:root {
  --bg:#ffffff;
  --muted:#6b7280;
  --text:#0b0d12;
  --accent:#16a34a;
  --brand:#2563eb;
  --card:#ffffff;
  --stroke:#e5e7eb;
  --shadow:0 1px 2px rgba(0,0,0,.04), 0 8px 24px rgba(15,23,42,.06);
}

* { box-sizing:border-box }

html, body {
  margin:0;
  padding:0;
  background:var(--bg);
  color:var(--text);
  font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,Noto Sans;
  line-height:1.6;
}

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

.container {
  max-width:1100px;
  margin:0 auto;
  padding:16px;
}

.nav {
  position:sticky;
  top:0;
  background:rgba(255,255,255,.85);
  backdrop-filter:blur(8px);
  z-index:100;
  border-bottom:1px solid var(--stroke);
}
.nav-inner {
  display:flex;
  gap:16px;
  align-items:center;
  justify-content:space-between;
  padding:10px 0;
}

.btn {
  display:inline-block;
  padding:10px 14px;
  border:1px solid var(--stroke);
  border-radius:10px;
  color:var(--text);
  background:#ffffff;
  box-shadow:var(--shadow);
}
.btn:hover { background:#f8fafc }
.btn.primary {
  border-color:transparent;
  background:linear-gradient(135deg, #1e3a8a, #9333ea);
  color:#fff;
  font-weight:700;
  box-shadow:var(--shadow);
  margin:2px;
}

.badge {
  padding:3px 8px;
  border-radius:999px;
  background:#f8fafc;
  border:1px solid var(--stroke);
  font-size:12px;
  color:#374151;
}

.hero {
  padding:36px 0 6px;
  border-bottom:1px solid var(--stroke);
  background:
    radial-gradient(800px 300px at 20% -10%, rgba(37,99,235,.08), transparent),
    radial-gradient(700px 260px at 80% 0%, rgba(34,197,94,.08), transparent);
}
.hero h1 { text-align:center; margin:8px 0 10px }
.hero p.lead { color:#374151; max-width:900px }
.hero-fig {
  margin:10px 0;
  border:1px solid var(--stroke);
  border-radius:14px;
  overflow:hidden;
  background:var(--card);
  box-shadow:var(--shadow);
}

.row {
  display:grid;
  grid-template-columns:repeat(12,1fr);
  gap:12px;
}
.col-6 { grid-column:span 6 }
.col-12 { grid-column:span 12 }

.section {
  padding:16px 0;
  border-bottom:1px solid var(--stroke);
  background:var(--bg);
}

.card {
  background:var(--card);
  border:1px solid var(--stroke);
  border-radius:14px;
  padding:10px 12px;
  margin-top:4px;
  box-shadow:var(--shadow);
}

.fig {
  border:1px solid var(--stroke);
  border-radius:12px;
  overflow:hidden;
  background:#fff;
  box-shadow:var(--shadow);
  padding-bottom:16px;
}
.fig img { width:100%; display:block }

.caption { font-size:18px; color:black; margin-top:1px;  margin-bottom:2px; text-align:left }

.gallery {
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(240px,1fr));
  gap:12px;
}
.gallery.one-col { display:block }
.gallery.one-col .fig { margin-bottom:14px }
.gallery.one-col .fig img { width:100%; height:auto; display:block }

/* Visual Results force one per row */
#results .gallery { grid-template-columns:1fr !important }
#results .fig { margin-bottom:16px }
.fig .cap { color:#6b7280; font-size:14px; margin-top:6px }

footer {
  padding:32px 0;
  color:#6b7280;
  border-top:1px solid var(--stroke);
}

kbd {
  background:#f8fafc;
  border:1px solid var(--stroke);
  border-bottom-color:#e5e7eb;
  border-radius:6px;
  padding:2px 6px;
  font-weight:600;
}

@media (max-width:900px) {
  .col-6 { grid-column:span 12 }
  .hero h1 { text-align:center; margin:8px 0 10px }
}
@media (max-width:600px) {
  .logo-row img { height:80px; width:auto }
}

/* Hero content alignment */
.hero .container { text-align:center }
.hero .links { justify-content:center }
.authors { margin:12px auto 6px; color:#374151; text-align:center }
.affil { color:#475569; font-size:15px; margin-top:4px; text-align:center }

.logo-row {
  display:flex;
  gap:18px;
  align-items:center;
  justify-content:center;
  margin:16px 0;
}
.logo-row img { height:80px; width:auto }

.brand-wrap { display:flex; align-items:center; gap:10px }
.brand-logo { height:28px; width:28px }

.badge-row { text-align:left }

.nav .brand {
  display:block;
  font-weight:800;
  letter-spacing:.3px;
  font-size:30px;
  color:#1d4ed8;
}

/* Abstract paragraph justification */
#abstract p { text-align:justify; text-justify:inter-word; hyphens:auto }

/* Titles & headings */
h1 { font-weight:800 }
h2,h3,h4 { margin-top:12px; margin-bottom:6px; margin-left:10px }
.section h2 { margin:4px 0 6px }
.section .card h3 { margin:2px 0 6px }

.hl1 { color:#b45309; font-weight:inherit; background:none }
.hl2 { color:#7c3aed; font-weight:inherit; background:none }

.title-main {
  text-align:center;
  font-weight:400;
  font-size:56px;
  line-height:1.1;
  margin:10px 0 6px;
}
.title-sub {
  text-align:center;
  font-weight:400;
  font-size:28px;
  max-width:1200px;
  margin:0 auto 8px;
  line-height:1.3;
}
@media (max-width:900px) {
  .title-main { font-size:42px }
  .title-sub { font-size:22px }
}

/* Acknowledgements */
#acknowledgements .card { margin-top:12px }
#acknowledgements p { font-size:16.5px; line-height:1.7; color:#2b2b2b }

/* CTA buttons */
.cta-buttons {
  display:flex;
  justify-content:center;
  align-items:center;
  gap:14px;
  flex-wrap:wrap;
  margin:16px auto 4px;
}
.cta-buttons .btn { min-width:230px; text-align:center }

.cta-row {
  display:flex;
  gap:16px;
  flex-wrap:wrap;
  justify-content:center;
  margin:10px 0 6px;
}

/* Methodology spacing tweak */
#method h2 { margin-bottom:10px }
#method .card { padding-top:10px }

.math {
  font-family: 'Times New Roman', serif;
  font-style: normal;   /* bỏ in nghiêng */
  font-weight: 500;     /* đậm vừa phải, giống LaTeX */
}
.figure-note {
  text-align: justify;
  text-justify: inter-word;
  font-size: 18px;
  margin: 0 20px 10px 20px;
}