:root {
  --brand: #10b981;
  --brand-dark: #047857;
  --ink: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --bg: #ffffff;
  --soft: #f1f5f9;
  --radius: 14px;
  --max: 980px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "PingFang TC", "Hiragino Sans GB", "Microsoft YaHei", "Microsoft JhengHei",
    Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

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

/* ---------- language switch (en / zh / zh-Hant) ---------- */
body:not([data-lang="en"]) [data-lang="en"] { display: none !important; }
body:not([data-lang="zh"]) [data-lang="zh"] { display: none !important; }
body:not([data-lang="zh-Hant"]) [data-lang="zh-Hant"] { display: none !important; }

/* ---------- layout ---------- */
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 22px; }

header.site {
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(12px);
  position: sticky;
  top: 0;
  z-index: 20;
}

.nav {
  display: flex;
  align-items: center;
  gap: 18px;
  height: 62px;
}

.logo {
  font-weight: 700;
  font-size: 17px;
  letter-spacing: -0.2px;
  display: flex;
  align-items: center;
  gap: 9px;
  margin-right: auto;
}

.logo .dot {
  width: 22px;
  height: 22px;
  border-radius: 7px;
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  display: inline-block;
}

.nav a.navlink { color: var(--muted); font-size: 14.5px; font-weight: 500; }
.nav a.navlink:hover, .nav a.navlink.active { color: var(--ink); text-decoration: none; }

.langsel {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 999px;
  padding: 5px 10px;
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  cursor: pointer;
  outline: none;
  font-family: inherit;
  line-height: 1.4;
}
.langsel:hover { border-color: var(--brand); color: var(--ink); }
.langsel:focus-visible { border-color: var(--brand); box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.18); }

/* ---------- hero ---------- */
.hero { padding: 66px 0 40px; text-align: center; }

.hero h1 {
  font-size: clamp(30px, 5vw, 46px);
  line-height: 1.2;
  letter-spacing: -0.9px;
  margin: 0 0 14px;
}

.hero p.lede {
  font-size: clamp(15px, 2.2vw, 18px);
  color: var(--muted);
  max-width: 620px;
  margin: 0 auto 26px;
}

.cta {
  display: inline-block;
  background: var(--brand);
  color: #fff;
  font-weight: 600;
  font-size: 15.5px;
  padding: 12px 26px;
  border-radius: 999px;
  box-shadow: 0 8px 20px rgba(16, 185, 129, 0.28);
}
.cta:hover { background: var(--brand-dark); text-decoration: none; }

.byline {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 13.5px;
  letter-spacing: 0.1px;
}

/* ---------- features ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 16px;
  padding: 26px 0 10px;
}

.card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  background: #fff;
}

.card h3 { margin: 0 0 7px; font-size: 16px; }
.card p { margin: 0; color: var(--muted); font-size: 14px; }

/* ---------- screenshots ---------- */
.shots {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  padding: 18px 0 8px;
}

.shots img {
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  display: block;
}

.section-title {
  font-size: 21px;
  margin: 46px 0 6px;
  letter-spacing: -0.3px;
}

.section-sub { color: var(--muted); font-size: 14.5px; margin: 0 0 6px; }

/* ---------- content pages ---------- */
.doc { padding: 44px 0 60px; }
.doc h1 { font-size: clamp(26px, 4vw, 34px); letter-spacing: -0.6px; margin: 0 0 8px; }
.doc h2 { font-size: 19px; margin: 34px 0 8px; }
.doc p, .doc li { color: #334155; font-size: 15px; }
.doc ul { padding-left: 20px; }
.doc .updated { color: var(--muted); font-size: 13.5px; margin: 0 0 26px; }

.contact {
  border: 1px solid var(--line);
  border-left: 3px solid var(--brand);
  border-radius: var(--radius);
  padding: 18px 20px;
  background: var(--soft);
  margin: 22px 0 8px;
}
.contact strong { display: block; margin-bottom: 4px; }
.contact a { font-weight: 600; font-size: 16px; }

details.faq {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0;
  margin-bottom: 10px;
  overflow: hidden;
}
details.faq summary {
  cursor: pointer;
  padding: 15px 18px;
  font-weight: 600;
  font-size: 15px;
  list-style: none;
}
details.faq summary::-webkit-details-marker { display: none; }
details.faq summary::after { content: "+"; float: right; color: var(--muted); font-weight: 700; }
details.faq[open] summary::after { content: "\2212"; }
details.faq .body { padding: 0 18px 16px; font-size: 14.5px; color: #334155; }
details.faq .body p { margin: 0 0 8px; }
details.faq .body p:last-child { margin-bottom: 0; }

footer.site {
  border-top: 1px solid var(--line);
  margin-top: 40px;
  padding: 26px 0 40px;
  color: var(--muted);
  font-size: 13.5px;
}
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 16px; align-items: center; }
footer.site nav { margin-left: auto; display: flex; gap: 16px; }

@media (max-width: 560px) {
  .hero { padding: 44px 0 28px; }
  .nav { gap: 12px; }
  .nav a.navlink { font-size: 13.5px; }
}