/* FreX — editorial design system */
:root, [data-theme="light"] {
  --paper: #f7f4ec;
  --paper-2: #efeadc;
  --paper-3: #e6dfcc;
  --ink: #1a1815;
  --ink-2: #3a362f;
  --ink-3: #6b6459;
  --ink-4: #9a9487;
  --rule: #d6cfbd;
  --rule-soft: #e8e1cf;
  --accent: #b5431c;        /* burnt sienna */
  --accent-ink: #8c3415;
  --accent-wash: #f0dfd2;
  --cool: #2f4a5c;          /* slate teal */
  --cool-wash: #dce5ea;
  --ok: #2d5a36;
  --warn: #8a5a10;
  --danger: #8c2318;
  --code-bg: #efeadc;
  --code-border: #d6cfbd;
}
[data-theme="dark"] {
  --paper: #13110e;
  --paper-2: #1b1813;
  --paper-3: #23201a;
  --ink: #f1ece0;
  --ink-2: #d7d1c2;
  --ink-3: #a8a293;
  --ink-4: #6d6758;
  --rule: #2b2720;
  --rule-soft: #201d17;
  --accent: #e07048;
  --accent-ink: #e88762;
  --accent-wash: #2a1d17;
  --cool: #89a7b8;
  --cool-wash: #1a2128;
  --ok: #7cb388;
  --warn: #dcaa4a;
  --danger: #d57866;
  --code-bg: #1b1813;
  --code-border: #2b2720;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  background: var(--paper); color: var(--ink);
  font-family: 'Inter', -apple-system, system-ui, sans-serif;
  font-size: 16px; line-height: 1.6;
  font-feature-settings: 'ss01', 'cv11';
}
img, svg { display: block; max-width: 100%; }
a { color: var(--accent-ink); text-decoration: none; text-underline-offset: 3px; }
a:hover { text-decoration: underline; text-decoration-thickness: 1px; }
button { font: inherit; color: inherit; background: none; border: none; cursor: pointer; }
::selection { background: var(--accent-wash); color: var(--ink); }
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-thumb { background: var(--rule); }
::-webkit-scrollbar-track { background: var(--paper); }

.font-serif { font-family: 'Instrument Serif', Georgia, serif; font-weight: 400; letter-spacing: -0.01em; }
.font-mono { font-family: 'JetBrains Mono', ui-monospace, monospace; }
.eyebrow {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px; font-weight: 500;
  letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--ink-3);
}
.eyebrow.accent { color: var(--accent-ink); }

/* ─── Masthead ─── */
.masthead {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--paper) 92%, transparent);
  backdrop-filter: saturate(130%) blur(10px);
  border-bottom: 1px solid var(--rule);
}
.masthead-inner {
  max-width: 1180px; margin: 0 auto;
  padding: 14px 28px;
  display: flex; align-items: center; gap: 28px;
}
.mh-brand {
  display: flex; align-items: baseline; gap: 10px;
  text-decoration: none; color: var(--ink);
}
.mh-brand:hover { text-decoration: none; }
.mh-mark {
  font-family: 'Instrument Serif', serif; font-size: 28px;
  letter-spacing: -0.02em; line-height: 1;
}
.mh-mark em { font-style: italic; color: var(--accent-ink); }
.mh-tag {
  font-family: 'JetBrains Mono', monospace; font-size: 10px;
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-4);
  border-left: 1px solid var(--rule); padding-left: 10px;
}
.mh-nav { margin-left: auto; display: flex; align-items: center; gap: 4px; }
.mh-nav a {
  padding: 8px 14px; font-size: 13.5px; color: var(--ink-3);
  text-decoration: none; border-radius: 2px;
  font-weight: 450;
}
.mh-nav a:hover { color: var(--ink); text-decoration: none; background: var(--paper-2); }
.mh-nav a.active { color: var(--ink); font-weight: 600; }
.mh-nav a.active::after {
  content: ''; display: block; height: 2px; background: var(--accent); margin-top: 3px;
}
.mh-cta {
  margin-left: 8px; padding: 8px 14px !important;
  background: var(--ink); color: var(--paper) !important;
  border-radius: 2px; font-weight: 500 !important;
  white-space: nowrap; flex-shrink: 0;
}
.mh-nav a { flex-shrink: 0; }
.mh-cta:hover { background: var(--accent); color: var(--paper) !important; }
.mh-theme {
  margin-left: 6px; padding: 8px; color: var(--ink-3);
  border-radius: 2px; display: flex; align-items: center;
}
.mh-theme:hover { color: var(--ink); background: var(--paper-2); }

@media (max-width: 980px) {
  .mh-tag { display: none; }
  .mh-nav { gap: 2px; }
  .mh-nav a { padding: 6px 10px; font-size: 12.5px; }
}
@media (max-width: 720px) {
  .mh-nav a:not(.mh-cta):not(.active) { display: none; }
  .mh-nav a.mh-cta { padding: 6px 10px !important; }
}

/* ─── Layout primitives ─── */
.shell { max-width: 1180px; margin: 0 auto; padding: 0 28px; }
.narrow { max-width: 760px; margin: 0 auto; padding: 0 28px; }
.rule { height: 1px; background: var(--rule); border: 0; }
.rule-thick { height: 1px; background: var(--ink); border: 0; }

/* ─── Typography ─── */
h1, h2, h3, h4 { font-family: 'Instrument Serif', Georgia, serif; font-weight: 400; color: var(--ink); letter-spacing: -0.015em; }
h1 { font-size: clamp(2.8rem, 6.4vw, 5.4rem); line-height: 1.08; }
h2 { font-size: clamp(2rem, 3.6vw, 3rem); line-height: 1.08; }
h3 { font-size: 1.6rem; line-height: 1.15; }
h4 { font-size: 1.2rem; line-height: 1.2; }
h1 em, h2 em, h3 em { font-style: italic; color: var(--accent-ink); }
p { color: var(--ink-2); }
p.lead { font-size: 1.2rem; line-height: 1.55; color: var(--ink-2); max-width: 60ch; }

/* ─── Buttons ─── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 22px; font-size: 14.5px; font-weight: 500;
  border-radius: 2px; text-decoration: none;
  transition: transform .15s ease, background .15s ease, color .15s ease;
  white-space: nowrap;
}
.btn:hover { text-decoration: none; }
.btn-ink { background: var(--ink); color: var(--paper); }
.btn-ink:hover { background: var(--accent); color: var(--paper); }
.btn-ghost { background: transparent; color: var(--ink); border: 1px solid var(--ink); }
.btn-ghost:hover { background: var(--ink); color: var(--paper); }
.btn-accent { background: var(--accent); color: #fff; }
.btn-accent:hover { background: var(--accent-ink); color: #fff; }

/* ─── Editorial article layout ─── */
article.doc { padding: 56px 0 120px; }
article.doc .doc-grid {
  display: grid;
  grid-template-columns: 200px minmax(0, 1fr);
  gap: 56px;
  max-width: 1060px; margin: 0 auto; padding: 0 28px;
}
.doc-rail { position: sticky; top: 88px; align-self: start; }
.doc-rail-label { font-family: 'JetBrains Mono', monospace; font-size: 10px; letter-spacing: 0.18em; text-transform: uppercase; color: var(--ink-4); margin-bottom: 14px; }
.doc-rail ol { list-style: none; counter-reset: rc; display: flex; flex-direction: column; gap: 2px; }
.doc-rail li { counter-increment: rc; }
.doc-rail a {
  display: grid; grid-template-columns: 28px 1fr; gap: 6px; align-items: baseline;
  padding: 5px 0; font-size: 13px; color: var(--ink-3); text-decoration: none;
}
.doc-rail a::before {
  content: counter(rc, decimal-leading-zero);
  font-family: 'JetBrains Mono', monospace; font-size: 10.5px; color: var(--ink-4);
}
.doc-rail a:hover { color: var(--ink); text-decoration: none; }

.doc-body { min-width: 0; max-width: 680px; }
.doc-body section { margin-bottom: 72px; scroll-margin-top: 80px; }
.doc-body section h2 {
  font-size: 2.2rem; line-height: 1.1; margin-bottom: 8px;
  padding-bottom: 14px; border-bottom: 1px solid var(--rule);
}
.doc-body section .sec-num {
  font-family: 'JetBrains Mono', monospace; font-size: 11px;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent-ink);
  margin-bottom: 8px; display: block;
}
.doc-body h3 { font-size: 1.4rem; margin: 32px 0 10px; color: var(--ink); }
.doc-body p { margin-bottom: 14px; max-width: 62ch; color: var(--ink-2); }
.doc-body p:last-child { margin-bottom: 0; }
.doc-body ul, .doc-body ol { margin: 12px 0 18px 1.1em; color: var(--ink-2); }
.doc-body li { margin-bottom: 6px; }
code.inline, p code, li code {
  font-family: 'JetBrains Mono', monospace; font-size: .88em;
  background: var(--code-bg); border: 1px solid var(--code-border);
  color: var(--accent-ink);
  padding: 1px 6px; border-radius: 2px;
}

@media (max-width: 900px) {
  article.doc .doc-grid { grid-template-columns: 1fr; gap: 32px; }
  .doc-rail { position: static; }
}

/* ─── Code block ─── */
.code {
  background: var(--code-bg); border: 1px solid var(--code-border);
  border-left: 2px solid var(--ink); margin: 14px 0;
}
.code-bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 14px; border-bottom: 1px solid var(--code-border);
  font-family: 'JetBrains Mono', monospace; font-size: 10.5px;
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-4);
}
.code-copy {
  font-family: 'JetBrains Mono', monospace; font-size: 10.5px;
  letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-3);
  padding: 2px 6px; border: 1px solid var(--rule); border-radius: 2px;
}
.code-copy:hover { color: var(--accent-ink); border-color: var(--accent); }
.code-copy.copied { color: var(--ok); border-color: var(--ok); }
.code pre {
  padding: 14px 16px; font-family: 'JetBrains Mono', monospace;
  font-size: 13px; line-height: 1.65; color: var(--ink);
  overflow-x: auto; white-space: pre;
}

/* ─── Callouts ─── */
.note {
  border-left: 2px solid var(--accent);
  background: var(--accent-wash);
  padding: 14px 18px; margin: 18px 0;
  font-size: 14.5px; color: var(--ink);
}
.note.warn { border-color: var(--warn); background: color-mix(in oklab, var(--warn) 12%, var(--paper)); }
.note.danger { border-color: var(--danger); background: color-mix(in oklab, var(--danger) 10%, var(--paper)); }
.note .note-label {
  font-family: 'JetBrains Mono', monospace; font-size: 10.5px;
  letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--accent-ink); margin-bottom: 4px; display: block;
}
.note.warn .note-label { color: var(--warn); }
.note.danger .note-label { color: var(--danger); }

/* ─── Steps (numbered) ─── */
ol.steps { list-style: none; margin: 14px 0; counter-reset: s; padding: 0; }
ol.steps > li {
  counter-increment: s;
  display: grid; grid-template-columns: 36px 1fr; gap: 16px;
  padding: 18px 0; border-bottom: 1px solid var(--rule-soft);
}
ol.steps > li:last-child { border-bottom: 0; }
ol.steps > li::before {
  content: counter(s, decimal-leading-zero);
  font-family: 'Instrument Serif', serif; font-size: 1.8rem;
  color: var(--accent-ink); line-height: 1; padding-top: 2px;
}
ol.steps .step-title { font-family: 'Instrument Serif', serif; font-size: 1.25rem; color: var(--ink); margin-bottom: 4px; }
ol.steps .step-body p { font-size: 14.5px; margin-bottom: 8px; }

/* ─── Footer ─── */
.colophon {
  margin-top: 80px;
  border-top: 1px solid var(--rule);
  padding: 36px 28px 48px;
}
.colophon-inner { max-width: 1180px; margin: 0 auto; display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 32px; }
.colophon-brand { font-family: 'Instrument Serif', serif; font-size: 28px; letter-spacing: -0.02em; }
.colophon-brand em { font-style: italic; color: var(--accent-ink); }
.colophon-desc { font-size: 13px; color: var(--ink-3); margin-top: 6px; max-width: 36ch; }
.colophon h5 { font-family: 'JetBrains Mono', monospace; font-size: 10.5px; font-weight: 500; letter-spacing: 0.16em; text-transform: uppercase; color: var(--ink-4); margin-bottom: 10px; }
.colophon ul { list-style: none; display: flex; flex-direction: column; gap: 6px; }
.colophon ul a { font-size: 13.5px; color: var(--ink-2); }
.colophon ul a:hover { color: var(--accent-ink); }
.colophon-bottom {
  max-width: 1180px; margin: 28px auto 0;
  padding-top: 20px; border-top: 1px solid var(--rule-soft);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
  font-family: 'JetBrains Mono', monospace; font-size: 10.5px;
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-4);
}
@media (max-width: 760px) { .colophon-inner { grid-template-columns: 1fr 1fr; } .colophon-brand-block { grid-column: 1 / -1; } }

/* Animate — hidden state only applies when JS is running (see frex.js adds .js to <html>).
   Without this gate, no-JS users and screenshot scrapers see permanent blank sections. */
.anim { opacity: 1; transform: none; transition: opacity .6s ease, transform .6s ease; }
.js .anim { opacity: 0; transform: translateY(10px); }
.js .anim.in { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
  .js .anim, .js .anim.in { opacity: 1; transform: none; transition: none; }
}