/* =========================================================================
   Causality, Leanified — pilot stylesheet
   Two-column statement layout with hierarchical left navigation.
   ========================================================================= */

:root {
  --bg:           #fdfdfb;
  --bg-pane:     #ffffff;
  --bg-tex:      #fbf9f4;   /* warm parchment for the math */
  --bg-lean:    #f6f8fa;   /* cool grey for the code */
  --bg-sidebar: #f3f1ec;
  --fg:         #1c1c1c;
  --fg-muted:   #7a7a7a;
  --accent:     #7a1f23;   /* deep crimson */
  --accent-soft:#c2a6a8;
  --border:     #e3e0d8;
  --ok:         #2e7d4f;
  --warn:       #b58105;
  --note:       #5b6770;
  --font-text:  "Source Serif Pro", "Georgia", "Cambria", serif;
  --font-ui:    "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono:  "JetBrains Mono", "SF Mono", "Menlo", "Consolas", monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-text);
  font-size: 16px;
  line-height: 1.55;
}

/* ----------------------------------------------------------------- header */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg-pane);
  font-family: var(--font-ui);
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-title strong  { font-size: 1.05rem; color: var(--accent); letter-spacing: 0.01em; }
.site-title .subtitle { color: var(--fg-muted); margin-left: 0.5rem; font-size: 0.9rem; }
.site-meta a { color: var(--fg-muted); text-decoration: none; font-size: 0.9rem; }
.site-meta a:hover { color: var(--accent); }

/* --------------------------------------------------------------- about bar */

.about-bar {
  background: #fbf6ec;
  border-bottom: 1px solid var(--border);
  padding: 0.7rem 1.5rem;
  font-family: var(--font-ui);
  font-size: 0.88rem;
  color: var(--fg);
  line-height: 1.5;
}
.about-bar p { margin: 0; max-width: 78ch; }
.about-bar a { color: var(--accent); text-decoration: none; border-bottom: 1px solid var(--accent-soft); }
.about-bar a:hover { border-bottom-color: var(--accent); }
.about-bar em { font-style: italic; }

/* ----------------------------------------------------------------- layout */

.layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  min-height: calc(100vh - 56px);
}

/* ----------------------------------------------------------- left sidebar */

.sidebar {
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  padding: 1rem 0.75rem 2rem 1rem;
  font-family: var(--font-ui);
  font-size: 0.92rem;
  overflow-y: auto;
  max-height: calc(100vh - 56px);
  position: sticky;
  top: 56px;
}

.sidebar-search {
  width: 100%;
  padding: 0.4rem 0.55rem;
  font-family: var(--font-ui);
  font-size: 0.85rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg-pane);
  color: var(--fg-muted);
  margin-bottom: 0.85rem;
}

.sidebar details { margin: 0.1rem 0; }
.sidebar summary {
  cursor: pointer;
  padding: 0.3rem 0.2rem;
  border-radius: 4px;
  list-style: none;
  font-weight: 500;
  user-select: none;
}
.sidebar summary::-webkit-details-marker { display: none; }
.sidebar summary::before {
  content: "▸";
  display: inline-block;
  width: 1em;
  color: var(--fg-muted);
  transition: transform 0.12s;
}
.sidebar details[open] > summary::before { transform: rotate(90deg); }
.sidebar summary:hover { background: rgba(0,0,0,0.04); }

.sidebar .ch > summary    { color: var(--accent); font-weight: 600; margin-top: 0.5rem; }
.sidebar .sec > summary   { color: var(--fg); padding-left: 0.7rem; }
.sidebar ul {
  list-style: none;
  margin: 0.2rem 0 0.4rem 1.7rem;
  padding: 0;
  border-left: 1px dotted var(--border);
}
.sidebar ul li { padding: 0.15rem 0 0.15rem 0.55rem; }
.sidebar ul li a {
  text-decoration: none;
  color: var(--fg);
  display: block;
  padding: 0.15rem 0.35rem;
  border-radius: 3px;
  font-size: 0.88rem;
}
.sidebar ul li a:hover  { background: rgba(122,31,35,0.07); color: var(--accent); }
.sidebar ul li a.active {
  background: var(--accent);
  color: #fff;
  font-weight: 500;
}
.sidebar .muted { color: var(--fg-muted); font-style: italic; font-size: 0.85rem; padding-left: 0.55rem; }

/* ---------------------------------------------------------------- content */

.content {
  padding: 2rem 2.5rem 4rem 2.5rem;
  max-width: 1400px;
}

/* ---- one entry (def / claim) ---- */

.entry {
  background: var(--bg-pane);
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-bottom: 2rem;
  box-shadow: 0 1px 2px rgba(0,0,0,0.02);
}

.entry-header {
  padding: 1.1rem 1.4rem 0.8rem 1.4rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.entry-kind {
  font-family: var(--font-ui);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
}
.entry-title {
  margin: 0;
  font-size: 1.45rem;
  font-weight: 600;
  line-height: 1.25;
}
.entry-status { margin-top: 0.4rem; display: flex; gap: 0.4rem; flex-wrap: wrap; }

.badge {
  display: inline-block;
  font-family: var(--font-ui);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  padding: 0.15rem 0.55rem;
  border-radius: 99px;
  border: 1px solid currentColor;
}
.badge-ok   { color: var(--ok); }
.badge-warn { color: var(--warn); }
.badge-note { color: var(--note); }

/* ---- the split ---- */

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
}

.pane { display: flex; flex-direction: column; min-width: 0; }
.pane-tex  { background: var(--bg-tex);  border-right: 1px solid var(--border); }
.pane-lean { background: var(--bg-lean); }

.pane-label {
  font-family: var(--font-ui);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--fg-muted);
  padding: 0.55rem 1.1rem;
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.5);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
}
.pane-label-aux {
  text-transform: none;
  letter-spacing: 0;
  font-size: 0.78rem;
  color: var(--fg-muted);
}
.pane-label-aux code {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent);
}

.pane-body { padding: 1.1rem 1.4rem 1.3rem 1.4rem; flex: 1; }
.pane-tex .pane-body  { font-family: var(--font-text); font-size: 1.02rem; }
.pane-tex p:first-child { margin-top: 0; }
.pane-tex em            { font-style: italic; }

/* Roman-numeral parenthesised list — matches \begin{enumerate}[label=\roman*.)] */
ol.roman-paren {
  list-style: none;
  counter-reset: roman-counter;
  padding-left: 0;
  margin: 0.6rem 0;
}
ol.roman-paren > li {
  counter-increment: roman-counter;
  position: relative;
  padding-left: 2.4rem;
  margin: 0.2rem 0;
}
ol.roman-paren > li::before {
  content: counter(roman-counter, lower-roman) ".)";
  position: absolute;
  left: 0.4rem;
  width: 1.6rem;
  text-align: right;
  color: var(--fg-muted);
}
ol.roman-paren > li.no-marker {
  padding-left: 2.4rem;
}
ol.roman-paren > li.no-marker::before { content: ""; }

/* Lean code block */
.pane-lean .pane-body { padding: 0; }
.pane-lean pre {
  margin: 0;
  padding: 1.1rem 1.4rem;
  background: var(--bg-lean);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.86rem;
  line-height: 1.5;
}
.pane-lean code { font-family: inherit; background: transparent; }

/* ---- action row ---- */

.entry-actions {
  padding: 0.9rem 1.4rem;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  background: var(--bg-pane);
}
.btn {
  font-family: var(--font-ui);
  font-size: 0.85rem;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--accent);
  color: var(--accent);
  background: transparent;
  border-radius: 4px;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.12s, color 0.12s;
}
.btn:hover {
  background: var(--accent);
  color: #fff;
}
.btn-disabled {
  border-color: var(--border);
  color: var(--fg-muted);
  cursor: not-allowed;
  pointer-events: none;
  opacity: 0.7;
}

/* ---- design notes (collapsible) ---- */

.design-notes {
  border-top: 1px solid var(--border);
  background: rgba(0,0,0,0.015);
}
.design-notes summary {
  cursor: pointer;
  padding: 0.7rem 1.4rem;
  font-family: var(--font-ui);
  font-size: 0.88rem;
  color: var(--accent);
  list-style: none;
}
.design-notes summary::before {
  content: "▸ ";
  color: var(--fg-muted);
}
.design-notes[open] summary::before { content: "▾ "; }
.design-notes-body {
  padding: 0.4rem 1.4rem 1.2rem 1.4rem;
  font-size: 0.92rem;
}
.design-notes-body ul { padding-left: 1.2rem; }
.design-notes-body li { margin: 0.4rem 0; }
.design-notes-body code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  background: rgba(0,0,0,0.05);
  padding: 0.05rem 0.3rem;
  border-radius: 3px;
}

/* ---- placeholder ---- */

.entry.placeholder { opacity: 0.45; }
.entry.placeholder .entry-title { font-weight: 400; }

.muted { color: var(--fg-muted); font-style: italic; }

/* ---- proof panes (claims) ---- */

.tex-proof-pane,
.lean-proof-pane {
  border-top: 1px solid var(--border);
}
.tex-proof-pane  { background: var(--bg-tex);  }
.lean-proof-pane { background: var(--bg-lean); }
.tex-proof-pane .pane-body  { padding: 1.1rem 1.4rem; font-family: var(--font-text); font-size: 1.02rem; }
.lean-proof-pane .pane-body { padding: 0; }
.lean-proof-pane pre {
  margin: 0;
  padding: 1.1rem 1.4rem;
  font-family: var(--font-mono);
  font-size: 0.86rem;
  line-height: 1.5;
  overflow-x: auto;
}
.lean-part-label {
  font-family: var(--font-ui);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-muted);
  padding: 0.6rem 1.4rem 0.2rem;
}
.tex-proof .proof-label {
  font-weight: 600;
  margin-right: 0.4em;
  font-variant-caps: small-caps;
}

/* ---- design notes pre ---- */

.design-notes-body pre {
  background: var(--bg-lean);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.9rem 1.1rem;
  margin: 0;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.5;
  white-space: pre;
}

/* ---- sidebar: unavailable rows ---- */

.sidebar ul li a.unavailable {
  color: var(--fg-muted);
  font-style: italic;
}
.sidebar ul li a.unavailable:hover {
  background: rgba(0, 0, 0, 0.04);
  color: var(--fg-muted);
}

/* ---- loading / missing ---- */

.loading {
  padding: 3rem;
  color: var(--fg-muted);
  text-align: center;
  font-family: var(--font-ui);
}
.missing {
  padding: 1rem 1.4rem;
  color: var(--fg-muted);
  font-style: italic;
}
.missing-body {
  padding: 1rem 1.4rem 1.4rem;
  font-family: var(--font-ui);
}
.missing-body pre {
  background: var(--bg-lean);
  padding: 0.7rem 1rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

/* ---- responsive: collapse split on small screens ---- */

@media (max-width: 1100px) {
  .split { grid-template-columns: 1fr; }
  .pane-tex { border-right: none; border-bottom: 1px solid var(--border); }
}
@media (max-width: 800px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: static; max-height: none; }
  .content { padding: 1rem; }
}