style.css

/* ===========================================================================
   Project Arete — projectarete.io
   One shared stylesheet for every page. No frameworks, no build step.
   ========================================================================== */

:root {
  --blue: #0f6feb;
  --blue-dark: #0a55b8;
  --blue-ink: #0b2e5e;
  --ink: #17222f;
  --body: #3d4a59;
  --muted: #6b7684;
  --bg: #ffffff;
  --panel: #f5f8fc;
  --border: #e3e9f1;
  --card-shadow: 0 1px 2px rgba(16, 35, 61, .04), 0 8px 24px rgba(16, 35, 61, .06);
  --radius: 14px;
  --maxw: 1080px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--body);
  background: var(--bg);
  line-height: 1.65;
  font-size: 17px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

h1, h2, h3, h4 { color: var(--ink); line-height: 1.25; letter-spacing: -.01em; }
h1 { font-size: 2.4rem; }
h2 { font-size: 1.6rem; }
h3 { font-size: 1.15rem; }
p { margin-bottom: 1.1rem; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
main { flex: 1; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

/* ---------------------------------------------------------------- header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.site-header .bar {
  max-width: var(--maxw); margin: 0 auto; padding: 14px 22px;
  display: flex; align-items: center; gap: 14px;
  position: relative;
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 700; font-size: 1.1rem; }
.brand img { width: 30px; height: 30px; border-radius: 7px; }
.brand:hover { text-decoration: none; }
.site-nav { margin-left: auto; }
.site-nav ul { list-style: none; display: flex; gap: 4px; }
.site-nav a {
  display: block; padding: 7px 12px; border-radius: 8px;
  color: var(--body); font-weight: 500; font-size: .95rem;
}
.site-nav a:hover { background: var(--panel); color: var(--ink); text-decoration: none; }
.site-nav a.active { color: var(--blue); font-weight: 650; }

.hamburger {
  display: none; margin-left: auto;
  width: 42px; height: 42px; border: 1px solid var(--border); border-radius: 9px;
  background: #fff; cursor: pointer;
  flex-direction: column; justify-content: center; align-items: center; gap: 5px;
}
.hamburger span { display: block; width: 20px; height: 2px; background: var(--ink); border-radius: 2px; }

/* ------------------------------------------------------------------ hero */
.hero {
  background:
    radial-gradient(1000px 420px at 85% -80px, rgba(15, 111, 235, .14), transparent 60%),
    radial-gradient(700px 380px at 0% 110%, rgba(15, 111, 235, .08), transparent 55%),
    var(--panel);
  border-bottom: 1px solid var(--border);
  padding: 72px 0 64px;
}
.hero .eyebrow {
  display: inline-block; font-size: .8rem; font-weight: 700; letter-spacing: .08em;
  text-transform: uppercase; color: var(--blue); margin-bottom: 14px;
}
.hero h1 { font-size: 2.9rem; max-width: 21ch; margin-bottom: 18px; }
.hero .lead { font-size: 1.2rem; color: var(--body); max-width: 62ch; margin-bottom: 8px; }
.hero .lede-note { color: var(--muted); font-size: 1rem; max-width: 62ch; }
.hero .cta-row { margin-top: 28px; display: flex; gap: 12px; flex-wrap: wrap; }

.btn {
  display: inline-block; padding: 11px 20px; border-radius: 10px;
  font-weight: 650; font-size: .98rem; border: 1px solid transparent;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--blue); color: #fff; }
.btn-primary:hover { background: var(--blue-dark); }
.btn-ghost { background: #fff; color: var(--blue-ink); border-color: var(--border); }
.btn-ghost:hover { border-color: var(--blue); color: var(--blue); }

/* ------------------------------------------------------------- page head */
.page-head { background: var(--panel); border-bottom: 1px solid var(--border); padding: 48px 0 40px; }
.page-head .eyebrow {
  display: inline-block; font-size: .8rem; font-weight: 700; letter-spacing: .08em;
  text-transform: uppercase; color: var(--blue); margin-bottom: 10px;
}
.page-head h1 { margin-bottom: 12px; }
.page-head p { max-width: 66ch; color: var(--body); margin-bottom: 0; }

/* -------------------------------------------------------------- sections */
.section { padding: 54px 0 10px; }
.section > .wrap > h2 { margin-bottom: 8px; }
.section .section-intro { color: var(--muted); max-width: 68ch; margin-bottom: 28px; }

/* ---- the four-step strip ---- */
.steps {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px;
  margin: 34px 0 6px;
}
.step {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 18px 14px; box-shadow: var(--card-shadow);
}
.steps.three { grid-template-columns: repeat(3, 1fr); }
.step .k {
  display: inline-block; font-size: .78rem; font-weight: 800; letter-spacing: .06em;
  text-transform: uppercase; color: var(--blue); margin-bottom: 6px;
}
.step p { font-size: .92rem; color: var(--body); margin: 0; }

/* ---- cards ---- */
.card {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--card-shadow); padding: 28px; margin-bottom: 22px;
}
.card h2 { margin-bottom: 12px; }
.card h3 { margin-bottom: 8px; }
.card :last-child { margin-bottom: 0; }

.card-split { display: grid; grid-template-columns: 5fr 7fr; gap: 28px; align-items: center; }
.card-split.flip { grid-template-columns: 7fr 5fr; }
.card-split .card-media img { width: 100%; height: auto; border-radius: 10px; border: 1px solid var(--border); }
.card-split.flip .card-media { order: 2; }

/* ---- grid of tiles (ecosystem / resources) ---- */
.tiles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-bottom: 22px; }
.tiles.two { grid-template-columns: repeat(2, 1fr); }
.tiles.four { grid-template-columns: repeat(4, 1fr); }
.tile {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--card-shadow); padding: 20px 20px 16px;
  display: flex; flex-direction: column;
}
.tile .t-icon { font-size: 1.5rem; margin-bottom: 8px; }
.tile h3 { margin-bottom: 6px; }
.tile p { font-size: .93rem; color: var(--body); margin-bottom: 10px; }
.tile .t-links { margin-top: auto; font-size: .92rem; font-weight: 600; }
.tile .t-links a { margin-right: 14px; white-space: nowrap; }

/* ---- definition list (concepts page) ---- */
.defs .card { scroll-margin-top: 90px; }
.defs .term-tag {
  display: inline-block; background: var(--panel); border: 1px solid var(--border);
  color: var(--blue-ink); font-size: .78rem; font-weight: 700;
  padding: 2px 10px; border-radius: 999px; margin-bottom: 10px;
  letter-spacing: .04em; text-transform: uppercase;
}

/* ---- callout ---- */
.callout {
  border-left: 4px solid var(--blue); background: var(--panel);
  border-radius: 0 10px 10px 0; padding: 16px 20px; margin-bottom: 22px;
  font-size: .95rem;
}
.callout.warn { border-left-color: #d99114; }
.callout :last-child { margin-bottom: 0; }

/* ---- prose lists ---- */
.card ul, .prose ul { margin: 0 0 1.1rem 1.4rem; }
.card li, .prose li { margin-bottom: .45rem; }

.mono { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: .92em; background: var(--panel); border: 1px solid var(--border); border-radius: 6px; padding: 1px 6px; }

/* ---- code block (gateway page) ---- */
.code-block {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .88rem; line-height: 1.6; color: var(--blue-ink);
  background: var(--panel); border: 1px solid var(--border); border-radius: 10px;
  padding: 16px 18px; overflow-x: auto; margin-bottom: 1.1rem;
  white-space: pre;
}
.code-block .c { color: var(--muted); }

/* ---- copyable URL card (ARETE.md page) ---- */
.url-card { border-color: #cfe0f8; background: linear-gradient(180deg, #fbfdff, #fff); }
.url-card h3 { margin-bottom: 12px; }
.url-row { display: flex; gap: 10px; align-items: stretch; flex-wrap: wrap; margin-bottom: 10px; }
.url-box {
  flex: 1 1 380px; min-width: 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .92rem; color: var(--blue-ink);
  background: var(--panel); border: 1px solid var(--border); border-radius: 10px;
  padding: 12px 14px; overflow-wrap: anywhere; user-select: all;
}
.copy-btn { cursor: pointer; font-family: inherit; flex: 0 0 auto; }
.copy-btn.copied { border-color: var(--blue); color: var(--blue); }

/* ---- inline copy icon (sits directly after a .mono command) ---- */
.copy-inline {
  display: inline-flex; align-items: center; justify-content: center;
  vertical-align: baseline; margin-left: 5px; padding: 3px;
  width: 24px; height: 24px;
  background: transparent; border: 1px solid transparent; border-radius: 6px;
  color: var(--muted); cursor: pointer;
  transition: color .15s ease, background-color .15s ease, border-color .15s ease;
}
.copy-inline svg { width: 14px; height: 14px; display: block; }
.copy-inline .icon-check { display: none; }
.copy-inline:hover { color: var(--blue); background: #fff; border-color: var(--border); }
.copy-inline:focus-visible { outline: 2px solid var(--blue); outline-offset: 1px; }
.copy-inline.copied { color: var(--blue); border-color: var(--blue); background: #fff; }
.copy-inline.copied .icon-copy { display: none; }
.copy-inline.copied .icon-check { display: block; }
@media (prefers-reduced-motion: reduce) { .copy-inline { transition: none; } }
.url-note { color: var(--muted); font-size: .92rem; margin-bottom: 18px; }

/* ---- big CTA band ---- */
.cta-band {
  margin: 44px 0 64px; padding: 40px;
  background: linear-gradient(120deg, var(--blue-ink), var(--blue-dark));
  border-radius: 18px; color: #fff;
}
.cta-band h2 { color: #fff; margin-bottom: 10px; }
.cta-band p { color: rgba(255, 255, 255, .85); max-width: 64ch; }
.cta-band .cta-row { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 18px; }
.cta-band .btn-ghost { background: transparent; color: #fff; border-color: rgba(255, 255, 255, .45); }
.cta-band .btn-ghost:hover { border-color: #fff; color: #fff; }
.cta-band .btn-primary { background: #fff; color: var(--blue-ink); }
.cta-band .btn-primary:hover { background: #eaf1fd; }

/* ---------------------------------------------------------------- footer */
.site-footer { background: #0e1726; color: #aab6c6; margin-top: 40px; }
.site-footer .cols {
  max-width: var(--maxw); margin: 0 auto; padding: 44px 22px 20px;
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 28px;
}
.site-footer h4 { color: #fff; font-size: .95rem; margin-bottom: 12px; }
.site-footer ul { list-style: none; }
.site-footer li { margin-bottom: 8px; font-size: .92rem; }
.site-footer a { color: #aab6c6; }
.site-footer a:hover { color: #fff; }
.site-footer .about { font-size: .92rem; max-width: 34ch; }
.site-footer .about .f-brand { color: #fff; font-weight: 700; margin-bottom: 10px; display: flex; align-items: center; gap: 8px; }
.site-footer .about .f-brand img { width: 24px; height: 24px; border-radius: 6px; }
.site-footer .tail {
  border-top: 1px solid rgba(255, 255, 255, .09);
  max-width: var(--maxw); margin: 0 auto; padding: 16px 22px 22px;
  font-size: .85rem; color: #7f8b9b;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
}

/* ---------------------------------------------------- nav groups (v2 nav) */
.site-nav .has-sub { position: relative; }
.site-nav .nav-group {
  display: flex; align-items: center; gap: 5px;
  padding: 7px 12px; border-radius: 8px;
  border: none; background: none; cursor: pointer;
  color: var(--body); font-weight: 500; font-size: .95rem;
  font-family: inherit; line-height: inherit;
}
.site-nav .nav-group:hover { background: var(--panel); color: var(--ink); }
.site-nav .nav-group.active { color: var(--blue); font-weight: 650; }
.site-nav .caret { font-size: .68em; line-height: 1; transition: transform .15s ease; }
.site-nav .sub {
  display: none; position: absolute; top: 100%; left: 0; z-index: 60;
  min-width: 190px; list-style: none; margin: 0; padding: 6px;
  background: #fff; border: 1px solid var(--border); border-radius: 10px;
  box-shadow: var(--card-shadow);
}
.site-nav .has-sub:hover > .sub,
.site-nav .has-sub:focus-within > .sub,
.site-nav .has-sub.open > .sub { display: block; }
.site-nav .has-sub:hover > .nav-group .caret,
.site-nav .has-sub.open > .nav-group .caret { transform: rotate(180deg); }
.site-nav .sub a { padding: 8px 12px; white-space: nowrap; }
@media (prefers-reduced-motion: reduce) { .site-nav .caret { transition: none; } }

/* ------------------------------------------------------------ responsive */
@media (max-width: 860px) {
  .hamburger { display: flex; }
  .site-nav {
    display: none;
    position: absolute; left: 0; right: 0; top: 100%;
    background: #fff; border-bottom: 1px solid var(--border);
    box-shadow: 0 14px 30px rgba(16, 35, 61, .12);
  }
  .site-nav.open { display: block; }
  .site-nav ul { flex-direction: column; padding: 10px 16px 14px; gap: 2px; }
  .site-nav a { padding: 11px 12px; font-size: 1rem; }

  /* groups flatten: label becomes a section heading, subs always visible */
  .site-nav .has-sub { position: static; }
  .site-nav .nav-group {
    width: 100%; cursor: default;
    color: var(--muted); font-size: .8rem; font-weight: 700;
    text-transform: uppercase; letter-spacing: .06em;
    padding: 12px 12px 2px;
  }
  .site-nav .nav-group:hover { background: none; color: var(--muted); }
  .site-nav .caret { display: none; }
  .site-nav .sub,
  .site-nav .has-sub > .sub {
    display: block; position: static;
    border: none; box-shadow: none; border-radius: 0;
    padding: 0 0 2px 8px; min-width: 0;
  }
}

@media (max-width: 900px) {
  .steps, .steps.three { grid-template-columns: repeat(2, 1fr); }
  .tiles, .tiles.four { grid-template-columns: repeat(2, 1fr); }
  .card-split, .card-split.flip { grid-template-columns: 1fr; }
  .card-split.flip .card-media { order: 0; }
  .site-footer .cols { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .hero { padding: 48px 0 44px; }
  .hero h1 { font-size: 2.1rem; }
  h1 { font-size: 1.9rem; }
  .steps, .steps.three { grid-template-columns: 1fr; }
  .tiles, .tiles.two, .tiles.four { grid-template-columns: 1fr; }
  .cta-band { padding: 28px 22px; }

  .site-footer .cols { grid-template-columns: 1fr; }
}