:root {
  --bg: #0b1120;
  --bg-alt: #0f172a;
  --surface: #1e293b;
  --surface-hover: #233046;
  --border: #2a3a52;
  --text: #e6edf6;
  --muted: #93a4bd;
  --accent: #38bdf8;
  --accent-2: #818cf8;
  --radius: 12px;
  --shadow: 0 10px 30px -12px rgba(0, 0, 0, 0.6);
  --maxw: 760px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(56, 189, 248, 0.12), transparent 60%),
    radial-gradient(1000px 500px at 0% 0%, rgba(129, 140, 248, 0.10), transparent 55%),
    var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

/* ---- Header / nav ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 1.5rem;
  border-bottom: 1px solid var(--border);
  background: rgba(15, 23, 42, 0.72);
  backdrop-filter: blur(10px);
}

.brand {
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: -0.02em;
  color: var(--text);
}
.brand:hover { text-decoration: none; }
.brand span { color: var(--accent); }

.nav { display: flex; gap: 0.35rem; flex-wrap: wrap; }

.nav a {
  color: var(--muted);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.35rem 0.7rem;
  border-radius: 8px;
  transition: color 0.15s, background 0.15s;
}
.nav a:hover { color: var(--text); background: var(--surface); text-decoration: none; }
.nav a.active { color: var(--accent); background: rgba(56, 189, 248, 0.10); }

/* ---- Main ---- */
main {
  flex: 1;
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 3.5rem 1.5rem;
}

h1 {
  font-size: clamp(2rem, 5vw, 2.9rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin: 0 0 1rem;
}
h2 { font-size: 1.4rem; letter-spacing: -0.01em; margin: 2.5rem 0 0.5rem; }
h3 { margin: 0 0 0.4rem; font-size: 1.05rem; }

p { color: var(--text); }
.lead { font-size: 1.2rem; color: var(--muted); margin-top: 0; }

.gradient-text {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

code {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 0.9em;
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 0.1rem 0.4rem;
  border-radius: 6px;
}

/* ---- Buttons ---- */
.btn {
  display: inline-block;
  margin-top: 1.75rem;
  padding: 0.7rem 1.5rem;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  color: #0b1120;
  border: none;
  border-radius: 10px;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: transform 0.12s, box-shadow 0.12s;
}
.btn:hover { transform: translateY(-2px); text-decoration: none; }
.btn:active { transform: translateY(0); }

/* ---- Cards ---- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.card {
  padding: 1.4rem;
  background: linear-gradient(180deg, var(--surface), var(--bg-alt));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform 0.15s, border-color 0.15s, background 0.15s;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  background: var(--surface-hover);
}
.card p { color: var(--muted); margin: 0; }

/* ---- Form ---- */
form { margin-top: 2rem; }
.field { margin-bottom: 1.1rem; display: flex; flex-direction: column; gap: 0.4rem; }
label { color: var(--muted); font-size: 0.9rem; font-weight: 500; }

input, textarea {
  padding: 0.7rem 0.85rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-alt);
  color: var(--text);
  font: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
}
input:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.20);
}
textarea { resize: vertical; }

/* ---- Footer ---- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.75rem 1.5rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
}

/* ---- Motion ---- */
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; scroll-behavior: auto; }
}