:root {
  color-scheme: light dark;
  --bg: #f8fafc;
  --text: #17202b;
  --body: #232d3a;
  --muted: #5c6674;
  --line: #d9e0e8;
  --link: #1d4ed8;
  --link-hover: #1e40af;
  --code-bg: #edf2f7;
  --code-text: #223041;
  --syntax-keyword: #9f1239;
  --syntax-string: #92400e;
  --syntax-number: #166534;
  --syntax-built-in: #0f766e;
  --syntax-attr: #854d0e;
  --syntax-comment: #64748b;
  --syntax-punctuation: #475569;
  --alert-note: #2563eb;
  --alert-tip: #15803d;
  --alert-important: #7c3aed;
  --alert-warning: #b45309;
  --alert-caution: #dc2626;
  --icon-external-link: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M15 3h6v6'/%3E%3Cpath d='M10 14 21 3'/%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3C/svg%3E");
  --radius: 8px;
  --measure: 61rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f141b;
    --text: #e7edf5;
    --body: #c9d3df;
    --muted: #aab4c0;
    --line: #2a3442;
    --link: #93c5fd;
    --link-hover: #bfdbfe;
    --code-bg: #1c2530;
    --code-text: #eef4fb;
    --syntax-keyword: #fda4af;
    --syntax-string: #fbbf24;
    --syntax-number: #86efac;
    --syntax-built-in: #67e8f9;
    --syntax-attr: #fde68a;
    --syntax-comment: #94a3b8;
    --syntax-punctuation: #cbd5e1;
    --alert-note: #60a5fa;
    --alert-tip: #4ade80;
    --alert-important: #c4b5fd;
    --alert-warning: #fbbf24;
    --alert-caution: #f87171;
  }
}

* {
  box-sizing: border-box;
}

html {
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
}

a {
  color: var(--link);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

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

.prose a[target="_blank"]::after,
.page-actions a[target="_blank"]::after {
  content: "";
  display: inline-block;
  width: 0.72em;
  height: 0.72em;
  margin-left: 0.25em;
  vertical-align: 0.02em;
  background: currentColor;
  opacity: 0.72;
  -webkit-mask: var(--icon-external-link) center / contain no-repeat;
  mask: var(--icon-external-link) center / contain no-repeat;
}

::selection {
  background: color-mix(in srgb, var(--link) 28%, transparent);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  border: 0;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  overflow: hidden;
  white-space: nowrap;
}

.shell {
  width: min(var(--measure), calc(100% - 2rem));
  margin: 0 auto;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: 1rem;
  z-index: 10;
  transform: translateY(-150%);
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  box-shadow: 0 0 0 2px var(--line);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-main {
  padding: 2.5rem 0;
}

.page {
  padding: 0;
}

.prose {
  font-size: 1rem;
  overflow-wrap: break-word;
  word-wrap: break-word;
}

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

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

.prose h1,
.prose h2,
.prose h3,
.prose h4 {
  color: var(--text);
  line-height: 1.2;
  margin: 2rem 0 0.75rem;
}

.prose h1,
.prose h2,
.prose h3 {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.prose h1 {
  font-size: clamp(2rem, 4vw, 2.5rem);
  letter-spacing: 0;
}

.prose h2 {
  padding-top: 0.75rem;
  border-top: 1px solid var(--line);
  font-size: clamp(1.5rem, 3vw, 1.9rem);
}

.prose h3 {
  font-size: 1.2rem;
}

.prose h4 {
  font-size: 1rem;
}

.prose h2[id],
.prose h3[id],
.prose h4[id] {
  position: relative;
  scroll-margin-top: 1rem;
}

.heading-anchor {
  display: inline-flex;
  align-items: center;
  vertical-align: 0.08em;
  margin-left: 0.45rem;
  color: var(--muted);
  font-size: 0.8em;
  font-weight: 500;
  opacity: 0;
  text-decoration: none;
}

.prose h2:hover .heading-anchor,
.prose h3:hover .heading-anchor,
.prose h4:hover .heading-anchor,
.heading-anchor:focus-visible {
  opacity: 1;
}

.prose p,
.prose li {
  color: var(--body);
}

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

.prose strong,
.prose th {
  color: var(--text);
}

.prose table {
  width: 100%;
  border-spacing: 0;
  border-collapse: collapse;
  margin: 1.5rem 0;
}

.prose th,
.prose td {
  padding: 0.75rem;
  border: 1px solid var(--line);
  text-align: left;
}

.prose th {
  background: var(--code-bg);
}

.prose iframe,
.prose video,
.prose audio {
  display: block;
  max-width: 100%;
  margin: 1.5rem 0;
}

.prose iframe {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  border: 0;
  border-radius: var(--radius);
}

.prose video {
  height: auto;
  color-scheme: light;
  border-radius: var(--radius);
}

.prose audio {
  width: 100%;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  .prose video,
  .prose audio {
    color-scheme: dark;
  }
}

.prose .zp-align-left {
  text-align: left;
}

.prose .zp-align-center {
  text-align: center;
}

.prose .zp-align-right {
  text-align: right;
}

.prose blockquote {
  margin: 1.5rem 0;
  padding: 0.1rem 0 0.1rem 1rem;
  border-left: 4px solid var(--line);
  color: var(--muted);
}

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

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

.prose .contains-task-list {
  padding-left: 0;
  list-style: none;
}

.prose .task-list-item {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
}

.prose .task-list-item-checkbox {
  flex: 0 0 auto;
  width: 1rem;
  height: 1rem;
  margin: 0.32rem 0 0;
  accent-color: var(--link);
}

.zp-alert {
  margin: 1.5rem 0;
  padding: 0.9rem 1rem;
  border: 1px solid color-mix(in srgb, var(--alert-color) 55%, var(--line));
  border-left-width: 4px;
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--alert-color) 10%, transparent);
}

.zp-alert__title {
  margin: 0 0 0.35rem;
  color: var(--alert-color);
  font-weight: 700;
}

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

.zp-alert--note {
  --alert-color: var(--alert-note);
}

.zp-alert--tip {
  --alert-color: var(--alert-tip);
}

.zp-alert--important {
  --alert-color: var(--alert-important);
}

.zp-alert--warning {
  --alert-color: var(--alert-warning);
}

.zp-alert--caution {
  --alert-color: var(--alert-caution);
}

.prose code {
  padding: 0.12rem 0.28rem;
  border-radius: 5px;
  background: var(--code-bg);
  color: var(--code-text);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  font-size: 0.9em;
}

.prose pre {
  position: relative;
  overflow: visible;
  padding: 0;
  border-radius: var(--radius);
  background: var(--code-bg);
  color: var(--code-text);
}

.prose pre code:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

.prose pre code {
  display: block;
  overflow-x: auto;
  padding: 2rem 1.25rem 1.25rem;
  border-radius: var(--radius);
  background: transparent;
  -webkit-overflow-scrolling: touch;
}

.copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.3rem 0.5rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--code-bg);
  color: var(--muted);
  font: inherit;
  font-size: 0.78rem;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.12s ease, color 0.12s ease, border-color 0.12s ease;
}

.prose pre:hover .copy-btn,
.prose pre:focus-within .copy-btn,
.copy-btn:focus-visible {
  opacity: 1;
}

/* Touch devices cannot hover, so keep the control visible there. */
@media (hover: none) {
  .copy-btn {
    opacity: 1;
  }
}

.copy-btn:hover {
  color: var(--text);
  border-color: var(--muted);
}

.copy-btn.is-copied {
  color: var(--alert-tip);
  border-color: color-mix(in srgb, var(--alert-tip) 55%, var(--line));
}

.copy-btn svg {
  flex: 0 0 auto;
}

/* highlight.js output from ZeroPress Markdown rendering */
.prose .hljs-comment,
.prose .hljs-quote,
.prose .hljs-meta {
  color: var(--syntax-comment);
  font-style: italic;
}

.prose .hljs-keyword,
.prose .hljs-literal,
.prose .hljs-selector-tag,
.prose .hljs-section,
.prose .hljs-title {
  color: var(--syntax-keyword);
}

.prose .hljs-string,
.prose .hljs-regexp,
.prose .hljs-template-tag,
.prose .hljs-template-variable {
  color: var(--syntax-string);
}

.prose .hljs-number,
.prose .hljs-symbol,
.prose .hljs-bullet,
.prose .hljs-variable,
.prose .hljs-params {
  color: var(--syntax-number);
}

.prose .hljs-built_in,
.prose .hljs-type,
.prose .hljs-class .hljs-title,
.prose .hljs-title.class_,
.prose .hljs-title.function_ {
  color: var(--syntax-built-in);
}

.prose .hljs-attr,
.prose .hljs-attribute,
.prose .hljs-name,
.prose .hljs-property {
  color: var(--syntax-attr);
}

.prose .hljs-punctuation,
.prose .hljs-operator,
.prose .hljs-tag {
  color: var(--syntax-punctuation);
}

.prose .hljs-emphasis {
  font-style: italic;
}

.prose .hljs-strong {
  font-weight: 700;
}

.prose .hljs-deletion {
  color: var(--alert-caution);
  background: color-mix(in srgb, var(--alert-caution) 14%, transparent);
}

.prose .hljs-addition {
  color: var(--alert-tip);
  background: color-mix(in srgb, var(--alert-tip) 14%, transparent);
}

.prose figure {
  margin: 1.75rem 0;
}

.prose figcaption {
  margin-top: 0.5rem;
  font-size: 0.92rem;
}

.prose hr {
  height: 1px;
  margin: 2rem 0;
  border: 0;
  background: var(--line);
}

.page-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1rem;
  justify-content: flex-end;
  padding-top: 1rem;
  margin-top: 2.5rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.page-actions__updated {
  margin-right: auto;
}

.page-actions__updated time {
  color: var(--body);
}

.page-actions a {
  font-weight: 600;
}

.zp-mermaid {
  margin: 1.5rem 0;
  overflow-x: auto;
  text-align: center;
}

.zp-mermaid svg {
  max-width: 100%;
  height: auto;
}

.zp-mermaid-error {
  outline: 2px solid var(--alert-caution);
  outline-offset: 2px;
}

@media (max-width: 48rem) {
  .prose table {
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
}

@media print {
  /*
   * The plain theme prints natively by design. These overrides only sharpen
   * print legibility without changing the on-screen look:
   *   - darker body text and headings,
   *   - a monochrome code block (syntax colors collapse to a dark ink so code
   *     reads cleanly on paper; on-screen highlighting is left untouched),
   *   - a checkbox that actually shows its checked state (native checkboxes
   *     drop the accent fill and check glyph in print).
   */
  :root {
    --text: #000;
    --body: #1a1a1a;
    --line: #bbb;
    --code-text: #1a1a1a;
    --syntax-keyword: #1a1a1a;
    --syntax-string: #1a1a1a;
    --syntax-number: #1a1a1a;
    --syntax-built-in: #1a1a1a;
    --syntax-attr: #1a1a1a;
    --syntax-comment: #1a1a1a;
    --syntax-punctuation: #1a1a1a;
  }

  /* Keep diff markers monochrome too. */
  .prose .hljs-deletion,
  .prose .hljs-addition {
    color: #1a1a1a;
    background: transparent;
  }

  /*
   * The light code background is dropped in print, so give code blocks a
   * border to keep their bounds visible. Wrap long lines (paper cannot scroll
   * horizontally) and hide the copy button, which is meaningless in print.
   */
  .prose pre {
    border: 1px solid var(--line);
  }

  .prose pre code {
    overflow-x: visible;
    white-space: pre-wrap;
    word-break: break-word;
    padding: 1.25rem;
  }

  .copy-btn {
    display: none !important;
  }

  .prose .task-list-item-checkbox {
    -webkit-appearance: none;
    appearance: none;
    display: inline-grid;
    place-content: center;
    border: 1.5px solid #000;
    border-radius: 3px;
    background: #fff;
    print-color-adjust: exact;
    -webkit-print-color-adjust: exact;
  }

  .prose .task-list-item-checkbox:checked::before {
    content: "";
    width: 0.6rem;
    height: 0.6rem;
    background: #000;
    clip-path: polygon(14% 52%, 36% 74%, 82% 22%, 92% 32%, 37% 88%, 4% 60%);
  }
}