@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Instrument+Sans:wght@500;600;700&family=IBM+Plex+Mono:wght@400;500&display=swap');

:root {
  --ink: #172a36;
  --muted: #506571;
  --accent: #006052;
  --line: #d9e2e2;
  --paper: #f3f6f6;
  --wash: #f6f9f8;
  --heading: 'Instrument Sans', system-ui, sans-serif;
  --mono: 'IBM Plex Mono', monospace;
  color: var(--ink);
  background: var(--paper);
  font: 1rem/1.7 'DM Sans', system-ui, sans-serif;
  scroll-padding-top: 6rem;
}
* { box-sizing: border-box; }
body { margin: 0; }
a { color: var(--accent); text-underline-offset: .24em; }
:focus-visible { outline: 3px solid #007c68; outline-offset: 3px; }
.skip { position: fixed; top: .75rem; left: 1rem; z-index: 5; padding: .5rem 1rem; background: white; transform: translateY(-200%); }
.skip:focus { transform: none; }
.layout { display: grid; grid-template-columns: 14.5rem minmax(0, 1fr); min-height: 100vh; }
.sidebar {
  position: sticky; top: 0; align-self: start; height: 100vh; overflow-y: auto;
  padding: 1.65rem 1rem; background: var(--sidebar, #101e2c); color: #fff;
}
.sidebar :focus-visible { outline-color: #a3ead1; outline-offset: 1px; }
.brand {
  display: flex; align-items: center; gap: .8rem; margin: 0 .45rem 1.35rem; color: #fff;
  text-decoration: none; font: 700 .96rem/1.18 var(--heading);
}
.mark { color: var(--highlight, #87dbc9); font: 700 1.9rem/1 var(--heading); letter-spacing: -.09em; }
.outline summary {
  cursor: pointer; padding: .65rem .78rem; border-radius: .5rem; background: #192e40;
  color: #f4fbfe; font-size: .79rem; font-weight: 700; list-style: none;
}
.outline summary::-webkit-details-marker { display: none; }
.module-title, .module-count { display: block; }
.module-count { margin-top: .35rem; color: #aac0d0; font-size: .68rem; font-weight: 400; }
.module-position { display: flex; gap: .2rem; margin-top: .38rem; }
.module-position span { flex: 1; height: .3rem; border-radius: .2rem; background: #2b4456; }
.module-position .earlier { background: var(--highlight, #87dbc9); }
.module-position .current { background: #507489; }
.module-sections, .steps { list-style: none; padding: 0; margin: .7rem 0 0; }
.sidebar :is(.module-item, .steps a) {
  display: flex; align-items: center; gap: .62rem; color: #d1dce4; text-decoration: none;
  line-height: 1.35; border-radius: .32rem;
}
.module-item { padding: .59rem .62rem; font-size: .84rem; }
.section-marker { position: relative; width: .87rem; height: .87rem; flex: none; border: 1.5px solid #7893a5; border-radius: 50%; }
.section-marker.earlier, .selected .section-marker { border-color: var(--highlight, #87dbc9); }
.selected .section-marker::after { position: absolute; content: ''; inset: .17rem; border-radius: 50%; background: var(--highlight, #87dbc9); }
.sidebar svg { width: .93rem; height: .93rem; flex: none; }
.sidebar :is(.module-item, .steps a):hover { background: #233644; color: #fff; }
.active-section { background: #172c3d; border-radius: .5rem; padding-bottom: .38rem; }
.sidebar .module-item.selected { color: #fff; font-weight: 700; }
.steps { margin: 0 0 0 1.2rem; }
.sidebar .steps a { padding: .42rem .35rem; gap: .3rem; font-size: .72rem; color: #adc2d2; }
.steps .step-icon { display: grid; place-items: center; width: .9rem; flex: none; color: var(--highlight, #87dbc9); }
.steps code { padding: 0; color: inherit; background: transparent; }
.sidebar .steps a[aria-current='page'] { background: #233c50; color: #fff; font-weight: 700; }
#course-sign-out { margin: .9rem .6rem; padding: .35rem 0; border: 0; background: transparent; color: #d1dce4; font: inherit; cursor: pointer; }
.course-index { display: block; margin: .9rem .6rem 0; color: #d1dce4; font-size: .84rem; }
main { width: 100%; max-width: 74rem; justify-self: center; padding: 1.2rem clamp(1rem, 6vw, 4.25rem) 2.5rem; }
.lesson-meta { display: flex; flex-wrap: wrap; gap: .5rem 1rem; justify-content: space-between; align-items: center; border-bottom: 1px solid var(--line); padding-bottom: .8rem; color: var(--muted); font-size: .84rem; }
.lesson-meta strong { color: var(--ink); font-weight: 600; }
.breadcrumb-separator { margin-inline: .35rem; }
.step-position, .step-position nav { display: flex; align-items: center; gap: .62rem; }
.step-position nav { gap: .2rem; }
.step-position a { display: grid; align-items: center; width: 1rem; min-height: 1.55rem; }
.step-position a::after { content: ''; height: .3rem; border-radius: .25rem; background: #cbd9dd; }
.step-position a.earlier::after { background: color-mix(in srgb, var(--accent) 38%, white); }
.step-position a[aria-current='step']::after { background: var(--accent); }
.readings-shortcut { display: inline-block; margin-top: .75rem; font-size: .84rem; }
h1, h2 { font-family: var(--heading); line-height: 1.16; }
h1 { margin: 2rem 0 .75rem; font-size: clamp(1.65rem, 3.1vw, 2.25rem); letter-spacing: -.025em; }
.overview-title { margin: 1.45rem 0 .8rem; font-size: 1.3rem; }
.readings h2 { margin: 0; font-size: 1.28rem; }
article p, article li { max-width: 70ch; }
article ol, article ul { padding-left: 1.4em; }
article li { padding-left: .25em; margin-block: .35em; }
blockquote { margin: 1.5rem 0; border-left: 3px solid #4d9987; padding: .75rem 1.15rem; background: #edf6f3; border-radius: 0 .35rem .35rem 0; }
blockquote p { margin: .3rem 0; }
.callout { margin: 1rem 0; border-inline-start: 3px solid var(--accent); border-radius: 0 .35rem .35rem 0; background: color-mix(in srgb, var(--accent) 8%, white); }
.callout summary { display: flex; align-items: baseline; gap: .55rem; padding: .65rem .85rem; cursor: pointer; list-style: none; }
.callout summary::-webkit-details-marker { display: none; }
.callout summary::after { content: ''; flex: none; align-self: center; width: .42rem; height: .42rem; margin-inline: auto .2rem; border: solid var(--accent); border-width: 0 2px 2px 0; transform: rotate(45deg); }
.callout[open] summary::after { transform: rotate(225deg); }
.callout summary:hover { background: color-mix(in srgb, var(--accent) 13%, white); }
.callout-body { padding: 0 .85rem .75rem 2.5rem; }
.callout-body > :first-child { margin-top: 0; }
.callout-body > :last-child { margin-bottom: 0; }
code { padding: .13em .25em; background: #edf1f1; border-radius: .2rem; font: .86em var(--mono); overflow-wrap: anywhere; }
pre { overflow: auto; padding: 1.05rem 1.2rem; border-radius: .45rem; background: #122a34; color: #eff8f6; }
pre code { padding: 0; background: transparent; overflow-wrap: normal; }
.table-scroll { overflow-x: auto; max-width: 100%; border-radius: .4rem; border: 1px solid var(--line); margin: 1.4rem 0; }
table { width: 100%; border-collapse: collapse; font-size: .9rem; line-height: 1.5; }
th, td { padding: .68rem .8rem; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
thead th { background: #edf3f2; color: #263f49; }
tbody tr:nth-child(even) { background: var(--wash); }
tbody tr:last-child > * { border-bottom: 0; }
.readings { margin: 2rem 0; border: 1px solid #b4cfca; border-radius: .55rem; }
.readings header { padding: 1.1rem 1.25rem; background: color-mix(in srgb, var(--accent) 9%, white); border-radius: .5rem .5rem 0 0; }
.readings header p { margin: .25rem 0 0; color: var(--muted); font-size: .84rem; }
.readings .table-scroll { margin: 0; border: 0; border-radius: 0 0 .5rem .5rem; }
.readings table { min-width: 40rem; font-variant-numeric: tabular-nums; }
.readings tbody tr:not(.baseline) { background: #fff; }
.readings tbody tr:nth-child(even):not(.baseline) { background: var(--wash); }
.readings th { vertical-align: middle; }
.readings input { width: 4.25rem; min-height: 2.4rem; padding: .3rem .4rem; color: var(--ink); background: white; border: 1px solid #839c9d; border-radius: .3rem; font: .87rem var(--mono); }
.readings input[type='text'] { width: 12rem; }
.interactive { margin-top: 2rem; }
.interactive iframe { display: block; width: 100%; height: 49rem; border: 1px solid var(--line); border-radius: .4rem; margin-top: .8rem; background: #fff; }
.catalogue { padding-inline-start: 1.5rem; }
.catalogue li { padding-block: .55rem; }
article details:not(.callout) { margin-block: .75rem; padding: .65rem .8rem; border: 1px solid var(--line); border-radius: .4rem; }
article details:not(.callout) summary { color: var(--accent); font-weight: 600; cursor: pointer; }
.baseline { background: color-mix(in srgb, var(--accent) 9%, white) !important; }
.baseline th { font-weight: 500; min-width: 10rem; }
.baseline td { vertical-align: middle; font: 500 .88rem var(--mono); }
.pager { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .75rem; margin-top: 2.25rem; padding-top: 1.1rem; border-top: 1px solid var(--line); }
.pager a {
  display: flex; align-items: center; gap: .6rem; width: min(100%, 17rem); min-height: 3.4rem;
  padding: .65rem .85rem; border-radius: .4rem; font-size: .87rem; line-height: 1.3; font-weight: 700; text-decoration: none;
}
.pager small { display: block; font-size: .74rem; font-weight: 500; }
.pager .back { background: color-mix(in srgb, var(--accent) 13%, white); color: var(--ink); }
.pager .back:hover { background: color-mix(in srgb, var(--accent) 21%, white); }
.pager .next { grid-column: 2; justify-self: end; justify-content: flex-end; text-align: right; background: var(--accent); color: #fff; }
.pager .next:hover { background: color-mix(in srgb, var(--accent) 80%, black); }
.pager .next code { color: inherit; background: transparent; padding: 0; }

@media (max-width: 760px) {
  .layout { display: block; }
  .sidebar { position: static; height: auto; padding: .8rem 1rem; }
  .brand { margin: 0 0 .65rem; }
  .outline summary { position: relative; padding-right: 2.1rem; }
  .outline summary::after { content: '▾'; position: absolute; right: .8rem; top: .65rem; }
  .outline[open] summary::after { content: '▴'; }
  .step-position a { width: 1.5rem; min-height: 1.75rem; }
  .table-scroll:not(.readings .table-scroll) table { min-width: 25rem; }
}

.platform-header { background: var(--sidebar); color: white; }
.platform-header-inner {
  display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap;
  gap: .25rem 1.5rem; max-width: 74rem; margin-inline: auto;
  padding: .8rem clamp(1rem, 6vw, 4.25rem);
}
.platform-header .brand { margin: 0; min-height: 2.75rem; }
.platform-logo { display: block; object-fit: contain; }
.platform-nav ul { display: flex; flex-wrap: wrap; gap: .2rem .4rem; padding: 0; margin: 0; list-style: none; }
.platform-nav a, .platform-menu summary {
  display: flex; align-items: center; min-height: 2.75rem; padding: .3rem .55rem;
  color: inherit; border-radius: .3rem; font-size: .88rem;
}
.platform-nav a { text-decoration: none; }
.platform-nav a:hover, .platform-nav [aria-current='page'] {
  color: var(--highlight); background: color-mix(in srgb, white 11%, transparent);
  text-decoration: underline;
}
.platform-header :focus-visible, .platform-menu :focus-visible { outline-color: var(--highlight); }
.platform-menu { margin-top: .35rem; color: #d1dce4; }
.platform-menu summary { display: list-item; cursor: pointer; }
.platform-menu .platform-nav ul { display: block; }
.platform-shell main { margin-inline: auto; }
.platform-shell h1 { max-width: 25ch; font-size: clamp(2rem, 4.5vw, 3.4rem); }
.platform-shell h2 { font-size: 1.35rem; }
.platform-shell .home-courses-title { font-size: 1.35rem; }
.platform-shell p { max-width: 68ch; }
.platform-intro { color: var(--muted); font-size: 1.12rem; }
.platform-hero.has-artwork {
  display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  align-items: center; gap: clamp(1rem, 4vw, 3rem); margin-block: 1.75rem 2rem;
}
.platform-hero.has-artwork h1 { margin-top: 0; }
.home-hero .platform-intro { margin: 0 0 1rem; }
.home-hero:not(.has-artwork) { margin-top: 1.75rem; }
.hero-image, .course-card-image { display: block; width: 100%; object-fit: cover; border-radius: .45rem; }
.hero-image { aspect-ratio: 3 / 2; }
.course-card-image { aspect-ratio: 2 / 1; margin-bottom: .85rem; }
@media (max-width: 640px) {
  .platform-hero.has-artwork { grid-template-columns: minmax(0, 1fr); }
}
.platform-section { margin-top: 2rem; }
.platform-back { margin-bottom: 0; }
.platform-button, .platform-shell #course-sign-out {
  display: inline-flex; align-items: center; min-height: 2.75rem; margin: 0;
  padding: .5rem 1rem; border: 1px solid var(--accent); border-radius: .35rem;
  font: inherit; font-weight: 700; background: var(--accent); color: white; text-decoration: none;
}
.platform-shell #course-sign-out[hidden] { display: none; }
.platform-button:hover, .platform-shell #course-sign-out:hover { background: color-mix(in srgb, var(--accent) 82%, black); }
.platform-form { margin-block: 1rem; }
.platform-form label { display: block; font-weight: 600; }
.platform-form input:not([type='hidden']), .platform-form select {
  display: block; width: min(100%, 23rem); min-height: 2.75rem; margin: .25rem 0 .6rem;
  padding: .4rem .55rem; font: inherit; border: 1px solid var(--muted); border-radius: .35rem;
}
.platform-form button:disabled { opacity: .65; }
.course-cards {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 20rem), 1fr));
  gap: .85rem; list-style: none; padding: 0;
}
.course-cards li { padding: 1rem 1.15rem; border: 1px solid var(--line); border-radius: .5rem; background: white; }
.course-cards :is(h2, h3) { margin: 0; font: 700 1.13rem/1.3 var(--heading); }
.course-cards p { margin: .5rem 0 0; }
.fixture-label, .course-cards .fixture-label { margin: 0 0 .4rem; color: var(--muted); font-size: .88rem; font-weight: 700; }
.fixture-label + h1 { margin-top: .25rem; }
.section-progress { margin-top: 2rem; }
.section-progress .platform-button { cursor: pointer; }
.section-progress .platform-button:disabled { opacity: .65; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }