/* ============================================================
   Rindler horizon note — shared stylesheet (EN / JA)
   Design: quiet academic paper, with a color-coded "epistemic
   status" system (theorem / physical input / assumption) that
   mirrors the note's own core distinction between what is proved
   and what is imported as input.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Newsreader:ital,opsz,wght@0,6..72,400;0,6..72,500;0,6..72,600;1,6..72,400&family=Noto+Serif+JP:wght@400;500;600&family=JetBrains+Mono:wght@400;500&display=swap');

:root{
  --bg:            #f2f3ef;
  --bg-card:       #fbfbf9;
  --ink:           #1d211f;
  --ink-soft:      #4c534f;
  --ink-faint:     #7a827c;
  --rule:          #d7d9d1;
  --rule-strong:   #b9bcb2;

  --c-theorem:     #2f6f62;
  --c-theorem-bg:  #e9f2ef;
  --c-input:       #9c6b15;
  --c-input-bg:    #f6eede;
  --c-assumption:  #55606c;
  --c-assumption-bg:#eaedf1;
  --c-notclaimed:  #8a3b3b;
  --c-notclaimed-bg:#f5eae9;

  --link:          #1b3a5c;
  --link-hover:    #2e5c8a;

  --serif:  "Newsreader", "Noto Serif JP", "Hiragino Mincho ProN", serif;
  --serif-ja: "Noto Serif JP", "Newsreader", "Hiragino Mincho ProN", serif;
  --mono:   "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --measure: 42rem;
}

*{ box-sizing: border-box; }
html{ -webkit-text-size-adjust: 100%; }

body{
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
body.lang-ja{ font-family: var(--serif-ja); }

::selection{ background: var(--c-theorem-bg); color: var(--ink); }

a{ color: var(--link); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover{ color: var(--link-hover); }

/* ---------- header / footer nav ---------- */

.site-bar{
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.5rem;
  background: rgba(242,243,239,0.92);
  backdrop-filter: saturate(140%) blur(6px);
  border-bottom: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}
footer.site-bar{
  position: static;
  margin-top: 3.5rem;
  background: transparent;
}
.site-bar nav{ display: flex; gap: 1.1rem; align-items: center; }
.site-bar a{
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
}
.site-bar a:hover{ color: var(--ink); border-bottom-color: var(--ink-soft); }
.site-bar a.current{ color: var(--ink); font-weight: 500; }
.site-bar .sep{ color: var(--rule-strong); }
.lang-switch{
  display: flex;
  gap: 0.5rem;
  align-items: center;
}
.lang-switch span, .lang-switch a{ font-family: var(--mono); font-size: 0.72rem; }

/* ---------- hero ---------- */

.hero{
  max-width: var(--measure);
  margin: 0 auto;
  padding: 3.6rem 1.5rem 2rem;
}
.hero .eyebrow{
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 1rem;
}
.hero h1{
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(1.6rem, 4.4vw, 2.35rem);
  line-height: 1.28;
  letter-spacing: -0.01em;
  margin: 0 0 1.4rem;
}
body.lang-ja .hero h1{ font-family: var(--serif-ja); }

.status-banner{
  border: 1px solid var(--rule-strong);
  border-left: 3px solid var(--ink-soft);
  background: var(--bg-card);
  padding: 1rem 1.15rem;
  font-size: 0.92rem;
  color: var(--ink-soft);
  line-height: 1.65;
}
.status-banner strong{ color: var(--ink); }

/* ---------- legend ---------- */

.legend{
  max-width: var(--measure);
  margin: 1.6rem auto 0;
  padding: 0 1.5rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.1rem;
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--ink-soft);
}
.legend .chip-dot{
  display: inline-block;
  width: 0.55rem; height: 0.55rem;
  border-radius: 50%;
  margin-right: 0.4rem;
  vertical-align: middle;
  position: relative;
  top: -1px;
}
.dot-theorem{ background: var(--c-theorem); }
.dot-input{ background: var(--c-input); }
.dot-assumption{ background: var(--c-assumption); }

/* ---------- article body ---------- */

article{
  max-width: var(--measure);
  margin: 0 auto;
  padding: 2.2rem 1.5rem 5rem;
}

section{ margin-top: 3rem; }
section:first-of-type{ margin-top: 1.5rem; }

h2{
  font-family: var(--serif);
  font-weight: 500;
  font-size: 1.5rem;
  line-height: 1.35;
  margin: 0 0 1.1rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--rule);
}
body.lang-ja h2{ font-family: var(--serif-ja); }

h2 .num{
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--ink-faint);
  margin-right: 0.55rem;
}

h3{
  font-family: var(--serif);
  font-weight: 500;
  font-style: italic;
  font-size: 1.15rem;
  margin: 2.1rem 0 0.9rem;
  color: var(--ink);
}
body.lang-ja h3{ font-family: var(--serif-ja); font-style: normal; }

p{ margin: 0 0 1.05rem; }
strong{ font-weight: 600; }

ul, ol{ margin: 0 0 1.1rem; padding-left: 1.3rem; }
li{ margin-bottom: 0.5rem; }
li::marker{ color: var(--ink-faint); }

code{
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--bg-card);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 0.05em 0.35em;
}

hr{
  border: none;
  border-top: 1px solid var(--rule);
  margin: 2.6rem 0;
}

/* section header tint bar — set per-section via data-status */
.section-tag{
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  padding: 0.22rem 0.55rem;
  border-radius: 999px;
  margin-bottom: 0.9rem;
}
.tag-theorem{ color: var(--c-theorem); background: var(--c-theorem-bg); }
.tag-input{ color: var(--c-input); background: var(--c-input-bg); }
.tag-assumption{ color: var(--c-assumption); background: var(--c-assumption-bg); }
.tag-mixed{ color: var(--ink-soft); background: var(--bg-card); border: 1px solid var(--rule); }

/* boxed / blockquote "result" cards */
blockquote{
  margin: 1.4rem 0;
  padding: 1.1rem 1.3rem;
  background: var(--bg-card);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--ink);
  font-size: 0.97rem;
}
blockquote p:last-child{ margin-bottom: 0; }

.result-box{
  margin: 1.4rem 0;
  padding: 1.15rem 1.3rem;
  background: var(--c-theorem-bg);
  border: 1px solid #cfe3dc;
  border-radius: 4px;
}
.result-box.final{
  background: var(--bg-card);
  border: 1px solid var(--rule-strong);
  border-left: 3px solid var(--ink);
}

/* caution / caveat callouts */
.callout{
  margin: 1.4rem 0;
  padding: 1rem 1.2rem;
  border-radius: 4px;
  font-size: 0.95rem;
}
.callout-input{ background: var(--c-input-bg); border: 1px solid #e6d3ab; }
.callout-assumption{ background: var(--c-assumption-bg); border: 1px solid #d3d9e0; }
.callout p:last-child{ margin-bottom: 0; }

/* assumption / input summary grid (was: table in §6.1) */
.assumption-grid{
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 0.7rem;
  margin: 1.3rem 0 1.6rem;
}
.assumption-card{
  background: var(--bg-card);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--c-assumption);
  border-radius: 3px;
  padding: 0.8rem 0.9rem;
}
.assumption-card.theorem{ border-left-color: var(--c-theorem); }
.assumption-card.input{ border-left-color: var(--c-input); }
.assumption-card .label{
  font-family: var(--mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--ink);
}
.assumption-card .content{
  font-size: 0.88rem;
  color: var(--ink-soft);
  margin: 0.3rem 0;
}
.assumption-card .source{
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--ink-faint);
}

/* §9 "explicitly not claimed" */
.not-claimed{
  list-style: none;
  padding-left: 0;
  margin: 1.3rem 0;
}
.not-claimed li{
  position: relative;
  padding: 0.7rem 0.9rem 0.7rem 2.1rem;
  margin-bottom: 0.55rem;
  background: var(--c-notclaimed-bg);
  border-radius: 3px;
  font-size: 0.94rem;
}
.not-claimed li::before{
  content: "✕";
  position: absolute;
  left: 0.75rem;
  top: 0.68rem;
  color: var(--c-notclaimed);
  font-size: 0.8rem;
  font-family: var(--mono);
}

/* references */
.ref-list{ list-style: none; padding: 0; margin: 1.3rem 0; }
.ref-list li{
  padding: 0.9rem 0 0.9rem;
  border-top: 1px solid var(--rule);
  font-size: 0.93rem;
}
.ref-list li:first-child{ border-top: none; }
.ref-list .cite{ color: var(--ink); }
.ref-list .gloss{ color: var(--ink-soft); display: block; margin-top: 0.3rem; }

/* math */
mjx-container{ overflow-x: auto; overflow-y: hidden; max-width: 100%; }

/* misc */
.divider-label{
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--ink-faint);
  text-align: center;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin: 2.6rem 0 -0.8rem;
}

footer.site-bar .foot-note{
  font-family: var(--serif);
  font-size: 0.82rem;
  color: var(--ink-faint);
}
body.lang-ja footer.site-bar .foot-note{ font-family: var(--serif-ja); }

/* ---------- mobile ---------- */
@media (max-width: 640px){
  body{ font-size: 16px; line-height: 1.72; }
  .site-bar{ padding: 0.7rem 1rem; flex-wrap: wrap; row-gap: 0.4rem; }
  .site-bar nav{ gap: 0.8rem; }
  .hero{ padding: 2.2rem 1.1rem 1.4rem; }
  .legend{ padding: 0 1.1rem; font-size: 0.7rem; }
  article{ padding: 1.6rem 1.1rem 3.5rem; }
  h2{ font-size: 1.28rem; }
  h3{ font-size: 1.05rem; }
  blockquote, .result-box, .callout{ padding: 0.9rem 1rem; }
  .assumption-grid{ grid-template-columns: 1fr; }
  section{ margin-top: 2.3rem; }
}

@media (max-width: 400px){
  .site-bar{ font-size: 0.72rem; }
  .hero h1{ font-size: 1.42rem; }
}