/* =========================================================================
   IIT GOA — 7th CONVOCATION 2026
   STYLE SHEET

   HOW TO RETINT THE PAGE
   Every colour used anywhere on the page is defined once below, in the
   ":root" block. Change a value there and it updates everywhere automatically.
   You do not need to touch anything below the ":root" block to change colours.
   ========================================================================= */

:root {
  /* --- brand colours, taken from the convocation banner --- */
  --purple-deep:   #3d2766;   /* darkest panel backgrounds, footer */
  --purple-brand:  #593d97;   /* primary brand purple (headers, buttons) */
  --purple-tint:   #ece6f7;   /* very light purple, for subtle fills */
  --gold:          #c9943f;   /* accent gold/terracotta, from banner mandala */
  --gold-soft:     #e8c98a;   /* light gold, for hover/border states */
  --cream:         #faf3e6;   /* warm page background, from banner */
  --cream-card:    #fffdf8;   /* near-white card background */
  --ink:           #2a2140;   /* primary text colour */
  --ink-soft:      #5a517a;   /* secondary/muted text */
  --white:         #ffffff;

  /* --- type --- */
  --font-display: 'Cormorant Garamond', Georgia, serif;
  --font-body: 'Work Sans', -apple-system, Segoe UI, sans-serif;

  /* --- shared measurements --- */
  --radius: 10px;
  --shadow-card: 0 8px 24px rgba(58, 38, 90, 0.12);
  --max-width: 1140px;
}

/* ---------- base ---------- */
* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--cream);
  color: var(--ink);
  line-height: 1.65;
}

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

a { color: var(--purple-brand); text-decoration: underline; }
a:hover { color: var(--gold); }

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--purple-deep);
  margin: 0 0 0.5em;
  font-weight: 600;
  font-variant-numeric: lining-nums;
}

h1 { font-size: clamp(1.8rem, 4vw, 2.7rem); }
h2 { font-size: clamp(1.4rem, 3vw, 1.9rem); }
h3 { font-size: 1.3rem; }
h4 { font-size: 1.7rem; font-weight: 700; }

.visually-hidden {
  position: absolute; left: -9999px;
}

/* skip link for keyboard/screen-reader users */
.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--purple-deep); color: var(--white);
  padding: 10px 16px; z-index: 999;
}
.skip-link:focus { left: 0; }

/* ---------- decorative divider (signature element) ----------
   A thin repeating motif echoing the banner's mandala border.
   Pure CSS, no extra image asset needed. */
.motif-divider {
  height: 14px;
  margin: 0 auto 0;
  width: 100%;
  background-image:
    radial-gradient(circle at 7px 7px, var(--gold) 2.5px, transparent 3px);
  background-size: 28px 14px;
  background-repeat: repeat-x;
  opacity: 0.6;
}

/* ---------- top bar ---------- */
.topbar {
  background: var(--purple-deep);
  color: var(--white);
  font-size: 0.85rem;
}
.topbar .wrap {
  display: flex;
  justify-content: flex-end;
  gap: 20px;
  padding: 6px 24px;
  min-height: 18px;
}

/* ---------- header / logo ---------- */
.site-header {
  background: var(--white);
  padding: 18px 0;
  border-bottom: 4px solid var(--gold);
}
.site-header .wrap { display: flex; justify-content: center; }
.site-header img { max-height: 180px; width: auto; }

/* ---------- hero ---------- */
.hero {
  padding: 48px 0 36px;
  text-align: center;
}
.hero h1 { margin-bottom: 22px; }
.hero h1 sup { font-size: 0.55em; }
.hero-banner {
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  max-width: 90%;
  margin-left: auto;
  margin-right: auto;
}
.hero-banner img { width: 100%; }

/* ---------- dignitaries ---------- */
.dignitaries {
  padding: 40px 0 8px;
}
.card-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
}
@media (max-width: 760px) {
  .card-grid-2 { grid-template-columns: 1fr; }
}
.person-card {
  background: var(--cream-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  overflow: hidden;
}
.person-card .card-label {
  background: var(--purple-brand);
  color: var(--white);
  text-align: center;
  padding: 14px 10px;
  font-family: var(--font-display);
  font-size: 1.67rem;
  letter-spacing: 0.02em;
}
.person-card .gold-rule { height: 4px; background: var(--gold); }
.person-card img.person-photo {
  width: 40%;
  height: auto;
  display: block;
  margin: 16px auto 20px;
}
.person-card .person-info {
  padding: 16px 20px;
  text-align: center;
  border-bottom: 1px solid var(--gold-soft);
}
.person-card .person-name {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--purple-brand);
  margin: 0 0 4px;
}
.person-card .person-designation {
  font-family: var(--font-body);
  font-size: 0.92rem;
  color: var(--ink-soft);
  margin: 0;
  line-height: 1.5;
}

/* ---------- quick info cards (date/time, webcast) ---------- */
.quick-info {
  padding: 36px 0 8px;
}
.card-grid-2.quick { gap: 24px; }
.info-card {
  background: var(--cream-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  display: block;
  text-decoration: none;
  color: var(--ink);
  transition: transform 0.15s ease;
}
.info-card:hover { transform: translateY(-3px); }
.info-card .card-label {
  background: var(--purple-brand);
  color: var(--white);
  text-align: center;
  padding: 14px 10px;
  font-family: var(--font-display);
  font-size: 1.67rem;
}
.info-card .gold-rule { height: 4px; background: var(--gold); }
.info-card .card-body { padding: 18px; text-align: center; }
.info-card .info-date {
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 600;
  color: var(--purple-deep);
  margin: 0 0 4px;
  font-variant-numeric: lining-nums;
}
.info-card .info-time {
  font-size: 1.1rem;
  color: var(--ink);
  margin: 0 0 14px;
}
.info-card .info-link {
  font-size: 0.88rem;
  color: var(--purple-brand);
  margin: 0;
}
.yt-icon {
  width: 54px;
  height: 38px;
  display: block;
  margin: 0 auto 10px;
}
.yt-caption {
  font-size: 0.9rem;
  color: var(--ink-soft);
  margin: 0;
  line-height: 1.5;
}

/* ---------- tabs ---------- */
.info-tabs {
  padding: 44px 0 16px;
}
.tab-list {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  border-bottom: 2px solid var(--gold-soft);
  margin-bottom: 0;
}
.tab-btn {
  font-family: var(--font-display);
  font-size: 1.5rem;
  background: var(--purple-tint);
  color: var(--purple-deep);
  border: none;
  border-radius: var(--radius) var(--radius) 0 0;
  padding: 14px 22px;
  cursor: pointer;
  flex: 1 1 220px;
  text-align: center;
}
.tab-btn[aria-selected="true"] {
  background: var(--purple-brand);
  color: var(--white);
}
.tab-btn:focus-visible { outline: 3px solid var(--gold); outline-offset: 2px; }

.tab-panel {
  background: var(--cream-card);
  border-radius: 0 0 var(--radius) var(--radius);
  box-shadow: var(--shadow-card);
  padding: 32px clamp(18px, 4vw, 44px);
}
.tab-panel[hidden] { display: none; }

.tab-panel h3 { color: var(--purple-brand); margin-top: 1.4em; font-size: 1.5rem; }
.tab-panel h3:first-child { margin-top: 0; }
.tab-panel h4 { color: var(--purple-brand); margin-top: 1.2em; font-size: 1.33rem; }
.tab-panel hr {
  border: none;
  border-top: 1px solid var(--gold-soft);
  margin: 24px 0;
}
.tab-panel ol, .tab-panel ul { padding-left: 1.3em; }
.tab-panel li { margin-bottom: 0.6em; }

.intro-note {
  background: var(--purple-tint);
  border-left: 4px solid var(--gold);
  border-radius: 6px;
  padding: 14px 18px;
  margin-bottom: 1.2em;
}

.venue-photo {
  border-radius: var(--radius);
  margin: 0 0 18px;
  max-width: 480px;
  box-shadow: var(--shadow-card);
}

.link-list { list-style: none; padding-left: 0; }
.link-list li { margin-bottom: 0.7em; }

/* ---------- director's video invite ---------- */
.video-invite {
  padding: 44px 0 8px;
}
.video-invite-card {
  background: var(--cream-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  overflow: hidden;
}
.video-invite-card .card-label {
  background: var(--purple-brand);
  color: var(--white);
  text-align: center;
  padding: 14px 10px;
  font-family: var(--font-display);
  font-size: 1.67rem;
  letter-spacing: 0.02em;
}
.video-invite-card .gold-rule { height: 4px; background: var(--gold); }
.video-invite-body {
  padding: 28px clamp(18px, 4vw, 44px);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}
.video-container {
  width: 100%;
  max-width: 720px;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  background: #000;
}
.video-container video {
  width: 100%;
  display: block;
}
.video-invite-caption {
  font-size: 0.95rem;
  color: var(--ink-soft);
  margin: 0;
  text-align: center;
}

/* ---------- programme ---------- */
.programme {
  padding: 44px 0 8px;
}
.programme-card {
  background: var(--cream-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  overflow: hidden;
}
.programme-card .card-label {
  background: var(--purple-brand);
  color: var(--white);
  text-align: center;
  padding: 14px 10px;
  font-family: var(--font-display);
  font-size: 1.67rem;
  letter-spacing: 0.02em;
}
.programme-card .gold-rule { height: 4px; background: var(--gold); }
.programme-body {
  padding: 28px clamp(18px, 4vw, 44px);
}
.programme-list {
  list-style: none;
  counter-reset: prog;
  padding: 0;
  margin: 0 auto;
  max-width: 640px;
}
.programme-list li {
  counter-increment: prog;
  position: relative;
  padding: 10px 0 10px 44px;
  border-bottom: 1px solid var(--gold-soft);
  font-size: 1.05rem;
  color: var(--ink);
}
.programme-list li:last-child { border-bottom: none; }
.programme-list li::before {
  content: counter(prog);
  position: absolute;
  left: 0;
  top: 8px;
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--gold);
  color: var(--purple-deep);
  font-weight: 700;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ---------- footer ---------- */
.site-footer {
  background: var(--purple-deep);
  color: var(--white);
  margin-top: 56px;
  padding: 44px 0 24px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
}
@media (max-width: 760px) {
  .footer-grid { grid-template-columns: 1fr; }
}
.site-footer h4 {
  color: var(--white);
  font-size: 1.1rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.site-footer p, .site-footer a { color: var(--white); }
.site-footer a { text-decoration: none; }
.site-footer a:hover { color: var(--gold-soft); text-decoration: underline; }

.social-row { display: flex; gap: 14px; margin-top: 8px; }
.social-row a {
  width: 38px; height: 38px;
  border-radius: 50%;
  background: rgba(255,255,255,0.12);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem;
}
.social-row a:hover { background: var(--gold); color: var(--purple-deep); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.18);
  margin-top: 28px;
  padding-top: 18px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  font-size: 0.92rem;
}

/* ---------- back to top ---------- */
#backToTop {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--gold);
  color: var(--purple-deep);
  border: none;
  width: 46px; height: 46px;
  border-radius: 50%;
  font-size: 1.2rem;
  cursor: pointer;
  box-shadow: var(--shadow-card);
  display: none;
}
#backToTop.show { display: block; }