/* ==========================================================================
   SAR Doppler Tomography Research Whitepaper - Academic Design System
   Inspired by Academic Journal Publications, arXiv, and University Press
   ========================================================================== */

:root {
  /* Archival Paper Color Palette */
  --paper-bg: #fcfcfd;
  --paper-surface: #ffffff;
  --paper-elevated: #f8fafc;
  --paper-muted-bg: #f1f5f9;
  
  /* Academic Inks & Typography */
  --ink-primary: #0f172a;       /* Deep slate/black */
  --ink-secondary: #334155;     /* Body slate */
  --ink-muted: #64748b;         /* Captions, footnotes */
  --ink-dim: #94a3b8;           /* Subtle metadata */

  /* Hairline Borders */
  --border-subtle: #e2e8f0;
  --border-strong: #cbd5e1;
  --border-dark: #334155;

  /* Epistemic Badges (Separation of Facts, Data, Hypotheses) */
  --fact-bg: #f1f5f9;
  --fact-text: #0f172a;
  --fact-border: #94a3b8;

  --data-bg: #ecfdf5;
  --data-text: #065f46;
  --data-border: #6ee7b7;

  --hypo-bg: #fffbeb;
  --hypo-text: #92400e;
  --hypo-border: #fcd34d;

  /* Accent Ink */
  --accent-navy: #1e3a8a;
  --accent-blue: #0284c7;
  --accent-teal: #0f766e;
  --accent-amber: #d97706;
  --accent-rose: #be123c;

  /* Academic Typography */
  --font-serif: 'Newsreader', 'Georgia', 'Cambria', 'Times New Roman', serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;

  /* Dimensions */
  --sidebar-w: 280px;
  --content-w: 920px;
  --nav-h: 56px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 32px;
}

body {
  background-color: var(--paper-bg);
  color: var(--ink-secondary);
  font-family: var(--font-sans);
  line-height: 1.7;
  font-size: 15.5px;
  -webkit-font-smoothing: antialiased;
}

/* Academic Header Elements */
h1, h2, h3, h4, h5 {
  font-family: var(--font-serif);
  color: var(--ink-primary);
  font-weight: 600;
  line-height: 1.3;
}

h1 { font-size: 34px; letter-spacing: -0.01em; margin-bottom: 16px; font-weight: 700; }
h2 { font-size: 26px; margin-top: 48px; margin-bottom: 16px; padding-bottom: 8px; border-bottom: 1.5px solid var(--border-subtle); }
h3 { font-size: 20px; margin-top: 32px; margin-bottom: 12px; }
h4 { font-size: 16px; margin-top: 20px; margin-bottom: 8px; font-family: var(--font-sans); font-weight: 600; }

p {
  margin-bottom: 18px;
}

a {
  color: var(--accent-blue);
  text-decoration: none;
  border-bottom: 1px dotted rgba(2, 132, 199, 0.4);
  transition: all 0.15s ease;
}

a:hover {
  color: var(--accent-navy);
  border-bottom-style: solid;
}

code, .mono {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--paper-muted-bg);
  padding: 2px 6px;
  border-radius: 3px;
  border: 1px solid var(--border-subtle);
  color: var(--ink-primary);
}

/* ==========================================================================
   EPISTEMIC TRI-TAG SYSTEM
   ========================================================================== */
.tag-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  vertical-align: middle;
  margin-right: 6px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.03);
}

.tag-fact {
  background: var(--fact-bg);
  color: var(--fact-text);
  border: 1px solid var(--fact-border);
}

.tag-data {
  background: var(--data-bg);
  color: var(--data-text);
  border: 1px solid var(--data-border);
}

.tag-hypothesis {
  background: var(--hypo-bg);
  color: var(--hypo-text);
  border: 1px solid var(--hypo-border);
}

/* Callout Boxes */
.academic-callout {
  padding: 18px 22px;
  border-radius: var(--radius-md);
  margin: 24px 0;
  font-size: 14.5px;
  line-height: 1.6;
  border-left: 4px solid;
}

.academic-callout.fact-box {
  background: #f8fafc;
  border-left-color: var(--fact-border);
  border: 1px solid var(--border-subtle);
  border-left-width: 4px;
}

.academic-callout.data-box {
  background: #f0fdf4;
  border-left-color: var(--accent-teal);
  border: 1px solid #bbf7d0;
  border-left-width: 4px;
}

.academic-callout.hypothesis-box {
  background: #fefce8;
  border-left-color: var(--accent-amber);
  border: 1px solid #fef08a;
  border-left-width: 4px;
}

.callout-header {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 13.5px;
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ==========================================================================
   ACADEMIC LAYOUT WITH LEFT STICKY NAVIGATION PANE
   ========================================================================== */
.paper-wrapper {
  display: flex;
  max-width: 1380px;
  margin: 0 auto;
  min-height: 100vh;
}

/* Sticky Left Navigation Pane */
.paper-sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  padding: 32px 24px;
  border-right: 1px solid var(--border-subtle);
  background: var(--paper-surface);
  font-size: 13.5px;
}

.sidebar-title {
  font-family: var(--font-serif);
  font-size: 16px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-bottom: 4px;
}

.sidebar-meta {
  font-size: 11.5px;
  color: var(--ink-muted);
  margin-bottom: 24px;
  line-height: 1.4;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-subtle);
}

.sidebar-toc {
  list-style: none;
}

.sidebar-toc li {
  margin-bottom: 6px;
}

.sidebar-toc a {
  display: block;
  padding: 5px 8px;
  color: var(--ink-secondary);
  border-radius: var(--radius-sm);
  border-bottom: none;
  font-size: 13px;
  transition: all 0.15s ease;
}

.sidebar-toc a:hover,
.sidebar-toc a.active {
  background: var(--paper-muted-bg);
  color: var(--accent-navy);
  font-weight: 600;
  padding-left: 12px;
}

.sidebar-toc .toc-sub {
  padding-left: 16px;
  margin-top: 4px;
  font-size: 12px;
  list-style: none;
}

.sidebar-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 100%;
  margin-top: 24px;
  padding: 9px 12px;
  background: var(--accent-navy);
  color: #ffffff !important;
  font-size: 12.5px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: none;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.sidebar-btn:hover {
  background: var(--accent-blue);
  color: #ffffff;
}

/* Main Paper Content Column */
.paper-content {
  flex: 1;
  max-width: var(--content-w);
  padding: 48px 56px 96px 56px;
  background: var(--paper-bg);
}

/* Paper Header / Metadata Block */
.paper-header {
  margin-bottom: 40px;
  padding-bottom: 28px;
  border-bottom: 2px solid var(--ink-primary);
}

.paper-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-navy);
  background: rgba(30, 58, 138, 0.08);
  padding: 3px 8px;
  border-radius: 3px;
  margin-bottom: 12px;
}

.paper-authors {
  font-size: 14.5px;
  color: var(--ink-primary);
  font-weight: 500;
  margin-bottom: 8px;
}

.paper-affiliation {
  font-size: 12.5px;
  color: var(--ink-muted);
  font-style: italic;
  margin-bottom: 20px;
}

.paper-abstract {
  background: var(--paper-surface);
  border: 1px solid var(--border-subtle);
  border-left: 3px solid var(--accent-navy);
  padding: 20px 24px;
  border-radius: var(--radius-sm);
  margin-top: 20px;
  font-size: 14.5px;
  line-height: 1.65;
}

.abstract-title {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 12.5px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-navy);
  margin-bottom: 8px;
}

/* Stat Grid - Academic Clean */
.academic-stats-row {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px;
  margin: 32px 0;
}

.academic-stat-box {
  background: var(--paper-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 14px;
  text-align: center;
}

.stat-number {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 700;
  color: var(--ink-primary);
  line-height: 1.1;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 11px;
  color: var(--ink-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

/* ==========================================================================
   MONUMENT ILLUSTRATIONS & OPEN SOURCE FIGURES
   ========================================================================== */
.monument-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin: 32px 0;
}

.figure-card {
  background: var(--paper-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0,0,0,0.03);
}

.figure-img-wrap {
  width: 100%;
  height: 220px;
  background: #f1f5f9;
  position: relative;
  overflow: hidden;
}

.figure-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.25s ease;
}

.figure-card:hover .figure-img {
  transform: scale(1.02);
}

.figure-body {
  padding: 16px 18px;
}

.figure-title {
  font-size: 15.5px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-bottom: 6px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.figure-desc {
  font-size: 13px;
  color: var(--ink-secondary);
  line-height: 1.55;
  margin-bottom: 10px;
}

.figure-credit {
  font-size: 11px;
  color: var(--ink-dim);
  border-top: 1px solid var(--border-subtle);
  padding-top: 8px;
}

/* Full Width Figure (e.g. Zawyet T-Trench Barsanti 1904) */
.figure-full {
  background: var(--paper-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 16px;
  margin: 32px 0;
}

.figure-full img {
  width: 100%;
  max-height: 380px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
}

/* ==========================================================================
   ACADEMIC TABLES (Detection Matrix & Epoch Comparison)
   ========================================================================== */
.table-wrapper {
  overflow-x: auto;
  margin: 28px 0;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  background: var(--paper-surface);
}

.paper-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
  text-align: left;
}

.paper-table thead th {
  background: var(--paper-muted-bg);
  color: var(--ink-primary);
  font-weight: 700;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  padding: 12px 14px;
  border-bottom: 1.5px solid var(--border-strong);
  white-space: nowrap;
}

.paper-table tbody td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border-subtle);
  vertical-align: top;
  color: var(--ink-secondary);
}

.paper-table tbody tr:last-child td {
  border-bottom: none;
}

.paper-table tbody tr:hover {
  background: #f8fafc;
}

/* Table Precision & Status Badges */
.status-pill {
  display: inline-block;
  padding: 2px 7px;
  border-radius: 3px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
}

.status-detected {
  background: #ecfdf5;
  color: #065f46;
  border: 1px solid #a7f3d0;
}

.status-partial {
  background: #fffbeb;
  color: #92400e;
  border: 1px solid #fde68a;
}

.status-missed {
  background: #fef2f2;
  color: #991b1b;
  border: 1px solid #fecaca;
}

.precision-dots {
  color: #0284c7;
  font-weight: 700;
  letter-spacing: 2px;
}

/* Embedded Map Frame */
.map-frame-box {
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  overflow: hidden;
  height: 540px;
  margin: 32px 0;
  position: relative;
  background: #090d16;
}

.map-frame-box iframe {
  width: 100%;
  height: 100%;
  border: none;
}

/* Paper Footer & References */
.paper-references {
  margin-top: 64px;
  padding-top: 32px;
  border-top: 1.5px solid var(--border-strong);
  font-size: 13.5px;
}

.ref-item {
  margin-bottom: 12px;
  padding-left: 28px;
  text-indent: -28px;
  line-height: 1.5;
  color: var(--ink-secondary);
}

/* Responsive */
@media (max-width: 1080px) {
  .academic-stats-row { grid-template-columns: repeat(3, 1fr); }
  .monument-grid { grid-template-columns: 1fr; }
}

@media (max-width: 860px) {
  .paper-wrapper { flex-direction: column; }
  .paper-sidebar { width: 100%; height: auto; position: relative; border-right: none; border-bottom: 1px solid var(--border-subtle); }
  .paper-content { padding: 32px 20px; }
  .academic-stats-row { grid-template-columns: 1fr 1fr; }
}