/* STYX v1 specification site - shared stylesheet.
   Obsidian-water dark theme, marble type, antique gold accent. */

@import url("fonts.css");

:root {
  --bg:        #0b0e12;
  --bg-deep:   #07090c;
  --surface:   #10141a;
  --surface2:  #161b23;
  --line:      #222933;
  --line-soft: #1a2028;
  --ink:       #eae5d6;
  --body:      #b9b3a3;
  --muted:     #7e7b6e;
  --gold:      #c8a45c;
  --gold-dim:  #97814e;
  --gold-soft: rgba(200, 164, 92, 0.10);
  --river:     #7fa3bc;
  --river-soft: rgba(127, 163, 188, 0.10);
  --ok:        #93ad84;
  --warn:      #c98a6a;
  --display: "GFS Didot", "Didot", Georgia, serif;
  --serif:   "Source Serif 4", Georgia, "Times New Roman", serif;
  --mono:    "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;
  --sidebar-w: 268px;
  --measure: 47rem;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--body);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* faint depth gradient behind everything: dark water */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(1200px 700px at 85% -10%, rgba(127,163,188,0.05), transparent 60%),
    radial-gradient(900px 600px at -10% 110%, rgba(200,164,92,0.04), transparent 55%),
    var(--bg);
}

::selection { background: rgba(200,164,92,0.28); color: var(--ink); }

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

.wrap { display: flex; min-height: 100vh; }

/* sidebar */
.side {
  width: var(--sidebar-w);
  flex: none;
  position: sticky;
  top: 0;
  align-self: flex-start;
  height: 100vh;
  overflow-y: auto;
  scrollbar-width: thin;
  padding: 30px 26px 40px 30px;
  border-right: 1px solid var(--line-soft);
  background: linear-gradient(180deg, rgba(7,9,12,0.55), rgba(7,9,12,0.0) 220px);
}

.brand { display: block; text-decoration: none; margin-bottom: 6px; }
.brand .name {
  font-family: var(--display);
  font-size: 30px;
  letter-spacing: 0.26em;
  color: var(--ink);
  line-height: 1.1;
}
.brand .name .xi { color: var(--gold); }
.brand .tag {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 6px;
}

.side .meander { margin: 18px 0 20px; }

.side nav a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 6.5px 10px 6.5px 8px;
  margin-left: -8px;
  border-radius: 6px;
  text-decoration: none;
  color: var(--body);
  font-size: 14.5px;
  line-height: 1.35;
  transition: color .14s ease, background .14s ease;
}
.side nav a .num {
  font-family: var(--display);
  font-size: 12px;
  color: var(--muted);
  min-width: 22px;
  text-align: right;
  flex: none;
  transition: color .14s ease;
}
.side nav a:hover { color: var(--ink); background: rgba(234,229,214,0.03); }
.side nav a:hover .num { color: var(--gold-dim); }
.side nav a.here { color: var(--gold); background: var(--gold-soft); }
.side nav a.here .num { color: var(--gold); }

.side .foot {
  margin-top: 26px;
  padding-top: 16px;
  border-top: 1px solid var(--line-soft);
  font-family: var(--mono);
  font-size: 10.5px;
  line-height: 1.9;
  color: var(--muted);
  letter-spacing: 0.03em;
}
.side .foot a { color: var(--muted); }
.side .foot a:hover { color: var(--gold); }

/* main column */
main {
  flex: 1;
  min-width: 0;
  padding: 0 56px 90px;
}
.page {
  max-width: var(--measure);
  margin: 0 auto;
}

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

header.chapter {
  padding: 76px 0 34px;
  margin-bottom: 44px;
  position: relative;
}
header.chapter::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 10px;
  background-image: url("assets/meander.svg");
  background-repeat: repeat-x;
  background-size: auto 10px;
  opacity: 0.5;
}
.kicker {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 18px;
}
.kicker .gn { font-family: var(--display); font-size: 13px; letter-spacing: 0.1em; }
header.chapter h1 {
  font-family: var(--display);
  font-weight: 400;
  font-size: clamp(34px, 5vw, 46px);
  line-height: 1.12;
  letter-spacing: 0.005em;
  color: var(--ink);
  margin: 0 0 14px;
}
header.chapter .lede {
  font-size: 19px;
  line-height: 1.62;
  color: var(--body);
  font-style: italic;
  max-width: 42rem;
}
header.chapter .lede b, header.chapter .lede strong { color: var(--ink); font-weight: 600; }

/* ---------- prose ---------- */

h2 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 27px;
  letter-spacing: 0.01em;
  color: var(--ink);
  margin: 58px 0 16px;
  padding-top: 8px;
}
h2 .sec {
  color: var(--gold-dim);
  font-size: 17px;
  margin-right: 12px;
  letter-spacing: 0.08em;
}
h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 18.5px;
  color: var(--ink);
  margin: 36px 0 10px;
}
h4 {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gold-dim);
  margin: 30px 0 8px;
}

p { margin: 0 0 16px; }
p b, p strong, li b, li strong { color: var(--ink); font-weight: 600; }
em { color: var(--body); }

a { color: var(--gold); text-decoration: none; border-bottom: 1px solid rgba(200,164,92,0.3); transition: border-color .14s ease, color .14s ease; }
a:hover { color: #e0c07f; border-bottom-color: #e0c07f; }

ul, ol { margin: 0 0 18px; padding-left: 26px; }
li { margin-bottom: 7px; }
li::marker { color: var(--gold-dim); }

hr {
  border: none;
  height: 1px;
  background: var(--line);
  margin: 44px 0;
}

/* inline code */
code {
  font-family: var(--mono);
  font-size: 0.82em;
  color: var(--river);
  background: var(--river-soft);
  border-radius: 4px;
  padding: 1.5px 5px;
  white-space: nowrap;
}
pre {
  background: var(--bg-deep);
  border: 1px solid var(--line-soft);
  border-left: 2px solid var(--gold-dim);
  border-radius: 8px;
  padding: 16px 20px;
  margin: 0 0 20px;
  overflow-x: auto;
  line-height: 1.6;
}
pre code {
  background: none;
  padding: 0;
  color: var(--body);
  font-size: 13px;
  white-space: pre;
}
pre .c  { color: var(--muted); }        /* comment */
pre .k  { color: var(--gold); }         /* keyword / emphasis */
pre .n  { color: var(--river); }        /* number / value */

/* source cross-reference chip */
code.src, a.src {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 1px 9px;
  white-space: nowrap;
}
p code.src { vertical-align: 1px; }
a.src { transition: color .14s ease, border-color .14s ease; }
a.src:hover { color: var(--gold); border-color: var(--gold-dim); }
tr:target td { background: var(--gold-soft); }
tr:target td:first-child { box-shadow: inset 2px 0 0 var(--gold); }

/* ---------- tables ---------- */

.tablewrap { overflow-x: auto; margin: 0 0 22px; }
table {
  border-collapse: collapse;
  width: 100%;
  font-size: 14.5px;
  line-height: 1.5;
}
th {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--gold-dim);
  text-align: left;
  padding: 8px 14px 8px 0;
  border-bottom: 1px solid var(--gold-dim);
}
td {
  padding: 9px 14px 9px 0;
  border-bottom: 1px solid var(--line-soft);
  vertical-align: top;
  color: var(--body);
}
td:first-child, th:first-child { padding-left: 2px; }
td b { color: var(--ink); }
td code { font-size: 12px; }
tr:hover td { background: rgba(234,229,214,0.015); }
table .num, td.num { font-family: var(--mono); font-size: 12.5px; color: var(--ink); white-space: nowrap; }

/* ---------- callouts ---------- */

.note, .why, .caution {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 16px 20px 12px;
  margin: 0 0 22px;
  font-size: 15.5px;
  background: var(--surface);
}
.note > :last-child, .why > :last-child, .caution > :last-child { margin-bottom: 4px; }
.note .lbl, .why .lbl, .caution .lbl {
  display: block;
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: 8px;
}
.why       { border-left: 2px solid var(--gold); }
.why .lbl  { color: var(--gold); }
.note      { border-left: 2px solid var(--river); }
.note .lbl { color: var(--river); }
.caution      { border-left: 2px solid var(--warn); }
.caution .lbl { color: var(--warn); }

/* definition cards (glossary) */
dl.gloss { margin: 0 0 24px; }
dl.gloss dt {
  font-family: var(--serif);
  font-weight: 600;
  color: var(--ink);
  margin-top: 18px;
}
dl.gloss dt code { font-size: 0.85em; }
dl.gloss dd { margin-left: 0; padding-left: 18px; border-left: 1px solid var(--line); margin-top: 4px; font-size: 15.5px; }

/* stat strip (hero figures) */
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: 10px;
  overflow: hidden;
  margin: 26px 0;
}
.stats .s { background: var(--surface); padding: 16px 18px 14px; }
.stats .v {
  font-family: var(--display);
  font-size: 24px;
  color: var(--ink);
  line-height: 1.15;
}
.stats .v small { font-size: 14px; color: var(--gold); }
.stats .k {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 6px;
}

/* figure/diagram blocks */
figure.diagram {
  margin: 26px 0 30px;
  border: 1px solid var(--line-soft);
  border-radius: 12px;
  background: var(--bg-deep);
  padding: 22px;
}
figure.diagram svg { width: 100%; height: auto; display: block; }
figure.diagram figcaption {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--muted);
  letter-spacing: 0.04em;
  margin-top: 14px;
  line-height: 1.6;
}
/* shared svg text styles */
figure.diagram text { font-family: var(--mono); }
figure.diagram .dt  { fill: var(--ink); font-size: 14px; font-family: var(--serif); font-weight: 600; }
figure.diagram .dk  { fill: var(--gold); font-size: 9.5px; letter-spacing: 0.08em; text-transform: uppercase; }
figure.diagram .dm  { fill: var(--muted); font-size: 10.5px; }
figure.diagram .box { fill: var(--surface); stroke: var(--line); stroke-width: 1.2; }
figure.diagram .edge { stroke: var(--muted); stroke-width: 1.3; fill: none; }
figure.diagram .edge.gold { stroke: var(--gold-dim); }
figure.diagram .edge.blue { stroke: var(--river); stroke-dasharray: 2 5; }
figure.diagram .elbl { fill: var(--muted); font-size: 9.5px; }

/* op ladder rows */
.ladder { border: 1px solid var(--line-soft); border-radius: 10px; overflow: hidden; margin: 0 0 24px; }
.ladder .rung {
  display: grid;
  grid-template-columns: 130px 150px 1fr;
  gap: 16px;
  padding: 13px 18px;
  border-bottom: 1px solid var(--line-soft);
  background: var(--surface);
  font-size: 14.5px;
}
.ladder .rung:last-child { border-bottom: none; }
.ladder .cr { font-family: var(--mono); font-size: 12px; color: var(--gold); align-self: center; }
.ladder .op { font-family: var(--serif); font-weight: 600; color: var(--ink); align-self: center; }
.ladder .op small { display: block; font-family: var(--mono); font-weight: 400; font-size: 10px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); margin-top: 2px; }
.ladder .fx { color: var(--body); align-self: center; font-size: 14px; }

/* prev / next pager */
nav.pager {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  margin-top: 72px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}
nav.pager a {
  border: none;
  max-width: 46%;
  text-decoration: none;
}
nav.pager .dir {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  display: block;
  margin-bottom: 4px;
}
nav.pager .ttl { font-family: var(--display); font-size: 19px; color: var(--ink); transition: color .14s ease; }
nav.pager a:hover .ttl { color: var(--gold); }
nav.pager .next { text-align: right; margin-left: auto; }

/* meander ornament */
.meander {
  height: 10px;
  background-image: url("assets/meander.svg");
  background-repeat: repeat-x;
  background-size: auto 10px;
  opacity: 0.55;
}

/* footnote-ish fine print */
.fine { font-size: 13.5px; color: var(--muted); line-height: 1.65; }
.fine code { font-size: 11.5px; }

/* anchor targets get breathing room under sticky-free layout */
:target { scroll-margin-top: 24px; }

h2 a.anchor, h3 a.anchor {
  border: none; color: var(--line);
  margin-left: 10px; font-size: 0.7em;
  opacity: 0; transition: opacity .12s ease;
}
h2:hover a.anchor, h3:hover a.anchor { opacity: 1; color: var(--gold-dim); }

/* ---------- responsive ---------- */

@media (max-width: 980px) {
  .wrap { display: block; }
  .side {
    position: static;
    width: auto;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--line-soft);
    padding: 22px 24px;
  }
  main { padding: 0 24px 60px; }
  header.chapter { padding-top: 40px; }
  .ladder .rung { grid-template-columns: 1fr; gap: 4px; }
}

@media print {
  .side, nav.pager { display: none; }
  body { background: #fff; color: #222; }
}