/* Digital Observatory Design System — Think in Strokes, Not Pixels */
:root {
  --primary: #6dddff;
  --primary-dim: #00c3eb;
  --secondary: #a68cff;
  --secondary-container: #591adc;
  --bg: #0b0e14;
  --surface: #161a21;
  --surface-high: #1c2028;
  --surface-highest: #22262f;
  --on-surface: #ecedf6;
  --on-surface-muted: #a9abb3;
  --gradient: linear-gradient(135deg, #6dddff, #a68cff);
  --step-plan: #6dddff;
  --step-sketch: #a68cff;
  --step-inspect: #ffb347;
  --step-refine: #6dff9f;
  --radius: 0.375rem;
  --font-heading: 'Space Grotesk', system-ui, sans-serif;
  --font-body: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--on-surface);
  line-height: 1.65;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Typography --- */
h1, h2, h3, h4 { font-family: var(--font-heading); }

.section-heading {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--on-surface);
  margin-bottom: 24px;
}

.subsection-heading {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--primary);
  margin: 36px 0 16px;
}

.inline-heading { display: inline; }

.gradient-text {
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

p { color: var(--on-surface-muted); margin-bottom: 16px; }

code, pre {
  font-family: var(--font-mono);
  font-size: 0.875em;
}

code {
  background: var(--surface-highest);
  padding: 2px 6px;
  border-radius: 3px;
  color: var(--primary);
}

/* --- Hero --- */
.hero {
  position: relative;
  min-height: 90vh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  z-index: 0;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, rgba(11,14,20,0.6) 0%, rgba(11,14,20,0.85) 60%, var(--bg) 100%);
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 80px 24px;
}

.hero-badges {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.chip {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  padding: 4px 12px;
  border-radius: 100px;
  border: 1px solid rgba(109, 221, 255, 0.3);
  color: var(--primary);
  background: rgba(109, 221, 255, 0.05);
}

.chip-accent {
  background: rgba(109, 221, 255, 0.12);
  border-color: var(--primary);
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 16px;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--on-surface);
  margin-bottom: 20px;
}

.hero-authors {
  font-size: 0.9rem;
  color: var(--on-surface-muted);
  margin-bottom: 8px;
}

.hero-affiliations {
  font-size: 0.8rem;
  color: #6b6e78;
  margin-bottom: 32px;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 22px;
  border-radius: var(--radius);
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.2s ease;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--gradient);
  color: #0b0e14;
}

.btn-primary:hover {
  opacity: 0.9;
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(109, 221, 255, 0.25);
}

.btn-ghost {
  background: transparent;
  color: var(--on-surface);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.btn-ghost:hover {
  background: var(--surface-high);
}

/* --- Sections --- */
.section {
  padding: 80px 0;
}

.section:nth-child(even) {
  background: var(--surface);
}

/* --- Pipeline --- */
.pipeline-section {
  background: var(--surface) !important;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--on-surface-muted);
  margin-bottom: 48px;
  font-style: italic;
}

.pipeline-steps {
  display: flex;
  align-items: flex-start;
  gap: 0;
  flex-wrap: wrap;
}

.step-card {
  flex: 1;
  min-width: 180px;
  background: var(--surface-high);
  border-radius: var(--radius);
  padding: 24px;
  position: relative;
  transition: transform 0.2s ease;
}

.step-card:hover { transform: translateY(-2px); }

.step-plan { border-top: 2px solid var(--step-plan); }
.step-sketch { border-top: 2px solid var(--step-sketch); }
.step-inspect { border-top: 2px solid var(--step-inspect); }
.step-refine { border-top: 2px solid var(--step-refine); }

.step-badge {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--on-surface-muted);
  margin-bottom: 8px;
}

.step-plan .step-badge { color: var(--step-plan); }
.step-sketch .step-badge { color: var(--step-sketch); }
.step-inspect .step-badge { color: var(--step-inspect); }
.step-refine .step-badge { color: var(--step-refine); }

.step-label {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.step-plan .step-label { color: var(--step-plan); }
.step-sketch .step-label { color: var(--step-sketch); }
.step-inspect .step-label { color: var(--step-inspect); }
.step-refine .step-label { color: var(--step-refine); }

.step-desc {
  font-size: 0.85rem;
  color: var(--on-surface-muted);
  line-height: 1.5;
  margin: 0;
}

.step-arrow {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 36px 8px 0;
  font-size: 1.5rem;
  color: var(--primary);
  flex-shrink: 0;
}

/* --- Abstract --- */
.abstract-grid {
  display: grid;
  grid-template-columns: 3fr 2fr;
  gap: 40px;
  align-items: start;
}

@media (max-width: 768px) {
  .abstract-grid { grid-template-columns: 1fr; }
}

.glass-card {
  background: rgba(34, 38, 47, 0.5);
  backdrop-filter: blur(20px);
  border-radius: var(--radius);
  padding: 28px;
}

.glass-card h3 {
  font-size: 1rem;
  font-weight: 700;
  font-family: var(--font-heading);
  color: var(--primary);
  margin-bottom: 16px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-size: 0.8rem;
}

.contributions-list {
  list-style: none;
  padding: 0;
}

.contributions-list li {
  color: var(--on-surface-muted);
  font-size: 0.9rem;
  padding: 10px 0;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  display: flex;
  align-items: flex-start;
  gap: 10px;
}

.contributions-list li::before {
  content: '→';
  color: var(--primary);
  flex-shrink: 0;
  font-weight: 700;
}

/* --- Cards --- */
.card {
  background: var(--surface-high);
  border-radius: var(--radius);
  padding: 24px;
}

.accent-card {
  border-top: 2px solid var(--primary);
}

.intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-bottom: 40px;
}

@media (max-width: 640px) {
  .intro-grid { grid-template-columns: 1fr; }
}

.intro-card h3 {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  color: var(--on-surface);
  margin-bottom: 12px;
}

/* --- Figures --- */
.paper-figure {
  margin: 32px 0;
  background: var(--surface-highest);
  border-radius: var(--radius);
  overflow: hidden;
}

.paper-figure img {
  width: 100%;
  height: auto;
  display: block;
}

.paper-figure figcaption {
  padding: 16px 20px;
  font-size: 0.875rem;
  color: var(--on-surface-muted);
  line-height: 1.5;
  border-top: 1px solid rgba(255,255,255,0.05);
}

.gallery-figure img {
  max-height: 700px;
  object-fit: contain;
  background: var(--surface-highest);
}

/* --- Metrics --- */
.metrics-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin: 32px 0;
}

@media (max-width: 480px) {
  .metrics-grid { grid-template-columns: 1fr; }
}

.metric-card {
  text-align: center;
  padding: 32px 24px;
  border-top: 2px solid var(--primary);
}

.metric-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--on-surface-muted);
  margin-bottom: 12px;
}

.metric-value {
  font-family: var(--font-heading);
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1;
  margin-bottom: 8px;
}

.metric-delta {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  color: #6dff9f;
  margin-bottom: 4px;
}

.metric-context {
  font-size: 0.8rem;
  color: #6b6e78;
}

/* --- Conclusion --- */
.conclusion-metrics {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin: 24px 0;
}

.metric-chip {
  background: var(--surface-high);
  border-left: 3px solid var(--primary);
  padding: 10px 16px;
  border-radius: 0 var(--radius) var(--radius) 0;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--on-surface);
}

.metric-chip strong { color: var(--primary); }

/* --- BibTeX --- */
.bibtex-block {
  position: relative;
  background: var(--surface-highest);
  border-radius: var(--radius);
  padding: 24px;
}

.bibtex-block pre {
  font-size: 0.85rem;
  color: var(--on-surface-muted);
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
}

.copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  background: var(--surface);
  border: 1px solid rgba(109,221,255,0.2);
  color: var(--primary);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 4px 12px;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
}

.copy-btn:hover {
  background: rgba(109,221,255,0.1);
}

/* --- Collapsible --- */
.collapsible {
  border-radius: var(--radius);
  background: var(--surface-high);
  padding: 20px 24px;
}

.collapsible summary {
  cursor: pointer;
  list-style: none;
  user-select: none;
}

.collapsible summary::marker,
.collapsible summary::-webkit-details-marker { display: none; }

.collapsible summary .section-heading {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 0;
}

.collapsible summary .section-heading::after {
  content: '▾';
  font-size: 1rem;
  color: var(--primary);
  transition: transform 0.2s;
}

.collapsible[open] summary .section-heading::after {
  transform: rotate(180deg);
}

.collapsible-content {
  padding-top: 24px;
}

/* --- AI Explanation Components --- */
.flecto-note,
.flecto-callout,
.flecto-card,
.flecto-panel {
  position: relative;
  border-radius: var(--radius);
  margin: 24px 0;
  padding: 20px 24px;
}

.flecto-note::before,
.flecto-callout::before,
.flecto-card::before,
.flecto-panel::before {
  content: '🤖 AI explanation';
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #60a5fa;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 0.5em;
}

.flecto-note {
  background: var(--surface-highest);
  border-left: 3px solid var(--primary);
  font-size: 0.9rem;
}

.flecto-callout {
  background: rgba(109, 221, 255, 0.06);
  border: 1px solid rgba(109, 221, 255, 0.15);
}

.flecto-card {
  background: var(--surface-high);
  border: 1px solid rgba(255,255,255,0.06);
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.flecto-panel {
  background: var(--surface);
  border: 1px solid rgba(109,221,255,0.1);
  box-shadow: 0 8px 40px rgba(0,0,0,0.3);
}

/* --- Scroll Reveal --- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .reveal { transition: none; }
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .pipeline-steps { flex-direction: column; }
  .step-arrow { padding: 8px 0; transform: rotate(90deg); }
  .metrics-grid { grid-template-columns: 1fr; }
}