body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  margin: 0;
  background: #f5f3ef;
  color: #222;
}

.site-header {
  background: white;
  padding: 22px 36px 16px 36px;
  border-bottom: 1px solid #ddd;
}

.site-title a {
  font-size: 2rem;
  font-weight: 700;
  text-decoration: none;
  color: #111;
}

.top-nav {
  margin-top: 14px;
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.top-nav a {
  text-decoration: none;
  color: #444;
  font-size: 1rem;
}

.top-nav a:hover {
  text-decoration: underline;
}

.page-layout {
  display: flex;
  min-height: calc(100vh - 110px);
}

.sidebar {
  width: 250px;
  padding: 28px 24px;
  background: #faf9f7;
  border-right: 1px solid #ddd;
  box-sizing: border-box;
}

.sidebar h3 {
  margin-top: 0;
  font-size: 1.5rem;
}

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

.sidebar li {
  margin-bottom: 12px;
}

.sidebar a {
  text-decoration: none;
  color: #333;
}

.sidebar a:hover {
  text-decoration: underline;
}

.content {
  flex: 1;
  padding: 40px;
  background: #f7f8fa;
}

.content h1 {
  margin-top: 0;
  margin-bottom: 24px;
  font-size: 2.2rem;
}

.content img {
  max-width: 1000px;
  width: 100%;
  display: block;
  margin: 28px auto 0 auto;
  background: white;
  box-shadow: 0 4px 18px rgba(0,0,0,0.14);
}

.content p,
.content ul {
  max-width: 1000px;
}

@media (max-width: 900px) {
  .page-layout {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid #ddd;
  }

  .content {
    padding: 24px 18px 40px 18px;
  }

.search-wrap {
  position: relative;
  margin-top: 18px;
  max-width: 320px;
}

#search-box {
  width: 100%;
  padding: 10px 12px;
  font-size: 0.95rem;
  border: 1px solid #cfd6df;
  border-radius: 8px;
  background: white;
  color: #223;
  box-sizing: border-box;
}

#search-box:focus {
  outline: none;
  border-color: #7d91ad;
}

.search-results {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  background: white;
  border: 1px solid #cfd6df;
  border-radius: 8px;
  box-shadow: 0 8px 22px rgba(0,0,0,0.08);
  overflow: hidden;
  z-index: 50;
}

.search-result-item {
  display: block;
  padding: 10px 12px;
  text-decoration: none;
  color: #2d4a6d;
  font-size: 0.94rem;
  border-bottom: 1px solid #eef2f6;
}

.search-result-item:last-child {
  border-bottom: none;
}

.search-result-item:hover {
  background: #f4f7fb;
}

  .top-nav {
    gap: 14px;
  }
}

body {
  background: #f7f8fa;
  color: #222;
}

.sidebar {
  background: #e9edf2;
}

.site-title a {
  color: #2d4a6d;
}

.top-nav a {
  color: #2d4a6d;
  padding-bottom: 4px;
}

.top-nav a:hover {
  color: #1b314a;
}

.sidebar a {
  color: #2d4a6d;
}

.top-nav a.active {
  font-weight: 600;
  color: #1b314a;
}

.content h1,
.content p,
.content ul,
.content ol {
  max-width: 800px;
}

.topic-list,
.slide-list {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

/* topic spacing */
.topic-item + .topic-item {
  margin-top: 26px;
}

/* topic titles */
.topic-link {
  text-decoration: none;
  color: #2d4a6d;
  font-weight: 500;        /* softer than before */
  font-size: 1.12rem;      /* slightly larger */
  display: block;
}

.topic-link.active-topic {
  font-weight: 600;
  color: #1b314a;
}

/* slides under topic */
.slide-list {
  margin-top: 4px;
  margin-left: 48px;       /* more indentation */
}



/* slide titles */
.slide-list a {
  text-decoration: none;
  color: #5c6f8d;
  font-size: 0.84rem;   /* noticeably smaller */
  font-weight: 400;
  line-height: 1.35;
}

.slide-list a.active-slide {
  color: #1b314a;
  font-weight: 500;
}

.slide-list li {
  margin-bottom: 2px;
}

.search-wrap {
  position: relative;
  margin-top: 18px;
  max-width: 320px;
}

#search-box {
  width: 100%;
  padding: 10px 12px;
  font-size: 0.95rem;
  border: 1px solid #cfd6df;
  border-radius: 8px;
  background: white;
  color: #223;
  box-sizing: border-box;
}

#search-box:focus {
  outline: none;
  border-color: #7d91ad;
}

.search-results {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  background: white;
  border: 1px solid #cfd6df;
  border-radius: 8px;
  box-shadow: 0 8px 22px rgba(0,0,0,0.08);
  overflow: hidden;
  z-index: 50;
}

.search-result-item {
  display: block;
  padding: 10px 12px;
  text-decoration: none;
  color: #2d4a6d;
  font-size: 0.94rem;
  border-bottom: 1px solid #eef2f6;
}

.search-result-item:last-child {
  border-bottom: none;
}

.search-result-item:hover {
  background: #f4f7fb;
}

/* Section topic list spacing */

.main ul {
    margin-top: 14px;
}

ul li {
    margin-bottom: 16px;
}