@font-face {
  font-family: "IBM Plex Sans";
  src: url("/guide/fonts/IBMPlexSansVar-Roman.woff2") format("woff2-variations");
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
}

@font-face {
  font-family: "IBM Plex Mono";
  src: url("/guide/fonts/IBMPlexMonoVar-Roman.woff2") format("woff2-variations");
  font-style: normal;
  font-weight: 100 700;
  font-display: swap;
}

:root {
  color-scheme: light;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  --content-wide: 1280px;
  --content-text: 720px;
  --page-pad: 40px;
  --paper: #f5f6f7;
  --surface: #fff;
  --ink: #111820;
  --muted: #52606d;
  --accent: #123b66;
  --signal: #8a5a00;
  --line: #cbd3da;
  --soft-fill: #f7df9b;
  --font-body: "IBM Plex Sans", "Noto Sans", Arial, sans-serif;
  --font-mono: "IBM Plex Mono", "Noto Sans Mono", monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

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

body {
  min-inline-size: 320px;
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 18px;
  line-height: 1.65;
}

img {
  display: block;
  block-size: auto;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

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

a:focus-visible,
button:focus-visible,
summary:focus-visible,
[tabindex="0"]:focus-visible {
  outline: 3px solid var(--signal);
  outline-offset: 3px;
}

button,
summary {
  font: inherit;
}

.skip-link {
  position: fixed;
  inset-block-start: 8px;
  inset-inline-start: 8px;
  z-index: 100;
  padding: 10px 14px;
  background: var(--ink);
  color: #fff;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: none;
}

.site-header,
.hero,
.chapter,
.ad-slot {
  inline-size: min(var(--content-wide), calc(100% - (var(--page-pad) * 2)));
  margin-inline: auto;
}

.site-header {
  min-block-size: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-block-start: 6px solid var(--accent);
  border-block-end: 1px solid var(--line);
}

.wordmark {
  min-block-size: 44px;
  display: inline-flex;
  align-items: center;
  color: var(--ink);
  font-size: 23px;
  font-weight: 780;
  letter-spacing: -0.035em;
  text-decoration: none;
}

.language-switch {
  display: flex;
  align-items: center;
  gap: 4px;
}

.language-switch button {
  min-inline-size: 46px;
  min-block-size: 46px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
}

.language-switch button[aria-pressed="true"] {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  text-decoration: underline 2px;
  text-underline-offset: 0.25em;
}

.hero {
  padding-block: 72px 82px;
  border-block-end: 1px solid var(--line);
}

.hero__copy {
  max-inline-size: 940px;
}

.hero__eyebrow {
  margin: 0 0 20px;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

h1,
h2 {
  margin-block-start: 0;
  text-wrap: balance;
}

h1 {
  max-inline-size: 920px;
  margin-block-end: 28px;
  font-size: clamp(40px, 4.5vw, 60px);
  font-weight: 760;
  letter-spacing: -0.045em;
  line-height: 1.04;
}

h2 {
  margin-block-end: 22px;
  font-size: clamp(28px, 3vw, 38px);
  font-weight: 720;
  letter-spacing: -0.03em;
  line-height: 1.12;
}

p {
  margin-block: 0 18px;
}

.hero__lead {
  max-inline-size: 760px;
  font-size: 21px;
  font-weight: 620;
  line-height: 1.52;
}

.hero__cta {
  margin-block-start: 30px;
}

.hero__cta a {
  min-block-size: 50px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 20px;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  text-decoration: none;
}

.guide-layout {
  inline-size: min(1456px, calc(100% - 48px));
  margin-inline: auto;
}

.toc--mobile {
  display: none;
}

.toc-holder {
  position: sticky;
  inset-block-start: 24px;
  align-self: start;
  margin-block-start: 72px;
  padding: 18px;
  border: 1px solid var(--line);
  background-color: #fbfcfd;
  background-image:
    linear-gradient(rgba(18, 59, 102, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(18, 59, 102, 0.07) 1px, transparent 1px);
  background-size: 22px 22px;
}

.toc__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc li + li {
  margin-block-start: 10px;
}

.toc a {
  min-block-size: 44px;
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  align-items: center;
  gap: 8px;
  padding: 6px 8px;
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  color: var(--ink);
  font-size: 14px;
  line-height: 1.35;
  text-decoration: none;
}

.toc a span {
  color: var(--signal);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
}

.toc a[aria-current="location"] {
  border-inline-start: 4px solid var(--accent);
  background: var(--surface);
  font-weight: 700;
}

.chapter {
  position: relative;
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 28px;
  padding-block: 78px;
  border-block-end: 1px solid var(--line);
}

.chapter__marker {
  color: var(--signal);
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  line-height: 1;
}

.chapter__marker::after {
  content: "";
  display: block;
  inline-size: 2px;
  block-size: 72px;
  margin-block-start: 16px;
  background: var(--signal);
}

.chapter__topics {
  min-inline-size: 0;
}

.topic {
  max-inline-size: 1060px;
}

.topic + .topic {
  margin-block-start: 72px;
}

.topic__copy {
  max-inline-size: var(--content-text);
}

.topic--paired {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 420px);
  align-items: start;
  gap: 48px;
}

.topic--paired .topic__copy {
  max-inline-size: 590px;
}

.topic--evidence-wide {
  display: block;
}

.topic--evidence-wide .topic__copy {
  max-inline-size: var(--content-text);
}

.topic--evidence-wide > .proof {
  margin-block-start: 28px;
}

.feature-list,
.checklist {
  margin: 22px 0 0;
  padding: 0;
}

.feature-list {
  list-style: none;
}

.feature-list li {
  position: relative;
  padding: 13px 0 13px 22px;
  border-block-start: 1px solid var(--line);
}

.feature-list li::before {
  content: "";
  position: absolute;
  inset-block-start: 20px;
  inset-inline-start: 0;
  inline-size: 5px;
  block-size: 18px;
  background: #e6a100;
}

.checklist {
  counter-reset: guide-check;
  list-style: none;
}

.checklist li {
  counter-increment: guide-check;
  position: relative;
  padding: 15px 0 15px 52px;
  border-block-start: 1px solid var(--line);
}

.checklist li::before {
  content: counter(guide-check, decimal-leading-zero);
  position: absolute;
  inset-block-start: 15px;
  inset-inline-start: 0;
  color: var(--signal);
  font: 700 14px/1.5 var(--font-mono);
}

.proof {
  min-inline-size: 0;
  margin: 0;
}

.proof__media {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: center;
  gap: 16px;
}

.proof__sheet {
  inline-size: fit-content;
  max-inline-size: 100%;
  overflow: hidden;
  justify-self: center;
  border: 1px solid var(--line);
  background: var(--surface);
}

.proof__sheet picture {
  display: block;
  max-inline-size: 100%;
}

.proof__sheet img {
  inline-size: auto;
  max-inline-size: 100%;
  margin-inline: auto;
  background: #fff;
}

.proof__label {
  min-block-size: 42px;
  display: flex;
  align-items: center;
  padding: 8px 11px;
  border-block-end: 1px solid var(--line);
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
  line-height: 1.35;
}

.proof[data-proof="reference-edge-dimensions"] .proof__item:first-child {
  flex: 0 0 294px;
  align-self: flex-start;
}

.proof[data-proof="reference-edge-dimensions"] .proof__item:not(:first-child) {
  flex: 0 0 152px;
}

.proof[data-proof="fronts"] .proof__item:last-child {
  inline-size: min(810px, 100%);
}

.proof[data-proof="drawing-views"] .proof__media {
  flex-direction: column;
  align-items: center;
}

.proof[data-proof="drawing-views"] .proof__item {
  flex: none;
}

.proof[data-proof="drawer-sheets"] .proof__item {
  inline-size: min(760px, 100%);
}

.ad-slot {
  min-block-size: 250px;
  display: grid;
  place-content: center;
  gap: 8px;
  margin-block: 0;
  padding: 24px;
  border-inline: 8px solid #e6a100;
  background: var(--surface);
  color: var(--muted);
  text-align: center;
}

.ad-slot__label {
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
}

.ad-slot small {
  font-size: 14px;
}

.back-to-top {
  display: none;
}

@media (min-width: 1100px) {
  body {
    --guide-gutter: max(24px, calc((100% - 1456px) / 2));
    background-color: var(--paper);
    background-image:
      linear-gradient(
        to right,
        transparent 0,
        transparent calc(var(--guide-gutter) + 210px),
        var(--paper) calc(var(--guide-gutter) + 288px)
      ),
      linear-gradient(rgba(18, 59, 102, 0.07) 1px, transparent 1px),
      linear-gradient(90deg, rgba(18, 59, 102, 0.07) 1px, transparent 1px);
    background-repeat: no-repeat, repeat, repeat;
    background-size: 100% 100%, 22px 22px, 22px 22px;
  }

  .guide-layout {
    display: grid;
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 38px;
  }

  .toc-holder {
    border-color: transparent;
    background: transparent;
  }

  .guide {
    min-inline-size: 0;
  }
}

@media (max-width: 1099px) {
  :root {
    --page-pad: 24px;
  }

  .guide-layout {
    inline-size: 100%;
  }

  .toc--desktop {
    display: none;
  }

  .toc--mobile {
    display: block;
  }

  .toc-holder {
    position: sticky;
    inset-block-start: 0;
    z-index: 20;
    inline-size: min(var(--content-wide), calc(100% - (var(--page-pad) * 2)));
    margin: 0 auto;
    padding: 10px 0;
    border: 0;
    border-block: 1px solid var(--line);
    background: color-mix(in srgb, var(--paper) 95%, transparent);
    backdrop-filter: blur(9px);
  }

  .toc--mobile summary {
    min-block-size: 44px;
    display: flex;
    align-items: center;
    padding-inline: 12px;
    color: var(--accent);
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
  }

  .toc--mobile nav {
    padding: 8px;
    border: 1px solid var(--line);
    background-color: #fbfcfd;
    background-image:
      linear-gradient(rgba(18, 59, 102, 0.07) 1px, transparent 1px),
      linear-gradient(90deg, rgba(18, 59, 102, 0.07) 1px, transparent 1px);
    background-size: 22px 22px;
  }

  .toc--mobile .toc__list {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 6px;
  }

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

  .toc--mobile a {
    grid-template-columns: 1fr;
    gap: 2px;
  }

  .chapter {
    grid-template-columns: 54px minmax(0, 1fr);
    gap: 22px;
    padding-block: 66px;
  }

  .topic--paired {
    grid-template-columns: minmax(0, 1fr);
  }

  .topic--paired .topic__copy {
    max-inline-size: var(--content-text);
  }

  .topic--paired > .proof {
    margin-block-start: 28px;
  }
}

@media (max-width: 767px) {
  :root {
    --page-pad: 16px;
  }

  body {
    font-size: 17px;
    line-height: 1.6;
  }

  .site-header {
    min-block-size: 66px;
  }

  .wordmark {
    font-size: 21px;
  }

  .hero {
    padding-block: 42px 52px;
  }

  h1 {
    margin-block-end: 22px;
    font-size: clamp(31px, 9.6vw, 38px);
    line-height: 1.07;
  }

  h2 {
    font-size: 28px;
  }

  .hero__lead {
    font-size: 18px;
  }

  .hero__cta a {
    inline-size: 100%;
  }

  .toc--mobile .toc__list {
    grid-template-columns: minmax(0, 1fr);
  }

  .toc--mobile a {
    grid-template-columns: 30px minmax(0, 1fr);
  }

  .chapter {
    display: block;
    padding-block: 54px;
  }

  .chapter__marker {
    margin-block-end: 26px;
  }

  .chapter__marker::after {
    inline-size: 64px;
    block-size: 2px;
    margin-block-start: 9px;
  }

  .topic + .topic {
    margin-block-start: 54px;
  }

  .proof__media {
    gap: 14px;
  }

  .proof__sheet {
    max-inline-size: 100%;
  }

  .proof__sheet img {
    inline-size: auto;
    max-inline-size: 100%;
  }

  .proof[data-proof="reference-edge-dimensions"] .proof__item:first-child {
    flex-basis: 100%;
  }

  .proof[data-proof="reference-edge-dimensions"] .proof__item:not(:first-child) {
    flex-basis: calc(50% - 7px);
    min-inline-size: 0;
  }

  .proof[data-proof="fronts"] .proof__item:last-child {
    inline-size: min(288px, 100%);
  }

  .proof[data-proof="drawer-sheets"] {
    inline-size: 100vw;
    margin-inline: calc(50% - 50vw);
  }

  .proof[data-proof="drawer-sheets"] .proof__item {
    inline-size: min(408px, calc(100vw - 16px));
    max-inline-size: calc(100vw - 16px);
  }

  .proof[data-proof="drawer-sheets"] .proof__sheet img {
    display: block;
    margin-inline: auto;
  }

  .chapter .topic:last-child .back-to-top {
    min-block-size: 44px;
    display: inline-flex;
    align-items: center;
    margin-block-start: 24px;
    font-size: 14px;
  }

  .ad-slot {
    min-block-size: 180px;
    inline-size: calc(100% - 32px);
  }
}

@media print {
  .site-header,
  .toc-holder,
  .ad-slot,
  .back-to-top {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
    font-size: 11pt;
  }

  .hero,
  .chapter {
    inline-size: 100%;
  }

  .chapter {
    display: block;
    break-inside: auto;
  }

  .topic,
  .proof__sheet {
    break-inside: avoid;
  }
}