/* kai.rmthreat.com — 界 Kai official site
   Family washi-paper system (see docs/design.md) in Kai's register:
   a single 緋 vermilion accent, the 九字 (kuji) lattice seal, sumi ink,
   Fraunces/Mincho display + Hanken/Hiragino body + mono technical labels.
   御札 (paper-ward) motif for the in-page notices. */

:root {
  /* washi surfaces */
  --paper: #F1EADB;
  --paper2: #FCF8F0;     /* card surface */
  --paper3: #F6F0E1;     /* alt surface */
  --surface-warm: #FFFDF8;

  /* sumi ink */
  --ink: #2C261C;
  --ink2: #6E6657;
  --dim: #9B9180;

  /* warm hairlines */
  --line: #E2D8C4;
  --line2: #D6CAB1;

  /* 緋 — the single Kai accent */
  --hi: #C8341A;
  --hi-ink: #8C2410;
  --hi-soft: #F7E6DF;

  /* semantic (family-aligned) */
  --ok: #4F7A3F;
  --ok-soft: #E7EEDD;
  --amber: #BE851C;
  --amber-soft: #F6ECD4;

  /* sumi dark anchor */
  --dark: #241E16;
  --dark2: #19140E;
  --on-dark: #EDE5D5;
  --on-dark-mute: #A89E8B;
  --on-dark-border: rgba(255,255,255,.10);

  --r-sm: 9px;
  --r-md: 13px;
  --r-lg: 18px;
  --shadow-sm: 0 8px 22px -14px rgba(80,60,30,.45);
  --shadow: 0 18px 42px -22px rgba(80,60,30,.50), 0 2px 6px -3px rgba(80,60,30,.16);
  --shadow-lg: 0 38px 72px -30px rgba(80,60,30,.55), 0 6px 16px -10px rgba(80,60,30,.20);
  --maxw: 1080px;

  /* display: Fraunces (family) with Mincho CJK so 界 renders in 明朝 */
  --serif: "Fraunces", "Hiragino Mincho ProN", "Yu Mincho", "Songti TC", "Noto Serif CJK TC", Georgia, serif;
  --sans: "Hanken Grotesk", system-ui, -apple-system, "Hiragino Sans", "Noto Sans CJK TC", "Noto Sans CJK JP", "PingFang TC", "Microsoft JhengHei", sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  line-height: 1.62;
  background:
    radial-gradient(900px 460px at 84% -10%, rgba(200,52,26,.06), transparent 60%),
    radial-gradient(760px 600px at -6% 8%, rgba(120,90,40,.05), transparent 55%),
    var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
/* faint washi dot-grid texture */
body::before {
  content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none; opacity: .5;
  background-image: radial-gradient(rgba(120,100,70,.05) 1px, transparent 1px);
  background-size: 4px 4px;
}

a { color: var(--hi); text-decoration: none; }
a:hover { text-decoration: underline; }
img, svg { max-width: 100%; }
::selection { background: var(--hi-soft); color: var(--hi-ink); }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.mono { font-family: var(--mono); }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(241,234,219,.82);
  backdrop-filter: saturate(140%) blur(12px);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 66px; }
.brand { display: flex; align-items: center; gap: 12px; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand .seal { width: 30px; height: 30px; color: var(--hi); flex: 0 0 auto; }
.brand .seal svg { display: block; width: 100%; height: 100%; }
.brand-name { font-family: var(--serif); font-size: 21px; font-weight: 600; letter-spacing: .02em; }
.brand-name .en { font-family: var(--mono); font-size: 12px; letter-spacing: .28em; color: var(--ink2); margin-left: 8px; }

.nav-links { display: flex; align-items: center; gap: 24px; }
.nav-links a:not(.btn) { color: var(--ink2); font-size: 14.5px; font-weight: 500; }
.nav-links a:not(.btn):hover { color: var(--ink); text-decoration: none; }

/* language selector */
.langsel { position: relative; }
.langsel-trigger {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--mono); font-size: 12.5px; color: var(--ink2);
  background: var(--surface-warm); border: 1px solid var(--line2);
  border-radius: 999px; padding: 7px 12px; cursor: pointer;
  transition: color .15s, border-color .15s, background .15s;
}
.langsel-trigger:hover { color: var(--ink); border-color: var(--dim); }
.langsel-trigger .chev { transition: transform .18s ease; opacity: .8; }
.langsel-trigger[aria-expanded="true"] { color: var(--hi); border-color: var(--hi); background: var(--hi-soft); }
.langsel-trigger[aria-expanded="true"] .chev { transform: rotate(180deg); }
.langsel-menu {
  position: absolute; top: calc(100% + 8px); right: 0; min-width: 150px;
  list-style: none; margin: 0; padding: 6px;
  background: var(--paper2); border: 1px solid var(--line); border-radius: var(--r-sm);
  box-shadow: var(--shadow); z-index: 60; animation: pop .16s ease-out;
}
.langsel-menu[hidden] { display: none; }
.langsel-menu li { display: flex; align-items: center; justify-content: space-between; padding: 9px 12px; font-size: 14px; border-radius: 7px; cursor: pointer; }
.langsel-menu li:hover { background: var(--paper3); }
.langsel-menu li.active { color: var(--hi); font-weight: 600; }
.langsel-menu li.active::after { content: "✓"; font-size: 13px; color: var(--hi); }
@keyframes pop { from { opacity: 0; transform: translateY(-6px); } to { opacity: 1; transform: translateY(0); } }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: var(--sans); font-size: 15px; font-weight: 600;
  padding: 12px 22px; border-radius: 999px; border: 1px solid transparent; cursor: pointer;
  transition: background .15s, transform .08s, border-color .15s, color .15s;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--hi); color: #fff; box-shadow: 0 14px 26px -14px rgba(200,52,26,.7); }
.btn-primary:hover { background: var(--hi-ink); transform: translateY(-1px); }
.btn-ghost { background: var(--surface-warm); color: var(--ink); border-color: var(--line2); }
.btn-ghost:hover { background: var(--paper2); border-color: var(--dim); }

/* ---------- Hero ---------- */
.hero { padding: 90px 0 80px; position: relative; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1.02fr 1fr; align-items: center; gap: 52px; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--mono); font-size: 11.5px; font-weight: 600; letter-spacing: .12em; text-transform: uppercase;
  color: var(--hi-ink); background: var(--hi-soft); border: 1px solid #E8C6BC;
  padding: 6px 13px; border-radius: 999px;
}
.eyebrow::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--hi); }
.hero h1 { font-family: var(--serif); font-size: 50px; line-height: 1.07; font-weight: 600; letter-spacing: -.02em; margin: 20px 0 18px; color: var(--ink); }
.hero p.lead { font-size: 18px; color: var(--ink2); margin: 0 0 28px; max-width: 34ch; }
.hero-cta { display: flex; gap: 13px; flex-wrap: wrap; }
.hero-note { margin-top: 20px; font-size: 13.5px; color: var(--ink2); }
.hero-note b { color: var(--ink); font-weight: 600; }

/* ---------- 御札 / banner visual ---------- */
.ofuda {
  background: var(--paper2); border: 1px solid var(--line); border-radius: var(--r-md);
  box-shadow: var(--shadow-lg); overflow: hidden;
}
/* soft gradient band instead of a single-side bar (see docs/design.md §5);
   severity is also carried by the seal/kmark colour and the state pill. */
.ofuda .kbanner { display: flex; align-items: flex-start; gap: 13px; padding: 15px 16px 15px 18px; background: linear-gradient(90deg, var(--hi-soft), transparent 40%); }
.ofuda .kbanner.warn { background: linear-gradient(90deg, var(--amber-soft), transparent 40%); }
.ofuda .kmark { display: flex; align-items: center; gap: 8px; white-space: nowrap; color: var(--hi); font-family: var(--mono); font-weight: 700; letter-spacing: .04em; font-size: 14px; }
.ofuda .kbanner.warn .kmark { color: var(--amber); }
.ofuda .kmark .seal { width: 22px; height: 22px; }
.ofuda .kbody { flex: 1; min-width: 0; }
.ofuda .ktitle { font-weight: 600; font-size: 14.5px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.state { font-family: var(--mono); font-size: 10px; letter-spacing: .08em; background: var(--hi); color: #fff; padding: 2px 9px; border-radius: 4px; }
.state.warn { background: var(--amber); }
.ofuda ul { margin: 9px 0 0; padding-left: 16px; color: var(--ink2); font-size: 12.5px; }
.ofuda ul li { margin: 4px 0; } .ofuda ul li b { color: var(--ink); font-weight: 600; }
.ofuda .blocknote { margin-top: 10px; font-family: var(--mono); font-size: 10.5px; color: var(--hi); font-weight: 700; }
.ofuda .pagebody { height: 64px; background: repeating-linear-gradient(180deg, var(--paper3) 0 22px, var(--paper) 22px 44px); }
.rid { font-family: var(--mono); color: var(--dim); font-size: .9em; }

/* ---------- Trust bar ---------- */
.trustbar { margin-top: -26px; }
.trustbar-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
  background: var(--paper2); border: 1px solid var(--line); border-radius: var(--r-md);
  box-shadow: var(--shadow-sm); padding: 24px 26px;
}
.trustbar-grid > div { text-align: center; }
.trustbar .stat { font-family: var(--serif); font-size: 25px; font-weight: 600; color: var(--ink); }
.trustbar .label { font-size: 12.5px; color: var(--ink2); margin-top: 3px; }

/* ---------- Sections ---------- */
section.block { padding: 90px 0; }
.section-head { text-align: center; max-width: 680px; margin: 0 auto 52px; }
.section-head .cap { font-family: var(--mono); font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--hi); display: block; margin-bottom: 12px; }
.section-head h2 { font-family: var(--serif); font-size: 33px; font-weight: 600; letter-spacing: -.02em; margin: 0 0 12px; color: var(--ink); }
.section-head p { font-size: 16.5px; color: var(--ink2); margin: 0; }

/* features */
.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card { background: var(--paper2); border: 1px solid var(--line); border-radius: var(--r-md); box-shadow: var(--shadow-sm); padding: 24px 22px; transition: box-shadow .18s, transform .18s; }
.card:hover { box-shadow: var(--shadow); transform: translateY(-3px); }
.card .ico { width: 44px; height: 44px; display: flex; align-items: center; justify-content: center; border-radius: 12px; background: var(--hi-soft); color: var(--hi); margin-bottom: 15px; }
.card h3 { font-family: var(--serif); font-size: 18px; margin: 0 0 8px; font-weight: 600; }
.card p { font-size: 14px; color: var(--ink2); margin: 0; }
.card .ruleid { font-family: var(--mono); font-size: 11px; color: var(--dim); margin-top: 10px; }

/* how it works — pipeline */
.pipeline-wrap { background: var(--paper3); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.pipeline { display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; counter-reset: stage; }
.stage { position: relative; background: var(--paper2); border: 1px solid var(--line); border-radius: var(--r-md); padding: 20px 16px; box-shadow: var(--shadow-sm); }
.stage .no { font-family: var(--mono); font-size: 11px; color: var(--hi); font-weight: 700; }
.stage h4 { font-family: var(--serif); font-size: 15.5px; margin: 6px 0 6px; font-weight: 600; }
.stage p { font-size: 12.5px; color: var(--ink2); margin: 0; line-height: 1.55; }
.stage:not(:last-child)::after { content: "→"; position: absolute; right: -11px; top: 50%; transform: translateY(-50%); color: var(--hi); font-weight: 700; z-index: 1; }

/* showcase (御札 states) */
.showcase { }
.gallery2 { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.gallery2 figure { margin: 0; }
.gallery2 figcaption { margin-top: 13px; text-align: center; font-size: 14px; color: var(--ink2); font-weight: 500; }

/* privacy band */
.privacy-band { background: var(--surface-warm); }
.priv-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px 28px; max-width: 880px; margin: 0 auto; }
.priv-item { display: flex; gap: 14px; background: var(--paper2); border: 1px solid var(--line); border-radius: var(--r-md); padding: 20px 22px; box-shadow: var(--shadow-sm); }
.priv-item .check { flex: 0 0 auto; width: 26px; height: 26px; border-radius: 50%; background: var(--ok-soft); color: var(--ok); display: flex; align-items: center; justify-content: center; font-size: 14px; font-weight: 700; }
.priv-item h4 { margin: 0 0 5px; font-size: 16px; font-weight: 700; color: var(--ink); }
.priv-item p { margin: 0; font-size: 13.5px; color: var(--ink2); }
.priv-cta { text-align: center; margin-top: 40px; }

/* faq */
.faq { max-width: 760px; margin: 0 auto; }
.faq details { background: var(--paper2); border: 1px solid var(--line); border-radius: var(--r-md); padding: 0 22px; margin-bottom: 13px; box-shadow: var(--shadow-sm); }
.faq summary { display: flex; align-items: center; justify-content: space-between; gap: 16px; list-style: none; cursor: pointer; padding: 19px 0; font-size: 16px; font-weight: 600; color: var(--ink); }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--hi); font-size: 23px; font-weight: 400; line-height: 1; flex: 0 0 auto; }
.faq details[open] summary::after { content: "\2013"; }
.faq details p { margin: 0 0 19px; color: var(--ink2); font-size: 14.5px; line-height: 1.7; }

/* final CTA — sumi anchor */
.cta-final { position: relative; overflow: hidden; background: linear-gradient(155deg, var(--dark) 0%, var(--dark2) 100%); color: var(--on-dark); text-align: center; padding: 92px 0; }
.cta-final::before { content: ""; position: absolute; inset: 0; background: radial-gradient(60% 120% at 50% -10%, rgba(200,52,26,.20), transparent 60%); }
.cta-final .seal-bg { position: absolute; right: 50%; transform: translateX(50%); top: 30px; width: 120px; height: 120px; color: rgba(200,52,26,.22); }
.cta-final .container { position: relative; z-index: 1; }
.cta-final h2 { font-family: var(--serif); font-size: 38px; font-weight: 600; margin: 0 0 14px; letter-spacing: -.02em; color: #fff; }
.cta-final p { font-size: 17px; color: var(--on-dark-mute); margin: 0 0 28px; }
.cta-final .cta-fine { margin-top: 18px; margin-bottom: 0; font-size: 12.5px; color: var(--on-dark-mute); }

/* footer */
.site-footer { background: var(--dark2); color: var(--on-dark-mute); padding: 62px 0 38px; }
.footer-grid { display: flex; justify-content: space-between; gap: 52px; flex-wrap: wrap; padding-bottom: 38px; border-bottom: 1px solid var(--on-dark-border); }
.footer-brand { max-width: 300px; }
.footer-brand .brand { color: #fff; margin-bottom: 13px; }
.footer-brand .brand-name { color: #fff; }
.footer-brand .brand .seal { color: var(--hi); }
.footer-brand p { margin: 0; color: var(--on-dark-mute); font-size: 13.5px; line-height: 1.65; }
.footer-cols { display: flex; gap: 60px; flex-wrap: wrap; }
.footer-col h5 { margin: 0 0 13px; font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--on-dark); }
.footer-col a { display: block; color: var(--on-dark-mute); margin-bottom: 10px; font-size: 14px; }
.footer-col a:hover { color: #fff; text-decoration: none; }
.footer-bottom { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; padding-top: 24px; font-size: 12.5px; color: var(--on-dark-mute); }
.footer-bottom .mono { font-family: var(--mono); }

/* legal pages */
.legal { max-width: 760px; margin: 0 auto; padding: 54px 24px 78px; }
.legal .back { display: inline-block; margin-bottom: 22px; font-size: 14px; font-weight: 500; }
.legal .updated { color: var(--ink2); font-size: 14px; margin-bottom: 8px; }
.legal h1 { font-family: var(--serif); font-size: 38px; font-weight: 600; letter-spacing: -.02em; margin: 0 0 10px; color: var(--ink); }
.legal .intro { font-size: 17px; color: var(--ink2); margin: 0 0 14px; }
.legal h2 { font-family: var(--serif); font-size: 21px; font-weight: 600; margin: 34px 0 10px; color: var(--ink); }
.legal p, .legal li { font-size: 15.5px; color: #433d31; }
.legal code { font-family: var(--mono); font-size: .88em; background: var(--paper3); color: var(--hi-ink); padding: 1px 6px; border-radius: 5px; }
.legal .callout {
  background:
    linear-gradient(var(--hi-soft), var(--hi-soft)) padding-box,
    linear-gradient(150deg, var(--hi), var(--line) 60%) border-box;
  border: 1px solid transparent; border-radius: var(--r-sm);
  padding: 15px 17px; margin: 18px 0; font-size: 15px;
}

/* responsive */
@media (max-width: 880px) {
  .hero { padding: 56px 0 60px; }
  .hero-grid { grid-template-columns: 1fr; gap: 36px; }
  .hero h1 { font-size: 38px; }
  .hero p.lead { max-width: none; }
  .trustbar { margin-top: 6px; }
  .trustbar-grid { grid-template-columns: repeat(2, 1fr); gap: 20px 12px; }
  .features { grid-template-columns: 1fr; }
  .pipeline { grid-template-columns: 1fr; }
  .stage:not(:last-child)::after { content: "↓"; right: 50%; top: auto; bottom: -12px; transform: translateX(50%); }
  .gallery2 { grid-template-columns: 1fr; }
  .priv-grid { grid-template-columns: 1fr; }
  .nav-links { gap: 13px; }
  .nav-links a.hide-sm { display: none; }
  .section-head h2 { font-size: 27px; }
  .cta-final h2 { font-size: 29px; }
}
@media (max-width: 520px) {
  .nav { height: auto; flex-wrap: wrap; gap: 10px; padding: 12px 0; }
  .hero h1 { font-size: 32px; }
  .brand-name .en { display: none; }
}