/* Leitura longa: ritmo calmo, coluna curta e matemática com espaço. */
.lesson-heading {max-width:1040px;padding-bottom:35px;}
.lesson-heading h1 {font-size:clamp(3.2rem,5vw,4.6rem);line-height:1.1;margin-top:22px;}
.lesson-heading>p {max-width:75ch;}
.lesson-heading .lesson-meta {font-size:.8rem;color:var(--subtle);margin-top:19px;}
.lesson-heading>.text-link {margin-top:12px;}
.lesson-layout {display:grid;grid-template-columns:235px minmax(0,1fr);gap:clamp(28px,4vw,62px);align-items:start;padding-bottom:65px;}
.lesson-sidebar {position:sticky;top:25px;max-height:calc(100vh - 50px);overflow:auto;padding:0 14px 15px 0;scrollbar-width:thin;scrollbar-color:var(--line) transparent;}
.lesson-index {border:1px solid var(--line);border-radius:10px 14px 8px 12px;background:#2b252e66;padding:16px 17px;}
.lesson-index summary {cursor:pointer;font-family:var(--hand);font-size:1.6rem;color:var(--text);line-height:1.25;}
.lesson-index ol {list-style:none;padding:14px 0 0;margin:0;}
.lesson-index li+li {margin-top:9px;}
.lesson-index a {display:block;font-size:.78rem;line-height:1.6;color:var(--muted);padding:4px 0;}
.lesson-index a:hover,.lesson-index a:focus-visible {color:var(--mint);text-decoration:underline;text-underline-offset:4px;}
.lesson-sidebar>.text-link {font-size:1.3rem;display:inline-block;margin-top:15px;}
.lesson-content {max-width:78ch;min-width:0;font-size:1.02rem;line-height:1.95;overflow-wrap:break-word;}
.lesson-content section[id] {scroll-margin-top:28px;}
.lesson-block {padding:0 0 35px;margin:0 0 37px;border-bottom:1px solid #6a596766;}
.lesson-block h2 {font-size:2.6rem;line-height:1.18;margin:0 0 22px;}
.lesson-content h3 {font-family:Inter,system-ui,sans-serif;font-size:1.08rem;line-height:1.6;font-weight:650;margin:30px 0 14px;}
.lesson-content p {color:var(--muted);margin:0 0 20px;}
.lesson-content strong {font-weight:650;color:var(--text);}
.lesson-content ul,.lesson-content ol {padding-left:25px;margin:18px 0 23px;color:var(--muted);}
.lesson-content li {padding-left:4px;margin:0 0 12px;}
.lesson-content a {text-decoration:underline;text-underline-offset:4px;color:var(--mint);}
.lesson-content a.button {text-decoration:none;color:#28252a;}
.lesson-objectives,.lesson-bases,.lesson-recap {padding:24px 27px;background:#b5c2a208;border:1px solid var(--line);border-radius:11px 15px 8px 12px;}
.lesson-objectives h2,.lesson-bases h2,.lesson-recap h2 {font-size:2.25rem;}
.lesson-bases {background:#c6aecf08;}
.lesson-bases ul:last-child,.lesson-objectives ul:last-child {margin-bottom:0;}
.lesson-formula {font-family:Georgia,'Times New Roman',serif;font-size:1.2rem;color:var(--text);text-align:center;line-height:1.8;border-left:2px solid var(--mint);background:#d3a46f08;padding:16px 20px;margin:24px 0;overflow-wrap:anywhere;}
.lesson-content figure {margin:28px 0;}
.lesson-content svg {display:block;width:100%;max-width:100%;height:auto;margin:20px auto;background:var(--canvas);border:1px solid var(--line);border-radius:10px;padding:12px;}
.lesson-content figcaption {font-size:.83rem;color:var(--subtle);line-height:1.7;margin-top:12px;}
.lesson-table {overflow:auto;max-width:100%;margin:24px 0;scrollbar-width:thin;}
.lesson-content table {border-collapse:collapse;width:100%;font-size:.88rem;line-height:1.7;}
.lesson-content td,.lesson-content th {border:1px solid var(--line);padding:10px 14px;text-align:left;color:var(--muted);min-width:90px;}
.lesson-content th {color:var(--text);background:var(--surface);}
.worked-example,.lesson-exercise {border:1px solid #826c7b;background:#2d293255;border-radius:12px 8px 15px 10px;padding:25px 28px;margin:26px 0;}
.lesson-eyebrow {font-size:.73rem!important;color:var(--cyan)!important;text-transform:uppercase;letter-spacing:.08em;line-height:1.6;}
.worked-example h3 {font-family:var(--hand);font-size:2rem;margin:8px 0 20px;line-height:1.2;}
.example-question {color:var(--text);font-weight:500;margin:15px 0 22px;}
.solution-steps>li {padding-left:8px;margin-bottom:18px;}
.solution-steps>li::marker {color:var(--mint);font-weight:600;}
.example-answer {padding:16px 20px;border-left:2px solid var(--cyan);background:#b5c2a20a;margin:24px 0 15px;}
.example-check {padding:13px 0 0;color:var(--subtle);font-size:.91rem;}
.example-answer>strong,.example-check>strong {display:block;margin-bottom:8px;}
.example-answer p:last-child,.example-check p:last-child {margin-bottom:0;}
.lesson-exercise h3 {font-family:var(--hand);font-size:1.9rem;margin:0 0 17px;}
.lesson-hint,.lesson-solution {margin-top:20px;border-top:1px solid var(--line);padding-top:15px;}
.lesson-hint summary,.lesson-solution summary {cursor:pointer;color:var(--mint);padding:4px 0;min-height:44px;line-height:1.7;font-weight:550;}
.lesson-hint>div,.lesson-solution>div {padding-top:12px;}
.lesson-hint {font-size:.93rem;}
.lesson-errors {margin:0;}
.lesson-errors dt {font-weight:650;color:var(--text);margin:26px 0 10px;}
.lesson-errors dd {padding:0 0 0 20px;margin:0;border-left:2px solid var(--violet);color:var(--muted);}
.lesson-sources {font-size:.85rem;line-height:1.85;}
.lesson-sources li {margin:0 0 22px;}
.lesson-sources li p {margin:6px 0 0;}
.lesson-sources .lesson-editorial-note {font-size:.77rem;color:var(--subtle);}
.lesson-pagination {display:grid;grid-template-columns:1fr 1fr;gap:22px;font-size:.9rem;line-height:1.7;}
.lesson-pagination a {border:1px solid var(--line);border-radius:10px;padding:17px;text-decoration:none;}
.lesson-pagination span {display:block;font-size:.72rem;color:var(--subtle);margin-bottom:9px;}
.lesson-library-controls {display:flex;gap:24px;align-items:center;flex-wrap:wrap;}
.lesson-library-controls .search-field {flex:1 1 420px;max-width:750px;}
.lesson-library-controls .filters {flex-wrap:wrap;}
.lesson-grade-label {display:flex;gap:15px;align-items:center;font-size:.85rem;color:var(--muted);}
.lesson-library #lesson-results {margin:22px 0;}
.lesson-library .curriculum-note a {color:var(--mint);text-decoration:underline;}
.lesson-card-grid {display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px;}
.lesson-card {border:1px solid #826c7b;background:var(--surface);border-radius:12px 8px 14px 9px;padding:24px 26px;display:flex;flex-direction:column;}
.lesson-card[hidden] {display:none;}
.lesson-card h2 {font-size:2.2rem;line-height:1.2;margin:14px 0;}
.lesson-card>p:not(.lesson-eyebrow) {font-size:.88rem;line-height:1.85;margin:0 0 20px;}
.lesson-card>.text-link {margin-top:auto;}
.unit-lesson-link {display:flex;width:fit-content;}
@media(max-width:1000px){.lesson-layout {grid-template-columns:195px minmax(0,1fr);gap:28px;}.lesson-content {font-size:1rem;}.worked-example,.lesson-exercise {padding:22px;}}
@media(max-width:760px){.lesson-layout {grid-template-columns:1fr;gap:30px;}.lesson-sidebar {position:static;max-height:none;overflow:visible;padding:0;}.lesson-index ol {columns:2;column-gap:28px;}.lesson-index li {break-inside:avoid;}.lesson-content {max-width:100%;font-size:1rem;line-height:1.95;}.lesson-block h2 {font-size:2.4rem;}.lesson-heading h1 {font-size:3.4rem;}.lesson-card-grid {grid-template-columns:1fr;}}
@media(max-width:480px){.lesson-index ol {columns:1;}.lesson-content {font-size:.97rem;}.lesson-block {padding-bottom:26px;margin-bottom:29px;}.lesson-objectives,.lesson-bases,.lesson-recap {padding:20px;}.worked-example,.lesson-exercise {padding:21px 17px;}.lesson-pagination {grid-template-columns:1fr;}.lesson-formula {padding:14px 12px;font-size:1.12rem;}.lesson-library-controls {gap:17px;}.lesson-library-controls .filters {gap:8px;}.lesson-card {padding:22px;}}