/* ==============================================================
   Study 1889 — academic working paper (LaTeX-like)
   Ivory paper (#f4f1e8) · ink (#2b2b2b) · sage (#425c42)
   EB Garamond · JetBrains Mono
   ============================================================== */

:root {
  --paper:   #f4f1e8;
  --paper-2: #eae5d3;
  --ink:     #2b2b2b;
  --ink-2:   #4a4a44;
  --muted:   #857f6f;
  --sage:    #425c42;
  --sage-2:  #6b8e6b;
  --accent:  #a06b3f;
  --rule:    rgba(43, 43, 43, 0.14);

  --serif: "EB Garamond", "Times New Roman", Georgia, serif;
  --mono:  "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --paper-width: 720px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-feature-settings: "kern" 1, "liga" 1, "onum" 1;
}
svg { display: block; max-width: 100%; height: auto; }
a { color: var(--sage); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: var(--accent); }
.mono { font-family: var(--mono); font-size: 0.85em; }

.skip-link {
  position: absolute; top: -40px; left: 8px;
  background: var(--sage); color: var(--paper);
  padding: 8px 12px; z-index: 100;
  font-family: var(--mono);
  font-size: 12px;
}
.skip-link:focus { top: 8px; }

/* ── Header (like LaTeX title bar) ── */
.paper-header {
  border-bottom: 1px solid var(--ink);
  padding: 20px 0;
}
.paper-header-inner {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 40px;
  flex-wrap: wrap;
}
.paper-meta { font-family: var(--mono); font-size: 11px; color: var(--muted); }
.pm-line { margin: 0; letter-spacing: 0.02em; }
.pm-issn { color: var(--sage); margin-top: 2px; }
.paper-toc ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 22px;
  flex-wrap: wrap;
}
.paper-toc a {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-2);
  text-decoration: none;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}
.paper-toc a:hover { color: var(--accent); text-decoration: none; }

/* ── Paper body ── */
.paper {
  padding: 80px 40px 100px;
}
.paper-body {
  max-width: var(--paper-width);
  margin: 0 auto;
}

/* ── Title block ── */
.ttl {
  border-bottom: 1px solid var(--ink);
  padding-bottom: 40px;
  margin-bottom: 60px;
}
.ttl-kind {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--sage);
  margin: 0 0 24px;
}
.ttl-heading {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(30px, 3.4vw, 44px);
  line-height: 1.15;
  letter-spacing: -0.005em;
  color: var(--ink);
  margin: 0 0 36px;
  text-wrap: pretty;
}
.ttl-heading span {
  display: block;
  font-weight: 400;
  font-style: italic;
  font-size: 0.72em;
  color: var(--ink-2);
  margin-top: 12px;
  line-height: 1.25;
}
.ttl-author { margin: 0 0 28px; }
.ttl-author p { margin: 0; }
.a-name {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 20px;
  color: var(--ink);
  font-style: italic;
}
.a-affil {
  font-family: var(--serif);
  font-size: 15px;
  color: var(--ink-2);
  margin-top: 4px !important;
  font-style: italic;
}
.a-affil em { font-family: var(--mono); font-style: normal; font-size: 13px; color: var(--sage); }
.a-date {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  margin-top: 8px !important;
  letter-spacing: 0.02em;
}
.ttl-doi {
  font-size: 14px;
  color: var(--ink-2);
  line-height: 1.55;
  margin: 0;
  padding-top: 20px;
  border-top: 1px dotted var(--rule);
  font-style: italic;
}
.doi-label {
  font-family: var(--mono);
  font-style: normal;
  font-size: 11px;
  color: var(--sage);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-right: 6px;
}
.ttl-doi em { color: var(--sage); }

/* ── Abstract ── */
.abstract {
  background: var(--paper-2);
  padding: 32px 36px 30px;
  border-left: 3px solid var(--sage);
  margin: 0 0 60px;
}
.abstract h2 {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--sage);
  margin: 0 0 16px;
  font-weight: 500;
}
.abstract p {
  font-size: 17px;
  line-height: 1.68;
  color: var(--ink);
  margin: 0 0 16px;
  hyphens: auto;
  -webkit-hyphens: auto;
}
.abstract p:last-child { margin-bottom: 0; }
.abstract em { color: var(--sage); font-style: italic; }
.keywords { font-size: 14px !important; color: var(--ink-2) !important; }
.keywords strong {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 12px;
  color: var(--sage);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ── Sections ── */
.sec {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 20px;
  margin: 0 0 60px;
  align-items: start;
}
.sec-num {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--sage);
  font-weight: 500;
  padding-top: 4px;
  position: sticky;
  top: 80px;
  align-self: start;
}
.sec-body h2 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 30px;
  line-height: 1.2;
  color: var(--ink);
  margin: 0 0 28px;
  letter-spacing: -0.005em;
  text-wrap: balance;
}
.sec-body h3 {
  font-family: var(--serif);
  font-weight: 500;
  font-style: italic;
  font-size: 20px;
  color: var(--sage);
  margin: 32px 0 16px;
  letter-spacing: 0.005em;
}
.sec-body p {
  font-size: 17px;
  line-height: 1.72;
  color: var(--ink);
  margin: 0 0 20px;
  hyphens: auto;
  -webkit-hyphens: auto;
}
.sec-body em { color: var(--sage); font-style: italic; }

.ordered {
  font-size: 17px;
  line-height: 1.7;
  color: var(--ink);
  padding-left: 22px;
  margin: 0 0 24px;
}
.ordered li {
  margin-bottom: 10px;
  padding-left: 6px;
}
.ordered em { color: var(--sage); font-style: italic; }

/* ── Figures ── */
.fig {
  max-width: var(--paper-width);
  margin: 30px auto 60px;
  padding: 24px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
}
.fig svg { max-width: 100%; height: auto; }
.fig figcaption {
  font-family: var(--serif);
  font-style: italic;
  font-size: 14px;
  color: var(--ink-2);
  line-height: 1.55;
  margin-top: 16px;
  text-align: center;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}
.fig figcaption strong {
  font-family: var(--mono);
  font-style: normal;
  font-size: 12px;
  color: var(--sage);
  font-weight: 500;
}

/* ── Bibliography ── */
.bib {
  border-top: 1px solid var(--ink);
  padding-top: 32px;
  margin-top: 40px;
}
.bib h2 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 22px;
  color: var(--ink);
  margin: 0 0 16px;
  font-style: italic;
}
.bib-note {
  font-size: 15px;
  color: var(--ink-2);
  font-style: italic;
  margin: 0 0 24px;
  line-height: 1.55;
}
.refs {
  list-style: decimal;
  padding-left: 24px;
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink);
  margin: 0;
}
.refs li {
  margin-bottom: 12px;
  padding-left: 4px;
}
.refs em { font-style: italic; color: var(--sage); }

/* ── Paper colophon ── */
.paper-colophon {
  margin-top: 60px;
  padding: 28px 32px;
  border: 1px solid var(--rule);
  background: var(--paper-2);
}
.paper-colophon h2 {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--sage);
  margin: 0 0 14px;
  font-weight: 500;
}
.paper-colophon p {
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink-2);
  margin: 0 0 14px;
}
.paper-colophon em { color: var(--sage); font-style: italic; }
.revision {
  font-family: var(--mono);
  font-size: 12px !important;
  color: var(--muted) !important;
  margin-top: 20px !important;
}
.revision .mono {
  color: var(--sage);
  background: var(--paper);
  padding: 1px 6px;
  border-radius: 2px;
  border: 1px solid var(--rule);
}

/* ── Foot ── */
.foot {
  background: var(--paper-2);
  border-top: 1px solid var(--ink);
  padding: 44px 40px 30px;
}
.foot-inner {
  max-width: 1140px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 40px;
  flex-wrap: wrap;
  padding-bottom: 26px;
  border-bottom: 1px solid var(--rule);
}
.foot-brand {
  font-family: var(--serif);
  font-size: 18px;
  font-style: italic;
  font-weight: 500;
  color: var(--ink);
  margin: 0 0 4px;
}
.foot-tag {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--sage);
  margin: 0;
  letter-spacing: 0.04em;
}
.foot-nav { display: flex; gap: 22px; flex-wrap: wrap; }
.foot-nav a {
  font-family: var(--mono);
  color: var(--ink-2);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.10em;
  text-decoration: none;
}
.foot-nav a:hover { color: var(--accent); text-decoration: underline; }
.foot-meta {
  max-width: 1140px;
  margin: 24px auto 0;
  font-family: var(--serif);
  font-style: italic;
  font-size: 13px;
  color: var(--muted);
  line-height: 1.6;
}

/* ── Cookie banner ── */
#cc-banner {
  position: fixed;
  left: 20px; right: 20px; top: 20px;
  z-index: 200;
  background: var(--paper);
  border: 1px solid var(--ink);
  padding: 20px 24px;
  max-width: 560px;
  margin: 0 auto;
  box-shadow: 0 4px 16px rgba(43, 43, 43, 0.08);
}
.cc-inner { display: flex; gap: 20px; align-items: center; flex-wrap: wrap; }
.cc-copy { flex: 1 1 280px; }
.cc-title {
  font-family: var(--serif);
  font-style: italic;
  font-size: 18px;
  margin: 0 0 6px;
  color: var(--ink);
  font-weight: 500;
}
.cc-text {
  font-family: var(--serif);
  font-size: 14px;
  line-height: 1.5;
  color: var(--ink-2);
  margin: 0;
}
.cc-text a { color: var(--sage); text-decoration: underline; }
.cc-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.cc-btn {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 8px 14px;
  border: 1px solid var(--ink);
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  transition: all 0.15s;
}
.cc-btn:hover { background: var(--ink); color: var(--paper); }
.cc-btn-primary { background: var(--sage); color: var(--paper); border-color: var(--sage); }
.cc-btn-primary:hover { background: var(--sage-2); border-color: var(--sage-2); }

/* ── Responsive ── */
@media (max-width: 780px) {
  .paper-header-inner { padding: 0 20px; flex-direction: column; gap: 12px; }
  .paper-toc ul { gap: 12px; }
  .paper-toc a { font-size: 10px; }
  .paper { padding: 44px 20px 60px; }
  .sec { grid-template-columns: 1fr; gap: 8px; }
  .sec-num { position: static; padding-top: 0; }
  .abstract { padding: 24px 20px; }
  .fig { padding: 16px; }
  .paper-colophon { padding: 22px 20px; }
  .foot { padding: 30px 20px 24px; }
  .foot-inner { flex-direction: column; }
  #cc-banner { left: 12px; right: 12px; top: 12px; padding: 16px; }
  .cc-inner { flex-direction: column; align-items: stretch; }
  .cc-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
  .cc-actions .cc-btn { padding: 10px; }
}

/* Dark theme optional (paper stays paper) */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #1a1a15;
    --paper-2: #22221c;
    --ink: #ede8d7;
    --ink-2: #cdc7b3;
    --muted: #857f6f;
    --sage: #8fb18f;
    --sage-2: #6b8e6b;
    --accent: #d4a56f;
    --rule: rgba(237, 232, 215, 0.14);
  }
}
:root[data-theme="dark"] {
  --paper: #1a1a15;
  --paper-2: #22221c;
  --ink: #ede8d7;
  --ink-2: #cdc7b3;
  --muted: #857f6f;
  --sage: #8fb18f;
  --sage-2: #6b8e6b;
  --accent: #d4a56f;
  --rule: rgba(237, 232, 215, 0.14);
}