/* ============================================================
   THE J CONSTANT — paper stylesheet
   Monospace, dark, MIT-Media-Lab-lab-notebook aesthetic
   ============================================================ */

:root {
  --bg: #ffffff;
  --bg-panel: #f5f5f5;
  --fg: #0b0b0b;
  --fg-dim: #666666;
  --line: #000000;
  --accent: #0b0b0b;   /* standardised to black */
  --accent-2: #444444;
  --accent-3: #00000011;
  --mono: "JetBrains Mono", "SF Mono", "Space Mono", "IBM Plex Mono",
          "Roboto Mono", Consolas, "Courier New", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--mono);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.wrap {
  max-width: 880px;
  margin: 0 auto;
  padding: 48px 24px 120px;
}

/* ---------- Top header ---------- */
.masthead {
  border-bottom: 1px solid var(--line);
  padding-bottom: 28px;
  margin-bottom: 36px;
}

.masthead .kicker {
  color: var(--accent);
  letter-spacing: 0.25em;
  font-size: 12px;
  text-transform: uppercase;
}

.masthead h1 {
  font-size: 38px;
  margin: 14px 0 8px;
  letter-spacing: -0.01em;
}

.masthead .subtitle {
  color: var(--fg-dim);
  font-size: 14px;
  margin-bottom: 18px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  font-size: 12px;
  color: var(--fg-dim);
}

.meta strong { color: var(--fg); }

/* ---------- Hero image ---------- */
.hero {
  margin: 32px 0 48px;
  text-align: center;
}

.hero img {
  width: 100%;
  max-width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
}

.hero figcaption {
  font-size: 12px;
  color: var(--fg-dim);
  margin-top: 10px;
  text-align: left;
}

/* ---------- Table of contents ---------- */
.toc {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 18px 22px;
  margin: 32px 0 48px;
  font-size: 13px;
}

.toc .toc-title {
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.2em;
  font-size: 11px;
  margin-bottom: 10px;
}

.toc ol {
  margin: 0;
  padding-left: 1.4em;
  columns: 2;
  column-gap: 32px;
}

.toc li { margin-bottom: 6px; }
.toc a { color: var(--fg); text-decoration: none; border-bottom: 1px dotted var(--line); }
.toc a:hover { color: var(--accent); border-color: var(--accent); }

/* ---------- Sections ---------- */
section {
  margin: 64px 0;
}

section h2 {
  font-size: 22px;
  border-left: 3px solid var(--accent);
  padding-left: 14px;
  margin-bottom: 6px;
}

section h2 .num {
  color: var(--accent);
  margin-right: 10px;
}

section h3 {
  font-size: 16px;
  color: var(--fg);
  margin: 28px 0 10px;
}

section h3 .num {
  color: var(--fg-dim);
  margin-right: 8px;
}

.section-tag {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--fg-dim);
  margin-bottom: 18px;
  padding-left: 17px;
}

p { margin: 14px 0; }

a { color: var(--accent); }

strong { color: var(--fg); }

em { color: var(--fg-dim); font-style: italic; }

/* ---------- Formula blocks ---------- */
.formula {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent-2);
  border-radius: 4px;
  padding: 14px 18px;
  margin: 18px 0;
  font-size: 14px;
  overflow-x: auto;
  white-space: pre;
}

/* ---------- Figures ---------- */
figure {
  margin: 24px 0;
  text-align: center;
}

figure img, figure canvas {
  max-width: 100%;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: #000;
}

figcaption {
  font-size: 12px;
  color: var(--fg-dim);
  margin-top: 8px;
  text-align: left;
}

.figure-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

@media (max-width: 720px) {
  .figure-grid { grid-template-columns: 1fr; }
  .toc ol { columns: 1; }
}

/* ---------- Info / result boxes ---------- */
.infobox {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 12px 16px;
  font-size: 13px;
  margin: 16px 0;
}

.infobox .row {
  display: flex;
  justify-content: space-between;
  border-bottom: 1px dashed var(--line);
  padding: 4px 0;
}

.infobox .row:last-child { border-bottom: none; }
.infobox .row span:first-child { color: var(--fg-dim); }
.infobox .row span:last-child { color: var(--accent); font-weight: 600; }

/* ---------- J summary table ---------- */
table.jtable {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  margin: 18px 0;
}

table.jtable th, table.jtable td {
  border: 1px solid var(--line);
  padding: 8px 12px;
  text-align: left;
}

table.jtable th {
  background: var(--bg-panel);
  color: var(--accent);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 11px;
  letter-spacing: 0.08em;
}

table.jtable td.num { text-align: right; font-weight: 600; }
table.jtable tr:hover td { background: #181a1f; }

/* ---------- Live / canvas section ---------- */
.live-card {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 18px;
  margin: 24px 0;
}

.live-card .live-title {
  font-size: 13px;
  color: var(--fg);
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.live-card .live-readout {
  font-size: 12px;
  color: var(--accent);
}

.live-card canvas {
  display: block;
  width: 100%;
  height: auto;
  background: #000;
  border-radius: 4px;
  border: 1px solid var(--line);
}

.live-controls {
  margin-top: 10px;
  display: flex;
  gap: 10px;
  align-items: center;
}

.live-controls button {
  font-family: var(--mono);
  font-size: 12px;
  background: transparent;
  color: var(--fg);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 6px 14px;
  cursor: pointer;
}

.live-controls button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ---------- Footer ---------- */
footer {
  border-top: 1px solid #e5e7eb;
  margin-top: 48px;
  padding: 28px 0 48px;
  font-size: 13px;
  color: var(--fg-dim);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-copy { font-size: 12px; color: var(--fg-dim); }

.back-nav{display:inline-block;font-size:12px;letter-spacing:0.2em;text-transform:uppercase;text-decoration:none;color:var(--fg);border:1px solid var(--fg);padding:6px 12px;transition:background .15s ease,color .15s ease}
.back-nav:hover{background:var(--fg);color:var(--bg)}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  align-items: center;
}

.footer-links a {
  color: var(--fg-dim);
  text-decoration: none;
  transition: color .14s ease;
}

.footer-links a:hover { color: var(--fg); }

.pill {
  display: inline-block;
  border: 1px solid var(--line);
  border-radius: 100px;
  padding: 2px 10px;
  font-size: 11px;
  color: var(--fg-dim);
  margin-right: 6px;
}

.pill.accent { color: var(--accent); border-color: var(--accent); }

/* back to top */
.top-link {
  font-size: 12px;
  display: inline-block;
  margin-top: 24px;
  color: var(--fg-dim);
  text-decoration: none;
}
.top-link:hover { color: var(--accent); }