.lesson-page[data-chapter="4"] .hero-art{background-image:url('assets/chapter-4.webp');background-position:75% bottom;background-size:auto 150%}
.lesson-page[data-chapter="0"] .hero-art{background-image:url('assets/cover.webp');background-position:85% 82%;background-size:auto 180%;inset:0 0 0 30%}
.lesson-page[data-chapter="0"] .hero h1{max-width:710px}
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.royal-thread-grid article{border-top:2px solid #a5874d;padding:24px;background:#e7e3d5}
.royal-thread-grid h3{font-size:30px;line-height:1.3;margin:18px 0}
.royal-thread-grid p,.thread-deck{font-size:16px;line-height:1.85}
.royal-thread-grid a{display:inline-block;font-size:12px;color:#695124;text-decoration:underline;text-underline-offset:4px;margin-top:12px}
.introduction-method{background:#1d281d;color:#e7e6d8}
.method-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:45px;margin:35px 0}
.method-grid h3{font-size:30px;line-height:1.3;margin:20px 0}
.method-grid p,.argument-details p{font-size:16px;line-height:1.9;color:#c9d0bb}
.argument-details{border-top:1px solid #667354;border-bottom:1px solid #667354;padding:22px 0;margin:25px 0}
.argument-details summary{font:26px/1.5 var(--serif);color:#dec998;cursor:pointer}
.argument-details .text-button{color:#dec998;font-size:13px}
.introduction-method .research-section-actions a{color:#e3d3a8}
@media(max-width:800px){.royal-thread-grid{grid-template-columns:1fr}.method-grid{grid-template-columns:1fr;gap:12px}.lesson-page[data-chapter="4"] .hero-art{background-position:75% bottom;background-size:auto 150%}.lesson-page[data-chapter="0"] .hero-art{inset:0 0 0 15%;background-position:80% 85%}.royal-thread-grid article{padding:22px}}
