:root {
  --bg: #0d1117;
  --bg-alt: #161b22;
  --text: #e6edf3;
  --muted: #8b949e;
  --primary: #3ea6ff;
  --primary-hover: #60b8ff;
  --card: #1b222c;
  --border: #30363d;
  --accent: #00ffa6;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: linear-gradient(180deg, var(--bg) 0%, #0a0d12 100%);
  color: var(--text);
  line-height: 1.6;
}

/* Layout */
.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: rgba(13, 17, 23, 0.75);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex; justify-content: space-between; align-items: center;
  height: 64px;
}
.brand {
  font-weight: 700; font-size: 20px;
  color: var(--text); text-decoration: none;
}
.nav a {
  color: var(--muted); text-decoration: none; margin-left: 20px;
  transition: color .2s;
}
.nav a:hover { color: var(--primary); }

/* Hero */
.hero { padding: 70px 0 40px; }
.hero-inner {
  display: grid; grid-template-columns: 1.2fr 1fr;
  gap: 40px; align-items: center;
}
.hero h1 { margin: 0 0 10px; font-size: 36px; font-weight: 700; }
.hero p { margin: 0 0 18px; color: var(--muted); }
.hero-actions { display: flex; gap: 12px; margin: 20px 0; }
.hero-meta { display: flex; gap: 14px; color: var(--muted); font-size: 14px; }

/* Buttons */
.btn {
  display: inline-block; padding: 10px 18px;
  border-radius: 8px; font-weight: 600;
  text-decoration: none; border: 1px solid var(--border);
  transition: background .2s, border-color .2s, color .2s;
}
.btn.primary {
  background: var(--primary); color: #0a0f14; border-color: transparent;
}
.btn.primary:hover { background: var(--primary-hover); }
.btn.secondary {
  background: transparent; color: var(--text);
}
.btn.secondary:hover { border-color: var(--primary); color: var(--primary); }

/* Window mock */
.hero-visual { display: flex; justify-content: center; }
.window-mock {
  max-width: 520px; border-radius: 14px; overflow: hidden;
  border: 1px solid var(--border); background: var(--card);
  box-shadow: 0 20px 60px rgba(0,0,0,0.4);
}
.window-bar {
  display: flex; align-items: center; gap: 8px;
  padding: 10px; background: #0f141b;
  border-bottom: 1px solid var(--border);
}
.window-bar .dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: #2d3748;
}
.window-bar .title { margin-left: auto; color: var(--muted); font-size: 13px; }
.window-body { padding: 10px; }

/* Tabs */
.tabbar { display: flex; gap: 8px; margin-bottom: 10px; }
.tab {
  padding: 6px 10px; border-radius: 6px;
  background: #131820; color: var(--muted); font-size: 13px;
}
.tab.active {
  background: #1f2a36; color: var(--text);
  border: 1px solid var(--primary);
}
.tab.add {
  background: transparent; border: 1px dashed var(--border);
}

/* Toolbar */
.toolbar {
  display: grid; grid-template-columns: auto auto auto 1fr;
  gap: 8px; margin-bottom: 10px;
}
.btn-icon {
  width: 36px; height: 32px; display: grid; place-items: center;
  border: 1px solid var(--border); border-radius: 6px;
  color: var(--muted); transition: .2s;
}
.btn-icon:hover { color: var(--primary); border-color: var(--primary); }
.address {
  width: 100%; height: 32px; border-radius: 6px;
  border: 1px solid var(--border); background: #0f141b;
  color: var(--text); padding: 0 10px;
}

/* Content placeholder */
.content {
  display: grid; place-items: center;
  height: 220px; border: 1px solid var(--border);
  border-radius: 10px; background: #0f141b;
}
.placeholder { color: var(--muted); font-size: 14px; }

/* Sections */
.section { padding: 56px 0; }
.section.alt {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.section h2 { margin: 0 0 18px; font-size: 28px; }

/* Cards */
.cards {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 12px; padding: 18px;
  transition: border-color .2s, transform .2s;
}
.card:hover {
  border-color: var(--primary);
  transform: translateY(-3px);
}
.card h3 { margin: 0 0 8px; font-size: 18px; }
.card p { margin: 0; color: var(--muted); }

/* Performance cards */
.perf-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.perf-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 12px; padding: 18px; text-align: center;
}
.perf-card .stat { font-size: 28px; font-weight: 600; color: var(--accent); }
.perf-card .label { color: var(--muted); }
.perf-card.highlight { border-color: var(--accent); }

/* Lists */
.download-actions { display: flex; gap: 12px; margin: 16px 0; }
.download-notes, .reqs, .roadmap { color: var(--muted); }
.download-notes li, .reqs li, .roadmap li { margin: 8px 0; }
.license { color: var(--muted); margin-top: 10px; }

/* FAQ */
.faq details {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 12px; padding: 14px 16px; margin-bottom: 10px;
}
.faq summary { cursor: pointer; font-weight: 600; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 20px 0; margin-top: 40px;
}
.footer-inner {
  display: flex; justify-content: space-between; align-items: center;
  color: var(--muted);
}
.footer-inner a { color: var(--muted); text-decoration: none; }
.footer-inner a:hover { color: var(--primary); }

/* Responsive */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .cards { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 600px) {
  .nav { display: none; }
  .cards { grid-template-columns: 1fr; }
  .perf-grid { grid-template-columns: 1fr; }
}