:root {
  --primary-color: #000000;
  --text-color: #111111;
  --border-color: #999999;
  --bg-color: #ffffff;
  --code-bg: #f9f9f9;
}
body {
  font-family: Arial, sans-serif;
  color: var(--text-color);
  background-color: var(--bg-color);
  font-size: 1rem;
}
header {
  max-width: 960px;
  margin: 0 auto;
  padding: 20px;
  display: flex;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
}
nav a {
  color: var(--primary-color);
  text-decoration: none;
  padding: 6px 14px;
  border: 1px solid var(--primary-color);
  background: var(--bg-color);
}
.container {
  max-width: 900px;
  margin: 30px auto;
  padding: 0 20px;
}
h1 {
  font-size: 2rem;
  text-align: center;
  margin-bottom: 2rem;
}
h2 {
  font-size: 1.5rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}
h3 {
  font-size: 1.25rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}
p {
  margin-bottom: 1rem;
}
ul {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}
li {
  margin-bottom: 0.5rem;
}
li strong {
  color: var(--primary-color);
}
.code-box {
  background-color: var(--code-bg);
  border-left: 3px solid #666666;
  padding: 12px 15px;
  margin: 15px 0;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9rem;
  color: #111111;
  overflow-x: auto;
  border-radius: 4px;
  white-space: pre;
}
code {
  background-color: #f5f5f5;
  border: 1px solid #dddddd;
  padding: 2px 5px;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9em;
  border-radius: 3px;
  color: #000000;
}