/* Pulse (pulse.cliq.im) - one stylesheet for every page.
   Layout: a radio operator's field notes. One left-aligned reading column (~68ch) with signal readouts set in
   mono; a wider band for diagrams and the self-check. The one bold element is the signal pulse in the hero.
   Palette: cool slate paper, deep slate ink, signal amber for the signal, a radio teal for links. */
:root {
  --bg: #f4f7f8;          /* page: off-white with a cool slate bias */
  --surface: #ffffff;     /* cards, packet readouts */
  --ink: #15222b;         /* text */
  --muted: #536470;       /* secondary text */
  --line: #d3dce1;        /* hairlines */
  --signal: #f0a500;      /* the signal: marks, pulses, fills */
  --signal-ink: #8a5400;  /* amber that passes contrast as text on light */
  --link: #0a6680;        /* links */
  --ok: #2f7d4a;
  --warn: #a8571a;
  --tint: #fbf3e2;        /* faint amber wash for callouts */
  --on-signal: #1c1300;   /* text on an amber fill (amber in both themes) */
  --font-display: "IBM Plex Sans Condensed", "Arial Narrow", "Roboto Condensed", sans-serif;
  --font-body: "IBM Plex Sans", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --step--1: 0.875rem;
  --step-0: 1.0625rem;
  --step-1: 1.3rem;
  --step-2: 1.7rem;
  --step-3: 2.3rem;
  --step-4: clamp(2.8rem, 8vw, 5.2rem);
  --measure: 68ch;
  --wide: 72rem;
  --radius: 6px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0d1418; --surface: #141f25; --ink: #e5ecef; --muted: #9badb7; --line: #26363f;
    --signal: #f5b83d; --signal-ink: #f5b83d; --link: #62c4dd; --ok: #6cc28a; --warn: #f0a26a; --tint: #1f2a22;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0d1418; --surface: #141f25; --ink: #e5ecef; --muted: #9badb7; --line: #26363f;
  --signal: #f5b83d; --signal-ink: #f5b83d; --link: #62c4dd; --ok: #6cc28a; --warn: #f0a26a; --tint: #1f2a22;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 400 var(--step-0)/1.6 var(--font-body);
  text-rendering: optimizeLegibility;
}
img, svg { max-width: 100%; height: auto; }
a { color: var(--link); text-underline-offset: 0.18em; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--signal); outline-offset: 2px; border-radius: 2px; }
h1, h2, h3 { font-family: var(--font-display); font-weight: 600; line-height: 1.15; text-wrap: balance; margin: 0; }
h1 { font-size: var(--step-3); letter-spacing: -0.01em; }
h2 { font-size: var(--step-2); }
h3 { font-size: var(--step-1); }
p, ul, ol { margin: 0; }
ul, ol { padding-left: 1.25em; }
li + li { margin-top: 0.35em; }
code, .mono { font-family: var(--font-mono); font-size: 0.92em; }
.skip { position: absolute; left: -999px; top: 0; }
.skip:focus { left: max(16px, env(safe-area-inset-left, 0px)); top: 8px; background: var(--surface); padding: 6px 10px; z-index: 20; }

/* animated node-chain background (assets/mesh-bg.js): behind everything, never in the way */
.mesh-bg { position: fixed; inset: 0; z-index: 0; pointer-events: none; }
.site-head, main, .site-foot, body > .wrap { position: relative; z-index: 1; }

/* gutters: one place */
.wrap {
  max-width: var(--wide); margin: 0 auto;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
}

/* header */
.site-head { border-bottom: 1px solid var(--line); background: var(--bg); }
.site-head .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 10px 24px; padding-block: 14px; }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.brand svg { width: 28px; height: 28px; flex: none; }
.brand b { font: 700 1.25rem/1 var(--font-display); letter-spacing: 0.14em; }
.brand small { display: block; font: 400 0.72rem/1.2 var(--font-mono); color: var(--muted); letter-spacing: 0.02em; }
.nav ul { list-style: none; padding: 0; display: flex; flex-wrap: wrap; gap: 4px 18px; }
.nav li + li { margin: 0; }
.nav a { color: var(--ink); text-decoration: none; font-size: var(--step--1); font-weight: 500; padding-block: 4px; border-bottom: 2px solid transparent; }
.nav a:hover { border-bottom-color: var(--line); }
.nav a[aria-current="page"] { border-bottom-color: var(--signal); }
.nav .primary { color: var(--signal-ink); font-weight: 600; }

/* page body */
main { padding-block: 40px 64px; }
.col { max-width: var(--measure); display: grid; gap: 1.1rem; }
.col > h2 { margin-top: 1.6rem; }
.col > h3 { margin-top: 0.6rem; }
.lede { font-size: var(--step-1); line-height: 1.5; color: var(--ink); }
.eyebrow { font: 500 0.78rem/1.2 var(--font-mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--signal-ink); }
.muted { color: var(--muted); }
.page-head { display: grid; gap: 0.7rem; max-width: var(--measure); margin-bottom: 1.6rem; }

/* readout: the subject's own detail - signal reports in mono */
.readout {
  font: 400 var(--step--1)/1.5 var(--font-mono); color: var(--muted);
  display: flex; flex-wrap: wrap; gap: 4px 18px;
}
.readout span::before { content: "\25CF"; color: var(--signal); margin-right: 6px; font-size: 0.7em; vertical-align: 0.15em; }

/* packet card: what goes out on air */
.packet {
  background: var(--surface); border: 1px solid var(--line); border-left: 4px solid var(--signal);
  border-radius: var(--radius); padding: 14px 16px; display: grid; gap: 8px; max-width: 40rem;
}
.packet .msg { font: 400 1rem/1.5 var(--font-mono); color: var(--ink); overflow-wrap: anywhere; }
.packet .meta { font: 400 0.78rem/1.4 var(--font-mono); color: var(--muted); display: flex; flex-wrap: wrap; gap: 4px 16px; }

/* callouts */
.note { background: var(--tint); border-radius: var(--radius); padding: 14px 16px; display: grid; gap: 6px; }
.note strong { font-family: var(--font-display); font-size: 1.05rem; }
.draft { border: 1px dashed var(--warn); color: var(--warn); border-radius: var(--radius); padding: 2px 6px; font: 500 0.8rem/1.5 var(--font-mono); }
.status {
  display: grid; gap: 6px; border: 1px solid var(--line); background: var(--surface); border-radius: var(--radius); padding: 14px 16px;
}
.status .pill { justify-self: start; font: 600 0.78rem/1 var(--font-mono); letter-spacing: 0.06em; text-transform: uppercase;
  padding: 6px 8px; border-radius: 4px; background: var(--tint); color: var(--signal-ink); }

/* hero */
.hero { display: grid; gap: 28px; align-items: center; padding-block: 8px 24px; }
@media (min-width: 860px) { .hero { grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); } }
.hero h1 { font: 700 var(--step-4)/0.95 var(--font-display); letter-spacing: 0.12em; }
.hero .tag { font: 600 var(--step-2)/1.2 var(--font-display); }
.hero .core { font-size: var(--step-1); color: var(--muted); max-width: 34ch; }
.hero-text { display: grid; gap: 16px; min-width: 0; }
.pulse { position: relative; aspect-ratio: 1; width: min(100%, 360px); justify-self: center; }
.pulse svg { width: 100%; height: 100%; display: block; }
.pulse .ring { fill: none; stroke: var(--signal); stroke-width: 1.5; transform-origin: 50% 50%; opacity: 0.55; }
.pulse .ring.r2 { opacity: 0.35; } .pulse .ring.r3 { opacity: 0.2; }
.pulse .node { fill: var(--surface); stroke: var(--muted); stroke-width: 1.5; }
.pulse .link { stroke: var(--line); stroke-width: 1.5; stroke-dasharray: 3 5; }
.pulse .core-dot { fill: var(--signal); }
@media (prefers-reduced-motion: no-preference) {
  .pulse .ring { animation: ping 4.8s ease-out infinite; }
  .pulse .ring.r2 { animation-delay: 1.6s; } .pulse .ring.r3 { animation-delay: 3.2s; }
  @keyframes ping { 0% { transform: scale(0.35); opacity: 0.6; } 80% { opacity: 0.08; } 100% { transform: scale(1); opacity: 0; } }
}

.cta-row { display: flex; flex-wrap: wrap; gap: 10px 14px; align-items: center; }
.btn {
  display: inline-flex; align-items: center; gap: 8px; text-decoration: none; font-weight: 600;
  padding: 11px 16px; border-radius: var(--radius); border: 1px solid var(--line); color: var(--ink); background: var(--surface);
}
.btn.primary { background: var(--signal); border-color: var(--signal); color: var(--on-signal); }
.btn:hover { border-color: var(--ink); }
.btn.primary:hover { filter: brightness(1.05); border-color: var(--signal); }

/* sections on the home page */
.band { padding-block: 34px; border-top: 1px solid var(--line); }
.band h2 { margin-bottom: 18px; }
.three { display: grid; gap: 22px; }
@media (min-width: 760px) { .three { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
.three article { display: grid; gap: 8px; align-content: start; min-width: 0; }
.three .mono { color: var(--signal-ink); font-size: 0.8rem; letter-spacing: 0.06em; text-transform: uppercase; }
.split { display: grid; gap: 22px; align-items: start; }
@media (min-width: 860px) { .split { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); } }
.split > * { min-width: 0; }

/* table of contents on long pages */
.toc { border-left: 2px solid var(--line); padding-left: 14px; font-size: var(--step--1); }
.toc ol { padding-left: 1.1em; }

/* diagrams */
figure { margin: 0; display: grid; gap: 8px; }
figure .scroll { overflow-x: auto; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px; }
figure svg text { fill: var(--ink); font-family: var(--font-mono); font-size: 13px; }
figure svg .dim { fill: var(--muted); }
figure svg .stroke { stroke: var(--muted); fill: none; stroke-width: 1.5; }
figure svg .hot { stroke: var(--signal); fill: none; stroke-width: 3; }
figure svg .n { fill: var(--surface); stroke: var(--ink); stroke-width: 1.5; }
figure svg .nb { fill: var(--signal); stroke: var(--signal); }
figure svg .ground { fill: var(--line); }
figure svg .bar { fill: var(--line); }
figure svg .barfill { fill: var(--signal); }
figure svg .warnline { stroke: var(--warn); stroke-width: 2; stroke-dasharray: 5 4; }
figcaption { font-size: var(--step--1); color: var(--muted); }

/* self-check */
.check { display: grid; gap: 18px; max-width: 46rem; }
.check fieldset { border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); padding: 14px 16px 16px; margin: 0; display: grid; gap: 8px; min-width: 0; }
.check legend { font: 600 1.08rem/1.3 var(--font-display); padding: 0 6px; }
.check .opts { display: grid; gap: 6px; }
@media (min-width: 620px) { .check .opts { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
.check label { display: flex; gap: 10px; align-items: flex-start; padding: 8px 10px; border: 1px solid var(--line); border-radius: 5px; cursor: pointer; }
.check label:has(input:checked) { border-color: var(--signal); background: var(--tint); }
.check input { margin-top: 0.3em; accent-color: var(--signal); }
.check .hint { font-size: var(--step--1); color: var(--muted); }
.results { display: grid; gap: 14px; max-width: 46rem; }
.rec { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; display: grid; gap: 6px; }
.rec h3 { font-size: 1.12rem; }
.rec .why { color: var(--muted); font-size: var(--step--1); }
.rec .tag { font: 500 0.74rem/1 var(--font-mono); letter-spacing: 0.06em; text-transform: uppercase; color: var(--signal-ink); }
.rec.good { border-left: 4px solid var(--ok); } .rec.do { border-left: 4px solid var(--signal); }
details { border-top: 1px solid var(--line); padding-block: 10px; }
details summary { cursor: pointer; font-weight: 600; }
details > div { display: grid; gap: 8px; padding-top: 8px; }

/* contact form */
form.contact { display: grid; gap: 12px; max-width: 34rem; }
form.contact label { display: grid; gap: 4px; font-weight: 500; }
form.contact input, form.contact textarea {
  font: inherit; color: var(--ink); background: var(--surface); border: 1px solid var(--line); border-radius: 5px; padding: 9px 10px; width: 100%;
}
form.contact textarea { min-height: 8rem; resize: vertical; }
form.contact .hp { position: absolute; left: -5000px; width: 1px; height: 1px; overflow: hidden; }
form.contact button { justify-self: start; font: inherit; font-weight: 600; cursor: pointer; padding: 10px 16px; border-radius: var(--radius);
  border: 1px solid var(--signal); background: var(--signal); color: var(--on-signal); }
form.contact button[disabled] { opacity: 0.55; cursor: not-allowed; }
.form-msg { font-size: var(--step--1); }

/* resource list */
.res { list-style: none; padding: 0; display: grid; gap: 14px; }
.res li { display: grid; gap: 3px; }
.res li + li { margin: 0; }
.res .src { font: 400 0.78rem/1.4 var(--font-mono); color: var(--muted); }

/* footer */
.site-foot { border-top: 1px solid var(--line); padding-block: 26px 36px; font-size: var(--step--1); color: var(--muted); }
.site-foot .wrap { display: grid; gap: 10px; }
.site-foot ul { list-style: none; padding: 0; display: flex; flex-wrap: wrap; gap: 4px 16px; }
.site-foot li + li { margin: 0; }
.site-foot a { color: var(--muted); }