:root {
  --ink: #12263a;
  --muted: #52677b;
  --line: #d9e2ea;
  --accent: #1464a5;
  --accent-2: #d97706;
  --paper: #ffffff;
  --wash: #f4f7fa;
}
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--wash);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 18px;
  line-height: 1.72;
}
body > header, body > main, body > nav, body > footer {
  max-width: 980px;
  margin: 0 auto;
}
body > main, body > section, body > article {
  max-width: 980px;
  margin: 0 auto;
  background: var(--paper);
  padding: 4rem clamp(1.25rem, 4vw, 4.5rem);
  box-sizing: border-box;
}
body > header {
  background: linear-gradient(135deg, #0e2740 0%, #174f7b 68%, #2c75a8 100%);
  color: white;
  padding: 4.5rem clamp(1.25rem, 4vw, 4.5rem);
  box-sizing: border-box;
}
header h1 { color: white; margin-top: 0; }
header p { color: #dceaf5; }
h1, h2, h3 { color: var(--ink); line-height: 1.18; letter-spacing: -0.025em; }
h1 { font-size: clamp(2.5rem, 6vw, 4.6rem); margin: 0 0 0.8rem; }
h2 { font-size: clamp(1.75rem, 3.5vw, 2.55rem); margin: 3.4rem 0 1rem; border-top: 1px solid var(--line); padding-top: 2.3rem; }
h3 { font-size: 1.35rem; }
p { margin: 1rem 0 1.3rem; }
a { color: var(--accent); text-decoration-thickness: 0.1em; text-underline-offset: 0.16em; }
strong a, p > strong:first-child > a {
  display: inline-block;
  background: var(--accent);
  color: white;
  padding: 0.75rem 1.1rem;
  border-radius: 0.45rem;
  text-decoration: none;
  font-weight: 700;
}
img {
  display: block;
  width: 100%;
  height: auto;
  margin: 2rem auto 0.8rem;
  border: 1px solid var(--line);
  border-radius: 0.35rem;
  box-shadow: 0 8px 28px rgba(18, 38, 58, 0.09);
}
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.8rem 0 2.3rem;
  font-variant-numeric: tabular-nums;
}
th, td { padding: 0.7rem 0.85rem; border-bottom: 1px solid var(--line); }
th { text-align: left; background: #eef4f8; }
td:last-child, th:last-child { text-align: right; }
pre {
  overflow-x: auto;
  background: #0e2236;
  color: #e7f0f8;
  padding: 1.2rem 1.35rem;
  border-radius: 0.45rem;
  font-size: 0.87rem;
  line-height: 1.55;
}
code { font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace; }
blockquote {
  margin: 2rem 0;
  border-left: 4px solid var(--accent);
  padding: 0.4rem 1.4rem;
  color: var(--muted);
  background: #f4f8fb;
}
ul, ol { padding-left: 1.5rem; }
li { margin: 0.45rem 0; }
.MathJax { overflow-x: auto; overflow-y: hidden; max-width: 100%; }
@media (max-width: 700px) {
  body { font-size: 16px; }
  body > main, body > section, body > article { padding: 2rem 1.15rem; }
  body > header { padding: 3rem 1.15rem; }
  h2 { margin-top: 2.4rem; }
}
@media print {
  body { background: white; font-size: 11pt; }
  body > main, body > section, body > article { max-width: none; padding: 0; }
  a { color: inherit; }
  img { break-inside: avoid; box-shadow: none; }
  h2 { break-after: avoid; }
}