/* ============================================================
   SEFI 2027 — Shared Stylesheet
============================================================ */
@import url('https://fonts.googleapis.com/css2?family=Source+Sans+3:ital,wght@0,300;0,400;0,500;0,600;0,700;1,400&family=Source+Serif+4:ital,opsz,wght@0,8..60,300;0,8..60,400;0,8..60,600;0,8..60,700;1,8..60,400&display=swap');

/* ============================================================
   DESIGN TOKENS
============================================================ */
:root {
  --sefi-blue:      #0077FF;
  --brand-violet:   #440099;
  --dark-violet:    #24125E;
  --electric-violet:#7000FF;
  --powder-violet:  #A78CFA;
  --pale-violet:    #C6BBFF;
  --wave-white:     #F8F8F9;
  --midnight-black: #131E29;
  --coral:          #E7004C;
  --aqua:           #00BBCC;

  --grad-brand: linear-gradient(135deg, var(--brand-violet) 0%, var(--sefi-blue) 100%);
  --grad-hero:  linear-gradient(160deg, rgba(36,18,94,0.88) 0%, rgba(0,119,255,0.55) 100%);

  --font-sans:  'Source Sans 3', system-ui, sans-serif;
  --font-serif: 'Source Serif 4', Georgia, serif;

  --nav-h: 68px;
  --sub-nav-h: 48px; /* sub-nav bar height when open (min-height on .sub-nav-inner) */
  --max-w: 1200px;
  --radius: 4px;
}

/* ============================================================
   RESET & BASE
============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-sans);
  background: var(--wave-white);
  color: var(--midnight-black);
  line-height: 1.6;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }

/* ============================================================
   UTILITY
============================================================ */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 2rem; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); }
.tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0.25em 0.8em;
  border-radius: 2px;
  background: var(--grad-brand);
  color: #fff;
  margin-bottom: 0.75rem;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius);
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform 0.2s, box-shadow 0.2s, background 0.2s;
  text-decoration: none;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 6px 24px rgba(0,0,0,0.18); }
.btn-primary { background: var(--grad-brand); color: #fff; }
.btn-outline { background: transparent; border-color: currentColor; color: inherit; }
.btn-outline:hover { background: rgba(0,0,0,0.05); }
.divider {
  width: 48px; height: 4px;
  background: var(--grad-brand);
  border-radius: 2px;
  margin: 1rem 0 1.5rem;
}

/* ============================================================
   NAVIGATION
============================================================ */
#site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  z-index: 100;
  display: flex;
  align-items: center;
  padding: 0 2rem;
  transition: background 0.4s, box-shadow 0.4s;
}
#site-nav.scrolled,
body.inner-page #site-nav {
  background: rgba(20,12,48,0.97);
  backdrop-filter: blur(12px);
  box-shadow: 0 2px 24px rgba(0,0,0,0.3);
}
.nav-inner {
  max-width: var(--max-w);
  width: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 2rem;
}
.nav-logo { display: flex; align-items: center; gap: 1rem; flex-shrink: 0; }
.nav-logo img { width: auto; }
.nav-sep { width: 1px; height: 28px; background: rgba(255,255,255,0.25); }
.nav-logo-pair { display: flex; align-items: center; gap: 0.4rem; }
.nav-wordmark {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  text-decoration: none;
}
.nav-wordmark span {
  font-size: 0.6rem;
  font-weight: 700;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.85);
  white-space: nowrap;
}
.nav-links {
  display: flex;
  gap: 0;
  list-style: none;
  flex: 1;
}
.nav-links > li { position: relative; }
.nav-links > li > a {
  display: block;
  color: rgba(255,255,255,0.82);
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  letter-spacing: 0.01em;
  white-space: nowrap;
  transition: color 0.2s;
  position: relative;
}
.nav-links > li > a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 1rem;
  right: 1rem;
  height: 2px;
  background: var(--powder-violet);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s cubic-bezier(0.22,1,0.36,1);
}
.nav-links > li > a:hover { color: #fff; }
.nav-links > li > a:hover::after { transform: scaleX(1); }
.nav-links > li > a.active { color: var(--powder-violet); }
.nav-links > li > a.active::after {
  transform: scaleX(1);
  background: var(--powder-violet);
}

/* Sub-nav bar */
#sub-nav {
  position: fixed;
  top: var(--nav-h);
  left: 0; right: 0;
  z-index: 99;
  background: rgba(12,6,36,0.97);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(167,140,250,0.18);
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.35s cubic-bezier(0.22,1,0.36,1), opacity 0.3s;
  opacity: 0;
}
#sub-nav.open {
  max-height: 120px;
  opacity: 1;
}
.sub-nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0.4rem 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  align-items: center;
  min-height: 48px;
  overflow: hidden;
  scrollbar-width: none;
  -ms-overflow-style: none;
}
.sub-nav-inner::-webkit-scrollbar { display: none; }
.sub-nav-inner a {
  color: rgba(255,255,255,0.7);
  font-size: 0.76rem;
  font-weight: 400;
  padding: 0.4rem 0.65rem;
  white-space: nowrap;
  transition: color 0.2s;
  border-right: 1px solid rgba(255,255,255,0.08);
}
.sub-nav-inner a:first-child { padding-left: 0; }
.sub-nav-inner a:hover { color: var(--powder-violet); }
.sub-nav-inner a.active { color: var(--powder-violet); }

/* Simple mode toggle */
.simple-toggle {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-shrink: 0;
  cursor: pointer;
  padding: 0.4rem 0.8rem;
  border-radius: 24px;
  border: 1.5px solid rgba(255,255,255,0.35);
  background: transparent;
  color: rgba(255,255,255,0.85);
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  transition: all 0.2s;
}
.simple-toggle:hover { border-color: rgba(255,255,255,0.7); color: #fff; }
.toggle-track {
  width: 32px; height: 18px;
  background: rgba(255,255,255,0.2);
  border-radius: 9px;
  position: relative;
  transition: background 0.2s;
}
.toggle-thumb {
  position: absolute;
  top: 2px; left: 2px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: #fff;
  transition: transform 0.2s;
}

/* Simple mode banner */
.simple-banner {
  display: none;
  background: var(--sefi-blue);
  color: #fff;
  text-align: center;
  padding: 0.6rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  position: fixed;
  top: var(--nav-h);
  left: 0;
  right: 0;
  z-index: 99;
}

/* ============================================================
   INNER PAGE BANNER
============================================================ */
.page-banner {
  background: linear-gradient(160deg, var(--dark-violet) 0%, var(--brand-violet) 60%, var(--sefi-blue) 100%);
  color: #fff;
  padding: calc(var(--nav-h) + 4rem) 0 3.5rem;
  position: relative;
  overflow: hidden;
}
.page-banner::after {
  content: '';
  position: absolute;
  inset: 0;
  background: url('SEFI_assets/photos/Medium-34051.jpg') center / cover no-repeat;
  opacity: 0.08;
  pointer-events: none;
}
.page-banner-inner {
  position: relative;
  z-index: 1;
}
.page-banner .tag {
  background: rgba(255,255,255,0.15);
  color: var(--pale-violet);
}
.page-banner h1 {
  font-family: var(--font-serif);
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}
.page-banner p {
  font-size: 1.1rem;
  opacity: 0.8;
  max-width: 560px;
  font-style: italic;
  font-family: var(--font-serif);
}

/* ============================================================
   SECTION FOUNDATIONS
============================================================ */
section { position: relative; }
.section-light { background: var(--wave-white); }
.section-dark { background: var(--dark-violet); color: #fff; }
.section-mid { background: #f0ecff; }
.section-pad { padding: 6rem 0; }
.section-head { margin-bottom: 3rem; }
.section-head h2 {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.01em;
  text-wrap: pretty;
}
.section-head p {
  font-size: 1.05rem;
  max-width: 600px;
  opacity: 0.8;
  margin-top: 0.75rem;
  text-wrap: pretty;
}

/* ============================================================
   SCROLL REVEAL
============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: none; }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }


/* ============================================================
   PARTNER STRIP
============================================================ */
#partner-strip {
  background: #fff;
  border-top: 1px solid #e8e4f4;
  border-bottom: 1px solid #e8e4f4;
  padding: 2rem 0;
}
.partner-strip-inner {
  display: flex;
  align-items: center;
  gap: 0;
  justify-content: center;
  flex-wrap: wrap;
}
.partner-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(0,0,0,0.35);
  margin-right: 2rem;
  white-space: nowrap;
}
.partner-logos { display: flex; align-items: center; gap: 2.5rem; flex-wrap: wrap; }
.partner-logos img { height: 28px; width: auto; object-fit: contain; filter: grayscale(1); opacity: 0.5; transition: filter 0.2s, opacity 0.2s; }
.partner-logos img:hover { filter: grayscale(0); opacity: 1; }

/* ============================================================
   ABOUT
============================================================ */
#about .about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}
.about-photo { position: relative; border-radius: 6px; overflow: hidden; }
.about-photo img { width: 100%; height: 460px; object-fit: cover; border-radius: 6px; }
.about-photo-badge {
  position: absolute;
  bottom: 1.5rem; left: 1.5rem;
  background: var(--grad-brand);
  color: #fff;
  padding: 0.6rem 1rem;
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 600;
}
.about-text h2 { font-family: var(--font-serif); font-size: clamp(1.75rem, 3.5vw, 2.5rem); font-weight: 700; line-height: 1.2; margin-bottom: 0.5rem; }
.about-text p { font-size: 1rem; opacity: 0.8; margin-top: 0.75rem; text-wrap: pretty; }
.about-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; margin-top: 2.5rem; }
.stat { text-align: center; }
.stat-num {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  font-weight: 700;
  background: var(--grad-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
}
.stat-label { font-size: 0.8rem; font-weight: 600; opacity: 0.65; margin-top: 0.25rem; letter-spacing: 0.04em; }

/* ============================================================
   THEMES
============================================================ */
#themes { background: var(--dark-violet); color: #fff; }
.themes-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.theme-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 6px;
  padding: 2rem;
  transition: background 0.2s, transform 0.2s;
}
.theme-card:hover { background: rgba(255,255,255,0.1); transform: translateY(-4px); }
.theme-icon {
  width: 40px; height: 40px;
  border-radius: 8px;
  background: var(--grad-brand);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 1rem;
  font-size: 1.2rem;
}
.theme-card h3 { font-family: var(--font-serif); font-size: 1.1rem; font-weight: 600; margin-bottom: 0.5rem; }
.theme-card p { font-size: 0.875rem; opacity: 0.7; text-wrap: pretty; }

/* ============================================================
   KEYNOTE SPEAKERS
============================================================ */
#speakers { background: var(--wave-white); }
.speakers-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.speaker-card {
  border-radius: 6px;
  overflow: hidden;
  background: #fff;
  box-shadow: 0 2px 24px rgba(68,0,153,0.08);
  transition: transform 0.2s, box-shadow 0.2s;
}
.speaker-card:hover { transform: translateY(-6px); box-shadow: 0 12px 40px rgba(68,0,153,0.14); }
.speaker-photo {
  height: 280px;
  background: linear-gradient(135deg, var(--dark-violet) 0%, var(--sefi-blue) 100%);
  display: flex; align-items: center; justify-content: center;
  position: relative; overflow: hidden;
}
.speaker-placeholder { font-size: 4rem; opacity: 0.3; }
.speaker-placeholder-text {
  position: absolute;
  bottom: 1rem; left: 1rem; right: 1rem;
  font-size: 0.7rem;
  font-family: monospace;
  color: rgba(255,255,255,0.4);
  text-align: center;
}
.speaker-info { padding: 1.5rem; }
.speaker-info h3 { font-family: var(--font-serif); font-size: 1.15rem; font-weight: 600; margin-bottom: 0.25rem; }
.speaker-affil { font-size: 0.8rem; opacity: 0.6; }
.speaker-topic { font-size: 0.875rem; margin-top: 0.75rem; font-style: italic; opacity: 0.75; }
.speaker-tba {
  text-align: center;
  padding: 3rem;
  background: #f0ecff;
  border-radius: 6px;
  grid-column: 1 / -1;
  font-size: 0.95rem;
  opacity: 0.7;
}

/* ============================================================
   CALL FOR PAPERS
============================================================ */
#cfp {
  background: linear-gradient(160deg, var(--brand-violet) 0%, #1a00cc 50%, var(--sefi-blue) 100%);
  color: #fff;
}
.cfp-inner { display: grid; grid-template-columns: 1fr 1fr; gap: 5rem; align-items: start; }
.cfp-text h2 { font-family: var(--font-serif); font-size: clamp(2rem, 4vw, 3rem); font-weight: 700; line-height: 1.2; }
.cfp-text p { margin-top: 1rem; opacity: 0.85; text-wrap: pretty; }
.cfp-dates { display: flex; flex-direction: column; gap: 0; margin-top: 2rem; }
.cfp-date-item {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
  padding: 1.25rem 0;
  border-bottom: 1px solid rgba(255,255,255,0.12);
}
.cfp-date-item:last-child { border-bottom: none; }
.cfp-date-dot { width: 10px; height: 10px; border-radius: 50%; background: var(--pale-violet); flex-shrink: 0; margin-top: 0.35rem; }
.cfp-date-label { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--pale-violet); }
.cfp-date-val { font-size: 1rem; font-weight: 600; margin-top: 0.1rem; }
.cfp-cta-block { padding-top: 1rem; }
.cfp-cta-block h3 { font-family: var(--font-serif); font-size: 1.5rem; font-weight: 600; margin-bottom: 1rem; }
.cfp-tracks { list-style: none; display: flex; flex-direction: column; gap: 0.5rem; margin-bottom: 2rem; }
.cfp-tracks li { display: flex; align-items: center; gap: 0.75rem; font-size: 0.9rem; opacity: 0.85; }
.cfp-tracks li::before { content: ''; width: 6px; height: 6px; border-radius: 50%; background: var(--powder-violet); flex-shrink: 0; }

/* ============================================================
   PROGRAMME
============================================================ */
#programme { background: #f0ecff; }
.programme-days { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; margin-bottom: 2.5rem; }
.day-card {
  background: #fff;
  border-radius: 6px;
  padding: 1.5rem;
  border-top: 3px solid transparent;
  box-shadow: 0 2px 16px rgba(68,0,153,0.06);
}
.day-card:nth-child(1) { border-top-color: var(--brand-violet); }
.day-card:nth-child(2) { border-top-color: var(--sefi-blue); }
.day-card:nth-child(3) { border-top-color: var(--electric-violet); }
.day-card:nth-child(4) { border-top-color: var(--aqua); }
.day-card .day-label { font-size: 0.7rem; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; opacity: 0.5; margin-bottom: 0.5rem; }
.day-card .day-date { font-family: var(--font-serif); font-size: 1.2rem; font-weight: 700; margin-bottom: 1rem; }
.day-card ul { list-style: none; display: flex; flex-direction: column; gap: 0.5rem; }
.day-card li { font-size: 0.8rem; opacity: 0.7; display: flex; gap: 0.5rem; align-items: flex-start; }
.day-card li::before { content: '–'; flex-shrink: 0; opacity: 0.5; }

/* ============================================================
   SOCIAL PROOF
============================================================ */
#social-proof { background: var(--brand-violet); color: #fff; padding: 3rem 0; }
.proof-inner { display: flex; justify-content: space-around; flex-wrap: wrap; gap: 2rem; text-align: center; }
.proof-num { font-family: var(--font-serif); font-size: 3rem; font-weight: 700; line-height: 1; }
.proof-label { font-size: 0.8rem; opacity: 0.7; margin-top: 0.3rem; letter-spacing: 0.06em; }

/* ============================================================
   VENUE
============================================================ */
#venue { background: var(--wave-white); }
.venue-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 4rem; align-items: start; }
.venue-photos { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.venue-photos img { border-radius: 4px; object-fit: cover; width: 100%; }
.venue-photos img:first-child { grid-column: 1 / -1; height: 260px; }
.venue-photos img:not(:first-child) { height: 170px; }
.venue-info h2 { font-family: var(--font-serif); font-size: clamp(1.75rem, 3.5vw, 2.5rem); font-weight: 700; line-height: 1.2; }
.venue-info p { margin-top: 0.75rem; opacity: 0.8; text-wrap: pretty; }
.venue-facts { margin-top: 2rem; display: flex; flex-direction: column; gap: 1rem; }
.venue-fact { display: flex; gap: 1rem; align-items: flex-start; }
.venue-fact-icon { width: 36px; height: 36px; border-radius: 50%; background: #f0ecff; display: flex; align-items: center; justify-content: center; flex-shrink: 0; font-size: 1rem; }
.venue-fact-text strong { display: block; font-size: 0.875rem; font-weight: 700; color: var(--brand-violet); }
.venue-fact-text span { font-size: 0.875rem; opacity: 0.7; }

/* ============================================================
   SPONSORS
============================================================ */
#sponsors { background: #fff; }
.sponsors-tier { margin-bottom: 3rem; }
.sponsors-tier-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(0,0,0,0.35);
  border-bottom: 1px solid #eee;
  padding-bottom: 0.75rem;
  margin-bottom: 1.5rem;
}
.sponsors-logos { display: flex; flex-wrap: wrap; gap: 2rem; align-items: center; }
.sponsor-logo-wrap {
  padding: 1rem 1.5rem;
  border: 1px solid #eee;
  border-radius: 4px;
  display: flex; align-items: center; justify-content: center;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.sponsor-logo-wrap:hover { border-color: var(--pale-violet); box-shadow: 0 4px 16px rgba(68,0,153,0.08); }
.sponsor-logo-wrap img { height: 40px; width: auto; object-fit: contain; }

/* ============================================================
   FOOTER
============================================================ */
#contact {
  background: var(--midnight-black);
  color: #fff;
  padding: 5rem 0 2rem;
}
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 5rem;
  padding-bottom: 4rem;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.contact-brand img { width: auto; display: block; max-width: 160px; object-fit: contain; filter: brightness(0) invert(1); }
.contact-cols { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.contact-col h4 { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; opacity: 0.45; margin-bottom: 1rem; }
.contact-col ul { list-style: none; display: flex; flex-direction: column; gap: 0.5rem; }
.contact-col li a { font-size: 0.875rem; opacity: 0.7; transition: opacity 0.2s; }
.contact-col li a:hover { opacity: 1; }
.contact-foot {
  padding-top: 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  opacity: 0.4;
}

/* ============================================================
   INNER PAGE SECTIONS (conference, for-authors, programme, travel)
============================================================ */
.inner-sections {
  display: flex;
  flex-direction: column;
  gap: 0;
}
.inner-section {
  padding: 4rem 0;
  border-bottom: 1px solid rgba(0,0,0,0.07);
  scroll-margin-top: calc(var(--nav-h) + 60px);
}
.inner-section:last-child { border-bottom: none; }
.inner-section h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--dark-violet);
}
.inner-section p {
  max-width: 680px;
  opacity: 0.8;
  text-wrap: pretty;
  font-size: 1rem;
  line-height: 1.7;
  margin-top: 0.5rem;
}
.inner-section .coming-soon {
  display: inline-block;
  margin-top: 1.5rem;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--brand-violet);
  opacity: 0.6;
}
.inner-section-alt { background: #f8f7ff; }
.inner-section-alt h2 { color: var(--brand-violet); }

/* ============================================================
   KEY DATES TIMELINE  (for-authors.html)
   Edit dates/labels only in the HTML — no CSS changes needed.

   Architecture:
     .timeline               — relative container; hosts the animated line
       .tl-line              — gradient bar, scaleX 0→1 on scroll
       .tl-items             — flex row of equal-width columns, fixed height
         .tl-item            — one milestone; node always at 50% height
           time.tl-date      — in the top half for odd items, bottom for even
           .tl-node          — gradient circle, spring-animates in after line
           p.tl-label        — in the bottom half for odd items, top for even
   At ≤640px the whole thing flips to a vertical left-rail layout.
============================================================ */
.timeline {
  position: relative;
  margin: 2rem 0 1rem;
}
/* Ghost track — always-visible faint line behind the gradient */
.timeline::before {
  content: '';
  position: absolute;
  left: 0; right: 0;
  top: 109px;           /* half of 218px item row */
  height: 2px;
  background: rgba(68, 0, 153, 0.1);
  border-radius: 2px;
  pointer-events: none;
}
/* Animated gradient line */
.tl-line {
  position: absolute;
  left: 0; right: 0;
  top: 109px;
  height: 2px;
  background: linear-gradient(90deg, var(--brand-violet) 0%, var(--electric-violet) 50%, var(--sefi-blue) 100%);
  border-radius: 2px;
  transform-origin: left center;
  transform: scaleX(0);
  transition: transform 1.8s cubic-bezier(0.22, 1, 0.36, 1);
  z-index: 1;
}
.timeline.tl-visible .tl-line { transform: scaleX(1); }

/* Items row */
.tl-items {
  display: flex;
  height: 218px;
  position: relative;
  z-index: 2;
}
.tl-item {
  flex: 1;
  position: relative;
  min-width: 0;
}

/* Node — gradient circle, always at the vertical midpoint */
.tl-node {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-violet), var(--sefi-blue));
  box-shadow: 0 0 0 5px rgba(68, 0, 153, 0.12), 0 2px 12px rgba(0, 119, 255, 0.28);
  transform: translate(-50%, -50%) scale(0);
  opacity: 0;
  transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.3s;
  z-index: 3;
}
/* White centre gives a gradient ring effect */
.tl-node::after {
  content: '';
  position: absolute;
  inset: 6px;
  border-radius: 50%;
  background: #fff;
}
/* Conference node — slightly larger and stronger glow */
.tl-item--last .tl-node {
  width: 30px;
  height: 30px;
  background: linear-gradient(135deg, var(--electric-violet), var(--sefi-blue));
  box-shadow: 0 0 0 6px rgba(112, 0, 255, 0.15), 0 4px 18px rgba(0, 119, 255, 0.38);
}
.tl-item--last .tl-node::after { inset: 8px; }

/* Nodes spring in, staggered to match the line reaching each point */
.timeline.tl-visible .tl-item:nth-child(1) .tl-node { opacity: 1; transform: translate(-50%,-50%) scale(1); }
.timeline.tl-visible .tl-item:nth-child(2) .tl-node { opacity: 1; transform: translate(-50%,-50%) scale(1); transition-delay: 0.25s; }
.timeline.tl-visible .tl-item:nth-child(3) .tl-node { opacity: 1; transform: translate(-50%,-50%) scale(1); transition-delay: 0.50s; }
.timeline.tl-visible .tl-item:nth-child(4) .tl-node { opacity: 1; transform: translate(-50%,-50%) scale(1); transition-delay: 0.75s; }
.timeline.tl-visible .tl-item:nth-child(5) .tl-node { opacity: 1; transform: translate(-50%,-50%) scale(1); transition-delay: 1.00s; }
.timeline.tl-visible .tl-item:nth-child(6) .tl-node { opacity: 1; transform: translate(-50%,-50%) scale(1); transition-delay: 1.25s; }
.timeline.tl-visible .tl-item:nth-child(7) .tl-node { opacity: 1; transform: translate(-50%,-50%) scale(1); transition-delay: 1.50s; }

/* Date — top half of item, text anchored to bottom of zone (just above node) */
.tl-date {
  position: absolute;
  top: 0;
  left: 0; right: 0;
  bottom: calc(50% + 14px);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding: 0 0.3rem 0.55rem;
  font-family: var(--font-serif);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--brand-violet);
  text-align: center;
  line-height: 1.25;
  font-style: normal;
}
/* Label — bottom half, text anchored to top of zone (just below node) */
.tl-label {
  position: absolute;
  top: calc(50% + 14px);
  left: 0; right: 0;
  bottom: 0;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 0.55rem 0.3rem 0;
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--dark-violet);
  text-align: center;
  line-height: 1.3;
  margin: 0;
}

/* Even items: flip — date below, label above */
.tl-item:nth-child(even) .tl-date {
  top: calc(50% + 14px);
  bottom: 0;
  align-items: flex-start;
  padding: 0.55rem 0.3rem 0;
  color: var(--sefi-blue);
}
.tl-item:nth-child(even) .tl-label {
  top: 0;
  bottom: calc(50% + 14px);
  align-items: flex-end;
  padding: 0 0.3rem 0.55rem;
}
/* Conference node text — slightly bolder */
.tl-item--last .tl-date { color: var(--electric-violet); font-weight: 700; }
.tl-item--last .tl-label { font-weight: 700; color: var(--brand-violet); }

/* Small caveat line under h2 */
.tl-caveat {
  font-size: 0.8rem;
  color: var(--midnight-black);
  opacity: 0.55;
  margin: 0.5rem 0 1.75rem;
}

/* ── MOBILE: vertical left-rail layout at ≤640px ── */
@media (max-width: 640px) {
  .timeline { padding-left: 2rem; }
  /* Ghost track becomes vertical */
  .timeline::before {
    top: 0; bottom: 0;
    left: 0; right: auto;
    width: 2px;
    height: auto;
    margin-top: 0;
  }
  /* Animated line becomes vertical */
  .tl-line {
    top: 0; bottom: 0;
    left: 0; right: auto;
    width: 2px;
    height: 100%;
    transform: scaleY(0);
    transform-origin: top center;
    transition: transform 1.8s cubic-bezier(0.22, 1, 0.36, 1);
  }
  .timeline.tl-visible .tl-line { transform: scaleY(1); }
  /* Items stack vertically */
  .tl-items { flex-direction: column; height: auto; gap: 0; }
  .tl-item  { height: auto; padding: 0 0 1.75rem 1.25rem; }
  /* Node sits on the left rail */
  .tl-node {
    top: 0.1rem;
    left: -2rem;
    transform: translate(-50%, 0) scale(0);
    box-shadow: 0 0 0 4px rgba(68, 0, 153, 0.12), 0 2px 8px rgba(0,119,255,0.22);
  }
  .timeline.tl-visible .tl-item:nth-child(1) .tl-node { opacity: 1; transform: translate(-50%,0) scale(1); }
  .timeline.tl-visible .tl-item:nth-child(2) .tl-node { opacity: 1; transform: translate(-50%,0) scale(1); transition-delay: 0.25s; }
  .timeline.tl-visible .tl-item:nth-child(3) .tl-node { opacity: 1; transform: translate(-50%,0) scale(1); transition-delay: 0.50s; }
  .timeline.tl-visible .tl-item:nth-child(4) .tl-node { opacity: 1; transform: translate(-50%,0) scale(1); transition-delay: 0.75s; }
  .timeline.tl-visible .tl-item:nth-child(5) .tl-node { opacity: 1; transform: translate(-50%,0) scale(1); transition-delay: 1.00s; }
  .timeline.tl-visible .tl-item:nth-child(6) .tl-node { opacity: 1; transform: translate(-50%,0) scale(1); transition-delay: 1.25s; }
  .timeline.tl-visible .tl-item:nth-child(7) .tl-node { opacity: 1; transform: translate(-50%,0) scale(1); transition-delay: 1.50s; }
  /* Reset all absolute positioning — become normal flow */
  .tl-date, .tl-label,
  .tl-item:nth-child(even) .tl-date,
  .tl-item:nth-child(even) .tl-label {
    position: static;
    display: block;
    top: auto; bottom: auto; left: auto; right: auto;
    padding: 0;
    text-align: left;
    align-items: unset;
  }
  .tl-date,
  .tl-item:nth-child(even) .tl-date { color: var(--brand-violet); font-size: 0.7rem; margin-bottom: 0.15rem; }
  .tl-label,
  .tl-item:nth-child(even) .tl-label { font-size: 0.9rem; color: var(--dark-violet); }
  .tl-item--last .tl-date { color: var(--electric-violet); }
  .tl-item--last .tl-node { width: 26px; height: 26px; }
  .tl-item--last .tl-node::after { inset: 7px; }
}

/* ============================================================
   BURGER MENU (mobile nav toggle)
============================================================ */
.nav-burger {
  display: none; /* shown only on mobile via media query */
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  flex-shrink: 0;
}
.burger-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: rgba(255,255,255,0.85);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
  transform-origin: center;
}
.nav-burger.open .burger-bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-burger.open .burger-bar:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-burger.open .burger-bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   RESPONSIVE
============================================================ */
@media (max-width: 900px) {
  #about .about-grid,
  .cfp-inner,
  .venue-grid,
  .contact-grid { grid-template-columns: 1fr; gap: 2rem; }
  .about-photo { display: none; }
  .speakers-grid,
  .themes-grid { grid-template-columns: 1fr 1fr; }
  .programme-days { grid-template-columns: 1fr 1fr; }
  .contact-cols { grid-template-columns: 1fr 1fr; }

  /* Nav — tighten outer padding and inner gap so toggle + burger both fit */
  #site-nav   { padding: 0 1rem; }
  .nav-inner  { gap: 1rem; }

  /* Hide desktop elements, show burger */
  .nav-links    { display: none; }
  .nav-wordmark { display: none; }
  #sub-nav      { display: none; }
  .nav-burger   { display: flex; margin-left: auto; }

  /* Mobile nav panel — drops down when burger is open */
  #primary-nav.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: var(--nav-h);
    left: 0; right: 0;
    background: rgba(14, 8, 36, 0.98);
    backdrop-filter: blur(12px);
    padding: 0.5rem 0 1.5rem;
    border-top: 1px solid rgba(255,255,255,0.08);
    z-index: 98;
    box-shadow: 0 8px 32px rgba(0,0,0,0.3);
  }
  #primary-nav.open > li > a {
    padding: 0.9rem 2rem;
    font-size: 1rem;
    color: rgba(255,255,255,0.9);
    border-bottom: 1px solid rgba(255,255,255,0.06);
    display: block;
    width: 100%;
  }
  #primary-nav.open > li > a::after { display: none; }
  #primary-nav.open > li > a.active { color: var(--powder-violet); }
}
@media (max-width: 600px) {
  .speakers-grid,
  .themes-grid,
  .programme-days { grid-template-columns: 1fr; }
}

/* Extra-small phones — compress nav further so burger is never clipped */
@media (max-width: 480px) {
  #site-nav  { padding: 0 0.75rem; }
  .nav-inner { gap: 0.5rem; }
  .simple-toggle { padding: 0.25rem 0.5rem; font-size: 0.72rem; }
  /* Keep toggle-track the same size so the toggle icon is still legible */
}