/* Save this code as 'mth101-style.css' in the same folder as your HTML file */
:root {
  --primary-color: #0d6efd;
  --secondary-color: #6c757d;
  --background-color: #f8f9fa;
  --text-color: #212529;
  --border-color: #dee2e6;
  --card-background: #ffffff;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  margin: 0;
  padding: 0;
  background-color: var(--background-color);
  color: var(--text-color);
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2em;
}

.breadcrumb {
  margin-bottom: 2em;
}

.breadcrumb a {
  font-weight: 500;
  color: var(--primary-color);
  text-decoration: none;
  font-size: 1.1em;
}
.breadcrumb a:hover {
  text-decoration: underline;
}

header {
  text-align: center;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 2em;
  padding-bottom: 1.5em;
}

header h1 {
  font-size: 2.8em;
  margin-bottom: 0.25em;
}

header p {
  font-size: 1.1em;
  color: var(--secondary-color);
  max-width: 600px;
  margin: 0.5em auto;
}

#table-of-contents {
  background-color: var(--card-background);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5em 2em;
  margin-bottom: 3em;
}

.toc-list {
  list-style: none;
  padding-left: 0;
  margin: 0;
  columns: 2;
  -webkit-columns: 2;
  -moz-columns: 2;
}

.toc-list li {
  margin-bottom: 0.75em;
}

.toc-list a {
  text-decoration: none;
  color: var(--primary-color);
}
.toc-list a:hover {
  text-decoration: underline;
}

.module {
  background-color: var(--card-background);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5em 2em;
  margin-bottom: 2em;
  scroll-margin-top: 2em; /* Offset for in-page links */
}

.module h2 {
  font-size: 1.8em;
  margin-top: 0;
  color: var(--text-color);
  border-bottom: 1px solid #eee;
  padding-bottom: 0.5em;
  margin-bottom: 0.5em;
}

.study-time {
  font-style: italic;
  color: var(--secondary-color);
  margin-top: 0;
  margin-bottom: 1.5em;
  font-size: 0.9em;
}

.module ul {
  padding-left: 20px;
  margin-top: 0;
}

.module li {
  margin-bottom: 0.5em;
}