:root {
  --ink: #1d2521;
  --muted: #6d746f;
  --line: #dfe4e0;
  --soft: #f4f7f5;
  --accent: #17634f;
  --accent-soft: #e5f0eb;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.library-shell { width: min(1160px, calc(100% - 40px)); margin: 0 auto; }
.hero { min-height: 64vh; padding: 28px 0 74px; border-bottom: 1px solid var(--line); }
.nav { display: flex; align-items: center; gap: 12px; }
.monogram { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; background: var(--accent); color: #fff; font: 700 18px Georgia, serif; }
.brand { font-size: 13px; font-weight: 650; letter-spacing: .05em; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(280px, .8fr); align-items: center; gap: 60px; padding-top: clamp(70px, 10vw, 130px); }
.eyebrow { margin: 0 0 20px; color: var(--accent); font-size: 11px; font-weight: 750; letter-spacing: .18em; }
h1 { margin: 0; max-width: 760px; font: 500 clamp(44px, 7vw, 76px)/1.08 Georgia, "Times New Roman", serif; letter-spacing: -.04em; }
.intro { max-width: 610px; margin: 28px 0 34px; color: var(--muted); font-size: 16px; line-height: 1.8; }
.browse-link, .start-link { color: var(--accent); font-weight: 700; text-decoration: none; }
.browse-link { padding-bottom: 5px; border-bottom: 1px solid var(--accent); }
.soundmark { display: flex; justify-content: center; align-items: center; gap: 8px; height: 220px; border-left: 1px solid var(--line); }
.soundmark span { width: 5px; height: var(--h); border-radius: 10px; background: var(--accent); opacity: calc(.3 + var(--h) / 240); }

.collection { padding: 72px 0 96px; }
.section-head { display: flex; justify-content: space-between; align-items: end; gap: 24px; margin-bottom: 34px; }
.section-head h2 { margin: 0; font: 500 clamp(30px, 4vw, 45px) Georgia, serif; }
#library-count { color: var(--muted); font-size: 13px; }
.lesson-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); border-top: 1px solid var(--ink); }
.lesson-card { position: relative; display: grid; grid-template-columns: 58px 1fr; gap: 18px; min-height: 260px; padding: 30px 28px 28px 0; border-bottom: 1px solid var(--line); }
.lesson-card:nth-child(odd) { padding-right: 38px; border-right: 1px solid var(--line); }
.lesson-card:nth-child(even) { padding-left: 38px; }
.card-number { color: var(--accent); font: 500 27px Georgia, serif; }
.card-label { margin: 1px 0 13px; color: var(--muted); font-size: 11px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
.card-copy h3 { margin: 0; font: 500 28px Georgia, serif; }
.card-summary { margin: 15px 0; color: var(--muted); line-height: 1.7; }
.card-meta { display: flex; flex-wrap: wrap; gap: 8px 18px; color: var(--muted); font-size: 12px; }
.card-meta span:last-child { color: var(--accent); }
.start-link { position: absolute; right: 28px; bottom: 28px; font-size: 14px; }
.lesson-card:nth-child(even) .start-link { right: 0; }

@media (max-width: 760px) {
  .hero-grid { grid-template-columns: 1fr; gap: 35px; }
  .soundmark { height: 100px; border-left: 0; border-top: 1px solid var(--line); }
  .lesson-grid { grid-template-columns: 1fr; }
  .lesson-card, .lesson-card:nth-child(odd), .lesson-card:nth-child(even) { padding: 26px 0 68px; border-right: 0; }
  .lesson-card:nth-child(even) .start-link { right: 0; }
}