@font-face {
  font-family: "Source Serif 4 Variable";
  src: url("https://echokin.fun/contralabs/assets/vEFI2_tTDB4M7-auWDN0ahZJW1gb8tc.woff2") format("woff2");
  font-display: swap;
  font-style: normal;
  font-weight: 200 900;
}

@font-face {
  font-family: "GT Standard L";
  src: url("https://echokin.fun/contralabs/assets/6U9zVlEligfePRtJbFpZy8V9jbY.woff2") format("woff2");
  font-display: swap;
  font-style: normal;
  font-weight: 400 700;
}

:root {
  --ink: oklch(0.27 0.018 281);
  --ink-soft: oklch(0.46 0.018 281);
  --muted: oklch(0.59 0.018 24);
  --paper: oklch(0.968 0.014 78);
  --paper-deep: oklch(0.938 0.024 78);
  --paper-raised: oklch(0.982 0.009 78);
  --rule: oklch(0.79 0.018 73);
  --purple: oklch(0.53 0.245 286);
  --purple-soft: oklch(0.91 0.05 291);
  --green: oklch(0.55 0.12 155);
  --green-soft: oklch(0.92 0.04 151);
  --amber: oklch(0.62 0.13 75);
  --amber-soft: oklch(0.93 0.045 78);
  --header-height: 64px;
  --sidebar-width: 286px;
  --toc-width: 220px;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  scroll-behavior: smooth;
  scroll-padding-top: 96px;
  background: var(--paper);
  color: var(--ink);
}

body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 20% 12%, color-mix(in oklch, var(--paper-raised) 92%, transparent) 0 0.6px, transparent 0.8px) 0 0 / 5px 5px,
    var(--paper);
  color: var(--ink);
  font-family: "GT Standard L", "Avenir Next", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  text-rendering: optimizeLegibility;
}

button,
input {
  font: inherit;
}

a {
  color: inherit;
}

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

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

::selection {
  color: var(--paper);
  background: var(--ink);
}

.skip-link {
  position: fixed;
  z-index: 200;
  top: 8px;
  left: 12px;
  padding: 8px 12px;
  border-radius: 6px;
  color: var(--paper);
  background: var(--ink);
  transform: translateY(-150%);
}

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

.topbar {
  position: fixed;
  z-index: 80;
  inset: 0 0 auto;
  display: flex;
  height: var(--header-height);
  align-items: center;
  border-bottom: 1px solid color-mix(in oklch, var(--rule) 74%, transparent);
  background: color-mix(in oklch, var(--paper) 96%, transparent);
}

.topbar__inner {
  display: flex;
  width: 100%;
  height: 100%;
  align-items: center;
  gap: 18px;
  padding: 0 24px;
}

.brand {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  gap: 9px;
  flex: none;
  text-decoration: none;
}

.brand__logo {
  width: 40px;
  height: 40px;
  object-fit: contain;
}

.brand__wordmark {
  display: inline-flex;
  align-items: baseline;
  gap: 4px;
  white-space: nowrap;
}

.brand__echo {
  font-family: "Source Serif 4 Variable", Georgia, serif;
  font-size: 22px;
  font-weight: 760;
  letter-spacing: -0.065em;
}

.brand__labs {
  font-size: 15px;
  font-weight: 650;
  letter-spacing: -0.04em;
}

.brand__divider {
  width: 1px;
  height: 22px;
  margin-left: 4px;
  background: var(--rule);
}

.brand__docs {
  font-size: 14px;
  font-weight: 650;
  letter-spacing: 0.01em;
}

.topbar__spacer {
  flex: 1;
}

.search-trigger {
  display: flex;
  width: min(330px, 31vw);
  min-height: 40px;
  align-items: center;
  gap: 10px;
  padding: 0 12px;
  border: 1px solid var(--rule);
  border-radius: 9px;
  color: var(--ink-soft);
  background: var(--paper-raised);
  cursor: pointer;
  transition: border-color 180ms ease, color 180ms ease, background-color 180ms ease;
}

.search-trigger:hover {
  border-color: color-mix(in oklch, var(--purple) 46%, var(--rule));
  color: var(--ink);
  background: color-mix(in oklch, var(--purple-soft) 28%, var(--paper-raised));
}

.search-trigger__label {
  overflow: hidden;
  flex: 1;
  text-align: left;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.language-switch {
  display: inline-flex;
  min-height: 38px;
  align-items: center;
  padding: 3px;
  border: 1px solid var(--rule);
  border-radius: 8px;
  background: var(--paper-raised);
}

.language-switch a {
  display: inline-flex;
  min-width: 38px;
  min-height: 30px;
  align-items: center;
  justify-content: center;
  padding: 0 8px;
  border-radius: 5px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  text-decoration: none;
}

.language-switch a:hover {
  color: var(--purple);
}

.language-switch a[aria-current="page"] {
  color: var(--ink);
  background: var(--paper-deep);
}

kbd {
  display: inline-flex;
  min-width: 25px;
  height: 23px;
  align-items: center;
  justify-content: center;
  padding: 0 6px;
  border: 1px solid var(--rule);
  border-radius: 5px;
  color: var(--muted);
  background: var(--paper);
  font-size: 12px;
  line-height: 1;
}

.topbar__link,
.topbar__app-link {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  padding: 0 14px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 650;
  text-decoration: none;
  white-space: nowrap;
}

.topbar__link:hover {
  color: var(--purple);
}

.topbar__app-link {
  border: 1px solid var(--ink);
  color: var(--paper);
  background: var(--ink);
  transition: background-color 180ms ease, border-color 180ms ease;
}

.topbar__app-link:hover {
  border-color: var(--purple);
  background: var(--purple);
}

.sidebar-toggle {
  display: none;
  width: 42px;
  height: 42px;
  place-items: center;
  padding: 0;
  border: 0;
  border-radius: 8px;
  background: transparent;
  cursor: pointer;
}

.docs-shell {
  display: grid;
  min-height: 100vh;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr) var(--toc-width);
  padding-top: var(--header-height);
}

.sidebar {
  position: fixed;
  z-index: 40;
  top: var(--header-height);
  bottom: 0;
  left: 0;
  width: var(--sidebar-width);
  overflow-y: auto;
  border-right: 1px solid var(--rule);
  background: color-mix(in oklch, var(--paper-deep) 88%, var(--paper));
}

.sidebar__inner {
  padding: 26px 22px 38px;
}

.sidebar__intro {
  padding: 0 8px 22px;
  border-bottom: 1px solid var(--rule);
}

.sidebar__eyebrow,
.article-eyebrow {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.sidebar__title {
  margin: 5px 0 9px;
  font-family: "Source Serif 4 Variable", Georgia, serif;
  font-size: 24px;
  font-weight: 520;
  letter-spacing: -0.035em;
  line-height: 1.2;
}

.nav-group {
  margin-top: 24px;
}

.nav-group__title {
  margin: 0 8px 8px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.nav-group__list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-link {
  display: block;
  min-height: 40px;
  padding: 8px 10px;
  border-radius: 7px;
  color: var(--ink-soft);
  font-size: 14px;
  font-weight: 520;
  line-height: 1.45;
  text-decoration: none;
  transition: color 160ms ease, background-color 160ms ease;
}

.nav-link:hover {
  color: var(--ink);
  background: color-mix(in oklch, var(--paper-raised) 70%, transparent);
}

.nav-link[aria-current="page"] {
  color: var(--purple);
  background: color-mix(in oklch, var(--purple-soft) 58%, var(--paper));
  font-weight: 680;
}

.sidebar__footer {
  display: flex;
  margin: 28px 8px 0;
  padding-top: 18px;
  border-top: 1px solid var(--rule);
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font-size: 12px;
}

.sidebar__footer a {
  color: var(--ink-soft);
  text-decoration: none;
}

.sidebar__footer a:hover {
  color: var(--purple);
}

.content-column {
  grid-column: 2;
  min-width: 0;
}

.article-wrap {
  width: min(100%, 820px);
  margin: 0 auto;
  padding: 54px 48px 96px;
}

.breadcrumbs {
  display: flex;
  margin-bottom: 22px;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 13px;
}

.breadcrumbs a {
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--purple);
}

.article-header {
  padding-bottom: 30px;
  border-bottom: 1px solid var(--rule);
}

.article-header h1 {
  max-width: 17ch;
  margin: 0;
  font-family: "Source Serif 4 Variable", Georgia, "Songti SC", serif;
  font-size: 46px;
  font-weight: 430;
  letter-spacing: -0.045em;
  line-height: 1.08;
  text-wrap: balance;
}

.home-plate {
  position: relative;
  min-height: 250px;
  margin: 26px 0 34px;
  overflow: hidden;
  border: 1px solid var(--rule);
  border-radius: 14px;
  background: var(--paper-deep);
}

.home-plate img {
  width: 100%;
  height: 280px;
  object-fit: cover;
  object-position: center 28%;
}

.home-plate__caption {
  position: absolute;
  inset: auto 18px 18px;
  display: inline-flex;
  width: max-content;
  max-width: calc(100% - 36px);
  min-height: 34px;
  align-items: center;
  padding: 0 12px;
  border-radius: 999px;
  color: var(--paper);
  background: color-mix(in oklch, var(--ink) 92%, transparent);
  font-size: 12px;
  font-weight: 650;
}

.article-body {
  padding-top: 22px;
  color: var(--ink);
}

.article-body > :first-child {
  margin-top: 0;
}

.article-body h2,
.article-body h3,
.article-body h4 {
  position: relative;
  scroll-margin-top: 94px;
  color: var(--ink);
}

.article-body h2 {
  margin: 52px 0 18px;
  font-family: "Source Serif 4 Variable", Georgia, "Songti SC", serif;
  font-size: 30px;
  font-weight: 540;
  letter-spacing: -0.035em;
  line-height: 1.2;
}

.article-body h3 {
  margin: 34px 0 12px;
  font-size: 20px;
  font-weight: 720;
  letter-spacing: -0.02em;
  line-height: 1.4;
}

.article-body h4 {
  margin: 28px 0 10px;
  font-size: 17px;
  font-weight: 720;
}

.heading-anchor {
  margin-left: 8px;
  color: var(--purple);
  font-family: "GT Standard L", system-ui, sans-serif;
  font-size: 0.55em;
  font-weight: 700;
  opacity: 0;
  text-decoration: none;
  transition: opacity 150ms ease;
}

h2:hover .heading-anchor,
h3:hover .heading-anchor,
.heading-anchor:focus-visible {
  opacity: 1;
}

.article-body p {
  max-width: 70ch;
  margin: 16px 0;
}

.article-body a {
  color: var(--purple);
  font-weight: 600;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.article-body strong {
  font-weight: 760;
}

.article-body ul,
.article-body ol {
  max-width: 70ch;
  margin: 16px 0;
  padding-left: 1.45em;
}

.article-body li {
  margin: 7px 0;
  padding-left: 0.25em;
}

.article-body li::marker {
  color: var(--purple);
  font-weight: 700;
}

.callout {
  max-width: 70ch;
  margin: 24px 0;
  padding: 18px 20px;
  border: 1px solid color-mix(in oklch, var(--purple) 24%, var(--rule));
  border-radius: 10px;
  background: color-mix(in oklch, var(--purple-soft) 46%, var(--paper));
}

.callout p {
  margin: 0;
}

code {
  padding: 0.14em 0.38em;
  border: 1px solid color-mix(in oklch, var(--rule) 80%, transparent);
  border-radius: 5px;
  color: color-mix(in oklch, var(--purple) 88%, var(--ink));
  background: color-mix(in oklch, var(--paper-deep) 74%, var(--paper));
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 0.88em;
}

pre {
  max-width: 100%;
  margin: 22px 0;
  overflow-x: auto;
  padding: 18px 20px;
  border: 1px solid color-mix(in oklch, var(--ink) 18%, var(--rule));
  border-radius: 10px;
  color: var(--paper);
  background: var(--ink);
  line-height: 1.65;
}

pre code {
  padding: 0;
  border: 0;
  color: inherit;
  background: transparent;
  font-size: 13px;
}

.table-wrap {
  width: 100%;
  margin: 24px 0;
  overflow-x: auto;
  border: 1px solid var(--rule);
  border-radius: 10px;
  background: color-mix(in oklch, var(--paper-raised) 72%, transparent);
}

table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-size: 14px;
  line-height: 1.55;
}

th,
td {
  padding: 13px 15px;
  border-bottom: 1px solid var(--rule);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--ink);
  background: var(--paper-deep);
  font-size: 13px;
  font-weight: 760;
}

tr:last-child td {
  border-bottom: 0;
}

.page-nav {
  display: grid;
  margin-top: 64px;
  padding-top: 22px;
  border-top: 1px solid var(--rule);
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.page-nav__link {
  display: flex;
  min-height: 90px;
  flex-direction: column;
  justify-content: center;
  padding: 15px 18px;
  border: 1px solid var(--rule);
  border-radius: 10px;
  text-decoration: none;
  transition: border-color 160ms ease, background-color 160ms ease;
}

.page-nav__link:hover {
  border-color: color-mix(in oklch, var(--purple) 46%, var(--rule));
  background: color-mix(in oklch, var(--purple-soft) 28%, transparent);
}

.page-nav__link--next {
  align-items: flex-end;
  text-align: right;
}

.page-nav__label {
  color: var(--muted);
  font-size: 12px;
  font-weight: 650;
}

.page-nav__title {
  margin-top: 3px;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.35;
}

.toc {
  position: fixed;
  top: var(--header-height);
  right: 0;
  bottom: 0;
  width: var(--toc-width);
  padding: 47px 22px;
  overflow-y: auto;
}

.toc__title {
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 760;
}

.toc__list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc__link {
  display: block;
  padding: 5px 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.4;
  text-decoration: none;
  transition: color 150ms ease;
}

.toc__link:hover,
.toc__link[aria-current="true"] {
  color: var(--purple);
}

.toc__link--sub {
  padding-left: 13px;
  font-size: 12px;
}

.search-dialog {
  width: min(680px, calc(100vw - 32px));
  max-height: min(720px, calc(100vh - 56px));
  padding: 0;
  overflow: hidden;
  border: 1px solid var(--rule);
  border-radius: 14px;
  color: var(--ink);
  background: var(--paper-raised);
  box-shadow: 0 24px 70px color-mix(in oklch, var(--ink) 22%, transparent);
}

.search-dialog::backdrop {
  background: color-mix(in oklch, var(--ink) 46%, transparent);
}

.search-form {
  display: flex;
  height: 62px;
  align-items: center;
  gap: 12px;
  padding: 0 18px;
  border-bottom: 1px solid var(--rule);
}

.search-input {
  min-width: 0;
  flex: 1;
  border: 0;
  outline: 0;
  color: var(--ink);
  background: transparent;
  font-size: 17px;
}

.search-input::placeholder {
  color: var(--muted);
}

.search-results {
  max-height: min(570px, calc(100vh - 180px));
  margin: 0;
  padding: 10px;
  overflow-y: auto;
  list-style: none;
}

.search-result {
  display: block;
  padding: 12px 13px;
  border-radius: 8px;
  text-decoration: none;
}

.search-result:hover,
.search-result:focus-visible {
  background: var(--paper-deep);
}

.search-result__group {
  color: var(--muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.search-result__title {
  display: block;
  margin-top: 2px;
  font-weight: 720;
}

.search-result__excerpt {
  display: block;
  margin-top: 3px;
  overflow: hidden;
  color: var(--ink-soft);
  font-size: 13px;
  line-height: 1.45;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.search-empty {
  display: grid;
  min-height: 220px;
  place-items: center;
  padding: 30px;
  color: var(--muted);
  text-align: center;
}

.sidebar-backdrop {
  display: none;
}

.loading-shell {
  width: min(760px, calc(100% - 48px));
  margin: 0 auto;
  padding-top: 150px;
}

.topbar__brand-skeleton,
.loading-line {
  border-radius: 6px;
  background: var(--paper-deep);
  animation: pulse 1.4s ease-in-out infinite alternate;
}

.topbar__brand-skeleton {
  width: 170px;
  height: 32px;
  margin-left: 24px;
}

.loading-line {
  width: 100%;
  height: 14px;
  margin-top: 15px;
}

.loading-line--title {
  width: 62%;
  height: 46px;
  margin-bottom: 34px;
}

.loading-line--short {
  width: 72%;
}

@keyframes pulse {
  to { opacity: 0.48; }
}

@media (max-width: 1180px) {
  .topbar__inner {
    gap: 12px;
    padding-inline: 20px;
  }

  .search-trigger {
    width: min(290px, 28vw);
  }

  .topbar__link {
    display: none;
  }

  .docs-shell {
    grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  }

  .toc {
    display: none;
  }
}

@media (max-width: 900px) {
  .topbar__inner {
    gap: 9px;
    padding: 0 14px;
  }

  .sidebar-toggle {
    display: grid;
    flex: none;
  }

  .brand__labs,
  .brand__divider,
  .brand__docs,
  .search-trigger kbd {
    display: none;
  }

  .brand__logo {
    width: 38px;
    height: 38px;
  }

  .brand__echo {
    font-size: 21px;
  }

  .search-trigger {
    width: 44px;
    min-height: 42px;
    justify-content: center;
    padding: 0;
    border-color: transparent;
    background: transparent;
  }

  .search-trigger__label {
    display: none;
  }

  .language-switch {
    min-height: 42px;
    padding: 0;
    border-color: transparent;
    background: transparent;
  }

  .language-switch a {
    min-width: 42px;
    min-height: 42px;
    padding: 0 5px;
  }

  .language-switch a[aria-current="page"] {
    display: none;
  }

  .topbar__app-link {
    min-height: 38px;
    padding: 0 13px;
    font-size: 13px;
  }

  .docs-shell {
    display: block;
  }

  .sidebar {
    z-index: 70;
    top: var(--header-height);
    width: min(330px, calc(100vw - 44px));
    transform: translateX(-104%);
    transition: transform 220ms cubic-bezier(0.22, 1, 0.36, 1);
    box-shadow: 18px 0 44px color-mix(in oklch, var(--ink) 12%, transparent);
  }

  body[data-nav-open="true"] {
    overflow: hidden;
  }

  body[data-nav-open="true"] .sidebar {
    transform: translateX(0);
  }

  .sidebar-backdrop {
    position: fixed;
    z-index: 60;
    inset: var(--header-height) 0 0;
    display: block;
    border: 0;
    background: color-mix(in oklch, var(--ink) 38%, transparent);
    cursor: pointer;
    opacity: 0;
    pointer-events: none;
    transition: opacity 180ms ease;
  }

  body[data-nav-open="true"] .sidebar-backdrop {
    opacity: 1;
    pointer-events: auto;
  }

  .article-wrap {
    width: min(100%, 760px);
    padding: 38px 26px 74px;
  }
}

@media (max-width: 560px) {
  body {
    font-size: 15px;
  }

  .topbar__inner {
    padding: 0 10px;
  }

  .brand {
    gap: 5px;
  }

  .topbar__spacer {
    display: none;
  }

  .search-trigger {
    margin-left: auto;
  }

  .article-wrap {
    padding: 30px 19px 64px;
  }

  .breadcrumbs {
    margin-bottom: 17px;
  }

  .article-header {
    padding-bottom: 24px;
  }

  .article-header h1 {
    font-size: 37px;
  }

  .article-body h2 {
    margin-top: 42px;
    font-size: 27px;
  }

  .article-body h3 {
    font-size: 19px;
  }

  .callout {
    padding: 16px;
  }

  .home-plate img {
    height: 230px;
  }

  .page-nav {
    grid-template-columns: 1fr;
  }

  .page-nav__link--next {
    align-items: flex-start;
    text-align: left;
  }
}

@media (max-width: 430px) {
  .brand__wordmark {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}