body {
  font-family: "Hiragino Sans", "Yu Gothic", sans-serif;
  max-width: 800px;
  margin: 0 auto;
  padding: 16px;
  line-height: 1.7;
  color: #333;
  font-size: 16px;
}
h1 { font-size: 1.6em; border-bottom: 2px solid #333; padding-bottom: 8px; }
h2 { font-size: 1.3em; border-left: 4px solid #2196F3; padding-left: 12px; margin-top: 2em; }
h3 { font-size: 1.1em; margin-top: 1.5em; }
table { border-collapse: collapse; width: 100%; margin: 1em 0; font-size: 0.95em; }
th, td { border: 1px solid #ccc; padding: 8px; text-align: left; }
th { background: #f5f5f5; }
img { max-width: 100%; height: auto; margin: 1em 0; }
code { background: #f5f5f5; padding: 2px 6px; border-radius: 3px; }
pre { background: #f5f5f5; padding: 12px; overflow-x: auto; border-radius: 4px; }
hr { border: none; border-top: 1px solid #ddd; margin: 2em 0; }
blockquote { border-left: 3px solid #2196F3; margin-left: 0; padding-left: 16px; color: #555; }
.math { overflow-x: auto; }