/* ============================================================
   trading-models — academic working-paper stylesheet
   A refined university-press / preprint aesthetic.
   Shared by every model paper in docs/models/.
   ============================================================ */

@import url("https://fonts.googleapis.com/css2?family=Spectral:ital,wght@0,300;0,400;0,500;0,600;0,700;1,400;1,500&family=IBM+Plex+Mono:wght@400;500;600&display=swap");

:root {
  --paper:      #fcfbf7;
  --paper-edge: #f3f0e8;
  --ink:        #1c1b18;
  --ink-soft:   #44423c;
  --ink-faint:  #8a857a;
  --rule:       #d9d4c7;
  --rule-soft:  #e7e3d8;
  --accent:     #8a2b2b;   /* oxblood — links, rules, drop-caps */
  --accent-dim: #b06a52;
  --pos:        #2f6b46;
  --neg:        #a23a2e;
  --box-bg:     #f6f3ea;
  --serif: "Spectral", Georgia, "Times New Roman", serif;
  --mono:  "IBM Plex Mono", ui-monospace, "SFMono-Regular", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  background-image:
    radial-gradient(ellipse 120% 80% at 50% -20%, rgba(138,43,43,0.025), transparent 55%);
  color: var(--ink);
  font-family: var(--serif);
  font-weight: 400;
  font-size: 18.5px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-feature-settings: "onum" 1, "pnum" 1, "kern" 1, "liga" 1;
}

/* counters for sections, equations live in MathJax */
body { counter-reset: sec fig tbl; }

.paper {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 36px 140px;
}

/* ===================== MASTHEAD / TITLE BLOCK ===================== */

.preprint-bar {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding: 40px 0 14px;
  border-bottom: 2px solid var(--ink);
  gap: 16px;
  flex-wrap: wrap;
}
.preprint-bar .tag { color: var(--accent); }

.title-block { padding: 40px 0 8px; }

h1.paper-title {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(31px, 5vw, 46px);
  line-height: 1.1;
  letter-spacing: -0.012em;
  margin: 0 0 6px;
  color: var(--ink);
}
.subtitle {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 400;
  font-size: clamp(18px, 2.6vw, 22px);
  color: var(--ink-soft);
  margin: 10px 0 0;
  line-height: 1.35;
}
.byline {
  font-family: var(--serif);
  font-size: 16px;
  color: var(--ink-soft);
  margin: 22px 0 2px;
}
.byline .who { font-weight: 500; color: var(--ink); }
.dateline {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--ink-faint);
  margin: 4px 0 0;
}

/* tags row under title */
.meta-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 22px 0 0;
}
.meta-tag {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
  border: 1px solid var(--rule);
  background: var(--paper-edge);
  padding: 4px 10px;
  border-radius: 2px;
}
.meta-tag b { color: var(--ink-faint); font-weight: 600; text-transform: uppercase; font-size: 9px; letter-spacing: 0.13em; margin-right: 7px; }

/* ===================== ABSTRACT ===================== */

.abstract {
  margin: 34px 0 8px;
  padding: 26px 30px;
  background: var(--box-bg);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent);
  border-radius: 2px;
}
.abstract h2 {
  all: unset;
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 12px;
  counter-increment: none;
}
.abstract h2::before { content: none !important; }
.abstract p {
  font-size: 16.5px;
  line-height: 1.6;
  color: var(--ink-soft);
  margin: 0 0 12px;
}
.abstract p:last-child { margin-bottom: 0; }

/* keywords / JEL-style line */
.keywords {
  font-size: 15px;
  color: var(--ink-soft);
  margin: 18px 0 0;
}
.keywords b { font-variant: small-caps; letter-spacing: 0.04em; color: var(--ink); }

/* ===================== HEADINGS (numbered) ===================== */

h2 {
  counter-increment: sec;
  counter-reset: subsec;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 24px;
  letter-spacing: -0.01em;
  margin: 52px 0 4px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--rule);
  color: var(--ink);
}
h2::before {
  content: counter(sec) ".\00a0\00a0";
  color: var(--accent);
  font-weight: 600;
}
/* unnumbered headings (References, Acknowledgements) */
h2.nonum { counter-increment: none; }
h2.nonum::before { content: none; }

h3 {
  counter-increment: subsec;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 19px;
  margin: 32px 0 2px;
  color: var(--ink);
}
h3::before {
  content: counter(sec) "." counter(subsec) "\00a0\00a0";
  color: var(--accent-dim);
  font-weight: 600;
}

h4 {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 26px 0 8px;
}

/* ===================== BODY TEXT ===================== */

p { margin: 14px 0; }

/* drop cap on first paragraph after abstract's following section */
.lead::first-letter {
  font-weight: 600;
  font-size: 3.1em;
  line-height: 0.82;
  float: left;
  padding: 6px 10px 0 0;
  color: var(--accent);
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(138,43,43,0.28);
  transition: border-color .15s, background .15s;
}
a:hover { border-color: var(--accent); background: rgba(138,43,43,0.05); }

strong, b { font-weight: 600; color: var(--ink); }
em, i { font-style: italic; }

ul, ol { margin: 14px 0; padding-left: 26px; }
li { margin: 7px 0; }
li::marker { color: var(--accent-dim); }

code, .mono {
  font-family: var(--mono);
  font-size: 0.83em;
  background: var(--paper-edge);
  border: 1px solid var(--rule-soft);
  padding: 0.5px 5px;
  border-radius: 3px;
  color: var(--ink);
}

blockquote {
  margin: 20px 0;
  padding: 4px 0 4px 22px;
  border-left: 3px solid var(--rule);
  color: var(--ink-soft);
  font-style: italic;
}

/* ===================== EQUATIONS & DEFINITION BOXES ===================== */

/* MathJax display equations get breathing room */
mjx-container[display="true"] { margin: 20px 0 !important; }

/* boxed key result / definition */
.keybox {
  margin: 22px 0;
  padding: 18px 24px;
  background: var(--box-bg);
  border: 1px solid var(--rule);
  border-radius: 3px;
}
.keybox.accent { border-left: 3px solid var(--accent); }
.keybox .lab {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 6px;
}
.keybox p:first-of-type { margin-top: 0; }
.keybox p:last-child { margin-bottom: 0; }

/* a "Remark"/"Result" callout */
.remark {
  margin: 22px 0;
  padding: 16px 22px;
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent-dim);
  background: rgba(176,106,82,0.05);
  border-radius: 0 3px 3px 0;
  font-size: 17px;
}
.remark .lab {
  font-variant: small-caps;
  letter-spacing: 0.06em;
  font-weight: 600;
  color: var(--accent);
  margin-right: 8px;
}
.remark p:last-child { margin-bottom: 0; }

/* ===================== FIGURES ===================== */

figure {
  margin: 30px 0;
  padding: 0;
  text-align: center;
}
figure img {
  max-width: 100%;
  height: auto;
  border: 1px solid var(--rule);
  background: #fff;
  border-radius: 2px;
}
figcaption {
  counter-increment: fig;
  font-family: var(--serif);
  font-size: 15px;
  line-height: 1.5;
  color: var(--ink-soft);
  margin-top: 12px;
  text-align: left;
  padding: 0 8px;
}
figcaption::before {
  content: "Figure " counter(fig) ". ";
  font-weight: 600;
  color: var(--ink);
}

/* ===================== TABLES ===================== */

.table-wrap { margin: 28px 0; }
.table-wrap .tcap {
  counter-increment: tbl;
  font-family: var(--serif);
  font-size: 15px;
  color: var(--ink-soft);
  margin-bottom: 10px;
  text-align: left;
}
.table-wrap .tcap::before {
  content: "Table " counter(tbl) ". ";
  font-weight: 600;
  color: var(--ink);
}
table.data {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: 13px;
  border-top: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
}
table.data thead th {
  text-align: left;
  font-weight: 600;
  font-size: 10.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  padding: 10px 14px 9px 0;
  border-bottom: 1px solid var(--ink);
  white-space: nowrap;
}
table.data th.r, table.data td.r { text-align: right; padding-right: 0; }
table.data tbody td {
  padding: 9px 14px 9px 0;
  border-bottom: 1px solid var(--rule-soft);
  color: var(--ink-soft);
  vertical-align: baseline;
}
table.data tbody tr:last-child td { border-bottom: none; }
table.data tbody td:first-child { color: var(--ink); }
.pos { color: var(--pos); }
.neg { color: var(--neg); }

/* ===================== FOOTNOTES & REFERENCES ===================== */

.footnotes {
  margin-top: 56px;
  padding-top: 16px;
  border-top: 1px solid var(--rule);
  font-size: 14.5px;
  color: var(--ink-soft);
  line-height: 1.55;
}
.footnotes ol { padding-left: 22px; }
.footnotes li { margin: 6px 0; }

ol.references {
  font-size: 15px;
  line-height: 1.5;
  color: var(--ink-soft);
  padding-left: 26px;
}
ol.references li { margin: 11px 0; }
ol.references i { color: var(--ink); }

sup.fn a { border: none; font-size: 0.72em; }

/* ===================== NAV / FOOTER ===================== */

.paper-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 60px;
  padding-top: 22px;
  border-top: 2px solid var(--ink);
  font-family: var(--mono);
  font-size: 12px;
  flex-wrap: wrap;
}
.paper-nav a { border: none; }
.paper-nav .home { color: var(--ink-faint); }

footer.colophon {
  margin-top: 28px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--ink-faint);
  line-height: 1.8;
}

/* ===================== INDEX PAGE ===================== */

.toc { margin: 18px 0 0; }
.toc-item {
  display: block;
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 22px 26px;
  margin: 16px 0;
  background: var(--paper);
  border-left: 3px solid var(--accent);
  transition: background .15s, transform .15s;
}
.toc-item:hover { background: var(--box-bg); transform: translateX(2px); }
.toc-item .no {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}
.toc-item h3 {
  all: unset;
  display: block;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 23px;
  color: var(--ink);
  margin: 6px 0 6px;
}
.toc-item h3::before { content: none; }  /* cards are not document sections; suppress leaked 0.0 counter */
.toc-item p { margin: 0; font-size: 16px; color: var(--ink-soft); }
.toc-item .stat {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--ink-faint);
  margin-top: 12px;
}
.toc-item .stat .pos { color: var(--pos); }
.toc-item .stat .neg { color: var(--neg); }

@media (max-width: 640px) {
  body { font-size: 17px; }
  .paper { padding: 0 22px 90px; }
}