.open-index { margin-block: var(--section-gap); scroll-margin-top: 2rem; }
.open-index-heading { max-width: 680px; margin-bottom: 2.5rem; }
.open-index-heading h2 { font-size: clamp(2rem, 3.5vw, 3rem); letter-spacing: -.025em; margin-block: 0 1rem; }
.open-index-heading .open-eyebrow { margin-bottom: 1rem; }
.open-chapter-grid { display: grid; grid-template-columns: repeat(12, minmax(0, 1fr)); gap: 1.5rem; }
.open-chapter-card { grid-column: span 5; display: flex; flex-direction: column; position: relative; min-height: 200px; padding: 2rem; border: 2px solid var(--gold); border-radius: 12px; background: var(--paper); box-shadow: var(--shadow); text-decoration: none; }
.open-chapter-card:nth-child(2n) { grid-column: span 7; }
.open-chapter-card:nth-child(3) { grid-column: span 8; }
.open-chapter-card:nth-child(4) { grid-column: span 4; }
.open-chapter-card:nth-child(7), .open-chapter-card:nth-child(11) { grid-column: span 7; }
.open-chapter-card:nth-child(8), .open-chapter-card:nth-child(12) { grid-column: span 5; }
.open-chapter-card:nth-child(4n + 2) { border-radius: 12px 48px 12px 12px; }
.open-chapter-card:nth-child(4n + 1) { border-radius: 12px 12px 12px 48px; }
.open-chapter-card h3 { font-size: 1.5rem; margin: .75rem 0 1rem; }
.open-chapter-card p { font-size: 1rem; max-width: 44ch; margin-bottom: 2rem; }
.open-chapter-part { color: var(--burgundy); font-family: var(--label); font-size: 1rem; font-weight: 500; }
.open-chapter-arrow { align-self: flex-end; margin-top: auto; font-size: 1.5rem; line-height: 1; color: var(--blue); }
.open-chapter-card-feature { min-height: 280px; background: var(--cream); padding-right: 25%; }
.open-chapter-card-feature::after { content: ''; position: absolute; width: 30%; height: 80%; bottom: 1rem; right: 1rem; background: url('/media/notebook-sprig.webp') center / contain no-repeat; pointer-events: none; }
.open-chapter-card-feature h3 { font-size: 2.25rem; }
.open-chapter-card-feature .open-chapter-arrow { margin-right: -30%; }
.open-chapter-card:hover { background-color: var(--cream); }
@media (max-width: 760px) {
  .open-chapter-grid { grid-template-columns: minmax(0, 1fr); gap: 1rem; }
  .open-chapter-card, .open-chapter-card:nth-child(n) { grid-column: 1; min-height: 184px; padding: 1.5rem; }
  .open-chapter-card-feature { padding-right: 1.5rem; }
  .open-chapter-card-feature::after { opacity: .2; }
  .open-chapter-card-feature h3 { font-size: 1.5rem; }
  .open-chapter-card-feature .open-chapter-arrow { margin-right: 0; }
}