:root {
  --bg-page: #080c14;
  --bg-surface: #0f172a;
  --bg-surface-elevated: #162035;
  --bg-surface-highlight: #1e2c4a;
  --border-subtle: rgba(148, 163, 184, 0.12);
  --border-medium: rgba(148, 163, 184, 0.24);
  --border-active: rgba(56, 189, 248, 0.5);
  
  --ink-primary: #f8fafc;
  --ink-secondary: #94a3b8;
  --ink-muted: #64748b;
  
  --phosphor-cyan: #38bdf8;
  --phosphor-cyan-dim: rgba(56, 189, 248, 0.15);
  --ultraviolet: #a78bfa;
  --ultraviolet-dim: rgba(167, 139, 250, 0.15);
  --amber-alert: #f59e0b;
  --amber-dim: rgba(245, 158, 11, 0.15);
  --emerald-pass: #34d399;
  --emerald-dim: rgba(52, 211, 153, 0.15);
  
  --font-serif: "Newsreader", Charter, "Iowan Old Style", Georgia, serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Monaco, Consolas, monospace;
}

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

html {
  background-color: var(--bg-page);
  color: var(--ink-primary);
  font-family: var(--font-serif);
  font-size: 18px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  padding: 0;
  overflow-x: hidden;
  background: radial-gradient(circle at 50% 0%, #131d33 0%, #080c14 70%);
  min-height: 100vh;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.shell {
  max-width: 48rem;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.shell-wide {
  max-width: 64rem;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 1.5rem;
  max-width: 64rem;
  margin: 0 auto;
  border-bottom: 1px solid var(--border-subtle);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  letter-spacing: 0.02em;
}

.brand {
  color: var(--ink-primary);
  text-decoration: none;
  font-weight: 500;
}

.brand:hover {
  color: var(--phosphor-cyan);
}

.langsw {
  color: var(--ink-muted);
}

.langsw a {
  color: var(--ink-secondary);
  text-decoration: none;
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
}

.langsw a[aria-current="page"] {
  color: var(--phosphor-cyan);
  font-weight: 600;
  background: var(--phosphor-cyan-dim);
}

.langsw a:hover:not([aria-current="page"]) {
  color: var(--ink-primary);
}

/* Hero Section */
.hero {
  padding: 4.5rem 0 3rem;
  border-bottom: 1px solid var(--border-subtle);
}

.kicker {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--phosphor-cyan);
  margin: 0 0 1rem;
}

h1 {
  font-size: 2.75rem;
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 0 0 1.25rem;
  color: #ffffff;
}

@media (max-width: 640px) {
  h1 {
    font-size: 2.1rem;
  }
}

.standfirst {
  font-size: 1.22rem;
  line-height: 1.55;
  color: var(--ink-secondary);
  margin: 0 0 2.5rem;
}

/* Ledgerline (Key numbers) */
.ledgerline {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  padding: 1.5rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-medium);
  border-radius: 8px;
}

@media (max-width: 768px) {
  .ledgerline {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

.ledgerline [role="listitem"] {
  display: flex;
  flex-direction: column;
}

.ledgerline .n {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--phosphor-cyan);
  margin-bottom: 0.35rem;
  letter-spacing: -0.02em;
}

.ledgerline .l {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  line-height: 1.4;
  color: var(--ink-secondary);
}

/* Prose blocks */
.block {
  padding: 3.5rem 0;
}

.prose h2 {
  font-size: 1.75rem;
  font-weight: 600;
  line-height: 1.25;
  color: #ffffff;
  margin: 0 0 1.2rem;
  letter-spacing: -0.01em;
}

.prose p {
  margin: 0 0 1.35rem;
  color: #cbd5e1;
}

.prose strong {
  color: #ffffff;
  font-weight: 600;
}

.prose a {
  color: var(--phosphor-cyan);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.prose a:hover {
  color: #bae6fd;
}

.divider {
  border: 0;
  height: 1px;
  background: var(--border-subtle);
  margin: 0;
}

/* Interactive Simulator Section */
.instrument {
  padding: 4rem 0;
  background: linear-gradient(180deg, rgba(15, 23, 42, 0.6) 0%, rgba(8, 12, 20, 0.9) 100%);
  border-top: 1px solid var(--border-medium);
  border-bottom: 1px solid var(--border-medium);
}

.simulator-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-medium);
  border-radius: 10px;
  padding: 1.75rem;
  margin-top: 2rem;
  box-shadow: 0 20px 40px -15px rgba(0, 0, 0, 0.7);
}

.sim-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
  font-family: var(--font-mono);
  font-size: 0.82rem;
}

.sim-status {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--emerald-pass);
}

.sim-pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--emerald-pass);
  box-shadow: 0 0 8px var(--emerald-pass);
}

/* Sender inputs */
.sender-card {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}

.sender-card-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-secondary);
  margin: 0 0 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.input-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

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

.input-group label {
  display: block;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 0.4rem;
}

.label-overt {
  color: var(--phosphor-cyan);
}

.label-covert {
  color: var(--ultraviolet);
}

.input-group input[type="text"] {
  width: 100%;
  background: var(--bg-page);
  border: 1px solid var(--border-medium);
  border-radius: 6px;
  padding: 0.65rem 0.85rem;
  color: #ffffff;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.input-group input[type="text"]:focus {
  border-color: var(--phosphor-cyan);
  box-shadow: 0 0 0 2px var(--phosphor-cyan-dim);
}

.presets {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}

.preset-btn {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 4px;
  color: var(--ink-secondary);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.25rem 0.55rem;
  cursor: pointer;
  transition: all 0.15s;
}

.preset-btn:hover {
  background: var(--bg-surface-highlight);
  color: var(--ink-primary);
  border-color: var(--border-medium);
}

/* Network Wire Visualizer */
.wire-section {
  background: #05080e;
  border: 1px solid var(--border-medium);
  border-radius: 8px;
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}

.wire-title {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-muted);
  margin: 0 0 0.85rem;
  display: flex;
  justify-content: space-between;
}

.wire-byte-stream {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.6;
  word-break: break-all;
  background: rgba(0, 0, 0, 0.4);
  padding: 0.85rem;
  border-radius: 6px;
  border-left: 3px solid var(--phosphor-cyan);
}

.wire-byte-stream .chunk-dh {
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.1);
  padding: 1px 3px;
  border-radius: 3px;
}

.wire-byte-stream .chunk-mac {
  color: #a78bfa;
  background: rgba(167, 139, 250, 0.1);
  padding: 1px 3px;
  border-radius: 3px;
}

.wire-byte-stream .chunk-ct {
  color: #94a3b8;
}

.wire-legend {
  display: flex;
  gap: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}

.wire-legend span {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.wire-legend i {
  width: 10px;
  height: 10px;
  border-radius: 2px;
  display: inline-block;
}

.wire-legend i.dh { background: #38bdf8; }
.wire-legend i.mac { background: #a78bfa; }
.wire-legend i.ct { background: #94a3b8; }

/* Split Decryption Viewports */
.split-viewports {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

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

.viewport-card {
  background: var(--bg-surface-elevated);
  border-radius: 8px;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-medium);
  position: relative;
  overflow: hidden;
}

.viewport-card.surveillance {
  border-color: rgba(245, 158, 11, 0.35);
}

.viewport-card.bob {
  border-color: rgba(167, 139, 250, 0.35);
}

.viewport-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
}

.viewport-card.surveillance::before {
  background: var(--amber-alert);
}

.viewport-card.bob::before {
  background: var(--ultraviolet);
}

.vp-header {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.vp-tag-law {
  color: var(--amber-alert);
  background: var(--amber-dim);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-size: 0.72rem;
}

.vp-tag-bob {
  color: var(--ultraviolet);
  background: var(--ultraviolet-dim);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-size: 0.72rem;
}

.vp-body {
  flex-grow: 1;
}

.decrypted-bubble {
  background: var(--bg-page);
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  padding: 0.85rem;
  margin-bottom: 0.85rem;
}

.bubble-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: 0.35rem;
  display: block;
}

.bubble-text-overt {
  font-size: 1.05rem;
  color: #ffffff;
  font-weight: 500;
}

.bubble-text-covert {
  font-size: 1.05rem;
  color: var(--ultraviolet);
  font-weight: 600;
}

.vp-telemetry {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  line-height: 1.5;
  color: var(--ink-secondary);
  background: rgba(0, 0, 0, 0.3);
  padding: 0.75rem;
  border-radius: 6px;
  border-top: 1px solid var(--border-subtle);
}

.vp-telemetry .status-ok {
  color: var(--emerald-pass);
  font-weight: 600;
}

.vp-telemetry .status-hidden {
  color: var(--ultraviolet);
  font-weight: 600;
}

/* Bit Inspector Tool */
.bit-inspector {
  margin-top: 2rem;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-medium);
  border-radius: 8px;
  padding: 1.25rem;
}

.inspector-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--phosphor-cyan);
  margin: 0 0 0.85rem;
}

.bit-matrix {
  display: flex;
  flex-wrap: wrap;
  gap: 3px;
  padding: 0.75rem;
  background: #05080e;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.bit-cell {
  width: 22px;
  height: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 2px;
  background: rgba(255, 255, 255, 0.05);
  color: var(--ink-muted);
  user-select: none;
  transition: all 0.1s;
}

.bit-cell.covert-bit {
  background: var(--ultraviolet-dim);
  color: var(--ultraviolet);
  font-weight: 700;
  box-shadow: inset 0 0 0 1px var(--ultraviolet);
}

.bit-cell.active-inspect {
  transform: scale(1.2);
  z-index: 2;
  box-shadow: 0 0 8px var(--phosphor-cyan);
}

/* Regime Comparison Matrix */
.regime-table-wrap {
  overflow-x: auto;
  margin: 2rem 0;
}

.regime-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  text-align: left;
}

.regime-table th, .regime-table td {
  padding: 1rem 1.15rem;
  border-bottom: 1px solid var(--border-subtle);
}

.regime-table th {
  background: var(--bg-surface);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-secondary);
}

.regime-table tr:hover td {
  background: var(--bg-surface-elevated);
}

.regime-table .tag-regime {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.2rem 0.45rem;
  border-radius: 4px;
  display: inline-block;
}

.tag-regime.reg-1 { background: rgba(56, 189, 248, 0.15); color: #38bdf8; }
.tag-regime.reg-2 { background: rgba(245, 158, 11, 0.15); color: #fbbf24; }
.tag-regime.reg-3 { background: rgba(167, 139, 250, 0.15); color: #a78bfa; }

/* Method and Sources Ledger */
.ledger {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-medium);
  padding: 3.5rem 0;
}

.ledger h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: #ffffff;
  margin: 0 0 1.5rem;
}

.srcrow {
  margin-bottom: 1.75rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--border-subtle);
}

.srcrow:last-child {
  border-bottom: 0;
  margin-bottom: 0;
  padding-bottom: 0;
}

.srcrow .tag {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--phosphor-cyan);
  margin: 0 0 0.5rem;
}

.srcrow p {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--ink-secondary);
  margin: 0 0 0.5rem;
}

.srcrow .meta {
  font-size: 0.85rem;
  color: var(--ink-muted);
}

/* Footer */
footer.site {
  border-top: 1px solid var(--border-subtle);
  padding: 2rem 0;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--ink-muted);
}

footer.site .shell {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

footer.site a {
  color: var(--ink-secondary);
  text-decoration: none;
}

footer.site a:hover {
  color: var(--phosphor-cyan);
}

.totop {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  background: var(--bg-surface-elevated);
  color: var(--ink-primary);
  border: 1px solid var(--border-medium);
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 1.1rem;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
  transition: all 0.2s;
  z-index: 50;
}

.totop:hover {
  background: var(--bg-surface-highlight);
  color: var(--phosphor-cyan);
  border-color: var(--phosphor-cyan);
}