/* =========================================================================
   slotlabfa.com — design system
   Direction: research notebook. Paper-light surface, graph-paper texture,
   hairline rules, tabular monospace figures, meters and tables instead of
   marketing cards.
   ========================================================================= */

:root {
  --paper: #f7f8fa;
  --paper-2: #ffffff;
  --paper-3: #eef0f5;
  --rule: #d7dae3;
  --rule-2: #b9bec9;
  --ink: #12161c;
  --ink-2: #3d4451;
  --dim: #6b7280;
  --indigo: #4c4ce0;
  --indigo-soft: #edeeff;
  --teal: #12a594;
  --teal-soft: #e6f6f3;
  --amber: #b45309;
  --red: #c2334d;
  --r-s: 4px;
  --r-m: 8px;
  --wrap: 1180px;
  --fs-xs: 0.76rem;
  --fs-s: 0.875rem;
  --fs-b: 0.98rem;
  --fs-h3: 1.08rem;
  --fs-h2: 1.38rem;
  --fs-h1: clamp(1.6rem, 1.1rem + 2vw, 2.4rem);
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --font: system-ui, -apple-system, "SF Pro Text", "Segoe UI", Tahoma, sans-serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; } }

body {
  margin: 0;
  background: var(--paper);
  background-image: linear-gradient(var(--rule) 1px, transparent 1px), linear-gradient(90deg, var(--rule) 1px, transparent 1px);
  background-size: 28px 28px;
  background-position: -1px -1px;
  color: var(--ink);
  font-family: var(--font);
  font-size: var(--fs-b);
  line-height: 1.8;
  overflow-x: hidden;
}
body::before { content: ""; position: fixed; inset: 0; background: var(--paper); opacity: 0.86; pointer-events: none; z-index: -1; }

img, svg { max-width: 100%; height: auto; }
a { color: var(--indigo); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--indigo); outline-offset: 2px; }

h1, h2, h3, h4 { line-height: 1.35; margin: 0 0 0.55em; font-weight: 700; letter-spacing: -0.015em; }
h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }
p { margin: 0 0 1em; }
ul, ol { padding-inline-start: 1.3rem; margin: 0 0 1em; }
li { margin-bottom: 0.35em; }
code, .mono, .num { font-family: var(--mono); font-variant-numeric: tabular-nums; }
code { background: var(--paper-3); padding: 0.08em 0.32em; border-radius: 3px; font-size: 0.86em; }
table { border-collapse: collapse; width: 100%; }
.dim { color: var(--dim); }
.unk { color: var(--dim); font-family: var(--font); font-size: var(--fs-xs); font-style: italic; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }

.wrap { max-width: var(--wrap); margin-inline: auto; padding-inline: 1rem; }
.skip { position: absolute; inset-inline-start: -9999px; background: var(--indigo); color: #fff; padding: 0.5rem 1rem; z-index: 100; }
.skip:focus { inset-inline-start: 0; }

/* --------------------------------------------------------------- masthead */
.masthead { background: var(--paper-2); border-bottom: 1px solid var(--rule); position: sticky; top: 0; z-index: 50; }
.masthead-in { display: flex; align-items: center; gap: 1rem; min-height: 58px; flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 0.5rem; text-decoration: none; color: var(--ink); }
.brand span { display: flex; flex-direction: column; line-height: 1.2; }
.brand strong { font-size: 1rem; letter-spacing: -0.02em; }
.brand small { font-size: 0.66rem; color: var(--dim); }
.nav-toggle { margin-inline-start: auto; background: var(--paper-2); border: 1px solid var(--rule-2); border-radius: var(--r-s); padding: 0.35rem 0.75rem; font: inherit; font-size: var(--fs-s); cursor: pointer; color: var(--ink); }
.main-nav { display: none; width: 100%; }
.main-nav.is-open { display: block; }
.main-nav ul { list-style: none; margin: 0 0 0.6rem; padding: 0; display: flex; flex-direction: column; }
.main-nav a { display: block; padding: 0.45rem 0; font-size: var(--fs-s); text-decoration: none; color: var(--ink); border-bottom: 1px solid var(--paper-3); }
.main-nav a[aria-current="page"] { color: var(--indigo); font-weight: 700; }
@media (min-width: 940px) {
  .nav-toggle { display: none; }
  .main-nav { display: block !important; width: auto; margin-inline-start: auto; }
  .main-nav ul { flex-direction: row; gap: 1.1rem; margin: 0; }
  .main-nav a { border: 0; padding: 0; font-size: 0.83rem; white-space: nowrap; }
  .main-nav a:hover { color: var(--indigo); }
}

/* tool rail */
.rail { background: var(--paper-3); border-bottom: 1px solid var(--rule); }
.rail-in { display: flex; gap: 0.4rem; overflow-x: auto; padding-block: 0.4rem; scrollbar-width: thin; }
.rail-item { display: inline-flex; align-items: center; gap: 0.4rem; white-space: nowrap; font-size: var(--fs-xs); text-decoration: none; color: var(--ink); background: var(--paper-2); border: 1px solid var(--rule); border-radius: var(--r-s); padding: 0.28rem 0.6rem; }
.rail-item:hover { border-color: var(--indigo); color: var(--indigo); }
.rail-item.is-here { border-color: var(--indigo); background: var(--indigo-soft); color: var(--indigo); font-weight: 700; }
.rail-k { font-family: var(--mono); font-size: 0.66rem; background: var(--paper-3); border-radius: 2px; padding: 0 0.25rem; color: var(--dim); }
.rail-item.is-here .rail-k { background: #fff; color: var(--indigo); }

/* ------------------------------------------------------------- breadcrumb */
.crumbs { background: var(--paper-2); border-bottom: 1px solid var(--rule); }
.crumbs ol { list-style: none; display: flex; flex-wrap: wrap; gap: 0.3rem; padding: 0.35rem 0; margin: 0; font-size: var(--fs-xs); color: var(--dim); }
.crumbs li + li::before { content: "/"; margin-inline-end: 0.3rem; color: var(--rule-2); }
.crumbs a { color: var(--dim); text-decoration: none; }
.crumbs a:hover { color: var(--indigo); text-decoration: underline; }

/* ------------------------------------------------------------------ layout */
.sec { max-width: var(--wrap); margin-inline: auto; padding: 2rem 1rem; }
.sec + .sec { padding-top: 0.4rem; }
.lead { color: var(--ink-2); max-width: 68ch; }
.prose { max-width: 70ch; }
.prose h2 { margin-top: 1.8em; }
.prose h3 { margin-top: 1.4em; font-size: var(--fs-b); text-transform: none; color: var(--indigo); }

/* a section label, like a figure caption */
.label { display: inline-block; font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.08em; color: var(--dim); border: 1px solid var(--rule); border-radius: 2px; padding: 0.1rem 0.45rem; margin-bottom: 0.6rem; background: var(--paper-2); }

/* ------------------------------------------------------------------- hero */
.lab-hero { background: var(--paper-2); border-bottom: 1px solid var(--rule); }
.lab-hero-in { max-width: var(--wrap); margin-inline: auto; padding: 2rem 1rem 1.6rem; display: grid; gap: 1.6rem; }
.lab-hero h1 { margin-bottom: 0.4em; }
.lab-hero p { color: var(--ink-2); max-width: 60ch; }
@media (min-width: 900px) { .lab-hero-in { grid-template-columns: 1.1fr 0.9fr; align-items: start; } }

/* metric tiles */
.metrics { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1px; background: var(--rule); border: 1px solid var(--rule); }
@media (min-width: 620px) { .metrics.m4 { grid-template-columns: repeat(4, 1fr); } }
.metric { background: var(--paper-2); padding: 0.75rem 0.85rem; }
.metric b { display: block; font-family: var(--mono); font-size: 1.42rem; font-weight: 600; letter-spacing: -0.02em; color: var(--indigo); }
.metric span { display: block; font-size: var(--fs-xs); color: var(--dim); }
.metric.t b { color: var(--teal); }

/* ----------------------------------------------------------------- buttons */
.btn, .btn-2, .btn-cta {
  display: inline-flex; align-items: center; gap: 0.35rem; font: inherit; font-size: var(--fs-s);
  font-weight: 600; border-radius: var(--r-s); padding: 0.5rem 1rem; cursor: pointer;
  text-decoration: none; border: 1px solid transparent; min-height: 40px;
}
.btn, .btn-cta { background: var(--indigo); color: #fff; }
.btn:hover, .btn-cta:hover { background: #3b3bc4; text-decoration: none; }
.btn-2 { background: var(--paper-2); color: var(--ink); border-color: var(--rule-2); }
.btn-2:hover { border-color: var(--indigo); color: var(--indigo); text-decoration: none; }

/* ------------------------------------------------------------------ panels */
.panel { background: var(--paper-2); border: 1px solid var(--rule); border-radius: var(--r-m); padding: 1.1rem; }
.panel > h2, .panel > h3 { margin-top: 0; }
.panel-cap { font-size: var(--fs-xs); color: var(--dim); border-top: 1px solid var(--rule); margin-top: 0.9rem; padding-top: 0.6rem; }
.cols { display: grid; gap: 1rem; }
@media (min-width: 760px) { .cols.c2 { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1000px) { .cols.c3 { grid-template-columns: repeat(3, 1fr); } }

/* ------------------------------------------------------------------ tables */
.tablewrap { overflow-x: auto; border: 1px solid var(--rule); background: var(--paper-2); }
.dtable { font-size: var(--fs-s); min-width: 640px; }
.dtable caption { text-align: start; font-size: var(--fs-xs); color: var(--dim); padding: 0.5rem 0.7rem; border-bottom: 1px solid var(--rule); }
.dtable th, .dtable td { padding: 0.5rem 0.7rem; text-align: start; border-bottom: 1px solid var(--paper-3); }
.dtable thead th { background: var(--paper-3); font-size: var(--fs-xs); color: var(--dim); font-weight: 600; border-bottom: 1px solid var(--rule); }
.dtable tbody tr:hover { background: var(--indigo-soft); }
.dtable td.n, .dtable th.n { font-family: var(--mono); font-variant-numeric: tabular-nums; text-align: end; }
.dtable tfoot td { font-size: var(--fs-xs); color: var(--dim); }

/* inline bar meter inside a table cell */
.mini { display: flex; align-items: center; gap: 0.4rem; }
.mini-bar { flex: 1; height: 6px; min-width: 44px; background: var(--paper-3); border-radius: 2px; overflow: hidden; }
.mini-bar i { display: block; height: 100%; background: var(--indigo); }
.mini-bar.t i { background: var(--teal); }
.mini-v { font-family: var(--mono); font-size: var(--fs-xs); min-width: 2.2rem; text-align: end; }

/* -------------------------------------------------------------- dossier */
.dossier { border: 1px solid var(--rule); background: var(--paper-2); }
.dossier-head { display: flex; gap: 0.9rem; align-items: center; padding: 1rem; border-bottom: 1px solid var(--rule); background: var(--paper-3); flex-wrap: wrap; }
.dossier-head img { background: #fff; border: 1px solid var(--rule); padding: 4px 6px; max-height: 42px; width: auto; }
.dossier-id { font-family: var(--mono); font-size: var(--fs-xs); color: var(--dim); }
.dossier-body { padding: 1rem; }
.brand-logo { background: #fff; border: 1px solid var(--rule); padding: 4px 6px; max-height: 42px; width: auto; object-fit: contain; }

.kv { display: grid; gap: 0; margin: 0; font-size: var(--fs-s); }
.kv > div { display: flex; justify-content: space-between; gap: 1rem; padding: 0.35rem 0; border-bottom: 1px dotted var(--rule); }
.kv dt { color: var(--dim); margin: 0; }
.kv dd { margin: 0; font-family: var(--mono); font-variant-numeric: tabular-nums; }

/* ------------------------------------------------------------------- tools */
.tool { background: var(--paper-2); border: 1px solid var(--rule-2); border-radius: var(--r-m); padding: 1.1rem; }
.tool h3 { margin-top: 0; }
.tool-grid { display: grid; gap: 0.8rem; }
@media (min-width: 700px) { .tool-grid.tg2 { grid-template-columns: repeat(2, 1fr); } }
.field { display: grid; gap: 0.25rem; margin-bottom: 0.7rem; }
.field label { font-size: var(--fs-s); font-weight: 600; }
.field .hint { font-size: var(--fs-xs); color: var(--dim); }
.field input[type="number"], .field input[type="text"], .field select, .field textarea {
  font: inherit; font-family: var(--mono); font-size: var(--fs-s); background: var(--paper);
  border: 1px solid var(--rule-2); border-radius: var(--r-s); padding: 0.5rem 0.6rem; width: 100%; color: var(--ink);
}
.field textarea { font-family: var(--font); resize: vertical; }
.field input[type="range"] { width: 100%; accent-color: var(--indigo); }
.out { background: var(--paper-3); border: 1px solid var(--rule); border-radius: var(--r-s); padding: 0.8rem 0.9rem; margin-top: 0.6rem; }
.out-row { display: flex; justify-content: space-between; gap: 1rem; padding: 0.25rem 0; border-bottom: 1px dotted var(--rule-2); font-size: var(--fs-s); }
.out-row:last-child { border-bottom: 0; }
.out-row b { font-family: var(--mono); font-variant-numeric: tabular-nums; }
.out-note { font-size: var(--fs-xs); color: var(--dim); margin: 0.6rem 0 0; }

/* volatility / distribution bars */
.dist { display: grid; gap: 0.35rem; }
.dist-row { display: grid; grid-template-columns: 7rem 1fr 3.4rem; gap: 0.5rem; align-items: center; font-size: var(--fs-xs); }
.dist-bar { height: 14px; background: var(--paper-3); border: 1px solid var(--rule); position: relative; }
.dist-bar i { position: absolute; inset-block: 0; inset-inline-start: 0; background: var(--indigo); opacity: 0.85; }
.dist-row.t .dist-bar i { background: var(--teal); }
.dist-v { font-family: var(--mono); text-align: end; }

/* payline explorer grid */
.pl-explorer { display: grid; gap: 1rem; }
@media (min-width: 780px) { .pl-explorer { grid-template-columns: 1fr 260px; } }
.pl-board { display: grid; grid-template-columns: repeat(5, 1fr); gap: 4px; background: var(--paper-3); border: 1px solid var(--rule); padding: 6px; }
.pl-cell { aspect-ratio: 1; background: var(--paper-2); border: 1px solid var(--rule); display: grid; place-items: center; font-family: var(--mono); font-size: 0.7rem; color: var(--dim); }
.pl-cell.on { background: var(--indigo); border-color: var(--indigo); color: #fff; }
.pl-list { max-height: 320px; overflow-y: auto; border: 1px solid var(--rule); background: var(--paper-2); }
.pl-list button { display: block; width: 100%; text-align: start; font: inherit; font-size: var(--fs-s); background: none; border: 0; border-bottom: 1px solid var(--paper-3); padding: 0.45rem 0.7rem; cursor: pointer; color: var(--ink); }
.pl-list button:hover { background: var(--indigo-soft); }
.pl-list button[aria-pressed="true"] { background: var(--indigo); color: #fff; font-weight: 700; }

/* -------------------------------------------------------------------- note */
.note { border-inline-start: 3px solid var(--indigo); background: var(--paper-2); border: 1px solid var(--rule); border-inline-start-width: 3px; padding: 0.9rem 1rem; margin: 1.2rem 0; font-size: var(--fs-s); }
.note h3 { margin-top: 0; font-size: var(--fs-b); color: var(--indigo); }
.note.warn { border-inline-start-color: var(--red); }
.note.warn h3 { color: var(--red); }
.note p:last-child { margin-bottom: 0; }

/* ------------------------------------------------------------------- faq */
.qs { display: grid; gap: 0; border: 1px solid var(--rule); background: var(--paper-2); }
.q { border-bottom: 1px solid var(--rule); }
.q:last-child { border-bottom: 0; }
.q summary { cursor: pointer; padding: 0.7rem 0.9rem; list-style: none; display: flex; gap: 0.5rem; align-items: center; }
.q summary::-webkit-details-marker { display: none; }
.q summary::after { content: "▾"; margin-inline-start: auto; color: var(--dim); }
.q[open] summary::after { content: "▴"; }
.q summary h3 { margin: 0; font-size: var(--fs-s); font-weight: 600; }
.q .a { padding: 0 0.9rem 0.9rem; font-size: var(--fs-s); color: var(--ink-2); }
.q .a p:last-child { margin-bottom: 0; }

/* --------------------------------------------------------------- see-also */
.seealso { border-top: 1px solid var(--rule); padding-top: 1rem; }
.seealso ul { list-style: none; padding: 0; display: grid; gap: 0.5rem; }
@media (min-width: 700px) { .seealso ul { grid-template-columns: repeat(2, 1fr); } }
.seealso a { display: block; background: var(--paper-2); border: 1px solid var(--rule); padding: 0.6rem 0.8rem; text-decoration: none; color: var(--ink); }
.seealso a:hover { border-color: var(--indigo); }
.seealso strong { display: block; font-size: var(--fs-s); color: var(--indigo); }
.seealso span { font-size: var(--fs-xs); color: var(--dim); }

/* --------------------------------------------------------------- comments */
.comments { max-width: 820px; }
.cmt { border: 1px solid var(--rule); background: var(--paper-2); padding: 0.7rem 0.9rem; margin-bottom: 0.5rem; }
.cmt-head { display: flex; gap: 0.6rem; align-items: baseline; flex-wrap: wrap; font-size: var(--fs-s); }
.cmt-head strong { font-weight: 700; }
.cmt-head time { margin-inline-start: auto; font-family: var(--mono); font-size: var(--fs-xs); color: var(--dim); }
.cmt-topic { font-size: var(--fs-xs); background: var(--paper-3); border: 1px solid var(--rule); padding: 0 0.4rem; color: var(--dim); }
.cmt-brand { font-size: var(--fs-xs); color: var(--dim); }
.cmt-body { margin: 0.3rem 0 0; font-size: var(--fs-s); color: var(--ink-2); }
.cmt.is-pending { border-style: dashed; border-color: var(--teal); background: var(--teal-soft); }
.cmt-pending { font-size: var(--fs-xs); color: var(--teal); margin: 0.3rem 0 0; }
.stars { color: var(--amber); letter-spacing: 1px; }
.cmt-form { border: 1px solid var(--rule-2); background: var(--paper-2); padding: 1rem; margin-top: 1.2rem; }
.cmt-form h3 { margin-top: 0; }
.f-msg { font-size: var(--fs-s); color: var(--teal); min-height: 1.2em; margin: 0.5rem 0 0; }

/* ------------------------------------------------------------------ footer */
.site-foot { background: var(--paper-2); border-top: 1px solid var(--rule); margin-top: 2.6rem; padding: 1.8rem 0 1.2rem; }
.foot-grid { display: grid; gap: 1.2rem; grid-template-columns: repeat(2, 1fr); }
@media (min-width: 780px) { .foot-grid { grid-template-columns: repeat(4, 1fr); } }
.foot-col h2 { font-size: var(--fs-xs); text-transform: uppercase; letter-spacing: 0.06em; color: var(--dim); margin-bottom: 0.5rem; }
.foot-col ul { list-style: none; padding: 0; margin: 0; }
.foot-col li { margin-bottom: 0.25rem; }
.foot-col a { font-size: var(--fs-xs); color: var(--ink-2); text-decoration: none; }
.foot-col a:hover { color: var(--indigo); text-decoration: underline; }
.foot-note { border-top: 1px solid var(--rule); margin-top: 1.4rem; padding-top: 0.9rem; font-size: var(--fs-xs); color: var(--dim); }
.foot-note p { margin-bottom: 0.4em; }
.foot-updated { font-family: var(--mono); }

/* -------------------------------------------------------------------- 404 */
.e404 { text-align: center; padding: 3.5rem 1rem; }
.e404 .code { font-family: var(--mono); font-size: 4rem; color: var(--indigo); margin: 0; }