/* Article typography and layout from thinkingmachines.ai/blog/modular-manifolds/. */
@font-face {
  font-family: "Iowan Old Style BT";
  src: url("fonts/iowan-regular.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Iowan Old Style BT";
  src: url("fonts/iowan-italic.woff2") format("woff2");
  font-weight: 400;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Iowan Old Style BT";
  src: url("fonts/iowan-bold.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "GT America";
  src: url("fonts/gt-america-regular.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

:root {
  --text: #282828;
  --muted: #676767;
  --font-serif: "Iowan Old Style BT", Georgia, serif;
  --font-sans: "GT America", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --content-width: 660px;
  --header-height: 54px;
}

* {
  box-sizing: border-box;
}

/* Reset HTML elements only, preserving native MathML spacing. */
:where(body, h1, h2, h3, h4, h5, h6, p, ol, ul, figure, blockquote) {
  margin: 0;
  padding: 0;
}

html {
  overflow-y: scroll;
  scroll-padding-top: calc(var(--header-height) + 1rem);
  scrollbar-width: thin;
  scrollbar-color: var(--muted) white;
}

body {
  padding: var(--header-height) 1rem 0;
  background: white;
  color: var(--text);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.6;
  overflow-wrap: break-word;
}

a {
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: #504945;
  text-decoration: underline;
  text-decoration-color: #6767674d;
  text-underline-offset: 2px;
}

.site-header {
  position: fixed;
  inset: 0 1rem auto;
  z-index: 2;
  height: var(--header-height);
  padding-inline: 0.33rem;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  background: white;
}

.site-header nav {
  display: flex;
  gap: 1.75rem;
  font-family: var(--font-sans);
  font-size: 15px;
  letter-spacing: -0.01em;
}

.site-header nav a {
  color: #3c3836;
}

.post {
  width: 100%;
  max-width: 950px;
  margin-inline: auto;
  padding: 1rem 1rem 4rem;
}

.post-heading {
  text-align: center;
  margin-bottom: 2rem;
}

.post-heading h1 {
  max-width: 710px;
  margin: 1.5rem auto 0;
  font-size: 30px;
  font-weight: 600;
  line-height: 1.4;
  text-wrap: balance;
}

.post-meta {
  margin-top: 1rem;
  color: #6b6866;
  font: 15px/21px var(--font-sans);
  letter-spacing: 0.24px;
}

.post-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, var(--content-width)) minmax(0, 1fr);
  align-items: start;
}

.post-content {
  grid-column: 2;
  width: 100%;
  min-width: 0;
  max-width: var(--content-width);
  margin-inline: auto;
  padding-top: 0.5rem;
}

.post-content p {
  margin-bottom: 1.45rem;
}

.post-content h2,
.post-content h3 {
  font-size: 1.45rem;
  font-weight: 600;
  line-height: 1.4;
  margin: 1.25em 0 0.6em;
}

.post-content h2 {
  font-size: 1.6rem;
}

.post-content h4 {
  font-size: 1.35rem;
  font-weight: 400;
  font-style: italic;
  line-height: 1.4;
  margin: 1.4em 0 0.5em;
}

.post-content h5 {
  font-size: 0.97rem;
  font-weight: 400;
  font-style: italic;
  margin: 1.4em 0 0.7em;
}

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

.post-content a {
  text-decoration: underline;
  text-decoration-color: #6767674d;
}

.post-content :is(ol, ul) {
  margin: 1rem 0 1.2rem 2rem;
}

.post-content ul {
  margin-left: 1.5rem;
  list-style: square;
}

.post-content ol ol {
  list-style-type: lower-alpha;
}

.post-content li {
  margin-bottom: 0.2rem;
}

.post-content li > p:last-child {
  margin-bottom: 0;
}

.post-content code {
  color: #ad2111;
  font-family: SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 0.9em;
  padding-inline: 0.2rem;
}

.post-content pre {
  margin-block: 1.4rem;
  padding: 1rem;
  background: #f3f3f2;
  border-radius: 0.45rem;
  max-width: 100%;
  overflow-x: auto;
}

.post-content pre code {
  color: #6b6866;
  font-size: 13px;
  line-height: 1.4;
}

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

.post-content table {
  display: block;
  max-width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
  margin-block: 1.333rem;
  font-family: var(--font-sans);
}

.post-content :is(th, td) {
  padding: 0.75rem 1rem;
  text-align: left;
  border: 0;
  border-bottom: 1px solid #d9d9d9;
}

.post-content th {
  color: #6b6866;
  font-weight: 400;
}

.toc {
  grid-column: 1;
  justify-self: end;
  position: sticky;
  top: calc(var(--header-height) + 2rem);
  width: calc(210px + 1.3rem);
  max-height: calc(100dvh - var(--header-height) - 3rem);
  margin-right: 34px;
  padding-left: 1.3rem;
  transform: translateY(10px);
  overflow-y: auto;
  scrollbar-width: none;
  font: 13px/1.4 var(--font-sans);
}

.toc ol {
  list-style: none;
}

.toc li {
  margin-bottom: 0.7rem;
}

.toc a[aria-current="location"] {
  color: var(--text);
}

.toc-marker {
  position: absolute;
  top: 0;
  left: calc((1.3rem - 4px) / 2 - 0.05rem);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--text);
  opacity: 0;
  transform: translateY(calc(var(--toc-marker-y, 0px) - 50%));
  transition: transform 0.28s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.16s;
}

.toc:has([aria-current]) .toc-marker {
  opacity: 1;
}

.post-footer {
  display: flex;
  justify-content: space-between;
  max-width: var(--content-width);
  margin: 3.5rem auto 0;
  font: 15px/1.4 var(--font-sans);
}

@media (max-width: 1279px) {
  .post {
    max-width: 100%;
    padding-inline: 1.3rem;
  }
  .post-body { display: block; }
  .toc { display: none; }
}

@media (max-width: 768px) {
  :root { --header-height: 50px; }
  body { padding-inline: 0.33rem; }
  .site-header {
    inset-inline: 0;
    padding-inline: 1rem;
  }
  .site-header nav { gap: 1.5rem; }
}

@media (prefers-reduced-motion: reduce) {
  a, .toc-marker { transition: none; }
}