:root {
  color-scheme: dark;
  --bg: #0b0d10;
  --bg-2: #11151a;
  --line: #222932;
  --text: #e8ebef;
  --muted: #9aa4af;
  --accent: #7cf29a;
  --accent-ink: #06210f;
  --amber: #ffc46b;
  --radius: 12px;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 var(--sans);
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
h1, h2, h3 { line-height: 1.2; margin: 0; letter-spacing: -0.01em; }
h2 { font-size: clamp(24px, 3.4vw, 34px); margin-bottom: 28px; max-width: 760px; }
h3 { font-size: 17px; margin-bottom: 8px; }
p { margin: 0; }
.wrap { max-width: 1120px; margin: 0 auto; padding: 0 20px; }
.muted { color: var(--muted); }
section { padding: 88px 0; border-top: 1px solid var(--line); }

/* nav */
.nav {
  position: sticky; top: 0; z-index: 10;
  background: rgba(11, 13, 16, 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav-in { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: 0.04em; }
.logo-mark {
  display: grid; place-items: center; width: 28px; height: 28px; border-radius: 7px;
  background: var(--accent); color: var(--accent-ink); font-family: var(--mono); font-size: 15px;
}
.nav-links { display: flex; align-items: center; gap: 22px; font-size: 14px; color: var(--muted); }
.nav-links a:hover { color: var(--text); }
.nav-cta { color: var(--text) !important; }
.lang {
  font: inherit; color: var(--text); background-color: transparent; cursor: pointer;
  border: 1px solid var(--line); border-radius: 999px; padding: 4px 26px 4px 12px;
  appearance: none; -webkit-appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, var(--muted) 50%), linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position: calc(100% - 15px) 55%, calc(100% - 10px) 55%;
  background-size: 5px 5px; background-repeat: no-repeat;
}
.lang option { color: var(--text); background: var(--bg); }
.lang:hover { border-color: var(--muted); }

/* hero */
.hero { border-top: 0; padding: 96px 0 88px; }
.hero-in { display: grid; grid-template-columns: 1.05fr 1fr; gap: 56px; align-items: center; }
.kicker { color: var(--accent); font-family: var(--mono); font-size: 13px; letter-spacing: 0.02em; margin-bottom: 18px; }
h1 { font-size: clamp(36px, 5.6vw, 60px); font-weight: 750; margin-bottom: 22px; }
.sub { color: var(--muted); font-size: 18px; max-width: 560px; }
.ctas { display: flex; flex-wrap: wrap; gap: 12px; margin: 32px 0 18px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  height: 46px; padding: 0 22px; border-radius: 10px; font-weight: 600; font-size: 15px;
  border: 1px solid transparent; cursor: pointer; font-family: inherit;
}
.btn.primary { background: var(--accent); color: var(--accent-ink); }
.btn.primary:hover { filter: brightness(1.06); }
.btn.ghost { border-color: var(--line); color: var(--text); }
.btn.ghost:hover { border-color: var(--muted); }
.note { color: var(--muted); font-size: 13px; }

.term {
  background: #07090b; border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: 0 30px 80px -40px rgba(124, 242, 154, 0.25);
  overflow: hidden; min-width: 0;
}
.term-bar { display: flex; align-items: center; gap: 7px; padding: 12px 14px; border-bottom: 1px solid var(--line); }
.term-bar i { width: 10px; height: 10px; border-radius: 50%; background: #2a313a; }
.term-bar span { margin-left: 8px; color: var(--muted); font: 12px var(--mono); }
.term pre { margin: 0; padding: 20px 22px; overflow-x: auto; font: 13.5px/1.75 var(--mono); color: #cfd6dd; }
.term .p { color: var(--muted); }
.term .ok { color: var(--accent); }
.term .mic { color: #ff6b6b; }
.term .s { color: var(--amber); }
.term .j { color: #8ec5ff; }

/* cards */
.cards { display: grid; gap: 16px; }
.cards.three { grid-template-columns: repeat(3, 1fr); }
.cards.four { grid-template-columns: repeat(4, 1fr); }
.tag { display: block; font: 12px var(--mono); letter-spacing: 0.08em; color: var(--accent); margin-bottom: 10px; }
.senses h2, .easy h2, .battery h2, .fit h2 { margin-bottom: 10px; }
.timeline { margin-top: 22px; color: var(--muted); font-size: 15px; max-width: 760px; }
.timeline::before { content: "⟷ "; color: var(--accent); }
.probe-note { margin: 16px 0 0; padding: 18px 24px; background: var(--bg-2); border: 1px solid var(--line); border-left: 3px solid var(--accent); border-radius: var(--radius); color: var(--muted); font-size: 15px; }
.probe-note strong { color: var(--text); }
.card { background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; }
.card p { color: var(--muted); font-size: 15px; }

/* steps */
.steps { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; counter-reset: s; }
.step { position: relative; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; }
.step p { color: var(--muted); font-size: 15px; }
.step.accent { border-color: rgba(124, 242, 154, 0.45); background: linear-gradient(180deg, rgba(124, 242, 154, 0.07), var(--bg-2) 60%); }
.num {
  display: inline-grid; place-items: center; width: 28px; height: 28px; border-radius: 50%;
  border: 1px solid var(--line); font: 13px var(--mono); color: var(--muted); margin-bottom: 16px;
}
.step.accent .num { border-color: var(--accent); color: var(--accent); }
.loop { margin-top: 22px; color: var(--muted); font-size: 15px; }
.loop::before { content: "↺ "; color: var(--accent); }

/* specs */
.specs h2 { margin-bottom: 10px; }
.spec-list { margin: 28px 0 0; border-top: 1px solid var(--line); }
.spec-list > div { display: grid; grid-template-columns: 220px 1fr; gap: 24px; padding: 16px 0; border-bottom: 1px solid var(--line); }
.spec-list dt { color: var(--muted); font-size: 15px; }
.spec-list dd { margin: 0; font-size: 15px; }

/* open */
.open-in > * { max-width: 760px; }
.open p { color: var(--muted); font-size: 18px; }
.open h2 { margin-bottom: 16px; }

/* access */
.access-in { display: grid; grid-template-columns: 1fr 1.1fr; gap: 56px; align-items: start; }
.access h2 { margin-bottom: 12px; }
.form { display: grid; gap: 16px; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; }
.form label { display: grid; gap: 6px; font-size: 14px; color: var(--muted); }
.form input, .form select, .form textarea {
  font: 15px var(--sans); color: var(--text); background: var(--bg);
  border: 1px solid var(--line); border-radius: 9px; padding: 11px 12px; width: 100%;
}
.form input:focus, .form select:focus, .form textarea:focus { outline: 2px solid rgba(124, 242, 154, 0.5); border-color: transparent; }
.form textarea { resize: vertical; }
.form .btn { width: 100%; }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.fine { font-size: 12.5px; color: var(--muted); }
.status { font-size: 14px; min-height: 1.4em; }
.status.ok { color: var(--accent); }
.status.err { color: #ff8a8a; }

/* footer */
.foot { border-top: 1px solid var(--line); padding: 28px 0 40px; color: var(--muted); font-size: 13px; }
.foot-in { display: flex; justify-content: space-between; }

@media (max-width: 900px) {
  .hero-in, .access-in { grid-template-columns: 1fr; gap: 40px; }
  .cards.three { grid-template-columns: 1fr; }
  .cards.four { grid-template-columns: 1fr 1fr; }
  .steps { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 560px) {
  section { padding: 64px 0; }
  .hero { padding: 56px 0 64px; }
  .nav-links a:not(.nav-cta) { display: none; }
  .steps { grid-template-columns: 1fr; }
  .cards.four { grid-template-columns: 1fr; }
  .spec-list > div { grid-template-columns: 1fr; gap: 4px; }
  .term pre { font-size: 12px; padding: 16px; }
  .sub { font-size: 16px; }
}

/* hero art */
.hero-art { margin: 0; min-width: 0; }
.hero-art .art { width: 100%; height: auto; display: block; filter: drop-shadow(0 40px 60px rgba(124, 242, 154, 0.08)); }
.hero-art figcaption { margin-top: 6px; text-align: center; color: var(--muted); font-size: 12px; }
svg text { font-family: var(--sans); }
svg text.mono { font-family: var(--mono); }

/* before / after */
.ba h2 { margin-bottom: 10px; }
.lead { margin-bottom: 28px; }
.ba-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.panel { margin: 0; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 8px; }
.panel.after { border-color: rgba(124, 242, 154, 0.45); }
.panel svg { width: 100%; height: auto; display: block; }

/* commands */
.cmd-row { display: grid; grid-template-columns: 1fr 1.15fr; gap: 48px; align-items: center; margin-top: 56px; }
.cmd-title { font-size: 22px; margin-bottom: 12px; }
.cmd-row .muted { font-size: 16px; }

/* open source pills */
.pills { list-style: none; padding: 0; margin: 24px 0 0; display: flex; flex-wrap: wrap; gap: 10px; }
.pills li { border: 1px solid var(--line); border-radius: 999px; padding: 6px 14px; font-size: 14px; color: var(--text); }
.pills li:last-child { border-color: rgba(124, 242, 154, 0.55); color: var(--accent); }

@media (max-width: 900px) {
  .ba-grid, .cmd-row { grid-template-columns: 1fr; gap: 24px; }
}

/* PPK2 comparison */
.compare h2 { margin-bottom: 10px; }
.cmp-wrap { overflow-x: auto; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); }
.cmp { width: 100%; border-collapse: collapse; font-size: 15px; }
.cmp th, .cmp td { padding: 13px 18px; text-align: left; vertical-align: top; border-bottom: 1px solid var(--line); }
.cmp tbody tr:last-child th, .cmp tbody tr:last-child td { border-bottom: 0; }
.cmp thead th { font: 12px var(--mono); letter-spacing: 0.08em; color: var(--muted); }
.cmp thead th.us { color: var(--accent); }
.cmp tbody th { width: 46%; font-weight: 400; color: var(--text); }
.cmp td { width: 27%; color: var(--muted); }
.cmp td.y { color: var(--accent); }
.cmp-src { margin-top: 12px; font-size: 12.5px; color: var(--muted); }
.probe-note a { color: var(--accent); white-space: nowrap; }
.access .probe-note { margin-top: 24px; }

/* pilot checkbox and follow-up question */
.form label.check { display: flex; align-items: flex-start; gap: 10px; color: var(--text); }
.form label.check input { flex: none; width: 18px; height: 18px; margin: 2px 0 0; padding: 0; accent-color: var(--accent); }
.followup { display: grid; gap: 12px; padding: 16px; border: 1px solid rgba(124, 242, 154, 0.45); border-radius: 10px; font-size: 15px; }
.followup[hidden] { display: none; }
.fu-btns { display: flex; gap: 10px; }
.form .fu-btns .btn { width: auto; flex: 1; }

@media (max-width: 560px) {
  .cmp th, .cmp td { padding: 11px 12px; font-size: 14px; }
}