.etb-overview {
  --etb-ink: #17223a;
  --etb-muted: #56647d;
  --etb-line: #dbe3f1;
  --etb-violet: #6756e8;
  --etb-green: #138a72;
  --etb-gold: #a86612;
  --etb-rose: #b33b61;
  color: var(--etb-ink);
  font-size: 16px;
  line-height: 1.55;
  width: 100%;
}

.etb-overview *, .etb-overview *::before, .etb-overview *::after { box-sizing: border-box; }
.etb-overview h2, .etb-overview h3, .etb-overview h4, .etb-overview p { margin: 0; }
.etb-overview a { color: inherit; }
.etb-icon { display: inline-grid; place-items: center; flex: 0 0 auto; width: 22px; height: 22px; }
.etb-icon svg { width: 100%; height: 100%; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.8; }

.etb-lesson-header {
  align-items: flex-start;
  background: #fff;
  border: 1px solid #cfd8ee;
  border-top: 4px solid var(--etb-violet);
  display: flex;
  gap: 32px;
  justify-content: space-between;
  padding: 26px 28px;
}
.etb-title-block { max-width: 850px; }
.etb-eyebrow { align-items: center; color: #5142c8; display: inline-flex; font-size: .79rem; font-weight: 800; gap: 8px; letter-spacing: .08em; text-transform: uppercase; }
.etb-title-block h2 { font-size: 1.75rem; letter-spacing: 0; line-height: 1.2; margin-top: 8px; }
.etb-title-block > p { color: var(--etb-muted); font-size: 1rem; margin-top: 9px; max-width: 72ch; }
.etb-source-line { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-top: 16px; }
.etb-source-line span { align-items: center; color: #435069; display: inline-flex; font-size: .82rem; font-weight: 700; gap: 7px; }
.etb-source-line span::before { background: var(--etb-green); border-radius: 50%; content: ""; height: 7px; width: 7px; }
.etb-header-actions { align-items: flex-end; display: flex; flex-direction: column; gap: 14px; min-width: 300px; }
.etb-page-link { align-items: center; background: #fff; border: 1px solid #bdc8dd; border-radius: 6px; color: #23314b; display: inline-flex; font-size: .86rem; font-weight: 800; gap: 8px; justify-content: center; min-height: 44px; padding: 8px 13px; text-decoration: none; transition: border-color 180ms ease, background 180ms ease, color 180ms ease, box-shadow 180ms ease; }
.etb-page-link:hover { background: #f6f4ff; border-color: #8c7cf4; color: #4d3ed0; }
.etb-page-link:focus-visible, .etb-toc a:focus-visible, .etb-overview summary:focus-visible { outline: 3px solid rgba(103,86,232,.34); outline-offset: 3px; }
.etb-page-link .etb-icon { height: 17px; width: 17px; }
.etb-page-metrics { display: grid; gap: 8px; grid-template-columns: repeat(2, minmax(120px, 1fr)); width: 100%; }
.etb-page-metrics span { background: #f6f7fb; border: 1px solid #e1e6f0; border-radius: 6px; display: flex; flex-direction: column; min-height: 68px; padding: 10px 12px; }
.etb-page-metrics b { font-size: .88rem; }
.etb-page-metrics small { color: #6a758a; font-size: .68rem; font-weight: 700; margin-top: 3px; text-transform: uppercase; }

.etb-reading-layout { align-items: start; display: grid; gap: 20px; grid-template-columns: 210px minmax(0, 1fr) 330px; margin-top: 18px; }
.etb-toc { background: #fff; border: 1px solid var(--etb-line); display: flex; flex-direction: column; padding: 12px; position: sticky; top: 86px; }
.etb-toc-title { color: #7b869a; font-size: .7rem; font-weight: 800; letter-spacing: .12em; padding: 7px 10px 10px; text-transform: uppercase; }
.etb-toc > a { align-items: center; border-left: 3px solid transparent; color: #3f4e68; display: flex; font-size: .9rem; font-weight: 750; gap: 10px; min-height: 44px; padding: 9px 10px; text-decoration: none; transition: background 180ms ease, border-color 180ms ease, color 180ms ease; }
.etb-toc > a:hover { background: #f4f2ff; border-left-color: var(--etb-violet); color: #4c3dcc; }
.etb-toc .etb-icon { height: 19px; width: 19px; }
.etb-pacing-disclosure { border-top: 1px solid var(--etb-line); margin-top: 8px; padding-top: 8px; }
.etb-pacing-disclosure > summary { align-items: center; color: #3f4e68; cursor: pointer; display: flex; font-size: .9rem; font-weight: 750; gap: 10px; list-style: none; min-height: 44px; padding: 9px 10px; }
.etb-pacing-disclosure > summary::-webkit-details-marker { display: none; }
.etb-pacing-disclosure > div { padding: 8px 2px; }
.etb-pacing-disclosure .ch01-pacing-chart { min-width: 670px; transform: scale(.28); transform-origin: top left; width: 670px; }
.etb-pacing-disclosure[open] > div { height: 152px; overflow: hidden; }

.etb-reading-column { background: #fff; border: 1px solid var(--etb-line); min-width: 0; }
.etb-section { padding: 30px 34px; scroll-margin-top: 92px; }
.etb-section + .etb-section { border-top: 1px solid var(--etb-line); }
.etb-section-heading { align-items: flex-start; display: flex; gap: 14px; margin-bottom: 20px; }
.etb-section-heading > div { min-width: 0; }
.etb-section-heading > div > span { color: #66738a; display: block; font-size: .72rem; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }
.etb-section-heading h3 { font-size: 1.35rem; letter-spacing: 0; line-height: 1.25; margin-top: 3px; }
.etb-section-heading p { color: var(--etb-muted); font-size: .9rem; margin-top: 5px; max-width: 70ch; }
.etb-section-icon { background: #eeebff; color: #5645d5; display: grid; height: 44px; place-items: center; width: 44px; }
.etb-section-icon.warm { background: #fff1da; color: #9b5d0c; }
.etb-section-icon.teach { background: #def4ef; color: #087b65; }
.etb-section-icon.example { background: #e8f0ff; color: #3368bd; }
.etb-section-icon.assess { background: #fbe4eb; color: #a62f55; }
.etb-lead { color: #263550; font-size: 1.06rem; font-weight: 620; max-width: 74ch; }
.etb-language-strip { align-items: center; background: #f7f8fc; border-left: 3px solid var(--etb-violet); display: flex; flex-wrap: wrap; gap: 8px; margin-top: 20px; padding: 13px 15px; }
.etb-language-strip strong { color: #4f5c73; font-size: .78rem; margin-right: 4px; text-transform: uppercase; }
.etb-language-strip span { background: #fff; border: 1px solid #dbe2ef; border-radius: 999px; color: #35445f; font-size: .82rem; padding: 5px 10px; }

.etb-launch-grid { display: grid; gap: 16px; grid-template-columns: minmax(220px, .8fr) minmax(0, 1.2fr); }
.etb-launch-card { background: #faf9ff; border-left: 4px solid var(--etb-violet); padding: 18px 20px; }
.etb-launch-card > span, .etb-problem-block > span, .etb-exit-ticket > span, .etb-board-reference > span { color: #6c7487; display: block; font-size: .7rem; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.etb-launch-card h4 { font-size: 1.02rem; line-height: 1.42; margin-top: 6px; }
.etb-launch-card p { color: var(--etb-muted); font-size: .88rem; margin-top: 8px; }
.etb-warmup-wrap { border: 1px solid #dbe7e4; padding: 14px 16px; }
.etb-warmup-wrap .ch01-warmup-grid { margin: 0; }

.etb-sequence-list { list-style: none; margin: 0; padding: 0; }
.etb-sequence-step { display: grid; gap: 14px; grid-template-columns: 38px minmax(0, 1fr); padding-bottom: 24px; position: relative; }
.etb-sequence-step:not(:last-child)::before { background: #d8dfed; content: ""; height: calc(100% - 28px); left: 18px; position: absolute; top: 42px; width: 2px; }
.etb-step-number { background: #fff; border: 2px solid var(--etb-green); border-radius: 50%; color: #0b7562; display: grid; font-size: .82rem; font-weight: 850; height: 38px; place-items: center; position: relative; width: 38px; z-index: 1; }
.etb-step-content { border-bottom: 1px solid #e4e8f0; padding-bottom: 24px; }
.etb-sequence-step:last-child .etb-step-content { border-bottom: 0; padding-bottom: 0; }
.etb-step-heading { align-items: flex-start; display: flex; gap: 16px; justify-content: space-between; }
.etb-phase { color: #0d7d68; font-size: .7rem; font-weight: 850; letter-spacing: .08em; text-transform: uppercase; }
.etb-step-heading h4 { font-size: 1.05rem; margin-top: 3px; }
.etb-step-meta { align-items: center; display: flex; flex: 0 0 auto; flex-wrap: wrap; gap: 6px; justify-content: flex-end; }
.etb-source-badge { border-radius: 999px; display: inline-flex; font-size: .7rem; font-weight: 800; line-height: 1.2; padding: 5px 8px; }
.etb-source-badge.verified { background: #dff7f0; color: #08735f; }
.etb-source-badge.reference { background: #eeeaff; color: #5141c9; }
.etb-source-badge.supplemental { background: #fff0d8; color: #8d550b; }
.etb-teacher-move, .etb-student-evidence { display: grid; gap: 10px; grid-template-columns: 88px minmax(0, 1fr); margin-top: 14px; }
.etb-teacher-move > span, .etb-student-evidence > span { color: #66738a; font-size: .72rem; font-weight: 850; letter-spacing: .07em; padding-top: 2px; text-transform: uppercase; }
.etb-teacher-move p { color: #263550; font-weight: 650; }
.etb-student-evidence p { color: var(--etb-muted); }
.etb-kc-row { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 13px; }
.etb-kc-row button { min-height: 36px; }
.etb-checkpoint { background: #f1faf7; border-left: 3px solid var(--etb-green); margin-top: 15px; padding: 12px 14px; }
.etb-checkpoint-head { align-items: center; color: #0b715e; display: flex; font-size: .8rem; gap: 7px; }
.etb-checkpoint-head .etb-icon { height: 18px; width: 18px; }
.etb-checkpoint p { color: #293751; font-size: .9rem; margin-top: 6px; }
.etb-look-for { display: flex; font-size: .82rem; gap: 8px; margin-top: 8px; }
.etb-look-for b { color: #0b715e; flex: 0 0 auto; }
.etb-look-for span { color: #4d5b72; }

.etb-example-list { border-top: 1px solid var(--etb-line); }
.etb-example { border-bottom: 1px solid var(--etb-line); }
.etb-example > summary { align-items: center; cursor: pointer; display: grid; gap: 12px; grid-template-columns: 34px minmax(0, 1fr) auto 18px; list-style: none; min-height: 76px; padding: 12px 4px; }
.etb-example > summary::-webkit-details-marker, .etb-margin-panel > summary::-webkit-details-marker { display: none; }
.etb-example > summary:hover { background: #fafbfe; }
.etb-example-index { background: #eeebff; color: #5645d5; display: grid; font-size: .8rem; font-weight: 850; height: 32px; place-items: center; width: 32px; }
.etb-example-summary-copy { display: flex; flex-direction: column; min-width: 0; }
.etb-example-label { color: #66738a; font-size: .72rem; font-weight: 750; }
.etb-example-summary-copy strong { font-size: .92rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.etb-example-summary-meta { align-items: center; display: flex; font-size: .75rem; gap: 7px; }
.etb-disclosure-icon { border-bottom: 2px solid currentColor; border-right: 2px solid currentColor; display: inline-block; height: 8px; transform: rotate(45deg); transition: transform 180ms ease; width: 8px; }
.etb-example[open] .etb-disclosure-icon, .etb-margin-panel[open] .etb-disclosure-icon { transform: rotate(225deg); }
.etb-example-body { background: #fafbfe; border-left: 3px solid #8a7af2; padding: 20px 22px; }
.etb-problem-block p { color: #18243a; font-size: 1.02rem; font-weight: 700; margin-top: 5px; }
.etb-worked-steps { list-style: none; margin: 18px 0 0; padding: 0; }
.etb-worked-steps li { align-items: start; display: grid; gap: 10px; grid-template-columns: 26px minmax(0, 1fr); padding: 8px 0; }
.etb-worked-steps li > span { background: #e9edf6; border-radius: 50%; display: grid; font-size: .72rem; font-weight: 850; height: 24px; place-items: center; width: 24px; }
.etb-worked-steps li div { display: flex; flex-direction: column; gap: 5px; }
.etb-worked-steps code { background: #fff; border: 1px solid #dce3ef; color: #24334d; font-size: .9rem; padding: 8px 10px; white-space: pre-wrap; }
.etb-answer { align-items: baseline; background: #ebf8f4; border: 1px solid #c9eade; display: flex; gap: 10px; margin-top: 14px; padding: 10px 12px; }
.etb-answer > span { color: #0b725f; font-size: .72rem; font-weight: 850; text-transform: uppercase; }
.etb-example-actions { align-items: center; display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; margin-top: 16px; }
.etb-example-actions .etb-kc-row { margin-top: 0; }

.etb-assess-grid { display: grid; gap: 16px; grid-template-columns: minmax(0, 1.1fr) minmax(260px, .9fr); }
.etb-exit-ticket { border-left: 4px solid var(--etb-rose); padding: 18px 20px; }
.etb-exit-ticket h4, .etb-board-reference h4 { font-size: 1rem; margin-top: 5px; }
.etb-exit-ticket > p { color: #35435c; margin-top: 7px; }
.etb-exit-ticket details { margin-top: 12px; }
.etb-exit-ticket summary { color: #563fd0; cursor: pointer; font-size: .82rem; font-weight: 800; min-height: 44px; padding: 10px 0; }
.etb-board-reference { border: 1px solid #dce3ef; padding: 17px 18px; }
.etb-board-reference .ch01-board-model { margin-top: 10px; }

.etb-margin-column { display: flex; flex-direction: column; gap: 12px; position: sticky; top: 86px; }
.etb-margin-panel, .etb-source-note { background: #fff; border: 1px solid var(--etb-line); }
.etb-margin-panel > summary { align-items: center; cursor: pointer; display: flex; font-size: .9rem; font-weight: 850; gap: 9px; justify-content: flex-start; list-style: none; min-height: 52px; padding: 10px 14px; }
.etb-margin-panel > summary .etb-disclosure-icon { margin-left: auto; }
.etb-margin-panel > div { border-top: 1px solid var(--etb-line); padding: 14px; }
.etb-support-grid { display: grid; gap: 18px; }
.etb-support-grid h4 { align-items: center; color: #31405b; display: flex; font-size: .86rem; gap: 7px; }
.etb-support-grid h4 .etb-icon { height: 18px; width: 18px; }
.etb-support-item { border-left: 2px solid #d5ddeb; margin-top: 10px; padding-left: 10px; }
.etb-support-item strong { display: block; font-size: .8rem; }
.etb-support-item p, .etb-support-grid li { color: #59677f; font-size: .78rem; line-height: 1.5; margin-top: 3px; }
.etb-support-grid ul { margin: 9px 0 0; padding-left: 18px; }
.etb-standard-list { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 14px; }
.etb-standard-list button { min-height: 36px; }
.etb-margin-panel .ch01-kc-matrix { font-size: .68rem; grid-template-columns: minmax(110px, 1.5fr) repeat(4, 28px); overflow: hidden; }
.etb-source-note { border-top: 3px solid var(--etb-green); padding: 15px; }
.etb-source-note strong { font-size: .86rem; }
.etb-source-note p { color: #58667e; font-size: .78rem; margin: 6px 0 12px; }
.etb-source-note .etb-page-link { width: 100%; }
.etb-empty { color: #6b778c; font-size: .9rem; }

html[data-theme="night"] .etb-overview { --etb-ink: #edf2ff; --etb-muted: #b7c1d6; --etb-line: #3a4660; }
html[data-theme="night"] .etb-lesson-header,
html[data-theme="night"] .etb-toc,
html[data-theme="night"] .etb-reading-column,
html[data-theme="night"] .etb-margin-panel,
html[data-theme="night"] .etb-source-note { background: #1b2539; }
html[data-theme="night"] .etb-title-block > p,
html[data-theme="night"] .etb-section-heading p,
html[data-theme="night"] .etb-support-item p,
html[data-theme="night"] .etb-support-grid li,
html[data-theme="night"] .etb-source-note p,
html[data-theme="night"] .etb-student-evidence p { color: #b7c1d6; }
html[data-theme="night"] .etb-source-line span,
html[data-theme="night"] .etb-toc > a,
html[data-theme="night"] .etb-pacing-disclosure > summary { color: #cbd4e7; }
html[data-theme="night"] .etb-page-metrics span,
html[data-theme="night"] .etb-launch-card,
html[data-theme="night"] .etb-language-strip,
html[data-theme="night"] .etb-example-body,
html[data-theme="night"] .etb-checkpoint { background: #222f46; }
html[data-theme="night"] .etb-page-link,
html[data-theme="night"] .etb-language-strip span,
html[data-theme="night"] .etb-worked-steps code { background: #172034; border-color: #44516b; color: #edf2ff; }
html[data-theme="night"] .etb-teacher-move p,
html[data-theme="night"] .etb-problem-block p,
html[data-theme="night"] .etb-checkpoint p { color: #edf2ff; }
html[data-theme="night"] .etb-answer { background: #173d37; border-color: #296c60; }

@media (max-width: 1500px) {
  .etb-reading-layout { grid-template-columns: 190px minmax(0, 1fr); }
  .etb-margin-column { display: grid; grid-column: 1 / -1; grid-template-columns: repeat(3, minmax(0, 1fr)); position: static; }
}

@media (max-width: 1024px) {
  .etb-lesson-header { flex-direction: column; }
  .etb-header-actions { align-items: stretch; min-width: 0; width: 100%; }
  .etb-reading-layout { grid-template-columns: 1fr; }
  .etb-toc { display: grid; gap: 4px; grid-template-columns: repeat(3, minmax(0, 1fr)); overflow: visible; position: static; }
  .etb-toc-title { grid-column: 1 / -1; }
  .etb-pacing-disclosure { grid-column: 1 / -1; }
  .etb-margin-column { grid-column: auto; grid-template-columns: 1fr; }
}

@media (max-width: 680px) {
  .etb-overview { font-size: 16px; }
  .etb-lesson-header { gap: 20px; padding: 20px 16px; }
  .etb-title-block h2 { font-size: 1.45rem; }
  .etb-page-metrics { grid-template-columns: 1fr; }
  .etb-toc { grid-template-columns: 1fr 1fr; padding: 8px; }
  .etb-toc > a { font-size: .82rem; }
  .etb-section { padding: 24px 16px; }
  .etb-section-heading h3 { font-size: 1.2rem; }
  .etb-launch-grid, .etb-assess-grid { grid-template-columns: 1fr; }
  .etb-step-heading { flex-direction: column; }
  .etb-step-meta { justify-content: flex-start; }
  .etb-teacher-move, .etb-student-evidence { grid-template-columns: 1fr; gap: 2px; }
  .etb-example > summary { grid-template-columns: 34px minmax(0, 1fr) 18px; }
  .etb-example-summary-meta { align-items: flex-start; grid-column: 2 / -1; justify-content: flex-start; }
  .etb-example-summary-copy strong { white-space: normal; }
  .etb-example-body { padding: 17px 14px; }
  .etb-example-actions { align-items: stretch; flex-direction: column; }
  .etb-example-actions .etb-page-link { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  .etb-overview *, .etb-overview *::before, .etb-overview *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; }
}