/* style.css */
:root {
  --bg: #f8f9fa;
  --surface: #ffffff;
  --text: #1a1a1a;
  --text-secondary: #555;
  --primary: #0d6efd;
  --primary-hover: #0b5ed7;
  --border: #e9ecef;
  --code-bg: #f1f3f5;
  --radius: 8px;
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --max-width: 880px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

header.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
  position: sticky; top: 0; z-index: 10;
}
.site-nav { max-width: var(--max-width); margin: 0 auto; padding: 0 1rem; display: flex; align-items: center; justify-content: space-between; }
.site-logo { font-weight: 700; font-size: 1.25rem; color: var(--primary); text-decoration: none; }
.nav-links { display: flex; gap: 1rem; }
.nav-links a { color: var(--text-secondary); text-decoration: none; font-size: 0.95rem; }
.nav-links a:hover, .nav-links a.active { color: var(--primary); text-decoration: underline; }

main { max-width: var(--max-width); margin: 2rem auto; padding: 0 1rem; }

article { background: var(--surface); padding: 2rem; border-radius: var(--radius); box-shadow: var(--shadow); }
article h1 { font-size: 2rem; margin-bottom: 0.5rem; line-height: 1.3; }
.meta { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 1.5rem; display: flex; gap: 1rem; flex-wrap: wrap; }
.meta time, .meta .author, .meta .tag { display: inline-flex; align-items: center; gap: 0.3rem; }

nav#toc { background: var(--bg); padding: 1rem; border-radius: var(--radius); margin: 1.5rem 0; border: 1px solid var(--border); }
nav#toc h2 { font-size: 1rem; margin-bottom: 0.5rem; }
nav#toc ul { list-style: none; padding-left: 1rem; }
nav#toc li { margin: 0.4rem 0; }
nav#toc a { color: var(--primary); text-decoration: none; font-size: 0.95rem; }
nav#toc a:hover { text-decoration: underline; }

section { margin: 2rem 0; }
section h2 { font-size: 1.5rem; margin: 1.5rem 0 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--border); }
section h3 { font-size: 1.2rem; margin: 1.2rem 0 0.8rem; }
p { margin-bottom: 1rem; }
ul, ol { margin: 0 0 1rem 1.5rem; }
li { margin-bottom: 0.4rem; }

code { background: var(--code-bg); padding: 0.2em 0.4em; border-radius: 4px; font-family: var(--font-mono); font-size: 0.9em; }
pre { background: var(--code-bg); padding: 1rem; border-radius: var(--radius); overflow-x: auto; margin: 1rem 0; }
pre code { background: none; padding: 0; }

table { width: 100%; border-collapse: collapse; margin: 1rem 0; }
th, td { padding: 0.75rem; border: 1px solid var(--border); text-align: left; }
th { background: var(--bg); font-weight: 600; }

aside.series-nav {
  margin-top: 2rem; padding-top: 1.5rem; border-top: 1px solid var(--border);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 1rem;
}
aside.series-nav a { color: var(--primary); text-decoration: none; font-weight: 500; }
aside.series-nav a:hover { text-decoration: underline; }

footer { text-align: center; padding: 2rem 1rem; color: var(--text-secondary); font-size: 0.85rem; }

@media (max-width: 600px) {
  article { padding: 1.25rem; }
  article h1 { font-size: 1.6rem; }
  .nav-links { display: none; }
}