/* ============================================================
   UTTTA — International Seminar on Urban Transport, Tourism
   and Travel Behavior Analysis
   Fresh academic-conference identity. Editorial + institutional.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Newsreader:ital,opsz,wght@0,6..72,300;0,6..72,400;0,6..72,500;0,6..72,600;1,6..72,300;1,6..72,400&family=IBM+Plex+Sans:wght@300;400;500;600;700&family=IBM+Plex+Mono:wght@400;500;600&display=swap');

:root {
  /* ---- Color ---- */
  --ink:        #0B1B2E;   /* midnight navy — dominant brand */
  --ink-2:      #12283F;
  --ink-soft:   #38516A;
  --ink-mute:   #6E7F8E;
  --paper:      #FBFAF6;   /* warm off-white page ground */
  --surface:    #FFFFFF;
  --sand:       #F1ECE1;   /* warm panel */
  --sand-deep:  #E7E0D1;
  --line:       #E4DDCE;   /* hairline on paper */
  --line-soft:  #EFEADF;

  --accent:      #DC4A2E;  /* persimmon — signature */
  --accent-deep: #B83A21;
  --accent-soft: #FBEAE4;

  --cobalt: #2C5BD6;
  --teal:   #0E8E80;
  --gold:   #D79A2B;

  --on-ink:     #F4F1EA;
  --on-ink-mut: #9DB0C2;

  /* ---- Type ---- */
  --serif: 'Newsreader', Georgia, 'Times New Roman', serif;
  --sans:  'IBM Plex Sans', system-ui, -apple-system, sans-serif;
  --mono:  'IBM Plex Mono', ui-monospace, monospace;

  /* ---- Radius ---- */
  --r-sm: 4px;
  --r-md: 8px;
  --r-lg: 14px;
  --r-xl: 22px;

  /* ---- Shadow ---- */
  --sh-1: 0 1px 2px rgba(11,27,46,.06), 0 1px 1px rgba(11,27,46,.04);
  --sh-2: 0 6px 22px rgba(11,27,46,.08);
  --sh-3: 0 18px 50px rgba(11,27,46,.14);

  /* ---- Layout ---- */
  --wrap: 1200px;
  --wrap-narrow: 880px;
  --header-h: 76px;
  --ease: cubic-bezier(.2,0,0,1);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; color: inherit; }
:focus-visible { outline: none; box-shadow: 0 0 0 3px rgba(44,91,214,.35); border-radius: var(--r-sm); }

/* ---------- typography ---------- */
h1, h2, h3, h4 { font-family: var(--serif); font-weight: 400; line-height: 1.08; letter-spacing: -.01em; color: var(--ink); }
.display { font-size: clamp(2.6rem, 6vw, 4.6rem); font-weight: 500; line-height: 1.02; letter-spacing: -.025em; }
h1 { font-size: clamp(2.1rem, 4.4vw, 3.3rem); }
h2 { font-size: clamp(1.7rem, 3.2vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 2vw, 1.55rem); }
p  { text-wrap: pretty; }
.lede { font-size: clamp(1.12rem, 1.6vw, 1.32rem); line-height: 1.55; color: var(--ink-soft); font-weight: 300; }

.eyebrow {
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .22em;
  text-transform: uppercase;
  font-weight: 500;
  color: var(--accent);
}
.eyebrow.muted { color: var(--ink-mute); }
.serif-italic { font-style: italic; font-family: var(--serif); }

/* ---------- layout ---------- */
.wrap { width: 100%; max-width: var(--wrap); margin-inline: auto; padding-inline: 28px; }
.wrap.narrow { max-width: var(--wrap-narrow); }
.section { padding-block: clamp(56px, 8vw, 110px); }
.section.tight { padding-block: clamp(40px, 5vw, 64px); }
.section-head { max-width: 720px; margin-bottom: 48px; }
.section-head .eyebrow { display: block; margin-bottom: 16px; }
.section-head h2 { margin-bottom: 16px; }

.grid { display: grid; gap: 28px; }
.cols-2 { grid-template-columns: repeat(2, 1fr); }
.cols-3 { grid-template-columns: repeat(3, 1fr); }
.cols-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 920px){ .cols-3, .cols-4 { grid-template-columns: repeat(2,1fr); } }
@media (max-width: 720px){ .cols-2, .cols-3, .cols-4 { grid-template-columns: 1fr; } }

.bg-ink   { background: var(--ink); color: var(--on-ink); }
.bg-ink h1, .bg-ink h2, .bg-ink h3 { color: var(--on-ink); }
.bg-sand  { background: var(--sand); }
.bg-surface { background: var(--surface); }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 14px 26px; border-radius: 999px;
  font-family: var(--sans); font-weight: 600; font-size: .96rem;
  border: 1.5px solid transparent; cursor: pointer;
  transition: transform .12s var(--ease), background .18s var(--ease), color .18s var(--ease), border-color .18s var(--ease);
}
.btn svg { width: 18px; height: 18px; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-deep); }
.btn-primary:active { transform: scale(.98); }
.btn-ink { background: var(--ink); color: var(--on-ink); }
.btn-ink:hover { background: var(--ink-2); }
.btn-ghost { background: transparent; border-color: var(--line); color: var(--ink); }
.btn-ghost:hover { border-color: var(--ink); }
.btn-on-ink { background: var(--on-ink); color: var(--ink); }
.btn-on-ink:hover { background: #fff; }
.btn-outline-ink { background: transparent; border-color: rgba(244,241,234,.35); color: var(--on-ink); }
.btn-outline-ink:hover { border-color: var(--on-ink); }
.btn-lg { padding: 17px 34px; font-size: 1.02rem; }
.btn-sm { padding: 10px 18px; font-size: .85rem; }

.link-arrow { display: inline-flex; align-items: center; gap: 8px; font-weight: 600; color: var(--accent); border-bottom: 1.5px solid transparent; padding-bottom: 1px; transition: gap .15s var(--ease), border-color .15s; }
.link-arrow svg { width: 17px; height: 17px; transition: transform .15s var(--ease); }
.link-arrow:hover { border-color: var(--accent); }
.link-arrow:hover svg { transform: translateX(3px); }

/* ---------- chips / tags ---------- */
.chip {
  display: inline-flex; align-items: center; gap: 7px;
  font-family: var(--mono); font-size: .72rem; letter-spacing: .04em;
  padding: 6px 12px; border-radius: 999px;
  background: var(--sand); color: var(--ink-soft); font-weight: 500;
  border: 1px solid var(--line);
}
.chip.solid { background: var(--ink); color: var(--on-ink); border-color: var(--ink); }
.chip.accent { background: var(--accent-soft); color: var(--accent-deep); border-color: transparent; }
.chip .dot { width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
.country-flag { font-size: .85rem; }

/* ---------- cards ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: 28px;
  transition: box-shadow .2s var(--ease), transform .2s var(--ease), border-color .2s;
}
.card.hover:hover { box-shadow: var(--sh-2); transform: translateY(-2px); border-color: var(--sand-deep); }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(251,250,246,.86);
  backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header.scrolled { box-shadow: var(--sh-1); }
.nav {
  height: var(--header-h);
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.brand { display: flex; align-items: center; gap: 13px; }
.brand .mark { width: 42px; height: 42px; flex: none; }
.brand .brand-txt { display: flex; flex-direction: column; line-height: 1.05; }
.brand .brand-txt b { font-family: var(--mono); font-weight: 600; font-size: .96rem; letter-spacing: .12em; color: var(--ink); }
.brand .brand-txt span { font-size: .68rem; color: var(--ink-mute); letter-spacing: .04em; margin-top: 2px; }
.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-links a {
  font-size: .92rem; font-weight: 500; color: var(--ink-soft);
  padding: 9px 13px; border-radius: var(--r-md);
  transition: color .15s, background .15s;
}
.nav-links a:hover { color: var(--ink); background: var(--sand); }
.nav-links a.active { color: var(--accent); }
.nav-actions { display: flex; align-items: center; gap: 12px; }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }
.nav-toggle svg { width: 26px; height: 26px; }

@media (max-width: 1080px){
  .nav-links { display: none; }
  .nav-toggle { display: block; }
  .nav-links.open {
    display: flex; flex-direction: column; align-items: stretch; gap: 2px;
    position: absolute; top: var(--header-h); left: 0; right: 0;
    background: var(--surface); border-bottom: 1px solid var(--line);
    padding: 14px 20px 22px; box-shadow: var(--sh-2);
  }
  .nav-links.open a { padding: 13px 14px; font-size: 1rem; }
  .nav .btn.hide-mobile { display: none; }
}

/* ---------- footer ---------- */
.site-footer { background: var(--ink); color: var(--on-ink-mut); padding-block: 64px 40px; }
.site-footer h4 { color: var(--on-ink); font-family: var(--sans); font-size: .8rem; letter-spacing: .14em; text-transform: uppercase; font-weight: 600; margin-bottom: 18px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.2fr; gap: 40px; margin-bottom: 48px; }
@media (max-width: 860px){ .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; } }
@media (max-width: 520px){ .footer-grid { grid-template-columns: 1fr; } }
.site-footer a { color: var(--on-ink-mut); transition: color .15s; display: block; padding: 5px 0; font-size: .92rem; }
.site-footer a:hover { color: var(--on-ink); }
.footer-brand p { color: var(--on-ink-mut); font-size: .92rem; max-width: 30ch; margin-top: 16px; }
.footer-bottom { border-top: 1px solid rgba(244,241,234,.12); padding-top: 26px; display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font-size: .82rem; }
.footer-bottom .mono { font-family: var(--mono); letter-spacing: .04em; }

/* ---------- hero route motif ---------- */
.route-svg .node-pulse { animation: pulse 2.6s var(--ease) infinite; transform-box: fill-box; transform-origin: center; }
@keyframes pulse { 0%,100%{ opacity: .9; } 50%{ opacity: .35; } }
@media (prefers-reduced-motion: reduce){ .route-svg .node-pulse { animation: none; } }

/* ---------- forms ---------- */
.field { display: flex; flex-direction: column; gap: 7px; margin-bottom: 20px; }
.field label { font-size: .85rem; font-weight: 600; color: var(--ink-soft); }
.field label .req { color: var(--accent); }
.field .hint { font-size: .78rem; color: var(--ink-mute); }
.input, .select, .textarea {
  width: 100%; padding: 13px 15px; background: var(--surface);
  border: 1.5px solid var(--line); border-radius: var(--r-md);
  font-size: .96rem; transition: border-color .15s, box-shadow .15s;
}
.input:focus, .select:focus, .textarea:focus { border-color: var(--cobalt); box-shadow: 0 0 0 3px rgba(44,91,214,.14); outline: none; }
.input.err, .select.err { border-color: var(--accent); }
.textarea { resize: vertical; min-height: 110px; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
@media (max-width: 620px){ .field-row { grid-template-columns: 1fr; } }
.err-msg { font-size: .78rem; color: var(--accent-deep); font-weight: 500; }
.checkbox-row { display: flex; gap: 11px; align-items: flex-start; }
.checkbox-row input { margin-top: 4px; width: 18px; height: 18px; accent-color: var(--accent); flex: none; }

/* ---------- program table ---------- */
.prog-day { margin-bottom: 14px; }
.prog-row {
  display: grid; grid-template-columns: 150px 1fr; gap: 28px;
  padding: 22px 0; border-top: 1px solid var(--line);
}
.prog-row:last-child { border-bottom: 1px solid var(--line); }
.prog-time { font-family: var(--mono); font-size: .9rem; color: var(--ink-soft); font-weight: 500; padding-top: 2px; }
.prog-body h4 { font-family: var(--sans); font-weight: 600; font-size: 1.08rem; margin-bottom: 5px; }
.prog-body .meta { font-size: .9rem; color: var(--ink-mute); }
@media (max-width: 620px){ .prog-row { grid-template-columns: 1fr; gap: 8px; } }

/* ---------- misc ---------- */
.divider-lines { height: 3px; background: linear-gradient(90deg, var(--accent) 0 25%, var(--cobalt) 25% 50%, var(--teal) 50% 75%, var(--gold) 75% 100%); border-radius: 3px; }
.kicker-num { font-family: var(--serif); font-size: clamp(3rem,7vw,5rem); font-weight: 300; color: var(--accent); line-height: 1; }
.muted { color: var(--ink-mute); }
.center { text-align: center; }
.mt-s{margin-top:12px}.mt-m{margin-top:24px}.mt-l{margin-top:40px}
.mb-s{margin-bottom:12px}.mb-m{margin-bottom:24px}
.flex { display: flex; } .gap-s{gap:10px}.gap-m{gap:18px} .wrap-flex{flex-wrap:wrap} .items-center{align-items:center}
.stat-num { font-family: var(--serif); font-size: clamp(2.4rem,5vw,3.4rem); font-weight: 400; color: var(--ink); line-height: 1; }
.stat-label { font-size: .85rem; color: var(--ink-mute); margin-top: 8px; }
.img-ph {
  background: linear-gradient(135deg, var(--sand) 0%, var(--sand-deep) 100%);
  position: relative; display: flex; align-items: center; justify-content: center;
  color: var(--ink-mute); overflow: hidden; border-radius: var(--r-lg);
}
.img-ph .ph-label { font-family: var(--mono); font-size: .72rem; letter-spacing: .1em; text-transform: uppercase; z-index: 2; text-align: center; padding: 12px; }
.img-ph::after { content:''; position:absolute; inset:0; background-image: radial-gradient(circle at 1px 1px, rgba(11,27,46,.07) 1px, transparent 0); background-size: 14px 14px; }
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s var(--ease), transform .6s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce){ .reveal { opacity: 1; transform: none; } }

/* ---------- inner page hero ---------- */
.page-hero { background: var(--ink); color: var(--on-ink); position: relative; overflow: hidden; padding-block: clamp(54px, 8vw, 96px) clamp(40px, 6vw, 72px); }
.page-hero::before { content:''; position:absolute; inset:0; background: radial-gradient(800px 420px at 88% 10%, rgba(44,91,214,.22), transparent 60%), radial-gradient(560px 360px at 100% 100%, rgba(220,74,46,.14), transparent 55%); }
.page-hero::after { content:''; position:absolute; inset:0; background-image: radial-gradient(circle at 1px 1px, rgba(244,241,234,.06) 1px, transparent 0); background-size: 26px 26px; mask-image: linear-gradient(90deg, transparent, #000 40%); }
.page-hero .inner { position: relative; }
.crumb { font-family: var(--mono); font-size: .72rem; letter-spacing: .14em; text-transform: uppercase; color: var(--on-ink-mut); display:flex; gap:9px; align-items:center; margin-bottom: 22px; }
.crumb a { color: var(--on-ink-mut); } .crumb a:hover { color:#fff; } .crumb .sep { opacity:.5; }
.page-hero h1 { color:#fff; max-width: 18ch; }
.page-hero .ph-lede { color: var(--on-ink-mut); font-size: clamp(1.05rem,1.6vw,1.28rem); font-weight:300; max-width: 56ch; margin-top: 20px; }
.page-hero .ph-divider { width: 130px; margin-top: 28px; }

/* prose */
.prose { max-width: 70ch; }
.prose p { margin-bottom: 20px; color: var(--ink-soft); font-size: 1.06rem; }
.prose p:first-of-type { font-size: 1.16rem; color: var(--ink); }
.prose h3 { margin: 38px 0 14px; }
.prose ul { margin: 0 0 20px; padding-left: 0; list-style: none; }
.prose ul li { position: relative; padding-left: 26px; margin-bottom: 12px; color: var(--ink-soft); }
.prose ul li::before { content:''; position:absolute; left:4px; top:11px; width:7px; height:7px; border-radius:50%; background: var(--accent); }

/* info card list */
.info-card { display:flex; gap:18px; align-items:flex-start; padding:24px; background:var(--surface); border:1px solid var(--line); border-radius: var(--r-lg); }
.info-card .ic { width:46px; height:46px; flex:none; border-radius:var(--r-md); background: var(--accent-soft); color: var(--accent-deep); display:flex; align-items:center; justify-content:center; }
.info-card .ic svg { width:22px; height:22px; }
.info-card h4 { font-family: var(--sans); font-weight:600; font-size:1.04rem; margin-bottom:5px; }
.info-card p { font-size:.94rem; color: var(--ink-soft); }

/* people grid */
.people-grid { display:grid; grid-template-columns: repeat(3,1fr); gap:20px; }
@media (max-width: 860px){ .people-grid { grid-template-columns: repeat(2,1fr); } }
@media (max-width: 560px){ .people-grid { grid-template-columns: 1fr; } }
.person { background:var(--surface); border:1px solid var(--line); border-radius: var(--r-lg); padding:24px; transition: box-shadow .2s var(--ease), transform .2s var(--ease); }
.person:hover { box-shadow: var(--sh-2); transform: translateY(-2px); }
.person .avatar { width:56px; height:56px; border-radius:50%; background: var(--ink); color:#fff; display:flex; align-items:center; justify-content:center; font-family: var(--serif); font-size:1.35rem; margin-bottom:16px; position:relative; overflow:hidden; }
.person .avatar img { position:absolute; inset:0; width:100%; height:100%; object-fit:cover; object-position:center top; }
.person .role { display:inline-block; font-family: var(--mono); font-size:.66rem; letter-spacing:.1em; text-transform:uppercase; color: var(--accent-deep); background: var(--accent-soft); padding:4px 9px; border-radius:999px; margin-bottom:12px; }
.person h3 { font-family: var(--sans); font-weight:600; font-size:1.12rem; margin-bottom:4px; }
.person .ptitle { font-size:.9rem; color: var(--ink-soft); }
.person .porg { font-size:.86rem; color: var(--ink-mute); margin-top:6px; display:flex; gap:7px; align-items:center; }

/* timeline (cfp / archive) */
.timeline { position:relative; padding-left: 30px; }
.timeline::before { content:''; position:absolute; left:7px; top:6px; bottom:6px; width:2px; background: var(--line); }
.tl-item { position:relative; padding-bottom: 30px; }
.tl-item:last-child { padding-bottom:0; }
.tl-item .dot { position:absolute; left:-30px; top:3px; width:16px; height:16px; border-radius:50%; background:var(--surface); border:2px solid var(--line); }
.tl-item.done .dot { background: var(--ink); border-color: var(--ink); }
.tl-item.open .dot { background: var(--accent); border-color: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); }
.tl-item .tl-date { font-family: var(--mono); font-size:.8rem; letter-spacing:.04em; color: var(--ink-mute); }
.tl-item .tl-label { font-weight:600; font-size:1.05rem; margin-top:3px; }
.tl-item.open .tl-label { color: var(--accent-deep); }

/* archive rows */
.arch-row { display:grid; grid-template-columns: 90px 1fr auto; gap:24px; align-items:center; padding:26px 0; border-top:1px solid var(--line); }
.arch-row:last-child { border-bottom:1px solid var(--line); }
.arch-row .ed { font-family: var(--serif); font-size:2rem; font-weight:300; color: var(--ink); line-height:1; }
.arch-row.current .ed { color: var(--accent); }
.arch-row h3 { font-family: var(--sans); font-weight:600; font-size:1.18rem; margin-bottom:4px; }
.arch-row .host { font-size:.92rem; color: var(--ink-mute); }
@media (max-width:620px){ .arch-row { grid-template-columns: 70px 1fr; } .arch-row .yr { grid-column: 2; } }