:root {
  color-scheme: light dark;
  --ink: #111111;
  --muted: #333333;
  --paper: #ffffff;
  --deep: #000000;
  --link: #0000ff;
  --line: #333333;
  --radius: 4px;
  --shadow: 0 2px 12px rgb(0 0 0 / 8%);
  --gap: clamp(4rem, 8vw, 8rem);
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.6;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--link);
  text-underline-offset: 0.2em;
  text-decoration-thickness: 2px;
}

a:hover {
  text-decoration-thickness: 4px;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
summary:focus-visible {
  outline: 4px solid var(--link);
  outline-offset: 3px;
}

.skip {
  position: absolute;
  z-index: 100;
  top: 0.5rem;
  left: 0.5rem;
  min-height: 44px;
  padding: 0.55rem 0.8rem;
  border: 2px solid var(--link);
  background: var(--paper);
  color: var(--ink);
  transform: translateY(-160%);
}

.skip:focus {
  transform: translateY(0);
}

.wrap {
  width: min(1280px, 100%);
  margin-inline: auto;
  padding-inline: 1.5rem;
}

.site-head {
  border-bottom: 1px solid var(--line);
  background: var(--paper);
}

.head-in {
  display: grid;
  grid-template-columns: minmax(12rem, 0.65fr) minmax(0, 1.35fr);
  gap: 1.5rem;
  align-items: center;
  min-height: 96px;
}

.brand {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--ink);
  font-weight: 700;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand-mark {
  width: 24px;
  height: 24px;
  margin-right: 0.65rem;
  border: 4px solid var(--link);
  border-radius: 50%;
  box-shadow: inset 0 0 0 3px var(--paper);
  background: var(--link);
}

.topic-nav ul,
.foot-nav,
.plain-list,
.check-list,
.path-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.topic-nav ul {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.5rem 1rem;
}

.topic-nav li {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.topic-nav span,
.eyebrow,
.label,
.note-label,
.source-label {
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.topic-nav span {
  color: var(--muted);
  font-size: 0.75rem;
}

.topic-nav a,
.foot-nav a,
.next,
.btn,
.card-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.45rem 0.2rem;
  font-weight: 600;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(20rem, 0.95fr);
  gap: clamp(2rem, 6vw, 6rem);
  align-items: center;
  min-height: min(780px, calc(100vh - 96px));
  padding-block: clamp(3.5rem, 7vw, 7rem);
}

.hero-copy,
.prose {
  max-width: 72ch;
}

.hero-art {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) * 2);
  box-shadow: var(--shadow);
  background: #ffffff;
  transition: transform 300ms ease;
}

.hero-art:hover {
  transform: scale(1.03);
}

.eyebrow {
  display: inline-block;
  margin: 0 0 1rem;
  padding: 0.35rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

h1,
h2,
h3 {
  max-width: 28ch;
  margin-top: 0;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.035em;
}

h1 {
  margin-bottom: 1.5rem;
  font-size: clamp(2.5rem, 5vw, 4rem);
}

h2 {
  margin-bottom: 1.25rem;
  font-size: 1.5rem;
}

h3 {
  margin-bottom: 0.75rem;
  font-size: 1.15rem;
}

p,
li,
label,
input,
textarea,
button,
summary,
footer a,
footer p {
  font-size: 1rem;
}

p {
  max-width: 72ch;
  margin-top: 0;
  margin-bottom: 1rem;
}

.lede {
  max-width: 58ch;
  font-size: 1.2rem;
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 2rem;
}

.tag {
  padding: 0.35rem 0.6rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--mono);
  font-size: 0.875rem;
}

.section {
  padding-block: var(--gap);
  border-top: 1px solid var(--line);
}

.split,
.zig,
.cards,
.fields {
  display: grid;
  gap: 1.5rem;
}

.split,
.zig {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: start;
}

.zig:nth-child(even) .zig-copy {
  order: 2;
}

.cards {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.fields {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.card,
.fact,
.note-box,
.source,
.field {
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) * 2);
  box-shadow: var(--shadow);
  background: var(--paper);
}

.card,
.fact,
.field {
  padding: 1.5rem;
}

.card p:last-child,
.fact p:last-child {
  margin-bottom: 0;
}

.fact {
  border-left: 8px solid var(--link);
}

.card-link {
  margin-top: 0.5rem;
}

.check-list {
  display: grid;
  gap: 0.75rem;
}

.check-list label {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 0.75rem;
  align-items: start;
  min-height: 44px;
  padding: 0.6rem;
  border-bottom: 1px solid var(--line);
}

input[type="checkbox"] {
  width: 40px;
  height: 40px;
  margin: 0;
  accent-color: var(--link);
}

input[type="text"],
input[type="number"],
textarea {
  width: 100%;
  min-height: 48px;
  margin-top: 0.4rem;
  padding: 0.8rem;
  border: 2px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.5;
}

textarea {
  min-height: 180px;
  resize: vertical;
}

.note-box {
  padding: 1.5rem;
}

.note-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-top: 1rem;
}

.btn {
  justify-content: center;
  min-width: 120px;
  padding: 0.65rem 1rem;
  border: 2px solid var(--link);
  border-radius: 0.5rem;
  background: var(--link);
  color: #ffffff;
  font: 600 1rem/1.2 var(--sans);
  cursor: pointer;
}

.btn.alt {
  background: var(--paper);
  color: var(--link);
}

.status {
  margin: 0;
  font-family: var(--mono);
  font-size: 0.875rem;
}

.source-stack {
  display: grid;
  gap: 1rem;
}

.source {
  overflow: hidden;
}

.source summary {
  min-height: 44px;
  padding: 1rem 1.25rem;
  font-weight: 600;
  cursor: pointer;
}

.source-body {
  padding: 0 1.25rem 1.25rem;
}

.source-body a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.mono {
  font-family: var(--mono);
  font-size: 0.95em;
}

.next-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 2rem;
  border-top: 1px solid var(--line);
}

.site-foot {
  padding-block: 3rem;
  border-top: 1px solid var(--line);
  background: var(--deep);
  color: #ffffff;
}

.site-foot a {
  color: #ffffff;
  text-decoration-color: var(--link);
}

.foot-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1rem;
  margin-bottom: 1.5rem;
}

.site-foot p {
  color: #ffffff;
}

@media (max-width: 900px) {
  .head-in {
    grid-template-columns: 1fr;
    gap: 0;
    padding-block: 1rem;
  }

  .topic-nav ul {
    justify-content: flex-start;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: 0;
  }

  .hero-art {
    max-width: 42rem;
  }

  .cards {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 767px) {
  .wrap {
    padding-inline: 1rem;
  }

  .topic-nav li {
    width: 100%;
  }

  .topic-nav span {
    width: 5rem;
  }

  .split,
  .zig,
  .cards,
  .fields {
    grid-template-columns: 1fr;
  }

  .zig:nth-child(even) .zig-copy {
    order: initial;
  }

  h1 {
    font-size: 2.5rem;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #ffffff;
    --muted: #ffffff;
    --paper: #000000;
    --line: #ffffff;
    --shadow: 0 2px 12px rgb(255 255 255 / 12%);
  }

  a {
    color: #ffffff;
    text-decoration-color: var(--link);
  }

  .brand-mark {
    box-shadow: inset 0 0 0 3px #000000;
  }

  .hero-art {
    background: #333333;
  }

  .card,
  .fact,
  .note-box,
  .source,
  .field {
    background: #333333;
  }

  .btn.alt {
    background: #000000;
    color: #ffffff;
  }

  a:focus-visible,
  button:focus-visible,
  input:focus-visible,
  textarea:focus-visible,
  summary:focus-visible {
    outline-color: #ffffff;
    box-shadow: 0 0 0 6px var(--link);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}