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

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.7;
  color: #333;
  background-color: #f9f9fb;
  max-width: 900px;
  margin: 0 auto;
  padding: 20px;
}

header {
  text-align: center;
  margin-bottom: 30px;
  border-bottom: 2px solid #007acc;
  padding-bottom: 10px;
}

header h1 {
  color: #005a9c;
  font-size: 2.2em;
}

.intro blockquote {
  background-color: #eef7ff;
  border-left: 5px solid #007acc;
  padding: 15px 20px;
  margin: 20px 0;
  font-style: italic;
  color: #444;
}

.intro footer {
  text-align: right;
  font-size: 0.9em;
  margin-top: 10px;
  color: #666;
}

main section {
  margin-bottom: 40px;
}

h2 {
  color: #005a9c;
  border-bottom: 1px dashed #ccc;
  padding-bottom: 5px;
  margin-bottom: 20px;
}

h3 {
  color: #007acc;
  margin: 20px 0 10px;
}

h4 {
  color: #2c5aa0;
  margin: 15px 0 8px;
}

ul, ol {
  margin: 10px 0 10px 20px;
}

li {
  margin-bottom: 6px;
}

dl {
  margin: 15px 0;
}

dt {
  font-family: "Courier New", monospace;
  font-weight: bold;
  color: #d32f2f;
  margin-top: 10px;
}

dd {
  margin: 5px 0 10px 20px;
  color: #444;
}

code {
  font-family: "Courier New", Courier, monospace;
  background-color: #eee;
  color: #c7254e;
  padding: 2px 5px;
  border-radius: 3px;
  font-size: 0.95em;
}

pre {
  background-color: #272822;
  color: #f8f8f2;
  padding: 15px;
  border-radius: 5px;
  overflow-x: auto;
  margin: 15px 0;
  font-size: 0.95em;
}

pre code {
  background-color: transparent;
  color: inherit;
  padding: 0;
}

footer {
  text-align: center;
  margin-top: 50px;
  color: #777;
  font-size: 0.9em;
  border-top: 1px solid #ddd;
  padding-top: 20px;
}
img {
 max-width: 100%; 
 height: auto;
}