:root {
  --canvas: #eaf6ff;
  --canvas-deep: #d4ecff;
  --surface: #ffffff;
  --ink: #24334f;
  --ink-soft: #5a6b86;
  --sky: #2e86de;
  --sky-deep: #1c5fb0;
  --grass: #34c759;
  --accent: #ff9f1c;
  --border: #cfe4f7;
  --radius: 18px;
  --shadow: 0 10px 30px rgba(36, 51, 79, 0.10);
  --maxw: 860px;
}

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: linear-gradient(180deg, var(--canvas-deep), var(--canvas));
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--sky-deep); }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(234, 246, 255, 0.9);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 12px;
  padding-bottom: 12px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--ink);
  text-decoration: none;
}
.brand .dot { font-size: 1.3rem; }

.nav { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.nav a { color: var(--ink-soft); text-decoration: none; font-weight: 600; }
.nav a.active, .nav a:hover { color: var(--sky-deep); }

.lang-switch { display: inline-flex; align-items: center; gap: 8px; }
.lang-switch select {
  font: inherit;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 12px;
  cursor: pointer;
}
.sr-label {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

/* Hero */
.hero { text-align: center; padding: 56px 0 24px; }
.hero .icon { font-size: 4rem; line-height: 1; }
.hero h1 { font-size: 2.4rem; margin: 12px 0 6px; }
.tagline { font-size: 1.25rem; color: var(--sky-deep); font-weight: 700; margin: 0 0 10px; }
.hero-sub { max-width: 640px; margin: 0 auto 6px; color: var(--ink-soft); }
.rule { width: 120px; height: 6px; border-radius: 6px; background: var(--accent); margin: 18px auto; }

.btn {
  display: inline-block;
  background: var(--sky);
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  padding: 12px 22px;
  border-radius: 999px;
  margin: 6px;
  box-shadow: var(--shadow);
}
.btn.secondary { background: var(--surface); color: var(--sky-deep); border: 1px solid var(--border); }

/* Sections */
.section-title { text-align: center; margin-top: 40px; font-size: 1.6rem; }
.section-sub { text-align: center; color: var(--ink-soft); max-width: 620px; margin: 6px auto 24px; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin: 8px 0 8px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
}
.card .emoji { font-size: 2rem; }
.card h3 { margin: 10px 0 6px; font-size: 1.1rem; }
.card p { margin: 0; color: var(--ink-soft); }

/* Docs (privacy/support) */
.doc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  margin: 32px 0;
}
.doc h1 { margin-top: 0; }
.doc h2 { margin-top: 26px; font-size: 1.25rem; }
.doc .updated { color: var(--ink-soft); font-size: 0.95rem; margin-top: -6px; }
.email { font-weight: 700; }

.faq { margin: 8px 0 24px; }
.faq details {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 6px 20px;
  margin-bottom: 12px;
  box-shadow: var(--shadow);
}
.faq summary {
  cursor: pointer;
  font-weight: 700;
  padding: 12px 0;
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "＋"; float: right; color: var(--sky-deep); }
.faq details[open] summary::after { content: "－"; }
.faq p { margin: 0 0 14px; color: var(--ink-soft); }

/* Footer */
.site-footer {
  margin-top: 48px;
  border-top: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.5);
}
.site-footer .wrap { padding: 26px 20px; text-align: center; color: var(--ink-soft); }
.site-footer .links { display: flex; gap: 18px; justify-content: center; margin-bottom: 8px; flex-wrap: wrap; }
.site-footer .links a { color: var(--ink-soft); text-decoration: none; font-weight: 600; }
.site-footer .links a:hover { color: var(--sky-deep); }

@media (max-width: 560px) {
  .hero h1 { font-size: 1.9rem; }
  .site-header .wrap { flex-direction: column; align-items: stretch; }
  .nav { justify-content: center; }
}