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/* Personal learning notebook: charcoal, ivory and electric chartreuse. */
:root{--ink:#222827;--muted:#646a68;--green:#303e37;--paper:#f4f4ef;--line:#d9ddd5;--serif:-apple-system,BlinkMacSystemFont,'Hiragino Kaku Gothic ProN',sans-serif}.sidebar{background:#202725;color:#ebeee8;border-right:0;width:220px;padding:38px 22px}.personal-heading{font-size:19px;font-weight:600;letter-spacing:.08em;padding:0 12px}.personal-heading small{display:block;font-size:9px;letter-spacing:2px;color:#a2afa5;margin-top:10px}.nav-label{color:#a2afa5}nav a{color:#c4cdc5;border-radius:3px}nav a.active{background:#d6ee85;color:#242d23}.side-note{border-color:#434d46;color:#d3ddd1}.side-note p,.sidebar-bottom{color:#a8b4aa}.shell{margin-left:220px}header{background:var(--paper);height:74px}.preview{border-radius:3px}h1{letter-spacing:-.03em;font-weight:600;font-size:36px}.eyebrow{font-size:10px;letter-spacing:2.4px;color:#60715a}.edition{font:11px/1.6 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/* Lesson reading and persistent progress */
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12px}.lesson-actions .text-button{font-size:11px}.os-instructions{padding:1px 15px}.official-actions a{width:100%}.download-link{font-size:11px;overflow-wrap:anywhere}.feature-copy p{line-height:2}footer span:last-child{margin-left:0}}

/* Concept lessons: paragraphs, scrollable tables, diagrams and answer reveals. */
.lesson-section p { line-height: 1.95; margin: 0 0 1em; overflow-wrap: anywhere; }
.lesson-section blockquote { margin: 1.25rem 0; padding: 1rem 1.25rem; background: #f2f3ec; border-left: 3px solid #557365; }
.lesson-section blockquote p:last-child { margin-bottom: 0; }
.lesson-table-wrap { max-width: 100%; overflow-x: auto; margin: 1.5rem 0; border: 1px solid #d9ddd4; border-radius: 8px; }
.lesson-table { width: 100%; border-collapse: collapse; font-size: .9rem; }
.lesson-table th,.lesson-table td { padding: .8rem; text-align: left; vertical-align: top; border-bottom: 1px solid #d9ddd4; min-width: 7rem; }
.lesson-table th { background: #eef1e9; font-weight: 600; }
.lesson-table tbody tr:last-child td { border-bottom: 0; }
.concept-diagram { margin: 1.5rem 0; padding: 1.2rem; border: 1px solid #d5dfd7; border-radius: 12px; background: #f6f8f4; }
.concept-diagram figcaption { font-size: .8rem; font-weight: 700; color: #456250; margin-bottom: 1rem; }
.concept-diagram ol { padding: 0; margin: 0; list-style: none; }
.concept-diagram li { display: grid; grid-template-columns: 1fr minmax(2rem,auto) 1fr; gap: .6rem; align-items: center; margin: .6rem 0; }
.diagram-node { background: white; padding: .7rem; border: 1px solid #cad7ce; border-radius: 8px; text-align: center; font-size: .85rem; overflow-wrap: anywhere; }
.diagram-arrow { color: #486651; display: flex; flex-direction: column; align-items: center; text-align: center; }
.diagram-arrow small { font-size: .7rem; max-width: 7rem; }
.answer-section { border: 1px solid #d9ddd4; padding: 1rem; border-radius: 8px; }
.answer-section summary { font-weight: 600; cursor: pointer; padding: .3rem 0; }
.answer-section[open] summary { margin-bottom: 1rem; }
@media(max-width:600px) { .concept-diagram { padding: .8rem; margin-inline: 0; } .concept-diagram li { gap: .3rem; } .diagram-node { padding: .6rem .4rem; font-size: .8rem; } }