/* REACH-AI 2026 Workshop Site */

:root {
  --color-navy: #0f2744;
  --color-navy-light: #1a3a5c;
  --color-teal: #2a7a78;
  --color-teal-light: #3d9a97;
  --color-bg: #f7f8fa;
  --color-bg-alt: #eef1f5;
  --color-text: #1e2a3a;
  --color-text-muted: #5a6a7e;
  --color-border: #d4dae3;
  --color-white: #ffffff;
  --font-serif: 'Source Serif 4', Georgia, 'Times New Roman', serif;
  --font-sans: 'Source Sans 3', system-ui, -apple-system, sans-serif;
  --max-width: 1100px;
  --header-height: 4rem;
  --radius: 4px;
  --shadow-sm: 0 1px 3px rgba(15, 39, 68, 0.08);
  --shadow-md: 0 4px 12px rgba(15, 39, 68, 0.1);
  --transition: 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-bg);
  opacity: 0;
  transition: opacity 0.4s ease;
}

#site-header,
.hero,
.page-hero {
  flex-shrink: 0;
}

main {
  flex: 1;
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

body.is-loaded {
  opacity: 1;
}

body.nav-open {
  overflow: hidden;
}

img {
  max-width: 100%;
  height: auto;
}

a {
  color: var(--color-teal);
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-teal-light);
}

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  color: var(--color-navy);
  line-height: 1.25;
  margin-top: 0;
}

h1 {
  font-size: clamp(2.25rem, 5vw, 3.25rem);
  font-weight: 600;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

p {
  margin-top: 0;
  margin-bottom: 1rem;
}

ul, ol {
  margin-top: 0;
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.35rem;
}

.tbd {
  color: var(--color-text-muted);
  font-style: italic;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-height);
  gap: 1rem;
}

.site-logo {
  display: flex;
  align-items: baseline;
  gap: 0.35rem;
  text-decoration: none;
  flex-shrink: 0;
}

.logo-mark {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-navy);
  letter-spacing: 0.04em;
}

.logo-year {
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-teal);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  width: 1.5rem;
  height: 2px;
  background: var(--color-navy);
  transition: transform var(--transition), opacity var(--transition);
}

.site-nav .nav-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.25rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-nav a {
  display: inline-block;
  padding: 0.35rem 0;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  position: relative;
}

.site-nav a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--color-teal);
  transition: width var(--transition);
}

.site-nav a:hover::after,
.site-nav a.is-active::after {
  width: 100%;
}

.site-nav a.is-active {
  color: var(--color-navy);
  font-weight: 600;
}

/* Hero */
.hero {
  background: linear-gradient(165deg, var(--color-navy) 0%, var(--color-navy-light) 55%, #1e4d6b 100%);
  color: var(--color-white);
  padding: 4rem 1.5rem 4.5rem;
  text-align: center;
}

.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.hero-brand {
  font-family: var(--font-serif);
  font-size: clamp(2.75rem, 7vw, 4.5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin: 0 0 0.75rem;
  color: var(--color-white);
}

.hero-subtitle {
  font-family: var(--font-serif);
  font-size: clamp(1.1rem, 2.5vw, 1.45rem);
  font-weight: 400;
  font-style: italic;
  opacity: 0.92;
  max-width: 42rem;
  margin: 0 auto 1.25rem;
  line-height: 1.45;
}

.hero-meta {
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  opacity: 0.85;
  margin: 0;
}

.hero-meta span {
  display: inline-block;
  margin: 0 0.5rem;
  opacity: 0.5;
}

/* Page layout */
.page-hero {
  background: var(--color-bg-alt);
  border-bottom: 1px solid var(--color-border);
  padding: 2.5rem 1.5rem;
  text-align: center;
}

.page-hero h1 {
  margin-bottom: 0.5rem;
}

.page-hero .page-meta {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin: 0;
}

.content-section {
  margin-bottom: 2.5rem;
}

.content-section:last-child {
  margin-bottom: 0;
}

/* CTA buttons */
.cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 2rem;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius);
  transition: background var(--transition), color var(--transition), border-color var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--color-teal);
  color: var(--color-white);
  border-color: var(--color-teal);
}

.btn-primary:hover {
  background: var(--color-teal-light);
  border-color: var(--color-teal-light);
  color: var(--color-white);
}

.btn-secondary {
  background: transparent;
  color: var(--color-navy);
  border-color: var(--color-navy);
}

.btn-secondary:hover {
  background: var(--color-navy);
  color: var(--color-white);
}

/* Topic groups */
.topic-group {
  margin-bottom: 1.75rem;
}

.topic-group h3 {
  color: var(--color-teal);
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.5rem;
}

/* Dates table */
.dates-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.dates-list li {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem 1rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--color-border);
}

.dates-list li:last-child {
  border-bottom: none;
}

.dates-list .date-label {
  font-weight: 600;
  color: var(--color-navy);
}

.dates-list .date-value {
  color: var(--color-text-muted);
}

/* Schedule table */
.schedule-table-wrapper {
  overflow-x: auto;
  margin: 1.5rem 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-white);
  box-shadow: var(--shadow-sm);
}

.schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.schedule-table th,
.schedule-table td {
  padding: 0.85rem 1.25rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.schedule-table th {
  background: var(--color-bg-alt);
  font-weight: 600;
  color: var(--color-navy);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.schedule-table tr:last-child td {
  border-bottom: none;
}

.schedule-table .time-col {
  white-space: nowrap;
  font-weight: 600;
  color: var(--color-teal);
  width: 8rem;
}

.schedule-table .session-break td {
  background: var(--color-bg-alt);
  font-style: italic;
  color: var(--color-text-muted);
}

/* Keynote cards */
.keynote-list {
  display: grid;
  gap: 2rem;
}

.keynote-card {
  padding: 1.75rem;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.keynote-card .keynote-number {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-teal);
  margin-bottom: 0.5rem;
}

.keynote-card .keynote-title {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  margin-bottom: 1rem;
}

.keynote-card .keynote-speaker {
  font-weight: 600;
  color: var(--color-navy);
}

.keynote-card .keynote-affiliation {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.keynote-card .keynote-bio {
  margin-top: 1rem;
  font-size: 0.95rem;
}

/* Organizer cards */
.organizer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.organizer-card {
  padding: 1.5rem;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.organizer-card .organizer-name {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-navy);
  margin: 0 0 0.25rem;
}

.organizer-card .organizer-role {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-teal);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.5rem;
}

.organizer-card .organizer-affiliation {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin-bottom: 0.75rem;
}

.organizer-card ul {
  font-size: 0.9rem;
  margin-bottom: 0;
  padding-left: 1.25rem;
}

/* FAQ */
.faq-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.faq-item {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--color-border);
}

.faq-item:first-child {
  padding-top: 0;
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-question {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-navy);
  margin: 0 0 0.75rem;
}

.faq-answer {
  margin: 0;
}

/* Contact */
.contact-card {
  padding: 1.75rem;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  max-width: 32rem;
}

.contact-card .contact-name {
  font-weight: 600;
  color: var(--color-navy);
  font-size: 1.1rem;
}

.contact-card .contact-role {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin-bottom: 0.75rem;
}

/* Notice box */
.notice-box {
  padding: 1.25rem 1.5rem;
  background: var(--color-bg-alt);
  border-left: 4px solid var(--color-teal);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.5rem 0;
}

.notice-box p:last-child {
  margin-bottom: 0;
}

/* Footer */
#site-footer {
  flex-shrink: 0;
}

.site-footer {
  background: var(--color-navy);
  color: rgba(255, 255, 255, 0.85);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 1.5rem 2rem;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1.5fr;
  gap: 2rem;
}

.footer-title {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-white);
  margin: 0 0 0.5rem;
}

.footer-subtitle {
  font-size: 0.9rem;
  opacity: 0.8;
  margin: 0 0 0.75rem;
  line-height: 1.5;
}

.footer-meta {
  font-size: 0.85rem;
  opacity: 0.65;
  margin: 0;
}

.footer-heading {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-white);
  margin: 0 0 0.75rem;
}

.footer-links ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: var(--color-white);
}

.footer-links li {
  margin-bottom: 0.4rem;
}

.footer-ack {
  font-size: 0.85rem;
  opacity: 0.75;
  line-height: 1.55;
}

.footer-ack p:last-child {
  margin-bottom: 0;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding: 1rem 1.5rem;
  text-align: center;
}

.footer-bottom p {
  margin: 0;
  font-size: 0.8rem;
  opacity: 0.55;
}

.partial-error {
  padding: 1rem 1.5rem;
  background: #fff3cd;
  color: #664d03;
  font-size: 0.9rem;
  margin: 0;
}

/* Responsive */
@media (max-width: 900px) {
  .footer-inner {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .site-nav.is-open {
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
  }

  .site-nav .nav-list {
    flex-direction: column;
    padding: 1rem 1.5rem 1.5rem;
    gap: 0;
  }

  .site-nav a {
    display: block;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--color-border);
  }

  .site-nav li:last-child a {
    border-bottom: none;
  }

  .hero {
    padding: 3rem 1.25rem 3.5rem;
  }

  .dates-list li {
    flex-direction: column;
    gap: 0.25rem;
  }

  .schedule-table th,
  .schedule-table td {
    padding: 0.65rem 0.85rem;
    font-size: 0.875rem;
  }
}