/* ============================================================
   IASTA 2026 — Design tokens
   Palette drawn from the physics of the subject: a hazy sky
   (sky/paper), suspended particulate matter (amber = pollutant,
   sage = clean air / mitigation), and Tyndall scattering (blue).
   ============================================================ */

:root {
  --sky: #e9f1f2;
  --sky-deep: #d8e6e6;
  --paper: #fbfaf6;
  --ink: #12242b;
  --ink-soft: #4a5c60;
  --line: rgba(18, 36, 43, 0.13);
  --line-strong: rgba(18, 36, 43, 0.24);

  --haze-amber: #d97e2e;
  --haze-amber-soft: rgba(217, 126, 46, 0.14);
  --clean-sage: #4c8670;
  --clean-sage-soft: rgba(76, 134, 112, 0.14);
  --scatter-blue: #2c6b8a;
  --scatter-blue-soft: rgba(44, 107, 138, 0.12);

  --gold-light: #fff4a3;
  --gold-highlight: #ffe06a;
  --gold-main: #f5bd24;
  --gold-shadow: #b86d00;
  --gold-deep: #704000;

  --font-display: "Fraunces", Georgia, serif;
  --font-body: "Inter", -apple-system, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;

  --container: 1120px;
  --radius: 14px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

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

.wrap {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 28px;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--scatter-blue);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.eyebrow::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--haze-amber);
  display: inline-block;
}

/* ---------- Skip link ---------- */
.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--ink);
  color: var(--paper);
  padding: 10px 16px;
  z-index: 999;
  border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------- Masthead (title first) ---------- */
.masthead {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(180deg, rgba(10, 28, 37, 0.096), rgba(10, 28, 37, 0.11)),
    url("../style-img/kolkata-4.png") center / cover no-repeat;
  border-bottom: 1px solid var(--line);
}

.masthead::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, rgba(18, 36, 43, 0.42), rgba(44, 107, 138, 0.12) 55%, rgba(217, 126, 46, 0.2));
  pointer-events: none;
}

#particle-field {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.masthead-inner {
  position: relative;
  z-index: 2;
  width: min(100% - 32px, 882px);
  margin: 20px auto;
  padding: 16px 20px;
  text-align: center;
  background: rgba(255, 255, 255, 0);
  border: 1px solid rgba(255, 255, 255, 0.78);
  border-radius: 24px;
  box-shadow: 0 18px 50px rgba(7, 24, 32, 0.2);
  backdrop-filter: blur(1px);
}

.masthead.sub .masthead-inner {
  padding: 10px 28px 46px;
}

.masthead.sub h1 {
  font-size: clamp(1.9rem, 4.6vw, 2.9rem);
  letter-spacing: 0.03em;
}

.masthead.sub .theme-line {
  font-size: clamp(0.95rem, 1.8vw, 1.1rem);
}

.masthead-logos {
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: 500;
  gap: 10px;
  margin-bottom: 22px;
  font-family: var(--font-mono);
  font-size: 1rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgb(251, 251, 252);
}
.masthead-logos span.sep { color: var(--line-strong); }

.masthead h1 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2.6rem, 7vw, 5.2rem);
  letter-spacing: 0.1em;
  margin: 0 0 10px;
  line-height: 1;
  color: var(--gold-main);
  background: linear-gradient(
    165deg,
    var(--gold-light) 0%,
    var(--gold-highlight) 18%,
    var(--gold-main) 43%,
    var(--gold-shadow) 76%,
    var(--gold-deep) 100%
  );
  background-size: 180% 180%;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow:
    0 1px 0 rgba(255, 244, 163, 0.85),
    1px 2px 0 rgba(255, 215, 163, 0.85),
    2px 3px 0 rgba(255, 197, 163, 0.85),
    3px 5px 0 var(--gold-deep),
    4px 10px 2px rgba(42, 24, 0, 0.38);
  animation: gold-title-shine 7s ease-in-out infinite alternate;
}

.masthead h1 em {
  font-style: normal;
  color: inherit;
}

@keyframes gold-title-shine {
  from { background-position: 0% 35%; }
  to { background-position: 100% 65%; }
}

@media (prefers-reduced-motion: reduce) {
  .masthead h1 { animation: none; }
}

.masthead .full-name {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 900;
  letter-spacing: 0.04em;
  color: rgb(255, 255, 255);
  text-shadow: 2px 2px 2px rgba(0, 0, 0, 0.8);
  margin: 0 0 18px;
  /*text-shadow: 
    -1px -1px 0 #000000,  
     1px -1px 0 #000000,
    -1px  1px 0 #000000,
     1px  1px 0 #000000;*/
}

.masthead .theme-line {
  font-family: var(--font-display);
  font-style: italic;
  font-size: clamp(1.05rem, 2.4vw, 1.5rem);
  max-width: 760px;
  margin: 0 auto 22px;
  color: #dceff0;
  text-shadow: 0 2px 12px rgba(0, 0, 0, 0.42);
  line-height: 1.4;
}

.masthead-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 12px;
  font-family: var(--font-mono);
  font-size: 1rem;
  color: darkblue;
}

.masthead-meta .pill {
  border: 1px solid var(--line-strong);
  background: rgba(251, 250, 246, 0.82);
  backdrop-filter: blur(6px);
  padding: 7px 14px;
  border-radius: 999px;
}

.masthead-cta {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin-top: 34px;
  flex-wrap: wrap;
}

/* ---------- Horizontal nav (above the title) ---------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgb(255, 255, 254);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
}

.site-nav .wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  min-height: 44px;
  padding: 4px 28px;
}

.site-nav .nav-mark {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: rgba(246, 247, 251, 0.78);
  white-space: nowrap;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 0px;
  margin: 0;
  padding: 0;
  flex-wrap: wrap;
}

.nav-links > li { position: relative; }

.nav-links a {
  display: inline-block;
  text-decoration: none;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(251, 250, 246, 0.9);
  padding: 9px 9px;
  border-radius: 100px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  background: rgba(5, 76, 207, 0.836);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.16);
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  background: rgb(14, 6, 119);
  border-color: rgba(255, 255, 255, 0.48);
  color: var(--paper);
  transform: translateY(-1px);
}

.nav-links a[aria-current="page"] {
  color: var(--paper);
  background: rgba(217, 126, 46, 0.82);
  border-color: rgba(255, 220, 178, 0.7);
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.2);
}

.dropdown-menu {
  list-style: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%) translateY(-6px);
  min-width: 180px;
  margin: 0;
  padding: 8px 0;
  background: rgba(255, 255, 255, 0.98);
  border: 1px solid rgba(18, 36, 43, 0.13);
  border-radius: 12px;
  box-shadow: 0 14px 36px rgba(18, 36, 43, 0.14);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease;
  z-index: 60;
}

.dropdown:hover > .dropdown-menu,
.dropdown:focus-within > .dropdown-menu,
.dropdown > a[aria-expanded="true"] + .dropdown-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

.dropdown-menu a {
  display: block;
  width: 100%;
  padding: 8px 16px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--ink);
  background: transparent;
  border: none;
  border-radius: 0;
  box-shadow: none;
  transition: background 0.15s ease, color 0.15s ease;
}

.dropdown-menu a:hover,
.dropdown-menu a:focus-visible {
  background: rgba(5, 76, 207, 0.08);
  color: rgb(5, 76, 207);
  transform: none;
}

.dropdown > a span { font-size: 0.65rem; margin-left: 2px; }

.nav-toggle {
  display: none;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  background: rgb(255, 255, 255);
  border: 1px solid rgb(255, 255, 255);
  border-radius: 8px;
  padding: 8px 12px;
  color: var(--paper);
  cursor: pointer;
}

/* ---------- Buttons ---------- */
.btn {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  text-decoration: none;
  padding: 12px 22px;
  border-radius: 999px;
  border: 1px solid var(--ink);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: transform 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.btn-primary {
  background: var(--ink);
  color: var(--paper);
}
.btn-primary:hover { transform: translateY(-2px); background: var(--scatter-blue); border-color: var(--scatter-blue); }

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line-strong);
}
.btn-ghost:hover { transform: translateY(-2px); border-color: var(--ink); }

/* ---------- Sections ---------- */
section { padding: 72px 0; }
section.tight { padding: 48px 0; }

.section-head {
  max-width: 640px;
  margin-bottom: 40px;
}

.section-head h2 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.7rem, 3.4vw, 2.4rem);
  margin: 12px 0 0;
  color: var(--ink);
}

.section-head p {
  color: var(--ink-soft);
  font-size: 1.02rem;
  line-height: 1.6;
  margin-top: 12px;
}

/* ---------- Theme statement ---------- */
.theme-block {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 56px 0;
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: 48px;
  align-items: start;
}

.theme-block .theme-copy p {
  font-size: 1.05rem;
  line-height: 1.75;
  color: var(--ink-soft);
}

.theme-pillars {
  display: grid;
  gap: 14px;
}

.pillar {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
  background: var(--paper);
}

.pillar .pillar-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.pillar:nth-child(1) .pillar-label { color: var(--scatter-blue); }
.pillar:nth-child(2) .pillar-label { color: var(--haze-amber); }
.pillar:nth-child(3) .pillar-label { color: var(--clean-sage); }

.pillar p { margin: 6px 0 0; font-size: 0.94rem; color: var(--ink-soft); line-height: 1.5; }

/* ---------- Timeline / important dates ---------- */
.timeline {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.timeline-item {
  background: var(--paper);
  padding: 26px 20px;
  position: relative;
}

.timeline-item .idx {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-soft);
  opacity: 0.6;
}

.timeline-item .label {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--scatter-blue);
  margin-top: 10px;
}

.timeline-item .value {
  font-family: var(--font-display);
  font-size: 1.5rem;
  margin-top: 6px;
  color: var(--ink);
}

.timeline-item .value.struck {
  text-decoration: line-through;
  color: var(--ink-soft);
  font-size: 1.1rem;
  display: block;
}

.timeline-item .value.extended {
  color: var(--haze-amber);
  font-weight: 600;
  animation: flashExtended 1.6s ease-in-out infinite;
  display: block;
  font-size: 1.25rem;
  margin-top: 2px;
}

@keyframes flashExtended {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.45; }
}

@media (prefers-reduced-motion: reduce) {
  .timeline-item .value.extended { animation: none; }
}

/* ---------- Cards / grid ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.info-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px;
  background: var(--paper);
  text-decoration: none;
  color: var(--ink);
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.info-card:hover {
  border-color: var(--ink);
  transform: translateY(-4px);
  box-shadow: 0 14px 30px rgba(18, 36, 43, 0.08);
}

.info-card .card-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.info-card h3 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  margin: 0;
}

.info-card p { margin: 0; color: var(--ink-soft); font-size: 0.92rem; line-height: 1.55; }

.info-card .card-arrow {
  margin-top: auto;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--scatter-blue);
}

/* ---------- Host strip ---------- */
.host-strip {
  border-top: 1px solid var(--line);
  padding: 48px 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.host-strip h4 {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin: 0 0 10px;
}

.host-strip p {
  font-size: 1rem;
  line-height: 1.6;
  color: var(--ink);
  margin: 0;
}

.host-content {
  display: flex;
  align-items: center;
  gap: 22px;
}

.host-content .logo-container {
  flex: 0 0 auto;
  margin: 0;
  gap: 18px;
}

.host-content .logo-wrapper,
.host-content .logo-wrapper3,
.host-logo {
  width: 100px;
  height: 100px;
  flex: 0 0 auto;
}

.host-logo {
  object-fit: contain;
}

/* ---------- Partner strip ---------- */
.partner-strip {
  border-top: 1px solid var(--line);
  padding: 34px 0 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.partner-strip h2 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  margin: 10px 0 0;
}

.partner-link {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-decoration: none;
  transition: color 180ms ease, transform 180ms ease;
}

.partner-link img {
  width: 150px;
  height: 88px;
  object-fit: contain;
  border: 1px solid var(--line);
  background: #fff;
  padding: 8px;
}

.partner-link:hover,
.partner-link:focus-visible {
  color: var(--scatter-blue);
  transform: translateY(-2px);
}

/* ---------- Placeholder / "to be updated" blocks ---------- */
.pending {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius);
  padding: 30px 26px;
  background: repeating-linear-gradient(
    135deg,
    rgba(217, 126, 46, 0.04),
    rgba(217, 126, 46, 0.04) 10px,
    transparent 10px,
    transparent 20px
  );
}

.pending .eyebrow { color: var(--haze-amber); }
.pending .eyebrow::before { background: var(--scatter-blue); }

.pending h3 {
  font-family: var(--font-display);
  font-size: 1.4rem;
  margin: 10px 0 8px;
}

.pending p {
  color: var(--ink-soft);
  line-height: 1.6;
  max-width: 620px;
}

.pending ul {
  margin: 14px 0 0;
  padding-left: 18px;
  color: var(--ink-soft);
  line-height: 1.7;
}

.map-frame {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--sky-deep);
  box-shadow: 0 14px 30px rgba(18, 36, 43, 0.08);
}

.map-frame iframe {
  display: block;
  width: 100%;
  height: min(62vw, 640px);
  min-height: 500px;
}

.venue-intro {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 42px 0;
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(220px, 0.8fr);
  gap: 48px;
  align-items: center;
}

.venue-copy {
  display: flex;
  align-items: center;
  gap: 28px;
}

.venue-logo {
  width: 150px;
  height: 150px;
  object-fit: contain;
  flex: 0 0 auto;
}

.venue-copy h2 {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3.5vw, 2.8rem);
  line-height: 1.08;
  margin: 10px 0;
}

.venue-description {
  color: var(--ink-soft);
  line-height: 1.6;
  max-width: 560px;
  margin: 0 0 20px;
}

.venue-link {
  font-size: 0.72rem;
  padding: 11px 16px;
}

.venue-facts {
  border-left: 1px solid var(--line);
  padding-left: 30px;
}

.venue-facts h4 {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin: 0 0 8px;
}

.venue-facts h4:not(:first-child) {
  margin-top: 24px;
}

.venue-facts p {
  color: var(--ink);
  line-height: 1.6;
  margin: 0;
}

/* ---------- Table (committee / contact detail) ---------- */
.detail-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 10px;
}

.detail-table th,
.detail-table td {
  text-align: left;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
  font-size: 0.95rem;
}

.detail-table th {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  font-weight: 500;
}

/* ---------- Footer ---------- */
footer {
  border-top: 1px solid var(--line);
  background: var(--sky);
  padding: 52px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 36px;
}

.footer-grid h5 {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin: 0 0 12px;
}

.footer-grid p, .footer-grid a {
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--ink);
  text-decoration: none;
}

.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: 8px; }
.footer-grid a:hover { color: var(--scatter-blue); }

.footer-base {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--ink-soft);
}

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .theme-block { grid-template-columns: 1fr; }
  .timeline { grid-template-columns: 1fr 1fr; }
  .card-grid { grid-template-columns: 1fr; }
  .host-strip { grid-template-columns: 1fr; }
  .partner-strip { align-items: flex-start; flex-direction: column; }
  .footer-grid { grid-template-columns: 1fr; }
  .venue-intro { grid-template-columns: 1fr; gap: 28px; }
  .venue-facts { border-left: 0; border-top: 1px solid var(--line); padding: 24px 0 0; }

  .nav-toggle { display: inline-block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 54px;
    left: 0;
    right: 0;
    background: var(--ink);
    border-bottom: 1px solid rgba(255, 255, 255, 0.16);
    flex-direction: column;
    padding: 10px 20px 18px;
  }
  .nav-links.open { display: flex; }
  .nav-links > li { position: static; }
  .nav-links a { padding: 12px 4px; }
  .dropdown-menu {
    position: static;
    transform: none;
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    display: none;
    box-shadow: none;
    background: rgba(255, 255, 255, 0.06);
    border: 0;
    border-radius: 8px;
    padding: 4px 0;
    margin: 4px 0 6px 12px;
    min-width: auto;
  }
  .dropdown.open > .dropdown-menu,
  .dropdown:focus-within > .dropdown-menu { display: block; }
  .dropdown-menu a { color: var(--paper); padding: 8px 12px; }
  .dropdown-menu a:hover,
  .dropdown-menu a:focus-visible { background: rgba(255, 255, 255, 0.12); color: var(--paper); }
}

@media (max-width: 560px) {
  .timeline { grid-template-columns: 1fr; }
  .venue-copy { align-items: flex-start; flex-direction: column; gap: 18px; }
  .venue-logo { width: 120px; height: 120px; }
  .map-frame iframe { height: 500px; min-height: 0; }
  .host-content { align-items: flex-start; flex-direction: column; gap: 14px; }
}