:root {
  --bg: #f6f5f1;
  --paper: #ffffff;
  --ink: #1d2329;
  --muted: #5d6670;
  --line: #d9d6cc;
  --accent: #1f5fa8;
  --draw: #1f5fa8;
  --draw-soft: #8fb0d6;
  --dim: #b4532a;
  --grid: rgba(31, 95, 168, 0.06);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14181d;
    --paper: #1b2027;
    --ink: #e4e7eb;
    --muted: #9aa4af;
    --line: #2d343d;
    --accent: #7fb2ec;
    --draw: #7fb2ec;
    --draw-soft: #40607f;
    --dim: #e39a74;
    --grid: rgba(127, 178, 236, 0.05);
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
}

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

.wrap { max-width: 860px; margin: 0 auto; padding: 0 20px; }

header.site {
  border-bottom: 1px solid var(--line);
  background: var(--paper);
}
header.site .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; flex-wrap: wrap; padding-top: 14px; padding-bottom: 14px;
}
.brand {
  display: flex; align-items: center; gap: 10px;
  color: var(--ink); text-decoration: none; font-weight: 600; letter-spacing: 0.02em;
}
.brand svg { width: 28px; height: 28px; }
nav a {
  color: var(--muted); text-decoration: none; margin-left: 18px; font-size: 15px;
}
nav a:first-child { margin-left: 0; }
nav a:hover, nav a[aria-current="page"] { color: var(--ink); }

main { padding: 40px 0 56px; }

h1, h2, h3 { line-height: 1.25; font-weight: 650; }
h1 { font-size: 34px; margin: 0 0 12px; }
h2 { font-size: 23px; margin: 40px 0 12px; }
h3 { font-size: 18px; margin: 28px 0 8px; }

p.lead { font-size: 19px; color: var(--muted); max-width: 640px; margin-top: 0; }

.hero {
  display: grid; grid-template-columns: 1fr 220px; gap: 32px; align-items: center;
  padding-bottom: 24px; border-bottom: 1px solid var(--line);
}
.hero svg { width: 100%; height: auto; }

.notes-list { list-style: none; padding: 0; margin: 0; }
.notes-list li { padding: 16px 0; border-bottom: 1px solid var(--line); }
.notes-list a { font-size: 19px; font-weight: 600; text-decoration: none; }
.notes-list a:hover { text-decoration: underline; }
.notes-list p { margin: 4px 0 0; color: var(--muted); }

.meta, time { color: var(--muted); font-size: 14px; font-family: Consolas, "SF Mono", Menlo, monospace; }

.grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 20px;
}
figure.card {
  margin: 0; background: var(--paper); border: 1px solid var(--line); border-radius: 6px;
  overflow: hidden;
}
figure.card .sheet {
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 12px 12px;
  border-bottom: 1px solid var(--line);
  padding: 10px;
}
figure.card svg { display: block; width: 100%; height: auto; }
figure.card figcaption { padding: 12px 14px 14px; font-size: 15px; }
figure.card figcaption strong { display: block; font-size: 16px; }
figure.card figcaption span { color: var(--muted); }

figure.drawing {
  margin: 24px 0; padding: 14px; background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 12px 12px;
  border: 1px solid var(--line); border-radius: 6px;
}
figure.drawing svg { display: block; width: 100%; max-width: 520px; height: auto; margin: 0 auto; }
figure.drawing figcaption { text-align: center; color: var(--muted); font-size: 14px; margin-top: 8px; }

/* drawing strokes */
.d-main { fill: none; stroke: var(--draw); stroke-width: 1.6; stroke-linejoin: round; }
.d-thin { fill: none; stroke: var(--draw); stroke-width: 0.8; }
.d-center { fill: none; stroke: var(--draw-soft); stroke-width: 0.8; stroke-dasharray: 10 3 2 3; }
.d-hidden { fill: none; stroke: var(--draw-soft); stroke-width: 0.9; stroke-dasharray: 4 3; }
.d-dim { fill: none; stroke: var(--dim); stroke-width: 0.8; }
.d-fill { fill: var(--draw); fill-opacity: 0.08; stroke: var(--draw); stroke-width: 1.6; stroke-linejoin: round; }
.d-text { fill: var(--dim); font: 11px Consolas, "SF Mono", Menlo, monospace; }
.d-label { fill: var(--muted); font: 10px Consolas, "SF Mono", Menlo, monospace; }

article.note { max-width: 680px; }
article.note h1 { margin-bottom: 6px; }
article.note .meta { margin-bottom: 28px; display: block; }

table {
  border-collapse: collapse; width: 100%; margin: 16px 0; font-size: 15px;
  background: var(--paper);
}
th, td { border: 1px solid var(--line); padding: 7px 10px; text-align: left; }
th { font-weight: 600; }
td.num, th.num { text-align: right; font-family: Consolas, "SF Mono", Menlo, monospace; }
.table-scroll { overflow-x: auto; }

code, pre { font-family: Consolas, "SF Mono", Menlo, monospace; font-size: 15px; }
code { background: var(--paper); border: 1px solid var(--line); border-radius: 3px; padding: 0 4px; }
pre {
  background: var(--paper); border: 1px solid var(--line); border-radius: 6px;
  padding: 12px 14px; overflow-x: auto; line-height: 1.5;
}
pre code { border: 0; padding: 0; background: none; }

blockquote {
  margin: 20px 0; padding: 4px 16px; border-left: 3px solid var(--accent); color: var(--muted);
}

footer.site {
  border-top: 1px solid var(--line); padding: 22px 0 30px; color: var(--muted); font-size: 14px;
}
footer.site .wrap { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }

.not-found { text-align: center; padding: 40px 0; }
.not-found svg { width: 160px; height: auto; margin-bottom: 12px; }

@media (max-width: 640px) {
  body { font-size: 16px; }
  .wrap { padding: 0 16px; }
  h1 { font-size: 28px; }
  .hero { grid-template-columns: 1fr; }
  .hero svg { max-width: 180px; }
  nav a { margin-left: 14px; }
}