/* ============================================================
   3DPNV 2026 — Hi! PARIS Workshop on 3D Perception and Navigation
   Light & modern theme
   ============================================================ */

:root {
  --bg: #ffffff;
  --bg-alt: #f5f8fc;
  --bg-hero: #eef4fd;
  --ink: #0f1b2d;
  --ink-soft: #475569;
  --ink-faint: #7c8aa0;
  --line: #e3eaf3;
  --brand: #1d4ed8;
  --brand-dark: #1736a8;
  --brand-soft: #e7efff;
  --accent: #0ea5e9;
  --accent-2: #06b6d4;
  --ok: #0f9d58;
  --ok-bg: #e6f6ee;
  --warn: #b7791f;
  --warn-bg: #fdf3e2;
  --tba: #6b7280;
  --tba-bg: #eef1f5;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px -12px rgba(16, 42, 92, 0.18);
  --shadow-sm: 0 4px 14px -8px rgba(16, 42, 92, 0.25);
  --maxw: 1120px;
  --font: "Inter", system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  --display: "Space Grotesk", var(--font);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
.narrow { max-width: 820px; }
.center { text-align: center; }

img, svg, iframe { max-width: 100%; }

/* ---------------- Navbar ---------------- */
.navbar {
  position: sticky; top: 0; z-index: 60;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 66px; }

.brand { display: flex; align-items: center; gap: 10px; font-family: var(--display); font-weight: 700; font-size: 1.18rem; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand-mark svg circle { fill: var(--brand); }
.brand-mark { display: inline-flex; }
.brand-year { color: var(--brand); }

.nav-links { display: flex; align-items: center; gap: 26px; }
.nav-links a { color: var(--ink-soft); font-weight: 500; font-size: 0.96rem; }
.nav-links a:hover { color: var(--brand); text-decoration: none; }
.nav-cta {
  background: var(--brand); color: #fff !important; padding: 8px 16px;
  border-radius: 999px; font-weight: 600 !important;
}
.nav-cta:hover { background: var(--brand-dark); }

.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--ink); border-radius: 2px; transition: 0.25s; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------------- Hero ---------------- */
.hero {
  position: relative; overflow: hidden;
  background: linear-gradient(170deg, var(--bg-hero) 0%, #ffffff 70%);
  padding: 92px 0 84px;
  border-bottom: 1px solid var(--line);
}
.hero-bg { position: absolute; inset: 0; pointer-events: none; }
.hero-bg .dots { width: 100%; height: 100%; opacity: 0.5; }
.hero-bg .dots circle { fill: var(--brand); }
.hero-bg .dots line { stroke: var(--accent); stroke-width: 0.6; }

.hero-inner { position: relative; z-index: 2; max-width: 880px; }
.hero-eyebrow {
  display: inline-block; margin: 0 0 14px; font-weight: 600; letter-spacing: 0.06em;
  text-transform: uppercase; font-size: 0.8rem; color: var(--brand);
  background: var(--brand-soft); padding: 6px 14px; border-radius: 999px;
}
.hero-title {
  font-family: var(--display); font-weight: 700; line-height: 1.05;
  font-size: clamp(2.3rem, 6vw, 4rem); margin: 0 0 18px; letter-spacing: -0.02em;
}
.hero-title .grad {
  background: linear-gradient(100deg, var(--brand), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-sub { font-size: clamp(1.05rem, 2.3vw, 1.3rem); color: var(--ink-soft); margin: 0 0 28px; max-width: 620px; }

.hero-meta { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 30px; }
.meta-pill {
  display: inline-flex; align-items: center; gap: 9px;
  background: #fff; border: 1px solid var(--line); border-radius: 999px;
  padding: 9px 16px; font-weight: 600; font-size: 0.95rem; box-shadow: var(--shadow-sm);
}
.meta-pill svg { fill: none; stroke: var(--brand); stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }

/* ---------------- Buttons ---------------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 13px 26px; border-radius: 999px; font-weight: 600; font-size: 0.98rem;
  cursor: pointer; transition: transform 0.15s ease, box-shadow 0.2s ease, background 0.2s ease;
  border: 1px solid transparent;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn-primary { background: var(--brand); color: #fff; box-shadow: var(--shadow); }
.btn-primary:hover { background: var(--brand-dark); }
.btn-ghost { background: #fff; color: var(--brand); border-color: #c9d8f5; }
.btn-ghost:hover { border-color: var(--brand); background: var(--brand-soft); }

/* ---------------- Sections ---------------- */
.section { padding: 80px 0; }
.section-alt { background: var(--bg-alt); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }

.kicker {
  margin: 0 0 10px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase;
  font-size: 0.78rem; color: var(--accent);
}
.kicker.center { text-align: center; }
.section-title {
  font-family: var(--display); font-weight: 700; letter-spacing: -0.02em;
  font-size: clamp(1.7rem, 3.6vw, 2.5rem); margin: 0 0 18px; line-height: 1.12;
}
.section-note { color: var(--ink-faint); margin: -6px 0 26px; font-size: 0.96rem; }
.lead { font-size: 1.12rem; color: var(--ink-soft); margin: 0 0 24px; }
.lead strong { color: var(--ink); }

/* ---------------- About ---------------- */
.chips { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 40px; }
.chip {
  background: var(--brand-soft); color: var(--brand-dark); font-weight: 600; font-size: 0.9rem;
  padding: 7px 15px; border-radius: 999px; border: 1px solid #d4e2ff;
}

.facts { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.fact {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 24px 18px; text-align: center; box-shadow: var(--shadow-sm);
}
.fact-num {
  display: block; font-family: var(--display); font-weight: 700; font-size: 2.4rem;
  color: var(--brand); line-height: 1;
}
.fact-label { display: block; margin-top: 8px; color: var(--ink-soft); font-size: 0.92rem; }

/* ---------------- Schedule ---------------- */
.sched-tabs { display: inline-flex; gap: 6px; background: #fff; border: 1px solid var(--line); border-radius: 999px; padding: 5px; margin-bottom: 34px; box-shadow: var(--shadow-sm); flex-wrap: wrap; }
.tab {
  border: 0; background: none; cursor: pointer; font-family: var(--font);
  font-weight: 600; font-size: 0.95rem; color: var(--ink-soft);
  padding: 10px 20px; border-radius: 999px; transition: 0.2s;
}
.tab.active { background: var(--brand); color: #fff; }

.sched-panel { animation: fade 0.35s ease; }
.sched-panel[hidden] { display: none; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.session-label {
  font-family: var(--display); font-weight: 600; color: var(--ink-faint);
  text-transform: uppercase; letter-spacing: 0.1em; font-size: 0.78rem;
  margin: 22px 0 8px; padding-left: 4px;
}

.timeline { display: flex; flex-direction: column; gap: 12px; }
.t-item {
  display: grid; grid-template-columns: 130px 1fr; gap: 18px; align-items: start;
  background: #fff; border: 1px solid var(--line); border-left: 4px solid var(--line);
  border-radius: var(--radius-sm); padding: 16px 20px; box-shadow: var(--shadow-sm);
  transition: transform 0.15s ease, box-shadow 0.2s ease;
}
.t-item:hover { transform: translateX(3px); box-shadow: var(--shadow); }
.t-time { font-weight: 700; color: var(--ink); font-variant-numeric: tabular-nums; font-size: 1.02rem; }
.t-time span { display: block; color: var(--ink-faint); font-weight: 500; font-size: 0.86rem; }
.t-title { margin: 0; font-size: 1.08rem; font-weight: 600; }
.t-meta { margin: 4px 0 0; color: var(--ink-soft); font-size: 0.94rem; }
.t-tags { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 6px; }

.tag {
  font-size: 0.72rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.04em;
  padding: 3px 9px; border-radius: 6px; background: var(--tba-bg); color: var(--tba);
}
.tag-keynote { background: var(--brand-soft); color: var(--brand-dark); }
.tag-poster { background: #efe7fb; color: #6b21a8; }
.tag-ok { background: var(--ok-bg); color: var(--ok); }
.tag-tbc { background: var(--warn-bg); color: var(--warn); }
.tag-tba { background: var(--tba-bg); color: var(--tba); }

.type-keynote { border-left-color: var(--brand); }
.type-talk { border-left-color: var(--accent); }
.type-poster { border-left-color: #8b5cf6; }
.type-break { border-left-color: var(--line); background: var(--bg-alt); }
.type-break .t-title { color: var(--ink-soft); font-weight: 600; }
.type-open, .type-close { border-left-color: var(--ink); }

/* ---------------- Organizers ---------------- */
.org-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.org-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 22px; box-shadow: var(--shadow-sm); transition: transform 0.15s ease, box-shadow 0.2s ease;
}
.org-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.org-card h3 { margin: 14px 0 6px; font-size: 1.12rem; }
.org-card p { margin: 0; color: var(--ink-soft); font-size: 0.94rem; }
.avatar {
  display: inline-flex; align-items: center; justify-content: center;
  width: 54px; height: 54px; border-radius: 50%; font-family: var(--display);
  font-weight: 700; font-size: 1.15rem; color: #fff;
  background: linear-gradient(135deg, var(--brand), var(--accent-2));
}

/* ---------------- Location ---------------- */
.loc-grid { display: grid; grid-template-columns: 1.4fr 1fr; gap: 28px; align-items: stretch; }
.loc-map { border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); box-shadow: var(--shadow); min-height: 360px; }
.loc-map iframe { width: 100%; height: 100%; min-height: 360px; border: 0; display: block; }
.loc-info { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow-sm); }
.loc-info h3 { margin: 0 0 8px; font-size: 1.3rem; font-family: var(--display); }
.loc-info h4 { margin: 22px 0 6px; font-size: 1rem; }
.loc-addr { color: var(--ink-soft); margin: 0; }
.loc-info p { color: var(--ink-soft); }

/* ---------------- Footer ---------------- */
.footer { background: var(--ink); color: #cdd8e8; padding: 60px 0 34px; }
.footer .kicker { color: var(--accent); }
.partners { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin: 18px 0 30px; }
.partner {
  font-family: var(--display); font-weight: 600; font-size: 0.95rem; color: #eaf1fb;
  background: rgba(255, 255, 255, 0.06); border: 1px solid rgba(255, 255, 255, 0.14);
  padding: 10px 18px; border-radius: 10px;
}
.ack { max-width: 720px; margin: 0 auto 24px; text-align: center; color: #9fb0c9; font-size: 0.95rem; }
.ack strong { color: #fff; }
.copyright { text-align: center; color: #7e90ab; font-size: 0.86rem; margin: 0; padding-top: 20px; border-top: 1px solid rgba(255, 255, 255, 0.1); }

/* ---------------- Posters page ---------------- */
.subpage-hero { background: linear-gradient(170deg, var(--bg-hero), #fff 80%); padding: 64px 0 48px; border-bottom: 1px solid var(--line); }
.back-link { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; font-size: 0.92rem; margin-bottom: 16px; }
.info-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-top: 8px; }
.info-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; box-shadow: var(--shadow-sm); }
.info-card h3 { margin: 0 0 10px; font-family: var(--display); font-size: 1.15rem; }
.info-card p, .info-card li { color: var(--ink-soft); }
.info-card ul { margin: 0; padding-left: 20px; }
.info-card li { margin-bottom: 6px; }

/* ---------------- Responsive ---------------- */
@media (max-width: 860px) {
  .org-grid { grid-template-columns: repeat(2, 1fr); }
  .loc-grid { grid-template-columns: 1fr; }
  .facts { grid-template-columns: repeat(2, 1fr); }
  .info-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .nav-links {
    position: fixed; inset: 66px 0 auto 0; flex-direction: column; align-items: flex-start;
    gap: 0; background: #fff; border-bottom: 1px solid var(--line);
    padding: 8px 22px 18px; transform: translateY(-130%); transition: transform 0.3s ease;
    box-shadow: var(--shadow); max-height: calc(100vh - 66px); overflow-y: auto;
  }
  .nav-links.open { transform: translateY(0); }
  .nav-links a { width: 100%; padding: 13px 0; border-bottom: 1px solid var(--line); }
  .nav-cta { width: 100%; text-align: center; margin-top: 12px; padding: 12px; }
  .nav-cta, .nav-links a:last-child { border-bottom: 0; }
  .nav-toggle { display: flex; }
}

@media (max-width: 520px) {
  .section { padding: 56px 0; }
  .hero { padding: 64px 0 56px; }
  .facts { grid-template-columns: 1fr 1fr; }
  .org-grid { grid-template-columns: 1fr; }
  .t-item { grid-template-columns: 1fr; gap: 8px; }
  .t-time span { display: inline; }
  .btn { width: 100%; }
  .hero-actions { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; scroll-behavior: auto !important; transition: none !important; }
}