/* Colours come from Open Color, the palette the diagrams themselves are drawn in. */
:root {
  --ink: #1e1e1e;
  --muted: #495057;
  --page: #ffffff;
  --well: #f8f9fa;
  --frame: #868e96;
  --hairline: #dee2e6;
  --inline-code: #f1f3f5;
  --link: #1864ab;
  --focus: #1971c2;

  --client: #e9ecef;
  --service: #a5d8ff;
  --datastore: #b2f2bb;
  --queue: #ffec99;
  --cache: #ffd8a8;

  --sans: Seravek, "Gill Sans Nova", Ubuntu, Calibri, "DejaVu Sans", source-sans-pro, sans-serif;
  --mono: ui-monospace, "Cascadia Code", "Source Code Pro", Menlo, Consolas, "DejaVu Sans Mono", monospace;

  --s1: 0.25rem;
  --s2: 0.5rem;
  --s3: 0.75rem;
  --s4: 1rem;
  --s5: 1.5rem;
  --s6: 2rem;
  --s7: 3rem;
  --s8: 4rem;
  --s9: 6rem;

  --wide: 75rem;
  --measure: 42rem;
  --gutter: clamp(1rem, 4vw, 2.5rem);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

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

/* Type */

h1,
h2,
h3 {
  margin: 0;
  font-weight: 700;
  text-wrap: balance;
}

h1 {
  font-size: clamp(2.25rem, 1.4rem + 3.6vw, 4.25rem);
  line-height: 1.04;
  letter-spacing: -0.025em;
}

h2 {
  font-size: clamp(1.5rem, 1.2rem + 1vw, 1.875rem);
  line-height: 1.2;
  letter-spacing: -0.012em;
  margin-top: var(--s8);
  margin-bottom: var(--s4);
  scroll-margin-top: var(--s5);
}

h3 {
  font-size: 1.1875rem;
  line-height: 1.3;
  margin-top: var(--s6);
  margin-bottom: var(--s2);
  scroll-margin-top: var(--s5);
}

p,
ul,
ol,
dl {
  margin: 0 0 var(--s4);
}

li + li {
  margin-top: var(--s2);
}

a {
  color: var(--link);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  text-decoration-thickness: 2px;
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 2px;
}

code,
pre,
kbd {
  font-family: var(--mono);
}

:not(pre) > code {
  font-size: 0.875em;
  background: var(--inline-code);
  padding: 0.1em 0.32em;
  border-radius: 3px;
  overflow-wrap: anywhere;
}

.lede {
  font-size: clamp(1.125rem, 1.05rem + 0.4vw, 1.3125rem);
  line-height: 1.5;
  color: var(--ink);
  max-width: 38rem;
}

.muted {
  color: var(--muted);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

/* Shell */

.skip {
  position: absolute;
  left: var(--s4);
  top: -4rem;
  padding: var(--s2) var(--s4);
  background: var(--ink);
  color: #fff;
  z-index: 10;
}

.skip:focus {
  top: var(--s4);
}

.wrap {
  max-width: var(--wide);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.site-header {
  border-bottom: 1px solid var(--hairline);
}

.site-header .wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--s2) var(--s6);
  padding-block: var(--s4);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  color: var(--ink);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  text-decoration: none;
}

.brand img {
  width: 1.5rem;
  height: 1.5rem;
}

.site-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s1) var(--s5);
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav li + li {
  margin-top: 0;
}

.site-nav a {
  display: inline-block;
  padding-block: var(--s2);
  color: var(--ink);
  text-decoration: none;
}

.site-nav a:hover {
  text-decoration: underline;
  text-decoration-thickness: 1px;
}

@media (max-width: 40rem) {
  .site-header .wrap {
    padding-block: var(--s3);
  }

  .site-nav ul {
    gap: 0 var(--s4);
  }

  .site-nav a {
    padding-block: var(--s1);
  }
}

/* The current page is marked the way a highlighter would mark it, in the service fill. */
.site-nav a[aria-current="page"] {
  text-decoration: underline;
  text-decoration-color: var(--service);
  text-decoration-thickness: 0.4em;
  text-underline-offset: -0.12em;
  text-decoration-skip-ink: none;
}

main {
  display: block;
  padding-bottom: var(--s9);
}

.site-footer {
  border-top: 1px solid var(--hairline);
  color: var(--muted);
  font-size: 0.9375rem;
}

.site-footer .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--s4) var(--s6);
  padding-block: var(--s6) var(--s7);
}

.site-footer p {
  margin: 0;
  max-width: 32rem;
}

.site-footer ul {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s2) var(--s5);
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-footer li + li {
  margin-top: 0;
}

.site-footer a {
  color: var(--muted);
}

/* Code frames are drawn like the diagrams' group boxes: grey well, square corners, label top left. */

.frame {
  position: relative;
  margin: var(--s5) 0;
  background: var(--well);
  border: 1px solid var(--frame);
  min-width: 0;
}

.frame figcaption,
.frame .frame-label {
  display: block;
  padding: var(--s3) var(--s4) 0;
  color: var(--muted);
  font-size: 0.875rem;
}

.frame pre {
  margin: 0;
  padding: var(--s3) var(--s4) var(--s4);
  overflow-x: auto;
  font-size: 0.8125rem;
  line-height: 1.6;
  tab-size: 2;
}

/* Tool output is read as sentences, so it wraps instead of scrolling. */
.frame pre.output {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.frame pre:focus-visible {
  outline-offset: -3px;
}

.frame .copy {
  position: absolute;
  top: var(--s2);
  right: var(--s2);
  min-width: 4.5rem;
  min-height: 2.25rem;
  padding: 0 var(--s3);
  font: inherit;
  font-size: 0.875rem;
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--frame);
  border-radius: 4px;
  cursor: pointer;
}

.frame .copy:hover {
  background: var(--client);
}

.frame .copy[data-state="copied"] {
  background: var(--datastore);
}

/* A frame with no caption still reserves the button's corner. */
.frame:not(:has(figcaption)) pre {
  padding-top: var(--s4);
  padding-right: 6rem;
}

/* Renders sit on the white page as they would on an Excalidraw canvas; a hairline marks the sheet. */

.render {
  margin: var(--s6) 0;
  min-width: 0;
}

.render .sheet {
  border: 1px solid var(--hairline);
  background: #fff;
  overflow-x: auto;
}

.render figcaption {
  margin-top: var(--s2);
  color: var(--muted);
  font-size: 0.9375rem;
}

/* On a phone a full diagram scaled to the screen drops its labels below reading size, so detail frames scroll instead. */
.narrow-only {
  display: none;
}

/* A wide diagram scaled to the column drops its labels below reading size on any screen, so it always scrolls. */
.render.wide img {
  width: 100rem;
  max-width: none;
}

@media (max-width: 40rem) {
  .narrow-only {
    display: inline;
  }

  .render.scrolls img {
    width: 40rem;
    max-width: none;
  }
}

/* Index */

.hero {
  padding-top: clamp(var(--s7), 8vw, var(--s9));
}

.hero-head {
  display: grid;
  gap: var(--s5) var(--s7);
  align-items: end;
}

.hero h1 {
  max-width: 14ch;
}

.hero .lede {
  margin: 0;
}

@media (min-width: 60rem) {
  .hero-head {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }
}

.hero .render {
  margin-top: var(--s7);
}

.hero .render .sheet {
  border: 0;
  border-block: 1px solid var(--hairline);
}

/* On a phone the overview runs edge to edge, since every pixel of width is label size. */
@media (max-width: 40rem) {
  .hero .render .sheet {
    margin-inline: calc(var(--gutter) * -1);
  }
}

.source {
  display: grid;
  gap: var(--s4) var(--s6);
  align-items: start;
}

.source > * {
  min-width: 0;
}

.source > :first-child .frame {
  margin: 0;
}

.source h2:first-child,
.aside h2:first-child {
  margin-top: 0;
}

@media (min-width: 60rem) {
  .source {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
  }
}

.properties {
  display: grid;
  gap: var(--s5) var(--s6);
  margin: var(--s5) 0 0;
}

.properties div {
  min-width: 0;
}

.properties dt {
  font-weight: 700;
  font-size: 1.125rem;
  line-height: 1.3;
  margin-bottom: var(--s2);
}

.properties dd {
  margin: 0;
  color: var(--ink);
}

@media (min-width: 44rem) {
  .properties {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 68rem) {
  .properties {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.prose {
  max-width: var(--measure);
}

.next {
  display: grid;
  gap: var(--s4) var(--s6);
  margin: var(--s5) 0 0;
  padding: 0;
  list-style: none;
}

.next li + li {
  margin-top: 0;
}

.next a {
  font-weight: 700;
  font-size: 1.125rem;
}

.next p {
  margin: var(--s1) 0 0;
  color: var(--muted);
}

@media (min-width: 44rem) {
  .next {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 68rem) {
  .next {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* Inner pages */

.page-head {
  padding-top: clamp(var(--s6), 6vw, var(--s8));
  max-width: var(--measure);
}

.page-head h1 {
  font-size: clamp(2.125rem, 1.5rem + 2.4vw, 3.25rem);
  margin-bottom: var(--s4);
}

.doc {
  display: grid;
  gap: 0 var(--s8);
}

.doc > * {
  min-width: 0;
}

.doc-body > * {
  max-width: var(--measure);
}

.toc {
  margin-top: var(--s6);
  font-size: 0.9375rem;
}

.toc h2 {
  margin: 0 0 var(--s2);
  font-size: 0.9375rem;
  letter-spacing: 0;
  color: var(--muted);
}

.toc ol,
.toc ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc li + li {
  margin-top: var(--s1);
}

.toc a {
  display: inline-block;
  padding-block: 0.15rem;
  color: var(--ink);
  text-decoration: none;
}

.toc a:hover {
  text-decoration: underline;
}

@media (max-width: 63.99rem) {
  .toc ol,
  .toc ul {
    display: flex;
    flex-wrap: wrap;
    gap: 0 var(--s4);
  }

  .toc li + li {
    margin-top: 0;
  }

  .toc a {
    color: var(--link);
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 0.18em;
  }
}

@media (min-width: 64rem) {
  .doc {
    grid-template-columns: 12rem minmax(0, 1fr);
  }

  .toc {
    position: sticky;
    top: var(--s5);
    align-self: start;
    margin-top: var(--s8);
  }
}

/* Diagrams inside the doc column may run past the reading measure. */
.doc-body > .render {
  max-width: none;
}

.steps > li > * {
  max-width: var(--measure);
}

.steps {
  counter-reset: step;
  padding: 0;
  list-style: none;
}

.steps > li {
  counter-increment: step;
}

.steps h2::before {
  content: counter(step);
  display: inline-grid;
  place-items: center;
  width: 1.6em;
  height: 1.6em;
  margin-right: var(--s3);
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--client);
  font-size: 0.8em;
  vertical-align: 0.1em;
}

.note {
  margin: var(--s5) 0;
  padding: var(--s3) var(--s4);
  border-left: 4px solid var(--cache);
  background: var(--well);
}

.note p:last-child {
  margin-bottom: 0;
}

/* Tables */

.table-scroll {
  overflow-x: auto;
  margin: var(--s5) 0;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 1rem;
}

th,
td {
  text-align: left;
  vertical-align: top;
  padding: var(--s3) var(--s4) var(--s3) 0;
  border-bottom: 1px solid var(--hairline);
}

th {
  font-weight: 700;
  border-bottom-color: var(--frame);
}

td:first-child,
th:first-child {
  white-space: nowrap;
}

/* Kind swatches: the shape, fill and border each kind gets in a diagram. */

.swatch {
  display: inline-block;
  width: 3rem;
  height: 1.75rem;
  margin-right: var(--s3);
  vertical-align: middle;
  border: 2px solid var(--ink);
}

.swatch.client {
  background: var(--client);
  border-radius: 50%;
}

.swatch.service {
  background: var(--service);
  border-radius: 8px;
}

.swatch.datastore {
  background: var(--datastore);
}

.swatch.queue {
  background: repeating-linear-gradient(-45deg, var(--queue) 0 2px, transparent 2px 6px);
}

.swatch.cache {
  background: var(--cache);
}

.swatch.external {
  border-style: dashed;
  border-radius: 8px;
}

/* Examples */

.example + .example {
  margin-top: var(--s9);
}

.example h2 {
  margin-top: var(--s8);
}

.example-body {
  display: grid;
  gap: var(--s4) var(--s7);
  align-items: start;
}

.example-body > * {
  min-width: 0;
}

.example-body .frame {
  margin: 0;
}

@media (min-width: 60rem) {
  .example-body {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
  }
}

.downloads {
  padding: 0;
  list-style: none;
}

.downloads li + li {
  margin-top: var(--s1);
}

.downloads a {
  display: inline-block;
  padding-block: var(--s1);
}

.downloads span {
  color: var(--muted);
}

blockquote {
  margin: var(--s5) 0;
  padding: 0 0 0 var(--s4);
  border-left: 4px solid var(--service);
}

.not-found {
  padding-top: var(--s9);
  max-width: var(--measure);
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}