/* auto + lazy load */
img { max-width: 100%; height: auto; }

/* ---------- Beautify TOC ---------- */
.toc {
  margin: 1.5rem 0;
  padding: 1rem;
  background-color: #f9f9f9;
  border-left: 4px solid #ccc;
  border-radius: 6px;
  font-size: 0.95rem;
}

.toc summary {
  font-weight: bold;
  margin-bottom: 0.5rem;
  cursor: pointer;
}

.toc ul {
  padding-left: 1.2rem;
  margin: 0;
}

.toc li {
  margin: 0.3rem 0;
}

/* ---------- Beautify Related Posts ---------- */
.related-posts {
  margin-top: 3rem;
}

.related-post-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.related-post-card {
  display: block;
  padding: 1rem;
  border-radius: 10px;
  text-decoration: none;
  color: inherit;
  background: #ffffff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  transition: transform .2s ease, box-shadow .2s ease;
}

.related-post-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(0,0,0,0.12);
}

.related-post-card h4 {
  margin: 0 0 .4rem;
  font-size: 1.1rem;
  color: #333;
}

.related-post-card p {
  margin: 0;
  font-size: .9rem;
  color: #555;
}

/*----------------- Beautify blog index page ------------------*/
.blog-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-top: 2rem;
}

.blog-card {
  padding: 1.2rem 1.5rem;
  border-radius: 10px;
  background: #fafafa;
  box-shadow: 0 1px 6px rgba(0,0,0,0.04);
  transition: box-shadow 0.2s ease;
}

.blog-card:hover {
  box-shadow: 0 4px 14px rgba(0,0,0,0.08);
}

.blog-title {
  font-size: 1.25rem;
  font-weight: bold;
  color: #222;
  text-decoration: none;
}

.blog-title:hover {
  text-decoration: underline;
}

.blog-meta {
  font-size: 0.85rem;
  color: #777;
  margin-top: 0.3rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tags a {
  color: #3b82f6;
  text-decoration: none;
}

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

.blog-summary {
  margin-top: 0.8rem;
  font-size: 0.95rem;
  color: #444;
  line-height: 1.5;
}

.blog-cover {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 1rem;
}

.pagination {
  margin: 2rem 0;
  text-align: center;
  font-size: 0.95rem;
}

.pagination a {
  margin: 0 1rem;
  color: #007acc;
  text-decoration: none;
  font-weight: bold;
}

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

/* ---------- Base theme variables ---------- */
:root {
  --background-color: #f5f6f8;
  --heading-color: #1c232d;
  --text-color: #2a313a;
  --link-color: #2f5f85;
  --visited-color: #4a637a;
  --code-background-color: #edf1f5;
  --code-color: #2a313a;
  --code-border-color: #dbe2ea;
  --blockquote-color: #3b4756;

  --surface-color: #fafbfc;
  --border-color: #d8e0e8;
  --muted-color: #5a6a7b;
  --toc-background-color: #eef2f6;
}

@media (prefers-color-scheme: dark) {
  :root {
    --background-color: #0f141a;
    --heading-color: #e3e8ef;
    --text-color: #cfd6de;
    --link-color: #7fa6c9;
    --visited-color: #8c9fb6;
    --code-background-color: #151b22;
    --code-color: #cfd6de;
    --code-border-color: #222a33;
    --blockquote-color: #b8c4d2;

    --surface-color: #131a22;
    --border-color: #232b35;
    --muted-color: #a1adba;
    --toc-background-color: #161d25;
  }
}

:root[data-theme="light"] {
  --background-color: #f5f6f8;
  --heading-color: #1c232d;
  --text-color: #2a313a;
  --link-color: #2f5f85;
  --visited-color: #4a637a;
  --code-background-color: #edf1f5;
  --code-color: #2a313a;
  --code-border-color: #dbe2ea;
  --blockquote-color: #3b4756;

  --surface-color: #fafbfc;
  --border-color: #d8e0e8;
  --muted-color: #5a6a7b;
  --toc-background-color: #eef2f6;
}

:root[data-theme="dark"] {
  --background-color: #0f141a;
  --heading-color: #e3e8ef;
  --text-color: #cfd6de;
  --link-color: #7fa6c9;
  --visited-color: #8c9fb6;
  --code-background-color: #151b22;
  --code-color: #cfd6de;
  --code-border-color: #222a33;
  --blockquote-color: #b8c4d2;

  --surface-color: #131a22;
  --border-color: #232b35;
  --muted-color: #a1adba;
  --toc-background-color: #161d25;
}

/* ---------- Global baseline ---------- */
body,
main,
header,
footer {
  background-color: var(--background-color);
  color: var(--text-color);
}

body {
  font-family: "Source Serif 4", Georgia, "Times New Roman", serif;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: "IBM Plex Sans", "Helvetica Neue", Arial, sans-serif;
  letter-spacing: -0.01em;
}

header {
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

main {
  padding-top: 1.25rem;
}

.site-header {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.6rem;
}

.site-nav-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  width: 100%;
  gap: 0.8rem;
  justify-content: space-between;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  flex: 1 1 auto;
  gap: 0.6rem;
  align-items: center;
}

.site-actions {
  margin-left: auto;
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  height: 2rem;
  width: 2rem;
  padding: 0;
  border: 1px solid var(--border-color);
  border-radius: 999px;
  background: var(--surface-color);
  color: var(--muted-color);
  text-decoration: none;
  transition: border-color 140ms ease, color 140ms ease, background-color 140ms ease;
}

.lang-toggle:hover {
  border-color: var(--link-color);
  color: var(--link-color);
  text-decoration: none;
}

.lang-toggle svg {
  display: block;
}

.lang-toggle:focus-visible {
  outline: 2px solid var(--link-color);
  outline-offset: 2px;
}

.theme-toggle {
  border: 1px solid var(--border-color);
  background: var(--surface-color);
  color: var(--muted-color);
  border-radius: 999px;
  width: 2rem;
  height: 2rem;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0;
  line-height: 0;
}

.theme-toggle:hover {
  border-color: var(--link-color);
  color: var(--link-color);
}

.theme-toggle svg {
  display: block;
}

.theme-toggle-label {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- Accessibility ---------- */
.theme-toggle:focus-visible {
  outline: 2px solid var(--link-color);
  outline-offset: 2px;
}

/* ---------- Giscus ---------- */
.giscus-container {
  min-height: clamp(320px, 45vh, 520px);
  margin-top: 2rem;
}

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

hr {
  border-color: var(--border-color);
}

/* ---------- Blog index cards ---------- */
.blog-card {
  background: var(--surface-color);
  border: 1px solid var(--border-color);
  box-shadow: 0 2px 10px rgba(12, 24, 36, 0.06);
}

.blog-card:hover {
  box-shadow: 0 10px 24px rgba(12, 24, 36, 0.14);
}

.blog-title {
  color: var(--heading-color);
}

.blog-meta,
.blog-summary {
  color: var(--muted-color);
}

/* ---------- TOC ---------- */
.toc {
  background-color: var(--toc-background-color);
  border-left-color: var(--border-color);
  box-shadow: 0 4px 16px rgba(12, 24, 36, 0.08);
}

.toc summary {
  color: var(--heading-color);
}

/* ---------- Related posts ---------- */
.related-post-card {
  background: var(--surface-color);
  border: 1px solid var(--border-color);
  box-shadow: 0 2px 10px rgba(12, 24, 36, 0.06);
}

.related-post-card h4 {
  color: var(--heading-color);
}

.related-post-card p {
  color: var(--muted-color);
}

/* ---------- Blockquote ---------- */
blockquote {
  margin: 1.2rem 0;
  padding: 0.6rem 1rem;
  border-left: 4px solid var(--border-color);
  background: var(--toc-background-color);
  color: var(--blockquote-color);
}

/* ---------- Callouts ---------- */
.callout {
  margin: 1.2rem 0;
  padding: 0.85rem 1rem;
  border: 1px solid var(--border-color);
  border-left-width: 4px;
  border-radius: 8px;
  background: var(--surface-color);
}

.callout-title {
  margin-bottom: 0.45rem;
  font-family: "IBM Plex Sans", "Helvetica Neue", Arial, sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--heading-color);
}

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

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

.callout-note {
  border-left-color: #4f7aa3;
  background: color-mix(in srgb, var(--surface-color) 88%, #4f7aa3 12%);
}

.callout-tip {
  border-left-color: #4d8762;
  background: color-mix(in srgb, var(--surface-color) 88%, #4d8762 12%);
}

.callout-warning,
.callout-caution {
  border-left-color: #b57933;
  background: color-mix(in srgb, var(--surface-color) 88%, #b57933 12%);
}

.callout-important {
  border-left-color: #8b5fbf;
  background: color-mix(in srgb, var(--surface-color) 88%, #8b5fbf 12%);
}

/* ---------- Code blocks ---------- */
pre,
code {
  background-color: var(--code-background-color);
  color: var(--code-color);
}

.highlight {
  overflow-x: auto;
}

.highlight > .chroma {
  background-color: var(--code-background-color);
  border: 1px solid var(--code-border-color);
  border-radius: 6px;
}

.chroma {
  background-color: transparent !important;
  border: 0;
  border-radius: 0;
}

.chroma .lntable {
  border-spacing: 0;
  width: max-content;
  min-width: 100%;
  table-layout: fixed;
}

.chroma .lntd {
  padding: 0;
  vertical-align: top;
}

.chroma pre.chroma {
  margin: 0;
  padding: 0.6rem 0.9rem;
  line-height: 1.5;
  font-size: 0.95rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

.chroma .lntd:first-child {
  width: 3.2ch;
}

.chroma .lntd:first-child pre.chroma {
  padding-right: 0.6rem;
  padding-left: 0.7rem;
  text-align: right;
  user-select: none;
}

.chroma .lnt {
  display: block;
  line-height: 1.5;
}

.chroma .line {
  display: block;
  line-height: 1.5;
}

.chroma .lnt,
.chroma .ln {
  color: var(--muted-color) !important;
}

/* ---------- Images ---------- */
content img {
  border-radius: 6px;
}

.post-figure {
  width: 100%;
  max-width: min(100%, var(--figure-width, 46rem));
  margin: 1.5rem auto;
}

.post-figure img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  box-shadow: 0 10px 24px rgba(12, 24, 36, 0.08);
}

.post-figure figcaption {
  margin-top: 0.65rem;
  font-size: 0.92rem;
  line-height: 1.55;
  color: var(--muted-color);
  text-align: center;
}

.post-figure.narrow {
  max-width: min(100%, 34rem);
}

.post-figure.wide {
  max-width: min(100%, 56rem);
}

.post-figure.full-bleed {
  max-width: min(100vw - 2.5rem, 68rem);
}

.post-figure-link {
  display: block;
}

.figure-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.figure-grid .post-figure {
  margin: 0;
  max-width: none;
}

.details-block {
  margin: 1.35rem 0;
  border: 1px solid var(--border-color);
  border-radius: 10px;
  background: var(--surface-color);
  box-shadow: 0 6px 18px rgba(12, 24, 36, 0.05);
  overflow: hidden;
}

.details-block summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1rem;
  cursor: pointer;
  list-style: none;
  font-family: "IBM Plex Sans", "Helvetica Neue", Arial, sans-serif;
  font-size: 0.96rem;
  font-weight: 600;
  color: var(--heading-color);
}

.details-block summary::-webkit-details-marker {
  display: none;
}

.details-block summary::after {
  content: "+";
  color: var(--muted-color);
  font-size: 1.1rem;
  line-height: 1;
}

.details-block[open] summary {
  border-bottom: 1px solid var(--border-color);
}

.details-block[open] summary::after {
  content: "−";
}

.details-content {
  padding: 0.9rem 1rem 1rem;
}

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

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

.mermaid-diagram {
  margin: 1.5rem 0;
  padding: 1rem;
  border: 1px solid var(--border-color);
  border-radius: 10px;
  background: var(--surface-color);
  overflow-x: auto;
}

.mermaid-diagram pre {
  margin: 0;
  background: transparent;
  border: 0;
  padding: 0;
}

.mermaid-diagram svg {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto;
}

.katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 0.2rem 0;
}

.footnote-ref {
  margin-left: 0.08rem;
  font-family: "IBM Plex Sans", "Helvetica Neue", Arial, sans-serif;
  font-size: 0.78em;
  font-weight: 600;
  text-decoration: none;
}

.footnote-backref {
  margin-left: 0.35rem;
  color: var(--muted-color);
  text-decoration: none;
}

.footnotes {
  margin-top: 2.4rem;
  padding-top: 1rem;
  border-top: 1px dashed var(--border-color);
  color: var(--muted-color);
  font-size: 0.94rem;
}

.footnotes hr {
  display: none;
}

.footnotes ol {
  margin: 0.75rem 0 0;
  padding-left: 1.25rem;
}

.footnotes li {
  margin: 0.55rem 0;
  padding-left: 0.15rem;
}

.footnotes p {
  margin: 0.35rem 0;
}

.chroma {
  background-color: var(--code-background-color) !important;
  color: var(--code-color);
  border: 1px solid var(--code-border-color);
  border-radius: 6px;
}

.chroma .lnt,
.chroma .ln {
  color: var(--muted-color) !important;
}

/* ---------- Pagination ---------- */
.pagination a {
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
}
/* ---------- Post meta ---------- */
.post-meta {
  margin: 0.2rem 0 1rem;
  color: var(--muted-color);
  font-size: 0.95rem;
}

.post-tags {
  margin-top: 1.25rem;
}

.post-tags a {
  display: inline-block;
  padding: 0.1rem 0.45rem;
  margin: 0.15rem 0.3rem 0.15rem 0;
  border: 1px solid var(--border-color);
  border-radius: 999px;
  color: var(--muted-color);
  background: var(--surface-color);
}

.post-tags a:hover {
  color: var(--link-color);
  border-color: var(--link-color);
  text-decoration: none;
}