/* The PRA book — impire reading theme.
   Two themes survive the stock five: Light is impire.io's cool violet-cast
   paper with PRA blue; Navy is the pre-migration impire night sky (the
   palette the explainer still uses). Auto follows the reader's scheme.

   The signature is the book's own two-lane rule made visible: story prose
   sits in a quiet book serif; every "Under the hood" blockquote shifts into
   the engineering voice — sans text, mono eyebrow label, PRA-blue keel. */

/* mdBook sets html { font-size: 62.5% } — 1rem is 10px here; content type
   below anchors on px and scales inner elements with em */
:root {
  --content-max-width: 66rem;
  --mono-font: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, monospace;
  --impire-serif: 'Iowan Old Style', Charter, Georgia, Cambria, 'Times New Roman', serif;
  --impire-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  --impire-display: 'Bricolage Grotesque', var(--impire-sans);
}

/* ---------- day: impire paper ---------- */

.light {
  --bg: #f8f7fb;
  --fg: #1b1f2c;
  --sidebar-bg: #fbfafd;
  --sidebar-fg: #454b60;
  --sidebar-non-existant: #aeb0bf;
  --sidebar-active: #0f62c4;
  --sidebar-spacer: #e8e6f0;
  --scrollbar: #cbc8da;
  --icons: #626779;
  --icons-hover: #0f62c4;
  --links: #0f62c4;
  --inline-code-color: #1b1f2c;
  --theme-popup-bg: #ffffff;
  --theme-popup-border: #e3e1ec;
  --theme-hover: #f1eff7;
  --quote-bg: #ffffff;
  --quote-border: #e3e1ec;
  --table-border-color: #e3e1ec;
  --table-header-bg: #f1eff7;
  --table-alternate-bg: #f4f2f9;
  --searchbar-border-color: #cbc8da;
  --searchbar-bg: #ffffff;
  --searchbar-fg: #1b1f2c;
  --searchresults-border-color: #e3e1ec;
  --searchresults-li-bg: #f8f7fb;
  --search-mark-bg: #cfe6ff;
  --footnote-highlight: #5eb1ff;
}

/* ---------- night: the old impire night sky ---------- */

.navy {
  --bg: #0e1116;
  --fg: #dde3ec;
  --sidebar-bg: #161b23;
  --sidebar-fg: #a6afbf;
  --sidebar-non-existant: #4a5364;
  --sidebar-active: #5eb1ff;
  --sidebar-spacer: #2a3342;
  --scrollbar: #2a3342;
  --icons: #8a94a6;
  --icons-hover: #5eb1ff;
  --links: #5eb1ff;
  --inline-code-color: #dde3ec;
  --theme-popup-bg: #161b23;
  --theme-popup-border: #2a3342;
  --theme-hover: #1c2330;
  --quote-bg: #161b23;
  --quote-border: #2a3342;
  --table-border-color: #2a3342;
  --table-header-bg: #1c2330;
  --table-alternate-bg: #131820;
  --searchbar-border-color: #2a3342;
  --searchbar-bg: #161b23;
  --searchbar-fg: #dde3ec;
  --searchresults-border-color: #2a3342;
  --searchresults-li-bg: #131820;
  --search-mark-bg: #24507e;
  --footnote-highlight: #24507e;
  --overlay-bg: rgba(8, 10, 14, 0.5);
}

/* the other stock themes leave the picker: Auto / Light / Navy remain */
#mdbook-theme-rust,
#mdbook-theme-coal,
#mdbook-theme-ayu {
  display: none;
}

/* ---------- type: the story lane ---------- */

html {
  font-family: var(--impire-serif);
}

.content main {
  font-size: 17px;
  line-height: 1.68;
}

.content p {
  text-wrap: pretty;
}

h1, h2, h3, h4, h5 {
  font-family: var(--impire-display);
  font-weight: 620;
  letter-spacing: -0.012em;
  text-wrap: balance;
}

.content h1 {
  font-size: 2.05em;
  line-height: 1.15;
}

/* the keel under a chapter title — same stroke the boxes carry */
.content h1::after {
  content: '';
  display: block;
  width: 52px;
  height: 3px;
  margin-top: 14px;
  border-radius: 2px;
  background: var(--links);
  opacity: 0.85;
}

.content h2 {
  font-size: 1.45em;
  margin-block-start: 2.4em;
}

.menu-title {
  font-family: var(--impire-display);
  font-weight: 600;
  letter-spacing: 0.01em;
}

/* ---------- chrome: the navigation rail ---------- */

#mdbook-sidebar {
  font-size: 15px;
  border-right: 1px solid var(--sidebar-spacer);
}

#mdbook-sidebar .sidebar-scrollbox {
  padding: 18px 14px;
}

/* part titles are mono eyebrows at the rail edge */
.chapter li.part-title {
  margin: 26px 6px 6px;
  font-family: var(--mono-font);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--icons);
}

.chapter li.chapter-item {
  margin-block-start: 2px;
  line-height: 1.45;
}

/* the link is a flex row: mono number in a fixed slot, sans title beside
   it — wrapped title lines stay aligned after the number */
.chapter li a {
  display: flex;
  flex: 1;
  align-items: baseline;
  padding: 6px 10px;
  border-radius: 8px;
  font-family: var(--impire-sans);
}

.chapter li a strong {
  flex: none;
  width: 32px;
  font-family: var(--mono-font);
  font-size: 12.5px;
  font-weight: 600;
  color: var(--links);
  opacity: 0.8;
}

.chapter li a:hover {
  color: var(--sidebar-active);
  background: color-mix(in srgb, var(--links) 7%, transparent);
}

.chapter li a.active {
  color: var(--sidebar-active);
  font-weight: 600;
  background: color-mix(in srgb, var(--links) 11%, transparent);
}

.chapter li a.active strong {
  opacity: 1;
}

/* ---------- links ---------- */

.content a {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  text-decoration-color: color-mix(in srgb, var(--links) 45%, transparent);
}

.content a:hover {
  text-decoration-color: var(--links);
}

::selection {
  background: rgba(94, 177, 255, 0.35);
}

/* ---------- the engineering lane: "Under the hood" boxes ---------- */

.content blockquote {
  font-family: var(--impire-sans);
  font-size: 0.92em;
  line-height: 1.58;
  background: var(--quote-bg);
  border: 1px solid var(--quote-border);
  border-left: 3px solid var(--links);
  border-radius: 8px;
  padding: 14px 18px;
  margin: 1.7em 0;
}

.content blockquote > p:first-child > strong:first-child {
  display: block;
  margin-bottom: 6px;
  font-family: var(--mono-font);
  font-size: 0.82em;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--links);
}