:root {
  --bg-color: #fafafa;
  --text-color: #333;
  --code-bg: #f4f4f4;
  --link-color: #0969da;
  --header-color: #24292f;
  --border-color: #d0d7de;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background: 
    linear-gradient(rgba(255,255,255,0.9), rgba(255,255,255,0.9)),
    url('bg-main.jpg');
  background-size: cover;
  background-attachment: fixed;
  padding: 2rem;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  background: white;
  padding: 2rem 3rem;
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

h1 { color: var(--header-color); font-size: 2rem; margin-bottom: 1.5rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--border-color); }
h2 { color: var(--header-color); font-size: 1.5rem; margin: 2rem 0 1rem; }
h3 { color: var(--header-color); font-size: 1.1rem; margin: 1.5rem 0 0.5rem; }
p { margin: 0.5rem 0; }
a { color: var(--link-color); text-decoration: none; }
a:hover { text-decoration: underline; }
code { background: var(--code-bg); padding: 0.2rem 0.4rem; border-radius: 4px; font-size: 0.9em; font-family: ui-monospace, SFMono-Regular, SF Mono, Menlo, Consolas, monospace; }
pre { background: var(--code-bg); padding: 1rem; border-radius: 6px; overflow-x: auto; margin: 0.5rem 0 1rem; }
pre code { background: none; padding: 0; }
ul, ol { margin: 0.5rem 0 1rem 1.5rem; }
li { margin: 0.25rem 0; }
section { margin-bottom: 1rem; }
table { border-collapse: collapse; width: 100%; margin: 1rem 0; }
th, td { border: 1px solid var(--border-color); padding: 0.5rem; text-align: left; }
th { background: var(--code-bg); }

/* リポジトリに戻るボタン */
.back-link { margin-top: 2rem; padding-top: 1rem; border-top: 1px solid var(--border-color); text-align: center; }
.back-link a { display: inline-flex; align-items: center; gap: 8px; padding: 10px 20px; background: #24292f; color: white; border-radius: 6px; font-size: 14px; }
.back-link a:hover { background: #444c56; text-decoration: none; }

@media (max-width: 600px) {
  body { padding: 1rem; }
  .container { padding: 1.5rem; }
}