/* mankinracing.com - /learn/ lesson pages. Extends css/style.css. */

body.learn { padding-top: 3.5rem; }

.nav-links a.active { color: var(--text); }

.learn-head {
  background: var(--bg-alt);
  border-bottom: 1px solid var(--line);
  padding: 3rem 0 2.25rem;
}

.learn-head h1 {
  font-size: clamp(1.9rem, 5vw, 3rem);
  font-weight: 800;
  max-width: 22em;
}

main.wrap { padding-top: 2.5rem; padding-bottom: 4rem; }

.lesson { max-width: 42em; }

.lesson p.meta {
  color: var(--muted);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1.5rem;
}

.lesson h2 {
  font-size: 1.35rem;
  margin: 2.5rem 0 0.9rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
}

.lesson h2:first-of-type { border-top: 0; padding-top: 0; }

.lesson p { margin-bottom: 1rem; }
.lesson strong { color: var(--text); }

.lesson ul, .lesson ol { padding-left: 1.4rem; margin-bottom: 1rem; }
.lesson li { margin-bottom: 0.6rem; }
.lesson li strong { color: var(--accent); font-weight: 700; }

/* conversion table */
.lesson table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.25rem 0 1.75rem;
  font-size: 0.95rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 4px;
}

.lesson th, .lesson td {
  text-align: left;
  padding: 0.55rem 0.8rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

.lesson th {
  color: var(--muted);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
}

.lesson tr:last-child td { border-bottom: 0; }
.lesson td:last-child { font-variant-numeric: tabular-nums; }

/* worksheet problems */
.lesson p.problem {
  background: var(--card);
  border-left: 3px solid var(--accent);
  border-radius: 0 4px 4px 0;
  padding: 0.9rem 1.1rem;
  margin: 0 0 0.9rem;
}

.lesson p.problem strong { color: var(--text); }

/* index list */
.lessons {
  list-style: none;
  padding: 0;
  margin: 2rem 0 0;
  border-top: 1px solid var(--line);
}

.lessons li { margin: 0; }

.lessons a {
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
  padding: 1rem 0.25rem;
  border-bottom: 1px solid var(--line);
  color: var(--text);
}

.lessons a:hover { text-decoration: none; background: var(--bg-alt); }

.lessons .num {
  color: var(--accent);
  font-weight: 800;
  font-family: "Arial Narrow", "Helvetica Neue", Arial, sans-serif;
  font-size: 1.4rem;
  min-width: 2.2rem;
}

.lessons .what {
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-family: "Arial Narrow", "Helvetica Neue", Arial, sans-serif;
  font-size: 1.1rem;
}

@media (max-width: 760px) {
  .learn-head { padding: 2rem 0 1.5rem; }
  .lesson table { font-size: 0.88rem; }
  .lesson th, .lesson td { padding: 0.45rem 0.55rem; }
}

/* back links - the site nav hides its links below 760px, so lesson
   pages carry their own way back */
.learn-head .section-kicker a { color: inherit; }
.learn-head .section-kicker a:hover { color: var(--text); text-decoration: none; }
.lesson p.back { margin-top: 2.5rem; padding-top: 1.25rem; border-top: 1px solid var(--line); }
.lesson p.back a { text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.85rem; font-weight: 700; }

/* addenda */
.lesson p.deeper { margin-top: 2.5rem; padding: 1rem 1.1rem; background: var(--card); border: 1px solid var(--line); border-radius: 4px; }
.lesson p.deeper span { display: block; color: var(--muted); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.08em; font-weight: 700; margin-bottom: 0.25rem; }
.lesson pre { background: var(--card); border: 1px solid var(--line); border-radius: 4px; padding: 0.9rem 1.1rem; overflow-x: auto; margin: 0 0 1rem; font-size: 0.92rem; line-height: 1.5; }
.lesson code { font-family: Menlo, Consolas, monospace; }
.lessons a.sub { padding: 0.5rem 0.25rem 0.9rem; border-bottom: 1px solid var(--line); }
.lessons a.sub .what { font-family: inherit; text-transform: none; letter-spacing: 0; font-weight: 400; font-size: 0.95rem; color: var(--muted); }
.lessons li a:not(.sub) + a.sub { margin-top: -1px; }
.lessons li:has(a.sub) > a:not(.sub) { border-bottom: 0; }

/* syllabus: only published lessons are links, and only links are red */
.syllabus li strong { color: var(--text); }
.syllabus li a.lesson-link strong { color: var(--accent); }
.syllabus li a.lesson-link:hover strong { text-decoration: underline; }
.syllabus ol { margin-bottom: 1.5rem; }

/* synthetic-data banner + charts + data links */
.lesson blockquote { margin: 0 0 1.5rem; padding: 0.9rem 1.1rem; border-left: 3px solid var(--muted); background: var(--card); border-radius: 0 4px 4px 0; color: var(--muted); font-size: 0.95rem; }
.lesson blockquote p { margin: 0; }
.lesson blockquote.synthetic { border-left-color: #e0a021; }
.lesson blockquote.synthetic strong { color: #e0a021; }
.lesson figure { margin: 1.25rem 0 1.5rem; }
.lesson figure img, .lesson p > img { width: 100%; height: auto; border: 1px solid var(--line); border-radius: 4px; display: block; }
.lesson figcaption { color: var(--muted); font-size: 0.85rem; margin-top: 0.4rem; }
.lesson a.data { font-family: Menlo, Consolas, monospace; font-size: 0.85rem; }

/* mechanisms track */
.lesson h2#mechanisms { margin-top: 3rem; font-size: 1.6rem; }
.lessons.mech .num { font-size: 1.1rem; min-width: 3rem; }
.lesson blockquote.math { border-left-color: #3b82f6; color: var(--text); }
.lesson blockquote.math strong { color: #3b82f6; }
.lesson blockquote.math p + p { margin-top: 0.6rem; }