:root {
  --blue: #2F3EEA;
  --blue-light: #eef0fd;
  --blue-mid: #c5cafc;
  --text: #1a1a2e;
  --muted: #555;
  --border: #dde0f7;
  --bg: #fff;
  --section-bg: #f8f9ff;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: Arial, 'Helvetica Neue', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

/* ── Header ── */
header {
  background: var(--bg);
  border-bottom: 3px solid var(--blue);
  padding: 3rem 1rem 2rem;
  text-align: center;
}

header .venue {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue);
  margin-bottom: 1rem;
}

header h1 {
  font-size: clamp(1.5rem, 3vw, 2.5rem);
  font-weight: 700;
  line-height: 1.25;
  max-width: 1000px;
  margin: 0 auto 1.5rem;
  color: var(--text);
}

header h1 em {
  font-style: italic;
  color: var(--blue);
}

.authors {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 1rem;
  color: var(--muted);
  max-width: 760px;
  margin: 0 auto 0.5rem;
}

.authors a {
  color: var(--blue);
  text-decoration: none;
  font-weight: 500;
}
.authors a:hover { text-decoration: underline; }

.affiliations {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.4rem;
}

/* ── Link buttons ── */
.links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  margin-top: 1.8rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1.2rem;
  border-radius: 6px;
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  border: 2px solid var(--blue);
  background: var(--bg);
  color: var(--blue);
}
.btn:hover {
  background: var(--blue);
  color: #fff;
}
.btn.primary {
  background: var(--blue);
  color: #fff;
}
.btn.primary:hover {
  background: #1c2ac0;
  border-color: #1c2ac0;
}

/* ── Layout ── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

section {
  padding: 3rem 0;
  border-bottom: 1px solid var(--border);
}

section:last-child { border-bottom: none; }

section.alt { background: var(--section-bg); }

section.alt .container-full {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1.25rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--blue);
  display: inline-block;
}

p { margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

/* ── Key results ── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.stat-card {
  background: var(--bg);
  border: 2px solid var(--blue-mid);
  border-radius: 10px;
  padding: 1.5rem 1rem;
  text-align: center;
}

.stat-number {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--blue);
  line-height: 1;
}

.stat-label {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 0.5rem;
  line-height: 1.35;
}

/* ── Contributions list ── */
.contrib-list {
  list-style: none;
  margin-top: 1rem;
}

.contrib-list li {
  display: flex;
  gap: 0.9rem;
  margin-bottom: 1rem;
  align-items: flex-start;
}

.contrib-num {
  flex-shrink: 0;
  width: 1.8rem;
  height: 1.8rem;
  background: var(--blue);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.85rem;
  font-weight: 700;
  margin-top: 0.1rem;
}

/* ── Figures ── */
.figure-block {
  margin: 2rem 0;
  text-align: center;
}

.figure-block img {
  max-width: 100%;
  border-radius: 6px;
  border: 1px solid var(--border);
}

.figure-caption {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.83rem;
  color: var(--muted);
  margin-top: 0.6rem;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.5;
  text-align: center;
}

.figure-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 2rem 0;
}

@media (max-width: 600px) {
  .figure-row { grid-template-columns: 1fr; }
}

.figure-row .figure-block { margin: 0; }

/* ── Interpolation grid ── */
.interp-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
  margin: 1.5rem 0;
}

.interp-grid img {
  width: 100%;
  border-radius: 4px;
  border: 1px solid var(--border);
}

.interp-label {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.75rem;
  color: var(--muted);
  text-align: center;
  margin-top: 0.25rem;
}

@media (max-width: 600px) {
  .interp-grid { grid-template-columns: 1fr 1fr; }
}

/* ── BibTeX ── */
.bibtex-block {
  background: #f4f5fe;
  border: 1px solid var(--blue-mid);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.85rem;
  line-height: 1.7;
  overflow-x: auto;
  white-space: pre;
  color: #222;
  position: relative;
}

.copy-btn {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: var(--blue);
  color: #fff;
  border: none;
  border-radius: 5px;
  padding: 0.3rem 0.8rem;
  font-size: 0.75rem;
  font-family: 'Helvetica Neue', Arial, sans-serif;
  cursor: pointer;
  font-weight: 600;
}
.copy-btn:hover { background: #1c2ac0; }

/* ── Footer ── */
footer {
  background: var(--section-bg);
  border-top: 2px solid var(--border);
  text-align: center;
  padding: 2rem 1rem;
  font-family: 'Helvetica Neue', Arial, sans-serif;
  font-size: 0.82rem;
  color: var(--muted);
}

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