/* ==========================================================================
   Layout and typography for all pages. Values come from tokens.css.
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: var(--leading);
  text-rendering: optimizeLegibility;
}

main { flex: 1; }

.wrap {
  width: 100%;
  max-width: calc(var(--measure) + 2 * var(--gutter));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* --- Header band ------------------------------------------------------- */

.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--rule);
}
.site-header__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2) var(--space-4);
  padding-block: var(--space-4);
}
.site-name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: 1.3rem;
  line-height: var(--leading-tight);
  color: var(--heading);
  text-decoration: none;
}
.site-name:hover { color: var(--heading); }

.site-header__end {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-3);
  font-family: var(--font-heading);
}

.theme-toggle {
  display: inline-grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  padding: 0;
  border: 1px solid var(--rule);
  border-radius: 50%;
  background: transparent;
  color: var(--text);
  cursor: pointer;
}
.theme-toggle:hover { color: var(--link); border-color: currentColor; }
.theme-toggle[aria-pressed="true"] svg { transform: rotate(180deg); }

.nav {
  display: flex;
  flex-wrap: wrap;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 0.95rem;
}
.nav li + li { margin-top: 0; }
.nav li + li::before {
  content: "/";
  content: "/" / "";
  margin-inline: 0.55em;
  color: var(--muted);
}
.nav a {
  color: var(--text);
  text-decoration: none;
}
.nav a:hover { color: var(--link); text-decoration: underline; }
.nav a[aria-current] {
  color: var(--heading);
  font-weight: 600;
}

main.wrap { padding-block: var(--space-5) var(--space-6); }

/* --- Typography --------------------------------------------------------- */

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-tight);
  color: var(--heading);
  margin: var(--space-5) 0 var(--space-3);
}
h1 { font-size: var(--text-h1); margin-top: 0; letter-spacing: -0.01em; }
h2 {
  font-size: var(--text-h2);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--rule);
}
h3 { font-size: var(--text-h3); margin-top: var(--space-4); }
h4 { font-size: 1rem; }

p, ul, ol, dl, blockquote, pre, table, figure { margin: 0 0 var(--space-3); }
ul, ol { padding-left: 1.4em; }
li + li { margin-top: var(--space-2); }

a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}
a:hover { color: var(--link-hover); text-decoration-thickness: 2px; }

strong, b { font-weight: 700; }
small, .meta { font-size: var(--text-small); color: var(--muted); }

hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: var(--space-5) 0;
}

/* Pull-quote style: accent bar, large bold heading type. */
blockquote {
  margin: var(--space-5) 0 var(--space-5) calc(-1 * var(--space-4));
  padding: var(--space-1) 0 var(--space-1) calc(var(--space-4) - 4px);
  border-left: 4px solid var(--accent);
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: var(--weight-heading);
  line-height: 1.35;
  color: var(--heading);
}
blockquote > :last-child { margin-bottom: 0; }
@media (max-width: 40rem) {
  blockquote { margin-left: 0; padding-left: var(--space-3); font-size: 1.25rem; }
}

code, kbd, pre { font-family: var(--font-mono); font-size: 0.9em; }
code {
  padding: 0.1em 0.3em;
  background: var(--surface);
  border-radius: var(--radius);
}
pre {
  padding: var(--space-3);
  overflow-x: auto;
  background: var(--surface);
  border-radius: var(--radius);
  line-height: 1.5;
}
pre code { padding: 0; background: none; }

table { width: 100%; border-collapse: collapse; font-size: 0.95em; }
th, td { padding: var(--space-2); border-bottom: 1px solid var(--rule); text-align: left; vertical-align: top; }
th { color: var(--heading); }

/* --- Images ------------------------------------------------------------- */

img, video { max-width: 100%; height: auto; }
figure img { display: block; }
figcaption { margin-top: var(--space-2); font-size: var(--text-small); color: var(--muted); }

/* --- Columns ------------------------------------------------------------
   <div class="columns" markdown="1"> … </div>
   Each direct child is one column. Variants:
     .three          three equal columns
     .narrow-first   narrow first column (photo/sidebar), wide second
   All stack into one column on small screens.
   ------------------------------------------------------------------------ */

.columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4) var(--space-5);
  align-items: start;
  margin-bottom: var(--space-3);
}
.columns.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.columns.narrow-first { grid-template-columns: var(--portrait-width) minmax(0, 1fr); }
.columns > * { margin-top: 0; }
.columns > * > :last-child { margin-bottom: 0; }
.columns > p:has(> img:only-child) { margin: 0; }
.columns img { display: block; width: 100%; }

@media (max-width: 40rem) {
  .columns,
  .columns.three,
  .columns.narrow-first { grid-template-columns: minmax(0, 1fr); }
  .columns.narrow-first > :first-child { max-width: var(--portrait-width); }
}

/* --- Floated images ----------------------------------------------------
   ![alt](...){: .float-left } or {: .float-right }: text wraps around the
   image. Headings (h2) and rules start below it. On small screens the image
   sits on its own line instead.
   ------------------------------------------------------------------------ */

img.float-left,
img.float-right { display: block; width: var(--portrait-width); max-width: 45%; }
img.float-left  { float: left;  margin: 0.35rem var(--space-4) var(--space-2) 0; }
img.float-right { float: right; margin: 0.35rem 0 var(--space-2) var(--space-4); }
h2, hr, .columns { clear: both; }

@media (max-width: 40rem) {
  img.float-left,
  img.float-right { float: none; max-width: 100%; margin: 0 0 var(--space-4); }
}

/* Portrait on the home page */
img.portrait { border-radius: var(--radius); aspect-ratio: 4 / 5; object-fit: cover; }

/* --- Publications ------------------------------------------------------
   <div class="pub" markdown="1">  title / authors / venue / links
   ------------------------------------------------------------------------ */

.pub { margin-bottom: var(--space-4); }
.pub > p { margin: 0; }
.pub > p:nth-child(1) { font-weight: 600; color: var(--heading); line-height: 1.4; }
.pub > p:nth-child(3) { color: var(--muted); }
.pub > p:nth-child(4) { font-size: var(--text-small); margin-top: var(--space-1); }

/* --- Blog --------------------------------------------------------------- */

.post-list { list-style: none; padding: 0; }
.post-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0 var(--space-4);
  margin: 0;
  padding-block: var(--space-2);
  border-bottom: 1px solid var(--rule);
}
.post-list time {
  flex: 0 0 9rem;
  color: var(--muted);
  font-size: var(--text-small);
  font-variant-numeric: tabular-nums;
}
.post-list a { flex: 1 1 16rem; }

.post-header { margin-bottom: var(--space-4); }
.post-header h1 { margin-bottom: var(--space-2); }
.post-header .meta { margin: 0; }
.post-footer { margin-top: var(--space-5); padding-top: var(--space-3); border-top: 1px solid var(--rule); }

/* --- Footer ------------------------------------------------------------- */

.site-footer {
  border-top: 1px solid var(--rule);
  padding-block: var(--space-4);
  text-align: center;
  font-size: var(--text-small);
  color: var(--muted);
}
.site-footer p { margin: 0; }
.site-footer a { color: inherit; }

/* --- Accessibility ------------------------------------------------------ */

:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 3px;
  border-radius: 2px;
}

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

.skip-link {
  position: absolute;
  left: var(--space-3);
  top: -3rem;
  padding: var(--space-2) var(--space-3);
  background: var(--bg);
  color: var(--link);
  z-index: 10;
}
.skip-link:focus { top: var(--space-3); }

@media (max-width: 40rem) {
  :root { --text-h1: 1.7rem; --text-base: 1rem; }
  main.wrap { padding-block: var(--space-4) var(--space-5); }
}

/* Small-screen header: theme button beside the name, nav on one line. */
@media (max-width: 40rem) {
  .site-header__inner { position: relative; }
  .site-name { padding-right: 2.75rem; }
  .theme-toggle { position: absolute; top: calc(var(--space-4) - 0.35rem); right: var(--gutter); }
  .nav { font-size: 0.9rem; }
  .nav li + li::before { margin-inline: 0.4em; }
}