/* =========================================================
   AI for Social Good Hackathon – SUST 2026
   GitHub Pages Website Stylesheet
   ========================================================= */

:root {
  --bg: #060816;
  --panel: rgba(255, 255, 255, 0.07);
  --panel-alt: rgba(255, 255, 255, 0.04);
  --text: #f0f4ff;
  --muted: #a8b4e0;
  --primary: #6a7dff;
  --primary-end: #8b5cf6;
  --border: rgba(255, 255, 255, 0.12);
  --highlight: rgba(106, 125, 255, 0.15);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at 20% 10%, #16203b 0%, #080a18 45%, #04050d 100%);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
}

/* ---- Skip-to-main link (accessibility) ---- */
.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--primary);
  color: #fff;
  padding: 10px 18px;
  border-radius: 0 0 8px 0;
  font-weight: 700;
  font-size: 0.9rem;
  text-decoration: none;
  z-index: 9999;
  transition: top 0.2s;
}
.skip-link:focus { top: 0; }

/* Background orbs */
.bg-orb {
  position: fixed; width: 350px; height: 350px; border-radius: 50%;
  filter: blur(60px); opacity: 0.25; z-index: -1;
  animation: float 10s ease-in-out infinite;
}
.orb-1 { background: #5f76ff; top: -100px; left: -80px; }
.orb-2 { background: #8b5cf6; bottom: -100px; right: -80px; animation-delay: -5s; }
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(28px); }
}

.container { width: min(1100px, 92vw); margin: 0 auto; }

/* ---- Navigation ---- */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(6, 8, 22, 0.85);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 0;
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
}
.nav-brand {
  font-weight: 700; font-size: 1rem; color: var(--text);
  text-decoration: none; white-space: nowrap; flex-shrink: 0;
}
.nav-brand:hover { color: var(--primary); }
.nav-links { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.nav-links a {
  color: var(--muted); text-decoration: none; font-size: 0.9rem;
  transition: color 0.2s; padding: 2px 0; border-bottom: 2px solid transparent;
}
.nav-links a:hover, .nav-links a.active { color: var(--text); }
.nav-links a.active { border-bottom-color: var(--primary); }
.nav-links a:focus-visible {
  outline: 2px solid var(--primary); outline-offset: 4px; border-radius: 4px;
}

/* Hamburger toggle button */
.nav-toggle {
  display: none;
  flex-direction: column; justify-content: center; gap: 5px;
  background: none; border: none; cursor: pointer;
  padding: 6px; border-radius: 8px;
  width: 38px; height: 38px; flex-shrink: 0;
  transition: background 0.2s;
}
.nav-toggle:hover { background: var(--panel); }
.nav-toggle:focus-visible {
  outline: 2px solid var(--primary); outline-offset: 2px;
}
.hamburger-bar {
  display: block; width: 22px; height: 2px;
  background: var(--text); border-radius: 2px;
  transition: transform 0.25s, opacity 0.2s;
}
/* Animate to × when open */
.nav-toggle[aria-expanded="true"] .hamburger-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .hamburger-bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .hamburger-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.btn-nav {
  text-decoration: none; padding: 6px 14px; border-radius: 8px;
  font-size: 0.85rem; font-weight: 600; transition: opacity 0.2s;
}
.btn-nav.primary {
  background: linear-gradient(90deg, var(--primary), var(--primary-end));
  color: #fff; border: none;
}
.btn-nav.primary:hover { opacity: 0.85; }
.btn-nav.primary:focus-visible {
  outline: 2px solid #fff; outline-offset: 3px;
}

/* ---- Hero ---- */
.hero {
  text-align: center;
  padding: 80px 0 56px;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.6rem);
  line-height: 1.15;
  margin: 16px 0 12px;
  background: linear-gradient(135deg, #fff 40%, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.subtitle {
  color: var(--muted); font-size: 1.1rem; max-width: 620px; margin: 0 auto 24px;
}
.hero-meta {
  display: flex; justify-content: center; flex-wrap: wrap; gap: 16px;
  margin-bottom: 28px; font-size: 0.95rem; color: var(--muted);
}
.hero-meta span strong { color: var(--text); }

/* ---- Buttons ---- */
.cta-row {
  display: flex; justify-content: center; gap: 12px; flex-wrap: wrap;
}
.btn {
  text-decoration: none; color: var(--text);
  border: 1px solid var(--border);
  padding: 11px 22px; border-radius: 12px;
  background: rgba(255,255,255,0.06);
  font-weight: 600; font-size: 0.95rem;
  transition: background 0.2s, transform 0.15s;
}
.btn:hover { background: rgba(255,255,255,0.1); transform: translateY(-1px); }
.btn:focus-visible { outline: 2px solid var(--primary); outline-offset: 3px; }
.btn.primary {
  background: linear-gradient(90deg, var(--primary), var(--primary-end));
  border: none; color: #fff;
}
.btn.primary:hover { opacity: 0.88; transform: translateY(-1px); }
.btn.large { padding: 14px 28px; font-size: 1rem; }

.pill {
  display: inline-block; padding: 8px 16px; border-radius: 999px;
  background: linear-gradient(90deg, rgba(95,118,255,0.3), rgba(139,92,246,0.3));
  border: 1px solid rgba(139,92,246,0.4);
  font-size: 0.85rem; font-weight: 600; color: #c4b5fd;
  margin-bottom: 8px;
}

/* ---- Sections ---- */
.section { padding: 64px 0; }
.section.alt { background: rgba(255,255,255,0.02); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section-title { font-size: clamp(1.5rem, 3vw, 2.2rem); text-align: center; margin-bottom: 12px; }
.section-desc { color: var(--muted); text-align: center; max-width: 640px; margin: 0 auto 36px; font-size: 1rem; }
.section-desc a { color: var(--primary); }

/* ---- Grid ---- */
.grid { display: grid; gap: 16px; }
.grid.three { grid-template-columns: repeat(3, 1fr); }
.grid.two { grid-template-columns: repeat(2, 1fr); }

/* ---- Cards ---- */
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 18px; padding: 24px;
  transition: transform 0.2s, box-shadow 0.2s;
}
.card-icon { font-size: 2rem; margin-bottom: 10px; }
.card h3 { margin-bottom: 8px; font-size: 1.05rem; }
.card p { color: var(--muted); font-size: 0.92rem; }
.tilt:hover { transform: translateY(-4px); box-shadow: 0 16px 32px rgba(0,0,0,0.3); }
.wide { grid-column: span 2; }

/* ---- Eligibility ---- */
.eligibility-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; max-width: 800px; margin: 0 auto; }
.elig-item {
  display: flex; gap: 14px; align-items: flex-start;
  background: var(--panel); border: 1px solid var(--border); border-radius: 14px; padding: 18px;
}
.elig-icon { font-size: 1.4rem; flex-shrink: 0; }
.elig-item strong { display: block; margin-bottom: 4px; }
.elig-item p { color: var(--muted); font-size: 0.9rem; margin: 0; }

/* ---- Judging ---- */
.judging-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px; max-width: 960px; margin: 0 auto;
}
.judging-item {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 16px; padding: 20px 22px;
}
.judging-header {
  display: flex; align-items: flex-start; gap: 14px; margin-bottom: 10px;
}
.judging-icon { font-size: 1.6rem; flex-shrink: 0; }
.judging-header h3 { font-size: 0.97rem; margin-bottom: 2px; }
.judging-weight {
  font-size: 1.1rem; font-weight: 800;
  color: var(--primary);
  background: linear-gradient(90deg, var(--primary), var(--primary-end));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.judging-item > p { color: var(--muted); font-size: 0.88rem; }
.judging-footnote {
  color: var(--muted); text-align: center; font-size: 0.9rem;
  margin-top: 1.5rem;
}
.judging-footnote a { color: var(--primary); }

/* ---- Prizes ---- */
.prizes-row {
  display: flex; justify-content: center; align-items: flex-end;
  gap: 16px; flex-wrap: wrap; margin-bottom: 20px;
}
.prize-card {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 20px; padding: 28px 32px; text-align: center; min-width: 180px;
}
.prize-card.gold {
  background: linear-gradient(160deg, rgba(250,189,0,0.15), rgba(250,189,0,0.05));
  border-color: rgba(250,189,0,0.4);
  transform: scale(1.08);
}
.prize-card.silver {
  background: linear-gradient(160deg, rgba(160,174,192,0.12), rgba(160,174,192,0.04));
  border-color: rgba(160,174,192,0.3);
}
.prize-card.bronze {
  background: linear-gradient(160deg, rgba(205,127,50,0.12), rgba(205,127,50,0.04));
  border-color: rgba(205,127,50,0.3);
}
.prize-rank { font-size: 1rem; font-weight: 600; margin-bottom: 10px; }
.prize-amount { font-size: 2rem; font-weight: 800; color: #fff; margin-bottom: 8px; }
.prize-cert { font-size: 0.8rem; color: var(--muted); }
.prizes-note { text-align: center; color: var(--muted); font-size: 0.95rem; }

/* ---- Schedule ---- */
.schedule-list { max-width: 700px; margin: 0 auto; }
.sched-item {
  display: flex; gap: 20px; align-items: baseline;
  padding: 12px 16px; border-radius: 10px; border-bottom: 1px solid var(--border);
}
.sched-item:last-child { border-bottom: none; }
.sched-item.highlight { background: var(--highlight); border-color: transparent; border-radius: 10px; }
.sched-time { color: var(--muted); font-size: 0.85rem; min-width: 130px; font-variant-numeric: tabular-nums; }
.sched-event { font-size: 0.97rem; }

/* ---- Sponsors ---- */
.sponsor-section { text-align: center; }
.sponsor-box { display: inline-flex; justify-content: center; margin: 0 auto; }
.sponsor-link {
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  text-decoration: none; padding: 24px 48px;
  background: var(--panel); border: 1px solid var(--border); border-radius: 16px;
  transition: transform 0.2s, box-shadow 0.2s;
}
.sponsor-link:hover { transform: translateY(-3px); box-shadow: 0 12px 28px rgba(0,0,0,0.3); }
.sponsor-link:focus-visible { outline: 2px solid var(--primary); outline-offset: 4px; }
.sponsor-name {
  font-size: 2rem; font-weight: 800;
  background: linear-gradient(90deg, var(--primary), var(--primary-end));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.sponsor-tag { font-size: 0.8rem; color: var(--muted); }

/* ---- FAQ ---- */
.faq-list { max-width: 760px; margin: 0 auto; display: flex; flex-direction: column; gap: 10px; }
.faq-item {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 14px; overflow: hidden;
}
.faq-item summary {
  padding: 16px 20px; font-weight: 600; cursor: pointer;
  list-style: none; display: flex; justify-content: space-between; align-items: center;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 1.2rem; color: var(--primary); transition: transform 0.2s; }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item p { padding: 0 20px 16px; color: var(--muted); font-size: 0.93rem; }
.faq-item summary:focus-visible { outline: 2px solid var(--primary); outline-offset: -4px; border-radius: 14px; }

/* ---- CTA Section ---- */
.cta-section {
  text-align: center;
  background: linear-gradient(135deg, rgba(95,118,255,0.12) 0%, rgba(139,92,246,0.08) 100%);
  border-top: 1px solid rgba(95,118,255,0.3);
  border-bottom: 1px solid rgba(95,118,255,0.3);
}
.cta-section h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); margin-bottom: 12px; }
.cta-section p { color: var(--muted); margin-bottom: 28px; }
.contact-info { margin-top: 20px; color: var(--muted); font-size: 0.9rem; }

/* ---- Footer ---- */
.footer {
  padding: 40px 0 24px;
  border-top: 1px solid var(--border);
  text-align: center;
}
.footer-inner { display: flex; flex-direction: column; gap: 12px; align-items: center; }
.footer p { color: var(--muted); font-size: 0.9rem; line-height: 1.7; }
.footer a { color: var(--primary); text-decoration: none; }
.footer a:hover { text-decoration: underline; }
.footer a:focus-visible { outline: 2px solid var(--primary); outline-offset: 3px; border-radius: 2px; }
.footer-links { font-size: 0.9rem; }
.footer-copy { font-size: 0.8rem; }

/* ---- Responsive ---- */
@media (max-width: 900px) {
  .grid.three { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 700px) {
  .nav-toggle { display: flex; }

  .nav-links {
    display: none;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    background: rgba(6, 8, 22, 0.97);
    border-bottom: 1px solid var(--border);
    padding: 0.5rem 1rem 1rem;
    backdrop-filter: blur(14px);
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    width: 100%;
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
    font-size: 1rem;
  }
  .nav-links a:last-child { border-bottom: none; }
  .btn-nav.primary {
    margin-top: 8px; text-align: center; width: 100%; padding: 10px 0;
  }

  .grid.three, .grid.two { grid-template-columns: 1fr; }
  .wide { grid-column: auto; }
  .eligibility-list { grid-template-columns: 1fr; }
  .prizes-row { flex-direction: column; align-items: center; }
  .prize-card.gold { transform: scale(1); }
  .sched-time { min-width: 100px; }
  .judging-grid { grid-template-columns: 1fr; }
}