:root {
  color-scheme: light;
  --text: #1b1a18;
  --ink: #171715;
  --ink-2: #1d1d1a;
  --ink-3: #292824;
  --paper: #f4f1ea;
  --paper-2: #e8e4dc;
  --white: #e8e4dc;
  --surface: #e8e4dc;
  --active-bg: #1b1a18;
  --active-text: #eeeae2;
  --purple: #1b1a18;
  --purple-dark: #6f6a62;
  --purple-pale: #1b1a18;
  --lavender: #c9c2b7;
  --muted: #6b655d;
  --line: #c9c2b7;
  --digital: #b786ff;
  --analog: #f2b84b;
  --success: #2f7d61;
  --danger: #8f343e;
  --radius: 0;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --text: #eeeae2;
  --paper: #11110f;
  --paper-2: #1d1d1a;
  --white: #1d1d1a;
  --surface: #1d1d1a;
  --active-bg: #eeeae2;
  --active-text: #171715;
  --purple: #eeeae2;
  --purple-dark: #aaa59b;
  --purple-pale: #eeeae2;
  --muted: #aaa59b;
  --line: #48453f;
  --danger: #d27d84;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--text);
  background: var(--paper);
  font-family: Montserrat, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}

button, a { -webkit-tap-highlight-color: transparent; }
button { font: inherit; }
a { color: inherit; }

:focus-visible {
  outline: 3px solid var(--analog);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: 12px;
  padding: 10px 14px;
  color: white;
  background: var(--ink);
  border-radius: 0;
  transform: translateY(-160%);
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  width: min(1240px, calc(100% - 40px));
  margin: 0 auto;
  min-height: 86px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
  border-bottom: 1px solid var(--line);
}

.header-actions { justify-self: end; display: flex; align-items: center; gap: 24px; }
.page-label { color: var(--muted); font-size: .68rem; font-weight: 500; letter-spacing: .13em; }

.theme-toggle {
  min-width: 74px;
  height: 33px;
  padding: 8px 10px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  border: 1px solid var(--line);
  border-radius: 0;
  color: var(--muted);
  background: transparent;
  cursor: pointer;
  font-size: .58rem;
  font-weight: 600;
  letter-spacing: .08em;
}
.theme-toggle:hover { color: var(--text); border-color: var(--text); }
.theme-toggle svg { width: 12px; height: 12px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.theme-toggle .sun-icon { display: none; }
.theme-toggle .moon-icon { display: block; }
html[data-theme="dark"] .theme-toggle .sun-icon { display: block; }
html[data-theme="dark"] .theme-toggle .moon-icon { display: none; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  text-decoration: none;
  font-size: .82rem;
  letter-spacing: .12em;
  font-weight: 700;
}

.brand-mark { position: relative; display: inline-block; flex: 0 0 auto; width: 34px; height: 34px; background: var(--ink); }
.brand-mark img { position: absolute; inset: 7px; width: calc(100% - 14px); height: calc(100% - 14px); object-fit: contain; }
.brand-mark .logo-black { display: none; }
.brand-mark .logo-white { display: block; }
html[data-theme="dark"] .brand-mark { background: #eeeae2; }
html[data-theme="dark"] .brand-mark .logo-black { display: block; }
html[data-theme="dark"] .brand-mark .logo-white { display: none; }

nav { display: flex; gap: 24px; font-size: .64rem; font-weight: 500; letter-spacing: .08em; text-transform: uppercase; }
nav a { text-decoration: none; border-bottom: 1px solid transparent; }
nav a:hover { border-color: currentColor; }

main { overflow: clip; }

.intro {
  width: min(1240px, calc(100% - 40px));
  margin: 0 auto;
  padding: 72px 0 42px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: .68rem;
  line-height: 1.2;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
}

h1, h2, h3, p { text-wrap: pretty; }
h1, h2, h3 { margin-top: 0; line-height: 1.05; letter-spacing: -.035em; }

h1 {
  max-width: 940px;
  margin-bottom: 22px;
  font-family: Montserrat, ui-sans-serif, system-ui, sans-serif;
  font-size: clamp(3rem, 6.5vw, 6rem);
  font-weight: 700;
  line-height: .96;
  letter-spacing: -.065em;
}

.lede { max-width: 740px; margin: 0; color: var(--muted); font-size: clamp(1rem, 2vw, 1.2rem); }

.chain-key { display: flex; flex-wrap: wrap; gap: 22px; margin-top: 28px; color: var(--muted); font-size: .75rem; font-weight: 700; }
.chain-key span { display: inline-flex; align-items: center; gap: 8px; }
.line { display: inline-block; width: 32px; height: 0; border-top: 3px solid; }
.line.digital { border-color: var(--digital); border-top-style: dashed; }
.line.analog { border-color: var(--analog); }

.builder {
  width: min(1320px, calc(100% - 84px));
  margin: 0 auto;
  padding: 0;
  background: transparent;
  border: 0;
  border-radius: 0;
  box-shadow: none;
}

.builder-head, .chooser-title {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
}

.builder-head h2 { margin-bottom: 0; font: 700 clamp(2rem, 4vw, 3.4rem)/1.02 Montserrat, sans-serif; letter-spacing: -.055em; }

.text-button, .remove-button {
  border: 0;
  border-bottom: 1px solid currentColor;
  padding: 3px 0;
  color: var(--muted);
  background: transparent;
  font-size: .76rem;
  font-weight: 600;
  cursor: pointer;
}
.text-button:hover, .remove-button:hover { color: var(--purple-dark); }
.remove-button { color: var(--danger); }

.builder-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.75fr) minmax(280px, .72fr);
  gap: 20px;
  margin-top: 28px;
}

.workspace {
  padding: 26px;
  background: var(--surface);
}

.control-bar {
  display: grid;
  grid-template-columns: 1fr 1.28fr;
  gap: 16px;
  margin-bottom: 18px;
}

fieldset { min-width: 0; margin: 0; padding: 0; border: 0; }
legend { margin-bottom: 8px; color: var(--muted); font-size: .68rem; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; }

.segmented {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
}

.segmented button {
  min-height: 42px;
  padding: 8px 12px;
  border: 0;
  border-radius: 0;
  color: var(--muted);
  background: transparent;
  font-size: .78rem;
  font-weight: 600;
  cursor: pointer;
}
.segmented button + button { border-left: 1px solid var(--line); }
.segmented button[aria-pressed="true"] { color: var(--active-text); background: var(--active-bg); box-shadow: none; }

.change-notice {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin: 0 0 16px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 0;
  color: var(--text);
  background: var(--paper);
  font-size: .78rem;
}
.change-notice[hidden] { display: none; }
.change-notice p { margin: 0; }
.notice-actions { display: flex; flex: 0 0 auto; gap: 8px; }
.notice-actions button { padding: 8px 11px; border: 1px solid var(--line); border-radius: 0; color: var(--text); background: transparent; cursor: pointer; font-size: .72rem; font-weight: 600; }
.notice-actions .apply { border-color: var(--active-bg); color: var(--active-text); background: var(--active-bg); }

.scene-frame {
  position: relative;
  overflow: hidden;
  border: 0;
  border-radius: 0;
  background: #1b181e;
  box-shadow: none;
}

.desk-scene { display: block; width: 100%; height: auto; aspect-ratio: 920 / 520; }
.scene-hint { position: absolute; right: 14px; bottom: 10px; margin: 0; padding: 6px 9px; border-radius: 0; color: #c7bdcb; background: rgba(17, 14, 20, .78); font-size: .65rem; }

.device { cursor: pointer; }
.device .focus-ring { fill: transparent; stroke: transparent; stroke-width: 4; }
.device:hover .focus-ring, .device.selected .focus-ring { stroke: var(--purple); filter: url(#glow); }
.device:focus-visible { outline: none; }
.device:focus-visible .focus-ring { stroke: var(--analog); }
.device-label rect { fill: rgba(17, 14, 20, .9); stroke: rgba(255,255,255,.16); }
.device-label text { fill: white; font: 700 12px Montserrat, sans-serif; letter-spacing: .04em; }
.device-label .role-text { fill: #c9b8dd; font-size: 9px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; }
.led { fill: #b98aff; filter: url(#glow); }

.cable-digital { fill: none; stroke: var(--digital); stroke-width: 5; stroke-dasharray: 11 9; stroke-linecap: round; opacity: .95; }
.cable-analog { fill: none; stroke: var(--analog); stroke-width: 5; stroke-linecap: round; opacity: .95; }
.cable-under { fill: none; stroke: #0c0b0e; stroke-width: 10; stroke-linecap: round; opacity: .82; }
.cable-label rect { fill: #17141b; stroke: #4c4351; }
.cable-label text { fill: #e8e0eb; font: 600 10px Montserrat, sans-serif; }
.cable-label.digital rect { stroke: var(--digital); }
.cable-label.analog rect { stroke: var(--analog); }

.signal-summary {
  display: flex;
  align-items: center;
  gap: 15px;
  padding: 13px 4px;
  border-bottom: 1px solid var(--line);
}
.summary-label { color: var(--muted); font-size: .65rem; font-weight: 600; text-transform: uppercase; letter-spacing: .1em; }
.signal-summary p { margin: 0; font: 600 1rem Montserrat, sans-serif; letter-spacing: -.025em; }

.setup-chooser { padding-top: 22px; }
.chooser-title { align-items: center; }
.chooser-title h3 { margin-bottom: 0; font-size: 1.2rem; }

.setup-options { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 9px; margin-top: 14px; }
.setup-card {
  position: relative;
  min-height: 130px;
  padding: 15px;
  text-align: left;
  border: 1px solid var(--line);
  border-radius: 0;
  color: var(--text);
  background: transparent;
  cursor: pointer;
}
.setup-card:hover { border-color: var(--text); background: var(--paper); }
.setup-card[aria-pressed="true"] { border-color: var(--active-bg); color: var(--active-text); background: var(--active-bg); box-shadow: none; }
.setup-card .setup-action { display: block; margin-bottom: 20px; color: var(--muted); font-size: .62rem; font-weight: 600; letter-spacing: .1em; text-transform: uppercase; }
.setup-card strong { display: block; margin-bottom: 5px; font-size: .84rem; line-height: 1.25; }
.setup-card small { display: block; color: var(--muted); font-size: .66rem; line-height: 1.35; }
.setup-card[aria-pressed="true"] small,
.setup-card[aria-pressed="true"] .setup-action { color: var(--active-text); opacity: .72; }

.inspector { padding: 27px 26px 25px; background: var(--surface); }
.inspector-sticky { position: sticky; top: 24px; }
.inspector h2 { margin-bottom: 16px; font: 700 clamp(2rem, 4vw, 3.2rem)/1 Montserrat, sans-serif; letter-spacing: -.05em; }
.inspector > div > p:not(.eyebrow) { color: var(--muted); }

.connection-note { margin: 24px 0 30px; }
.connection-note > div { padding: 13px 0; border-top: 1px solid var(--line); }
.connection-note dt { margin-bottom: 4px; color: var(--muted); font-size: .65rem; font-weight: 600; letter-spacing: .1em; text-transform: uppercase; }
.connection-note dd { margin: 0; font-size: .8rem; font-weight: 600; }

.need-list { padding: 20px 0 0; border-top: 1px solid var(--line); border-radius: 0; background: transparent; color: var(--text); }
.need-list .eyebrow { color: var(--muted); }
.need-list h3 { margin-bottom: 14px; font: 600 1.15rem Montserrat, sans-serif; letter-spacing: -.025em; }
.need-list ul { margin: 0; padding: 0; list-style: none; }
.need-list li { position: relative; padding: 8px 0 8px 22px; border-top: 1px solid var(--line); font-size: .75rem; }
.need-list li::before { content: "✓"; position: absolute; left: 0; color: var(--muted); font-weight: 700; }
.compatibility-note { margin: 15px 0 0; color: var(--muted); font-size: .64rem; line-height: 1.45; }

.learn {
  width: min(1240px, calc(100% - 40px));
  margin: 0 auto;
  padding: 110px 0 88px;
  display: grid;
  grid-template-columns: .72fr 1.28fr;
  gap: 80px;
}

.learn-intro { position: sticky; top: 35px; align-self: start; }
.learn-intro h2 { margin-bottom: 20px; font: 700 clamp(2.2rem, 4.5vw, 4.5rem)/1 Montserrat, sans-serif; letter-spacing: -.06em; }
.learn-intro > p:last-child { max-width: 480px; color: var(--muted); }

.lesson { border-top: 1px solid var(--line); }
.lesson:last-child { border-bottom: 1px solid var(--line); }
.lesson summary {
  min-height: 96px;
  display: grid;
  grid-template-columns: 105px 1fr 24px;
  gap: 16px;
  align-items: center;
  padding: 18px 0;
  cursor: pointer;
  list-style: none;
}
.lesson summary::-webkit-details-marker { display: none; }
.lesson summary span { color: var(--muted); font-size: .62rem; font-weight: 600; letter-spacing: .09em; text-transform: uppercase; }
.lesson summary strong { font: 600 clamp(1.1rem, 2.2vw, 1.5rem) Montserrat, sans-serif; letter-spacing: -.035em; }
.lesson summary::after { content: "+"; color: var(--muted); font-size: 1.5rem; font-weight: 300; }
.lesson[open] summary::after { content: "–"; }
.lesson-body { padding: 0 40px 26px 121px; color: var(--muted); font-size: .88rem; }
.lesson-body p { margin: 0 0 13px; }
.lesson-body ol { margin: 0; padding-left: 20px; }
.lesson-body li + li { margin-top: 6px; }
.lesson-body strong { color: var(--text); }

.references {
  width: min(1240px, calc(100% - 40px));
  margin: 0 auto 90px;
  padding: 34px;
  border: 0;
  border-radius: 0;
  background: var(--surface);
}
.references h2 { margin-bottom: 8px; font: 700 2rem Montserrat, sans-serif; letter-spacing: -.045em; }
.references > p:not(.eyebrow) { color: var(--muted); font-size: .82rem; }
.references ul { display: flex; flex-wrap: wrap; gap: 8px 20px; margin: 20px 0 0; padding: 0; list-style: none; }
.references a { color: var(--text); font-size: .74rem; font-weight: 600; text-underline-offset: 3px; }

footer {
  min-height: 150px;
  padding: 42px max(20px, calc((100% - 1240px) / 2));
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 30px;
  color: var(--text);
  background: var(--paper);
  border-top: 1px solid var(--line);
}
footer p { margin: 0; color: var(--muted); font-size: .72rem; }

.sr-only {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

@media (max-width: 1050px) {
  .builder { width: min(960px, calc(100% - 40px)); padding: 0; }
  .builder-layout { grid-template-columns: 1fr; }
  .inspector { padding: 27px 26px 25px; }
  .inspector-sticky { position: static; display: grid; grid-template-columns: 1.1fr .9fr; gap: 26px; }
  .inspector-sticky > .eyebrow, .inspector-sticky > h2, .inspector-sticky > p, .connection-note { grid-column: 1; }
  .need-list { grid-column: 2; grid-row: 1 / span 5; }
}

@media (max-width: 760px) {
  .site-header { min-height: 72px; }
  nav { display: none; }
  .page-label { display: none; }
  .header-actions { gap: 0; }
  .intro { padding: 46px 0 30px; }
  .builder { width: calc(100% - 28px); padding: 0; border-radius: 0; }
  .workspace { padding: 18px; }
  .control-bar { grid-template-columns: 1fr; }
  .scene-frame { border-radius: 0; }
  .desk-scene { min-height: 300px; object-fit: cover; object-position: 52% center; }
  .device-label, .cable-label { display: none; }
  .scene-hint { display: none; }
  .change-notice { align-items: flex-start; flex-direction: column; }
  .setup-options { grid-template-columns: 1fr 1fr; }
  .setup-card { min-height: 118px; }
  .inspector-sticky { display: block; }
  .inspector { padding: 22px 18px; }
  .need-list { margin-top: 24px; }
  .learn { padding: 80px 0 65px; grid-template-columns: 1fr; gap: 30px; }
  .learn-intro { position: static; }
  .lesson summary { grid-template-columns: 80px 1fr 20px; }
  .lesson-body { padding-left: 96px; }
  .references { margin-bottom: 60px; padding: 24px; }
  .references ul { display: grid; }
  footer { align-items: flex-start; flex-direction: column; }
}

@media (max-width: 440px) {
  .site-header, .intro, .learn, .references { width: calc(100% - 28px); }
  h1 { font-size: 2.8rem; }
  .builder-head { align-items: flex-start; }
  .builder-head .text-button { margin-top: 5px; }
  .chooser-title { align-items: flex-start; }
  .setup-options { grid-template-columns: 1fr; }
  .setup-card { min-height: 100px; }
  .setup-card .setup-action { margin-bottom: 12px; }
  .signal-summary { align-items: flex-start; flex-direction: column; gap: 3px; }
  .lesson summary { grid-template-columns: 1fr 20px; gap: 6px; }
  .lesson summary span { grid-column: 1; }
  .lesson summary strong { grid-column: 1; }
  .lesson summary::after { grid-column: 2; grid-row: 1 / span 2; }
  .lesson-body { padding-left: 0; padding-right: 28px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}