/* The site's layout: header, navigation, footer, and the blog. Loaded after
   minimal.css, which styles the content (and the dev pages under Vite) and
   defines the colours (--vs-*). */

:root {
  --measure: 840px;
  --wide: 960px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  /* Short and long pages center the same, so the header stays put. */
  scrollbar-gutter: stable;
}

body {
  /* minimal.css narrows the body; here the main column does. */
  max-width: none;
  padding: 0;
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--vs-bg);
  color: var(--vs-text);
  font-family:
    system-ui,
    -apple-system,
    "Segoe UI",
    Roboto,
    Helvetica,
    Arial,
    sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--vs-link);
}

img {
  max-width: 100%;
  height: auto;
}

/* In the dark, the black inscription turns white, and the content's images
   keep the white they were drawn on: diagrams with transparent backgrounds
   would vanish otherwise. Photos and screenshots are opaque anyway. */
@media (prefers-color-scheme: dark) {
  .brand-inscription {
    filter: invert(1);
  }

  main img {
    background: #fff;
  }
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  padding: 8px 12px;
  background: var(--vs-surface);
  z-index: 10;
}

.skip-link:focus {
  left: 8px;
  top: 8px;
}

/* Header */

.site-header {
  background: var(--vs-surface);
  border-bottom: 1px solid var(--vs-border);
}

.site-header-inner {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 10px 20px;
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-areas: "brand nav lang";
  align-items: center;
  gap: 8px 16px;
}

.brand {
  grid-area: brand;
  display: flex;
  align-items: center;
  gap: 10px;
  color: inherit;
  text-decoration: none;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-name {
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.01em;
}

.brand-inscription {
  margin-top: 4px;
  opacity: 0.75;
}

.site-nav {
  grid-area: nav;
  justify-self: end;
}

.lang-switch {
  grid-area: lang;
  border-left: 1px solid var(--vs-border);
  padding-left: 12px;
}

.site-nav ul,
.lang-switch ul {
  display: flex;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav a,
.lang-switch a,
.lang-switch span,
.lang-switch button {
  display: block;
  padding: 6px 10px;
  border-radius: 6px;
  color: var(--vs-text);
  text-decoration: none;
  font-size: 0.95rem;
  white-space: nowrap;
}

.site-nav a:hover,
.lang-switch a:hover,
.lang-switch button:hover {
  background: var(--vs-bg);
}

/* No bolder weight: the wider text would move the items after it. */
.site-nav a[aria-current="page"] {
  color: var(--vs-accent);
  box-shadow: inset 0 -2px 0 var(--vs-accent);
  border-radius: 6px 6px 0 0;
}

.lang-switch button {
  border: none;
  background: none;
  font-family: inherit;
  line-height: inherit;
  cursor: pointer;
}

.lang-switch a,
.lang-switch span,
.lang-switch button {
  padding: 4px 8px;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.lang-switch a,
.lang-switch button {
  color: var(--vs-muted);
}

/* The current language: on bilingual pages, <html lang> is the site's
   language (site_lang.js sets it before the page renders). */
.lang-switch span[aria-current],
html[lang="en"] .lang-switch button[data-site-lang="en"],
html[lang="de"] .lang-switch button[data-site-lang="de"] {
  background: var(--vs-text);
  color: var(--vs-surface);
  cursor: default;
}

/* Bilingual pages carry both languages; only the current one shows: the
   header's and footer's variants, those of the page's own text (class
   i18n-variant, lang="..."), and <lang-switch>'s blocks (also before the
   element is defined). */
html[data-bilingual][lang="en"] .i18n-variant:not([lang="en"]),
html[data-bilingual][lang="de"] .i18n-variant:not([lang="de"]),
html[data-bilingual][lang="en"] lang-switch > [lang]:not([lang="en"]),
html[data-bilingual][lang="de"] lang-switch > [lang]:not([lang="de"]) {
  display: none;
}

/* Narrow screens: brand and language on top, the nav below it, scrolling
   sideways rather than wrapping. */
@media (max-width: 640px) {
  .site-header-inner {
    grid-template-columns: 1fr auto;
    grid-template-areas:
      "brand lang"
      "nav nav";
    padding: 10px 12px 0;
  }
  .site-nav {
    justify-self: stretch;
    margin: 0 -12px;
    overflow-x: auto;
    border-top: 1px solid var(--vs-bg);
  }
  .site-nav ul {
    padding: 0 6px;
  }
  .lang-switch {
    border-left: none;
    padding-left: 0;
  }
}

/* Main column */

/* The page's title (or, without one, its content) starts as far below the
   header as a section's heading below the section before it. */
main {
  flex: 1;
  width: 100%;
  max-width: var(--measure);
  margin: 0 auto;
  padding: 32px 20px 40px;
}

@media (max-width: 640px) {
  main {
    padding-top: 24px;
  }
}

/* Headings: smaller and lighter than the browser's, and closer to the text
   they head than to the text before them. */
h1,
h2,
h3,
h4 {
  font-weight: 600;
  line-height: 1.3;
}

/* The title is the page's first line, or follows the breadcrumb; the
   content follows it a little further than a paragraph its predecessor. */
h1 {
  margin: 0 0 20px;
  border-bottom: 1px solid var(--vs-border);
  padding-bottom: 5px;
  font-size: 1.75rem;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

@media (max-width: 640px) {
  h1 {
    font-size: 1.5rem;
  }
}

h2 {
  margin: 1.6em 0 0.5em;
  font-size: 1.4rem;
}

h3 {
  margin: 1.4em 0 0.4em;
  font-size: 1.15rem;
}

h4 {
  margin: 1.3em 0 0.3em;
  font-size: 1rem;
}

.lede {
  color: var(--vs-muted);
  font-size: 1.1rem;
}

.breadcrumb {
  margin: 0 0 8px;
  font-size: 0.9rem;
}

.breadcrumb a {
  color: var(--vs-muted);
  text-decoration: none;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

/* Blog */

.post-header h1 {
  margin: 0 0 8px;
}

.post-meta {
  margin: 0;
  color: var(--vs-muted);
  font-size: 0.9rem;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
}

.tags a {
  display: inline-block;
  padding: 1px 10px;
  border: 1px solid var(--vs-border);
  border-radius: 999px;
  background: var(--vs-surface);
  color: var(--vs-muted);
  font-size: 0.8rem;
  text-decoration: none;
}

.tags a:hover {
  border-color: var(--vs-muted);
  color: var(--vs-text);
}

.tags .count {
  margin-left: 4px;
  padding: 0 6px;
  border-radius: 999px;
  background: var(--vs-bg);
  font-size: 0.75rem;
}

.post-list {
  margin: 24px 0;
  padding: 0;
  list-style: none;
}

.post-summary {
  padding: 18px 0;
  border-bottom: 1px solid var(--vs-border);
}

.post-summary:first-child {
  padding-top: 0;
}

.post-summary h2 {
  margin: 0 0 4px;
  font-size: 1.3rem;
  line-height: 1.3;
}

.post-summary h2 a {
  color: inherit;
  text-decoration: none;
}

.post-summary h2 a:hover {
  color: var(--vs-link);
  text-decoration: underline;
}

.post-summary p {
  margin: 6px 0 0;
}

/* The thumbnail on the right, so that every title starts at the left. */
.post-summary.with-thumbnail {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 200px;
  gap: 24px;
  align-items: start;
}

.post-thumbnail img {
  display: block;
  width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
}

.post-thumbnail:hover img {
  border-color: var(--muted);
}

@media (max-width: 640px) {
  .post-summary.with-thumbnail {
    grid-template-columns: minmax(0, 1fr) 96px;
    gap: 14px;
  }
}

.badge {
  display: inline-block;
  margin-left: 6px;
  padding: 0 8px;
  border-radius: 4px;
  background: #e8eaed;
  font-size: 0.75rem;
}

@media (prefers-color-scheme: dark) {
  .badge {
    background: var(--vs-shade);
  }
}

.tag-cloud h2 {
  font-size: 1rem;
  color: var(--vs-muted);
}

.tag-index {
  padding-left: 1.2em;
}

.tag-index .count {
  color: var(--vs-muted);
  font-size: 0.9rem;
}

.post-body {
  margin-top: 20px;
}

/* As much space between list items as the FAQ's loose lists get from their
   paragraphs' margins. */
.post-body li + li {
  margin-top: 1em;
}

/* The text of a post, or of a page with `toc` (pages.ts): what a table of
   contents stays beside. A link to a heading (such as the table's) puts it
   level with the sticky table below. */
.toc-scope :is(h2, h3) {
  scroll-margin-top: 24px;
}

/* A table of contents (site/src/toc.ts): in the margin right of the text,
   sticky; the rail spans the text, so the table stops at the text's end. Only
   where the viewport has room for it beside the main column: its 840px, and
   on each side 20px past its padding, the table's 200px, and 24px to spare,
   plus a scrollbar. Wider viewports widen the table, up to 320px, so long
   headings wrap less. */

.toc-rail {
  display: none;
}

@media (min-width: 1360px) {
  .toc-scope {
    position: relative;
  }

  .toc-rail {
    display: block;
    position: absolute;
    top: 0;
    bottom: 0;
    left: calc(100% + 40px);
    width: clamp(200px, (100vw - var(--measure)) / 2 - 64px, 320px);
  }
}

.toc {
  position: sticky;
  top: 24px;
  max-height: calc(100vh - 48px);
  overflow-y: auto;
  /* A long table scrolls with the wheel, and _js/toc.ts keeps the current
     section in view, but shows no scrollbar beside the text. */
  scrollbar-width: none;
  font-size: 0.85rem;
  line-height: 1.4;
  overflow-wrap: break-word;
}

.toc-title {
  margin: 0 0 8px;
  font-weight: 600;
}

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

.toc > ol {
  border-left: 1px solid var(--vs-border);
}

/* The current section's bar (_js/toc.ts) covers the list's border. */
.toc a {
  display: block;
  margin-left: -1px;
  padding: 3px 0 3px 12px;
  border-left: 2px solid transparent;
  color: var(--vs-muted);
  text-decoration: none;
}

.toc ol ol a {
  padding-left: 24px;
}

.toc a:hover {
  color: var(--vs-text);
}

.toc a[aria-current] {
  border-left-color: var(--vs-accent);
  color: var(--vs-text);
}

/* Home page */

.home-links {
  margin: 0 0 40px;
  padding: 0;
  list-style: none;
}

.home-links li {
  padding: 16px 0;
  border-bottom: 1px solid var(--vs-border);
}

.home-links li:first-child {
  padding-top: 0;
}

.home-links h2 {
  margin: 0;
  font-size: 1.3rem;
  line-height: 1.3;
  border: none;
}

.home-links h2 a {
  color: inherit;
  text-decoration: none;
}

.home-links h2 a:hover {
  color: var(--vs-link);
  text-decoration: underline;
}

.home-links p {
  margin: 4px 0 0;
  color: var(--vs-muted);
}

/* An entry that is one link as a whole (class home-card): its heading's link
   covers the entry, so a click anywhere in it follows the link, and hovering
   or focusing it marks the heading. Entries with links of their own (such as
   the FAQ's languages) can't be one. */
.home-card {
  position: relative;
}

.home-card h2 a::after {
  content: "";
  position: absolute;
  inset: 0;
}

.home-card h2 a:focus-visible {
  outline: none;
  color: var(--vs-link);
  text-decoration: underline;
}

.home-card:has(h2 a:focus-visible) {
  outline: 2px solid var(--vs-link);
  outline-offset: 4px;
  border-radius: 4px;
}

.home-section {
  margin: 0;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--vs-border);
  color: var(--vs-muted);
  font-size: 0.95rem;
  font-weight: 600;
}

/* The newest posts (recent-posts.html, on the home page). */

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

.recent-posts li {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: 2px 16px;
  padding: 10px 0;
  border-bottom: 1px solid var(--vs-border);
}

.recent-posts time {
  color: var(--vs-muted);
  font-size: 0.9rem;
  white-space: nowrap;
}

.recent-posts-more {
  margin: 10px 0 0;
  font-size: 0.9rem;
  font-weight: 600;
  text-align: right;
}

.recent-posts-more a {
  text-decoration: none;
}

.recent-posts-more a:hover {
  text-decoration: underline;
}

/* Post content (more in minimal.css) */

/* A notice to read first (the FAQ's disclaimer): a title with a warning
   sign, a bold lead, a tight list, and fine print. Its first and last
   elements don't add their margins to its padding. */
.notice {
  margin: 16px 0 28px;
  padding: 16px 20px;
  background: var(--vs-notice-bg);
  border: 1px solid var(--vs-notice-border);
  border-left: 4px solid var(--vs-notice-accent);
  border-radius: 8px;
  font-size: 0.95rem;
  line-height: 1.55;
}

.notice p {
  margin: 0.6em 0;
}

.notice > :first-child {
  margin-top: 0;
}

.notice > :last-child {
  margin-bottom: 0;
}

.notice-title {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--vs-notice-title);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.notice-title::before {
  content: "";
  flex: none;
  width: 18px;
  height: 18px;
  background: var(--vs-notice-accent);
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M12 2 1 21h22L12 2zm-1 7h2v6h-2V9zm0 8h2v2h-2v-2z'/%3E%3C/svg%3E")
    center / contain no-repeat;
}

.notice ul {
  margin: 0.6em 0;
  padding-left: 1.3em;
}

.notice li + li {
  margin-top: 0.3em;
}

.notice-fine {
  padding-top: 0.6em;
  border-top: 1px solid var(--vs-notice-border);
  color: var(--vs-muted);
  font-size: 0.82rem;
  line-height: 1.5;
}

table {
  border-collapse: collapse;
  display: block;
  overflow-x: auto;
}

th,
td {
  border: 1px solid var(--vs-border);
  padding: 4px 8px;
}

/* Figures (site/src/markdown.ts): an image, centered, linked to itself,
   and its caption. On phones, images take the column's width, whatever width
   the page gave them. */

figure {
  margin: 1.5em 0;
  text-align: center;
}

figure img {
  vertical-align: middle;
}

figcaption {
  margin-top: 8px;
  color: var(--vs-muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

a.lightbox {
  cursor: zoom-in;
}

a.lightbox:focus-visible {
  outline: none;
}

a.lightbox:focus-visible img {
  outline: 2px solid var(--vs-link);
  outline-offset: 2px;
}

@media (max-width: 640px) {
  figure img {
    width: 100% !important;
  }
}

/* The lightbox (_js/lightbox.ts): the image as large as the viewport allows,
   over a dark backdrop, the same in any color scheme. */

html:has(.lightbox-dialog[open]) {
  overflow: hidden;
}

.lightbox-dialog {
  width: 100vw;
  max-width: none;
  height: 100vh;
  height: 100dvh;
  max-height: none;
  margin: 0;
  padding: 16px;
  border: none;
  background: transparent;
  cursor: zoom-out;
}

.lightbox-dialog[open] {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.lightbox-dialog::backdrop {
  background: rgb(0 0 0 / 0.92);
}

.lightbox-dialog img {
  min-height: 0;
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
  background: #fff;
}

.lightbox-caption {
  flex-shrink: 0;
  max-width: 70ch;
  margin: 0;
  color: #eee;
  font-size: 0.95rem;
  line-height: 1.45;
  text-align: center;
}

.lightbox-caption a {
  color: inherit;
}

.lightbox-close {
  position: fixed;
  top: 12px;
  right: 12px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: none;
  border-radius: 50%;
  background: rgb(255 255 255 / 0.15);
  color: #fff;
  font: inherit;
  font-size: 28px;
  line-height: 1;
  cursor: pointer;
}

.lightbox-close:hover {
  background: rgb(255 255 255 / 0.3);
}

.lightbox-close:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 2px;
}

/* Footer */

.site-footer {
  border-top: 1px solid var(--vs-border);
  background: var(--vs-surface);
  color: var(--vs-muted);
  font-size: 0.875rem;
}

.site-footer > * {
  max-width: var(--measure);
  margin-left: auto;
  margin-right: auto;
  padding: 0 20px;
}

.site-footer p:first-child {
  margin-top: 16px;
  font-style: italic;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
}

.footer-links a {
  color: var(--vs-muted);
}

/* minimal.css puts it top left, over the logo. */
.env-indicator {
  top: auto;
  bottom: 15px;
}