/* ==========================================================================
   AI for Educators · Close the Gap Foundation

   Dark and technical. The discipline that keeps it from tipping into cheesy:
     · monospace appears ONLY on data (dates, times, indices, counts), never
       as a decorative eyebrow
     · zero glow, zero gradient blobs, zero shadows, zero glass
     · square corners everywhere; structure comes from hairlines, not cards
     · the logo's colour ramp appears exactly once, inside the logo itself
   ========================================================================== */

:root {
  /* ground · near-black with a blue cast, matching the logo's field */
  --bg: #000b23;
  --surface: #07142e;
  --surface-2: #0d1c3c;
  --line: rgba(234, 240, 248, 0.13);
  --line-2: rgba(234, 240, 248, 0.07);

  /* text · all measured against --bg and --surface */
  --fg: #eaf0f8;
  --dim: rgba(234, 240, 248, 0.68);
  --faint: rgba(234, 240, 248, 0.56);

  /* Close the Gap brand */
  --gold: #edbd46; /* sampled from their favicon mark */
  --gold-dim: #c99c2c;
  --red: #e15d52; /* the mark red · non-text use only */

  /* the event logo's ramp · used once, on the word AI */
  --ramp: linear-gradient(
    100deg,
    #a78bfa 0%,
    #60a5fa 34%,
    #4ade80 66%,
    #fbbf24 100%
  );

  --sans:
    "IBM Plex Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --shell: 1240px;
  --pad: 40px;
}

* {
  box-sizing: border-box;
}
[hidden] {
  display: none !important;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 108px;
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  display: block;
}
a {
  color: inherit;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 300;
  background: var(--gold);
  color: #000b23;
  padding: 12px 20px;
  font-weight: 600;
}
.skip:focus {
  left: 12px;
  top: 12px;
}

:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

.shell {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 var(--pad);
}

/* monospace is for data only */
.u,
.idx,
.specs dd,
.util-in,
.track-n,
.step-n,
.panel-label,
.spk-r,
.sup-note,
.foot-links a {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
}

/* ─────────────────────────────────────────── utility strip */

.util {
  border-bottom: 1px solid var(--line-2);
  background: var(--bg);
}
.util-in {
  display: flex;
  align-items: center;
  gap: 0;
  height: 38px;
  font-size: 11.5px;
  letter-spacing: 0.02em;
  color: var(--faint);
  overflow-x: auto;
  scrollbar-width: none;
  white-space: nowrap;
}
.util-in::-webkit-scrollbar {
  display: none;
}
.util-cell {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding-right: 18px;
}
.util-sep {
  padding-left: 18px;
  border-left: 1px solid var(--line-2);
}
.util .dot {
  width: 6px;
  height: 6px;
  background: var(--gold);
  flex: none;
}
.util-link {
  margin-left: auto;
  padding-left: 18px;
  color: var(--gold);
  text-decoration: none;
  border-left: 1px solid var(--line-2);
}
.util-link:hover {
  color: var(--fg);
}

/* ─────────────────────────────────────────── nav */

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(0, 11, 35, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line-2);
}
.nav-in {
  display: flex;
  align-items: center;
  gap: 32px;
  height: 68px;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  flex: none;
}
.nav-brand img {
  width: 22px;
  height: 22px;
}
.nav-brand span {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.012em;
}
.nav-links {
  display: flex;
  gap: 26px;
  margin-left: auto;
}
.nav-links a {
  font-size: 14.5px;
  color: var(--dim);
  text-decoration: none;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition:
    color 0.14s,
    border-color 0.14s;
}
.nav-links a:hover {
  color: var(--fg);
  border-bottom-color: var(--gold);
}
.nav-toggle {
  display: none;
  margin-left: auto;
  background: none;
  border: 1px solid var(--line);
  width: 42px;
  height: 38px;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}
.nav-toggle span {
  width: 16px;
  height: 1.5px;
  background: var(--fg);
  transition: transform 0.18s;
}
.nav-toggle[aria-expanded="true"] span:first-child {
  transform: translateY(3.25px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:last-child {
  transform: translateY(-3.25px) rotate(-45deg);
}
.nav-mobile {
  display: flex;
  flex-direction: column;
  padding: 8px var(--pad) 22px;
  border-top: 1px solid var(--line-2);
  background: var(--surface);
}
.nav-mobile a:not(.btn) {
  padding: 13px 0;
  font-size: 16.5px;
  color: var(--dim);
  text-decoration: none;
  border-bottom: 1px solid var(--line-2);
}
.nav-mobile .btn {
  margin-top: 16px;
  justify-content: center;
}

/* ─────────────────────────────────────────── buttons */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  font-family: var(--sans);
  font-size: 14.5px;
  font-weight: 600;
  letter-spacing: -0.005em;
  text-decoration: none;
  padding: 11px 20px;
  border: 1px solid transparent;
  cursor: pointer;
  transition:
    background 0.14s,
    border-color 0.14s,
    color 0.14s;
}
.btn-lg {
  font-size: 15.5px;
  padding: 15px 26px;
}
.btn-gold {
  background: var(--gold);
  color: #000b23;
}
.btn-gold:hover {
  background: #f5cd68;
}
.btn-line {
  border-color: var(--line);
  color: var(--fg);
}
.btn-line:hover {
  border-color: var(--faint);
  background: var(--surface);
}
.btn-dark {
  background: #07142e;
  color: var(--fg);
}
.btn-dark:hover {
  background: #00061a;
}

/* ─────────────────────────────────────────── hero */

.hero {
  padding: 84px 0 74px;
  border-bottom: 1px solid var(--line-2);
}

.kicker {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 0 0 34px;
  font-size: 13px;
  color: var(--faint);
  letter-spacing: 0.01em;
}
.kicker .rule {
  width: 34px;
  height: 1px;
  background: var(--gold);
  flex: none;
}

/* the lockup: the client's raster when present, live type until then */
.lockup {
  margin: 0 0 32px;
  font-weight: 400;
  max-width: 900px;
}
.lockup-img {
  display: none;
  width: 100%;
  height: auto;
}
.lockup.has-img .lockup-img {
  display: block;
}
.lockup.has-img .lockup-set {
  display: none;
}

.lk-row {
  display: flex;
  align-items: baseline;
  gap: clamp(12px, 2vw, 24px);
}
.lk-ai {
  font-weight: 700;
  font-size: clamp(3.6rem, 9vw, 7.2rem);
  line-height: 0.86;
  letter-spacing: -0.045em;
  background: var(--ramp);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  flex: none;
}
.lk-for {
  font-weight: 700;
  font-size: clamp(1.6rem, 4.6vw, 3.7rem);
  line-height: 0.94;
  letter-spacing: -0.028em;
  color: var(--fg);
}
.lk-sub {
  display: block;
  margin-top: 16px;
  font-weight: 600;
  font-size: clamp(1rem, 1.9vw, 1.5rem);
  line-height: 1.32;
  letter-spacing: -0.018em;
}
.lk-a {
  color: #7fc4f0;
}
.lk-b {
  color: var(--gold);
}

.hero-lede {
  margin: 0 0 30px;
  font-size: clamp(17px, 1.9vw, 20px);
  line-height: 1.5;
  color: var(--dim);
  max-width: 44ch;
}
.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 56px;
}

/* the spec row · dense, tabular, unmistakably factual */
.specs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin: 0;
  border: 1px solid var(--line-2);
  border-right: 0;
}
.specs > div {
  padding: 16px 20px;
  border-right: 1px solid var(--line-2);
}
.specs dt {
  font-size: 11.5px;
  color: var(--faint);
  margin-bottom: 5px;
  letter-spacing: 0.01em;
}
.specs dd {
  margin: 0;
  font-size: 15.5px;
  font-weight: 500;
  color: var(--fg);
}
.specs .u {
  color: var(--faint);
}

/* ─────────────────────────────────────────── sections */

.band {
  padding: 86px 0;
  border-bottom: 1px solid var(--line-2);
}
.sec-head {
  display: grid;
  grid-template-columns: 60px 1fr;
  align-items: baseline;
  gap: 0 20px;
  margin-bottom: 44px;
}
.idx {
  margin: 0;
  font-size: 13px;
  color: var(--gold);
}
.h2 {
  margin: 0;
  font-size: clamp(1.7rem, 3vw, 2.4rem);
  font-weight: 600;
  letter-spacing: -0.032em;
  line-height: 1.1;
}
.sec-note {
  grid-column: 2;
  margin: 12px 0 0;
  color: var(--faint);
  font-size: 15.5px;
  max-width: 56ch;
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: start;
}
.big-copy {
  margin: 0 0 20px;
  font-size: clamp(19px, 2.1vw, 24px);
  line-height: 1.42;
  letter-spacing: -0.022em;
}
.body-copy {
  margin: 0 0 22px;
  color: var(--dim);
  max-width: 48ch;
}

.panel-label {
  margin: 0 0 16px;
  font-size: 11.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--faint);
}

.who-panel {
  background: var(--surface);
  border: 1px solid var(--line-2);
  padding: 26px 28px 10px;
}
.who {
  list-style: none;
  margin: 0;
  padding: 0;
}
.who li {
  padding: 16px 0;
  border-top: 1px solid var(--line-2);
}
.who li b {
  display: block;
  font-weight: 600;
  font-size: 16px;
  margin-bottom: 3px;
}
.who li span {
  color: var(--faint);
  font-size: 15px;
}

/* ─────────────────────────────────────────── programme */

.tracks {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--line-2);
}
.track {
  padding: 30px 28px 34px;
  border-right: 1px solid var(--line-2);
  transition: background 0.14s;
}
.track:last-child {
  border-right: 0;
}
.track:hover {
  background: var(--surface);
}
.track-n {
  display: block;
  font-size: 12.5px;
  color: var(--gold);
  margin-bottom: 22px;
}
.track h3 {
  margin: 0 0 12px;
  font-size: 21px;
  font-weight: 600;
  letter-spacing: -0.024em;
}
.track p {
  margin: 0;
  color: var(--faint);
  font-size: 15.5px;
  line-height: 1.6;
}

/* ─────────────────────────────────────────── speakers */

.speakers {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.spk-img {
  position: relative;
  aspect-ratio: 1;
  background: var(--surface);
  border: 1px solid var(--line-2);
  overflow: hidden;
  margin-bottom: 16px;
}
.spk-img::after {
  content: attr(data-initials);
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: 30px;
  color: rgba(234, 240, 248, 0.3);
}
.spk-img.has-img::after {
  display: none;
}
.spk-img img {
  display: none;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.spk-img.has-img img {
  display: block;
}
.spk-n {
  margin: 0 0 3px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.018em;
}
.spk-r {
  margin: 0;
  font-size: 12.5px;
  color: var(--faint);
}

/* ─────────────────────────────────────────── steps */

.steps {
  list-style: none;
  margin: 0 0 56px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--line-2);
}
.steps li {
  padding: 28px;
  border-right: 1px solid var(--line-2);
}
.steps li:last-child {
  border-right: 0;
}
.step-n {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border: 1px solid var(--gold);
  color: var(--gold);
  font-size: 12.5px;
  margin-bottom: 20px;
}
.steps h3 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.02em;
}
.steps p {
  margin: 0;
  color: var(--faint);
  font-size: 15px;
}
.step-link {
  display: inline-block;
  margin-top: 12px;
  font-size: 14.5px;
  color: var(--gold);
  text-underline-offset: 3px;
}

/* ─────────────────────────────────────────── questions */

.qa {
  border-top: 1px solid var(--line-2);
}
.qa details {
  border-bottom: 1px solid var(--line-2);
}
.qa summary {
  list-style: none;
  cursor: pointer;
  padding: 20px 34px 20px 0;
  position: relative;
  font-size: 17px;
  font-weight: 500;
  letter-spacing: -0.014em;
}
.qa summary::-webkit-details-marker {
  display: none;
}
.chev {
  position: absolute;
  right: 6px;
  top: 50%;
  width: 9px;
  height: 9px;
  border-right: 1.4px solid var(--faint);
  border-bottom: 1.4px solid var(--faint);
  transform: translateY(-70%) rotate(45deg);
  transition: transform 0.2s;
}
.qa details[open] .chev {
  transform: translateY(-25%) rotate(-135deg);
}
.qa-body {
  padding: 0 34px 22px 0;
}
.qa-body p {
  margin: 0;
  color: var(--faint);
  max-width: 62ch;
}
.qa-body a {
  color: var(--gold);
}

/* ─────────────────────────────────────────── host */

.host-grid {
  display: grid;
  grid-template-columns: 400px 1fr;
  gap: 48px;
  align-items: start;
  margin-bottom: 60px;
}
.host-photo {
  margin: 0;
}
.host-photo img {
  width: 100%;
  height: 250px;
  object-fit: cover;
  border: 1px solid var(--line-2);
}
.host-photo figcaption {
  margin-top: 10px;
  font-size: 13px;
  color: var(--faint);
}
.host-name {
  margin: 0 0 14px;
  font-size: clamp(1.4rem, 2.4vw, 1.9rem);
  font-weight: 600;
  letter-spacing: -0.028em;
}

.supporters {
  border-top: 1px solid var(--line-2);
  padding-top: 30px;
}
/* Supporter wall. Marks are single-path SVGs shipped black, so
   brightness(0) invert(1) renders them as flat white at one optical weight;
   nothing is recoloured into a brand's own palette. Organisations without an
   available mark are set as wordmarks in the same cell, at the same size, so
   the grid stays uniform until real files arrive. */
.sup-grid {
  list-style: none;
  margin: 0 0 18px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  border-top: 1px solid var(--line-2);
  border-left: 1px solid var(--line-2);
}
.sup {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 84px;
  padding: 18px 20px;
  border-right: 1px solid var(--line-2);
  border-bottom: 1px solid var(--line-2);
  transition: background 0.14s;
}
.sup:hover {
  background: var(--surface);
}
/* Each mark ships as a 24×24 square viewBox, so the box is sized square and
   object-fit does the rest. Explicit width matters: with width:auto an SVG
   that has no intrinsic width lays out at zero, which is also why these must
   not be lazy-loaded (a zero-area box may never intersect the viewport). */
.sup img {
  width: 28px;
  height: 28px;
  object-fit: contain;
  filter: brightness(0) invert(1);
  opacity: 0.62;
  transition: opacity 0.14s;
}
/* A wide wordmark sits letterboxed inside that square and reads far smaller
   than a square glyph, so these two get a bigger box to align optically. */
.sup img[src*="intuit"],
.sup img[src*="visa"] {
  width: 76px;
  height: 76px;
}
.sup:hover img {
  opacity: 1;
}
.sup-type span {
  font-size: 14.5px;
  font-weight: 600;
  letter-spacing: -0.012em;
  text-align: center;
  color: var(--dim);
  transition: color 0.14s;
}
.sup-type:hover span {
  color: var(--fg);
}
@media (prefers-reduced-motion: reduce) {
  .sup,
  .sup img,
  .sup-type span {
    transition: none;
  }
}
.sup-note {
  margin: 0;
  font-size: 12.5px;
  color: var(--faint);
  max-width: 60ch;
  line-height: 1.6;
}

/* ─────────────────────────────────────────── register */

.register {
  background: var(--gold);
  color: #000b23;
  padding: 58px 0;
}
.register-in {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  flex-wrap: wrap;
}
.register-h {
  margin: 0 0 6px;
  font-size: clamp(1.8rem, 3.4vw, 2.7rem);
  font-weight: 600;
  letter-spacing: -0.034em;
  line-height: 1.06;
}
.register-sub {
  margin: 0;
  font-family: var(--mono);
  font-size: 13.5px;
  color: #4a3a0c;
}

/* ─────────────────────────────────────────── footer */

.foot {
  background: var(--bg);
  padding: 44px 0;
}
.foot-in {
  display: flex;
  align-items: flex-start;
  gap: 40px;
  flex-wrap: wrap;
}
.foot-mark {
  height: 24px;
  width: auto;
  opacity: 0.8;
}
.foot-meta {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--faint);
}
.foot-links {
  margin: 0 0 0 auto;
  display: flex;
  gap: 22px;
}
.foot-links a {
  font-size: 12.5px;
  color: var(--faint);
  text-decoration: none;
}
.foot-links a:hover {
  color: var(--fg);
}

/* ─────────────────────────────────────────── responsive */

@media (max-width: 1080px) {
  :root {
    --pad: 28px;
  }
  .host-grid {
    grid-template-columns: 320px 1fr;
    gap: 34px;
  }
  .sup-grid {
    grid-template-columns: repeat(4, 1fr);
  }
  
}

@media (max-width: 900px) {
  .nav-links,
  .nav-cta {
    display: none;
  }
  .nav-toggle {
    display: flex;
  }
  .two-col {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .tracks,
  .steps {
    grid-template-columns: 1fr;
  }
  .track,
  .steps li {
    border-right: 0;
    border-bottom: 1px solid var(--line-2);
  }
  .track:last-child,
  .steps li:last-child {
    border-bottom: 0;
  }
  .speakers {
    grid-template-columns: repeat(2, 1fr);
  }
  .host-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 620px) {
  :root {
    --pad: 20px;
  }
  body {
    font-size: 16px;
  }
  .band {
    padding: 58px 0;
  }
  .hero {
    padding: 52px 0 48px;
  }
  .sec-head {
    grid-template-columns: 44px 1fr;
    margin-bottom: 32px;
  }
  .specs {
    grid-template-columns: 1fr;
  }
  .specs > div:nth-child(n + 2) {
    border-top: 1px solid var(--line-2);
  }
  .sup-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .hero-cta .btn {
    width: 100%;
  }
  .lk-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 2px;
  }
  .foot-links {
    margin-left: 0;
    width: 100%;
    flex-direction: column;
    gap: 10px;
  }
}