:root {
  --bg: #fbfbfd;
  --surface: #ffffff;
  --text: #14141f;
  --muted: #5b5b6e;
  --line: #e6e6ef;
  --accent: #4338ca;
  --accent-soft: #eef0ff;
  --k-ring: #4338ca;
  --radius: 16px;
  --max: 1080px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d0d14;
    --surface: #15151f;
    --text: #f2f2f7;
    --muted: #a1a1b5;
    --line: #26263a;
    --accent: #a5b4fc;
    --accent-soft: #1d1f3d;
    --k-ring: #a5b4fc;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }

header.site {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--line);
}

header.site .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 600;
  font-size: 17px;
  letter-spacing: -0.01em;
}
.brand:hover { text-decoration: none; }
.brand svg { width: auto; height: 22px; display: block; }
.brand .k-letters { fill: var(--text); }
.brand .k-ring { stroke: var(--k-ring); }

nav.links { display: flex; gap: 24px; font-size: 15px; }
nav.links a { color: var(--muted); }
nav.links a:hover { color: var(--text); text-decoration: none; }

.hero { padding-top: 104px; padding-bottom: 88px; }
.hero h1 {
  font-size: clamp(38px, 6vw, 64px);
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin: 0 0 22px;
  max-width: 14ch;
}
.hero p.lead {
  font-size: clamp(17px, 2.2vw, 20px);
  color: var(--muted);
  max-width: 56ch;
  margin: 0 0 36px;
}

.btn {
  display: inline-block;
  background: var(--accent);
  color: var(--bg);
  font-weight: 600;
  padding: 13px 22px;
  border-radius: 12px;
}
.btn:hover { text-decoration: none; opacity: 0.9; }
.btn.ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--line);
  margin-left: 10px;
}

section { padding: 80px 0; border-top: 1px solid var(--line); }
section h2 {
  font-size: clamp(28px, 4vw, 38px);
  letter-spacing: -0.02em;
  line-height: 1.15;
  margin: 0 0 14px;
}
section p.sub { color: var(--muted); max-width: 60ch; margin: 0 0 40px; font-size: 18px; }

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
}
.card .icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent);
  display: grid;
  place-items: center;
  margin-bottom: 18px;
}
.card .icon svg { width: 22px; height: 22px; }
.card h3 { margin: 0 0 8px; font-size: 19px; letter-spacing: -0.01em; }
.card p { margin: 0; color: var(--muted); font-size: 16px; }

.list { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.list h3 { font-size: 18px; margin: 0 0 6px; }
.list p { margin: 0; color: var(--muted); }

.notice {
  background: var(--surface);
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  padding: 32px;
  color: var(--muted);
  font-size: 17px;
}

.contact {
  background: var(--accent-soft);
  border-radius: 24px;
  padding: 56px 48px;
  text-align: center;
}
.contact h2 { margin-bottom: 10px; }
.contact p { color: var(--muted); margin: 0 auto 28px; max-width: 48ch; font-size: 18px; }
.contact .email { font-size: clamp(20px, 3vw, 26px); font-weight: 600; }

footer.site {
  border-top: 1px solid var(--line);
  padding: 32px 0 48px;
  color: var(--muted);
  font-size: 14px;
}
footer.site .wrap { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
footer.site nav { display: flex; gap: 20px; }
footer.site a { color: var(--muted); }

.doc { padding-top: 72px; padding-bottom: 96px; max-width: 808px; }
.doc h1 { font-size: clamp(32px, 5vw, 44px); letter-spacing: -0.02em; margin: 0 0 6px; }
.doc .updated { color: var(--muted); margin: 0 0 40px; }
.doc h2 { font-size: 21px; margin: 40px 0 10px; letter-spacing: -0.01em; }
.doc p, .doc li { color: var(--text); }
.doc ul { padding-left: 22px; }

@media (max-width: 860px) {
  .grid, .list { grid-template-columns: 1fr; }
  .hero { padding-top: 72px; padding-bottom: 64px; }
  section { padding: 64px 0; }
  .contact { padding: 44px 24px; }
}

@media (max-width: 520px) {
  nav.links { gap: 16px; font-size: 14px; }
  nav.links .hide-sm { display: none; }
  .btn.ghost { margin: 12px 0 0; }
}