:root {
  --primary: #081120;
  --secondary: #122B52;
  --accent: #D4A44A;
  --bg-main: #FAF8F3;
  --surface: #ffffff;
  --muted: #64748B;
  --border: rgba(18, 43, 82, 0.1);
  --line: rgba(18, 43, 82, 0.1);

  /* Legacy variable mapping for script.js compatibility */
  --blue: var(--accent);
  --soft: transparent;

  --font-body: 'Inter', system-ui, -apple-system, sans-serif;
  --font-heading: 'Playfair Display', serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--primary);
  background: var(--bg-main);
  font-family: var(--font-body);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
img {
  max-width: 100%;
  display: block;
}

/* --- CUSTOM SCROLLBAR --- */
::-webkit-scrollbar {
  width: 10px;
}
::-webkit-scrollbar-track {
  background: var(--bg-main);
}
::-webkit-scrollbar-thumb {
  background: rgba(18, 43, 82, 0.5); /* var(--secondary) with opacity */
  border-radius: 8px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent);
}

/* --- NAVIGATION --- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  transition: all 0.3s ease;
  padding: 16px clamp(20px, 5vw, 80px);
  background: rgba(248, 246, 242, 0.95);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(20px);
  box-shadow: 0 4px 20px rgba(8, 17, 32, 0.03);
}
.site-nav::-webkit-scrollbar { display: none; }
.site-nav a {
  flex: 0 0 auto;
  padding: 10px 16px;
  border-radius: 999px;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: all 0.2s ease;
}
.site-nav .brand {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  background: none;
  color: var(--primary);
  font-weight: 700;
  padding: 8px 16px 8px 0;
}
.site-nav a:hover:not(.brand) {
  color: var(--accent);
  background: transparent;
}

/* --- HERO SECTION --- */
.hero {
  min-height: 90vh;
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.7fr);
  gap: 60px;
  align-items: center;
  padding: 140px clamp(24px, 6vw, 100px) 100px;
  color: #fff;
  background:
    linear-gradient(135deg, rgba(8, 17, 32, 0.95), rgba(18, 43, 82, 0.85)),
    url("../assets/images/VVIT.png") center/cover fixed;
  position: relative;
  isolation: isolate;
}
.eyebrow,
.section-heading span {
  display: inline-flex;
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  font-family: var(--font-body);
  margin-bottom: 16px;
}
.hero h1 {
  font-family: var(--font-heading);
  max-width: 980px;
  margin: 0 0 24px;
  font-size: clamp(2.5rem, 5vw, 4.2rem);
  line-height: 1.15;
  letter-spacing: -0.01em;
  font-weight: 400;
}
.hero p {
  max-width: 760px;
  margin: 0 0 20px;
  color: rgba(255, 255, 255, 0.8);
  font-size: clamp(1.1rem, 1.5vw, 1.25rem);
  line-height: 1.8;
}
.hero .theme {
  color: var(--accent);
  font-weight: 500;
  letter-spacing: 0.02em;
}
.hero-panel {
  overflow: hidden;
  border-radius: 4px;
  background: rgba(8, 17, 32, 0.4);
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 30px 60px rgba(0,0,0,0.3);
}
.hero-panel img {
  width: 100%;
  height: 280px;
  object-fit: cover;
  filter: grayscale(20%) contrast(110%);
}
.hero-panel div {
  padding: 32px;
}
.hero-panel span {
  color: rgba(255,255,255,0.6);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.hero-panel strong {
  display: block;
  color: var(--accent);
  font-family: var(--font-heading);
  font-weight: 400;
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  line-height: 1.1;
  margin: 8px 0 16px;
}

/* --- PAGE HERO (SUBPAGES) --- */
.page-hero {
  position: relative;
  background: 
    linear-gradient(135deg, rgba(8, 17, 32, 0.92), rgba(18, 43, 82, 0.85)), 
    url("../assets/images/conference vvit.jpg") center/cover fixed;
  padding: 160px clamp(24px, 6vw, 100px) 100px;
  text-align: center;
  color: var(--surface);
  border-bottom: 4px solid var(--accent);
  isolation: isolate;
}
.page-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 100%, rgba(212, 164, 74, 0.15), transparent 60%);
  z-index: -1;
}
.page-hero h1 {
  font-family: var(--font-heading);
  font-size: clamp(2.5rem, 5vw, 4rem);
  margin: 0 0 16px;
  font-weight: 500;
}
.page-hero p {
  color: var(--accent);
  font-size: 1.1rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-weight: 600;
  margin: 0;
}

.breadcrumb {
  margin-bottom: 24px;
  font-family: var(--font-body);
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.7);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  font-weight: 600;
}
.breadcrumb a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}
.breadcrumb a:hover {
  color: var(--surface);
}
.breadcrumb span {
  margin: 0 12px;
  color: rgba(255, 255, 255, 0.3);
}

/* --- DATE STRIP (TIMELINE) --- */
.date-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  padding: 80px clamp(24px, 6vw, 100px);
  background: var(--surface);
  position: relative;
}
.date-strip::before {
  content: '';
  position: absolute;
  top: 50%;
  left: clamp(24px, 6vw, 100px);
  right: clamp(24px, 6vw, 100px);
  height: 1px;
  background: var(--line);
  z-index: 0;
}
.date-strip article {
  background: var(--surface);
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent);
  border-radius: 0;
  padding: 40px 32px;
  text-align: left;
  box-shadow: 0 10px 30px rgba(8, 17, 32, 0.02);
  transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.4s ease;
  position: relative;
  z-index: 1;
}
.date-strip article:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(8, 17, 32, 0.08);
}
.date-strip span {
  display: block;
  margin-bottom: 12px;
  color: var(--secondary);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}
.date-strip strong {
  font-family: var(--font-heading);
  color: var(--primary);
  font-size: 1.5rem;
  font-weight: 600;
  display: block;
}

/* --- GENERAL SECTIONS --- */
.section {
  padding: 100px clamp(24px, 6vw, 100px);
  scroll-margin-top: 60px;
  position: relative;
  overflow: hidden;
  z-index: 1;
}
.section-heading {
  max-width: 920px;
  margin-bottom: 48px;
}
.section-heading h2 {
  margin: 0;
  font-family: var(--font-heading);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 400;
  color: var(--primary);
  line-height: 1.15;
}
p {
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.8;
  margin-top: 0;
  margin-bottom: 1.5rem;
}

.content-grid,
.conference-layout,
.submission-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(300px, 0.7fr);
  gap: 40px;
  align-items: start;
}

/* --- ABOUT INSTITUTE (EDITORIAL STYLE) --- */
.about-vvit {
  background: var(--bg-main);
}
.campus-banner {
  position: relative;
  overflow: hidden;
  margin: 0 0 40px;
}
.campus-banner img {
  width: 100%;
  height: clamp(300px, 45vw, 600px);
  object-fit: cover;
  animation: imageSettle 1.2s ease both;
  filter: contrast(1.05);
}
.campus-banner figcaption {
  position: absolute;
  left: 0;
  bottom: 0;
  max-width: 600px;
  padding: 24px 40px;
  color: var(--primary);
  background: var(--surface);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1.25rem;
  border-top: 1px solid var(--line);
  border-right: 1px solid var(--line);
}
.institute-media-row {
  display: grid;
  grid-template-columns: minmax(300px, 0.8fr) minmax(0, 1fr);
  gap: 40px;
  align-items: stretch;
  margin-top: 40px;
}
.institute-media-row figure {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
}
.institute-media-row img {
  width: 100%;
  height: 100%;
  min-height: 340px;
  object-fit: cover;
  transition: transform .8s ease;
}
.institute-media-row figure:hover img,
.campus-banner:hover img {
  transform: scale(1.03);
}
@keyframes imageSettle {
  from { opacity: 0; transform: scale(1.03); }
  to { opacity: 1; transform: scale(1); }
}
.prose-card {
  background: transparent;
}
.prose-card.wide {
  margin-top: 40px;
}
.prose-card p {
  color: var(--primary);
}
.highlight-card, .theme-card {
  transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}
.highlight-card:hover, .theme-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(8, 17, 32, 0.08);
}
.submission-card {
  transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}
.submission-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(8, 17, 32, 0.15);
}
.highlight-card {
  background: var(--primary);
  color: var(--surface);
  padding: 48px;
}
.highlight-card h3 {
  font-family: var(--font-heading);
  color: var(--accent);
  font-size: 1.75rem;
  font-weight: 400;
  margin: 0 0 24px;
}
.highlight-card ul {
  margin-bottom: 0;
  padding-left: 0;
  list-style: none;
}
.highlight-card li {
  color: rgba(255,255,255,0.8);
  border-bottom: 1px solid rgba(255,255,255,0.1);
  padding: 16px 0;
  line-height: 1.6;
}
.highlight-card li:last-child {
  border-bottom: none;
}

/* --- CONFERENCE SECTION --- */
.conference {
  background: #F0F4F8;
}
.theme-card {
  background: var(--surface);
  border-left: 4px solid var(--secondary);
  padding: 48px;
  box-shadow: 0 20px 40px rgba(8, 17, 32, 0.04);
}
.theme-card h3 {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 400;
  color: var(--primary);
  line-height: 1.3;
  margin: 0 0 20px;
}
.theme-card p {
  margin-bottom: 0;
}

/* --- CALL FOR PAPERS (TRACKS) --- */
.tracks-section {
  background: var(--surface);
}
.tracks-grid {
  counter-reset: track-counter;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
  margin-top: 40px;
}
.track {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--line);
  border-left: 4px solid var(--secondary);
  padding: 40px;
  position: relative;
  transition: all 0.3s ease;
  box-shadow: 0 10px 30px rgba(0,0,0,0.02);
}
.track:hover {
  border-left-color: var(--accent);
  box-shadow: 0 20px 40px rgba(8, 17, 32, 0.08);
  transform: translateY(-8px);
}
.track::before {
  counter-increment: track-counter;
  content: counter(track-counter, decimal-leading-zero);
  display: block;
  font-family: var(--font-heading);
  font-size: 3rem;
  color: rgba(18, 43, 82, 0.1);
  line-height: 1;
  margin-bottom: 24px;
  transition: color 0.3s ease;
}
.track:hover::before {
  color: var(--accent);
}
.track h3 {
  margin: 0 0 20px;
  color: var(--primary);
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 600;
}
.track ul {
  display: flex;
  flex-direction: column;
  margin: 0;
  padding: 0;
  list-style: none;
}
.track li {
  padding: 10px 0 10px 20px;
  color: var(--muted);
  border-bottom: 1px dashed var(--line);
  font-size: 1rem;
  position: relative;
}
.track li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--accent);
}
.track li:last-child {
  border-bottom: none;
}

/* --- PAPER SUBMISSION --- */
.paper-submission {
  background: var(--bg-main);
}
.submission-card {
  background: var(--primary);
  color: var(--surface);
  padding: 48px;
}
.submission-card h3,
.prose-card h3 {
  margin: 0 0 24px;
  font-size: 1.75rem;
  font-family: var(--font-heading);
  color: var(--primary);
}
.submission-card h3 {
  color: var(--accent);
}
.submission-card ul {
  margin: 0;
  padding-left: 20px;
}
.submission-card li {
  color: rgba(255,255,255,0.8);
  border-bottom: 1px solid rgba(255,255,255,0.1);
  padding: 12px 0;
}
.submission-card li:last-child {
  border-bottom: none;
}
.submission-actions {
  display: grid;
  gap: 16px;
  margin-top: 40px;
}
.submission-actions a {
  display: inline-flex;
  justify-content: center;
  padding: 16px 24px;
  color: var(--surface);
  background: var(--secondary);
  border: 1px solid var(--secondary);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  transition: all 0.3s ease;
}
.submission-actions a:hover {
  background: var(--primary);
  border-color: var(--primary);
}
.submission-actions a:nth-child(2),
.submission-actions a:nth-child(3) {
  background: transparent;
  border-color: rgba(255,255,255,0.2);
}
.submission-actions a:nth-child(2):hover,
.submission-actions a:nth-child(3):hover {
  background: var(--accent);
  border-color: var(--accent);
}

/* --- COMMITTEE SECTION --- */
.committee-section {
  color: #fff;
  background: var(--primary);
  position: relative;
  isolation: isolate;
}
.committee-section .section-heading span,
.committee-section .section-heading h2 {
  color: var(--surface);
}
.committee-section p {
  color: rgba(255,255,255,0.7);
}
.committee-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 32px;
}
.committee-row {
  background: var(--secondary);
  border: 1px solid rgba(255, 255, 255, 0.05);
  transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}
.committee-row:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(0,0,0,0.4);
  border-color: rgba(212, 164, 74, 0.3);
  background: #17335e;
}
.committee-row h3 {
  margin: 0;
  padding: 20px 24px;
  font-family: var(--font-heading);
  background: rgba(255,255,255,0.02);
  color: var(--accent);
  font-size: 1.5rem;
  font-weight: 400;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.committee-row ul {
  margin: 0;
  padding: 24px;
  list-style: none;
}
.committee-row li {
  margin: 0;
  padding: 8px 0;
  color: rgba(255,255,255,0.7);
  line-height: 1.6;
}

/* --- REGISTRATION --- */
.registration {
  background: var(--primary);
}
.registration .section-heading span,
.registration .section-heading h2 {
  color: var(--surface);
}
.fee-card {
  max-width: 900px;
  margin: 0 auto;
  background: var(--secondary);
  border: 1px solid rgba(212, 164, 74, 0.2);
  border-top: 4px solid var(--accent);
  padding: clamp(32px, 5vw, 64px);
  box-shadow: 0 30px 60px rgba(0,0,0,0.3);
}
table {
  width: 100%;
  border-collapse: collapse;
}
th,
td {
  padding: 28px clamp(16px, 4vw, 32px);
  border-bottom: 1px dashed rgba(255, 255, 255, 0.1);
  text-align: left;
}
th {
  background: transparent;
  color: rgba(255, 255, 255, 0.6);
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.2em;
}
th:last-child {
  text-align: right;
}
td {
  color: var(--surface);
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: 0.02em;
}
td:last-child {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  color: var(--accent);
  text-align: right;
  font-weight: 500;
}
tr:last-child td { border-bottom: none; }

/* --- CONTACT --- */
.contact {
  background: var(--primary);
}
.contact .section-heading span,
.contact .section-heading h2 {
  color: var(--surface);
}
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
}
.contact-grid article {
  background: var(--secondary);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-left: 4px solid var(--secondary);
  padding: 48px 40px;
  text-align: left;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
  transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}
.contact-grid article:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
  border-left-color: var(--accent);
  background: #17335e;
}
.contact-grid h3 {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  color: var(--surface);
  font-size: 1.6rem;
  font-weight: 600;
}
.contact-grid p {
  color: rgba(255, 255, 255, 0.6);
  font-size: 1rem;
  margin-bottom: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid rgba(212, 164, 74, 0.2);
}
.contact-grid a,
.contact-grid span {
  display: block;
  margin-top: 12px;
  color: var(--accent);
  font-family: var(--font-body);
  font-size: 1.05rem;
  font-weight: 500;
  text-decoration: none;
  overflow-wrap: anywhere;
  transition: all 0.3s ease;
}
.contact-grid a:hover {
  color: var(--surface);
  transform: translateX(4px);
}

.inview {
  animation: riseIn 0.8s cubic-bezier(0.16, 1, 0.3, 1) both;
}
@keyframes riseIn {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: none; }
}

/* --- RESPONSIVE --- */
@media (max-width: 1024px) {
  .hero,
  .content-grid,
  .conference-layout,
  .submission-layout,
  .institute-media-row,
  .contact-grid {
    grid-template-columns: 1fr;
  }
  .hero {
    text-align: center;
    padding-top: 140px;
  }
  .date-strip {
    grid-template-columns: repeat(2, 1fr);
  }
  .date-strip::before { display: none; }
}
@media (max-width: 768px) {
  .hero-panel {
    min-height: 240px;
  }
  .hero-panel img {
    height: 200px;
  }
  .campus-banner figcaption {
    position: static;
    max-width: none;
    border-top: none;
  }
  .date-strip {
    grid-template-columns: 1fr;
  }
  .section {
    padding: 80px 20px;
  }
}