/* ---------- tokens ---------- */
:root {
  --bg: #0d1117;
  --bg-alt: #11161f;
  --surface: #161d29;
  --border: #26303f;
  --text: #dbe2ec;
  --text-dim: #93a0b4;
  --accent: #4fd1a5;
  --accent-strong: #2fb98a;
  --accent-ink: #06221a;
  --max: 1080px;
  color-scheme: dark;
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #fafaf8; --bg-alt: #f1f2ef; --surface: #ffffff; --border: #dfe3da;
    --text: #1c2430; --text-dim: #5b6674;
    --accent: #0e8a63; --accent-strong: #0a6f50; --accent-ink: #ffffff;
    color-scheme: light;
  }
}
:root[data-theme="light"] {
  --bg: #fafaf8; --bg-alt: #f1f2ef; --surface: #ffffff; --border: #dfe3da;
  --text: #1c2430; --text-dim: #5b6674;
  --accent: #0e8a63; --accent-strong: #0a6f50; --accent-ink: #ffffff;
  color-scheme: light;
}

/* ---------- base ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}
.container { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
h1, h2, h3 { line-height: 1.2; margin: 0 0 .5em; }
p { margin: 0 0 1em; }
a { color: var(--accent); }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; height: 60px; }
.brand { font-weight: 700; font-size: 1.05rem; color: var(--text); text-decoration: none; letter-spacing: .01em; }
.brand-dot { color: var(--accent); }
.site-nav { display: flex; gap: 18px; align-items: center; margin-left: auto; }
.site-nav a { color: var(--text-dim); text-decoration: none; font-size: .92rem; }
.site-nav a:hover { color: var(--text); }
.site-nav .lang, .site-nav .theme-toggle {
  border: 1px solid var(--border); border-radius: 999px;
  padding: 3px 12px; font-weight: 600; color: var(--accent);
  background: none; font: inherit; font-size: .92rem; cursor: pointer; line-height: 1.5;
}
.site-nav .lang:hover, .site-nav .theme-toggle:hover { border-color: var(--accent); }
.site-nav .nav-cta {
  background: var(--accent); color: var(--accent-ink);
  border-radius: 999px; padding: 5px 14px; font-weight: 700;
}
.site-nav .nav-cta:hover { background: var(--accent-strong); color: var(--accent-ink); }
.nav-burger {
  display: none; width: 38px; height: 34px; padding: 0;
  place-items: center; border: 1px solid var(--border); border-radius: 10px;
  background: var(--surface); color: var(--text);
  font: inherit; font-size: 1.05rem; line-height: 1; cursor: pointer; margin-left: 10px;
}
.nav-burger:hover { border-color: var(--accent); }

/* ---------- hero ---------- */
.hero { padding: 84px 0 60px; position: relative; overflow: hidden; }
.hero::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background:
    radial-gradient(600px 300px at 85% 10%, color-mix(in srgb, var(--accent) 14%, transparent), transparent 70%),
    radial-gradient(500px 260px at 8% 90%, color-mix(in srgb, var(--accent) 8%, transparent), transparent 70%);
}
.hero .container { position: relative; }
.kicker {
  color: var(--accent); font-weight: 600; letter-spacing: .14em;
  text-transform: uppercase; font-size: .78rem; margin-bottom: 14px;
}
.kicker .rotator { border-right: 2px solid var(--accent); padding-right: 2px; }
.hero h1 { font-size: clamp(2rem, 5.2vw, 3.3rem); letter-spacing: -.02em; }
.lede { color: var(--text-dim); font-size: 1.1rem; max-width: 46rem; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin: 24px 0 0; }
.hero-cta .cta { margin-top: 0; font-size: .98rem; padding: 11px 22px; }
.cta.ghost { background: none; border: 1px solid var(--border); color: var(--text); font-weight: 600; }
.cta.ghost:hover { background: none; border-color: var(--accent); color: var(--text); }
.audience { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin: 34px 0 0; }
.aud-card {
  display: flex; flex-direction: column; gap: 6px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 14px; padding: 22px 24px;
  text-decoration: none; color: var(--text);
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}
.aud-card:hover {
  transform: translateY(-3px); border-color: var(--accent);
  box-shadow: 0 10px 30px -14px color-mix(in srgb, var(--accent) 45%, transparent);
}
.aud-tag { color: var(--accent); font-size: .74rem; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; }
.aud-card h3 { margin: 0; font-size: 1.1rem; }
.aud-card p { color: var(--text-dim); font-size: .92rem; margin: 0; flex: 1; }
.aud-card .go { color: var(--accent); font-weight: 600; font-size: .9rem; margin-top: 8px; }
.stats {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
  margin-top: 40px; padding-top: 28px; border-top: 1px solid var(--border);
}
.stat strong { display: block; font-size: 1.7rem; color: var(--accent); letter-spacing: -.02em; font-variant-numeric: tabular-nums; }
.stat span { color: var(--text-dim); font-size: .85rem; line-height: 1.4; display: block; }

/* ---------- sections ---------- */
.section { padding: 64px 0; }
.section.alt { background: var(--bg-alt); border-block: 1px solid var(--border); }
.section h2 { font-size: 1.7rem; letter-spacing: -.01em; margin-bottom: 16px; }
.section-num { color: var(--accent); font-size: .95rem; font-weight: 600; margin-right: 10px; vertical-align: .18em; }
.section-intro { color: var(--text-dim); max-width: 44rem; margin-bottom: 34px; }

/* ---------- featured teasers (home) ---------- */
.teasers { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.teaser {
  display: flex; flex-direction: column; gap: 6px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 14px; padding: 24px;
  text-decoration: none; color: var(--text);
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}
.teaser:hover {
  transform: translateY(-4px); border-color: var(--accent);
  box-shadow: 0 10px 30px -14px color-mix(in srgb, var(--accent) 45%, transparent);
}
.teaser .case-meta { margin-bottom: 2px; }
.teaser h3 { font-size: 1.12rem; margin: 0; }
.teaser p { color: var(--text-dim); font-size: .92rem; margin: 0; flex: 1; }
.teaser .metric {
  color: var(--accent); font-weight: 700; font-size: .9rem; margin-top: 10px;
}
.teaser .go { color: var(--accent); font-weight: 600; font-size: .9rem; margin-top: 2px; }
.case-meta {
  color: var(--accent); font-size: .74rem; font-weight: 600;
  letter-spacing: .1em; text-transform: uppercase; margin-bottom: 8px;
}

/* ---------- more-work list (home) ---------- */
.more-list { list-style: none; margin: 26px 0 0; padding: 0; border-top: 1px solid var(--border); }
.more-list li {
  display: flex; gap: 14px; align-items: baseline;
  padding: 13px 4px; border-bottom: 1px solid var(--border);
  color: var(--text-dim); font-size: .95rem;
}
.more-list strong { color: var(--text); font-weight: 600; white-space: nowrap; }

/* ---------- themes / services ---------- */
.themes, .services { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.theme, .service {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; padding: 18px 20px;
}
.theme h3, .service h3 { font-size: 1rem; }
.theme p, .service p { color: var(--text-dim); font-size: .92rem; margin: 0; }
.services { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* ---------- stack ---------- */
.stack { list-style: none; display: flex; flex-wrap: wrap; gap: 10px; padding: 0; margin: 0; }
.stack li {
  border: 1px solid var(--border); background: var(--surface);
  border-radius: 999px; padding: 5px 14px; font-size: .88rem; color: var(--text-dim);
}
.stack-groups { display: grid; }
.stack-group {
  display: flex; gap: 18px; align-items: baseline;
  padding: 14px 0; border-bottom: 1px solid var(--border);
}
.stack-group:first-child { padding-top: 0; }
.stack-group:last-child { border-bottom: none; padding-bottom: 0; }
.stack-group h3 {
  flex: 0 0 160px; margin: 0; font-size: .78rem; font-weight: 600;
  letter-spacing: .12em; text-transform: uppercase; color: var(--text-dim);
}
.stack-group .stack { flex: 1; }

/* ---------- contact / footer ---------- */
.contact { text-align: center; }
.contact .lede { margin-inline: auto; }
.cta {
  display: inline-block; margin-top: 10px;
  background: var(--accent); color: var(--accent-ink);
  font-weight: 700; text-decoration: none;
  padding: 13px 28px; border-radius: 10px; font-size: 1.05rem;
}
.cta:hover { background: var(--accent-strong); }
.site-footer { border-top: 1px solid var(--border); padding: 26px 0 34px; }
.site-footer p { color: var(--text-dim); font-size: .84rem; margin: 0; }

/* ---------- case detail pages ---------- */
.case-hero { padding: 64px 0 30px; }
.case-hero h1 { font-size: clamp(1.7rem, 4vw, 2.6rem); letter-spacing: -.02em; max-width: 50rem; }
.case-hero .lede { font-size: 1.05rem; }
.crumb { color: var(--text-dim); font-size: .9rem; text-decoration: none; display: inline-block; margin-bottom: 18px; }
.crumb:hover { color: var(--text); }
.glance {
  display: flex; flex-wrap: wrap; gap: 30px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 14px; padding: 22px 26px; margin: 8px 0 26px;
}
.glance div strong { display: block; font-size: 1.45rem; color: var(--accent); letter-spacing: -.02em; }
.glance div span { color: var(--text-dim); font-size: .84rem; }
.case-body { padding-bottom: 64px; }
.case-body h2 { font-size: 1.25rem; margin: 34px 0 12px; }
.case-body h2:first-child { margin-top: 0; }
.case-body p, .case-body li { color: var(--text-dim); }
.case-body ul { padding-left: 1.15em; margin: 0 0 1em; }
.case-body li { margin-bottom: .5em; }
.case-body li strong, .case-body p strong { color: var(--text); }

/* diagrams */
.diagram {
  background: var(--bg-alt); border: 1px solid var(--border);
  border-radius: 14px; padding: 18px; margin: 10px 0 6px;
  overflow-x: auto;
}
.diagram svg { display: block; width: 100%; height: auto; min-width: 560px; }
.diagram .box { fill: var(--surface); stroke: var(--border); stroke-width: 1.5; rx: 10; }
.diagram .box-accent { fill: color-mix(in srgb, var(--accent) 14%, var(--surface)); stroke: var(--accent); }
.diagram .lbl { fill: var(--text); font: 600 13px -apple-system, "Segoe UI", Roboto, sans-serif; }
.diagram .sub { fill: var(--text-dim); font: 11.5px -apple-system, "Segoe UI", Roboto, sans-serif; }
.diagram .flow { stroke: var(--text-dim); stroke-width: 1.6; fill: none; }
.diagram .flow-accent { stroke: var(--accent); stroke-width: 1.8; fill: none; }
.diagram .flow-dashed { stroke-dasharray: 5 4; }
.diagram .arrow { fill: var(--text-dim); }
.diagram .arrow-accent { fill: var(--accent); }
.diagram-caption { color: var(--text-dim); font-size: .84rem; margin-bottom: 20px; }

/* case page prev/next */
.case-nav { display: flex; justify-content: space-between; gap: 16px; margin-top: 40px; border-top: 1px solid var(--border); padding-top: 22px; }
.case-nav a { text-decoration: none; font-weight: 600; font-size: .95rem; }

/* ---------- studio (RiverDevStudio) ---------- */
.studio-card {
  border: 1px solid color-mix(in srgb, var(--accent) 45%, var(--border));
  border-radius: 18px; padding: 34px 36px;
  background: linear-gradient(140deg, color-mix(in srgb, var(--accent) 9%, var(--surface)), var(--surface) 55%);
}
.studio-card h2 { font-size: 2rem; margin-bottom: 10px; letter-spacing: -.01em; }
.studio-card h2 .accent { color: var(--accent); }
.studio-card > p { color: var(--text-dim); max-width: 48rem; }
.studio-points { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 20px 0 4px; padding: 0; list-style: none; }
.studio-points li { color: var(--text-dim); font-size: .92rem; }
.studio-points strong { display: block; color: var(--text); margin-bottom: 2px; }
.studio-cta-row { display: flex; flex-wrap: wrap; gap: 18px; align-items: center; margin-top: 20px; }
.studio-cta-row .cta { margin-top: 0; }
.studio-cta-row .flagship { font-weight: 600; font-size: .95rem; text-decoration: none; }

/* ---------- reveal on scroll ---------- */
@media (prefers-reduced-motion: no-preference) {
  .reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
  .reveal.in { opacity: 1; transform: none; }
}

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .themes, .teasers { grid-template-columns: 1fr 1fr; }
  .stats { grid-template-columns: 1fr 1fr; gap: 24px; }
}
@media (max-width: 620px) {
  .hero { padding: 52px 0 40px; }
  .themes, .teasers, .audience, .studio-points { grid-template-columns: 1fr; }
  .studio-card { padding: 26px 22px; }
  .site-nav { gap: 10px; }
  .site-nav > a:not(.lang):not(.nav-cta) { display: none; }
  .site-nav .theme-toggle { display: none; }
  .site-nav .nav-cta, .site-nav .lang { padding: 4px 12px; font-size: .88rem; }
  .nav-burger { display: inline-grid; }
  .site-header.open .nav-burger { margin-left: auto; }
  .site-header.open .site-nav .theme-toggle { display: inline-block; }
  .stack { gap: 8px; }
  .stack li { font-size: .8rem; padding: 4px 10px; }
  .stack-group { padding: 12px 0; gap: 8px; }
  .stack-group h3 { flex: none; font-size: .72rem; letter-spacing: .1em; }
  .site-header.open .site-nav {
    position: absolute; top: 60px; left: 0; right: 0;
    flex-direction: column; align-items: stretch;
    background: var(--bg); border-bottom: 1px solid var(--border);
    padding: 6px 24px 18px; gap: 0;
    box-shadow: 0 18px 30px -18px rgba(0, 0, 0, .45);
  }
  .site-header.open .site-nav > a:not(.lang):not(.nav-cta) {
    display: block; padding: 12px 0; font-size: 1rem;
    border-bottom: 1px solid var(--border);
  }
  .site-header.open .site-nav .nav-cta,
  .site-header.open .site-nav .lang,
  .site-header.open .site-nav .theme-toggle { align-self: flex-start; margin-top: 12px; }
  .stack-group { flex-direction: column; gap: 8px; }
  .glance { gap: 20px; }
  .more-list li { flex-direction: column; gap: 2px; }
}