.lesson-body{max-width:1000px;padding-top:36px}.lesson-top h1{max-width:850px}.lesson-top{padding-bottom:40px}.lesson-top .back-link{margin-bottom:26px}.objective{border-left:4px solid var(--teal);background:#eaf6f3;padding:20px 24px;border-radius:0 10px 10px 0}.objective>strong{color:var(--teal)}.objective p{margin:6px 0 0}.lesson-section{margin-block:46px}.lesson-section h2{font-size:clamp(1.6rem,3vw,2.1rem)}.lesson-section h3{font-size:1.25rem;line-height:1.3}.concept-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.concept,.lesson-box{border:1px solid var(--line);border-radius:16px;background:var(--paper);padding:24px}.concept{display:flex;flex-direction:column}.concept-symbol{font-size:2rem;font-weight:800;color:var(--teal);display:block;margin-bottom:14px}.concept h3{margin-bottom:12px}.unit{font-weight:750;font-size:.93rem;display:block;margin-top:auto;padding-top:14px;border-top:1px solid var(--line)}.source-note,.small-note{color:var(--muted);font-size:.85rem}.source-note{margin-top:16px}.source-note a,.source-note:link{color:var(--teal)}.formula-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-block:24px}.formula-grid>div{padding:24px 15px;border-radius:12px;background:var(--navy);color:#fff;text-align:center}.formula-grid strong{display:block;font-size:1.8rem;color:var(--aqua);margin-bottom:8px}.formula-grid span{font-size:.9rem}.callout{padding:22px 24px;background:#eaf6f3;border-radius:12px;margin-top:24px}.callout p,.safety p{margin:8px 0 0}.two-column{display:grid;grid-template-columns:1fr 1fr;gap:20px}.lesson-box p:last-child{margin-bottom:0}.lesson-box .tag{margin-bottom:18px}.explorer{border:1px solid #bfd9d7;border-radius:20px;padding:32px;background:#f0f8f6}.explorer-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:32px;align-items:center}.explorer label{display:block;font-weight:700}.explorer input{display:block;width:100%;margin:14px 0 26px;accent-color:var(--teal);min-height:30px}.result{background:var(--navy);border-radius:14px;color:white;padding:22px;text-align:center}.result>span{font-size:.9rem}.result output{display:block;font-size:2.8rem;font-weight:850;color:var(--aqua)}.result p{margin-bottom:0;font-size:.9rem}.explorer .small-note{margin-bottom:0}.circuit{margin:24px 0;background:var(--paper);border-radius:18px;overflow:hidden;border:1px solid var(--line)}.circuit img{display:block;width:100%;height:auto}.circuit figcaption{padding:16px 22px;font-size:.9rem;color:var(--muted);border-top:1px solid var(--line)}.practice li,.steps li,.materials li{margin-bottom:14px;padding-left:7px}.practice,.steps,.materials{padding-left:24px}.steps li::marker{color:var(--teal);font-weight:800}.answer{border:1px solid var(--line);border-radius:10px;margin-top:14px;padding:0 20px}.answer summary{padding:17px 0;cursor:pointer;font-weight:700}.answer p{margin:0 0 20px}.lesson-pagination{display:flex!important;justify-content:space-between;gap:20px;border-top:1px solid var(--line);padding:30px 0 46px;flex-wrap:wrap}.lesson-pagination a{font-size:.95rem;padding:13px 22px}.lesson-list{display:grid;gap:18px}.lesson-card{display:flex;gap:26px;align-items:flex-start;padding:28px;border:1px solid var(--line);border-radius:16px;text-decoration:none;background:var(--paper);transition:border-color .15s,background .15s}.lesson-card:hover{background:#edf7f6;border-color:var(--teal)}.lesson-num{display:grid;place-items:center;width:64px;height:64px;flex-shrink:0;background:#dcefed;border-radius:14px;color:var(--teal);font-weight:850;font-size:1.8rem}.lesson-card h3{font-size:1.5rem;margin-bottom:10px}.lesson-card .eyebrow{display:block;margin-bottom:9px}.lesson-card p{margin-bottom:18px;color:var(--muted)}.lesson-arrow{margin-left:auto;font-size:1.6rem;color:var(--teal)}.pdf-page{border:1px solid var(--line);border-radius:12px;overflow:hidden;margin-top:20px}.pdf-page summary{background:var(--paper);padding:20px;cursor:pointer;font-weight:750}.pdf-page img{width:100%;display:block}.pdf-embed{width:100%;height:75vh;min-height:460px;border:none}.safety{padding:22px 24px;background:#fff1de;border-left:4px solid #b96713;border-radius:0 10px 10px 0;margin-top:28px}.table-scroll{overflow-x:auto;border:1px solid var(--line);border-radius:12px}table{width:100%;border-collapse:collapse;font-size:.95rem}caption{text-align:left;padding:16px;background:var(--paper);font-weight:700}td,th{text-align:left;padding:14px;border-bottom:1px solid var(--line);vertical-align:top}thead{background:var(--navy);color:white}tbody th{font-weight:650}tbody tr:last-child td,tbody tr:last-child th{border-bottom:none}
@media(max-width:760px){.concept-grid,.formula-grid,.two-column,.explorer-grid{grid-template-columns:1fr}.lesson-body{padding-top:26px}.lesson-section{margin-block:34px}.concept,.lesson-box{padding:22px}.formula-grid>div{padding:18px}.explorer{padding:22px}.lesson-card{padding:20px;gap:16px}.lesson-num{width:42px;height:48px;font-size:1.3rem}.lesson-arrow{display:none}.lesson-card h3{font-size:1.3rem}.lesson-pagination{flex-direction:column}.lesson-pagination a{border:1px solid #9aaebe;text-align:center}.objective,.safety{padding:18px}.circuit figcaption{padding:14px;font-size:.875rem}.table-scroll table{min-width:540px}.pdf-page summary{padding:16px}.lesson-top h1{font-size:2.15rem}.answer{padding-inline:16px}}
@media print{.site-header,footer,.lesson-pagination,.skip,.explorer{display:none!important}.wrap{width:100%}.lesson-top{background:white;color:black}.lesson-top .eyebrow,.lesson-top p:last-child{color:black}.back-link{display:none}.lesson-section{break-inside:avoid}.pdf-page{break-before:page}}