black 4%);
}
.field input:user-invalid { border-color: oklch(0.6 0.16 25); }
.rsvp__fine { font-size: 0.82rem; color: var(--on-dark-2); text-align: center; margin-top: 0.2rem; }
.rsvp__status { font-family: var(--font-mono); font-size: 0.82rem; letter-spacing: 0.03em; text-align: center; min-height: 1.2em; }
.rsvp__status.ok { color: var(--ember); }
.rsvp__status.err { color: oklch(0.72 0.15 30); }
.rsvp.sent { align-items: center; text-align: center; }

/* ------------------------------- Footer -------------------------------- */
.foot { background: var(--basalt); color: var(--on-dark); padding-block: clamp(3rem, 6vw, 5rem); }
.foot__grid {
  display: grid; grid-template-columns: 1.4fr 1fr 1.4fr;
  gap: clamp(2rem, 4vw, 3.5rem); align-items: start;
}
@media (max-width: 760px) { .foot__grid { grid-template-columns: 1fr; } }
.foot .mark { color: var(--on-dark-2); margin-bottom: 0.9rem; }
.foot__mark { font-family: var(--font-display); font-weight: 700; font-size: 2rem; letter-spacing: 0.02em; margin-bottom: 0.7rem; }
.foot__tag { margin-top: 1.2rem; color: var(--on-dark-2); font-size: 0.95rem; }
.foot__col a { color: var(--on-dark); text-decoration: none; border-bottom: 1px solid var(--ember); padding-bottom: 1px; }
.foot__col a:hover { color: var(--ember); }
.foot__credits { font-size: 0.85rem; color: var(--on-dark-2); line-height: 1.55; }
.foot__credits a { color: var(--on-dark-2); border-color: var(--line-dark); }
.foot__credits a:hover { color: var(--ember); border-color: var(--ember); }

/* ------------------------- Mobile refinements -------------------------- */
@media (max-width: 860px) {
  /* comfortable touch targets */
  .nav { gap: 1rem; }
  .btn--sm { min-height: 44px; padding: 0.75em 1.15em; }
}
@media (max-width: 560px) {
  /* stack spec rows so values don't wrap against their labels */
  .spec > div { flex-direction: column; align-items: flex-start; gap: 0.25rem; padding-block: 0.95rem; }
  .spec dd { text-align: left; }
}