/* ==========================================================================
   Argmax — site styles
   Plain CSS, no build step. Layout inspired by a split-screen editorial
   home page: fixed hairline nav, visual column left, statements right.
   ========================================================================== */

/* ---------- Tokens ----------
   Type and palette match the personal blog (gstechschulte.github.io):
   EB Garamond throughout, "rag paper + printer ink" palette.
   Light mode only: the page ignores the OS dark-mode setting. */
:root {
  --ink: #231f1a;          /* printer ink */
  --ink-soft: #857a66;     /* blog --muted */
  --rule: #d9ccb8;         /* blog --border */
  --bg: #f4ebdd;           /* rag paper */
  --bg-transparent: rgba(244, 235, 221, 0);
  --tint: #e5d7bf;         /* blog --hover-bg-2 */
  --accent: #35566b;       /* blog code builtins (slate blue) */
  --accent-warm: #9c4f28;  /* blog --badge-text (rust) */

  --spacer: 1rem;
  --header-h: 6.5rem;

  --font-body: "EB Garamond", ui-serif, Georgia, "Times New Roman", serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --code-bg: #ece0cb;      /* blog --hover-bg: inline code pill */

  color-scheme: light only;
}

/* Spaced small capitals, like the blog's meta line / running heads. */

.main-nav,
.menu-button,
.highlight,
.site-footer {
  font-variant: small-caps;
  font-feature-settings: "smcp" 1, "lnum" 1, "kern" 1;
  letter-spacing: 0.07em;
}

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

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

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  margin: 0;
  background-color: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  font-feature-settings: "onum" 1, "pnum" 1, "kern" 1;
  line-height: 1.5;
}

h1, h2, h3, h4 {
  margin: 0;
  font-weight: 400;
}

a {
  color: inherit;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  padding: var(--spacer) var(--spacer) 2.5rem;
  /* Fade the page out under the nav instead of a hard bar. */
  background-image: linear-gradient(var(--bg) 55%, var(--bg-transparent) 100%);
  /* The fade area must not swallow clicks on content below it. */
  pointer-events: none;
  font-family: var(--font-body);
  font-size: 1.05rem;
}

.header-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: var(--spacer);
  pointer-events: auto;
}

.nav-home,
.main-nav__list > li,
.menu-button {
  border-top: 1px solid var(--ink);
  padding-top: 0.625rem;
}

.nav-home {
  grid-column: span 4;
  text-decoration: none;
}

.logotype {
  font-family: var(--font-body);
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  line-height: 1;
}

.main-nav {
  grid-column: span 8;
}

.main-nav__list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(0, 1fr));
  column-gap: var(--spacer);
}

/* Zero height + visible overflow: sub-menus drop down without
   pushing the header taller. */
.main-nav__list > li {
  height: 0;
  overflow: visible;
}

.nav-item,
.sub-nav a {
  text-decoration: none;
}

.nav-item:hover,
.nav-item:focus-visible,
.sub-nav a:hover,
.sub-nav a:focus-visible {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 5px;
}

.sub-nav {
  padding-top: 0.25rem;
  opacity: 0;
  transform: translateY(-4px);
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.sub-nav li {
  padding: 0.125rem 0 0.125rem var(--spacer);
}

.main-nav__list > li:hover .sub-nav,
.main-nav__list > li:focus-within .sub-nav {
  opacity: 1;
  transform: none;
  pointer-events: auto;
}

/* Mobile menu toggle (checkbox hack) */
.menu-toggle {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.menu-button {
  display: none;
  grid-column: span 8;
  cursor: pointer;
  user-select: none;
}

.menu-close {
  display: none;
}

.menu-arrow {
  display: inline-block;
  margin-left: 0.35rem;
  transition: transform 0.2s ease;
}

.menu-toggle:focus-visible + .header-grid .menu-button {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}

/* ---------- Home layout ---------- */
.home-main {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: var(--spacer);
  padding: 0 var(--spacer);
}

.image-column {
  grid-column: 1 / span 6;
  position: sticky;
  top: 0;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
  /* Keep the artwork clear of the nav. */
  padding-top: var(--header-h);
  padding-bottom: var(--spacer);
}

.image-track {
  height: 100%;
}

.panel {
  height: 100%;
  border-radius: 2px;
}

.text-column {
  grid-column: 7 / span 6;
}

.statement {
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1.5rem;
  padding: var(--header-h) 0 var(--spacer);
  max-width: 34rem;
  margin: 0 auto;
}

.statement h2 {
  font-size: clamp(1.75rem, 1.1rem + 1.6vw, 2.5rem);
  line-height: 1.25;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.highlight {
  align-self: flex-start;
  font-family: var(--font-body);
  font-size: 1.1rem;
  text-decoration: none;
  padding: 0.15rem 0.4rem;
  margin-left: -0.4rem;
  background: linear-gradient(var(--tint), var(--tint)) no-repeat left / 0% 100%;
  transition: background-size 0.3s ease;
}

.highlight:hover,
.highlight:focus-visible {
  background-size: 100% 100%;
}

/* ---------- Footer ---------- */
.site-footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.5rem;
  padding: 0.625rem 0 var(--spacer);
  border-top: 1px solid var(--rule);
  font-family: var(--font-body);
  font-size: 1rem;
}

.site-footer a {
  text-decoration: none;
}

.site-footer a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.separator {
  color: var(--ink-soft);
}

/* ---------- Blog ----------
   One centred column, no sidebar. The index reads like a table of
   contents (numeral · title · date · arrow) under a ruled line with
   small-cap labels sitting on it; posts are a single reading measure. */
.nav-item[aria-current="page"] {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 5px;
}

.blog-main {
  display: flex;
  flex-direction: column;
  max-width: calc(44rem + 2 * var(--spacer));
  min-height: 100vh;
  min-height: 100dvh;
  margin: 0 auto;
  padding: calc(var(--header-h) + 3rem) var(--spacer) 0;
}

.blog-main > .site-footer {
  margin-top: auto;
}

.post-index__label,
.post-index__meta,
.post-row__date,
.tag-chip,
.post-back,
.post-meta {
  color: var(--ink-soft);
  font-variant: small-caps;
  font-feature-settings: "smcp" 1, "lnum" 1, "kern" 1;
  letter-spacing: 0.07em;
}

/* Index */
.post-index {
  position: relative;
  padding-bottom: 6rem;
}

/* Labels straddle the top rule: section name left, count + feed right. */
.post-index__label,
.post-index__meta {
  position: absolute;
  top: -0.75em;
  margin: 0;
  background-color: var(--bg);
  font-size: 1.05rem;
  line-height: 1.5;
}

.post-index__label {
  left: 0;
  padding-right: 0.6rem;
  font-weight: 400;
}

.post-index__meta {
  right: 0;
  display: flex;
  gap: 0.85rem;
  padding-left: 0.6rem;
}

.post-index__meta a {
  color: var(--accent);
  text-decoration: none;
}

.post-index__meta a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.post-index__empty {
  padding-top: 2rem;
  font-style: italic;
  color: var(--ink-soft);
}

/* Placeholder info pages (About, Work, Join, Partnerships). */
.info-sections {
  border-top: 1px solid var(--rule);
}

.info-section {
  padding-top: 2rem;
  /* Keep anchored headings clear of the fixed header. */
  scroll-margin-top: calc(var(--header-h) + 1rem);
}

.info-section__title {
  margin: 0 0 0.75rem;
  font-size: 1.35rem;
  font-weight: 400;
}

.post-rows {
  counter-reset: post;
  border-top: 1px solid var(--rule);
}

.post-rows li {
  counter-increment: post;
  border-bottom: 1px solid var(--rule);
}

.post-row {
  display: flex;
  align-items: baseline;
  padding: 0.9rem 0.25rem 0.4rem 0;
  text-decoration: none;
}

/* Hanging roman numeral, generated by a CSS counter: no template logic. */
.post-row::before {
  content: counter(post, lower-roman);
  flex: 0 0 2.5rem;
  color: var(--ink-soft);
  font-variant: small-caps;
  font-feature-settings: "smcp" 1, "kern" 1;
  letter-spacing: 0.07em;
  transition: color 0.15s ease;
}

.post-row__title {
  flex: 0 1 auto;
  min-width: 0;
  font-size: 1.35rem;
  line-height: 1.3;
  transition: color 0.15s ease;
}

.post-row__date {
  flex: 0 0 auto;
  margin-left: auto;
  padding-left: 1.5rem;
  white-space: nowrap;
  transition: color 0.15s ease;
}

.post-row__arrow {
  flex: 0 0 auto;
  margin-left: 0.85rem;
  color: var(--ink-soft);
  transition: transform 0.15s ease, color 0.15s ease;
}

.post-row:hover::before,
.post-row:hover .post-row__date,
.post-row:hover .post-row__arrow,
.post-row:focus-visible .post-row__arrow {
  color: var(--accent);
}

.post-row:hover .post-row__title,
.post-row:focus-visible .post-row__title {
  color: var(--accent);
}

.post-row:hover .post-row__arrow,
.post-row:focus-visible .post-row__arrow {
  transform: translateX(0.3rem);
}

.post-row__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding: 0 0 0.9rem 2.5rem;
}

.tag-chip {
  padding: 0 0.55rem 0.05rem;
  border: 1px solid var(--rule);
  border-radius: 999px;
  font-size: 0.9rem;
  line-height: 1.5;
}

/* Single post */
.post {
  padding-bottom: 6rem;
}

.post-back {
  text-decoration: none;
  transition: color 0.15s ease;
}

.post-back:hover,
.post-back:focus-visible {
  color: var(--accent);
}

.post-head {
  margin-bottom: 2.5rem;
}

.post-title {
  margin: 1rem 0 0.75rem;
  font-size: clamp(2rem, 1.2rem + 3vw, 3rem);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.post-meta {
  margin: 0;
}

.post-lede {
  margin: 1.5rem 0 0;
  font-size: 1.35rem;
  font-style: italic;
  line-height: 1.5;
  color: var(--ink-soft);
}

.post-body {
  font-size: 1.2rem;
  line-height: 1.6;
}

.post-body p {
  margin: 1rem 0 0;
  hyphens: auto;
}

/* Drop capital on the opening paragraph only, as on the personal blog. */
.post-body > p:first-child::first-letter {
  float: left;
  padding: 0.02em 0.09em 0 0;
  margin-top: 0.02em;
  font-size: 3.4em;
  font-style: normal;
  font-weight: 500;
  line-height: 0.78;
}

.post-body h2,
.post-body h3 {
  margin: 2.5rem 0 0;
  font-weight: 500;
  font-variant: small-caps;
  font-feature-settings: "smcp" 1, "lnum" 1, "kern" 1;
  letter-spacing: 0.04em;
  line-height: 1.25;
}

.post-body h2 { font-size: 1.55rem; }
.post-body h3 { font-size: 1.3rem; }

.post-body a {
  color: var(--accent);
  text-underline-offset: 3px;
}

.post-body blockquote {
  margin: 2rem 0 0;
  padding-left: 1.25rem;
  border-left: 2px solid var(--accent-warm);
}

.post-body blockquote p {
  margin: 0;
  font-size: 1.2em;
  line-height: 1.4;
}

/* Code: matches the Subject To blog (Expressive Code, Night Owl Light).
   Token colors come from highlight-themes/night-owl-light.json, already
   contrast-adjusted the way Expressive Code does it. */
.post-body code {
  padding: 0.1em 0.35em;
  border-radius: 4px;
  background: var(--code-bg);
  font-family: var(--font-mono);
  font-size: 0.88em;
}

.post-body pre {
  clear: both;  /* never wrap beside the drop capital */
  margin: 1.5rem 0 0;
  /* 1.25rem frame padding + Expressive Code's 14.5px line inset. */
  padding: 1.1rem 1.25rem 1.1rem calc(1.25rem + 14.5px);
  overflow-x: auto;
  border: 1px solid var(--rule);
  border-radius: 8px;
  /* giallo writes the theme's own background inline; use the paper. */
  background-color: transparent !important;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* Block-level so line boxes take the code's 0.88em size: 1.6 × 12.67px
   lines, exactly Expressive Code's rhythm (not the pre's 14.4px strut). */
.post-body pre code {
  display: block;
  padding: 0;
  background: none;
}

/* Copy button (added by js/copy-code.js). Geometry, icon and behaviour
   follow Expressive Code; colours come from this palette. */
.code-frame {
  position: relative;
  clear: both;
  margin-top: 1.5rem;
}

.code-frame > pre {
  margin-top: 0;
}

/* Keep the first line clear of the button. */
.code-frame .giallo-l:first-child {
  padding-right: 2.5rem;
}

.code-copy {
  position: absolute;
  top: calc(1px + 0.4rem);
  right: calc(1px + 0.5rem);
  display: flex;
  gap: 0.25rem;
  direction: ltr;
}

.code-copy button {
  position: relative;
  width: 2.5rem;
  height: 2.5rem;
  margin: 0;
  padding: 0;
  border: none;
  border-radius: 0.2rem;
  background: var(--bg);
  opacity: 0.75;
  cursor: pointer;
  transition: opacity 0.2s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* Hover/press wash. */
.code-copy button div {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: var(--ink-soft);
  opacity: 0;
  transition: opacity 0.2s ease;
}

/* Hairline outline. */
.code-copy button::before {
  content: "";
  position: absolute;
  inset: 0;
  border: 1px solid var(--ink-soft);
  border-radius: inherit;
  opacity: 0.4;
  pointer-events: none;
}

/* Copy icon (Expressive Code's), tinted via mask. */
.code-copy button::after {
  content: "";
  position: absolute;
  inset: 0;
  margin: 0.475rem;
  background-color: var(--ink-soft);
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='1.75'%3E%3Cpath d='M3 19a2 2 0 0 1-1-2V2a2 2 0 0 1 1-1h13a2 2 0 0 1 2 1'/%3E%3Crect x='6' y='5' width='16' height='18' rx='1.5' ry='1.5'/%3E%3C/svg%3E") no-repeat;
          mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='1.75'%3E%3Cpath d='M3 19a2 2 0 0 1-1-2V2a2 2 0 0 1 1-1h13a2 2 0 0 1 2 1'/%3E%3Crect x='6' y='5' width='16' height='18' rx='1.5' ry='1.5'/%3E%3C/svg%3E") no-repeat;
  pointer-events: none;
}

.code-copy button:hover,
.code-copy button:focus-visible,
.code-copy button:active {
  opacity: 1;
}

.code-copy button:hover::after,
.code-copy button:focus-visible::after {
  background-color: var(--ink);
}

.code-copy button:hover div,
.code-copy button:focus-visible div { opacity: 0.2; }
.code-copy button:active div { opacity: 0.3; }

.code-copy button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Mouse users: hidden until the block is hovered, and a little smaller. */
@media (hover: hover) {
  .code-copy button {
    width: 2rem;
    height: 2rem;
    opacity: 0;
  }

  .code-frame:hover .code-copy button:not(:hover),
  .code-copy:focus-within button:not(:hover),
  .code-copy__feedback.is-shown ~ button:not(:hover) {
    opacity: 0.75;
  }
}

.code-copy [aria-live] {
  display: flex;
  align-items: center;
}

.code-copy__feedback {
  --arrow: 0.35rem;
  position: relative;
  margin-right: var(--arrow);
  padding: 0.125rem 0.75rem;
  border-radius: 0.2rem;
  background: #078662;  /* Expressive Code's success green on this theme */
  color: #fff;
  font-family: var(--font-body);
  font-size: 0.95rem;
  pointer-events: none;
  user-select: none;
  opacity: 0;
  transform: translateY(0.25rem);
  transition: opacity 0.2s ease-in-out, transform 0.2s ease-in-out;
}

.code-copy__feedback::after {
  content: "";
  position: absolute;
  top: calc(50% - var(--arrow));
  right: calc(-2 * (var(--arrow) - 0.5px));
  border: var(--arrow) solid transparent;
  border-left-color: #078662;
}

.code-copy__feedback.is-shown {
  opacity: 1;
  transform: none;
}

/* Math: KaTeX in ink with its own serif math faces, as on the personal blog.
   KaTeX defaults to 1.21em, sized for fonts with a large x-height. Against
   EB Garamond (x-height 0.405em vs KaTeX's 0.431em) 0.95em lines up the
   lowercase and capital heights, so math reads at the size of the text.
   Scoped to .post-body to outrank katex.min.css, which loads later and
   sets `.katex { font: … 1.21em … }` at equal specificity. */
.katex {
  color: var(--ink);
}

.post-body .katex {
  font-size: 0.95em;
}

.post-body .katex-display,
.post-body .math-display {
  clear: both;
  margin: 1.5rem 0 0;
}

/* Long equations scroll on narrow screens instead of overflowing. */
.post-body .katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 0.25rem 0;
}

.post-foot {
  margin-top: 3rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--rule);
}

/* ---------- Home artwork ---------- */

/* Scenario tree search illustration (inline SVG,
   scrubbed by scroll position via js/scroll-animation.js). */
.panel--image .traj {
  display: block;
  width: 100%;
  height: 100%;
}

/* ---------- Mobile / tablet ---------- */
@media (max-width: 991px) {
  :root {
    --header-h: 4.5rem;
  }

  .site-header {
    padding-bottom: 1rem;
    background-image: linear-gradient(var(--bg) 85%, var(--bg-transparent) 100%);
  }

  .menu-button {
    display: block;
  }

  .main-nav {
    display: none;
    grid-column: 1 / -1;
    padding-top: 1.5rem;
  }

  .main-nav__list {
    grid-template-columns: 1fr;
    row-gap: 1rem;
  }

  .main-nav__list > li {
    height: auto;
  }

  .sub-nav {
    opacity: 1;
    transform: none;
    pointer-events: auto;
  }

  .menu-toggle:checked ~ .header-grid .main-nav { display: block; }
  .menu-toggle:checked ~ .header-grid .menu-open { display: none; }
  .menu-toggle:checked ~ .header-grid .menu-close { display: inline; }
  .menu-toggle:checked ~ .header-grid .menu-arrow { transform: rotate(180deg); }

  .site-header:has(.menu-toggle:checked) {
    background: var(--bg);
    bottom: 0;
    overflow-y: auto;
  }

  .home-main {
    display: block;
  }

  .image-column {
    position: relative;
    height: 55vh;
    padding-bottom: 0;
  }

  .statement {
    min-height: 70vh;
    padding-top: 3rem;
    justify-content: flex-start;
  }

  .blog-main {
    padding-top: calc(var(--header-h) + 2.5rem);
  }

  .post-row__title {
    font-size: 1.2rem;
  }

  .post-row::before {
    flex-basis: 2rem;
  }

  .post-row__tags {
    padding-left: 2rem;
  }
}