/* Lesson preview — Blueprint style */

html {
  font-size: 17px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  line-height: 1.65;
  max-width: 760px;
  margin: 0 auto;
  padding: 6rem 2rem 6rem;
  color: #1a1a1a;
  background: #fafaf8;
}

/* Top nav bar */
.lesson-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: #fff;
  border-bottom: 1px solid #e0e0dc;
  z-index: 100;
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
}

.nav-inner {
  max-width: 760px;
  margin: 0 auto;
  padding: 0.9rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.nav-title {
  font-weight: 700;
  font-size: 0.9rem;
  color: #444;
}

.nav-links {
  display: flex;
  gap: 0.4rem;
}

.nav-links a {
  display: inline-block;
  padding: 0.35rem 0.8rem;
  text-decoration: none;
  color: #444;
  background: #f0efea;
  border-radius: 4px;
  font-size: 0.85rem;
  font-weight: 600;
  transition: background 0.15s;
}

.nav-links a:hover {
  background: #e2e0d8;
}

.nav-links a.active {
  background: #b798ee;
  color: #fff;
}

h1 {
  font-size: 2.1rem;
  line-height: 1.2;
  margin-top: 0;
  margin-bottom: 1.5rem;
  font-weight: 700;
  color: #111;
}

h2 {
  font-size: 1.5rem;
  margin-top: 3rem;
  margin-bottom: 1rem;
  font-weight: 700;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid #e5e5e0;
  color: #111;
}

h3 {
  font-size: 1.15rem;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  font-weight: 700;
  color: #222;
}

p {
  margin: 0 0 1.1rem;
}

ul, ol {
  margin: 0 0 1.3rem;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.4rem;
}

blockquote {
  margin: 1.5rem 0;
  padding: 1rem 1.4rem;
  border-left: 4px solid #b798ee;
  background: #f7f4fb;
  border-radius: 0 6px 6px 0;
}

blockquote p:last-child {
  margin-bottom: 0;
}

table {
  border-collapse: collapse;
  margin: 1.5rem 0;
  width: 100%;
}

th, td {
  border: 1px solid #d8d8d4;
  padding: 0.6rem 0.9rem;
  text-align: left;
  vertical-align: top;
}

th {
  background: #f0efea;
  font-weight: 700;
}

code {
  background: #eee;
  padding: 0.1rem 0.3rem;
  border-radius: 3px;
  font-size: 0.9em;
}

a {
  color: #6b4cb8;
}

strong {
  font-weight: 700;
}

/* Highlight spans get a tiny bit of padding for readability */
span[style*="background-color"] {
  padding: 0.05rem 0.25rem;
  border-radius: 2px;
}