/* ============================================================
   vinurad.github.io — Left-rail Ledger
   Ink on paper, with a dark variant. One stylesheet, no build step.
   ============================================================ */

:root {
  --paper:     #FBFAF7;
  --ink:       #16181D;
  --muted:     #5F636A;
  --faint:     #8E939A;
  --rule:      #E2DFD8;
  --rule-soft: #EDEBE5;
  --accent:    #7A2E2E;
  --hover:     #F3F1EB;
  --rail-bg:   #F6F4EF;

  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
          "Helvetica Neue", Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua",
           Georgia, serif;
  --mono: ui-monospace, "Cascadia Mono", "SF Mono", Menlo, Consolas,
          "Liberation Mono", monospace;

  --rail-w: 15rem;
  --col-w:  34rem;
  --marg-w: 11rem;
}

/* Dark: follows the OS, unless an explicit choice is stored. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper:     #141519;
    --ink:       #E6E4DF;
    --muted:     #969BA3;
    --faint:     #6E747C;
    --rule:      #2A2C33;
    --rule-soft: #212329;
    --accent:    #C98A8A;
    --hover:     #1B1D22;
    --rail-bg:   #101115;
  }
}
:root[data-theme="dark"] {
  --paper:     #141519;
  --ink:       #E6E4DF;
  --muted:     #969BA3;
  --faint:     #6E747C;
  --rule:      #2A2C33;
  --rule-soft: #212329;
  --accent:    #C98A8A;
  --hover:     #1B1D22;
  --rail-bg:   #101115;
}

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

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { color: inherit; text-decoration: none; }

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

.skip {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--ink); color: var(--paper);
  padding: .6rem 1rem; font-family: var(--mono); font-size: .75rem;
}
.skip:focus { left: 0; }

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

/* ---------- shell ---------- */

.shell {
  display: grid;
  grid-template-columns: var(--rail-w) minmax(0, 1fr);
  min-height: 100vh;
}

/* ---------- left rail ---------- */

.rail {
  background: var(--rail-bg);
  border-right: 1px solid var(--rule);
  padding: 3rem 1.75rem 2rem;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.rail-id { display: block; margin-bottom: 2.5rem; }
.rail-name {
  display: block;
  font-size: .95rem; font-weight: 600; line-height: 1.35;
  letter-spacing: -.01em; margin-bottom: .4rem;
}
.rail-role {
  display: block;
  font-size: .72rem; line-height: 1.5; color: var(--muted);
}

.rail-nav { display: flex; flex-direction: column; }
.rail-nav a {
  font-size: .8rem;
  padding: .38rem 0;
  color: var(--muted);
  display: flex; gap: .7rem; align-items: baseline;
}
.rail-nav a .num {
  font-family: var(--mono); font-size: .62rem;
  color: var(--faint); width: 1.15rem; flex: none;
}
.rail-nav a:hover { color: var(--ink); }
.rail-nav a.on { color: var(--accent); font-weight: 500; }
.rail-nav a.on .num { color: var(--accent); }

.rail-group {
  margin: 1.9rem 0 .55rem;
  font-family: var(--mono); font-size: .6rem;
  letter-spacing: .14em; text-transform: uppercase;
  color: var(--faint);
}

.rail-btm {
  margin-top: auto;
  padding-top: 2rem;
  display: flex; flex-direction: column; align-items: flex-start; gap: .45rem;
  font-family: var(--mono); font-size: .66rem; letter-spacing: .06em;
  color: var(--muted);
}
.rail-btm a:hover { color: var(--accent); }

.theme-toggle {
  font: inherit; letter-spacing: inherit;
  background: none; border: 0; padding: 0;
  color: var(--faint); cursor: pointer;
  margin-top: .7rem;
}
.theme-toggle:hover { color: var(--accent); }
.theme-toggle::before { content: "\25D0  "; }

/* ---------- main: content column + margin column ---------- */

.main {
  display: grid;
  grid-template-columns: minmax(0, var(--col-w)) var(--marg-w);
  gap: 2.5rem;
  align-items: start;
  padding: 3rem 3rem 6rem;
}

.col { min-width: 0; }

.marg {
  font-family: var(--mono);
  font-size: .66rem; line-height: 1.6;
  color: var(--muted);
  border-left: 1px solid var(--rule);
  padding-left: 1rem;
  position: sticky;
  top: 3rem;
}
.marg-blk { margin-bottom: 1.5rem; }
.marg-lbl {
  display: block;
  font-size: .58rem; letter-spacing: .12em; text-transform: uppercase;
  color: var(--faint); margin-bottom: .3rem;
}
.marg-note { margin: 0 0 .5rem; }
.marg-note sup { color: var(--accent); padding-right: .25rem; }
.marg-note a { border-bottom: 1px solid var(--rule); }
.marg-note a:hover { color: var(--accent); border-color: var(--accent); }
.marg-series { list-style: none; margin: .4rem 0 0; padding: 0; }
.marg-series li { margin-bottom: .3rem; }
.marg-series a:hover { color: var(--accent); }
.marg-series .here { color: var(--accent); }
.marg-nav { display: flex; flex-direction: column; gap: .4rem; }
.marg-nav a:hover { color: var(--accent); }

/* ---------- page headings ---------- */

.eyebrow {
  font-family: var(--mono); font-size: .65rem;
  letter-spacing: .18em; text-transform: uppercase;
  color: var(--faint); margin: 0 0 .5rem;
}
.eyebrow a:hover { color: var(--accent); }

.h1 {
  font-size: 1.6rem; font-weight: 600; letter-spacing: -.015em;
  margin: 0 0 2.5rem;
  padding-bottom: 1.1rem;
  border-bottom: 1px solid var(--ink);
}

.lede {
  font-size: .95rem; color: var(--muted);
  margin: -1.8rem 0 2.5rem; line-height: 1.6;
}

/* ---------- grouped lists ---------- */

.group { margin-bottom: 2.6rem; }

.group-head {
  font-family: var(--mono); font-size: .64rem;
  letter-spacing: .15em; text-transform: uppercase;
  color: var(--muted); font-weight: 400;
  display: flex; align-items: center; gap: .9rem;
  margin: 0 0 .4rem;
}
.group-head::after {
  content: ""; flex: 1; height: 1px; background: var(--rule);
}
.group-head a:hover { color: var(--accent); }

.item {
  display: grid;
  grid-template-columns: 2.6rem minmax(0, 1fr) 6rem;
  gap: 1rem;
  align-items: baseline;
  padding: .62rem .6rem .62rem .1rem;
  border-bottom: 1px solid var(--rule-soft);
}
.item:hover { background: var(--hover); }
.item:hover .item-title { color: var(--accent); }

.item-no {
  font-family: var(--mono); font-size: .64rem;
  color: var(--faint); letter-spacing: .04em;
}
.item-body { min-width: 0; }
.item-title { display: block; font-size: .94rem; line-height: 1.35; }
.item-desc {
  display: block; font-size: .76rem; color: var(--muted);
  margin-top: .18rem; line-height: 1.45;
}
.item-desc em { font-style: normal; color: var(--faint); }
.item-date {
  font-family: var(--mono); font-size: .68rem;
  color: var(--faint); text-align: right;
}

/* "See all" disclosure — works with JavaScript disabled. */
.more > summary {
  list-style: none;
  cursor: pointer;
  font-family: var(--mono); font-size: .66rem;
  letter-spacing: .07em;
  color: var(--muted);
  padding: .7rem .1rem;
  border-bottom: 1px solid var(--rule-soft);
}
.more > summary::-webkit-details-marker { display: none; }
.more > summary:hover { color: var(--accent); }
.more[open] > summary { color: var(--faint); }
.more > summary .more-shut { display: none; }
.more[open] > summary .more-open { display: none; }
.more[open] > summary .more-shut { display: inline; }

.empty-note {
  font-size: .88rem; color: var(--muted);
  border-left: 2px solid var(--rule); padding-left: 1rem;
}
.empty-note code {
  font-family: var(--mono); font-size: .82em;
  background: var(--hover); padding: .1rem .3rem;
}

/* ---------- bibliography (projects) ---------- */

.bib { padding-top: .8rem; }
.bib-item {
  display: grid; grid-template-columns: 2.6rem minmax(0, 1fr);
  gap: 0 1rem;
  padding-bottom: 1.3rem; margin-bottom: 1.3rem;
  border-bottom: 1px solid var(--rule-soft);
}
.bib-no { font-family: var(--mono); font-size: .7rem; color: var(--accent); }
.bib-title { display: block; font-size: .95rem; font-weight: 600; margin-bottom: .25rem; }
.bib-meta { display: block; font-size: .8rem; color: var(--muted); }
.bib-desc { margin: .45rem 0 0; font-size: .85rem; color: var(--muted); line-height: 1.55; }
.bib-links {
  display: block; margin-top: .5rem;
  font-family: var(--mono); font-size: .68rem; letter-spacing: .05em;
  color: var(--faint);
}
.bib-links a { border-bottom: 1px solid var(--rule); }
.bib-links a:hover { color: var(--accent); border-color: var(--accent); }
.bib-links i { font-style: normal; padding: 0 .4rem; opacity: .45; }

/* ---------- post body ---------- */

.ptitle {
  font-size: 1.75rem; font-weight: 600;
  letter-spacing: -.018em; line-height: 1.2;
  margin: 0 0 2rem;
  padding-bottom: 1.1rem;
  border-bottom: 1px solid var(--ink);
}

.body {
  font-family: var(--serif);
  font-size: 1.02rem;
  line-height: 1.72;
}
.body > *:first-child { margin-top: 0; }

.body h1, .body h2 {
  font-family: var(--sans);
  font-size: .68rem; font-weight: 600;
  letter-spacing: .15em; text-transform: uppercase;
  color: var(--muted);
  margin: 2.6rem 0 .9rem;
}
.body h3, .body h4 {
  font-family: var(--sans);
  font-size: 1rem; font-weight: 600;
  letter-spacing: -.005em;
  margin: 1.9rem 0 .55rem;
}
.body p { margin: 0 0 1.1rem; }
.body ul, .body ol { padding-left: 1.3rem; margin: 0 0 1.1rem; }
.body li { margin-bottom: .5rem; }
.body li > ul, .body li > ol { margin-top: .5rem; }

.body a {
  color: var(--accent);
  border-bottom: 1px solid var(--rule);
}
.body a:hover { border-color: var(--accent); }

.body strong { font-weight: 600; }

.body blockquote {
  margin: 1.5rem 0;
  padding-left: 1.2rem;
  border-left: 2px solid var(--rule);
  color: var(--muted);
}

.body hr {
  border: 0; border-top: 1px solid var(--rule); margin: 2.5rem 0;
}

.body img { display: block; margin: 1.8rem auto; }

.body table {
  width: 100%; border-collapse: collapse;
  font-family: var(--sans); font-size: .86rem;
  margin: 1.5rem 0;
}
.body th, .body td {
  text-align: left; padding: .5rem .6rem;
  border-bottom: 1px solid var(--rule-soft);
}
.body th {
  font-family: var(--mono); font-size: .64rem;
  letter-spacing: .1em; text-transform: uppercase;
  color: var(--muted); font-weight: 400;
  border-bottom-color: var(--rule);
}

/* code */
.body code {
  font-family: var(--mono); font-size: .84em;
  background: var(--hover);
  padding: .12rem .32rem;
  border-radius: 2px;
}
.body pre {
  background: var(--hover);
  border: 1px solid var(--rule);
  padding: .9rem 1rem;
  overflow-x: auto;
  font-size: .8rem; line-height: 1.6;
  margin: 1.5rem 0;
}
.body pre code {
  background: none; padding: 0; font-size: inherit;
}
.highlight, .highlighter-rouge { background: none; }

/* figures */
.body figure { margin: 1.9rem 0; text-align: center; }
.body figure img { margin: 0 auto; }
.body figcaption {
  font-family: var(--mono); font-size: .65rem;
  color: var(--muted); margin-top: .7rem;
}

/* MathJax: long display equations scroll instead of widening the page. */
mjx-container[display="true"] {
  overflow-x: auto;
  overflow-y: hidden;
  padding: .3rem 0;
  max-width: 100%;
}
mjx-container { color: var(--ink); }

/* ---------- responsive ---------- */

@media (max-width: 1100px) {
  .main { padding: 2.5rem 2rem 5rem; gap: 2rem; }
}

/* Below this the two side columns fold into the flow. */
@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }

  .rail {
    position: static; height: auto;
    border-right: 0; border-bottom: 1px solid var(--rule);
    padding: 2rem 1.5rem;
  }
  .rail-id { margin-bottom: 1.5rem; }
  .rail-nav { flex-direction: row; flex-wrap: wrap; gap: 0 1.2rem; }
  .rail-nav a .num { display: none; }
  .rail-group { margin: 1.2rem 0 .3rem; }
  .rail-btm {
    margin-top: 1.5rem; padding-top: 1.2rem;
    border-top: 1px solid var(--rule);
    flex-direction: row; flex-wrap: wrap; gap: 1rem; align-items: center;
  }
  .theme-toggle { margin-top: 0; }

  .main {
    grid-template-columns: minmax(0, 1fr);
    padding: 2rem 1.5rem 4rem;
  }
  .marg {
    position: static;
    border-left: 0;
    border-top: 1px solid var(--rule);
    padding-left: 0; padding-top: 1.2rem;
    margin-top: 2.5rem;
    display: flex; flex-wrap: wrap; gap: 0 2.5rem;
  }
  .marg-blk { margin-bottom: 1rem; }
}

@media (max-width: 560px) {
  .item {
    grid-template-columns: 2.2rem minmax(0, 1fr);
    row-gap: .2rem;
  }
  .item-date { grid-column: 2; text-align: left; }
  .bib-item { grid-template-columns: 2.2rem minmax(0, 1fr); }
  .h1 { font-size: 1.4rem; }
  .ptitle { font-size: 1.45rem; }
}

/* ---------- print ---------- */

@media print {
  .rail, .marg, .skip, .more > summary { display: none; }
  .shell, .main { display: block; padding: 0; }
  body { background: #fff; color: #000; }
  .body a { color: #000; border: 0; }
}

/* ---------- mermaid ---------- */

.mermaid-figure {
  margin: 1.9rem 0;
  text-align: center;
  overflow-x: auto;
}
.mermaid-figure svg { max-width: 100%; height: auto; }