/* weather-skills.org — technical data-sheet aesthetic.
   Plain CSS, system fonts only, zero third-party requests. */

:root {
  --paper: #f7f4ec;
  --paper-deep: #efeadd;
  --ink: #1d211f;
  --ink-soft: #4c544f;
  --rule: #c9c2b0;
  --rule-faint: #ddd7c7;
  --accent: #11606a;
  --accent-deep: #0b454d;
  --warn-bg: #f4e9d3;
  --warn-edge: #b07d2e;
  --code-bg: #20262a;
  --code-ink: #d8e0d9;
  --serif: "Charter", "Iowan Old Style", "Palatino", "Georgia", serif;
  --mono: ui-monospace, "SF Mono", "Menlo", "Consolas", monospace;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--serif);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink);
  background-color: var(--paper);
  /* faint graph-paper grid */
  background-image:
    linear-gradient(var(--rule-faint) 1px, transparent 1px),
    linear-gradient(90deg, var(--rule-faint) 1px, transparent 1px);
  background-size: 36px 36px;
}

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--accent-deep); }

code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--paper-deep);
  border: 1px solid var(--rule-faint);
  border-radius: 2px;
  padding: 0.05em 0.3em;
  overflow-wrap: anywhere;
}

pre {
  background: var(--code-bg);
  color: var(--code-ink);
  border-radius: 3px;
  border-left: 3px solid var(--accent);
  padding: 0.9rem 1.1rem;
  overflow-x: auto;
  font-size: 0.8125rem;
  line-height: 1.55;
}

pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: inherit;
  white-space: pre;
}

/* ---------- masthead ---------- */

.masthead {
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.02em;
}

.masthead-inner {
  max-width: 62rem;
  margin: 0 auto;
  padding: 0.6rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  flex-wrap: wrap;
}

.masthead-meta { color: var(--ink-soft); }
.masthead-meta a { color: var(--ink-soft); }

.site-id { font-weight: 700; color: var(--ink); }

.meta-sep { margin: 0 0.4em; color: var(--rule); }

.masthead-nav a {
  color: var(--ink);
  text-decoration: none;
  margin-left: 1.1rem;
  border-bottom: 1px solid transparent;
}
.masthead-nav a:first-child { margin-left: 0; }
.masthead-nav a:hover { border-bottom-color: var(--accent); color: var(--accent-deep); }

/* ---------- hero ---------- */

.hero {
  border-bottom: 1px solid var(--rule);
  background:
    linear-gradient(180deg, rgba(17, 96, 106, 0.06), rgba(17, 96, 106, 0) 55%),
    var(--paper);
}

.hero-inner {
  max-width: 62rem;
  margin: 0 auto;
  padding: 3.5rem 1.25rem 2.75rem;
}

.kicker {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--accent);
  margin: 0 0 1rem;
}

.hero h1 {
  font-size: clamp(1.9rem, 4.5vw, 3.1rem);
  line-height: 1.12;
  letter-spacing: -0.015em;
  margin: 0 0 1.1rem;
  max-width: 24ch;
}

.lede {
  font-size: 1.15rem;
  max-width: 56ch;
  color: var(--ink-soft);
  margin: 0 0 1.75rem;
}

.hero-cmd { max-width: 46rem; }

.cmd-label {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
  margin: 0 0 0.35rem;
}

.notice {
  margin-top: 1.75rem;
  max-width: 46rem;
  background: var(--warn-bg);
  border-left: 3px solid var(--warn-edge);
  padding: 0.65rem 1rem;
  font-size: 0.9rem;
}

/* ---------- sections ---------- */

.section {
  max-width: 62rem;
  margin: 0 auto;
  padding: 2.75rem 1.25rem 1.5rem;
  border-bottom: 1px solid var(--rule-faint);
}

.section > p { max-width: 62ch; }

.section-head {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  border-bottom: 2px solid var(--ink);
  padding-bottom: 0.4rem;
  margin-bottom: 1.4rem;
}

.section-no {
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 700;
}

.section-head h2 {
  font-size: 1.55rem;
  margin: 0;
  letter-spacing: -0.01em;
}

/* ---------- pipeline flow ---------- */

.flow {
  list-style: none;
  display: flex;
  align-items: stretch;
  gap: 2rem;
  margin: 1.75rem 0;
  padding: 0;
  flex-wrap: wrap;
}

.flow-stage {
  position: relative;
  flex: 1 1 12rem;
  border: 1px solid var(--rule);
  background: var(--paper-deep);
  padding: 0.9rem 1rem;
  border-radius: 3px;
}

.flow-stage:not(:last-child)::after {
  content: "\2192";
  content: "\2192" / "";
  position: absolute;
  right: -1.7rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.4rem;
  color: var(--accent);
}

.flow-stage h3 {
  font-family: var(--mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent-deep);
  margin: 0 0 0.2rem;
}

.flow-stage p {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--ink-soft);
  margin: 0 0 0.6rem;
}

.flow-stage ul {
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--mono);
  font-size: 0.78rem;
}

.flow-stage li { padding: 0.12rem 0; border-top: 1px dotted var(--rule); }

.example-label {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
  margin: 1.5rem 0 0.35rem;
}

/* ---------- envelope schemas ---------- */

.schema-pair {
  display: flex;
  gap: 1rem;
  margin: 1.5rem 0;
  flex-wrap: wrap;
}

.schema {
  flex: 1 1 16rem;
  border: 1px solid var(--rule);
  border-radius: 3px;
  background: var(--paper-deep);
  padding: 0.9rem 1rem;
}

.schema h3 {
  font-size: 1rem;
  margin: 0 0 0.5rem;
}

.schema pre {
  border-left-width: 2px;
  font-size: 0.78rem;
  margin: 0 0 0.5rem;
}

.schema p {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--ink-soft);
  margin: 0;
}

/* ---------- skill catalog ---------- */

.group-head {
  font-size: 1.1rem;
  margin: 2rem 0 0.6rem;
  letter-spacing: -0.005em;
}

.group-note {
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  margin-left: 0.6rem;
}

.catalog {
  margin: 0;
  border-top: 1px solid var(--rule);
}

.skill {
  display: grid;
  grid-template-columns: 11.5rem 1fr;
  gap: 1.25rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--rule-faint);
}

.skill dt {
  font-family: var(--mono);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--accent-deep);
  padding-top: 0.15rem;
  overflow-wrap: anywhere;
}

.skill dd {
  margin: 0;
  font-size: 0.95rem;
  color: var(--ink-soft);
}

.skill dd strong { color: var(--ink); }

/* ---------- install ---------- */

.install-path {
  border-left: 2px solid var(--rule);
  padding-left: 1.25rem;
  margin: 1.75rem 0;
}

.install-path h3 { margin: 0 0 0.4rem; font-size: 1.1rem; }
.install-path p { max-width: 62ch; margin: 0.4rem 0; }
.install-path pre { max-width: 46rem; }

/* ---------- governance ---------- */

.teaser {
  font-style: italic;
  color: var(--ink-soft);
}

.cta {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.85rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--paper);
  background: var(--accent);
  border-radius: 2px;
  padding: 0.55rem 1rem;
}

.cta:hover { background: var(--accent-deep); color: var(--paper); }

/* ---------- footer ---------- */

.footer {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--ink-soft);
}

.footer a { color: var(--ink-soft); }

.footer-inner {
  max-width: 62rem;
  margin: 0 auto;
  padding: 1.25rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ---------- narrow screens ---------- */

/* The three flow stages (flex-basis 12rem each, two 2rem gaps) need a 40rem
   (640px) row; with the section's 1.25rem side padding that row no longer
   fits below a 680px viewport. Switch the flow to its column layout at that
   point so the stages never wrap while horizontal arrows are drawn. */
@media (max-width: 680px) {
  .flow { flex-direction: column; gap: 2.2rem; }
  .flow-stage:not(:last-child)::after {
    content: "\2193";
    content: "\2193" / "";
    right: auto;
    left: 50%;
    top: auto;
    bottom: -1.9rem;
    transform: translateX(-50%);
  }
}

@media (max-width: 640px) {
  body { font-size: 1rem; }

  .masthead-inner { flex-direction: column; gap: 0.35rem; }
  .masthead-nav a { margin-left: 0; margin-right: 1rem; }

  .hero-inner { padding-top: 2.25rem; }

  .skill {
    grid-template-columns: 1fr;
    gap: 0.15rem;
  }

  .install-path { padding-left: 0.9rem; }
}