:root {
  --bg: #0a0d12;
  --bg-2: #121923;
  --card: #1a2431;
  --line: #2a3a4e;
  --text: #e7eef7;
  --muted: #9cb0c7;
  --accent: #2da7ff;
  --accent-2: #7cd0ff;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
  background: linear-gradient(180deg, var(--bg), var(--bg-2));
  color: var(--text);
  font-family: Inter, Segoe UI, Roboto, Arial, sans-serif;
  line-height: 1.5;
}

a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  width: min(1100px, 92vw);
  margin: 0 auto;
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: rgba(10, 13, 18, 0.85);
  backdrop-filter: blur(4px);
  position: sticky;
  top: 0;
}

.nav-wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 1rem 0;
}

.brand {
  color: var(--text);
  font-weight: 700;
  letter-spacing: 0.03em;
}

nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

nav a[aria-current="page"] {
  color: var(--text);
  border-bottom: 2px solid var(--accent);
}

.hero {
  padding: 5rem 0 3rem;
  border-bottom: 1px solid var(--line);
}

h1 {
  font-size: clamp(2rem, 4vw, 3.4rem);
  margin: 0 0 0.8rem;
  line-height: 1.1;
}

h2 { margin-top: 0; }

.lead {
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.3rem);
}

.section { padding: 2.5rem 0; }

.cta-grid,
.three-col {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.stack {
  display: grid;
  gap: 1rem;
}

.card,
.sub-card {
  border: 1px solid var(--line);
  background: var(--card);
  border-radius: 12px;
  padding: 1rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.85rem 1.2rem;
  border-radius: 10px;
  border: 1px solid var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.btn-primary {
  background: var(--accent);
  color: #06111f;
}

.btn-primary:hover {
  background: #58bbff;
  text-decoration: none;
}

.table-wrap { overflow-x: auto; }

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  border: 1px solid var(--line);
  padding: 0.65rem;
  text-align: left;
}

th { background: #223246; }

label {
  display: grid;
  gap: 0.35rem;
  margin-bottom: 0.8rem;
  font-weight: 500;
}

input, select, textarea {
  background: #0f1722;
  border: 1px solid var(--line);
  color: var(--text);
  border-radius: 8px;
  padding: 0.7rem;
  font: inherit;
}

.site-footer {
  border-top: 1px solid var(--line);
  padding: 1.2rem 0;
  margin-top: 2rem;
}

.footer-grid {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.mono,
.formula {
  font-family: Consolas, Menlo, Monaco, monospace;
  font-weight: 700;
  letter-spacing: 0.02em;
}

@media (max-width: 850px) {
  .cta-grid,
  .three-col {
    grid-template-columns: 1fr;
  }

  .nav-wrap {
    flex-direction: column;
    align-items: flex-start;
  }
}