/* Self-as-an-End — Academic Site Stylesheet */

:root {
  --black: #0a0a0a;
  --ink: #1a1a1a;
  --mid: #555;
  --light: #888;
  --rule: #ddd;
  --bg: #fafaf8;
  --accent: #1a1a1a;
  --link: #2c2c8c;
  --link-hover: #0a0a4a;
  --serif: 'Georgia', 'Times New Roman', serif;
  --sans: 'Helvetica Neue', Arial, sans-serif;
  --mono: 'Courier New', monospace;
  --max: 780px;
  --wide: 1100px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 17px; scroll-behavior: smooth; }

body {
  font-family: var(--serif);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ── */

.site-wrap {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 2rem;
}

/* ── Header ── */

header {
  border-bottom: 2px solid var(--black);
  padding: 1.5rem 0;
  margin-bottom: 0;
}

.header-inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.site-title {
  font-family: var(--sans);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--black);
}

nav {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

nav a {
  font-family: var(--sans);
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--mid);
  text-decoration: none;
  transition: color 0.15s;
}

nav a:hover { color: var(--black); }

/* ── Hero (homepage) ── */

.hero {
  border-bottom: 1px solid var(--rule);
  padding: 4rem 0 3rem;
}

.hero-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 2rem;
}

.hero h1 {
  font-family: var(--serif);
  font-size: 2.2rem;
  font-weight: normal;
  line-height: 1.25;
  letter-spacing: -0.01em;
  margin-bottom: 0.4rem;
}

.hero .author {
  font-family: var(--sans);
  font-size: 0.88rem;
  color: var(--mid);
  letter-spacing: 0.04em;
  margin-bottom: 1.8rem;
}

.hero .intro {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ink);
  max-width: 660px;
}

.hero .intro p + p { margin-top: 1rem; }

.hero .links {
  margin-top: 2rem;
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.hero .links a {
  font-family: var(--sans);
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--link);
  text-decoration: none;
  border-bottom: 1px solid var(--link);
  padding-bottom: 1px;
  transition: all 0.15s;
}

.hero .links a:hover {
  color: var(--link-hover);
  border-color: var(--link-hover);
}

/* ── Paper Series sections ── */

.papers-section {
  padding: 3rem 0;
  border-bottom: 1px solid var(--rule);
}

.papers-section:last-child { border-bottom: none; }

.section-header {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 2rem;
  margin-bottom: 1.5rem;
}

.section-header h2 {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mid);
}

.paper-list {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 2rem;
}

.paper-item {
  display: grid;
  grid-template-columns: 2.5rem 1fr;
  gap: 0 1.25rem;
  padding: 1.1rem 0;
  border-top: 1px solid var(--rule);
  align-items: baseline;
}

.paper-item:first-child { border-top: none; }

.paper-num {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--light);
  padding-top: 0.15rem;
  text-align: right;
}

.paper-info {}

.paper-title {
  font-family: var(--serif);
  font-size: 1rem;
  font-weight: normal;
  line-height: 1.4;
}

.paper-title a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s;
}

.paper-title a:hover { border-color: var(--ink); }

.paper-subtitle {
  font-family: var(--sans);
  font-size: 0.82rem;
  color: var(--mid);
  margin-top: 0.2rem;
}

.paper-meta {
  margin-top: 0.3rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
}

.paper-meta .doi {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--light);
}

.paper-meta .doi a {
  color: inherit;
  text-decoration: none;
}

.paper-meta .doi a:hover { color: var(--link); }

.paper-meta .lang {
  font-family: var(--sans);
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--light);
  border: 1px solid var(--rule);
  padding: 0 0.35rem;
  border-radius: 2px;
}

/* ── Paper page ── */

.paper-page, .paper-container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 3rem 2rem 5rem;
}

.paper-page-header {
  border-bottom: 2px solid var(--black);
  padding-bottom: 2rem;
  margin-bottom: 2.5rem;
}

.paper-page-header .series-label {
  font-family: var(--sans);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--light);
  margin-bottom: 0.75rem;
}

.paper-page-header h1 {
  font-family: var(--serif);
  font-size: 1.85rem;
  font-weight: normal;
  line-height: 1.25;
  margin-bottom: 0.5rem;
}

.paper-page-header .paper-author {
  font-family: var(--sans);
  font-size: 0.88rem;
  color: var(--mid);
  margin-bottom: 1.25rem;
}

.paper-page-header .paper-doi {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--light);
}

.paper-page-header .paper-doi a {
  color: var(--link);
  text-decoration: none;
}

.paper-page-header .paper-doi a:hover { text-decoration: underline; }

/* Language tabs */

.lang-tabs {
  display: flex;
  gap: 0;
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--rule);
}

.lang-tab {
  font-family: var(--sans);
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  padding: 0.6rem 1.25rem;
  cursor: pointer;
  color: var(--light);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: all 0.15s;
  text-transform: uppercase;
}

.lang-tab.active {
  color: var(--black);
  border-bottom-color: var(--black);
}

.lang-tab:hover:not(.active) { color: var(--mid); }

.lang-content { display: none; }
.lang-content.active { display: block; }

/* Paper body text */

.paper-body {
  font-size: 1rem;
  line-height: 1.85;
}

.paper-body h2 {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mid);
  margin: 3rem 0 1.25rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--rule);
}

.paper-body h3 {
  font-family: var(--serif);
  font-size: 1.05rem;
  font-weight: bold;
  margin: 2rem 0 0.75rem;
}

.paper-body h4 {
  font-family: var(--serif);
  font-size: 1rem;
  font-style: italic;
  font-weight: normal;
  margin: 1.5rem 0 0.5rem;
}

.paper-body p { margin-bottom: 1.1rem; }

.paper-body p:last-child { margin-bottom: 0; }

.paper-body ul, .paper-body ol {
  margin: 0.75rem 0 1.1rem 1.5rem;
}

.paper-body li { margin-bottom: 0.4rem; }

.paper-body blockquote {
  border-left: 3px solid var(--rule);
  padding-left: 1.25rem;
  margin: 1.5rem 0;
  color: var(--mid);
  font-style: italic;
}

.paper-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9rem;
}

.paper-body th {
  font-family: var(--sans);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--mid);
  text-align: left;
  padding: 0.5rem 0.75rem;
  border-bottom: 2px solid var(--black);
}

.paper-body td {
  padding: 0.6rem 0.75rem;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}

.paper-body strong { font-weight: bold; }
.paper-body em { font-style: italic; }

.paper-body hr {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 2.5rem 0;
}

/* Abstract box */

.abstract-box {
  background: #f5f5f2;
  border-left: 3px solid var(--black);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2.5rem;
}

.abstract-box .abstract-label {
  font-family: var(--sans);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 0.6rem;
}

.abstract-box p {
  font-size: 0.95rem;
  line-height: 1.75;
  margin: 0;
}

/* Related papers */

.related-papers {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 2px solid var(--black);
}

.related-papers h2 {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 1.25rem;
}

.related-list { list-style: none; }

.related-list li {
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--rule);
  font-size: 0.9rem;
}

.related-list a {
  color: var(--link);
  text-decoration: none;
}

.related-list a:hover { text-decoration: underline; }

/* ── About / Static pages ── */

.static-page {
  max-width: var(--max);
  margin: 0 auto;
  padding: 3rem 2rem 5rem;
}

.static-page h1 {
  font-family: var(--serif);
  font-size: 1.85rem;
  font-weight: normal;
  border-bottom: 2px solid var(--black);
  padding-bottom: 1.25rem;
  margin-bottom: 2rem;
}

.static-page h2 {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mid);
  margin: 2.5rem 0 1rem;
}

.static-page p {
  margin-bottom: 1.1rem;
  line-height: 1.85;
}

.static-page a {
  color: var(--link);
  text-decoration: none;
}

.static-page a:hover { text-decoration: underline; }

/* ── Footer ── */

footer {
  border-top: 1px solid var(--rule);
  padding: 2rem 0;
  margin-top: 4rem;
}

.footer-inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-copy {
  font-family: var(--sans);
  font-size: 0.78rem;
  color: var(--light);
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-links a {
  font-family: var(--sans);
  font-size: 0.78rem;
  color: var(--light);
  text-decoration: none;
  transition: color 0.15s;
}

.footer-links a:hover { color: var(--mid); }

/* ── Responsive ── */

@media (max-width: 640px) {
  html { font-size: 16px; }
  .hero h1 { font-size: 1.65rem; }
  .paper-page-header h1 { font-size: 1.45rem; }
  .header-inner { flex-direction: column; gap: 0.5rem; }
  .paper-item { grid-template-columns: 1fr; gap: 0; }
  .paper-num { text-align: left; }
}