site.css

/* Paper & Ink palette, shared with the viewer's default theme. */
:root {
  color-scheme: light dark;
  --bg: #f9f7f4;
  --surface: #f2efea;
  --raised: #ffffff;
  --border: #d8d3cc;
  --text: #1c1c1c;
  --muted: #5f5b55;
  --accent: #2f6db0;
  --focus: #2f6db0;
  --control: #8a847b;
  --tint: rgb(74 144 217 / 14%);
  --live: #2e6b45;
  --load: #8a5a00;
  --t-comment: #6b655d;
  --t-tag: #9c3d2e;
  --t-attr: #8a5a00;
  --t-string: #2e6b45;
  --t-keyword: #7f3f86;
  --t-function: #2f6db0;
  --t-number: #a1452a;

  --font: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --radius: 6px;
  --preview-width: clamp(360px, 42vw, 760px);
  /* The pages of one wide column, the org home and the H5P build page. Their prose keeps --measure. */
  --page-width: 72rem;
  --measure: 60ch;
}

@media (prefers-color-scheme: dark) {
  :root:not(:has(meta[name="color-scheme"][content="light"])) {
    --bg: #1b1a18;
    --surface: #242220;
    --raised: #26231f;
    --border: #3a3630;
    --text: #f2eee8;
    --muted: #a8a197;
    --accent: #7db0e4;
    --focus: #7db0e4;
    --control: #7d766b;
    --tint: rgb(125 176 228 / 18%);
    --live: #8fcf9f;
    --load: #e0b46a;
    --t-comment: #a39c91;
    --t-tag: #e8917f;
    --t-attr: #e0b46a;
    --t-string: #9fd19a;
    --t-keyword: #d6a0dc;
    --t-function: #7db0e4;
    --t-number: #e8a07f;
  }
}

:root:has(meta[name="color-scheme"][content="dark"]) {
  color-scheme: dark;
  --bg: #1b1a18;
  --surface: #242220;
  --raised: #26231f;
  --border: #3a3630;
  --text: #f2eee8;
  --muted: #a8a197;
  --accent: #7db0e4;
  --focus: #7db0e4;
  --control: #7d766b;
  --tint: rgb(125 176 228 / 18%);
  --live: #8fcf9f;
  --load: #e0b46a;
  --t-comment: #a39c91;
  --t-tag: #e8917f;
  --t-attr: #e0b46a;
  --t-string: #9fd19a;
  --t-keyword: #d6a0dc;
  --t-function: #7db0e4;
  --t-number: #e8a07f;
}

:root:has(meta[name="color-scheme"][content="light"]) {
  color-scheme: light;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 var(--font);
  -webkit-text-size-adjust: 100%;
}

a { color: var(--accent); text-underline-offset: 0.15em; }
a:hover { text-decoration-thickness: 2px; }

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

h1, h2, h3 { line-height: 1.25; text-wrap: balance; }
h2 { margin: 3rem 0 1rem; padding-top: 1.5rem; border-top: 1px solid var(--border); font-size: 1.5rem; }
h3 { margin: 2rem 0 0.5rem; font-size: 1.125rem; }
h2, h3 { scroll-margin-top: 1rem; }
p, ul, ol { margin: 0 0 1rem; }
li + li { margin-top: 0.25rem; }

code { font-family: var(--mono); font-size: 0.875em; }
:not(pre) > code {
  padding: 0.1em 0.35em;
  border-radius: 4px;
  background: var(--surface);
  overflow-wrap: anywhere;
}

blockquote {
  margin: 1.25rem 0;
  padding: 0.75rem 1rem;
  border-left: 3px solid var(--focus);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: var(--tint);
}
blockquote > :last-child { margin-bottom: 0; }

.skip-link {
  position: absolute;
  left: 1rem;
  top: -3rem;
  z-index: 100;
  padding: 0.5rem 1rem;
  background: var(--raised);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.skip-link:focus { top: 1rem; }

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

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

.button {
  display: inline-flex;
  align-items: center;
  gap: 0.35em;
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--raised);
  color: var(--text);
  font: inherit;
  font-size: 0.8125rem;
  line-height: 1.4;
  cursor: pointer;
}
.button:hover { background: var(--tint); }
.button-primary { border-color: var(--focus); color: var(--accent); font-weight: 600; }

/* Code blocks */
.code {
  margin: 1rem 0 1.25rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  overflow: hidden;
}
/* The preview pane's bar shares these, so it matches the Current markup bar below it. */
.code-bar, .preview-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.3rem 0.4rem 0.3rem 0.85rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.75rem;
  color: var(--muted);
}
.code-lang { margin-right: auto; text-transform: uppercase; letter-spacing: 0.04em; }
.code-bar .button, .preview-bar .button { font-size: 0.75rem; padding: 0.2rem 0.55rem; }

pre[class*="language-"] {
  margin: 0;
  padding: 0.85rem 1rem;
  overflow: auto;
  background: var(--surface);
  font: 0.8125rem/1.6 var(--mono);
  tab-size: 2;
}
pre[class*="language-"]:focus-visible { outline-offset: -2px; }
/* Before the script wraps it, a code block still needs a frame. */
pre[class*="language-"]:not(.code > pre) { margin: 1rem 0 1.25rem; border: 1px solid var(--border); border-radius: var(--radius); }

.token.comment, .token.prolog, .token.doctype { color: var(--t-comment); font-style: italic; }
.token.tag, .token.selector, .token.deleted { color: var(--t-tag); }
.token.attr-name, .token.property, .token.class-name { color: var(--t-attr); }
.token.string, .token.attr-value, .token.inserted { color: var(--t-string); }
.token.keyword, .token.atrule, .token.important { color: var(--t-keyword); }
.token.function, .token.builtin { color: var(--t-function); }
.token.number, .token.boolean, .token.constant { color: var(--t-number); }
.token.punctuation, .token.operator { color: var(--muted); }

/* Tables */
.table-wrap {
  margin: 1rem 0 1.5rem;
  overflow-x: auto;
  container-type: inline-size;
}
table { width: 100%; border-collapse: collapse; font-size: 0.875rem; }
th, td { padding: 0.55rem 0.6rem; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
thead th { font-size: 0.75rem; font-weight: 600; color: var(--muted); text-transform: uppercase; letter-spacing: 0.04em; }
tbody th { font-weight: normal; white-space: nowrap; }
tbody th a { color: inherit; text-decoration: none; }
tbody th a:hover code { text-decoration: underline; }
.attributes td.default { max-width: 14rem; overflow-wrap: anywhere; }
.attributes tr:target { background: var(--tint); }

.update { white-space: nowrap; font-size: 0.75rem; font-weight: 600; color: var(--muted); }
.update-live { color: var(--live); }
.update-load { color: var(--load); }

@container (width < 560px) {
  .attributes, .attributes tbody, .attributes tr, .attributes th, .attributes td { display: block; }
  .attributes thead { display: none; }
  .attributes tr { padding: 0.6rem 0; border-bottom: 1px solid var(--border); }
  .attributes th, .attributes td { padding: 0.1rem 0; border: 0; max-width: none; }
  .attributes td.default::before { content: "Default: "; color: var(--muted); }
  .attributes td:last-child::before { content: "Updates: "; color: var(--muted); font-weight: normal; }
}

/* Playground */
.playground {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 0.5rem 1rem;
  align-items: center;
  margin: 1rem 0 1.5rem;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
}
.playground .control { display: contents; }
.playground label { font-size: 0.875rem; }
.playground select, .playground input:not([type="checkbox"]) {
  width: 100%;
  max-width: 20rem;
  padding: 0.3rem 0.5rem;
  border: 1px solid var(--control);
  border-radius: var(--radius);
  background: var(--raised);
  color: var(--text);
  font: inherit;
  font-size: 0.875rem;
}
.playground select:hover, .playground input:not([type="checkbox"]):hover { border-color: var(--text); }

/* Customizable select for mouse and trackpad. Touch keeps the native picker; other browsers keep the styled native select. */
@media (pointer: fine) {
  @supports (appearance: base-select) {
    .playground select,
    .playground select::picker(select) { appearance: base-select; }

    .playground select {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 0.5rem;
      cursor: pointer;
      transition: border-color 0.15s;
    }
    .playground select:open { border-color: var(--focus); }
    .playground select::picker-icon {
      content: "";
      width: 0.75rem;
      height: 0.75rem;
      background: var(--muted);
      mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M2.5 4.5 6 8l3.5-3.5' fill='none' stroke='%23000' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center / contain no-repeat;
      transition: rotate 0.2s ease-out;
    }
    .playground select:open::picker-icon { rotate: 180deg; }

    .playground select::picker(select) {
      margin-block: 0.25rem;
      padding: 0.25rem;
      border: 1px solid var(--border);
      border-radius: var(--radius);
      background: var(--raised);
      color: var(--text);
      box-shadow: 0 8px 24px rgb(0 0 0 / 16%);
      opacity: 0;
      translate: 0 -0.25rem;
      transition:
        display 0.15s allow-discrete,
        overlay 0.15s allow-discrete,
        opacity 0.15s ease-out,
        translate 0.15s ease-out;
    }
    .playground select:open::picker(select) { opacity: 1; translate: 0 0; }
    @starting-style {
      .playground select:open::picker(select) { opacity: 0; translate: 0 -0.25rem; }
    }

    .playground option {
      gap: 0.5rem;
      padding: 0.35rem 0.6rem 0.35rem 0.4rem;
      border-radius: 4px;
      font-size: 0.875rem;
      cursor: pointer;
    }
    .playground option:hover { background: color-mix(in srgb, var(--text) 8%, transparent); }
    .playground option:focus-visible { outline: 2px solid var(--focus); outline-offset: -2px; }
    /* Checked: checkmark, weight and background, so the state isn't carried by color alone. */
    .playground option:checked { font-weight: 600; background: var(--tint); }
    .playground option::checkmark { color: var(--focus); }
  }
}

.playground input[type="checkbox"] { justify-self: start; width: 1.25rem; height: 1.25rem; margin: 0; accent-color: var(--focus); }
.playground-hint { grid-column: 1 / -1; margin: 0 0 0.25rem; font-size: 0.8125rem; color: var(--muted); }

/* Docs layout: table of contents | content | preview */
.docs {
  display: grid;
  grid-template-columns: minmax(0, 1fr) var(--preview-width);
}

.toc {
  display: none;
  position: sticky;
  top: 0;
  height: 100dvh;
  overflow-y: auto;
  padding: 1.5rem 1rem 2rem 1.5rem;
  border-right: 1px solid var(--border);
  font-size: 0.875rem;
  scroll-target-group: auto;
}
.brand { display: inline-flex; align-items: center; gap: 0.5rem; color: var(--text); font-weight: 600; text-decoration: none; }
.brand img { width: 1.5rem; height: 1.5rem; }
.brand:hover { text-decoration: underline; }
.toc-home { margin-bottom: 1.25rem; }
.docs-brand { margin-bottom: 1.25rem; font-size: 0.9375rem; }
.toc ol, .toc-inline ol { margin: 0; padding: 0; list-style: none; }
.toc li + li, .toc-inline li + li { margin-top: 0; }
.toc ol a, .toc-inline a {
  display: block;
  padding: 0.2rem 0.5rem;
  border-left: 2px solid transparent;
  color: var(--muted);
  text-decoration: none;
}
.toc ol a:hover { color: var(--text); }
.toc ol a:is(:target-current, .\:target-current) { border-left-color: var(--focus); color: var(--text); font-weight: 600; }
:is(.toc, .toc-inline) .toc-l3 a { padding-left: 1.25rem; font-size: 0.8125rem; }

.content {
  min-width: 0;
  width: 100%;
  max-width: 48rem;
  margin-inline: auto;
  padding: 2rem clamp(1rem, 4vw, 3rem) 4rem;
}

.docs-header { margin-bottom: 2rem; }
.docs-header h1 { margin: 0; font-size: 2.25rem; letter-spacing: -0.01em; }
.docs-header-row { display: flex; align-items: center; gap: 1rem; justify-content: space-between; }
.lead { margin: 0.5rem 0 0.75rem; font-size: 1.125rem; color: var(--muted); }
.meta { display: flex; flex-wrap: wrap; gap: 0.25rem 1rem; margin: 0 0 1rem; padding: 0; list-style: none; font-size: 0.875rem; color: var(--muted); }
.meta li + li { margin-top: 0; }

.toc-inline { margin: 1rem 0 0; border: 1px solid var(--border); border-radius: var(--radius); font-size: 0.875rem; }
.toc-inline summary { padding: 0.5rem 0.75rem; cursor: pointer; font-weight: 600; }
.toc-inline ol { padding: 0 0.5rem 0.5rem; }

.docs-footer { margin-top: 4rem; padding-top: 1rem; border-top: 1px solid var(--border); font-size: 0.875rem; color: var(--muted); }

/* Theme switch: the knob sits on the sun when light and on the moon when dark. */
.theme-switch {
  --track-pad: 0.1875rem;
  --knob: 1.5rem;
  position: relative;
  flex: none;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  justify-items: center;
  width: 3.5rem;
  height: 1.875rem;
  padding: 0 var(--track-pad);
  border: 1px solid var(--control);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
}
.theme-switch:not([hidden]) { display: inline-grid; }
.theme-switch input {
  position: absolute;
  inset: 0;
  z-index: 2;
  width: 100%;
  height: 100%;
  margin: 0;
  appearance: none;
  border-radius: inherit;
  cursor: pointer;
}
.theme-switch:has(input:focus-visible) { outline: 2px solid var(--focus); outline-offset: 2px; }
.theme-switch input:focus-visible { outline: none; }
.theme-switch-knob {
  position: absolute;
  top: 50%;
  left: var(--track-pad);
  width: var(--knob);
  height: var(--knob);
  border-radius: 50%;
  background: var(--text);
  box-shadow: 0 1px 2px rgb(0 0 0 / 25%);
  transform: translateY(-50%);
  transition: transform 0.15s ease-out;
}
.theme-switch input:checked ~ .theme-switch-knob {
  transform: translate(calc(3.5rem - 2px - 2 * var(--track-pad) - var(--knob)), -50%);
}
.theme-switch svg {
  position: relative;
  z-index: 1;
  width: 0.95rem;
  height: 0.95rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.theme-switch input:not(:checked) ~ .theme-switch-sun,
.theme-switch input:checked ~ .theme-switch-moon { color: var(--bg); }

/* Preview pane */
.preview {
  position: sticky;
  top: 0;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  border-left: 1px solid var(--border);
  background: var(--surface);
}
.preview-title { margin-right: auto; font-weight: 600; }
.preview-close { display: none; }
.preview-stage { position: relative; flex: 1; min-height: 0; }
.preview-stage pdfjs-viewer-element { height: 100%; }
.preview-note { padding: 1rem; color: var(--muted); }
.preview .code { margin: 0; border: 0; border-top: 1px solid var(--border); border-radius: 0; }
.preview .code-lang { text-transform: none; letter-spacing: 0; font-weight: 600; }

/* Decorative label icons, masked so they take a color like text does. */
.preview-title, .preview .code-lang { display: inline-flex; align-items: center; gap: 0.4rem; }
.preview-title::before, .preview .code-lang::before {
  content: "";
  flex: none;
  width: 1rem;
  height: 1rem;
  background: var(--focus);
  mask: var(--icon) center / contain no-repeat;
}
.preview-title {
  --icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M2 12s3.5-7 10-7 10 7 10 7-3.5 7-10 7S2 12 2 12Z'/%3E%3Ccircle cx='12' cy='12' r='3'/%3E%3C/svg%3E");
}
.preview .code-lang {
  --icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m16 18 6-6-6-6M8 6l-6 6 6 6'/%3E%3C/svg%3E");
}
/* Grows with the markup, so a typical setup shows in full; past a third of the screen it scrolls,
   leaving the viewer most of the pane. */
.preview pre.preview-markup { max-height: 35dvh; padding: 0.5rem 0.75rem; background: var(--bg); font-size: 0.75rem; }
.preview-markup code { white-space: pre-wrap; overflow-wrap: anywhere; }

.flash { animation: flash 0.6s ease-out; }
@keyframes flash { from { box-shadow: inset 0 0 0 3px var(--focus); } to { box-shadow: inset 0 0 0 3px transparent; } }

@media (min-width: 1280px) {
  .docs { grid-template-columns: 15rem minmax(0, 1fr) var(--preview-width); }
  .toc { display: block; }
  .toc-inline, .docs-brand { display: none; }
}

/* Below 1000px the preview becomes a full-screen panel opened from a floating button. */
@media (max-width: 999px) {
  .docs { grid-template-columns: minmax(0, 1fr); }
  .preview {
    position: fixed;
    inset: 0;
    z-index: 50;
    height: auto;
    border: 0;
    visibility: hidden;
    transform: translateY(100%);
    transition: transform 0.2s ease-out, visibility 0s linear 0.2s;
  }
  .preview[data-open] { visibility: visible; transform: none; transition: transform 0.2s ease-out; }
  .preview-close { display: inline-flex; }
  .preview-open {
    position: fixed;
    right: 1rem;
    bottom: 1rem;
    z-index: 40;
    padding: 0.6rem 1rem;
    border-color: var(--focus);
    color: var(--accent);
    font-size: 0.875rem;
    font-weight: 600;
    box-shadow: 0 2px 10px rgb(0 0 0 / 18%);
  }
  .preview-open:not([hidden]) { display: inline-flex; }
  html:has(.preview[data-open]) { overflow: hidden; }
}
@media (min-width: 1000px) {
  .preview-open { display: none; }
}

/* Forced colors paint transparent borders, so give the TOC marker system colors. */
@media (forced-colors: active) {
  /* Masked icons paint with their background, which forced colors would turn into Canvas. */
  .preview-title::before, .preview .code-lang::before, .playground select::picker-icon { forced-color-adjust: none; background: CanvasText; }
  .theme-switch-knob { border: 1px solid CanvasText; }
  .toc ol a { border-left-color: Canvas; }
  .toc ol a:is(:target-current, .\:target-current) { border-left-color: Highlight; }
}

@media (prefers-reduced-motion: reduce) {
  .preview, .preview[data-open], .theme-switch-knob { transition: none; }
  .playground select, .playground select::picker(select), .playground select::picker-icon { transition: none; }
  .flash { animation: none; }
}

/* Org home */
.home { max-width: var(--page-width); margin: 0 auto; padding: 4rem clamp(1rem, 4vw, 3rem); }
.home h1 { margin: 0 0 0.5rem; font-size: 2rem; }
.brand-title { display: flex; align-items: center; gap: 0.75rem; }
.brand-title img { width: 3rem; height: 3rem; }
.home .lead { max-width: var(--measure); margin-bottom: 2rem; }
/* A group of cards under its title, the size of a docs page's section title, without its rule. */
.home section + section { margin-top: 3rem; }
.home section > h2 { margin: 0 0 0.75rem; padding: 0; border: 0; font-size: 1.5rem; }
.home section > p { max-width: var(--measure); margin: 0 0 1.25rem; color: var(--muted); }
/* The cards two to a row where two fit, each as tall as its row, with its links at its foot. Every
   section has the same two columns, so a section of one card keeps it the width of the others. */
.home section { container-type: inline-size; }
.elements {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}
@container (width > 36rem) {
  .elements { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
.elements li { display: flex; flex-direction: column; margin: 0; padding: 1rem 1.25rem; border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); }
.elements h3 { margin: 0 0 0.25rem; font-size: 1.125rem; }
.elements p { margin: 0 0 0.5rem; color: var(--muted); }
.elements .links { display: flex; gap: 1rem; margin-top: auto; font-size: 0.875rem; }
/* The home page's footer: where else the elements are, in columns of links. */
.site-footer { margin-top: 4rem; padding-top: 1.5rem; border-top: 1px solid var(--border); font-size: 0.875rem; }
.footer-links { display: flex; flex-wrap: wrap; gap: 1.5rem 4rem; }
.footer-links h2 { margin: 0 0 0.5rem; padding: 0; border: 0; font-size: 0.875rem; }
.footer-links ul { margin: 0; padding: 0; list-style: none; }
.footer-links li + li { margin-top: 0.35rem; }
.footer-links a { color: var(--muted); text-decoration: none; }
.footer-links a:hover { color: var(--text); text-decoration: underline; }

/* The H5P pages, the build page and the skill's: one wide column, its prose at --measure, and its
   sections as steps. */
:is(.build, .skill) { max-width: var(--page-width); }
.build-brand { margin-bottom: 1.25rem; font-size: 0.9375rem; }
/* A longer heading than the docs' package names, so it gives way on a phone. */
:is(.build, .skill) .docs-header h1 { font-size: clamp(1.75rem, 1.2rem + 3vw, 2.25rem); }
/* Prose keeps a line a reader can follow; the source, the lists and what plays take the whole width. */
:is(.build, .skill) p:not(.status) { max-width: var(--measure); }

/* H5P build page, /h5p/build/ */
.build {
  --ok: var(--live);
  --bad: var(--t-tag);
  /* Masked, like the preview pane's icons, so they take a color like text does. */
  --icon-check: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m5 12.5 4.5 4.5L19 7.5'/%3E%3C/svg%3E");
  --icon-alert: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='3' stroke-linecap='round'%3E%3Cpath d='M12 5v8.5M12 18.5v.01'/%3E%3C/svg%3E");
}
/* The steps are a timeline, on this page and the skill's: a marker for each, on a rail that runs on
   to the next. A step the page hides, as the files of a source that names none, is not on it, and
   the rail ends at the last shown. How a step stands, done or wrong, is the build page's alone. */
.step {
  --marker: 2rem;
  --indent: calc(var(--marker) + 1rem);
  /* How the step stands, which the rules under these set from what the page says of it. */
  --step-color: var(--accent);
  --step-fill: var(--bg);
  --step-rail: var(--border);
  --step-marked: 0;
  position: relative;
  padding: 0 0 1.5rem var(--indent);
}
.docs-header + .step { margin-top: 2.5rem; }
/* The source is JSON, every file it names is chosen, the build is ready: the step is done. */
.build .step:is(
  :has(#source-state[data-state="ok"]),
  :has(.file-list > li):not(:has(.file-list > [data-chosen="false"])),
  :has(.status[data-state="ready"])
) {
  --step-fill: var(--accent);
  --step-rail: var(--accent);
  --step-marked: 1;
  --step-icon: var(--icon-check);
}
/* The text is not JSON, or nothing was built. */
.build .step:has(#source-state[data-state="error"], .status[data-state="error"]) {
  --step-color: var(--bad);
  --step-fill: var(--bad);
  --step-marked: 1;
  --step-icon: var(--icon-alert);
}

/* The rail, from under a step's marker to the next one's. It is a border, which forced colors keep. */
.step::before {
  content: "";
  position: absolute;
  top: calc(var(--marker) + 0.5rem);
  bottom: 0.5rem;
  left: calc(var(--marker) / 2 - 1px);
  border-left: 2px solid var(--step-rail);
  transform-origin: top;
  transition: border-color 0.2s, opacity 0.3s, scale 0.3s ease-out;
}
/* None from the last step shown: it is drawn down to a step as that one joins. */
.step:not(:has(~ .step:not([hidden])))::before { opacity: 0; }
/* A step that joins the others, the files or the play, comes in. */
#files-step, #play-step { transition: opacity 0.3s ease-out, translate 0.3s ease-out; }
@starting-style {
  #files-step, #play-step { opacity: 0; }
}

.step h2 {
  display: flex;
  align-items: center;
  min-height: var(--marker);
  margin: 0 0 0.75rem;
  padding: 0;
  border: 0;
  font-size: 1.25rem;
}
.build h3 { margin: 1.5rem 0 0.5rem; font-size: 1rem; }
.step-marker {
  position: absolute;
  top: 0;
  left: 0;
  display: grid;
  place-items: center;
  width: var(--marker);
  height: var(--marker);
  border: 2px solid var(--step-color);
  border-radius: 50%;
  background: var(--step-fill);
  color: var(--step-color);
  font-size: 0.875rem;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  transition: border-color 0.2s, background-color 0.2s, color 0.2s;
}
/* A check or a warning takes the number's place. The number stays in the heading's name. */
.step-number { opacity: calc(1 - var(--step-marked)); transition: opacity 0.2s; }
.step-marker::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--bg);
  mask: var(--step-icon, none) center / 1.125rem no-repeat;
  opacity: var(--step-marked);
  transition: opacity 0.2s;
}
/* While it builds, and until what was built plays, a ring around the marker, which turns. */
.step-marker::before {
  content: "";
  position: absolute;
  inset: -0.3125rem;
  border: 2px solid var(--tint);
  border-top-color: var(--accent);
  border-radius: 50%;
  opacity: 0;
  transition: opacity 0.2s;
}
.build .step:has(.status[data-state="building"]) .step-marker::before { opacity: 1; }
@keyframes turn { to { rotate: 1turn; } }

.build label { display: block; margin-bottom: 0.35rem; font-weight: 600; }
.build label.inline-label { display: inline; margin-right: 0.5rem; }
.build textarea {
  display: block;
  width: 100%;
  min-height: 12rem;
  resize: vertical;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--control);
  border-radius: var(--radius);
  background: var(--raised);
  color: var(--text);
  font: 0.8125rem/1.6 var(--mono);
}
.build textarea:hover { border-color: var(--text); }
/* The source's editor hides its textarea, which stays under it as the field the page reads. */
.build textarea[hidden] { display: none; }
.build .field { margin: 0 0 0.5rem; }
.source-editor { display: block; }
/* A line of its own, kept when it is empty, so that what is under it does not move as a mistake comes and goes:
   two lines where the column is narrow enough for a message to wrap. */
.build #source-state { margin: 0.5rem 0 0.25rem; min-height: 1.5em; }
@media (max-width: 700px) { .build #source-state { min-height: 3em; } }
.build #source-state[data-state="error"] { color: var(--bad); }
.build .link-button, .build .problems .jump {
  padding: 0; border: 0; background: none; color: var(--accent); font: inherit; text-decoration: underline; cursor: pointer;
}
.build .problems .jump code { color: inherit; }
.build input[type="file"] { max-width: 100%; font: inherit; font-size: 0.875rem; color: var(--muted); }
.build input[type="file"]::file-selector-button {
  margin-right: 0.6rem;
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--raised);
  color: var(--text);
  font: inherit;
  cursor: pointer;
}
.build input[type="file"]::file-selector-button:hover { background: var(--tint); }
.build a.button { text-decoration: none; }
.button-large { padding: 0.55rem 1.1rem; font-size: 0.9375rem; }
/* The page's two main actions, Build and Download, filled where the site's other buttons are outlined. */
.button-solid, .button-solid:hover { border-color: var(--accent); background: var(--accent); color: var(--bg); font-weight: 600; }
.button-solid:hover:not(:disabled) { border-color: transparent; background: color-mix(in oklab, var(--accent) 85%, var(--text)); }
.build .button:disabled { opacity: 0.6; cursor: progress; }
.build .status {
  padding: 0.6rem 0.85rem;
  border-left: 3px solid var(--border);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: var(--surface);
}
.build .status:empty { display: none; }
.build .status[data-state="building"] { border-left-color: var(--focus); background: var(--tint); }
.build .status[data-state="ready"] { border-left-color: var(--ok); }
.build .status[data-state="error"] { border-left-color: var(--bad); }
/* The problems, the notes and the files, a row each; on the skill page, its addresses. */
.build .messages, .build .file-list, .skill-files {
  padding: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--raised);
  list-style: none;
}
.build .messages li, .build .file-list li, .skill-files li { margin: 0; padding: 0.55rem 0.85rem; overflow-wrap: anywhere; }
.build .messages li + li, .build .file-list li + li, .skill-files li + li { border-top: 1px solid var(--border); }
/* A whole address in the site's mono font, and what the file is, muted, after it. */
.skill-files { color: var(--muted); }
.skill-files li { font-size: 0.875rem; }
.skill-files a { font-family: var(--mono); font-size: 0.9375em; }
/* A file's name, then whether it is chosen: at the row's end where both fit on a line, under the name where they do not. */
.build .file-list li {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0 0.6rem;
  padding-left: 2.45rem;
  white-space: nowrap;
}
.build .file-list code { white-space: normal; }
/* Beside the name's first line: a ring to fill, then a check. */
.build .file-list li::before {
  content: "";
  position: absolute;
  top: 0.85rem;
  left: 0.85rem;
  width: 1rem;
  height: 1rem;
  border: 2px dotted var(--control);
  border-radius: 50%;
}
.build .file-list li[data-chosen="true"]::before { border: 0; border-radius: 0; background: var(--accent); mask: var(--icon-check) center / contain no-repeat; }
.build .file-list li[data-chosen="false"] { color: var(--muted); }
.build .hint { color: var(--muted); font-size: 0.875rem; }
/* H5P content draws on white, whatever the page's theme. */
.player-box { margin: 1rem 0; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; background: #ffffff; }
.player-box h5p-player { display: block; }

@media (max-width: 480px) {
  .step { --marker: 1.75rem; --indent: calc(var(--marker) + 0.75rem); }
  .step-marker { font-size: 0.8125rem; }
  /* The last step has no rail beside it, so on a phone what plays takes the column's whole width. */
  .player-box { margin-left: calc(-1 * var(--indent)); }
}

/* A finger's target. */
@media (pointer: coarse) {
  .button-large { min-height: 2.75rem; }
  .build input[type="file"]::file-selector-button { padding-block: 0.6rem; }
}

/* What moves, only where motion is not asked to be reduced: the rail drawn down, a step coming up, the ring turning. */
@media (prefers-reduced-motion: no-preference) {
  .step:not(:has(~ .step:not([hidden])))::before { scale: 1 0; }
  @starting-style {
    #files-step, #play-step { translate: 0 0.5rem; }
  }
  .build .step:has(.status[data-state="building"]) .step-marker::before { animation: turn 0.9s linear infinite; }
}

@media (forced-colors: active) {
  /* Masked icons paint with their background, which forced colors would turn into Canvas. */
  .step-marker::after, .build .file-list li[data-chosen="true"]::before { forced-color-adjust: none; background: CanvasText; }
  .step-marker::before { border-color: GrayText; border-top-color: Highlight; }
}