/* ==========================================================================
   SITE STYLES — drawing-set register
   Palette + type tokens locked per build brief §5.
   Night palette = typical dispatch charge window (21:00–06:00),
   applied as html.night by assets/js/site.js. Theme change transitions
   apply under prefers-reduced-motion too (theme, not motion).
   ========================================================================== */

/* ---------- fonts ----------
   PENDING: drop latin WOFF2 subsets into assets/fonts/ with these names.
   Until then, local() catches installed copies and the system stack serves. */
@font-face {
  font-family: 'IBM Plex Sans';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: local('IBM Plex Sans'), local('IBMPlexSans'),
       url('../fonts/plex-sans-400.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
       U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212,
       U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: 'IBM Plex Sans';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: local('IBM Plex Sans SemiBold'), local('IBMPlexSans-SemiBold'),
       url('../fonts/plex-sans-600.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
       U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212,
       U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: local('IBM Plex Mono'), local('IBMPlexMono'),
       url('../fonts/plex-mono-400.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
       U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212,
       U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: local('IBM Plex Mono Medium'), local('IBMPlexMono-Medium'),
       url('../fonts/plex-mono-500.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
       U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212,
       U+2215, U+FEFF, U+FFFD;
}

/* ---------- tokens ---------- */
:root {
  --paper: #FAFAF8;
  --ink: #1A1D21;
  --steel: #565B63;
  --copper: #9A5426;   /* 5.4:1 on paper — AA */
  --hairline: #E2E2DD;
  --copper-wash: rgba(154, 84, 38, 0.14);
  --sans: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI',
          Roboto, 'Helvetica Neue', Arial, sans-serif;
  --mono: 'IBM Plex Mono', ui-monospace, 'Cascadia Mono', 'SF Mono', Consolas,
          Menlo, monospace;
  --maxw: 1120px;
}
html.night {
  --paper: #15181C;
  --ink: #F3F2EE;
  --steel: #A9AEB6;    /* derived: night secondary, 7.8:1 on ground — AA */
  --copper: #C9784A;   /* 5.3:1 on ground — AA */
  --hairline: #2C3138;
  --copper-wash: rgba(201, 120, 74, 0.16);
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
* {
  transition: background-color .5s ease, color .5s ease,
              border-color .5s ease, fill .5s ease, stroke .5s ease;
}
html.boot * { transition: none !important; }

html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 1.125rem/1.7 var(--sans);
  font-synthesis-weight: none;
}
h1, h2, h3, p, figure, dl, dd { margin: 0; }
img, svg { display: block; max-width: 100%; height: auto; }
::selection { background: var(--copper); color: var(--paper); }

a { color: var(--copper); }
p a, dd a, .err a {
  color: var(--copper);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: background-color .5s ease, color .15s ease, border-color .15s ease;
}
:focus-visible { outline: 2px solid var(--copper); outline-offset: 3px; }

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--ink);
  color: var(--paper);
  font: 500 .75rem/1 var(--mono);
  letter-spacing: .12em;
  text-transform: uppercase;
  padding: .9em 1.2em;
  text-decoration: none;
  z-index: 10;
}
.skip:focus-visible { left: 0; }

.wrap {
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: clamp(20px, 4vw, 32px);
}

/* ---------- header / nav ---------- */
header { border-bottom: 1px solid var(--hairline); }
.nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  column-gap: clamp(1rem, 3vw, 2rem);
  row-gap: .35rem;
  padding-block: 16px;
}
.wordmark {
  font: 600 .9375rem/1 var(--sans);
  letter-spacing: .14em;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
}
.wordmark .wm2 { color: var(--steel); }
.nav nav { margin-left: auto; }
.nav-links {
  display: flex;
  gap: clamp(.9rem, 2.5vw, 1.75rem);
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  font: 500 .71875rem/1 var(--mono);
  letter-spacing: .14em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--steel);
  padding: .4em 0;
  transition: background-color .5s ease, color .15s ease, border-color .5s ease;
}
.nav-links a:hover { color: var(--copper); }
.nav-links a[aria-current="page"] {
  color: var(--ink);
  border-bottom: 1px solid var(--copper);
}

.chip {
  display: none;
  align-items: center;
  gap: .55em;
  font: 500 .65625rem/1 var(--mono);
  letter-spacing: .1em;
  color: var(--steel);
  border: 1px solid var(--hairline);
  padding: .6em .85em;
  white-space: nowrap;
}
.chip.on { display: inline-flex; }
.chip .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--copper);
  flex: none;
  animation: dotpulse 2.4s ease-in-out infinite;
}
.chip.state-standby .dot { background: var(--steel); animation: none; }
@keyframes dotpulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .25; }
}
@media (max-width: 759px) {
  .chip { order: 9; flex-basis: 100%; justify-content: center; margin-top: .5rem; }
}
@media (max-width: 420px) {
  .wordmark { font-size: .8125rem; letter-spacing: .12em; }
  .nav-links a { font-size: .625rem; letter-spacing: .11em; }
}

/* ---------- sections & rhythm ---------- */
section { padding-block: clamp(56px, 8vw, 120px); }
section + section { padding-top: 0; }

.divider {
  color: var(--steel);
  margin-bottom: clamp(40px, 6vw, 72px);
}

h1 {
  font: 600 clamp(2.4rem, 5vw, 4.2rem)/1.05 var(--sans);
  letter-spacing: -.015em;
  max-width: 22ch;
  margin-bottom: 1.6rem;
}
h2 {
  font: 600 clamp(1.5rem, 2.6vw, 2.0625rem)/1.2 var(--sans);
  letter-spacing: -.01em;
  max-width: 30ch;
  margin-bottom: 1.25rem;
}
.eyebrow {
  font: 500 .78125rem/1 var(--mono);
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--copper);
  margin-bottom: 1.5rem;
}
.subhead, .lede {
  font-size: clamp(1.125rem, 1.6vw, 1.3125rem);
  line-height: 1.6;
  color: var(--steel);
  max-width: 62ch;
}
.section-body { max-width: 65ch; }
.section-body p + p { margin-top: 1.2rem; }
.hero .section-body { margin-top: 2rem; }

/* ---------- hero ---------- */
.hero { padding-block: clamp(56px, 9vw, 128px) clamp(48px, 7vw, 96px); }
.hero-diagram { margin-top: clamp(48px, 7vw, 88px); }

/* ---------- diagram system ---------- */
.dgm .wire { stroke: var(--ink); stroke-width: 1.4; fill: none; }
.dgm .bus { stroke: var(--ink); stroke-width: 3; }
.dgm .conductor {
  stroke: var(--copper);
  stroke-width: 1.6;
  fill: none;
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  animation: energize 2s cubic-bezier(.6, .05, .3, 1) .5s forwards;
}
.dgm .sym { stroke: var(--ink); stroke-width: 1.4; fill: var(--paper); }
.dgm .blade { stroke: var(--ink); stroke-width: 1.4; fill: none; }
.dgm .node { fill: var(--ink); }
.dgm .node.hot { animation: nodehot .01s linear forwards; }
.dgm .node.d1 { animation-delay: .5s; }
.dgm .node.d2 { animation-delay: 1.48s; }
.dgm .node.d3 { animation-delay: 2.5s; }
.dgm .lbl {
  font: 500 11px/1 var(--mono);
  letter-spacing: .12em;
  fill: var(--steel);
}
.dgm .lbl-lg { font: 500 13px/1 var(--mono); letter-spacing: .12em; fill: var(--steel); }
.dgm .lbl-sm { font: 400 9px/1 var(--mono); letter-spacing: .08em; fill: var(--steel); }
@keyframes energize { to { stroke-dashoffset: 0; } }
@keyframes nodehot { to { fill: var(--copper); } }

.dgm-h { display: none; }
.dgm-v { display: block; max-width: 340px; margin-inline: auto; }
@media (min-width: 640px) {
  .dgm-h { display: block; }
  .dgm-v { display: none; }
}

/* ---------- doctrine ---------- */
.doctrine { display: grid; gap: 2.25rem; }
.doctrine > div { border-top: 1px solid var(--hairline); padding-top: 1.5rem; }
.doctrine h2 {
  font-size: 1.1875rem;
  line-height: 1.3;
  letter-spacing: 0;
  margin-bottom: .7rem;
}
.doctrine p { color: var(--steel); font-size: 1.03125rem; line-height: 1.65; }
@media (min-width: 760px) {
  .doctrine { grid-template-columns: repeat(3, 1fr); gap: 0; }
  .doctrine > div {
    border-top: 0;
    padding-top: 0;
    padding-inline: 2.25rem;
    border-left: 1px solid var(--hairline);
  }
  .doctrine > div:first-child { padding-left: 0; border-left: 0; }
  .doctrine > div:last-child { padding-right: 0; }
}

/* ---------- dispatch window ---------- */
.dispatch { margin: clamp(40px, 6vw, 64px) auto 0; max-width: 760px; }
.dispatch figcaption {
  font: 400 .71875rem/1.5 var(--mono);
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--steel);
  margin-top: 1.1rem;
  text-align: center;
}
.dw .axis { stroke: var(--ink); stroke-width: 1.2; }
.dw .tick { stroke: var(--steel); stroke-width: 1; }
.dw .tlabel {
  font: 400 15px var(--mono);
  letter-spacing: .06em;
  fill: var(--steel);
}
.dw .band-charge { fill: url(#hatch); stroke: var(--copper); stroke-width: 1; }
.dw .band-discharge {
  fill: var(--copper);
  fill-opacity: .16;
  stroke: var(--copper);
  stroke-width: 1;
}
.dw .hatchline { stroke: var(--copper); stroke-width: .9; opacity: .55; }
.dw .blabel {
  font: 500 14px var(--mono);
  letter-spacing: .16em;
  fill: var(--copper);
}

/* ---------- spec list (land) ---------- */
.spec { border-top: 1px solid var(--hairline); margin-top: 2.25rem; max-width: 65ch; }
.spec p {
  border-bottom: 1px solid var(--hairline);
  padding: 1rem 0;
  font-size: 1.0625rem;
  max-width: none;
}

/* ---------- approach blocks ---------- */
.blocks { display: grid; gap: 2.5rem; max-width: 65ch; }
.blocks > div { border-top: 1px solid var(--hairline); padding-top: 1.6rem; }
.blocks h2 { font-size: 1.375rem; margin-bottom: .8rem; }
.blocks p { color: var(--ink); }

/* ---------- CTA band ---------- */
.cta { border-block: 1px solid var(--hairline); display: grid; }
.cta > div { padding: clamp(2rem, 4vw, 3rem) 0; }
.cta > div + div { border-top: 1px solid var(--hairline); }
@media (min-width: 760px) {
  .cta { grid-template-columns: 1fr 1fr; }
  .cta > div { padding-inline: 0 2.5rem; }
  .cta > div + div {
    border-top: 0;
    border-left: 1px solid var(--hairline);
    padding-inline: 2.5rem 0;
  }
}
.cta .q {
  font: 500 .75rem/1 var(--mono);
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--steel);
  margin-bottom: 1rem;
}
.cta a {
  font: 600 clamp(1.25rem, 2vw, 1.5rem)/1.3 var(--sans);
  color: var(--copper);
  text-decoration: none;
}
.cta a:hover { text-decoration: underline; text-underline-offset: 4px; }
.cta .sep { color: var(--steel); font-size: clamp(1.25rem, 2vw, 1.5rem); }

/* ---------- contact block (company) ---------- */
.contact-block {
  border: 1px solid var(--hairline);
  padding: clamp(1.5rem, 3vw, 2.25rem);
  max-width: 560px;
  margin-top: 2.5rem;
}
.contact-block dt {
  font: 500 .65625rem/1 var(--mono);
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--steel);
  margin: 1.2rem 0 .3rem;
}
.contact-block dt:first-child { margin-top: 0; }
.contact-block dd { font: 400 .9375rem/1.6 var(--mono); color: var(--ink); }
.contact-block dd a { color: var(--ink); }
.contact-block dd a:hover { color: var(--copper); }

/* ---------- 404 ---------- */
.err { padding-block: clamp(72px, 12vw, 160px); }
.err .dgm { margin-top: clamp(40px, 6vw, 64px); max-width: 480px; }

/* ---------- footer title block ---------- */
footer { margin-top: clamp(48px, 7vw, 96px); }
.tblock {
  display: grid;
  gap: 1px;
  background: var(--hairline);
  border: 1px solid var(--hairline);
  margin-bottom: clamp(28px, 4vw, 48px);
}
@media (min-width: 860px) { .tblock { grid-template-columns: 2.1fr 1fr 1.4fr 1fr; } }
.tcell { background: var(--paper); padding: 1.15rem 1.3rem; }
.tcell, .tcell a {
  font: 400 .6875rem/1.8 var(--mono);
  letter-spacing: .1em;
  color: var(--steel);
}
.tcell a { text-decoration: none; display: inline-block; }
.tcell a:hover { color: var(--copper); }
.tcell .tk {
  display: block;
  font-weight: 500;
  letter-spacing: .16em;
  color: var(--ink);
  margin-bottom: .3rem;
  text-transform: uppercase;
}
.tcell .up { text-transform: uppercase; }
.tcell .wordmark { font-size: .8125rem; }
.tblock nav a { display: block; }

/