/* ─── Google Fonts ─────────────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ─── Reset / Base ─────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: #1a1a2e;
  background: #ffffff;
}

/* ─── Typography ───────────────────────────────────────────── */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.25;
  color: #0f0f23;
}

p { margin-bottom: 1rem; }

a { color: #3273dc; transition: color 0.2s; }
a:hover { color: #1a5fb4; }

/* ─── Hero ─────────────────────────────────────────────────── */
.hero-section {
  background: linear-gradient(135deg, #0f0f23 0%, #1a1a4e 60%, #2d1b6e 100%);
  color: white;
  padding: 4rem 1.5rem 3.5rem;
  text-align: center;
}

.paper-title {
  font-size: clamp(1.6rem, 4vw, 2.6rem);
  font-weight: 700;
  color: #ffffff;
  max-width: 820px;
  margin: 0 auto 1rem;
  line-height: 1.2;
}

.venue-badge {
  display: inline-block;
  background: rgba(255,255,255,0.15);
  border: 1px solid rgba(255,255,255,0.35);
  color: #e8d5ff;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.3rem 0.9rem;
  border-radius: 20px;
  margin-bottom: 1.5rem;
}

.authors-block {
  font-size: 1rem;
  color: rgba(255,255,255,0.75);
  margin-bottom: 2rem;
}

.authors-block .author { margin: 0 0.4rem; }

.link-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
}

.btn-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.55rem 1.25rem;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.2s;
  border: 2px solid rgba(255,255,255,0.5);
  color: white;
  background: rgba(255,255,255,0.1);
}

.btn-link:hover {
  background: rgba(255,255,255,0.25);
  border-color: white;
  color: white;
}

.btn-link-disabled {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.55rem 1.25rem;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  border: 2px solid rgba(255,255,255,0.2);
  color: rgba(255,255,255,0.35);
  background: rgba(255,255,255,0.05);
  cursor: default;
}

/* ─── Section Layout ───────────────────────────────────────── */
.section {
  padding: 3.5rem 1.5rem;
}

.section-alt {
  background: #f8f9fc;
}

.container {
  max-width: 960px;
  margin: 0 auto;
}

.section-title {
  font-size: 1.7rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.4rem;
  color: #0f0f23;
}

.section-divider {
  width: 50px;
  height: 4px;
  background: linear-gradient(90deg, #6c3fc5, #3273dc);
  border-radius: 2px;
  margin: 0 auto 2.5rem;
}

/* ─── Abstract ─────────────────────────────────────────────── */
.abstract-text {
  font-size: 1rem;
  line-height: 1.75;
  color: #333;
  text-align: justify;
  max-width: 820px;
  margin: 0 auto;
}

/* ─── Teaser Video Section ─────────────────────────────────── */
.teaser-section {
  background: #0f0f23;
  padding: 2.5rem 1.5rem;
}

.teaser-video-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  max-width: 960px;
  margin: 0 auto 1rem;
}

.teaser-video-card {
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 24px rgba(0,0,0,0.5);
}

.teaser-video-card video {
  display: block;
  width: 100%;
  height: auto;
}

.teaser-caption {
  text-align: center;
  color: rgba(255,255,255,0.7);
  font-size: 0.95rem;
  max-width: 680px;
  margin: 0 auto;
  line-height: 1.6;
}

.teaser-caption strong { color: #d0b0ff; }

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

/* ─── PDF Embeds ───────────────────────────────────────────── */
.pdf-embed-wrap {
  width: 100%;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0,0,0,0.12);
  background: #eee;
  position: relative;
}

.pdf-embed-wrap object,
.pdf-embed-wrap iframe {
  display: block;
  width: 100%;
  border: none;
}

.pdf-fallback {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 2rem;
  font-size: 0.9rem;
  color: #555;
}

.figure-caption {
  text-align: center;
  font-size: 0.88rem;
  color: #555;
  margin-top: 0.75rem;
  line-height: 1.5;
  max-width: 820px;
  margin-left: auto;
  margin-right: auto;
}

/* ─── Image Grids ──────────────────────────────────────────── */
.img-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 0.75rem;
}

.img-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 0.75rem;
}

.img-card {
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(0,0,0,0.1);
  background: #f0f0f0;
}

.img-card img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.img-card .img-label {
  text-align: center;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.4rem 0.5rem;
  background: white;
  color: #333;
}

/* Colored labels for pendulum outcomes */
.label-blue   { color: #1e6fd9; }
.label-orange { color: #e07b00; }
.label-green  { color: #3a7d44; }
.label-gray   { color: #666; }

/* Vicsek temporal grid */
.vicsek-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 1rem;
}

.vicsek-col {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.vicsek-col .time-label {
  text-align: center;
  font-size: 0.82rem;
  font-weight: 600;
  color: #555;
}

.vicsek-col img {
  width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  display: block;
}

/* ─── Full-width figures ───────────────────────────────────── */
.figure-full {
  width: 100%;
  border-radius: 10px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
  margin-bottom: 0.75rem;
}

.figure-section-gap { margin-top: 2.5rem; }

/* ─── Video Players ────────────────────────────────────────── */
.video-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.video-card {
  background: #0f0f23;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}

.video-card video {
  display: block;
  width: 100%;
  height: auto;
}

.video-label {
  color: rgba(255,255,255,0.85);
  font-size: 0.88rem;
  font-weight: 600;
  text-align: center;
  padding: 0.6rem 0.75rem;
  background: rgba(255,255,255,0.06);
}

/* ─── BibTeX ───────────────────────────────────────────────── */
.bibtex-box {
  position: relative;
  background: #1e1e2e;
  border-radius: 10px;
  padding: 1.5rem 1.5rem 1rem;
  overflow: hidden;
}

.bibtex-box pre {
  color: #cdd6f4;
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 0.82rem;
  line-height: 1.6;
  margin: 0;
  overflow-x: auto;
  white-space: pre;
}

.copy-btn {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.25);
  color: rgba(255,255,255,0.8);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.3rem 0.75rem;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.copy-btn:hover { background: rgba(255,255,255,0.2); }
.copy-btn.copied { background: #3a7d44; border-color: #3a7d44; color: white; }

/* ─── Method Box ───────────────────────────────────────────── */
.method-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
  margin-top: 2rem;
}

.method-step {
  background: white;
  border-radius: 12px;
  padding: 1.25rem;
  box-shadow: 0 2px 12px rgba(0,0,0,0.07);
  border-top: 3px solid;
}

.method-step:nth-child(1) { border-color: #6c3fc5; }
.method-step:nth-child(2) { border-color: #3273dc; }
.method-step:nth-child(3) { border-color: #3a7d44; }

.step-num {
  font-size: 1.4rem;
  font-weight: 700;
  color: #aaa;
  margin-bottom: 0.4rem;
}

.method-step h4 { font-size: 0.95rem; margin-bottom: 0.4rem; }
.method-step p  { font-size: 0.85rem; color: #555; margin: 0; }

/* ─── Key Results callouts ─────────────────────────────────── */
.result-callout {
  background: linear-gradient(135deg, #f0e8ff 0%, #e8f0ff 100%);
  border-left: 4px solid #6c3fc5;
  border-radius: 0 10px 10px 0;
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  font-size: 0.95rem;
  color: #333;
}

/* ─── Footer ───────────────────────────────────────────────── */
.site-footer {
  background: #0f0f23;
  color: rgba(255,255,255,0.55);
  text-align: center;
  padding: 1.5rem;
  font-size: 0.85rem;
}

.site-footer a { color: rgba(255,255,255,0.75); }
.site-footer a:hover { color: white; }

/* ─── Responsive ───────────────────────────────────────────── */
@media (max-width: 768px) {
  .img-grid-4, .vicsek-grid { grid-template-columns: repeat(2, 1fr); }
  .img-grid-2, .video-grid, .method-steps { grid-template-columns: 1fr; }
  .paper-title { font-size: 1.5rem; }
}

@media (max-width: 480px) {
  .img-grid-4, .vicsek-grid { grid-template-columns: 1fr 1fr; }
}