:root {
  --bg: #202838;
  --bg-card: rgba(255, 255, 255, 0.06);
  --bg-card-hover: rgba(255, 255, 255, 0.10);
  --border: rgba(255, 255, 255, 0.10);
  --text: #ffffff;
  --text-muted: rgba(255, 255, 255, 0.70);
  --text-dim: rgba(255, 255, 255, 0.45);
  --primary: #7078F8;
  --accent: #FF8C2B;
  --green: #4DD68C;
  --sort: #7078F8;
  --search: #5CCDD1;
  --recursion: #BF8CF2;
  --max-content: 1080px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue",
               "Hiragino Sans", "Hiragino Kaku Gothic ProN",
               "BIZ UDPGothic", Meiryo, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

img { max-width: 100%; height: auto; display: block; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(32, 40, 56, 0.92);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.site-header .inner {
  max-width: var(--max-content);
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 18px;
  color: var(--text);
}
.brand-icon {
  width: 32px; height: 32px;
  border-radius: 8px;
  overflow: hidden;
}
.nav a {
  color: var(--text-muted);
  margin-left: 18px;
  font-size: 14px;
  font-weight: 500;
}
.nav a:hover { color: var(--accent); text-decoration: none; }
.lang-toggle {
  color: var(--text-dim);
  margin-left: 16px;
  font-size: 13px;
}
.lang-toggle .current { color: var(--accent); font-weight: bold; }

/* Hero */
.hero {
  max-width: var(--max-content);
  margin: 0 auto;
  padding: 64px 20px 48px;
  text-align: center;
}
.hero .dots {
  display: inline-flex;
  gap: 8px;
  margin-bottom: 14px;
}
.hero .dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: rgba(255, 255, 255, 0.85);
}
.hero .dot.accent { background: var(--accent); }
.hero h1 {
  font-size: 64px;
  font-weight: 900;
  margin: 0 0 8px;
  letter-spacing: -0.02em;
}
.hero .tagline {
  font-size: 20px;
  color: var(--text-muted);
  margin: 0 0 20px;
}
.hero .pitch {
  font-size: 17px;
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto 28px;
}
.cta-row {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}
.badge-store {
  height: 56px;
  border-radius: 12px;
  padding: 0 22px;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--border);
  color: var(--text);
  font-weight: 600;
  font-size: 16px;
}
.badge-store.disabled { opacity: 0.5; cursor: not-allowed; }
.badge-store .label-sm { display: block; font-size: 11px; color: var(--text-dim); font-weight: 400; }
.badge-store .label-lg { display: block; font-size: 17px; font-weight: 700; }
.badge-store:hover:not(.disabled) { background: var(--bg-card-hover); text-decoration: none; }

/* Sections */
section { padding: 56px 20px; }
section .inner {
  max-width: var(--max-content);
  margin: 0 auto;
}
.section-title {
  font-size: 32px;
  font-weight: 800;
  margin: 0 0 8px;
  text-align: center;
}
.section-sub {
  font-size: 16px;
  color: var(--text-muted);
  text-align: center;
  margin: 0 0 40px;
}

/* 3-pillars cards */
.pillars {
  display: grid;
  gap: 18px;
  grid-template-columns: repeat(3, 1fr);
}
@media (max-width: 760px) {
  .pillars { grid-template-columns: 1fr; }
  .hero h1 { font-size: 44px; }
  .hero .tagline { font-size: 17px; }
  .section-title { font-size: 26px; }
}
.pillar {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 24px;
}
.pillar h3 {
  margin: 12px 0 8px;
  font-size: 20px;
  font-weight: 700;
}
.pillar p { margin: 0; color: var(--text-muted); font-size: 14px; }
.pillar .icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px;
}
.pillar.sort .icon { background: rgba(112, 120, 248, 0.22); color: var(--sort); }
.pillar.search .icon { background: rgba(92, 205, 209, 0.22); color: var(--search); }
.pillar.recursion .icon { background: rgba(191, 140, 242, 0.22); color: var(--recursion); }
.pillar .badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 50px;
  background: var(--accent);
  font-size: 11px;
  font-weight: 700;
  margin-left: 6px;
  vertical-align: middle;
}

/* Feature list */
.features {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(2, 1fr);
}
@media (max-width: 760px) { .features { grid-template-columns: 1fr; } }
.feature {
  background: var(--bg-card);
  border-radius: 14px;
  padding: 18px 20px;
}
.feature h4 { margin: 0 0 6px; font-size: 16px; color: var(--accent); }
.feature p { margin: 0; color: var(--text-muted); font-size: 14px; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 20px;
  text-align: center;
  color: var(--text-dim);
  font-size: 13px;
}
.site-footer .links { margin-bottom: 8px; }
.site-footer .links a {
  color: var(--text-muted);
  margin: 0 12px;
}

/* Article (privacy / support) */
.article {
  max-width: 760px;
  margin: 0 auto;
  padding: 56px 20px;
}
.article h1 { font-size: 32px; margin: 0 0 8px; }
.article .updated { color: var(--text-dim); font-size: 13px; margin-bottom: 28px; }
.article h2 {
  margin-top: 36px;
  font-size: 20px;
  border-left: 4px solid var(--accent);
  padding-left: 10px;
}
.article p, .article li { color: var(--text-muted); font-size: 15px; }
.article ul, .article ol { padding-left: 24px; }
.article a { color: var(--accent); }
.article .contact-card {
  margin-top: 28px;
  padding: 18px 20px;
  background: var(--bg-card);
  border-radius: 14px;
  border: 1px solid var(--border);
}

/* FAQ */
.faq details {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 12px 16px;
  margin-bottom: 10px;
}
.faq summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before {
  content: "+";
  color: var(--accent);
  font-weight: bold;
  margin-right: 8px;
}
.faq details[open] summary::before { content: "−"; }
.faq details p { color: var(--text-muted); margin: 10px 0 0; font-size: 14px; }