/* Sidebar TOC for desktop screens */
@media screen and (min-width: 992px) {
  nav.toc {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    width: 300px;
    background-color: #f9f9f9;
    border-right: 1px solid #ccc;
    padding: 1em;
    overflow-y: auto;
    z-index: 1000;
    box-sizing: border-box;
  }

  main[role="main"] {
    margin-left: 320px;
    padding: 2em;
    box-sizing: border-box;
  }
}

/* TOC link styles */
nav.toc a {
  display: block;
  padding: 0.3em 0.5em;
  color: #0645ad;
  text-decoration: none;
  border-radius: 3px;
  transition: background-color 0.2s;
}

nav.toc a:hover {
  background-color: #f0f0f0;
}

nav.toc li.active > a {
  font-weight: bold;
  background-color: #e6f3ff;
}

/* TOC list structure */
nav.toc ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

nav.toc ul ul {
  padding-left: 1em;
  margin-top: 0.2em;
}

nav.toc li {
  margin-bottom: 0.2em;
}

/* Mobile fallback — show TOC above content */
@media (max-width: 991px) {
  nav.toc {
    position: static;
    width: auto;
    margin-bottom: 1em;
    border-right: none;
    border-bottom: 2px solid #ccc;
  }

  main[role="main"] {
    margin-left: 0;
  }
}

/* General body styles */
body {
  font-family: system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  margin: 0;
  padding: 0;
}

/* Main content area */
article[role="article"] {
  max-width: 800px;
  margin: 0 auto;
}

/* Headings */
h1.title.topictitle1 {
  font-size: 2.5em;
  color: #333;
  border-bottom: 2px solid #0645ad;
  padding-bottom: 0.5em;
  margin-bottom: 1em;
}

h2, h3, h4, h5, h6 {
  color: #444;
  margin-top: 1.5em;
  margin-bottom: 0.5em;
}

/* Paragraphs */
p {
  margin-bottom: 1em;
  text-align: justify;
}

/* Lists */
ol, ul {
  margin-top: 0.5em;
  margin-bottom: 1em;
  padding-left: 1.5em;
}

li {
  margin-bottom: 0.3em;
}

/* Short description */
p.shortdesc {
  font-style: italic;
  font-size: 1.1em;
  color: #666;
  border-left: 3px solid #0645ad;
  padding-left: 1em;
  margin: 1em 0;
}

/* DITA-OT-generated next/previous links */
nav.related-links {
  display: flex;
  justify-content: space-between;
  margin-top: 2em;
  padding-top: 1em;
  border-top: 1px solid #ccc;
}

nav.related-links a {
  background: #0645ad;
  color: #fff;
  padding: 0.5em 1em;
  text-decoration: none;
  border-radius: 4px;
  transition: background-color 0.2s ease;
}

nav.related-links a:hover {
  background-color: #042e7d;
}

/* Links */
a {
  color: #0645ad;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Optional: slightly increase spacing around main content */
main[role="main"] {
  padding-bottom: 3em;
}

/* Navigation buttons after content, aligned with text */
.lesson-nav {
  max-width: 800px;
  margin: 2em auto 0 auto;
  display: flex;
  justify-content: flex-start;
  gap: 1em;
  padding-top: 1em;
}

/* Individual nav buttons */
.nav-button {
  background-color: #000;
  color: #fff;
  padding: 0.6em 1.2em;
  text-decoration: none;
  border-radius: 4px;
  font-weight: bold;
  transition: background-color 0.2s ease;
  display: inline-block;
}

.nav-button:hover {
  background-color: #333;
}

/* Table grid and layout */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5em;
  font-size: 0.95em;
}

/* Table headers */
table thead {
  background-color: #f2f2f2; /* light gray header */
}

table th,
table td,
td.entry,
th.entry {
  border: 1px solid #ccc;
  padding: 0.6em;
  text-align: left;
  vertical-align: top;
}

thead tr > .entry {
  background-color: #f2f2f2;
  font-weight: bold;
}