/* Further reading. Shared tokens and the course header live in course.css. */
* { box-sizing: border-box; }
p, h1, h2, ol { margin: 0; }
ol { padding: 0; list-style: none; }
a { color: var(--ink); text-underline-offset: 3px; }

.reading { max-width: 760px; padding: 28px 20px 48px; font-family: var(--ui); }
.intro { font-size: 15px; line-height: 1.6; color: #3b463f; margin-bottom: 24px; }
.sources { display: grid; gap: 0; border-top: 1px solid var(--line); }
.source { padding: 16px 0; border-bottom: 1px solid var(--line); }
.source h2 { font-size: 16px; line-height: 1.35; font-weight: 500; }
.source cite { font-style: italic; }
.source h2 a { display: inline-block; padding: 4px 0; }
.byline { margin-top: 2px; font-size: 13px; line-height: 1.5; color: var(--muted); }
.free { margin-left: 6px; font-family: var(--mono); font-size: 12px; color: var(--ink); }
.use { margin-top: 6px; font-size: 14px; line-height: 1.6; max-width: 62ch; }

@media (max-width: 759px) {
  .reading { padding: 20px 16px 40px; }
  .source h2 a { min-height: 44px; display: inline-flex; align-items: center; }
}