:root{--ink:#213e35;--muted:#68766c;--paper:#f7f7f0;--surface:#fff;--line:#dce3d9;--accent:#b96829;--green:#275e46;--soft:#edf2e8;--radius:12px;font-family:system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--paper);font-size:16px;line-height:1.65}*{box-sizing:border-box}body{margin:0}a{color:var(--green);text-decoration:none}a:hover{text-decoration:underline}button,input,textarea,select{font:inherit}button,a,input,textarea,select,summary{outline-offset:4px}button{cursor:pointer}button:disabled{opacity:.45;cursor:default}[hidden]{display:none!important}.site-header{max-width:1240px;padding:26px 40px;margin:auto;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:24px}.brand{display:flex;align-items:center;gap:14px;color:var(--ink);font-size:21px;font-weight:750;line-height:1.3}.brand:hover{text-decoration:none}.brand 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.muted{margin-top:18px}.actions{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.button{display:inline-flex;align-items:center;justify-content:center;gap:20px;background:var(--green);color:#fff;border:1px solid var(--green);padding:12px 20px;border-radius:7px;font-size:14px;font-weight:650;text-decoration:none;line-height:1.5}.button:hover{background:#1d4936;text-decoration:none}.secondary{background:transparent;color:var(--ink);border-color:#bdcbbb}.secondary:hover{background:var(--soft)}.hero-circuit{border:1px solid var(--line);background:#fff;box-shadow:0 14px 40px #243f3510;border-radius:var(--radius);padding:18px;transform:rotate(-1deg)}.schematic{width:100%;height:auto;display:block}.circuit-caption{display:block;text-align:center;color:var(--muted);font-size:13px;border-top:1px solid var(--line);padding:15px 0 0;margin-top:8px}.principles{display:grid;grid-template-columns:repeat(3,1fr);padding:30px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);gap:35px}.principles article{padding-right:20px}.number{font-family:ui-monospace,monospace;color:var(--accent);font-size:13px;display:block;margin-bottom:15px}.principles h2{font-size:23px}.principles p{font-size:15px;color:var(--muted);margin:0}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:20px;margin:45px 0 24px}.section-heading .eyebrow{margin-bottom:10px}.section-heading h2{margin:0}.lesson-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.lesson-card{background:var(--surface);padding:27px;border:1px solid var(--line);border-radius:var(--radius);color:var(--ink);display:block}.lesson-card:hover{border-color:var(--green);text-decoration:none}.lesson-card p{color:var(--muted);font-size:15px}.lesson-card .eyebrow{margin-bottom:14px}.lesson-card>span:last-child{font-size:13px;font-weight:700}.page-heading{margin:48px 0 35px}.page-heading h1{font-size:clamp(32px,4vw,46px)}.page-heading>p{max-width:720px;color:var(--muted)}.course-section{margin:35px 0}.course-list{border:1px solid var(--line);border-radius:var(--radius);background:#fff;overflow:hidden}.course-list>a{display:flex;gap:25px;align-items:center;padding:26px;border-bottom:1px solid var(--line);color:var(--ink)}.course-list>a:last-child{border-bottom:0}.course-list>a:hover{background:var(--soft);text-decoration:none}.course-list h3{font-size:21px;margin:0 0 7px}.course-list p{font-size:14px;color:var(--muted);margin:0}.course-list .number{margin:0}.course-list>a>span:last-child{margin-left:auto}.lesson{max-width:820px;margin:auto;padding-top:36px}.lesson .page-heading{margin-top:25px}.lesson .lead{font-size:19px}.lesson h2{margin-top:42px}.lesson p{font-size:18px;line-height:1.85}.lesson code{background:var(--soft);padding:2px 5px;border-radius:3px;font-size:.9em}figure{margin:30px 0}figure img{display:block;max-width:100%;height:auto;border-radius:8px}figcaption{font-size:14px;text-align:center;color:var(--muted);padding:12px}.diagram-figure{border:1px solid var(--line);background:#fff;border-radius:var(--radius);overflow:hidden}.self-check{padding:28px;border-radius:var(--radius);border:1px solid #cfdcbd;background:var(--soft);margin:35px 0}.self-check .eyebrow{margin-bottom:15px}.self-check details{margin-top:18px}.self-check summary{cursor:pointer;color:var(--green);font-weight:700;list-style-position:inside}.self-check details p{margin:15px 0 0}.lesson-navigation{max-width:820px;margin:45px auto 0;display:flex;justify-content:space-between;gap:20px}.back-link{font-size:14px}.panel,.block-card{border:1px solid var(--line);border-radius:var(--radius);padding:28px;background:var(--surface)}.narrow{max-width:650px;margin:60px auto}.notice{padding:15px 20px;background:var(--soft);border-left:3px solid var(--green);margin:24px 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11px;border-radius:5px;color:var(--ink);font-size:13px}.metadata{display:grid;grid-template-columns:1fr 1fr;gap:20px}.metadata .full{grid-column:1/-1}label{display:block;font-size:14px;font-weight:600}input,textarea,select{display:block;width:100%;background:#fff;border:1px solid #bdcbbb;border-radius:6px;padding:10px;color:var(--ink);margin-top:7px}textarea{resize:vertical;line-height:1.7}.block-card{margin:18px 0}.block-card label{margin-top:20px}.block-heading{display:flex;justify-content:space-between;align-items:center;gap:15px}.block-heading .actions{gap:6px}.block-toolbar{display:flex;flex-wrap:wrap;gap:10px;padding:20px 0}.save-bar{position:sticky;bottom:0;padding:20px;background:#f7f7f0f5;border-top:1px solid var(--line);display:flex;justify-content:space-between;align-items:center;gap:20px;z-index:5}.save-bar>span{font-size:13px;color:var(--muted)}.diagram-preview{background:#fff;border:1px solid var(--line);margin:20px 0;border-radius:6px}.upload-preview{max-height:250px;max-width:100%;margin:20px 0}dialog{width:min(1280px,96vw);max-height:94vh;overflow:auto;border:1px solid var(--line);border-radius:14px;background:var(--paper);color:var(--ink);padding:26px}dialog::backdrop{background:#18392fd0}.dialog-heading{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}.dialog-heading h2{margin:0}.dialog-heading .eyebrow{margin-bottom:7px}.diagram-toolbar{display:flex;flex-wrap:wrap;gap:10px;align-items:end}.diagram-toolbar label{font-size:12px;min-width:120px}.diagram-toolbar select{font-size:13px}.diagram-toolbar button{padding:11px}.diagram-workspace{display:grid;grid-template-columns:1fr 220px;gap:20px;margin:20px 0}.diagram-workspace aside{padding:15px;background:var(--soft);border-radius:8px}.diagram-workspace aside label{margin-bottom:20px;font-size:12px}#diagram-canvas{border:1px solid var(--line);touch-action:none;min-width:0;align-self:start}#diagram-canvas svg{user-select:none}#diagram-canvas [data-kind]{cursor:pointer}footer{max-width:1160px;margin:30px auto 0;padding:25px 32px 40px;border-top:1px solid var(--line);display:flex;gap:20px;justify-content:space-between;color:var(--muted);font-size:12px}.skip{position:absolute;left:20px;top:-100px;background:#fff;padding:15px;z-index:100}.skip:focus{top:15px}@media(max-width:850px){.hero{gap:30px;grid-template-columns:1fr;padding:45px 0}.hero-circuit{max-width:650px;transform:none}.lesson-grid{grid-template-columns:1fr 1fr}.site-header{padding:22px 24px}.diagram-workspace{grid-template-columns:1fr}.diagram-workspace aside{display:grid;grid-template-columns:1fr 1fr;gap:15px}.save-bar{flex-direction:column;align-items:start}.manage-card{flex-direction:column}.manage-actions{flex-direction:row;flex-wrap:wrap}.site-header nav{gap:12px}}@media(max-width:550px){main{padding:0 20px 40px}.site-header{align-items:start;flex-direction:column;gap:15px}.brand{font-size:20px}.principles{grid-template-columns:1fr;gap:25px}.principles article{display:grid;grid-template-columns:30px 1fr;gap:5px 10px}.principles p{grid-column:2}.principles h2,.principles .number{margin:0}.lesson-grid{grid-template-columns:1fr}.section-heading{align-items:start;flex-direction:column}.metadata{grid-template-columns:1fr}.block-heading{align-items:start;flex-direction:column}.panel,.block-card,.self-check{padding:20px}.course-list>a{padding:20px;gap:15px}.lesson p{font-size:17px}.diagram-workspace aside{grid-template-columns:1fr}footer{flex-direction:column}.lesson-navigation{flex-wrap:wrap}}@media print{.site-header nav,footer,.lesson-navigation,.back-link,.save-bar{display:none}body{background:#fff}main{max-width:none;padding:0}.lesson{max-width:none}.self-check details{display:block}.self-check details>summary{display:none}.self-check details>*{display:block}figure,.self-check{break-inside:avoid}}

/* Lesson tables and instructor table blocks. */
.lesson-table-scroll{overflow-x:auto;margin:30px 0;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface)}
.lesson-table{width:100%;min-width:400px;border-collapse:collapse;text-align:left;font-size:16px;line-height:1.65}
.lesson-table caption{text-align:left;font-weight:700;font-size:17px;padding:16px 20px;background:var(--surface);color:var(--ink);caption-side:top;border-bottom:1px solid var(--line)}
.lesson-table th{background:var(--green);color:#fff;font-weight:650;vertical-align:top}
.lesson-table th,.lesson-table td{padding:15px 20px;border-bottom:1px solid var(--line);overflow-wrap:normal;word-break:normal;hyphens:none}
.lesson-table td{vertical-align:top;border-right:1px solid var(--line)}
.lesson-table td:last-child{border-right:0}.lesson-table tbody tr:nth-child(even){background:#f1f5ed}.lesson-table tbody tr:last-child td{border-bottom:0}
.table-header-toggle{display:flex;align-items:center;gap:10px;margin:18px 0}.table-header-toggle input{width:auto;margin:0;accent-color:var(--green)}
.table-editor-scroll{overflow-x:auto;margin:18px 0;border:1px solid var(--line);border-radius:8px}
.table-editor{width:100%;border-collapse:collapse;font-size:13px}.table-editor th,.table-editor td{padding:10px;border-bottom:1px solid var(--line);border-right:1px solid var(--line);vertical-align:top}
.table-editor th{background:var(--soft);text-align:left;white-space:nowrap}.table-editor td:last-child{min-width:110px}.table-editor textarea{min-width:145px;margin:0;font-size:14px;font-weight:400;padding:9px;line-height:1.5}.table-editor .table-heading-row{background:#f1f5ed}.table-editor .table-heading-row textarea{font-weight:650}.table-controls{margin-top:15px}
.table-editor textarea{overflow-wrap:normal;word-break:normal;hyphens:none}
@media(max-width:550px){.lesson-table{font-size:14px}.lesson-table th,.lesson-table td{padding:12px 14px}}
@media print{.lesson-table-scroll{overflow:visible;break-inside:auto}.lesson-table{min-width:0;font-size:12px}.lesson-table thead{display:table-header-group}.lesson-table tr{break-inside:avoid}.lesson-table th{background:#edf2e8;color:#213e35}}