/* ---------- Base ---------- */
:root{
  --ink: #111;
  --muted: #444;
  --rule: rgba(0,0,0,.22);
  --paper: #fbf7ef;               /* warm paper tone */
  --paper-edge: rgba(0,0,0,.06);
  --link: #0b3a6f;
  --maxw: 860px;
  --lh: 1.62;
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }

body{
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(1200px 800px at 20% 10%, rgba(0,0,0,.04), transparent 55%),
    radial-gradient(900px 700px at 80% 30%, rgba(0,0,0,.035), transparent 60%),
    linear-gradient(180deg, #f6f2ea, var(--paper));
  font-family: "STIX Two Text", "Times New Roman", Times, serif;
  line-height: var(--lh);
  letter-spacing: .005em;
}

/* Subtle “paper” frame */
.page{
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 2.75rem 1.25rem 4rem;
  background: rgba(255,255,255,.28);
  box-shadow: 0 0 0 1px var(--paper-edge), 0 20px 70px rgba(0,0,0,.08);
  border-radius: 12px;
  backdrop-filter: blur(1px);
}

/* ---------- Header / Nav ---------- */
.site-header{
  max-width: var(--maxw);
  margin: 1.25rem auto 0;
  padding: 0 1.25rem;
}

.masthead{
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.brand{
  display: flex;
  align-items: baseline;
  gap: .5rem;
}

.brand-mark{
  font-size: 1.15rem;
  opacity: .85;
}

.brand-name{
  font-variant: small-caps;
  letter-spacing: .06em;
  font-size: .95rem;
  color: var(--muted);
}

.nav{
  display: flex;
  gap: .9rem;
  align-items: center;
  flex-wrap: wrap;
}

.nav a{
  color: var(--link);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}

.nav a:hover{
  border-bottom-color: var(--link);
}

.print-btn{
  font: inherit;
  padding: .22rem .55rem;
  border: 1px solid var(--rule);
  background: rgba(255,255,255,.55);
  border-radius: 8px;
  cursor: pointer;
}
.print-btn:hover{ background: rgba(255,255,255,.72); }

.rule{
  border: none;
  border-top: 1px solid var(--rule);
  margin: .75rem 0 0;
}

.rule.subtle{ opacity: .65; }

/* ---------- Accessibility ---------- */
.skip-link{
  position: absolute;
  left: -9999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}
.skip-link:focus{
  left: 1rem;
  top: 1rem;
  width: auto;
  height: auto;
  padding: .5rem .75rem;
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 10px;
  z-index: 999;
}

/* ---------- Front matter ---------- */
.frontmatter{
  text-align: center;
  padding-top: .25rem;
}

.epigraph{
  margin: 0 auto;
  max-width: 44rem;
  font-size: 1.02rem;
  color: var(--muted);
}

.spacer{
  height: 34vh; /* mimics LaTeX vspace*{0.35\textheight} */
  min-height: 10rem;
}

.dedication p{
  margin: .15rem 0;
  color: var(--muted);
}

.double-space{ height: 2.25rem; }

.closing-quote{
  margin: 0 auto 1.5rem;
  max-width: 36rem;
  padding: .75rem 1rem;
  border-left: 2px solid var(--rule);
  text-align: left;
  background: rgba(255,255,255,.25);
}

.quote-attrib{
  font-variant: small-caps;
  letter-spacing: .05em;
  color: var(--muted);
}

.page-break{
  border: none;
  border-top: 1px solid var(--rule);
  margin: 2.25rem 0;
}

/* ---------- Title page ---------- */
.titlepage{
  padding-top: .5rem;
}

.titlepage-heading{
  text-align: center;
  font-size: 1.35rem;
  margin: 0 0 1rem;
  letter-spacing: .02em;
}

.titlepage-box{
  max-width: 42rem;
  margin: 0 auto;
  padding: 1rem 1.15rem;
  background: rgba(255,255,255,.32);
  border: 1px solid var(--paper-edge);
  border-radius: 12px;
}

.titlepage-box p{
  margin: .75rem 0;
}

.smallcaps{
  font-variant: small-caps;
  letter-spacing: .03em;
}

.leadin{
  margin-top: 1.1rem;
  margin-bottom: .35rem;
}

.assumptions{
  margin: .35rem 0 1rem;
  padding-left: 1.25rem;
}

.signoff{
  margin-top: 1.25rem;
  text-align: right;
}

/* Footnotes */
.fn-ref a{
  text-decoration: none;
  color: var(--link);
  border-bottom: 1px dotted var(--link);
}
.footnotes{
  max-width: 42rem;
  margin: .9rem auto 0;
  color: var(--muted);
  font-size: .95rem;
}
.footnotes ol{
  margin: 0;
  padding-left: 1.25rem;
}
.footnotes li{
  margin: .5rem 0;
}
.fn-back{
  text-decoration: none;
  margin-left: .35rem;
  color: var(--link);
}

/* ---------- Paper ---------- */
.paper-header{
  text-align: center;
  margin-top: .25rem;
}

.paper-kicker{
  margin: 0;
  font-variant: small-caps;
  letter-spacing: .08em;
  color: var(--muted);
}

.paper-title{
  margin: .35rem 0 .75rem;
  font-size: 1.6rem;
  line-height: 1.25;
}

.byline{
  margin: 0 0 1.5rem;
  color: var(--muted);
}

.byline p{ margin: .1rem 0; }

.author{
  font-size: 1.05rem;
  color: var(--ink);
}

.section-title{
  font-size: 1.05rem;
  margin: 0 0 .75rem;
  letter-spacing: .02em;
}

.abstract{
  max-width: 46rem;
  margin: 0 auto;
  text-align: left;
}

.abstract p{
  margin: .85rem 0;
  text-align: justify;
  hyphens: auto;
}

.equation{
  margin: 1rem auto;
  padding: .65rem .75rem;
  border-top: 1px solid var(--paper-edge);
  border-bottom: 1px solid var(--paper-edge);
  background: rgba(255,255,255,.18);
  border-radius: 10px;
  overflow-x: auto;
}

/* Footer */
.paper-footer{
  margin-top: 2rem;
  text-align: center;
  color: var(--muted);
  font-size: .95rem;
}

.footer-note{ margin: .75rem 0 0; }

/* ---------- Print ---------- */
@media print{
  body{
    background: #fff !important;
  }
  .site-header, .print-btn, .nav{
    display: none !important;
  }
  .page{
    box-shadow: none !important;
    background: transparent !important;
    max-width: none !important;
    margin: 0 !important;
    padding: 0 !important;
    border-radius: 0 !important;
  }
  .spacer{ height: 3.5in; } /* mimic title spacing on paper */
  a{ color: #000; text-decoration: none; }
}

.sec{
  font-size: 1.35rem;
  margin: 2.2rem 0 .75rem;
}

.subsec{
  font-size: 1.1rem;
  margin: 1.6rem 0 .5rem;
}

.para{
  font-size: 1.0rem;
  font-style: italic;
  margin: 1.2rem 0 .35rem;
}

.itemize{
  margin: .75rem 0 1rem;
  padding-left: 1.25rem;
}

.parameter-box{
  margin: 1.25rem auto;
  max-width: 46rem;
  padding: .75rem;
  border: 1px solid rgba(0,0,0,.18);
  background: rgba(255,255,255,.25);
  border-radius: 12px;
}

.parameter-box-inner{
  border-top: 1px solid rgba(0,0,0,.25);
  border-bottom: 1px solid rgba(0,0,0,.25);
  padding: .6rem .85rem;
}

.parameter-box-title{
  margin: 0 0 .6rem;
  font-size: .98rem;
  font-weight: 600;
}

.figure img{
  width: 100%;
  height: auto;
  border-radius: 10px;
  box-shadow: 0 10px 30px rgba(0,0,0,.10);
}

.figure figcaption{
  margin-top: .55rem;
  color: rgba(0,0,0,.75);
  font-size: .95rem;
  text-align: justify;
}

.paper-top{
  max-width: var(--maxw);
  margin: 1.25rem auto 0;
  padding: 0 1.25rem;
}

.paper-top-inner{
  display:flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.paper-top-brand{
  display:flex;
  align-items: baseline;
  gap:.5rem;
}

.paper-top-meta{
  margin-top: .25rem;
  color: var(--muted);
  font-size: .95rem;
}

.paper-label{
  font-variant: small-caps;
  letter-spacing: .08em;
}

.paper-sep{ opacity: .6; padding: 0 .35rem; }

.paper-title-short{
  font-style: italic;
}

.paper-nav{
  display:flex;
  align-items:center;
  gap:.9rem;
  flex-wrap: wrap;
}

.paper-nav a{
  color: var(--link);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}

.paper-nav a:hover{
  border-bottom-color: var(--link);
}