:root{
  --max-main: 66ch;
  --max-rail: 22ch;

  /* Vertical rhythm */
  --gap-p: clamp(0.75rem, 1.2vw, 1.05rem);
  --gap-block: clamp(1.25rem, 2vw, 2rem);
  --gap-section: clamp(2.25rem, 3.2vw, 3.5rem);

  /* Typography */
  --font-body: "Source Serif 4","IBM Plex Serif","Literata",Georgia,serif;
  --font-sans: "Inter","IBM Plex Sans",system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;
  --font-mono: "IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --fs-body: clamp(1.02rem, 0.4vw + 1rem, 1.15rem);
  --lh-body: 1.65;
  --fs-meta: 0.85rem;
  --ls-meta: 0.02em;

  /* Links */
  --underline-offset: 0.18em;
  --underline-thickness: 0.06em;

  /* Focus */
  --focus-width: 2px;
  --focus-offset: 2px;

  /* Texture */
  --texture-opacity: 0.025;
}

html[data-theme="light"]{
  --bg: #F4F1EA;
  --text: #151515;
  --secondary: #3F3F3F;
  --meta: #6B6B6B;
  --border: #D8D2C8;
  --code-bg: #EEE9DF;
  --accent: #1F4AA8;
  --selection: rgba(31,74,168,0.14);
  --texture-opacity: 0.02;
}

html[data-theme="dark"]{
  --bg: #0F1115;
  --text: #E7E4DC;
  --secondary: #C8C1B4;
  --meta: #9A948A;
  --border: #2A2E36;
  --code-bg: #151923;
  --accent: #7AA2F7;
  --selection: rgba(122,162,247,0.20);
  --texture-opacity: 0.03;
}

*{ box-sizing: border-box; }

html{
  font-size: 100%;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  hyphens: auto;
}

body{
  margin: 0;
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--text);
  background: var(--bg);
  text-wrap: pretty;
}

:where(h1,h2,h3,h4,h5,h6){
  text-wrap: balance;
}

/* Editorial texture */
body::before{
  content:"";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: var(--texture-opacity);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='220' height='220'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='220' height='220' filter='url(%23n)' opacity='1'/%3E%3C/svg%3E");
  background-size: 900px 900px;
  mix-blend-mode: soft-light;
  z-index: 0;
}
@media (forced-colors: active), (prefers-contrast: more){
  body::before{ display: none; }
}

::selection{ background: var(--selection); }

a{
  color: var(--accent);
  text-decoration: none;
  text-decoration-thickness: var(--underline-thickness);
  text-underline-offset: var(--underline-offset);
}
a:hover, a:focus-visible{
  text-decoration: underline;
}

button{
  font: inherit;
  color: inherit;
}

.skip-link{
  position: absolute;
  left: 0.75rem;
  top: 0.75rem;
  padding: 0.5rem 0.75rem;
  font-family: var(--font-sans);
  font-size: var(--fs-meta);
  letter-spacing: var(--ls-meta);
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  transform: translateY(-200%);
}
.skip-link:focus{ transform: translateY(0); }

:focus-visible{
  outline: var(--focus-width) solid var(--accent);
  outline-offset: var(--focus-offset);
  border-radius: 2px;
}

header{
  position: sticky;
  top: 0;
  z-index: 5;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--border);
}
.topbar{
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.95rem 1.25rem;
  font-family: var(--font-sans);
  font-size: var(--fs-meta);
  letter-spacing: var(--ls-meta);
  color: var(--meta);
}
.brand{ color: var(--meta); text-decoration: none; }
nav[aria-label="Primary"]{
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}
nav a{ color: var(--meta); }
nav a[aria-current="page"]{ color: var(--text); }

.controls{
  display: flex;
  align-items: center;
  gap: 0.85rem;
  white-space: nowrap;
}
.lang a{ color: var(--meta); }
.lang a[aria-current="true"]{ color: var(--text); }
.theme{
  all: unset;
  cursor: pointer;
  color: var(--meta);
  font-size: 1rem;
  line-height: 1;
  padding: 0.4rem;
}
.theme:hover{ color: var(--text); }

.shell{
  display: grid;
  grid-template-columns: minmax(1.25rem, 1fr) minmax(0, var(--max-main)) minmax(0, var(--max-rail)) minmax(1.25rem, 1fr);
  column-gap: 2rem;
  padding: 2.25rem 0;
  align-items: start;
  position: relative;
  z-index: 1;
}
.shell.no-rail{
  grid-template-columns: minmax(1.25rem,1fr) minmax(0, var(--max-main)) minmax(1.25rem,1fr);
}
.shell.no-rail > main{ grid-column: 2; }
.shell.no-rail > aside{ display: none; }

main{
  grid-column: 2;
  min-width: 0;
}

aside{
  grid-column: 3;
  position: sticky;
  top: 4rem;
  align-self: start;
  border-left: 1px solid var(--border);
  padding-left: 1rem;
  font-family: var(--font-sans);
  font-size: var(--fs-meta);
  letter-spacing: var(--ls-meta);
  color: var(--meta);
}
aside .label{
  color: var(--meta);
  margin-bottom: 0.75rem;
}
aside a{ color: var(--meta); }
aside a[aria-current="true"]{ color: var(--text); }

.outline-mobile{
  display: none;
  margin: 0 0 var(--gap-block) 0;
  font-family: var(--font-sans);
  font-size: var(--fs-meta);
  letter-spacing: var(--ls-meta);
  color: var(--meta);
}
.outline-mobile details{
  border: 1px solid var(--border);
  padding: 0.6rem 0.75rem;
}
.outline-mobile summary{
  cursor: pointer;
  color: var(--meta);
  list-style: none;
}
.outline-mobile summary::-webkit-details-marker{ display:none; }

@media (max-width: 860px){
  .shell{
    grid-template-columns: 1rem minmax(0, var(--max-main)) 1rem;
    column-gap: 0;
  }
  aside{ display: none; }
  main{ grid-column: 2; }
  .outline-mobile{ display: block; grid-column: 2; }
}

article > * + *{ margin-top: var(--gap-p); }
article > h2{ margin-top: var(--gap-section); }
article > .block{ margin-top: var(--gap-block); }

h1,h2{
  font-weight: 600;
  line-height: 1.15;
  margin: 0;
}
h1{ font-size: clamp(1.7rem, 1.1vw + 1.4rem, 2rem); }
h2{ font-size: clamp(1.15rem, 0.6vw + 1.05rem, 1.35rem); }

.meta-line{
  font-family: var(--font-sans);
  font-size: var(--fs-meta);
  letter-spacing: var(--ls-meta);
  color: var(--meta);
  margin-top: 0.35rem;
}

article{ counter-reset: sec; }
h2{
  position: relative;
  counter-increment: sec;
}
h2::before{
  content: counter(sec, decimal-leading-zero);
  position: absolute;
  left: -3.2rem;
  top: 0.2rem;
  font-family: var(--font-sans);
  font-size: var(--fs-meta);
  letter-spacing: var(--ls-meta);
  color: var(--meta);
}
@media (max-width: 860px){
  h2::before{ display: none; }
}

.axiom{
  margin-top: var(--gap-block);
  padding: 1rem 1.1rem;
  border-left: 2px solid var(--border);
  background: color-mix(in srgb, var(--code-bg) 80%, transparent);
  font-family: var(--font-mono);
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--text);
}

ul,ol{
  margin: 0;
  padding-left: 1.1rem;
}

blockquote{
  margin: 0;
  padding-left: 1rem;
  border-left: 2px solid var(--border);
  color: var(--secondary);
}

.callout{
  font-family: var(--font-sans);
  color: var(--secondary);
}

footer{
  padding: 2.5rem 1.25rem;
  font-family: var(--font-sans);
  font-size: var(--fs-meta);
  letter-spacing: var(--ls-meta);
  color: var(--meta);
  border-top: 1px solid var(--border);
}
footer a{ color: var(--meta); }
footer a:hover{ color: var(--text); text-decoration: none; }

:where(h2, h3, h4){ scroll-margin-top: 5rem; }

@media (prefers-reduced-motion: reduce){
  *, *::before, *::after{ animation-duration: 0s !important; transition-duration: 0s !important; }
}

@media print{
  body::before{ display:none; }
  header, footer, .outline-mobile, aside{ display:none !important; }
  body{ color: #000; background: #fff; }
  a{ color: inherit; text-decoration: none; }
}