/* Accessible, locally rendered learning experience. */
.lesson-shell { max-width: 1120px; }
.lesson-hero { padding: 34px 0 48px; max-width: 860px; }
.lesson-hero h1 { font: 600 clamp(42px,5.4vw,68px)/1.1 var(--heading); letter-spacing: -2.8px; margin: 20px 0 24px; }
.lesson-deck { max-width: 710px; color: var(--muted); font-size: 19px; line-height: 1.7; }
.lesson-byline { display: flex; flex-wrap: wrap; align-items: baseline; gap: 5px; font-size: 13px; margin-top: 24px; }
.lesson-byline a { text-decoration: underline; text-underline-offset: 4px; font-weight: 600; }
.lesson-byline span { flex-basis: 100%; color: var(--muted); font-size: 12px; }
.lesson-tags { display: flex; flex-wrap: wrap; gap: 8px 22px; margin-top: 20px; color: var(--muted); font-size: 11px; }
.lesson-hero-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 18px 26px; margin-top: 28px; }
.lesson-hero-actions .text-link { font-size: 12px; }
.lesson-intro-grid { display: grid; grid-template-columns: 1.2fr 1fr; border: 1px solid var(--line); border-radius: 8px; overflow: hidden; }
.lesson-definition,.lesson-outcomes { padding: 28px 32px; }
.lesson-outcomes { background: var(--blue-soft); }
.lesson-intro-grid h2 { font: 600 21px/1.4 var(--heading); letter-spacing: -.5px; margin: 0 0 14px; }
.lesson-intro-grid p,.lesson-intro-grid li { font-size: 14px; color: var(--muted); }
.lesson-intro-grid p:last-child { margin-bottom: 0; }
.lesson-intro-grid ul { padding-left: 20px; margin: 0; }
.lesson-intro-grid li+li { margin-top: 10px; }
.lesson-sample-note { margin: 20px 0 30px; font-size: 12px; color: var(--muted); max-width: 900px; }
.lesson-nav { display: flex; flex-wrap: wrap; gap: 12px 26px; border-block: 1px solid var(--line); padding: 19px 0; font-size: 12px; font-weight: 600; }
.lesson-nav a:hover { color: var(--blue-deep); text-decoration: underline; }
.lesson-section { padding: 54px 0; border-bottom: 1px solid var(--line); scroll-margin-top: 24px; }
.lesson-section-heading { max-width: 780px; margin-bottom: 26px; }
.lesson-section h2,.lesson-takeaway h2,.lesson-faq h2 { font: 600 clamp(27px,3vw,36px)/1.25 var(--heading); letter-spacing: -1px; margin: 13px 0 16px; }
.lesson-section-heading>p { font-size: 15px; color: var(--muted); }
.lesson-section h3 { font: 600 19px/1.45 var(--heading); letter-spacing: -.4px; margin: 0 0 12px; }
.lesson-exercise { padding: 28px; border: 1px solid #cbd7ef; border-radius: 8px; background: #f7f9ff; margin-top: 24px; }
.lesson-exercise fieldset { padding: 0; border: 0; margin: 0 0 22px; min-width: 0; }
.lesson-exercise legend { padding: 0; font-weight: 600; font-size: 16px; }
.lesson-exercise fieldset>p { font-size: 13px; color: var(--muted); margin: 8px 0 20px; }
.lesson-sequence { display: grid; grid-template-columns: repeat(4,minmax(0,1fr)); gap: 18px; }
.lesson-sequence label>span { display: block; font-size: 12px; font-weight: 600; margin-bottom: 8px; }
.lesson-sequence>label { display: block; min-width: 0; }
.lesson-sequence select {
 display: block;
 -webkit-appearance: none;
 appearance: none;
 font: inherit;
 font-size: 16px;
 line-height: 1.5;
 width: 100%;
 min-width: 0;
 min-height: 52px;
 margin: 0;
 padding: 12px 48px 12px 14px;
 background-color: white;
 background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='m4 6 4 4 4-4' fill='none' stroke='%23334155' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
 background-repeat: no-repeat;
 background-position: right 16px center;
 background-size: 16px 16px;
 border: 1px solid #8794ab;
 border-radius: 5px;
 color: var(--ink);
 cursor: pointer;
}
.lesson-choice { display: flex; align-items: start; gap: 13px; cursor: pointer; background: white; border: 1px solid var(--line); border-radius: 5px; padding: 15px; margin-top: 10px; font-size: 14px; line-height: 1.65; }
.lesson-choice:hover { border-color: #6c85b8; }
.lesson-choice:has(input:checked) { border-color: var(--blue); background: #f0f5ff; }
.lesson-choice input { flex: 0 0 auto; width: 18px; height: 18px; margin: 3px 0 0; accent-color: var(--blue-deep); }
.lesson-feedback { font-size: 14px; color: var(--ink); margin: 15px 0 0; max-width: 800px; }
.lesson-feedback:empty { display: none; }
.lesson-feedback[data-result="success"] { border-left: 3px solid var(--blue-deep); padding-left: 12px; }
.lesson-feedback[data-result="retry"] { border-left: 3px solid #8e4c13; padding-left: 12px; }
.lesson-explainer { border: 1px solid var(--line); border-radius: 6px; padding: 18px 22px; margin-top: 22px; }
.lesson-explainer summary,.lesson-prompt-panel summary { font-size: 14px; font-weight: 600; cursor: pointer; }
.lesson-explainer p { font-size: 14px; color: var(--muted); }
.lesson-explainer h3 { margin-top: 20px; }
.lesson-source-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.lesson-source { border: 1px solid var(--line); border-radius: 8px; padding: 25px; background: #fafbfc; }
.lesson-source .eyebrow { font-size: 9px; margin-bottom: 12px; }
.lesson-source-update { background: #f1f6ff; border-color: #d2dff6; }
.lesson-source p,.lesson-source li { font-size: 14px; }
.lesson-source ul { padding-left: 20px; margin-bottom: 0; }
.lesson-source li+li { margin-top: 8px; }
.lesson-note { border-left: 3px solid var(--blue); padding: 4px 0 4px 22px; margin-top: 28px; }
.lesson-note p,.lesson-note li,.lesson-tools,.lesson-seo p { font-size: 14px; color: var(--muted); }
.lesson-note a,.lesson-explainer a,.lesson-seo a { text-decoration: underline; text-underline-offset: 3px; color: var(--blue-deep); }
.lesson-note ul { padding-left: 20px; }
.lesson-tools { margin-bottom: 22px; }
.lesson-prompt-panel { border: 1px solid var(--line); border-radius: 8px; padding: 24px; background: #f8fafc; }
.lesson-prompt-panel pre { font: 13px/1.85 var(--font); white-space: pre-wrap; overflow-wrap: anywhere; margin: 22px 0; max-width: 850px; }
.lesson-draft { background: #fffaf2; border: 1px solid #e7d8c0; padding: 28px; border-radius: 8px; }
.lesson-draft .eyebrow { color: #774c18; font-size: 10px; margin-bottom: 15px; }
.lesson-draft p { font-size: 16px; line-height: 1.9; margin-bottom: 0; max-width: 850px; }
.lesson-editor-note { padding: 28px 0 0; max-width: 760px; }
.lesson-editor-note>p { font: 600 23px/1.5 var(--heading); letter-spacing: -.6px; margin: 14px 0 6px; }
.lesson-editor-note>span:last-child { color: var(--muted); font-size: 12px; }
.lesson-seo { max-width: 850px; }
.lesson-progress { font-size: 13px; font-weight: 600; margin: 0 0 20px; color: var(--blue-deep); }
.lesson-small { font-size: 12px; color: var(--muted); margin-bottom: 0; }
.lesson-result { background: var(--blue-soft); padding: 28px; border: 1px solid #cbd7ef; border-radius: 8px; margin-top: 24px; }
.lesson-result .eyebrow { margin-bottom: 14px; }
.lesson-result p { font-size: 14px; margin-bottom: 0; }
.lesson-metadata { font-size: 14px; }
.lesson-metadata dt { font-weight: 600; margin-top: 15px; }
.lesson-metadata dd { margin: 5px 0 0; color: var(--muted); }
.lesson-takeaway { display: grid; grid-template-columns: 1.2fr 1fr; gap: 40px; align-items: center; padding: 40px; margin: 48px 0; border: 1px solid var(--line); border-radius: 8px; }
.lesson-takeaway p { color: var(--muted); font-size: 14px; }
.lesson-takeaway .button { font-size: 12px; margin-top: 12px; }
.lesson-takeaway-rule { border-left: 1px solid var(--line); padding-left: 32px; }
.lesson-takeaway-rule>span { font-size: 13px; font-weight: 600; color: var(--blue-deep); }
.lesson-takeaway-rule .text-link { font-size: 12px; cursor: pointer; background: none; border-width: 0 0 1px; }
.lesson-faq details { padding: 18px 0; border-bottom: 1px solid var(--line); }
.lesson-faq summary { cursor: pointer; font-size: 15px; font-weight: 500; }
.lesson-faq p { font-size: 14px; color: var(--muted); max-width: 820px; }
.lesson-author { padding: 40px 0 25px; max-width: 800px; }
.lesson-author h2 { font: 600 25px/1.4 var(--heading); margin: 12px 0; }
.lesson-author p { font-size: 14px; color: var(--muted); }
.lesson-author .text-link { font-size: 12px; margin: 12px 22px 0 0; }
.lesson-shell [hidden] { display: none !important; }
.lesson-shell :is(select,input,button,summary,a):focus-visible { outline: 3px solid var(--blue-deep); outline-offset: 4px; }
@media(max-width:900px) {
 .lesson-sequence { grid-template-columns: repeat(2,minmax(0,1fr)); gap: 16px; }
}
@media(max-width:700px) {
 .lesson-hero { padding-top: 24px; }
 .lesson-hero h1 { font-size: 43px; letter-spacing: -1.8px; }
 .lesson-deck { font-size: 16px; }
 .lesson-intro-grid,.lesson-source-grid,.lesson-takeaway { grid-template-columns: 1fr; }
 .lesson-definition,.lesson-outcomes { padding: 23px; }
 .lesson-section { padding-block: 38px; }
 .lesson-exercise,.lesson-prompt-panel,.lesson-draft { padding: 20px; }
 .lesson-choice { font-size: 13px; padding: 13px; }
 .lesson-takeaway { padding: 25px; gap: 22px; }
 .lesson-takeaway-rule { padding: 22px 0 0; border-left: 0; border-top: 1px solid var(--line); }
 .lesson-nav { gap: 12px 19px; }
 .lesson-nav a:first-child { flex-basis: 100%; }
 .lesson-hero-actions .button { width: 100%; justify-content: center; }
 .lesson-section .button { font-size: 12px; padding-inline: 16px; }
}
@media(max-width:500px) {
 .lesson-sequence { grid-template-columns: minmax(0,1fr); }
}
@media(forced-colors:active) {
 .lesson-sequence select { -webkit-appearance: auto; appearance: auto; background-image: none; padding-right: 14px; }
}
@media(prefers-reduced-motion:reduce) { html { scroll-behavior: auto; } }