:root {
  --bg: #0d1117;
  --bg-card: #161b22;
  --bg-card-hover: #1c2129;
  --border: #30363d;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --accent: #58a6ff;
  --accent-hover: #79c0ff;
  --green: #3fb950;
  --orange: #d29922;
  --red: #f85149;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover { color: var(--accent-hover); }

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* NAV */
nav {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(13, 17, 23, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  padding: 0.75rem 0;
}
nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
nav .logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
}
nav .nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}
nav .nav-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  transition: color 0.2s;
}
nav .nav-links a:hover { color: var(--text); }

/* HERO */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 6rem 2rem 4rem;
  background: radial-gradient(ellipse at top, #161b22 0%, var(--bg) 70%);
}
.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--text) 0%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero .authors {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}
.hero .date {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
}
.hero .abstract {
  max-width: 800px;
  margin: 0 auto 2.5rem;
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.7;
}
.hero .cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: all 0.2s;
  cursor: pointer;
  border: none;
}
.btn-primary {
  background: var(--accent);
  color: var(--bg);
}
.btn-primary:hover {
  background: var(--accent-hover);
  color: var(--bg);
}
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* SECTIONS */
section {
  padding: 5rem 0;
}
section h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}
section .section-subtitle {
  color: var(--text-muted);
  margin-bottom: 3rem;
  font-size: 1.05rem;
}

/* STATS */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-bottom: 2rem;
}
.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  text-align: center;
  transition: transform 0.2s, border-color 0.2s;
}
.stat-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}
.stat-card .number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1.2;
}
.stat-card .label {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* NARRATIVE RESULTS */
.narrative-block {
  display: flex;
  gap: 3rem;
  align-items: flex-start;
  margin-bottom: 5rem;
}
.narrative-block.reverse {
  flex-direction: row-reverse;
}
.narrative-block .narrative-img {
  flex: 0 0 55%;
  cursor: pointer;
}
.narrative-block .narrative-img img {
  width: 100%;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: #fff;
  padding: 0.5rem;
  transition: transform 0.2s, border-color 0.2s;
}
.narrative-block .narrative-img img:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}
.narrative-block .narrative-text {
  flex: 1;
}
.narrative-block .narrative-text h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--text);
}
.narrative-block .narrative-text p {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 1rem;
}
.narrative-block .narrative-text .highlight {
  color: var(--accent);
  font-weight: 600;
}
.narrative-divider {
  width: 60px;
  height: 2px;
  background: var(--border);
  margin: 0 auto 5rem;
}

/* SUPPLEMENTARY GRID */
.supplementary {
  margin-top: 3rem;
}
.supplementary h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}
.figures-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}
.figures-grid-2x2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}
.figure-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  transition: transform 0.2s, border-color 0.2s;
  cursor: pointer;
}
.figure-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}
.figure-card img {
  width: 100%;
  height: auto;
  display: block;
  background: #fff;
  padding: 0.5rem;
}
.figure-card .caption {
  padding: 1rem 1.25rem;
}
.figure-card .caption h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}
.figure-card .caption p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* TASKS */
.tasks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}
.task-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  transition: transform 0.2s, border-color 0.2s;
}
.task-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}
.task-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.task-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
}
.badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 99px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.badge-easy { background: rgba(63,185,80,0.15); color: var(--green); }
.badge-medium { background: rgba(210,153,34,0.15); color: var(--orange); }
.badge-hard { background: rgba(248,81,73,0.15); color: var(--red); }

/* PAPER SECTION */
.paper-section {
  display: flex;
  gap: 3rem;
  align-items: flex-start;
}
.paper-preview {
  flex: 0 0 300px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  transition: transform 0.2s;
}
.paper-preview:hover { transform: translateY(-3px); }
.paper-preview img {
  width: 100%;
  display: block;
}
.paper-cover {
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 3/4;
  background: linear-gradient(135deg, #1a1f2e 0%, #0d1117 100%);
  border: 1px solid var(--border);
}
.paper-cover-inner {
  text-align: center;
  padding: 2rem;
}
.paper-cover .paper-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent);
  display: block;
  margin-bottom: 1.5rem;
}
.paper-cover h4 {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 1rem;
  line-height: 1.3;
}
.paper-cover .paper-cover-authors {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 0.75rem;
}
.paper-cover .paper-cover-date {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}
.paper-pdf-badge {
  display: inline-block;
  background: var(--accent);
  color: var(--bg);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.3rem 0.8rem;
  border-radius: 6px;
  letter-spacing: 0.05em;
}
.paper-info {
  flex: 1;
}
.paper-info h3 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
}
.paper-info .abstract-text {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  margin-bottom: 1.5rem;
}
.paper-info .bibtex {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  font-family: 'SF Mono', 'Fira Code', monospace;
  font-size: 0.8rem;
  color: var(--text-muted);
  overflow-x: auto;
  white-space: pre;
  position: relative;
}
.copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: var(--border);
  border: none;
  color: var(--text-muted);
  padding: 0.3rem 0.6rem;
  border-radius: 6px;
  font-size: 0.75rem;
  cursor: pointer;
  transition: all 0.2s;
}
.copy-btn:hover {
  background: var(--accent);
  color: var(--bg);
}

/* LIGHTBOX */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 200;
  background: rgba(0,0,0,0.9);
  backdrop-filter: blur(8px);
  align-items: center;
  justify-content: center;
  cursor: zoom-out;
}
.lightbox.active { display: flex; }
.lightbox img {
  max-width: 95vw;
  max-height: 95vh;
  border-radius: 8px;
  background: #fff;
  padding: 1rem;
}

/* FOOTER */
footer {
  border-top: 1px solid var(--border);
  padding: 3rem 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}
footer .links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 1rem;
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .hero h1 { font-size: 2.2rem; }
  .hero .abstract { font-size: 0.95rem; }
  .figures-grid { grid-template-columns: 1fr; }
  .figures-grid-2x2 { grid-template-columns: 1fr; }
  .narrative-block, .narrative-block.reverse { flex-direction: column; }
  .narrative-block .narrative-img { flex: none; }
  .paper-section { flex-direction: column; }
  .paper-preview { flex: none; max-width: 300px; }
  nav .nav-links { gap: 1rem; }
  nav .nav-links a { font-size: 0.8rem; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }

}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.8rem; }
  .stats-grid { grid-template-columns: 1fr; }
  nav .nav-links { display: none; }
}