:root {
  --fg: #1a2129;
  --muted: #5c6773;
  --bg: #fbfbf9;
  --surface: #ffffff;
  --accent: #2a5599;
  --accent-dark: #1e4079;
  --accent-tint: #eaf0fa;
  --grid: #d8dde3;
  --grid-soft: #e9ecf0;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-family: var(--sans);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

a { color: inherit; }

/* ---------- Header ---------- */

.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--grid);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  padding: 1.15rem 1.25rem;
}

.brand-group {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.brand {
  font-weight: 700;
  font-size: 1.3rem;
  color: var(--fg);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.brand .brand-mark {
  color: var(--accent);
  font-family: var(--mono);
  font-weight: 700;
  margin-right: 0.35rem;
}

.tagline {
  color: var(--muted);
  font-size: 0.9rem;
  font-family: var(--mono);
}

.nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.4rem 0.1rem;
  border-bottom: 2px solid transparent;
}

.nav a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ---------- Main ---------- */

main.wrap {
  padding-top: 2.25rem;
  padding-bottom: 3.5rem;
  min-height: 60vh;
}

/* ---------- Intro / hero ---------- */

.intro {
  margin-bottom: 2rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--grid);
}

.intro h1 {
  margin: 0 0 0.5rem 0;
  font-size: 1.9rem;
  letter-spacing: -0.01em;
}

.intro p {
  color: var(--muted);
  font-size: 1.05rem;
  max-width: 56ch;
  margin: 0;
}

.page-title {
  font-size: 1.7rem;
  margin: 0 0 1.5rem 0;
  letter-spacing: -0.01em;
}

/* ---------- Spreadsheet-style post list ---------- */

.sheet {
  border: 1px solid var(--grid);
  border-radius: 6px;
  overflow: hidden;
  background: var(--surface);
}

.sheet-head {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  padding: 0.55rem 1rem;
  background: var(--grid-soft);
  border-bottom: 1px solid var(--grid);
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

.post-summary {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: start;
  column-gap: 1.25rem;
  padding: 1.1rem 1rem;
  border-bottom: 1px solid var(--grid-soft);
  position: relative;
}

.post-summary:last-child {
  border-bottom: none;
}

.post-summary:hover {
  background: var(--accent-tint);
}

.post-summary .cell-main {
  min-width: 0;
}

.post-summary h2 {
  margin: 0 0 0.3rem 0;
  font-size: 1.12rem;
  line-height: 1.35;
}

.post-summary h2 a {
  color: var(--fg);
  text-decoration: none;
}

.post-summary:hover h2 a {
  color: var(--accent-dark);
}

.post-summary .excerpt {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.post-summary .cell-meta {
  text-align: right;
  white-space: nowrap;
  padding-top: 0.15rem;
}

.post-summary .date {
  display: block;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
}

/* Full-row link overlay so the whole row is clickable without nesting <a> */
.post-summary .row-link {
  position: absolute;
  inset: 0;
}

/* ---------- Tags ---------- */

.tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent-dark);
  background: var(--accent-tint);
  border: 1px solid var(--grid);
  border-radius: 3px;
  padding: 0.08rem 0.4rem;
  margin: 0.15rem 0.3rem 0.15rem 0;
}

.meta {
  color: var(--muted);
  font-size: 0.85rem;
  margin: 0 0 1.75rem 0;
  font-family: var(--mono);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--grid);
}

/* ---------- Single post ---------- */

article.post h1 {
  margin: 0 0 0.6rem 0;
  font-size: 1.85rem;
  letter-spacing: -0.01em;
  line-height: 1.25;
}

.content h2 {
  margin-top: 2.25rem;
  font-size: 1.35rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--grid);
}

.content h3 {
  margin-top: 1.75rem;
  font-size: 1.1rem;
}

.content p, .content li {
  font-size: 1rem;
}

.content pre {
  background: #1c2430;
  color: #e6e9ef;
  padding: 1rem 1.1rem;
  border-radius: 6px;
  overflow-x: auto;
  font-size: 0.88rem;
}

.content code {
  background: var(--grid-soft);
  border: 1px solid var(--grid);
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  font-size: 0.88em;
  font-family: var(--mono);
}

.content pre code {
  background: none;
  border: none;
  padding: 0;
}

.content a {
  color: var(--accent);
  text-decoration-color: var(--grid);
  text-underline-offset: 0.15em;
}

.content a:hover {
  color: var(--accent-dark);
}

/* Formula/spreadsheet tables get gridline treatment */
.content table {
  border-collapse: collapse;
  width: 100%;
  margin: 1.25rem 0;
  font-size: 0.92rem;
  border: 1px solid var(--grid);
}

.content th, .content td {
  border: 1px solid var(--grid);
  padding: 0.5rem 0.7rem;
  text-align: left;
}

.content th {
  background: var(--grid-soft);
  font-family: var(--mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.content tbody tr:nth-child(even) {
  background: #fafbfc;
}

.content blockquote {
  margin: 1.25rem 0;
  padding: 0.15rem 1rem;
  border-left: 3px solid var(--accent);
  background: var(--accent-tint);
  color: var(--fg);
}

.content blockquote p {
  margin: 0.6rem 0;
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--grid);
  background: var(--surface);
  padding: 1.5rem 0;
  color: var(--muted);
  font-size: 0.8rem;
}

.site-footer p {
  margin: 0.3rem 0;
}

.site-footer .fine-print {
  font-family: var(--mono);
  font-size: 0.72rem;
}

/* ---------- Responsive ---------- */

@media (max-width: 600px) {
  .wrap { padding: 0 1rem; }

  .site-header .wrap {
    padding: 1rem;
  }

  .intro h1 { font-size: 1.55rem; }

  .sheet-head { display: none; }

  .post-summary {
    grid-template-columns: 1fr;
    row-gap: 0.35rem;
    padding: 1rem 0.9rem;
  }

  .post-summary .cell-meta {
    text-align: left;
  }

  article.post h1 { font-size: 1.5rem; }

  .content table { font-size: 0.85rem; }
  .content th, .content td { padding: 0.4rem 0.5rem; }
}