:root {
  --bg: #ffffff;
  --bg-soft: #f6f8fc;
  --fg: #0e1524;
  --muted: #5b6577;
  --line: #e7ebf3;
  --brand: #4f46e5;
  --brand-2: #06b6d4;
  --brand-ink: #ffffff;
  --ok: #16a34a;
  --warn: #b45309;
  --card: #ffffff;
  --shadow: 0 10px 30px rgba(16, 24, 40, .08);
  --shadow-lg: 0 24px 60px rgba(16, 24, 40, .14);
  --radius: 18px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0f17; --bg-soft: #0f1522; --fg: #e8edf6; --muted: #9aa6b8; --line: #1e2736;
    --card: #121a28; --shadow: 0 10px 30px rgba(0,0,0,.5); --shadow-lg: 0 24px 60px rgba(0,0,0,.6);
  }
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--fg);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 22px; }

/* nav */
.nav { position: sticky; top: 0; z-index: 50; background: color-mix(in srgb, var(--bg) 82%, transparent); backdrop-filter: blur(12px); border-bottom: 1px solid var(--line); }
.nav .wrap { display: flex; align-items: center; justify-content: space-between; height: 62px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; color: var(--fg); letter-spacing: .2px; }
.brand .mark { width: 26px; height: 26px; border-radius: 8px; background: linear-gradient(135deg, var(--brand), var(--brand-2)); box-shadow: 0 6px 16px rgba(79,70,229,.35); }
.nav nav { display: flex; align-items: center; gap: 20px; }
.nav nav a { color: var(--muted); font-weight: 500; font-size: .95rem; }
.nav nav a:hover { color: var(--fg); text-decoration: none; }
.nav .cta-small { padding: 8px 15px; border-radius: 10px; background: var(--fg); color: var(--bg) !important; font-weight: 700; }
@media (max-width: 760px){ .nav nav a:not(.cta-small){ display:none; } }

/* hero */
.hero { position: relative; overflow: hidden; }
.hero::before { content:""; position:absolute; inset:-30% 30% 40% -10%; background:
  radial-gradient(60% 60% at 30% 30%, rgba(79,70,229,.16), transparent 70%),
  radial-gradient(50% 50% at 80% 20%, rgba(6,182,212,.14), transparent 70%); filter: blur(6px); z-index:0; }
.hero .wrap { position: relative; z-index: 1; display: grid; grid-template-columns: 1.05fr .95fr; gap: 40px; align-items: center; padding: 66px 22px 40px; }
@media (max-width: 860px){ .hero .wrap { grid-template-columns: 1fr; padding-top: 40px; } }
.eyebrow { display:inline-flex; align-items:center; gap:8px; font-size:.82rem; font-weight:600; color:var(--brand);
  background: color-mix(in srgb, var(--brand) 12%, transparent); padding: 5px 12px; border-radius: 999px; }
.hero h1 { font-size: clamp(2rem, 4.6vw, 3.1rem); line-height: 1.12; margin: 16px 0 12px; letter-spacing: -.02em; }
.hero h1 .grad { background: linear-gradient(120deg, var(--brand), var(--brand-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p.lede { font-size: 1.12rem; color: var(--muted); margin: 0 0 22px; max-width: 34em; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.btn { display:inline-flex; align-items:center; gap:8px; padding: 13px 22px; border-radius: 12px; font-weight: 700; font-size: 1rem;
  background: var(--brand); color: var(--brand-ink); box-shadow: 0 10px 24px rgba(79,70,229,.32); }
.btn:hover { text-decoration:none; transform: translateY(-1px); }
.btn.ghost { background: transparent; color: var(--fg); border: 1px solid var(--line); box-shadow: none; }
.hero .meta { margin-top: 16px; color: var(--muted); font-size: .9rem; }
.trustline { display:flex; flex-wrap:wrap; gap: 18px; margin-top: 22px; color: var(--muted); font-size: .88rem; }
.trustline span { display:inline-flex; align-items:center; gap:7px; }
.dot { width:7px; height:7px; border-radius:50%; background: var(--ok); }

/* phone mockup */
.phone { width: 300px; max-width: 100%; aspect-ratio: 9/19; margin: 0 auto; border-radius: 40px; padding: 12px;
  background: linear-gradient(160deg, #e9edf6, #cfd7e6); box-shadow: var(--shadow-lg); }
@media (prefers-color-scheme: dark){ .phone { background: linear-gradient(160deg,#1a2434,#0d1420); } }
.screen { width:100%; height:100%; border-radius: 30px; background: var(--card); overflow:hidden; display:flex; flex-direction: column; border: 1px solid var(--line); }
.sbar { height: 30px; flex: 0 0 30px; display:flex; align-items:center; justify-content:center; color: var(--muted); font-size: 11px; border-bottom: 1px solid var(--line); }
.chat { padding: 14px; display:flex; flex-direction:column; gap: 10px; }
.bub { max-width: 84%; padding: 10px 12px; border-radius: 14px; font-size: 12.5px; line-height: 1.5; }
.bub.user { align-self: flex-end; background: var(--brand); color:#fff; border-bottom-right-radius: 4px; }
.bub.agent { align-self: flex-start; background: var(--bg-soft); color: var(--fg); border:1px solid var(--line); border-bottom-left-radius: 4px; }
.bub.tool { align-self: flex-start; background: color-mix(in srgb, var(--ok) 12%, transparent); color: var(--fg); border:1px solid color-mix(in srgb, var(--ok) 40%, transparent); font-family: ui-monospace, monospace; font-size: 11.5px; }
.typing { align-self: flex-start; display:flex; gap:4px; padding: 8px 12px; }
.typing i { width:6px; height:6px; border-radius:50%; background: var(--muted); opacity:.5; animation: b 1.2s infinite; }
.typing i:nth-child(2){ animation-delay:.2s } .typing i:nth-child(3){ animation-delay:.4s }
@keyframes b { 0%,60%,100%{ transform: translateY(0); opacity:.4 } 30%{ transform: translateY(-4px); opacity:1 } }

/* sections */
section { padding: 56px 0; }
section.soft { background: var(--bg-soft); }
.sec-head { text-align: center; max-width: 640px; margin: 0 auto 34px; }
.sec-head h2 { font-size: clamp(1.5rem, 3vw, 2rem); margin: 0 0 8px; letter-spacing: -.01em; }
.sec-head p { color: var(--muted); margin: 0; }

.grid { display: grid; gap: 18px; }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 860px){ .grid.cols-3, .grid.cols-2 { grid-template-columns: 1fr; } }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow); }
.card h3 { margin: 12px 0 6px; font-size: 1.08rem; }
.card p { margin: 0; color: var(--muted); font-size: .95rem; }
.icon { width: 42px; height: 42px; border-radius: 12px; display:grid; place-items:center; color: var(--brand-ink);
  background: linear-gradient(135deg, var(--brand), var(--brand-2)); }
.icon svg { width: 22px; height: 22px; }

.steps { counter-reset: s; }
.step { position: relative; padding-left: 58px; }
.step .n { position:absolute; left:0; top:0; width: 38px; height: 38px; border-radius: 50%; display:grid; place-items:center;
  font-weight: 800; color: var(--brand); background: color-mix(in srgb, var(--brand) 12%, transparent); }
.step h3 { margin: 4px 0 4px; }

.tiers .tier-head { display:flex; align-items:center; gap:10px; margin-bottom: 10px; }
.pill { font-size:.76rem; font-weight:700; padding: 3px 10px; border-radius: 999px; }
.pill.now { color: var(--ok); background: color-mix(in srgb, var(--ok) 14%, transparent); }
.pill.dev { color: var(--warn); background: color-mix(in srgb, var(--warn) 16%, transparent); }
.pill.no { color: var(--muted); background: color-mix(in srgb, var(--muted) 14%, transparent); }
.tiers ul { margin: 8px 0 0; padding-left: 18px; color: var(--muted); font-size: .94rem; }

/* download */
.dl { background: linear-gradient(135deg, color-mix(in srgb, var(--brand) 8%, var(--bg)), var(--bg)); border: 1px solid var(--line); border-radius: 22px; padding: 30px; box-shadow: var(--shadow); }
.dl-grid { display:grid; grid-template-columns: 1.2fr .8fr; gap: 26px; align-items:center; }
@media (max-width: 860px){ .dl-grid { grid-template-columns: 1fr; } }
.kv { list-style:none; margin: 14px 0 0; padding: 0; }
.kv li { display:flex; gap:10px; padding: 8px 0; border-bottom: 1px dashed var(--line); font-size: .9rem; }
.kv li b { min-width: 128px; color: var(--muted); font-weight: 600; }
.hash { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; word-break: break-all; font-size: .82rem; }
pre.prompt { background: var(--bg-soft); border:1px solid var(--line); border-radius: 12px; padding: 14px; white-space: pre-wrap;
  cursor: pointer; font-family: ui-monospace, monospace; font-size: .9rem; position: relative; }
pre.prompt::after { content:"点按复制"; position:absolute; top:8px; right:10px; font-size:.72rem; color: var(--muted); }
pre.prompt.copied::after { content:"已复制 ✓"; color: var(--ok); }

details { border:1px solid var(--line); border-radius: 12px; padding: 12px 16px; margin: 10px 0; background: var(--card); }
details summary { cursor: pointer; font-weight: 600; }
details p { color: var(--muted); }

.note { background: color-mix(in srgb, var(--warn) 10%, var(--bg)); border:1px solid color-mix(in srgb, var(--warn) 30%, var(--line)); color: var(--fg); padding: 12px 15px; border-radius: 12px; font-size: .92rem; }

footer { border-top: 1px solid var(--line); padding: 34px 0; color: var(--muted); }
footer .wrap { display:flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; align-items:center; }
footer a { color: var(--muted); }