:root {
  --bg-top: #0e1730;
  --bg-bot: #060a16;
  --ink: #eef2fb;
  --muted: #97a3c2;
  --accent: #3b6fe0;
  --accent-soft: rgba(59, 111, 224, 0.12);
  --card: rgba(255, 255, 255, 0.04);
  --border: rgba(255, 255, 255, 0.10);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: radial-gradient(1200px 700px at 50% -10%, #16224a 0%, transparent 60%),
              linear-gradient(180deg, var(--bg-top), var(--bg-bot));
  background-attachment: fixed;
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* layout */
.wrap { width: 100%; max-width: 720px; margin: 0 auto; padding: 28px 24px 64px; }
.center { text-align: center; }

/* top bar: brand + language switcher */
.topbar { display: flex; align-items: center; justify-content: space-between; margin-bottom: 40px; }
.brandlink { font-weight: 700; font-size: 18px; text-decoration: none; letter-spacing: -0.01em; }
.brandlink .spec { color: var(--ink); }
.brandlink .envoy { color: var(--accent); }
.switcher { font-size: 14px; color: var(--muted); }
.switcher a { color: var(--muted); text-decoration: none; }
.switcher a:hover { color: var(--ink); }
.switcher .on { color: var(--ink); font-weight: 600; }
.switcher .sep { opacity: 0.4; margin: 0 6px; }

/* hero */
.brand { font-size: clamp(34px, 7vw, 52px); font-weight: 700; letter-spacing: -0.02em; margin-bottom: 14px; }
.brand .spec { color: var(--ink); }
.brand .envoy { color: var(--accent); }
.brand .dot { color: var(--accent); }
.hero-title { font-size: clamp(28px, 5.5vw, 40px); font-weight: 700; letter-spacing: -0.02em; margin-bottom: 14px; }
.hero-title .zh { opacity: 0.75; font-weight: 600; }
.tagline { color: var(--muted); font-size: clamp(15px, 3.6vw, 19px); margin-bottom: 36px; }

/* sections */
h2 { font-size: 22px; font-weight: 650; margin: 44px 0 14px; letter-spacing: -0.01em; }
h3 { font-size: 17px; font-weight: 650; margin: 26px 0 10px; }
p { margin-bottom: 14px; color: var(--ink); }
.muted { color: var(--muted); }
ul, ol { margin: 0 0 14px 1.2em; }
li { margin-bottom: 8px; }
a { color: var(--accent); }
hr { border: none; border-top: 1px solid var(--border); margin: 40px 0; }
.req { color: var(--muted); font-size: 14px; }
code { background: rgba(255,255,255,0.07); padding: 1px 6px; border-radius: 5px; font-size: 0.92em; }

/* product card (hub) */
.card {
  display: block; text-align: left; text-decoration: none; color: inherit;
  background: var(--card); border: 1px solid var(--border); border-radius: 16px;
  padding: 22px 24px; transition: border-color .2s, transform .2s, background .2s;
}
.card:hover { border-color: var(--accent); transform: translateY(-2px); background: var(--accent-soft); }
.card .label { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: var(--accent); margin-bottom: 8px; }
.card .name { font-size: 22px; font-weight: 650; margin-bottom: 6px; }
.card .desc { color: var(--muted); font-size: 15px; }
.card .go { margin-top: 14px; font-size: 14px; opacity: .9; }
.soon { color: var(--muted); font-size: 14px; margin-top: 26px; }

/* platform block */
.platform { background: var(--card); border: 1px solid var(--border); border-radius: 16px; padding: 22px 24px; margin-bottom: 20px; }
.platform h2 { margin-top: 0; }

/* buttons */
.btn { display: inline-block; text-decoration: none; font-weight: 600; font-size: 15px;
       padding: 11px 20px; border-radius: 10px; margin: 6px 8px 6px 0; transition: filter .15s, transform .15s; }
.btn:hover { filter: brightness(1.08); transform: translateY(-1px); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-ghost { background: transparent; color: var(--ink); border: 1px solid var(--border); }
.btn-row { margin: 18px 0 6px; }

/* callout note */
.note { background: var(--accent-soft); border-left: 3px solid var(--accent); border-radius: 8px;
        padding: 12px 16px; margin: 14px 0; font-size: 14.5px; color: var(--ink); }

/* wake-word table */
.wake { width: 100%; border-collapse: collapse; margin: 8px 0 14px; }
.wake th, .wake td { text-align: left; padding: 8px 12px; border-bottom: 1px solid var(--border); font-size: 15px; }
.wake th { color: var(--muted); font-weight: 600; font-size: 13px; text-transform: uppercase; letter-spacing: .05em; }

/* footer */
footer { margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--border); color: var(--muted); font-size: 13px; }
footer a { color: var(--muted); }
.copyright { margin-top: 10px; opacity: 0.8; }