/* HAI Hackathon 2026 participant hub
   Look follows houstonaiinstitute.com: forest green, mint bands, gold labels,
   serif headings, pill buttons. System fonts only: no font downloads. */

:root {
  --green: #2c6d50;
  --green-dark: #1b4130;
  --green-ink: #1f5a40;
  --mint: #f3f7f4;
  --mint-2: #e6efe9;
  --gold: #d29d41;
  --gold-ink: #7a5410;
  --gold-tint: #f8edd9;
  --ink: #1a1a1a;
  --muted: #4b5563;
  --line: #e2e6e3;
  --bg: #ffffff;
  --surface: #ffffff;
  --btn-bg: #2c6d50;
  --btn-ink: #ffffff;
  --link: #1f5a40;
  --focus: #1f5a40;
  --shadow: 0 1px 2px rgba(16, 40, 28, 0.06), 0 6px 20px rgba(16, 40, 28, 0.06);
  --radius: 18px;
  --serif: "DM Serif Display", Georgia, "Times New Roman", serif;
  --sans: Poppins, system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --green: #7ccba2;
    --green-dark: #1b4130;
    --green-ink: #9fdcbb;
    --mint: #16281f;
    --mint-2: #22392d;
    --gold-ink: #f0c983;
    --gold-tint: #33291a;
    --ink: #e7efea;
    --muted: #b3c2b9;
    --line: #36503f;
    --bg: #0e1a14;
    --surface: #1a2e24;
    --btn-bg: #7ccba2;
    --btn-ink: #0e1a14;
    --link: #9fdcbb;
    --focus: #d29d41;
    --shadow: none;
  }
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-padding-top: 112px; }
main:focus { outline: none; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.5;
  overflow-wrap: break-word;
}

img, svg { max-width: 100%; }

a { color: var(--link); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 6px;
}

h1, h2, h3 { line-height: 1.15; margin: 0 0 0.5em; }
h1, h2 { font-family: var(--serif); font-weight: 400; letter-spacing: -0.01em; }
h1 { font-size: clamp(2.1rem, 7vw, 3.6rem); }
h2 { font-size: clamp(1.6rem, 4.5vw, 2.3rem); margin-top: 0.2em; }
h3 { font-size: 1.15rem; font-weight: 700; }
p { margin: 0 0 1em; }
ul, ol { padding-left: 1.3em; margin: 0 0 1em; }
li { margin-bottom: 0.35em; }

.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;
}

.skip-link {
  position: absolute; left: 12px; top: -60px; z-index: 100;
  background: var(--btn-bg); color: var(--btn-ink);
  padding: 10px 16px; border-radius: 999px; font-weight: 600;
}
.skip-link:focus { top: 12px; }

.wrap { width: 100%; max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--bg);
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(8px);
  backdrop-filter: saturate(1.4) blur(8px);
  border-bottom: 1px solid var(--line);
}
.header-row {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; min-height: 64px; flex-wrap: wrap;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--ink); text-decoration: none; font-weight: 700;
  min-height: 44px;
}
.brand-mark { width: 34px; height: 34px; flex: none; }
.brand-text { line-height: 1.1; font-size: 1rem; }
.brand-text small { display: block; font-weight: 400; color: var(--muted); font-size: 0.8rem; }

.menu-toggle { display: none; }

.site-nav ul {
  list-style: none; margin: 0; padding: 0;
  display: flex; flex-wrap: wrap; gap: 2px 4px;
}
.site-nav li { margin: 0; }
.site-nav a {
  display: inline-flex; align-items: center; min-height: 44px;
  padding: 0 12px; border-radius: 999px;
  color: var(--ink); text-decoration: none; font-size: 0.95rem;
}
.site-nav a:hover { background: var(--mint); }
.site-nav a[aria-current="page"], .site-nav a[aria-current="true"] { background: var(--mint-2); color: var(--green-ink); font-weight: 600; }

/* Without JS the nav is a wrapped list under the brand (always reachable).
   With JS on small screens it folds behind the Menu button. */
@media (max-width: 899px) {
  .site-nav { width: 100%; padding-bottom: 8px; }
  .js .menu-toggle {
    display: inline-flex; align-items: center; gap: 8px;
    min-height: 44px; padding: 0 16px; border-radius: 999px;
    border: 1px solid var(--line); background: var(--surface); color: var(--ink);
    font: inherit; font-weight: 600; cursor: pointer;
  }
  .js .site-nav { display: none; }
  .js .site-nav.open { display: block; }
  .js .site-nav ul { flex-direction: column; }
  .js .site-nav a { width: 100%; }
}
@media (min-width: 900px) {
  .site-nav { width: auto; }
}

/* Hero and page heads */
.hero, .page-head {
  background: var(--mint);
  border-bottom: 1px solid var(--line);
}
.hero { padding: 48px 0 44px; }
.page-head { padding: 36px 0 28px; }
.hero .lead, .page-head .lead { font-size: 1.12rem; color: var(--muted); max-width: 46rem; }

.eyebrow {
  display: inline-block; margin: 0 0 14px;
  background: var(--gold-tint); color: var(--gold-ink);
  border: 1px solid color-mix(in srgb, var(--gold) 35%, transparent);
  padding: 4px 12px; border-radius: 999px;
  font-size: 0.85rem; font-weight: 600;
}

.banner {
  display: flex; gap: 12px; align-items: flex-start;
  margin: 20px 0 0; padding: 14px 16px;
  background: var(--surface); border: 1px solid var(--line);
  border-left: 5px solid var(--gold); border-radius: 12px;
  max-width: 46rem;
}
.banner p { margin: 0; }

.note {
  padding: 14px 16px; margin: 0 0 1.2em;
  background: var(--gold-tint); border-radius: 12px;
  border-left: 5px solid var(--gold);
}
.note p:last-child { margin: 0; }

/* Buttons */
.btn-row { display: flex; flex-wrap: wrap; gap: 10px; margin: 22px 0 0; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 48px; padding: 0 22px; border-radius: 999px;
  background: var(--btn-bg); color: var(--btn-ink);
  font-weight: 600; text-decoration: none; border: 2px solid var(--btn-bg);
}
.btn:hover { filter: brightness(1.08); }
.btn-ghost { background: transparent; color: var(--green-ink); border-color: var(--green); }
.btn-ghost:hover { background: var(--mint-2); filter: none; }
.btn svg { width: 18px; height: 18px; flex: none; }

/* Sections */
main { display: block; }
.section { padding: 40px 0; }
.section + .section { padding-top: 8px; }
.section.band { background: var(--mint); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); padding-top: 40px; }
.section-intro { color: var(--muted); max-width: 46rem; }

/* Cards and grids */
.grid { display: grid; gap: 16px; grid-template-columns: 1fr; }
.grid > * { min-width: 0; }
@media (min-width: 768px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
}
.card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow);
}
.card h3 { margin-bottom: 0.4em; }
.card-title {
  font-family: var(--sans); font-weight: 700; font-size: 1.2rem;
  letter-spacing: 0; margin: 0 0 0.45em;
}
.card p:last-child, .card ul:last-child { margin-bottom: 0; }
.card-icon {
  width: 46px; height: 46px; border-radius: 12px;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--mint-2); color: var(--green-ink); margin-bottom: 12px;
}
.card-icon svg { width: 26px; height: 26px; }
.card .points {
  display: inline-block; font-family: var(--serif); font-size: 2rem; line-height: 1;
  color: var(--green-ink); margin-bottom: 6px;
}
.card .points small { font-family: var(--sans); font-size: 0.9rem; color: var(--muted); }

.track-head { display: flex; gap: 14px; align-items: flex-start; }
.track-head .card-icon { margin: 0; }
.track-num { display: block; font-size: 0.85rem; font-weight: 600; color: var(--gold-ink); }
.challenge-list { list-style: none; padding: 0; margin: 14px 0 0; }
.challenge-list li { padding: 10px 0; border-top: 1px solid var(--line); margin: 0; }
.challenge-list a { font-weight: 600; }
.open-track { margin: 14px 0 0; padding-top: 12px; border-top: 1px solid var(--line); color: var(--muted); }

.tag {
  display: inline-block; vertical-align: middle; margin-left: 4px;
  padding: 2px 10px; border-radius: 999px; font-size: 0.78rem; font-weight: 600;
  background: var(--mint-2); color: var(--green-ink); white-space: nowrap;
}
.tag:first-child { margin-left: 0; }
.tag-code { background: var(--gold-tint); color: var(--gold-ink); }
.tag-partner { background: var(--btn-bg); color: var(--btn-ink); }
#partner-challenges .card-title a { text-decoration: none; }
#partner-challenges .card-title a:hover { text-decoration: underline; }

/* Tables */
.table-wrap { overflow-x: auto; margin: 0 0 1.2em; border: 1px solid var(--line); border-radius: 14px; background: var(--surface); }
table { border-collapse: collapse; width: 100%; font-size: 0.95rem; }
caption { text-align: left; font-weight: 700; padding: 12px 14px 0; }
th, td { text-align: left; vertical-align: top; padding: 10px 14px; border-bottom: 1px solid var(--line); }
th { background: var(--mint); font-weight: 600; }
tr:last-child td { border-bottom: 0; }
.schedule td:first-child, .schedule th:first-child { white-space: nowrap; font-weight: 600; width: 5.5rem; }

/* Phone: data tables become stacked cards so nothing scrolls sideways */
@media (max-width: 899px) {
  .stack, .stack tbody { display: block; }
  .stack thead { position: absolute; left: -9999px; }
  .stack tr { display: block; padding: 10px 0; border-bottom: 1px solid var(--line); }
  .stack tr:last-child { border-bottom: 0; }
  .stack td { display: block; border: 0; padding: 4px 14px; overflow-wrap: anywhere; }
  .stack td::before { content: attr(data-label); display: block; font-size: 0.8rem; font-weight: 600; color: var(--muted); }
  .stack td:first-child { font-weight: 700; }
}

/* Steps */
.steps { counter-reset: step; list-style: none; padding: 0; }
.steps > li {
  counter-increment: step; position: relative; padding: 0 0 0 52px; margin: 0 0 18px; min-height: 40px;
}
.steps > li::before {
  content: counter(step); position: absolute; left: 0; top: -2px;
  width: 38px; height: 38px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background: var(--btn-bg); color: var(--btn-ink); font-weight: 700;
}

/* Details */
details {
  background: var(--surface); border: 1px solid var(--line); border-radius: 14px;
  margin: 0 0 12px; padding: 0 16px;
}
summary {
  cursor: pointer; font-weight: 600; min-height: 48px; display: flex; align-items: center;
  gap: 12px; padding: 10px 0; list-style: none;
}
summary::-webkit-details-marker { display: none; }
summary::after {
  content: "+"; margin-left: auto; flex: none;
  font-size: 1.5rem; line-height: 1; color: var(--green-ink);
}
details[open] > summary::after { content: "\2212"; }
details[open] summary { border-bottom: 1px solid var(--line); margin-bottom: 12px; }
details > *:last-child { margin-bottom: 14px; }

.meta-list { list-style: none; padding: 0; margin: 0; }
.meta-list li { margin: 0 0 8px; }
.meta-list strong { display: inline-block; min-width: 6.5rem; }

/* Footer */
.site-footer {
  margin-top: 48px; background: var(--green-dark); color: #e9f2ec;
  padding: 32px 0 28px; font-size: 0.95rem;
}
.site-footer a { color: #ffffff; }
.site-footer p { margin: 0 0 0.6em; }
.site-footer .small { color: #c6d6cc; font-size: 0.85rem; }

@media print {
  .site-header, .menu-toggle, .skip-link { position: static; }
  .site-footer { background: none; color: #000; }
}

/* Key facts under each free tool */
.facts { margin: 14px 0 0; padding-top: 12px; border-top: 1px solid var(--line); font-size: 0.92rem; }
.facts dt { font-weight: 600; color: var(--muted); }
.facts dd { margin: 0 0 8px; }
.facts dd:last-child { margin-bottom: 0; }
.card ol { padding-left: 1.3em; }

/* Jump links at the top of long pages */
.jump { display: flex; flex-wrap: wrap; gap: 8px; margin: 18px 0 0; padding: 0; list-style: none; }
.jump li { margin: 0; }
.jump a {
  display: inline-flex; align-items: center; min-height: 44px; padding: 0 16px;
  border-radius: 999px; border: 1px solid var(--line); background: var(--surface);
  text-decoration: none; font-weight: 600; font-size: 0.95rem;
}
.jump a:hover { background: var(--mint-2); }

/* Bigger tap area for a link that sits alone in a card paragraph */
.card > p > a:only-child { display: inline-flex; align-items: center; min-height: 44px; }

/* Short code blocks */
pre {
  margin: 0 0 1em; padding: 10px 12px; overflow-x: auto;
  background: var(--mint); border: 1px solid var(--line); border-radius: 10px; font-size: 0.9rem;
}

/* Phones without JS: the nav stays open, so the header is too tall to stick. */
@media (max-width: 899px) {
  html:not(.js) .site-header { position: static; }
}