@font-face {
  font-family: "IBM Plex Sans";
  src: url("/assets/fonts/ibm-plex-sans/IBMPlexSans-Regular.woff2")
    format("woff2");
  font-style: normal;
  font-weight: 400;
  font-display: swap;
}

@font-face {
  font-family: "IBM Plex Sans";
  src: url("/assets/fonts/ibm-plex-sans/IBMPlexSans-Medium.woff2")
    format("woff2");
  font-style: normal;
  font-weight: 500;
  font-display: swap;
}

@font-face {
  font-family: "IBM Plex Sans";
  src: url("/assets/fonts/ibm-plex-sans/IBMPlexSans-SemiBold.woff2")
    format("woff2");
  font-style: normal;
  font-weight: 600;
  font-display: swap;
}

:root {
  /* Layout */
  --page-width: 1200px;
  --text-width: 720px;
  --summary-width: 620px;

  /* Colour */
  --colour-black: #000000;
  --colour-text: #111111;
  --colour-muted: #5f5f5f;
  --colour-rule: #dddddd;
  --colour-rule-strong: #b8b8b8;
  --colour-background: #ffffff;
  --colour-background-subtle: #f5f5f3;

  /* Typography */
  --font-family-sans:
    "IBM Plex Sans", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;

  --font-size-body: 1rem;
  --font-size-small: 0.95rem;
  --font-size-eyebrow: 0.8rem;
  --font-size-lead: clamp(1.15rem, 2vw, 1.4rem);
  --font-size-heading: clamp(2.5rem, 7vw, 5rem);
  --font-size-section-heading: clamp(2rem, 5vw, 3rem);
  --font-size-card-heading: 1.4rem;

  --line-height-body: 1.6;
  --line-height-lead: 1.5;
  --line-height-heading: 0.98;
  --line-height-section-heading: 1.05;

  /* Spacing */
  --page-gutter: 24px;
  --page-gutter-mobile: 16px;
  --header-padding: 24px;
  --header-padding-mobile: 18px;
  --section-padding: 96px;
  --section-padding-mobile: 64px;
}

* {
  box-sizing: border-box;
}

html {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-body);
  color: var(--colour-text);
  background: var(--colour-background);
}

body {
  margin: 0;
  min-height: 100vh;
}

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

a {
  color: inherit;
}

:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  top: 0;
  left: var(--page-gutter);
  z-index: 100;
  padding: 12px 16px;
  color: var(--colour-background);
  background: var(--colour-text);
  font-weight: var(--font-weight-medium);
  transform: translateY(calc(-100% - 4px));
}

.skip-link:focus-visible {
  outline-color: var(--colour-text);
  transform: translateY(0);
}

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

.site-header__inner {
  width: min(var(--page-width), calc(100% - (2 * var(--page-gutter))));
  margin: 0 auto;
  padding: var(--header-padding) 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 48px;
}

.site-logo {
  display: inline-block;
  flex: 0 0 auto;
}

.site-logo img {
  width: 240px;
  height: auto;
}

.site-nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px 28px;
}

.site-nav a {
  padding: 3px 0;
  font-size: var(--font-size-small);
  font-weight: var(--font-weight-medium);
  line-height: 1.2;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  text-decoration: underline;
  text-underline-offset: 0.3em;
}

.site-nav [aria-current="page"] {
  font-weight: var(--font-weight-semibold);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 0.3em;
}

.site-main {
  width: min(var(--page-width), calc(100% - (2 * var(--page-gutter))));
  margin: 0 auto;
}

.intro {
  max-width: var(--text-width);
  padding: var(--section-padding) 0;
}

.intro--home {
  max-width: none;
}

.intro__eyebrow,
.site-section__eyebrow {
  font-weight: var(--font-weight-medium);
  text-transform: uppercase;
}

.intro__eyebrow {
  margin: 0 0 20px;
  font-size: var(--font-size-small);
  letter-spacing: 0.04em;
}

.intro h1 {
  margin: 0;
  font-size: var(--font-size-heading);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-heading);
  letter-spacing: -0.035em;
}

.intro__summary {
  max-width: var(--summary-width);
  margin: 32px 0 0;
  font-size: var(--font-size-lead);
  line-height: var(--line-height-lead);
}

.story-navigation {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin: 28px 0 0;
  font-size: var(--font-size-small);
}

.story-navigation a {
  font-weight: var(--font-weight-medium);
  text-underline-offset: 0.25em;
}

.story-navigation--footer {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--colour-rule);
}

.intro__body {
  max-width: var(--text-width);
  margin: 24px 0 0;
  font-size: 1.125rem;
  line-height: 1.65;
}

.intro__prose {
  margin-top: 24px;
}

.home-system-image {
  width: 60%;
  max-width: 100%;
  height: auto;
  margin-top: 48px;
}

.component-media {
  width: min(100%, 960px);
  margin: 0 0 var(--section-padding);
}

.component-media__video,
.component-media__poster {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  background: var(--colour-background-subtle);
}

.component-media__image {
  display: block;
  width: 100%;
  height: auto;
  background: var(--colour-background-subtle);
}

.component-media__poster {
  display: none;
  object-fit: cover;
}

.component-media figcaption {
  max-width: var(--text-width);
  margin-top: 12px;
  color: var(--colour-muted);
  font-size: var(--font-size-small);
}

.story-illustration-note {
  display: block;
  margin-top: 8px;
  font-style: italic;
}

.site-section {
  padding: var(--section-padding) 0;
  border-top: 1px solid var(--colour-rule);
}

.site-section__header {
  max-width: var(--text-width);
  margin-bottom: 32px;
}

.site-section__eyebrow {
  margin: 0 0 12px;
  font-size: var(--font-size-eyebrow);
  letter-spacing: 0.08em;
  line-height: 1.3;
}

.site-section h2 {
  margin: 0;
  font-size: var(--font-size-section-heading);
  font-weight: var(--font-weight-medium);
  letter-spacing: -0.025em;
  line-height: var(--line-height-section-heading);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

.feature-grid--single {
  grid-template-columns: minmax(0, var(--text-width));
}

.feature-card {
  display: flex;
  flex-direction: column;
  min-height: 256px;
  padding: 28px;
  border: 1px solid var(--colour-rule-strong);
}

.feature-card :is(h2, h3) {
  margin: 0 0 16px;
  font-size: var(--font-size-card-heading);
  font-weight: var(--font-weight-medium);
  line-height: 1.2;
}

.feature-card :is(h2, h3) a {
  text-decoration: none;
}

.feature-card :is(h2, h3) a:hover,
.feature-card :is(h2, h3) a:focus-visible {
  text-decoration: underline;
  text-underline-offset: 0.25em;
}

.feature-card p {
  margin: 0;
}

.feature-card__link {
  margin-top: auto;
  padding-top: 32px;
}

.feature-card__link a {
  font-weight: var(--font-weight-medium);
  text-underline-offset: 0.25em;
}

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

.prose p {
  margin: 0;
  font-size: 1.05rem;
  line-height: 1.7;
}

.prose p + p {
  margin-top: 20px;
}

.prose .component-media {
  margin: 32px 0;
}

.comparison-table {
  max-width: 100%;
  overflow-x: auto;
}

.comparison-table table {
  width: 100%;
  min-width: 760px;
  border-collapse: collapse;
  font-size: var(--font-size-small);
  line-height: 1.5;
}

.comparison-table caption {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.comparison-table :is(th, td) {
  width: 33.333%;
  padding: 18px;
  border: 1px solid var(--colour-rule-strong);
  text-align: left;
  vertical-align: top;
}

.comparison-table thead th {
  background: var(--colour-background-subtle);
  font-weight: var(--font-weight-semibold);
}

.comparison-table tbody th {
  font-weight: var(--font-weight-medium);
}

.qualification {
  margin-inline: calc(-1 * var(--page-gutter));
  padding-inline: var(--page-gutter);
  background: var(--colour-background-subtle);
  border-top-color: var(--colour-rule-strong);
}

.related-links {
  max-width: var(--text-width);
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  list-style: none;
}

.related-links a {
  font-weight: var(--font-weight-medium);
  text-underline-offset: 0.25em;
}

.site-footer {
  color: var(--colour-background);
  background: var(--colour-text);
}

.site-footer__inner {
  width: min(var(--page-width), calc(100% - (2 * var(--page-gutter))));
  margin: 0 auto;
  padding: 48px 0;
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 48px;
}

.site-footer__logo img {
  width: 200px;
  height: auto;
}

.site-footer__details {
  text-align: right;
  color: var(--colour-rule);
}

.site-footer__details p {
  margin: 0;
}

.site-footer__details p + p {
  margin-top: 8px;
}

.site-footer__details a {
  color: var(--colour-background);
  text-underline-offset: 0.2em;
}

@media (max-width: 48rem) {
  .site-header__inner,
  .site-main,
  .site-footer__inner {
    width: min(var(--page-width), calc(100% - (2 * var(--page-gutter-mobile))));
  }

  .site-header__inner {
    padding: var(--header-padding-mobile) 0;
    align-items: flex-start;
    flex-direction: column;
    gap: 20px;
  }

  .site-logo img {
    width: 190px;
  }

  .site-nav {
    width: 100%;
    gap: 12px 20px;
  }

  .intro,
  .site-section {
    padding: var(--section-padding-mobile) 0;
  }

  .component-media {
    margin-bottom: var(--section-padding-mobile);
  }

  .home-system-image {
    width: 100%;
  }

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

  .qualification {
    margin-inline: calc(-1 * var(--page-gutter-mobile));
    padding-inline: var(--page-gutter-mobile);
  }

  .feature-card {
    min-height: auto;
  }

  .site-footer__inner {
    padding: 40px 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 28px;
  }

  .site-footer__logo img {
    width: 180px;
  }

  .site-footer__details {
    text-align: left;
  }
}

@media (prefers-reduced-motion: reduce) {
  .component-media__video {
    display: none;
  }

  .component-media__poster {
    display: block;
  }
}