/* ======================================================
   DESIGN SYSTEM (variables, shared tokens)
   - change colors / sizes here
====================================================== */
:root{
  --accent: #2f4a6d;
  --accent-light: #e9eef4;
  --border: #e5e5e5;
  --text-muted: #666;

  /* layout widths */
  --page-max-width: 1050px;   /* middle column width */
  --content-max-width: 1000px; /* main content width */
  --hero-inner-width: 1000px; /* hero text width */

  /* spacing */
  --gutter: 24px;
  --base-pad: 20px;
  --header-height: 60px;
  --radius-sm: 4px;
  --transition-fast: 0.18s;
}

/* ======================================================
   BASE / RESET
====================================================== */
* { box-sizing: border-box; }
html,body { height: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
               Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: #222;
  background-color: #f4f4f4; /* outside area */
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

/* central page container (middle column) */
.page-container {
  max-width: var(--page-max-width);
  margin: 0 auto;
  background: #fff;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  width: 100%;
  box-sizing: border-box;
  overflow-x: hidden;
  overflow-y: visible;
}

/* basic link styles */
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* small utility */
.sr-only {
  position:absolute !important;
  height:1px;width:1px;overflow:hidden;clip:rect(1px,1px,1px,1px);
  white-space:nowrap;border:0;padding:0;margin:-1px;
}

/* ======================================================
   HEADER (logo + title)
====================================================== */
/* ===========================
   HEADER + NAVBAR MERGED
=========================== */

/* ---------- NAVBAR ---------- */
.header-bar {
  position: sticky;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  background: #f8f8f8;
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  overflow: visible;
  width: 100%;
  box-sizing: border-box;
  flex-shrink: 0;
}


/* logo + title */
.header-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.header-left .logo {
  height: 50px;
}

.header-left .title-text .line1 {
  font-weight: 700;
  color: var(--accent);
  font-size: 1.3rem;
}

.header-left .title-text .line2 {
  font-size: 0.85rem;
  color: #555;
}

/* nav links (desktop) */
.nav-links {
  display: flex;
  gap: 20px;
  list-style: none;
}

.nav-links a {
  padding: 6px 10px;
  border-radius: 4px;
  text-decoration: none;
  color: #222;
  font-weight: 500;
  transition: all 0.2s;
}

.nav-links a:hover {
  background: var(--accent-light);
  color: var(--accent);
}

.nav-links a.active {
  background: var(--accent);
  color: #fff;
}

/* ---------- HAMBURGER ---------- */
.nav-toggle {
  display: none; /* shown only on mobile */
  background: none;
  border: none;
  font-size: 2rem; /* adjust size */
  cursor: pointer;
  z-index: 1500;
  position: relative;
}

.nav-toggle .icon-close {
  display: none; /* hidden by default */
}

/* When active: show close icon, hide hamburger */
.nav-toggle.active .icon-hamburger {
  display: none;
}

.nav-toggle.active .icon-close {
  display: inline;
}



/* ---------- MOBILE ---------- */
@media (max-width: 1000px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;           /* just below header */
    right: 0;            /* align to the right edge */
    flex-direction: column;
    background: #fff;
    padding: 12px 20px;
    gap: 12px;
    border-radius: 6px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    width: 220px;        /* fixed width for consistency */
    text-align: center;  /* center-align text */
    z-index: 1500;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    display: block;
    font-size: 1.1rem;
    padding: 10px 0;
    color: #222;
    transition: color 0.2s, background 0.2s;
  }

  .nav-links a:hover {
    color: var(--accent);
    background: var(--accent-light);
    border-radius: 4px;
  }

  .nav-toggle {
    display: flex;
    position: relative;
    z-index: 1600;
  }
}




/* ======================================================
   HERO
   (background area spans middle column; inner text constrained)
====================================================== */
.hero {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 72px var(--gutter);
  background-color: var(--accent);
  background-image: linear-gradient(rgba(0,0,0,0.3), rgba(0,0,0,0.15)),
                    url('images/viewbannerimage_2.jpg');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.hero-inner {
  max-width: var(--hero-inner-width);
  width: 100%;
  padding: 0 var(--base-pad);
  text-align: center;
  color: #fff;
  text-shadow: 0 1px 6px rgba(0,0,0,0.55);
}

.hero-text h1 {
  font-size: 2.6rem;
  margin: 0;
  line-height: 1.05;
}

.hero-text p {
  margin-top: 0.6rem;
  font-size: 1.1rem;
  opacity: 0.95;
}

.hero-text .btn {
  display: inline-block;
  margin-top: 20px;
  background: #fff;
  color: var(--accent);
  padding: 12px 28px;
  border-radius: 30px;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.2s;
}

.hero-text .btn:hover {
  background: #e6e6e6;
  transform: translateY(-2px);
}

@media (max-width: 768px) {
  .hero {
    padding: 48px 20px;
  }
  .hero-text h1 {
    font-size: 2rem;
  }
  .hero-text p {
    font-size: 1rem;
  }
  .nav-links {
    gap: 16px;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 32px 12px;
  }
  .hero-text h1 {
    font-size: 1.6rem;
  }
  .hero-text p {
    font-size: 0.95rem;
  }
  .nav-links {
    flex-direction: column;
    gap: 12px;
  }
}
/* ======================================================
   HERO CAROUSEL (matches hero style)
====================================================== */
.hero-carousel {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 72px var(--gutter);
  height: 25vw;               /* scales with viewport width */
  min-height: 180px;          /* prevents it from being too small */
  max-height: 300px;          /* prevents it from being too tall */
  overflow: hidden;
  background-color: var(--accent);
}


.hero-slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-size: cover;
  background-position: center;
  opacity: 0;
  transition: opacity 1s ease-in-out;
}

.hero-slide.active {
  opacity: 1;
}

/* Dots */
.hero-dots {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 10;
}

.hero-dots .dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background-color: rgba(255,255,255,0.5);
  cursor: pointer;
  transition: background-color 0.3s ease;
}

.hero-dots .dot.active {
  background-color: #fff;
}

/* Arrows */
.hero-prev,
.hero-next {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  font-size: 2rem;
  background: rgba(0,0,0,0.3);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 44px;
  height: 44px;
  cursor: pointer;
  z-index: 10;
  display: none;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}

.hero-prev:hover,
.hero-next:hover {
  background: rgba(0,0,0,0.6);
}

.hero-prev { left: 20px; }
.hero-next { right: 20px; }

/* ================= HERO INNER (if you want to place overlay text later) ================= */
.hero-carousel-inner {
  max-width: var(--hero-inner-width); /* matches hero inner width */
  width: 100%;
  text-align: center;
  z-index: 5;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .hero-carousel { padding: 48px var(--gutter); }
  .hero-prev, .hero-next { width: 36px; height: 36px; font-size: 1.5rem; }
  .hero-dots .dot { width: 10px; height: 10px; }
}

@media (max-width: 480px) {
  .hero-carousel { padding: 32px var(--gutter); }
  .hero-prev, .hero-next { width: 32px; height: 32px; font-size: 1.2rem; }
  .hero-dots .dot { width: 8px; height: 8px; }
}

/* ======================================================
   MAIN CONTENT
====================================================== */
main {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 48px var(--gutter);
  width: 100%;
}

section { margin-bottom: 56px; }

h1 { font-size: 2.2rem; margin-bottom: .4rem; }
h2 { font-size: 1.25rem; color: var(--accent); margin-bottom: .8rem; }

/* meta box (information cards) */
.meta-box {
  background: #f9f9f9;
  border-left: 4px solid var(--accent);
  padding: 18px 22px;
  margin: 18px 0;
  border-radius: 4px;
}

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

/* ======================================================
   SCHEDULE (grid layout)
====================================================== */
.schedule {
  margin-top: 24px;
  display: grid;
  grid-template-columns: 120px 1fr;
  column-gap: 20px;
  row-gap: 18px;
}

.talk {
  display: contents; /* allow grid to place children */
}

.time, .talk .time {
  font-weight: 600;
  color: var(--accent);
  align-self: start;
  font-size: .95rem;
}

.content, .talk .content {
  display: block;
}

.title, .talk .title {
  font-weight: 600;
  margin-bottom: 6px;
  cursor: pointer;
}

.abstract, .talk .abstract {
  font-size: .95rem;
  color: var(--text-muted);
  display: none;
  line-height: 1.4;
  margin-bottom: 8px;
}

.talk.open .abstract { display: block; }

/* day toggle (buttons) */
.day-toggle { display:flex; gap:12px; margin-bottom: 18px; }
.day-toggle button {
  padding: 6px 14px;
  border: 1px solid var(--accent);
  background:#fff;
  color:var(--accent);
  border-radius: 6px;
  cursor:pointer;
}
.day-toggle button.active,
.day-toggle button:hover { background:var(--accent); color:#fff; }

/* small visual divider for sections */
.section-divider { height:1px; background:var(--border); margin:28px 0; }

/* ======================================================
   FOOTER
====================================================== */
footer {
  text-align: center;
  padding: 28px var(--gutter);
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: .95rem;
  margin-top: auto;
  background: #fff;
}

/* ======================================================
   RESPONSIVE RULES (mobile-first adjustments)
====================================================== */
/* breakpoints */
@media (max-width: 1200px){
  :root { /* slightly reduce hero/text widths on narrower screens if desired */
    --hero-inner-width: 900px;
  }
  .nav-inner { padding: 0 18px; }
}

@media (max-width: 900px){
  .page-container { padding: 0 12px; }
  main { padding: 32px 16px; }
  .hero { padding: 56px 16px; }
  .hero-text h1 { font-size: 2rem; }
  .title-text .line1 { font-size: 1.25rem; }
}

@media (max-width: 640px){
  .nav-links { flex-direction: column; gap: 8px; padding: 10px 0; }
  .header-top { flex-direction: column; align-items: flex-start; gap: 10px; padding: 12px; }
  .hero { padding: 36px 12px; }
  main { padding: 20px 12px; }
  .schedule { grid-template-columns: 100px 1fr; }
  .title-text .line1 { font-size: 1.05rem; }
  .hero-text h1 { font-size: 1.6rem; }
}

/* small helpers */
.center { text-align:center; }
.btn {
  display:inline-block;
  background:var(--accent);
  color:#fff;
  padding:10px 16px;
  border-radius:6px;
  font-weight:600;
  text-decoration:none;
  transition: background var(--transition-fast);
}
.btn:hover { background:#24435a; }


    /* ===== Speakers Section ===== */

.speakers-section {
  max-width: 1000px;
  margin: 5px auto;
  padding: 0 20px;
}

.speaker-category-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 30px;
  padding: 0 2px;
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
}

.speaker-category-tab {
  min-width: 220px;
  padding: 12px 18px;
  border: 1px solid transparent;
  border-bottom: 3px solid transparent;
  background: #fff;
  cursor: pointer;
  text-align: center;
  border-radius: 4px 4px 0 0;
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: 0.01em;
  color: var(--text-muted);
  transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast), border-bottom-color var(--transition-fast);
}

.speaker-category-tab:hover {
  color: var(--accent);
  background: #fff;
  border-color: var(--border);
  border-bottom-color: var(--accent-light);
}

.speaker-category-tab.active {
  border-color: var(--border);
  border-bottom: 4px solid var(--accent);
  color: var(--accent);
  font-weight: 700;
  background: #f5f5f5;
}

.speaker-note {
  margin: 4px 2px 18px;
  padding: 6px 10px;
  display: inline-block;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 0.92rem;
  color: var(--text-muted);
  background: #f8f8f8;
  border-left: 3px solid var(--border);
}

.speaker-tabs {
  display: flex;
  gap: 10px;
  border-bottom: 1px solid #eee;
  margin-bottom: 40px;
  overflow-x: auto;
}

.speaker-tab {
  padding: 14px 22px;
  border: none;
  background: none;
  cursor: pointer;
  border-bottom: 4px solid transparent;
  font-weight: 500;
  color: #666;
  transition: 0.2s ease;
}

.speaker-tab.active {
  border-bottom: 4px solid #003366;
  color: #003366;
  font-weight: 700;
  background: #f8fafc;
}

.speaker-content {
  display: flex;
  flex-wrap: wrap;
  gap: 40px;
}

.speaker-photo {
  flex: 0 0 180px;
}

.speaker-photo img {
  width: 100%;
  aspect-ratio: 3/4;
  object-fit: cover;
  border-radius: 12px;
  background: #f5f5f5;
}

.speaker-details {
  flex: 1 1 450px;
}

.speaker-type {
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: #003366;
  margin-bottom: 10px;
}

.speaker-name {
  margin: 0 0 15px 0;
  font-size: 1.8rem;
}

.speaker-title {
  font-weight: 600;
  color: #003366;
  margin-bottom: 6px;
}

.speaker-affiliation {
  margin-bottom: 12px;
  color: #555;
  line-height: 1.5;
}

.speaker-email {
  color: #003366;
  text-decoration: none;
}

.speaker-abstract-box {
  display: none;
  margin-top: 25px;
  background: #f9f9f9;
  padding: 20px;
  border-left: 3px solid #003366;
  border-radius: 10px;
}