:root {
  color-scheme: light;
  --paper: #faf8f2;
  --ink: #253e37;
  --muted: #617069;
  --line: #d9ddd2;
  --accent: #a1462e;
  --mono: ui-monospace, SFMono-Regular, Consolas, monospace;
  --serif: 'Iowan Old Style', 'Palatino Linotype', 'Book Antiqua', Georgia, serif;
}
* { box-sizing: border-box; }
html { scroll-padding-top: 2rem; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 16px/1.65 system-ui, sans-serif; }
a { color: inherit; text-underline-offset: .2em; }
a:hover { color: var(--accent); }
a:focus-visible, summary:focus-visible, pre:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible { outline: 3px solid var(--accent); outline-offset: 5px; }
button, input { font: inherit; }
button { cursor: pointer; }
button:disabled { cursor: default; }
.visually-hidden { position: absolute; width: 1px; height: 1px; padding: 0; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
img { max-width: 100%; height: auto; }
h1, h2, h3, p { margin-top: 0; }
.site-header, .home, .site-footer { width: min(1320px, calc(100% - 112px)); margin-inline: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; min-height: 100px; border-bottom: 1px solid var(--line); gap: 30px; }
.brand { display: inline-flex; align-items: center; gap: 12px; font: bold 25px var(--serif); text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 30px; height: 32px; color: var(--paper); background: var(--ink); border-radius: 3px; font: 23px var(--serif); }
.site-header nav { display: flex; gap: 32px; font-size: 14px; }
.site-header nav a { text-decoration: none; }
.skip-link { position: absolute; left: 1rem; top: -100px; background: white; padding: 10px; z-index: 5; }
.skip-link:focus { top: 1rem; }
.eyebrow { font: 11px/1.6 var(--mono); letter-spacing: .12em; text-transform: uppercase; color: var(--accent); margin-bottom: 22px; }
.hero { display: grid; grid-template-columns: 1.15fr 1fr; gap: 65px; align-items: center; padding-block: 78px 85px; }
.hero h1 { font: 500 clamp(40px, 4.9vw, 70px)/1.06 var(--serif); letter-spacing: -.04em; margin-bottom: 28px; }
em { font-weight: inherit; }
.hero-intro { font-size: 17px; line-height: 1.8; max-width: 490px; color: #56675e; margin-bottom: 28px; }
.button { background: var(--ink); color: var(--paper); padding: 12px 19px; display: inline-flex; gap: 32px; align-items: center; text-decoration: none; font-size: 14px; }
.button:hover { background: #34594d; color: white; }
.hero-note { font: 11px/1.7 var(--mono); color: var(--muted); margin: 20px 0 0; }
.hero-plate {
  border: 1px solid #c6cec0;
  background: #f0eee5;
  transform: rotate(-3deg);
  box-shadow: 0 12px 30px rgb(37 62 55 / 14%);
  transition: transform .25s ease, box-shadow .25s ease;
}
@media (hover: hover) and (pointer: fine) and (prefers-reduced-motion: no-preference) {
  .hero-plate:hover { transform: translateY(-4px) rotate(-4deg); box-shadow: 0 20px 42px rgb(37 62 55 / 20%); }
}
.plate-heading { display: flex; justify-content: space-between; padding: 15px 20px; border-bottom: 1px solid #c6cec0; font: 11px/1.5 var(--mono); text-transform: uppercase; letter-spacing: .05em; }
.hero-plate img { display: block; width: 100%; }
.hero-plate p { margin: 0; padding: 13px 17px; font: 10px/1.6 var(--mono); border-top: 1px solid #c6cec0; color: #58685c; }
.status-dot { display: inline-block; width: 6px; height: 6px; border-radius: 100%; background: #4d7654; margin-right: 7px; }
.processor-section { border-top: 1px solid var(--line); padding-block: 55px 70px; }
.section-heading { display: flex; justify-content: space-between; align-items: end; gap: 32px; margin-bottom: 35px; }
.section-heading .eyebrow { margin-bottom: 12px; }
.section-heading h2, .about-section h2 { font: 500 42px/1.1 var(--serif); letter-spacing: -.03em; margin: 0; }
.section-heading > p { font-size: 14px; color: var(--muted); margin-bottom: 0; }
.processor-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.processor-card { text-decoration: none; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); padding: 25px 24px 18px; transition: background .15s; }
.processor-card:hover { background: #efeee4; color: var(--ink); }
.card-top { display: flex; justify-content: space-between; font: 12px var(--mono); margin-bottom: 25px; }
.card-year { color: var(--accent); }
.card-number { color: #7b8375; }
.processor-card h3 { font: 500 clamp(19px, 1.9vw, 27px)/1.25 var(--serif); margin-bottom: 9px; }
.processor-card > p { font: 11px/1.6 var(--mono); color: var(--muted); }
.card-bottom { display: flex; justify-content: space-between; align-items: center; font-size: 12px; padding-top: 30px; }
.card-bottom > :last-child { font-size: 21px; color: var(--accent); }
.about-section { border-top: 1px solid var(--line); display: grid; grid-template-columns: 1fr 1.2fr; gap: 90px; padding: 65px 0 90px; }
.about-section h2 { font-size: 54px; line-height: 1.15; }
.about-section h2 em { color: var(--accent); }
.about-copy { padding-top: 6px; max-width: 610px; }
.about-copy p { color: #53665b; }
.about-copy .lead { font: 24px/1.45 var(--serif); color: var(--ink); }
.text-link { display: block; font-size: 14px; margin-top: 16px; }
.site-footer { display: flex; flex-wrap: wrap; align-items: center; gap: 20px; border-top: 1px solid var(--line); padding-block: 30px; font-size: 11px; color: var(--muted); }
.site-footer p { margin: 0; }
.site-footer p:last-child { margin-left: auto; }
.wordmark { font: bold 19px var(--serif); color: var(--ink); text-decoration: none; }
.chapter-layout { width: min(1300px, calc(100% - 112px)); margin: 45px auto 90px; display: grid; grid-template-columns: 230px minmax(0, 860px); gap: 60px; justify-content: center; align-items: start; }
.chapter-sidebar { position: sticky; top: 26px; max-height: calc(100vh - 52px); overflow: auto; padding: 0 15px 15px 0; scrollbar-width: thin; }
.back-link { font: 12px var(--mono); text-decoration: none; display: block; margin-bottom: 30px; color: var(--accent); }
.contents summary { font: 11px/1.6 var(--mono); text-transform: uppercase; letter-spacing: .09em; cursor: pointer; }
.contents ol { list-style: none; padding: 0; margin-top: 20px; }
.contents li { line-height: 1.45; margin-bottom: 11px; }
.contents a { font-size: 12px; text-decoration: none; color: #596a60; display: block; border-left: 2px solid var(--line); padding-left: 12px; }
.contents a:hover { border-color: var(--accent); color: var(--accent); }
.chapter-main { min-width: 0; }
.chapter-header { padding-bottom: 25px; border-bottom: 1px solid var(--line); }
.chapter-header .eyebrow { margin-bottom: 14px; }
.chapter-header .eyebrow span { padding-inline: 10px; color: #8b968a; }
.chapter-header h1 { font: 500 60px/1.12 var(--serif); letter-spacing: -.035em; margin-bottom: 25px; }
.chapter-meta { font: 11px/1.6 var(--mono); color: var(--muted); display: flex; gap: 20px; justify-content: space-between; }
.state-map { margin: 22px 0 30px; background: #f0eee5; border: 1px solid var(--line); }
.state-map > summary { cursor: pointer; padding: 13px 17px; font-size: 13px; }
.state-map figure { margin: 0 16px 16px; }
.state-map img { display: block; margin: auto; }
figcaption { font: 12px/1.7 system-ui, sans-serif; color: var(--muted); margin-top: 12px; }
.chapter-prose { font-size: 16px; line-height: 1.85; overflow-wrap: break-word; }
.chapter-prose p { margin-bottom: 1.3em; }
.chapter-prose h2 { border-top: 1px solid var(--line); padding-top: 36px; margin: 52px 0 24px; font: 500 35px/1.2 var(--serif); letter-spacing: -.02em; }
.chapter-prose h3 { font: 500 26px/1.3 var(--serif); margin: 35px 0 20px; }
.chapter-prose h4 { margin-bottom: 15px; }
.chapter-prose a { color: #875037; }
.chapter-prose :not(pre) > code { font: .82em/1.7 var(--mono); background: #edece4; border-radius: 3px; padding: 2px 4px; }
:is(.chapter-prose, .lesson-prose) table { display: block; width: 100%; border-collapse: collapse; overflow-x: auto; font-size: 13px; margin-block: 24px; }
:is(.chapter-prose, .lesson-prose) th, :is(.chapter-prose, .lesson-prose) td { border-bottom: 1px solid var(--line); padding: 10px 13px; text-align: left; vertical-align: top; }
:is(.chapter-prose, .lesson-prose) th { background: #efeee5; font-weight: 600; }
.code-block { background: #efefe7 !important; border: 1px solid #dcded3; margin-block: 24px; }
.code-block pre { margin: 0; padding: 20px 22px; overflow-x: auto; font: 12px/1.8 var(--mono); tab-size: 2; }
.code-block code { font: inherit; }
.code-block .k { color: #8a3f35; }
.code-block .s { color: #3d663e; }
.code-block .m, .code-block .no { color: #276776; }
.code-block .c, .code-block .c1, .code-block .cm { color: #687467; }
.code-block .nt { color: #246174; }
.code-block .na { color: #72551f; }
.architecture-diagram { margin: 30px 0; padding: 20px; border: 1px solid var(--line); background: #fffefa; }
.architecture-diagram img { display: block; width: 100%; }
.architecture-diagram summary { cursor: pointer; font: 12px/1.7 var(--mono); margin-top: 12px; }
.architecture-diagram .code-block { margin-bottom: 0; }
.chapter-pagination { display: flex; justify-content: space-between; gap: 30px; border-top: 1px solid var(--line); padding-top: 30px; margin-top: 60px; }
.chapter-pagination a { text-decoration: none; }
.chapter-pagination span { display: block; font: 11px var(--mono); color: var(--muted); margin-bottom: 8px; }
.chapter-pagination strong { font: 24px var(--serif); }
.learn-section { border-top: 1px solid var(--line); display: grid; grid-template-columns: 1fr 1fr; gap: 60px; padding-block: 40px; }
.learn-section .eyebrow { margin-bottom: 12px; }
.learn-section h2 { font: 500 34px/1.15 var(--serif); letter-spacing: -.02em; margin: 0; }
.learn-section p:not(.eyebrow) { color: var(--muted); margin-bottom: 0; max-width: 500px; }
.lesson { width: min(860px, calc(100% - 112px)); margin: 55px auto 90px; }
.lesson-header { max-width: 650px; margin-bottom: 35px; }
.lesson-header .eyebrow { margin-bottom: 16px; }
.lesson h1 { font: 500 clamp(42px, 5vw, 62px)/1.08 var(--serif); letter-spacing: -.035em; margin-bottom: 22px; }
.lesson h1 em { color: var(--accent); }
.lesson-intro { font-size: 18px; line-height: 1.7; color: #53665b; }
.byte-explorer { border: 1px solid #c6cec0; background: #f0eee5; padding: 24px 30px; }
.instrument-heading { display: flex; justify-content: space-between; gap: 12px; font: 11px/1.6 var(--mono); text-transform: uppercase; letter-spacing: .05em; padding-bottom: 16px; margin-bottom: 18px; border-bottom: 1px solid #c6cec0; }
.byte-explorer > p { font-size: 14px; color: #53665b; margin-bottom: 22px; }
.byte-explorer fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
.byte-bits { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.nibble-bits { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; }
.byte-bit { text-align: center; }
.bit-weight { display: block; font: 12px/1.6 var(--mono); color: #53665b; margin-bottom: 8px; }
.byte-bit button { display: block; width: 100%; min-height: 58px; border: 1px solid #9ba99c; border-radius: 3px; font: 32px/1 var(--mono); background: var(--paper); color: #53665b; }
.byte-bit button[aria-pressed="true"] { background: var(--ink); border-color: var(--ink); color: var(--paper); }
.byte-bit button:enabled:hover { border-color: var(--accent); box-shadow: inset 0 0 0 1px var(--accent); }
.nibble-label { margin: 10px 0 0; padding-top: 9px; border-top: 1px solid #b6c1b2; text-align: center; font: 11px/1.5 var(--mono); color: #53665b; }
.nibble-label strong { font-size: 18px; margin-left: 8px; color: var(--accent); }
.byte-sum-label { font-size: 12px; color: #53665b; margin: 22px 0 5px; }
.byte-sum { font: 18px/1.6 var(--mono); margin-bottom: 24px; overflow-wrap: anywhere; }
.byte-representations { display: grid; grid-template-columns: 1.2fr 1fr 1fr; gap: 18px; }
.byte-representations label { font-size: 14px; font-weight: 600; }
.byte-representations label > span { display: block; font-size: 11px; font-weight: 400; color: #53665b; margin: 3px 0 8px; }
.byte-representations input { width: 100%; min-width: 0; border: 1px solid #9ba99c; border-radius: 3px; background: var(--paper); color: var(--ink); font: 20px/1.4 var(--mono); padding: 10px; }
.byte-representations input[aria-invalid="true"] { border: 2px solid var(--accent); padding: 9px; }
.byte-error { color: var(--accent); font-size: 13px; margin: 12px 0; }
.byte-error:empty { display: none; }
.clear-byte { border: 1px solid #9ba99c; border-radius: 3px; background: transparent; color: var(--ink); font-size: 12px; padding: 10px 14px; margin-top: 18px; }
.clear-byte:enabled:hover { background: var(--paper); }
.lesson-prose { max-width: 650px; margin-inline: auto; }
.lesson-prose h2 { font: 500 32px/1.2 var(--serif); letter-spacing: -.02em; margin: 45px 0 22px; }
.lesson-prose code { font: .88em var(--mono); background: #edece4; padding: 2px 4px; }
.lesson-prompt { border-left: 3px solid var(--accent); background: #f0eee5; padding: 18px 22px; margin: 25px 0; font-size: 14px; }
.lesson-prompt p { margin: 0; }
.lesson-prompt summary { cursor: pointer; color: #875037; margin-top: 12px; }
.lesson-prompt details p { margin-top: 12px; }
.lesson-prompt > a { display: inline-block; margin-top: 12px; font-size: 12px; color: #875037; }
.byte-addition { border: 1px solid #c6cec0; border-bottom: 0; background: #fffefa; padding: 24px 30px; }
.addition-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; border: 0; margin: 0 0 24px; padding: 0; min-width: 0; }
.addition-actions .button { border: 1px solid var(--ink); border-radius: 3px; }
.addition-actions .clear-byte { margin: 0; }
.addition-actions button:disabled { opacity: .55; }
.addition-label { font: 11px/1.6 var(--mono); text-transform: uppercase; letter-spacing: .05em; color: var(--muted); margin-bottom: 8px; }
.addition-equation { font: 26px/1.5 var(--mono); margin-bottom: 18px; }
.addition-bits { display: flex; gap: 24px; align-items: start; }
.carry-result, .stored-result { display: flex; flex-direction: column; align-items: center; gap: 8px; font: 12px/1.6 var(--mono); }
.carry-result { padding-right: 24px; border-right: 1px dashed #9ba99c; }
.carry-result .bit-weight { margin: 0; }
.carry-digit, .flag-digit { display: grid; place-items: center; width: 50px; min-height: 48px; border: 1px solid #9ba99c; border-radius: 3px; font: 28px/1 var(--mono); }
.carry-digit[data-set], .flag-digit[data-set] { background: var(--accent); color: var(--paper); border-color: var(--accent); }
.stored-digits { display: grid; place-items: center; min-height: 48px; font: 28px/1 var(--mono); letter-spacing: .04em; }
.addition-explanation { margin: 20px 0 0; font-size: 14px; }
.experiment-note { margin-top: 12px; font-size: 13px; color: var(--muted); }
.lesson-navigation { max-width: 650px; margin: 40px auto 0; padding-top: 24px; border-top: 1px solid var(--line); display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); align-items: start; gap: 24px; }
.lesson-navigation a { font-size: 15px; color: #875037; overflow-wrap: break-word; }
.lesson-navigation a > span { display: block; margin-bottom: 6px; font: 11px/1.6 var(--mono); color: var(--muted); }
.lesson-previous { grid-column: 1; }
.lesson-all { grid-column: 2; }
.lesson-next { grid-column: 3; text-align: right; }
.lesson-groups { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px 30px; padding-block: 22px; border-block: 1px solid var(--line); }
.lesson-groups a { display: flex; justify-content: space-between; gap: 12px; font-size: 14px; }
.lesson-group { margin-top: 48px; }
.lesson-group .eyebrow { margin-bottom: 8px; }
.lesson-group h2 { font: 500 32px/1.2 var(--serif); letter-spacing: -.02em; margin-bottom: 12px; }
.lesson-group header > p:last-child { color: var(--muted); font-size: 15px; }
.lesson-list { list-style: none; padding: 0; margin: 24px 0 0; border-top: 1px solid var(--line); }
.lesson-list li { border-bottom: 1px solid var(--line); }
.lesson-list a { display: flex; justify-content: space-between; align-items: center; gap: 24px; padding: 18px 12px; text-decoration: none; }
.lesson-list a:hover { background: #f0eee5; }
.lesson-list strong { font-size: 17px; font-weight: 600; text-decoration: underline; text-underline-offset: .2em; }
.lesson-summary { display: block; margin-top: 4px; color: var(--muted); font-size: 14px; }
.lesson-arrow { color: var(--accent); font-size: 22px; }
@media (max-width: 520px) {
  .lesson-navigation { grid-template-columns: minmax(0, 1fr); gap: 20px; }
  .lesson-navigation a { grid-column: 1; text-align: left; }
  .lesson-groups { grid-template-columns: minmax(0, 1fr); }
  .lesson-list a { padding-inline: 4px; gap: 16px; }
}
@media (min-width: 1101px) {
  .wraparound-lesson { width: min(1100px, calc(100% - 112px)); }
  .byte-increment { display: grid; grid-template-columns: minmax(0, .8fr) minmax(0, 1.4fr); align-items: stretch; }
  .byte-increment .byte-addition { border-bottom: 1px solid #c6cec0; border-right: 0; padding-inline: 24px; }
  .byte-increment .byte-explorer { padding-inline: 24px; }
  .byte-increment .experiment-note { grid-column: 1 / -1; }
  .byte-increment .byte-representations { gap: 12px; }
  .byte-increment .byte-representations input { font-size: 18px; }
}
@media (max-width: 1100px) {
  .site-header, .home, .site-footer, .chapter-layout { width: calc(100% - 64px); }
  .hero { gap: 35px; }
  .processor-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .processor-card h3 { font-size: 26px; }
  .chapter-layout { grid-template-columns: 190px minmax(0, 1fr); gap: 35px; }
  .chapter-header h1 { font-size: 50px; }
  .lesson { width: min(860px, calc(100% - 64px)); }
}
@media (max-width: 760px) {
  .site-header, .home, .site-footer, .chapter-layout { width: calc(100% - 40px); }
  .site-header { min-height: 82px; gap: 16px; flex-wrap: wrap; padding-block: 18px; }
  .brand { font-size: 21px; gap: 8px; }
  .brand-mark { width: 25px; height: 28px; }
  .site-header nav { width: 100%; justify-content: space-between; gap: 16px; font-size: 12px; }
  .hero { grid-template-columns: 1fr; padding-block: 46px 50px; gap: 38px; }
  .hero h1 { font-size: clamp(40px, 8vw, 56px); }
  .hero-plate { width: min(480px, calc(100% - 8px)); justify-self: center; }
  .hero-intro { font-size: 16px; }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 16px; }
  .section-heading h2 { font-size: 36px; }
  .processor-card { padding: 20px 16px 15px; }
  .processor-card h3 { font-size: 23px; }
  .processor-card > p { font-size: 10px; }
  .about-section { grid-template-columns: 1fr; gap: 28px; padding-block: 45px; }
  .about-section h2 { font-size: 45px; }
  .about-section h2 br { display: none; }
  .about-section h2 br::after { content: ' '; }
  .site-footer { flex-wrap: wrap; gap: 12px; }
  .site-footer p:last-child { margin-left: 0; width: 100%; }
  .chapter-layout { display: block; margin-top: 24px; }
  .chapter-sidebar { position: static; max-height: none; padding: 0; margin-bottom: 35px; }
  .back-link { margin-bottom: 20px; }
  .contents { border: 1px solid var(--line); padding: 12px; }
  .contents nav { max-height: 180px; overflow: auto; }
  .chapter-header h1 { font-size: 45px; }
  .chapter-meta { flex-wrap: wrap; gap: 8px; }
  .chapter-prose { font-size: 15px; }
  .chapter-prose h2 { font-size: 29px; }
  .chapter-prose h3 { font-size: 24px; }
  .code-block pre { padding: 14px; font-size: 11px; }
  .architecture-diagram { padding: 10px; }
  .learn-section { grid-template-columns: 1fr; gap: 18px; }
  .lesson { width: calc(100% - 40px); margin-top: 35px; }
  .lesson-intro { font-size: 16px; }
  .byte-explorer, .byte-addition { padding: 20px; }
  .byte-bits { gap: 16px; }
  .nibble-bits { gap: 5px; }
  .byte-bit button { min-height: 48px; font-size: 26px; }
  .byte-representations { gap: 12px; }
  .byte-representations input { font-size: 16px; }
  .lesson-prose h2 { font-size: 28px; }
}
@media (max-width: 520px) {
  .instrument-heading { flex-direction: column; gap: 4px; }
  .byte-explorer, .byte-addition { padding: 16px 12px; }
  .byte-bits { gap: 12px; }
  .nibble-bits { gap: 3px; }
  .bit-weight { font-size: 10px; }
  .byte-sum { font-size: 15px; }
  .byte-representations { grid-template-columns: 1fr; gap: 16px; }
  .byte-representations label > span { display: inline; margin-left: 6px; }
  .byte-representations input { display: block; margin-top: 6px; font-size: 20px; }
  .addition-equation { font-size: 22px; }
  .addition-bits { gap: 12px; }
  .carry-result { padding-right: 12px; }
  .carry-result, .stored-result { font-size: 10px; }
  .carry-digit, .flag-digit { width: 40px; font-size: 24px; }
  .stored-digits { font-size: 22px; letter-spacing: 0; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }
@media print {
  .site-header, .site-footer, .chapter-sidebar, .state-map, .chapter-pagination { display: none; }
  body { background: white; color: black; }
  .chapter-layout { display: block; margin: 0; width: 100%; }
  .code-block pre { white-space: pre-wrap; overflow-wrap: anywhere; }
}

.memory-bank { border: 1px solid #c6cec0; border-bottom: 0; background: #fffefa; padding: 24px 30px; }
.memory-key { font-size: 14px; color: #53665b; }
.memory-bank fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
.memory-cells { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 10px; }
.memory-cell { border: 1px solid #9ba99c; border-radius: 3px; background: var(--paper); color: var(--ink); padding: 12px 4px; }
.memory-cell span { display: block; font: 11px/1.5 var(--mono); }
.memory-cell strong { display: block; font: 26px/1.6 var(--mono); }
.memory-cell[aria-pressed="true"] { outline: 2px solid var(--accent); outline-offset: 1px; background: #f5e4d4; }
.memory-cell:hover { border-color: var(--accent); }
.memory-status { font: 14px/1.6 var(--mono); margin: 18px 0 0; }
.memory-task { margin-block: 10px 0; }
@media (min-width: 1101px) {
  .memory-lesson { width: min(1100px, calc(100% - 112px)); }
  .memory-explorer { display: grid; grid-template-columns: minmax(0, .8fr) minmax(0, 1.4fr); }
  .memory-bank { border-bottom: 1px solid #c6cec0; border-right: 0; padding-inline: 24px; }
  .memory-explorer .byte-explorer { padding-inline: 24px; }
  .memory-explorer .byte-representations { gap: 12px; }
  .memory-explorer .byte-representations input { font-size: 18px; }
  .memory-cells { grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; }
  .memory-explorer .experiment-note, .memory-task { grid-column: 1 / -1; }
}
@media (max-width: 760px) { .memory-bank { padding: 20px; } }
@media (max-width: 520px) {
  .memory-bank { padding: 16px 12px; }
  .memory-cells { gap: 8px; }
  .memory-cell span { font-size: 9px; }
  .memory-cell strong { font-size: 22px; }
}

.register-workbench { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); }
.register-workbench .memory-bank { border-bottom: 1px solid #c6cec0; border-right: 0; }
.register-panel { padding: 24px 30px; background: var(--ink); color: var(--paper); }
.register-panel .instrument-heading { border-color: #6f8575; }
.register-panel h2 { font: 500 30px/1.2 var(--serif); margin-bottom: 12px; }
.register-value { display: flex; align-items: baseline; gap: 16px; font: 64px/1.2 var(--mono); margin: 0 0 16px; }
.register-unit { font: 12px var(--mono); }
.register-representations { margin: 0; font: 14px/1.8 var(--mono); }
.register-representations > div { display: flex; justify-content: space-between; gap: 16px; }
.register-representations dd { margin: 0; }
.register-panel > p:last-child { margin: 20px 0 0; font-size: 13px; }
.register-flag { display: flex; justify-content: space-between; align-items: center; gap: 16px; border-top: 1px solid #6f8575; padding-top: 16px; margin-top: 16px; font: 14px var(--mono); }
.register-actions { display: flex; flex-wrap: wrap; gap: 12px; border: 0; padding: 0; margin: 22px 0 16px; min-width: 0; }
.register-actions .button { border: 1px solid var(--ink); border-radius: 3px; }
.register-actions .clear-byte { margin: 0; }
.register-actions button:disabled { opacity: .45; }
.register-next { font-size: 14px; margin-bottom: 16px; }
.register-record { border-left: 3px solid var(--accent); padding: 15px 20px; background: #f0eee5; }
.register-record p { margin: 6px 0 0; font-size: 15px; }
.register-calculation { border: 1px solid #c6cec0; padding: 15px 20px; margin-top: 16px; background: #fffefa; }
.register-calculation p { margin: 6px 0 0; font-size: 15px; }
.program-view { border: 1px solid #c6cec0; padding: 24px; margin-top: 24px; background: #fffefa; }
.program-heading { display: flex; justify-content: space-between; align-items: start; gap: 20px; }
.program-heading h2 { font: 500 26px/1.3 var(--serif); margin: 0; }
.program-heading p, .program-key, .program-fetched { font-size: 13px; }
.program-heading p { margin: 8px 0 0; }
.program-counter { flex-shrink: 0; display: grid; gap: 4px; text-align: right; font: 11px/1.5 var(--mono); }
.program-counter strong { font-size: 30px; }
.program-key { margin-block: 18px; }
.program-key span { padding: 2px 4px; background: #f5e4d4; }
.program-edit { padding: 16px; margin-bottom: 20px; background: #f0eee5; border-left: 3px solid var(--accent); }
.program-edit label { display: block; font-size: 15px; margin-bottom: 8px; }
.program-edit label span { font-size: 12px; }
.program-edit input { width: 6ch; padding: 8px 10px; border: 1px solid #8a9a89; border-radius: 3px; font: 22px var(--mono); color: var(--ink); background: #fffefa; }
.program-edit input:disabled { opacity: .6; }
.program-edit select { max-width: 100%; padding: 10px; border: 1px solid #8a9a89; border-radius: 3px; font: 14px var(--mono); color: var(--ink); background: #fffefa; }
.program-edit select:disabled { opacity: .6; }
.program-edit input[aria-invalid] { border-color: #a33426; }
.program-edit p { font-size: 13px; margin: 10px 0 0; }
.program-edit .input-error { color: #a33426; }
.program-edit .input-error:empty { display: none; }
.program-edit code { font-family: var(--mono); }
.program-instructions { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
.program-two-columns { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.program-instructions > li { border: 1px solid var(--line); padding: 12px; }
.program-instructions > li[data-skipped] { border-style: dashed; }
.program-instructions > li[aria-current="step"] { outline: 2px solid var(--ink); outline-offset: 1px; }
.program-instruction-heading { min-height: 65px; font-size: 13px; line-height: 1.5; }
.program-marker { display: block; min-height: 20px; font: 11px/1.6 var(--mono); color: var(--accent); }
.program-runs:not([hidden]) { display: block; font: 11px/1.6 var(--mono); }
.program-instructions code { font: 12px/1.5 var(--mono); }
.program-bytes { display: flex; gap: 6px; margin-top: 12px; }
.program-byte { display: grid; gap: 4px; flex: 0 1 56px; text-align: center; padding: 6px 2px; background: var(--paper); border: 1px solid var(--line); }
.program-byte span { font: 10px/1.5 var(--mono); }
.program-byte strong { font: 22px/1.3 var(--mono); }
.program-byte[data-fetched] { background: #f5e4d4; border-color: var(--accent); }
.program-end { border-left: 3px solid var(--line); padding: 10px 12px; margin: 16px 0; font: 12px/1.5 var(--mono); }
.program-end[data-current] { border-color: var(--ink); background: #e8eee7; }
.program-fetched { margin: 0; }
.program-path { font: 12px/1.8 var(--mono); margin: 12px 0 0; }
@media (max-width: 760px) {
  .program-view { padding: 20px; }
  .program-heading { flex-wrap: wrap; gap: 12px; }
  .program-counter { text-align: left; }
  .program-instructions { grid-template-columns: 1fr; }
  .program-instructions > li { display: grid; grid-template-columns: minmax(0, 1fr) 148px; column-gap: 10px; }
  .program-instruction-heading { min-height: 0; grid-column: 1; }
  .program-instructions code { grid-column: 1; }
  .program-bytes { width: 148px; grid-column: 2; grid-row: 1 / span 2; align-self: center; gap: 4px; margin: 0; }
  .program-byte { flex-basis: 46px; }
}
@media (max-width: 520px) { .program-view { padding: 16px 12px; } }
.memory-edit, .register-inside { margin-top: 24px; }
.memory-edit > summary, .register-inside > summary { cursor: pointer; font-size: 15px; padding-block: 12px; }
.memory-edit .experiment-note { margin-top: 0; }
.register-inside { border-top: 1px solid var(--line); font-size: 14px; }
.register-inside p { margin-top: 16px; }
.register-inside pre { overflow-x: auto; background: #f0eee5; padding: 18px; font: 12px/1.8 var(--mono); }
.register-inside code { font-family: var(--mono); }
@media (min-width: 1101px) { .register-lesson { width: min(1000px, calc(100% - 112px)); } }
@media (max-width: 760px) {
  .register-workbench { grid-template-columns: 1fr; }
  .register-workbench .memory-bank { border-right: 1px solid #c6cec0; border-bottom: 0; }
  .register-panel { padding: 20px; }
  .register-actions { flex-direction: column; align-items: stretch; }
  .register-actions .button { justify-content: center; }
}
@media (max-width: 520px) {
  .register-panel { padding: 16px 12px; }
  .register-value { font-size: 48px; }
  .register-representations { font-size: 12px; }
}

.altair-explorer fieldset, .basic-panel fieldset { border: 0; margin: 0; padding: 0; min-width: 0; }
.altair-explorer [hidden], .basic-machine [hidden] { display: none; }
.altair-panel { padding: 9px; background: #294a62; border: 1px solid #193346; border-radius: 5px; box-shadow: 0 8px 20px #233b3f18; }
.panel-title { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 14px 18px 20px; color: #f9f6e9; }
.panel-title h2 { margin: 0; font: 20px/1.3 var(--mono); letter-spacing: .08em; }
.panel-title h2 strong { font-weight: 400; color: #bbd2dd; }
.panel-title > span { font: 11px/1.5 var(--mono); text-align: right; }
.panel-face { padding: 24px; background: #eeeade; border-radius: 2px; }
.panel-face h3 { display: flex; justify-content: space-between; align-items: baseline; flex-wrap: wrap; gap: 6px 16px; font: 600 13px/1.5 var(--mono); text-transform: uppercase; margin: 0 0 14px; }
.panel-face h3 span { font: 12px/1.5 system-ui, sans-serif; text-transform: none; color: #53665b; }
.panel-banks { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.panel-bit-bank { display: grid; grid-template-columns: repeat(8, minmax(0, 1fr)); gap: 5px; }
.panel-lamp { display: grid; justify-items: center; gap: 8px; font: 10px/1.4 var(--mono); }
.panel-lamp strong { display: grid; place-items: center; width: 25px; height: 25px; border-radius: 50%; border: 2px solid #4d3832; color: #d2c5be; background: #3e2724; font: 12px/1 var(--mono); }
.panel-lamp[data-on] strong { color: #fff7e9; background: #c74128; border-color: #923520; box-shadow: 0 0 9px #e5582e80, inset 0 1px 3px #ffd19190; }
.panel-number { margin: 14px 0 0; font: 13px/1.6 var(--mono); }
.panel-data-lights { margin-top: 22px; margin-left: auto; max-width: calc((100% - 24px) / 2); }
.panel-data-lights h3 { display: block; }
.panel-data-lights h3 span { display: block; margin-top: 3px; }
.panel-light-key { font-size: 12px; color: #53665b; margin: 16px 0 22px; }
.panel-switch-bank { border-top: 1px solid #b6b8ac; padding-top: 20px; }
.panel-bank-label { font: 11px/1.4 var(--mono); margin: 0 0 10px; }
.panel-switch { display: grid; justify-items: center; gap: 5px; padding: 8px 0; min-width: 0; border: 1px solid #aaa99d; border-radius: 4px; background: #f8f5ed; color: #304539; font: 11px/1.4 var(--mono); cursor: pointer; }
.panel-switch strong { font-weight: 400; }
.panel-switch[aria-pressed="true"] { background: #e0dfce; border-color: #6f7e70; }
.panel-switch:enabled:hover { border-color: #875037; }
.panel-toggle { position: relative; width: 12px; height: 24px; border: 1px solid #666e6b; border-radius: 8px; background: #535d5a; box-shadow: inset 0 1px 3px #142b2060; }
.panel-toggle::after { content: ''; position: absolute; inset: 1px 1px auto; height: 10px; border: 1px solid #838b89; border-radius: 4px; background: linear-gradient(#fff, #bec5c1); transform: translateY(9px); transition: transform .12s; }
.panel-switch[aria-pressed="true"] .panel-toggle::after { transform: translateY(0); }
.panel-switch-numbers { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px 24px; font: 12px/1.6 var(--mono); margin: 16px 0 0; }
.panel-switch-numbers dt { font: 12px/1.6 system-ui, sans-serif; color: #53665b; }
.panel-switch-numbers dd { margin: 4px 0 0; }
.panel-reminder { font-size: 13px; margin: 18px 0; }
.panel-operations { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px 24px; border-top: 1px solid #b6b8ac; padding-top: 20px; }
.panel-operations button { min-height: 44px; width: 100%; padding: 10px 6px; border: 1px solid #264357; border-radius: 3px; color: #fff9eb; background: #294a62; font: 12px/1.5 var(--mono); cursor: pointer; }
.panel-operations button:enabled:hover { background: #18374c; }
.panel-operations p { font-size: 12px; margin: 8px 0 0; }
.altair-explorer button:disabled, .basic-panel button:disabled { opacity: .5; cursor: default; }
.panel-guide-toggle { display: flex; align-items: center; gap: 10px; margin-top: 24px; font-size: 14px; min-height: 44px; }
.panel-guide-toggle input { width: 18px; height: 18px; accent-color: #294a62; }
.panel-preview { font-size: 14px; margin: 12px 0 18px; }
.altair-explorer .register-record { margin-top: 16px; }
.panel-reference { margin-bottom: 24px; padding: 18px 20px; border: 1px solid var(--line); background: #f5f1e5; }
.panel-reference summary { cursor: pointer; font-weight: 600; }
.panel-reference summary span { display: block; margin-top: 6px; font-size: 12px; font-weight: 400; }
.panel-reference table { width: 100%; border-collapse: collapse; margin-top: 16px; font: 13px/1.6 var(--mono); }
.panel-reference caption { text-align: left; font: 13px/1.6 system-ui, sans-serif; margin-bottom: 12px; }
.panel-reference th, .panel-reference td { text-align: left; padding: 7px 8px; border-bottom: 1px solid var(--line); }
.panel-reference tbody th { font-weight: 400; }
.panel-reference td:last-child { font: 12px/1.5 system-ui, sans-serif; }
.panel-reference tr[aria-current] { background: #e0e6da; }
.panel-reference p { font-size: 13px; margin: 14px 0 0; }
.panel-reference code { font-family: var(--mono); }
.panel-entry-hint { padding: 12px; background: #f9f6ed; border-left: 3px solid #294a62; font: 12px/1.7 var(--mono); }
.panel-processor { margin: 24px 0; padding: 24px; border: 1px solid #bdc8ba; background: #eef1e6; }
.panel-processor h3 { margin: 0; font-size: 20px; }
.panel-cpu-state { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; margin: 20px 0; }
.panel-cpu-state dt { font: 13px/1.6 var(--mono); }
.panel-cpu-state dt span { display: block; font: 11px/1.6 system-ui, sans-serif; color: #53665b; }
.panel-cpu-state dd { margin: 6px 0 0; font: 32px/1.3 var(--mono); }
.panel-processor > p { font-size: 14px; }
.panel-run-controls { display: flex; flex-wrap: wrap; align-items: end; gap: 12px; margin: 18px 0 12px; }
.panel-run-controls label { display: grid; gap: 6px; font-size: 12px; }
.panel-run-controls select { max-width: 100%; min-height: 44px; padding: 8px; border: 1px solid #8a9a89; background: #fffefa; color: var(--ink); font: 13px var(--mono); }
.panel-zero { font: 13px/1.6 var(--mono); }
.panel-history { padding-left: 32px; font-size: 13px; line-height: 1.8; }
.panel-history li + li { margin-top: 8px; }
.byte-output { padding: 20px; border: 1px solid #7e704f; border-radius: 4px; background: #343c36; color: #f8efd9; }
.byte-output h4 { margin: 0 0 18px; font: 16px/1.5 var(--mono); }
.byte-output h4 span { display: block; margin-top: 4px; font: 12px/1.5 system-ui, sans-serif; color: #e0d4b8; }
.byte-output .panel-bit-bank { max-width: 420px; }
.byte-output .panel-lamp strong { background: #473e2c; border-color: #8e7c53; color: #dfd3b7; }
.byte-output .panel-lamp[data-on] strong { background: #e6af3a; border-color: #f1d281; color: #302b1c; box-shadow: 0 0 12px #f4ba4460; }
.byte-output p { font-size: 12px; line-height: 1.7; margin: 12px 0 0; }
.byte-output .output-status { font: 14px/1.7 var(--mono); }
.panel-cpu-state-five { grid-template-columns: repeat(5, minmax(0, 1fr)); }
.panel-cpu-state-three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.panel-devices { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; align-items: start; }
.ram-window { background: #e2ebed; border: 1px solid #9fadb4; border-radius: 4px; padding: 18px; min-width: 0; }
.ram-window h4 { margin: 0 0 12px; font: 17px/1.5 var(--mono); }
.ram-window table { width: 100%; border-collapse: collapse; font: 12px/1.5 var(--mono); }
.ram-window caption { text-align: left; font: 11px/1.6 system-ui, sans-serif; padding-bottom: 10px; }
.ram-window th, .ram-window td { text-align: left; padding: 8px 4px; border-bottom: 1px solid #bdcbd0; }
.ram-window tbody th { font-weight: 400; }
.ram-window [data-ram-pointer] { display: inline-block; min-width: 2.8em; font-size: 10px; font-weight: 700; }
.ram-window [aria-current="location"] { background: #f5e4d4; outline: 2px solid var(--accent); }
.ram-window p { font-size: 12px; line-height: 1.7; margin: 12px 0 0; }
.byte-input { padding: 20px; border: 1px solid #8ca4af; border-radius: 4px; background: #e0e9eb; }
.byte-input h4 { margin: 0 0 16px; font: 16px/1.5 var(--mono); }
.byte-input h4 span { display: block; margin-top: 4px; font: 12px/1.5 system-ui, sans-serif; }
.byte-input .panel-bit-bank { max-width: 420px; }
.byte-input p { margin: 12px 0; font-size: 12px; line-height: 1.7; }
.byte-input .input-label { font-weight: 600; }
.byte-input .input-number { font: 12px/1.7 var(--mono); }
.byte-input .input-status { padding: 12px; background: #f5f8f4; border-left: 3px solid #527585; font: 14px/1.7 var(--mono); }
@media (max-width: 680px) {
  .panel-devices { grid-template-columns: 1fr; }
  .panel-banks, .panel-switch-numbers { grid-template-columns: 1fr; gap: 16px; }
  .panel-data-lights { max-width: none; }
  .panel-face { padding: 20px 12px; }
  .panel-title { flex-direction: column; align-items: start; gap: 8px; padding: 12px 12px 18px; }
  .panel-title > span { text-align: left; }
  .panel-bit-bank { gap: 3px; }
  .panel-operations { gap: 16px 12px; }
}
@media (prefers-reduced-motion: reduce) { .panel-toggle::after { transition: none; } }
@media (max-width: 520px) {
  .panel-reference, .panel-processor { padding: 16px 12px; }
  .byte-output, .byte-input { padding: 16px 10px; }
  .panel-reference th, .panel-reference td { padding: 6px 3px; font-size: 11px; }
  .panel-cpu-state { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

.ascii-panel { padding: 24px 30px; border: 1px solid #c6cec0; border-bottom: 0; background: #fffefa; }
.ascii-reading { display: grid; grid-template-columns: 120px minmax(0, 1fr); gap: 24px; align-items: center; }
.ascii-glyph { display: grid; place-items: center; min-height: 120px; border: 1px solid #bdc8ba; background: #eef1e6; font: 28px/1 var(--mono); }
.ascii-glyph[data-kind="graphic"] { font-size: 72px; }
.ascii-reading h2 { margin: 0 0 8px; font-size: 20px; }
.ascii-reading p { margin: 0; font-size: 14px; }
.ascii-reading .byte-error { margin-top: 10px; }
.ascii-examples { display: flex; flex-wrap: wrap; gap: 10px; border: 0; padding: 0; margin: 20px 0 0; min-width: 0; }
.ascii-examples legend { margin-bottom: 10px; font-size: 13px; }
.ascii-examples button { min-height: 44px; border: 1px solid #9ba99c; border-radius: 3px; background: var(--paper); color: var(--ink); font: 16px/1.4 var(--mono); padding: 8px 12px; cursor: pointer; }
.ascii-examples button span { display: block; font: 11px/1.6 system-ui, sans-serif; }
.ascii-examples button[aria-pressed="true"] { background: #e0e6da; border-color: var(--ink); }
.ascii-examples button:enabled:hover { border-color: var(--accent); }
.ascii-examples:disabled button { opacity: .6; cursor: default; }
@media (max-width: 760px) { .ascii-panel { padding: 20px; } }
@media (max-width: 520px) {
  .ascii-panel { padding: 16px 12px; }
  .ascii-reading { grid-template-columns: 70px minmax(0, 1fr); gap: 12px; align-items: start; }
  .ascii-glyph { min-height: 80px; font-size: 22px; }
  .ascii-glyph[data-kind="graphic"] { font-size: 48px; }
  .ascii-reading h2 { font-size: 17px; }
}

.character-input label { display: block; font-size: 13px; font-weight: 600; }
.character-input textarea { display: block; width: 100%; min-width: 0; margin-top: 8px; padding: 8px 12px; border: 1px solid #8ca4af; background: var(--paper); color: var(--ink); font: 28px/1.4 var(--mono); resize: none; }
.character-input textarea[aria-invalid="true"] { border: 2px solid var(--accent); padding: 7px 11px; }
.character-controls { display: flex; flex-wrap: wrap; gap: 10px; }
.character-controls .button { font-size: 12px; padding: 12px; }
.terminal-output { padding: 20px; border: 1px solid #52655a; border-radius: 4px; background: #293e34; color: #f0f3da; min-width: 0; }
.panel-processor > .terminal-output { margin-top: 20px; }
.terminal-output h4 { margin: 0 0 16px; font: 16px/1.5 var(--mono); }
.terminal-output h4 span { display: block; margin-top: 4px; font: 12px/1.5 system-ui, sans-serif; }
.terminal-output p { margin: 12px 0; font-size: 12px; line-height: 1.7; }
.terminal-screen { position: relative; }
.terminal-screen pre { height: 180px; margin: 0; padding: 12px; overflow: auto; white-space: pre-wrap; overflow-wrap: anywhere; background: #172b22; color: #eff4d7; font: 20px/1.5 var(--mono); }
.terminal-screen pre::after { content: '▏'; opacity: .6; }
.terminal-screen [data-terminal-empty] { position: absolute; left: 28px; top: 15px; font-size: 12px; color: #becabd; pointer-events: none; }
@media (max-width: 520px) { .terminal-output { padding: 16px 10px; } }

/* The full machine keeps terminal controls distinct from the instruction lessons. */
.basic-machine { margin-block: 32px 48px; padding: 26px; border: 1px solid var(--line); background: #f1efe7; }
.basic-machine > h2 { font: 500 34px/1.2 var(--serif); margin-bottom: 16px; }
.basic-machine .eyebrow { margin-bottom: 10px; }
.basic-machine > p { font-size: 14px; }
.basic-media { display: grid; gap: 16px; margin-block: 24px 12px; }
.basic-media label, .basic-keyboard { display: grid; gap: 8px; font-size: 13px; }
.basic-media input[type=file] { width: 100%; min-width: 0; font-size: 13px; }
.basic-machine progress { display: block; width: 100%; height: 8px; accent-color: var(--ink); }
.basic-controls { display: flex; flex-wrap: wrap; gap: 9px; margin-block: 14px; }
.basic-controls button { padding: 9px 13px; border: 1px solid #b8c5b9; background: var(--paper); color: var(--ink); font-size: 12px; }
.basic-controls button:first-child { background: var(--ink); color: white; }
.basic-controls button:disabled { opacity: .45; }
.basic-machine .basic-readout { font: 11px/1.7 var(--mono); overflow-wrap: anywhere; margin-block: 10px 16px; }
.serial-screen { height: 360px; overflow: auto; margin: 0 0 18px; padding: 20px; background: #20342d; color: #edf0cd; font: 13px/1.5 var(--mono); tab-size: 8; border: 1px solid #13271e; }
.basic-keyboard textarea { width: 100%; resize: vertical; min-height: 44px; padding: 10px; border: 1px solid #b8c5b9; background: var(--paper); color: var(--ink); font: 14px var(--mono); }
.basic-machine .basic-hint { font-size: 12px; color: var(--muted); line-height: 1.65; }
.basic-example { margin-block: 24px; padding: 16px 20px; border-left: 3px solid var(--accent); background: #efefe7; }
.basic-example .basic-example-label { font: 12px/1.6 system-ui, sans-serif; color: var(--muted); margin: 0 0 6px; }
.basic-example pre { margin: 0; overflow-x: auto; font: 14px/1.7 var(--mono); }
.basic-example pre + .basic-example-label { margin-top: 16px; }
.basic-example pre code { padding: 0; background: none; font: inherit; }
.basic-message { min-height: 1.6em; color: var(--accent); }
.basic-panel, .basic-inspection { margin-block: 22px; }
.basic-panel { container-type: inline-size; }
.basic-panel > summary { cursor: pointer; font-size: 13px; margin-bottom: 16px; }
.basic-inspection summary { cursor: pointer; font-size: 13px; }
.basic-inspection pre { overflow: auto; font: 12px/1.6 var(--mono); }
.rom-controls { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: end; gap: 12px; margin-block: 18px; }
.rom-controls label { display: grid; gap: 6px; font-size: 12px; }
.rom-controls input, .rom-controls select, .rom-controls button { min-width: 0; min-height: 44px; padding: 8px; border: 1px solid #b8c5b9; border-radius: 3px; background: var(--paper); color: var(--ink); font: 12px var(--mono); }
.rom-controls :disabled { opacity: .45; }
.rom-current { min-height: 3.2em; white-space: pre-line; font: 13px/1.6 var(--mono); }
@media (max-width: 480px) { .rom-controls { grid-template-columns: minmax(0, 1fr); } }
@media (max-width: 700px) {
  .basic-machine { padding: 18px 14px; }
  .basic-machine > h2 { font-size: 28px; }
  .serial-screen { padding: 12px; font-size: 12px; height: 320px; }
}

@container (max-width: 600px) {
  .panel-banks, .panel-switch-numbers { grid-template-columns: 1fr; gap: 16px; }
  .panel-data-lights { max-width: none; margin-left: 0; }
}

/* Machine guides share the catalogue cards; the Apple II owns a RAM-backed screen. */
.machine-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.apple2-display-surround { container-type: inline-size; margin: 24px 0 12px; padding: 16px; border: 1px solid #b9ac93; border-radius: 10px; background: #e6dcc6; }
.apple2-display-label { display: flex; justify-content: space-between; gap: 12px; margin-bottom: 12px; color: #4e493e; font: 600 11px/1.4 var(--mono); letter-spacing: .08em; }
.apple2-screen { display: grid; aspect-ratio: 4 / 3; padding: 4%; background: #000; border-radius: 5px; font-family: var(--mono); font-size: min(2.5cqw, 22px); line-height: 1; overflow: hidden; }
.apple2-raster { position: relative; display: grid; grid-template-rows: repeat(24, minmax(0, 1fr)); min-width: 0; min-height: 0; }
.apple2-raster > canvas { position: absolute; inset: 0; width: 100%; height: 100%; image-rendering: pixelated; pointer-events: none; }
.apple2-row { position: relative; display: grid; grid-template-columns: repeat(40, minmax(0, 1fr)); min-height: 0; }
.apple2-row > span { white-space: pre; text-align: center; align-content: center; color: transparent; }
.apple2-row > span::selection { color: transparent; background: #659ad480; }
.apple2-scanlines::after { content: ""; position: absolute; inset: 0; pointer-events: none; background: repeating-linear-gradient(to bottom, transparent 0, transparent var(--scanline-clear), #00000073 var(--scanline-clear), #00000073 var(--scanline-row)); }
.apple2-display-options { display: flex; justify-content: flex-end; flex-wrap: wrap; gap: 8px 16px; font-size: 12px; }
.apple2-display-options label { display: flex; align-items: center; gap: 6px; cursor: pointer; }
.apple2-display-options input { accent-color: var(--accent); }
.apple2-screen:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }
.apple2-cpu-value { white-space: nowrap; }
.apple2-cpu-value.is-changed, .apple2-memory-byte.is-changed { background: #f6dfab; color: #513907; border-radius: 2px; text-decoration: underline; text-decoration-thickness: 2px; text-underline-offset: 3px; }
.apple2-machine textarea { box-sizing: border-box; width: 100%; resize: vertical; min-height: 48px; font: 15px/1.5 var(--mono); }
@media (max-width: 700px) {
  .machine-grid { grid-template-columns: 1fr; }
  .apple2-display-surround { padding: 8px; }
  .apple2-display-label { font-size: 9px; }
}