:root {
  --bg: #fafafa;
  --fg: #222;
  --accent: #1a73e8;
  --muted: #666;
  --border: #ddd;
  --code-bg: #f3f4f6;
  --table-stripe: #f7f7f7;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN",
               "Hiragino Sans", Meiryo, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
  font-size: 16px;
}
.container {
  max-width: 880px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}
.header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 12px;
  margin-bottom: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--muted);
}
.header a { color: var(--accent); text-decoration: none; }
.header a:hover { text-decoration: underline; }
h1, h2, h3, h4 { font-weight: 700; line-height: 1.3; }
h1 { font-size: 2em; margin-top: 0; border-bottom: 2px solid var(--fg); padding-bottom: 8px; }
h2 { font-size: 1.5em; margin-top: 2em; border-bottom: 1px solid var(--border); padding-bottom: 6px; }
h3 { font-size: 1.2em; margin-top: 1.6em; }
h4 { font-size: 1.05em; }
p, ul, ol { margin: 0.8em 0; }
ul, ol { padding-left: 1.6em; }
li { margin: 0.3em 0; }
strong { color: #c0392b; }
em { color: var(--muted); }
code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 3px;
  font-family: "SF Mono", Consolas, Monaco, monospace;
  font-size: 0.92em;
}
pre {
  background: var(--code-bg);
  padding: 14px 18px;
  border-radius: 6px;
  overflow-x: auto;
}
pre code { background: transparent; padding: 0; }
blockquote {
  border-left: 4px solid var(--accent);
  margin: 1em 0;
  padding: 8px 18px;
  background: #fff;
  color: var(--fg);
}
table {
  border-collapse: collapse;
  margin: 1.2em 0;
  width: 100%;
  font-size: 0.95em;
  background: #fff;
}
th, td {
  border: 1px solid var(--border);
  padding: 8px 12px;
  text-align: left;
}
th {
  background: var(--code-bg);
  font-weight: 700;
}
tr:nth-child(even) td { background: var(--table-stripe); }
hr { border: 0; border-top: 1px solid var(--border); margin: 2em 0; }
a { color: var(--accent); }
.footer {
  margin-top: 60px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  font-size: 12px;
  color: var(--muted);
  text-align: center;
}
@media (max-width: 640px) {
  .container { padding: 20px 14px 40px; }
  h1 { font-size: 1.5em; }
  table { font-size: 0.82em; }
  th, td { padding: 6px 8px; }
}