/* Responsive images */
img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1rem auto;
}

body {
  max-width: 960px;
  margin: 2rem auto;
  padding: 0 1rem;
  background-color: #f9f9fb;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: #2c3e50;
}

/* Header, main, footer spacing */
header, main, footer {
  margin-bottom: 2rem;
}

header h1 {
  margin-bottom: 0.5rem;
}

/* Footer */
footer {
  text-align: center;
  color: #888;
  font-size: 0.9rem;
  border-top: 1px solid #ddd;
  padding-top: 1rem;
  margin-top: 3rem;
}

/* Buttons for interactivity */
button {
  background-color: #3498db;
  color: white;
  border: none;
  padding: 0.6rem 1.2rem;
  font-size: 1rem;
  border-radius: 5px;
  cursor: pointer;
  margin-top: 1rem;
  transition: background-color 0.2s ease;
}

button:hover {
  background-color: #2c80b4;
}

/* Table styling */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}

th, td {
  border: 1px solid #ccc;
  padding: 0.6rem;
  text-align: left;
}

th {
  background-color: #f0f7fb;
  color: #2c3e50;
}

/* Quiz correct/incorrect feedback */
.correct {
  color: green;
  font-weight: bold;
}

.incorrect {
  color: red;
  font-weight: bold;
}

/* Responsive layout */
@media (max-width: 768px) {
  nav a {
    display: block;
    margin: 0.5rem 0;
  }

  table, thead, tbody, th, td, tr {
    display: block;
    width: 100%;
  }

  th {
    position: absolute;
    top: -9999px;
    left: -9999px;
  }

  td {
    border: none;
    position: relative;
    padding-left: 50%;
    text-align: right;
  }

  td::before {
    content: attr(data-label);
    position: absolute;
    left: 1rem;
    font-weight: bold;
    color: #333;
    text-align: left;
  }
}

/* Navigation styling */
.main-nav {
  background-color: #ecf6fc;
  padding: 1.5rem;
  border-left: 5px solid #3498db;
  margin: 2rem 0;
  border-radius: 8px;
}

.main-nav h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: #2c3e50;
}

.main-nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.main-nav li {
  margin: 0.5rem 0;
}

.main-nav a {
  color: #2c3e50;
  text-decoration: none;
  font-weight: bold;
  font-size: 1.05rem;
  display: inline-block;
  transition: all 0.2s ease;
}

.main-nav a:hover {
  color: #3498db;
  transform: translateX(4px);
}

/* Glossary terms */
dl {
  margin-top: 2rem;
}

dt {
  font-weight: bold;
  margin-top: 1.2rem;
}

dd {
  margin-left: 1.5rem;
  margin-top: 0.3rem;
  color: #555;
  line-height: 1.5;
}

/* Base styles for code blocks */
pre {
  background-color: #f4f4f4;
  padding: 1rem;
  overflow-x: auto;
  border-left: 4px solid #3498db;
  border-radius: 6px;
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
  line-height: 1.5;
}

code {
  font-family: 'Courier New', Courier, monospace;
  color: #2c3e50;
  display: block;
  white-space: pre-wrap;
  word-break: break-word;
}

/* Optional: inline code style (if you ever use <code> inline) */
p code, li code, h2 code {
  background-color: #eef;
  padding: 0.2em 0.4em;
  border-radius: 4px;
  font-size: 0.95em;
  color: #2d3e50;
}

li code {
  display: inline-block;
}

.question { margin-bottom: 20px; padding: 15px; border-left: 4px solid #3498db; background: #f4f8fb; }
    button { background-color: #3498db; color: #fff; border: none; padding: 10px 20px; cursor: pointer; }
    button:hover { background-color: #2980b9; }
    #result { margin-top: 30px; font-weight: bold; font-size: 1.2em; }