/* ==========================================================================
   Fathom — "The Engineering Notebook" identity
   Light graph paper · semantic multi-hue accents · monospace display voice
   See SPEC.md for the token rationale. One meaning per hue, site-wide:
   blue = command/keyword/interactive · green = success/string/addition
   amber = warning · red = error/deletion. Structure stays neutral.
   ========================================================================== */

:root {
  /* paper + structure */
  --paper:        #FAFAF6;
  --paper-raised: #FFFFFD;
  --grid:         #ECEBE4;
  --rule:         #DBD9CE;
  --rule-soft:    #E7E5DB;
  --ghost:        #D8D6C9;   /* oversized margin numerals, decorative only */

  /* ink */
  --ink:   #1A1D23;
  --ink-2: #454A53;
  --ink-3: #6B7079;

  /* semantic accents — graphic grade (large elements, washes) */
  --blue:  #2F6FED;
  --green: #2E8B57;
  --amber: #D97706;
  --red:   #D64545;

  /* semantic accents — text grade (AA on paper at body sizes) */
  --blue-ink:  #2257C9;
  --green-ink: #25714A;
  --amber-ink: #91520A;
  --red-ink:   #B23A3A;

  /* semantic washes (diff rows, badges, CTA field) */
  --blue-wash:  #EBF1FD;
  --green-wash: #E9F3EC;
  --amber-wash: #FAF0DF;
  --red-wash:   #FAEAE8;

  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --sans: 'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', Helvetica, Arial, sans-serif;

  --maxw: 1080px;
  --shadow: 4px 4px 0 rgba(26, 29, 35, 0.08);
}

/* --------------------------------------------------------------------------
   Base
   -------------------------------------------------------------------------- */

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font: 400 1.0625rem/1.65 var(--sans);
  color: var(--ink);
  background-color: var(--paper);
  /* the 8px graph-paper grid — the page IS the notebook */
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 8px 8px;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--blue-wash); color: var(--ink); }

img, svg { max-width: 100%; height: auto; }

p { margin: 0 0 1em; }
p:last-child { margin-bottom: 0; }

a { color: var(--blue-ink); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible {
  outline: 2.5px solid var(--blue);
  outline-offset: 2px;
  border-radius: 2px;
}

h1, h2, h3, h4 {
  font-family: var(--mono);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 0.55em;
}

h1 { font-size: clamp(2.05rem, 4.6vw, 3.1rem); font-weight: 800; line-height: 1.12; letter-spacing: -0.03em; }
h2 { font-size: clamp(1.35rem, 2.6vw, 1.8rem); font-weight: 700; }
h3 { font-size: 1.05rem; font-weight: 700; }

code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: #F2F1EA;
  border: 1px solid var(--rule-soft);
  border-radius: 3px;
  padding: 1px 5px;
}

.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;
}

.skip {
  position: absolute; left: 12px; top: -48px; z-index: 100;
  background: var(--ink); color: #fff;
  font: 600 0.8rem var(--mono);
  padding: 10px 14px; border-radius: 0 0 4px 4px;
  transition: none;
}
.skip:focus { top: 0; }

.wrap { max-width: var(--maxw); margin-inline: auto; padding-inline: 24px; }

.eyebrow {
  display: inline-block;
  font: 600 0.72rem var(--mono);
  letter-spacing: 0.05em;
  color: var(--ink-3);
  margin-bottom: 14px;
}
.eyebrow::before { content: '// '; color: var(--blue-ink); }

.lede { font-size: 1.1rem; color: var(--ink-2); max-width: 56ch; }

/* --------------------------------------------------------------------------
   Header
   -------------------------------------------------------------------------- */

.site-head {
  position: sticky; top: 0; z-index: 50;
  background: rgba(250, 250, 246, 0.94);
  backdrop-filter: blur(5px);
  border-bottom: 2px solid var(--rule);
}

.nav {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 8px 20px;
  min-height: 62px; padding-block: 10px;
}

.brand {
  display: inline-flex; align-items: center; gap: 9px;
  font: 800 1.2rem var(--mono); letter-spacing: -0.02em;
  color: var(--ink); text-decoration: none;
}
.brand:hover { color: var(--blue-ink); }

.nav-links {
  list-style: none; margin: 0; padding: 0;
  display: flex; flex-wrap: wrap; align-items: center; gap: 2px 20px;
  font: 500 0.85rem var(--mono);
}
.nav-links a:not(.btn) {
  color: var(--ink-2); text-decoration: none;
  padding: 6px 1px; border-bottom: 2px solid transparent;
}
.nav-links a:not(.btn):hover { color: var(--blue-ink); border-bottom-color: var(--blue); }
.nav-links a[aria-current="page"] { color: var(--ink); font-weight: 700; border-bottom-color: var(--blue); }

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */

.btn {
  display: inline-block;
  font: 600 0.85rem/1 var(--mono);
  padding: 12px 20px;
  border-radius: 4px;
  border: 1.5px solid transparent;
  text-decoration: none;
  cursor: pointer;
}
.btn-primary { background: var(--blue-ink); border-color: var(--blue-ink); color: #fff; }
.btn-primary:hover { background: var(--ink); border-color: var(--ink); }
.btn-ghost { background: transparent; border-color: var(--ink); color: var(--ink); }
.btn-ghost:hover { background: var(--ink); color: var(--paper); }

/* --------------------------------------------------------------------------
   Notebook grid — margin column + main column
   -------------------------------------------------------------------------- */

.nb {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr);
  column-gap: 40px;
}
/* grid items default to min-width:auto — pre/terminal content must never
   stretch the page; scroll containers need this to actually contain */
.nb > *, .hero-grid > *, .contact-cols > * { min-width: 0; }

.nb-margin {
  text-align: right;
  border-right: 3px double var(--rule);
  padding: 4px 22px 4px 0;
}

.m-stick { position: sticky; top: 96px; display: grid; gap: 8px; justify-items: end; }

.m-path {
  font: 500 0.72rem var(--mono);
  color: var(--ink-3);
  word-break: break-all;
}

.m-ln {
  font: 800 1.9rem/1 var(--mono);
  color: var(--ghost);
  letter-spacing: -0.04em;
}

.m-note {
  font: italic 400 0.85rem/1.5 var(--sans);
  color: var(--ink-2);
  max-width: 22ch;
}

.m-date { font: 500 0.75rem var(--mono); color: var(--ink-2); }
.m-by   { font: italic 400 0.8rem var(--sans); color: var(--ink-3); }

/* --------------------------------------------------------------------------
   Sections
   -------------------------------------------------------------------------- */

.sec { padding-block: 76px; }
.sec-tight { padding-block: 48px; }
.ruled-top { border-top: 2px solid var(--rule); }

/* --------------------------------------------------------------------------
   Hero
   -------------------------------------------------------------------------- */

.hero { padding: 72px 0 88px; }

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 10fr) minmax(0, 11fr);
  gap: 56px;
  align-items: start;
}

.hero h1 { margin-bottom: 20px; }

.hero-ctas { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }

.hero-meta { margin-top: 20px; font: 500 0.76rem/1.8 var(--mono); color: var(--ink-3); }

/* --------------------------------------------------------------------------
   Terminal — the signature artifact. Paper, not a dark window.
   -------------------------------------------------------------------------- */

.term {
  margin: 0;
  background: var(--paper-raised);
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  box-shadow: var(--shadow);
  overflow: hidden;
}

.term-bar {
  display: flex; align-items: center; gap: 12px;
  padding: 9px 14px;
  border-bottom: 1.5px solid var(--ink);
  background: var(--paper);
  font: 500 0.72rem var(--mono);
  color: var(--ink-3);
}

.term-dots { display: inline-flex; gap: 5px; }
.term-dots i {
  width: 9px; height: 9px;
  border: 1.5px solid var(--ink-3);
  border-radius: 50%;
  background: transparent;
}

.term-body {
  margin: 0;
  padding: 16px 18px;
  overflow-x: auto;
  font: 400 0.8125rem/1.62 var(--mono);
  color: var(--ink);
  white-space: normal; /* lines carry their own pre */
}

.tl { display: block; white-space: pre; min-height: 1.62em; }
.tl .p { color: var(--blue-ink); font-weight: 700; }
.tl.cmd { font-weight: 600; }
.tl.dim { color: var(--ink-3); }

.ok   { color: var(--green-ink); }
.warn { color: var(--amber-ink); }
.err  { color: var(--red-ink); }

.tl.add { color: var(--green-ink); background: var(--green-wash); }
.tl.del { color: var(--red-ink);  background: var(--red-wash); }

.caret {
  display: inline-block;
  width: 0.55em; height: 1.05em;
  background: var(--ink);
  vertical-align: text-bottom;
  margin-left: 1px;
}

.term-sm .term-body { font-size: 0.78rem; }

/* --------------------------------------------------------------------------
   Code blocks (non-terminal)
   -------------------------------------------------------------------------- */

.code {
  margin: 20px 0;
  background: var(--paper-raised);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--blue);
  border-radius: 4px;
  padding: 15px 17px;
  overflow-x: auto;
  font: 400 0.8125rem/1.6 var(--mono);
  color: var(--ink);
}
.code code {
  display: block;
  white-space: pre; /* authored line breaks are real; block scrolls, never wraps */
  background: none; border: 0; padding: 0; font-size: 1em;
}
.code .c { color: var(--ink-3); font-style: italic; }  /* comment */
.code .s { color: var(--green-ink); }                  /* string */
.code .k { color: var(--blue-ink); }                   /* keyword */

.code-cap {
  font: 500 0.72rem var(--mono);
  color: var(--ink-3);
  margin: -14px 0 20px;
}

/* --------------------------------------------------------------------------
   Property cells — graph-cell grid, shared ink borders
   -------------------------------------------------------------------------- */

.prop-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(235px, 1fr));
  gap: 1.5px;
  background: var(--ink);
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.prop { background: var(--paper-raised); padding: 24px 22px; }
.prop .m-path { display: block; margin-bottom: 10px; }
.prop h3 { margin: 0 0 8px; font-size: 0.98rem; }
.prop p { margin: 0; font-size: 0.92rem; line-height: 1.6; color: var(--ink-2); }

/* --------------------------------------------------------------------------
   Steps (index)
   -------------------------------------------------------------------------- */

.step { padding-block: 42px; }
.step + .step { border-top: 2px solid var(--rule-soft); }
.step h3 { font-size: 1.2rem; margin-bottom: 10px; }
.step p { color: var(--ink-2); max-width: 62ch; }

/* --------------------------------------------------------------------------
   CTA band — blue field: interactive is blue's one job
   -------------------------------------------------------------------------- */

.cta-band {
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--blue-wash);
  box-shadow: var(--shadow);
  padding: 38px 36px;
  display: flex; flex-wrap: wrap; align-items: center;
  justify-content: space-between; gap: 22px;
}
.cta-band h2 { margin: 0 0 6px; }
.cta-band p { margin: 0; color: var(--ink-2); }

/* --------------------------------------------------------------------------
   Tables — spec-sheet voice (pricing, flags)
   -------------------------------------------------------------------------- */

.table-scroll { overflow-x: auto; margin: 24px 0; }

table {
  border-collapse: collapse;
  width: 100%;
  min-width: 620px;
  font: 400 0.92rem/1.5 var(--sans);
}

caption {
  text-align: left;
  font: 600 0.72rem var(--mono);
  color: var(--ink-3);
  padding-bottom: 10px;
}

th, td {
  border: 1px solid var(--rule);
  padding: 10px 14px;
  text-align: left;
  vertical-align: top;
  background: var(--paper-raised);
}

thead th {
  font: 700 0.78rem var(--mono);
  background: var(--paper);
  border-bottom: 2px solid var(--ink);
}

tbody th[scope="row"] { font: 600 0.8rem var(--mono); color: var(--ink-2); background: var(--paper); }

td .yes { color: var(--green-ink); font-family: var(--mono); font-weight: 700; }
td .no  { color: var(--ink-3); }

.flag { font-family: var(--mono); font-size: 0.8rem; white-space: nowrap; }

/* --------------------------------------------------------------------------
   Pricing tiers
   -------------------------------------------------------------------------- */

.tier-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 22px;
  margin: 36px 0 14px;
}

.tier {
  display: flex; flex-direction: column; gap: 12px;
  background: var(--paper-raised);
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  box-shadow: var(--shadow);
  padding: 26px 24px;
}
.tier-featured { border-color: var(--blue-ink); box-shadow: 4px 4px 0 rgba(34, 87, 201, 0.22); }

.tier h3 { margin: 0; font-size: 1rem; }
.tier .m-path { display: block; }
.price { font: 800 2.1rem/1 var(--mono); letter-spacing: -0.03em; }
.price small { font: 500 0.72rem var(--mono); color: var(--ink-3); letter-spacing: 0; }
.tier p { font-size: 0.92rem; color: var(--ink-2); margin: 0; }
.tier ul { margin: 0; padding-left: 18px; font-size: 0.9rem; color: var(--ink-2); display: grid; gap: 6px; }
.tier .btn { margin-top: auto; text-align: center; }

.badge-note {
  display: inline-block;
  font: 600 0.7rem var(--mono);
  color: var(--amber-ink);
  background: var(--amber-wash);
  border: 1px solid var(--amber-ink);
  border-radius: 3px;
  padding: 2px 8px;
}

/* --------------------------------------------------------------------------
   FAQ
   -------------------------------------------------------------------------- */

.faq { max-width: 760px; }
.faq details { border-bottom: 2px solid var(--rule-soft); }
.faq summary {
  font: 600 0.95rem var(--mono);
  padding: 18px 0;
  cursor: pointer;
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: '+ '; color: var(--blue-ink); font-weight: 700; }
.faq details[open] summary::before { content: '\2212 '; }
.faq details p { padding: 0 0 18px; color: var(--ink-2); max-width: 64ch; }

/* --------------------------------------------------------------------------
   Blog
   -------------------------------------------------------------------------- */

.post-item { padding: 30px 0; }
.post-item + .post-item { border-top: 2px solid var(--rule-soft); }
.post-item h3 { font-size: 1.1rem; margin-bottom: 8px; }
.post-item h3 a { color: var(--ink); text-decoration: none; }
.post-item h3 a:hover { color: var(--blue-ink); text-decoration: underline; }
.post-item p { color: var(--ink-2); font-size: 0.95rem; max-width: 64ch; margin-bottom: 10px; }

.chip {
  display: inline-block;
  font: 500 0.7rem var(--mono);
  color: var(--ink-2);
  background: var(--paper-raised);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: 2px 10px;
  margin-right: 6px;
}

/* --------------------------------------------------------------------------
   Article
   -------------------------------------------------------------------------- */

.article-head { padding: 64px 0 34px; }
.article-head .meta { font: 500 0.78rem var(--mono); color: var(--ink-3); margin-top: 14px; }

.article-body p { max-width: 68ch; }
.article-body h2 { font-size: 1.3rem; margin-top: 1.8em; }
.article-body ul { max-width: 66ch; color: var(--ink-2); }
.article-sec { padding-block: 8px 26px; }

/* --------------------------------------------------------------------------
   Forms
   -------------------------------------------------------------------------- */

.field { display: grid; gap: 7px; margin-bottom: 20px; }
.field label { font: 600 0.78rem var(--mono); color: var(--ink); }
.field .hint { font: italic 400 0.8rem var(--sans); color: var(--ink-3); }

input, select, textarea {
  width: 100%;
  font: 400 1rem var(--sans);
  color: var(--ink);
  background: var(--paper-raised);
  border: 1.5px solid var(--ink-2);
  border-radius: 4px;
  padding: 11px 12px;
}
textarea { min-height: 150px; resize: vertical; font-family: var(--mono); font-size: 0.9rem; }
input::placeholder, textarea::placeholder { color: var(--ink-3); }

.form-2col { display: grid; grid-template-columns: 1fr 1fr; gap: 0 18px; }

/* --------------------------------------------------------------------------
   404
   -------------------------------------------------------------------------- */

.err-wrap { padding: 90px 0 110px; }
.err-code {
  font: 800 clamp(4rem, 14vw, 8rem)/1 var(--mono);
  color: var(--ghost);
  letter-spacing: -0.05em;
  margin: 0 0 10px;
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */

.site-foot {
  border-top: 3px double var(--rule);
  margin-top: 48px;
  padding: 48px 0 60px;
}

.foot-grid {
  display: grid;
  grid-template-columns: 2.2fr 1fr 1fr 1fr;
  gap: 36px;
}

.foot-h { font: 700 0.78rem var(--mono); margin: 0 0 12px; color: var(--ink); }
.foot-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; font: 500 0.85rem var(--mono); }
.foot-list a { color: var(--ink-2); text-decoration: none; }
.foot-list a:hover { color: var(--blue-ink); text-decoration: underline; }

.foot-install {
  display: inline-block;
  margin-top: 14px;
  font: 500 0.78rem var(--mono);
  background: var(--paper-raised);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 9px 12px;
  color: var(--ink-2);
  white-space: nowrap;
  overflow-x: auto;
  max-width: 100%;
}
.foot-install .p { color: var(--blue-ink); font-weight: 700; }

.colophon {
  margin-top: 34px;
  padding-top: 18px;
  border-top: 1px solid var(--rule-soft);
  font: 400 0.75rem/1.7 var(--mono);
  color: var(--ink-3);
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 24px;
}

/* --------------------------------------------------------------------------
   Motion — every animation lives inside this query.
   Reduced-motion users get final states; .js gate keeps no-JS visible.
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }

  .caret { animation: caret-blink 1.06s steps(1) infinite; }
  @keyframes caret-blink { 50% { opacity: 0; } }

  a, .btn, .nav-links a { transition: color 140ms ease, background-color 140ms ease, border-color 140ms ease; }

  .js .reveal {
    opacity: 0;
    transform: translateY(12px);
    transition: opacity 480ms ease, transform 480ms ease;
  }
  .js .reveal.in { opacity: 1; transform: none; }

  .js .reveal-row {
    opacity: 0;
    transform: translateX(-14px);
    transition: opacity 420ms ease, transform 420ms ease;
  }
  .js .reveal-row.in { opacity: 1; transform: none; }
}

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */

@media (max-width: 980px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .foot-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 860px) {
  .nb { grid-template-columns: 1fr; }
  .nb-margin {
    text-align: left;
    border-right: 0;
    border-bottom: 3px double var(--rule);
    padding: 0 0 12px;
    margin-bottom: 22px;
  }
  .m-stick {
    position: static;
    display: flex; flex-wrap: wrap; align-items: baseline;
    justify-items: start; gap: 6px 18px;
  }
  .m-ln { font-size: 1.1rem; }
  .m-note { max-width: none; }
}

@media (max-width: 560px) {
  .sec { padding-block: 56px; }
  .hero { padding: 48px 0 64px; }
  .form-2col { grid-template-columns: 1fr; }
  .cta-band { padding: 28px 22px; }
  .foot-grid { grid-template-columns: 1fr; gap: 26px; }
  .term-body { font-size: 0.75rem; padding: 13px 14px; }
}