:root {
  --bg: #ffffff;
  --bg-alt: #f5f7fa;
  --text: #1a202c;
  --muted: #5a6577;
  --border: #e2e8f0;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-text: #ffffff;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 8px 24px rgba(0, 0, 0, 0.06);
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1420;
    --bg-alt: #161d2c;
    --text: #e6eaf2;
    --muted: #9aa5b8;
    --border: #253047;
    --accent: #60a5fa;
    --accent-hover: #93c5fd;
    --accent-text: #0f1420;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.3);
  }
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { line-height: 1.2; margin: 0 0 0.5em; letter-spacing: -0.02em; }
h1 { font-size: clamp(2.25rem, 5vw, 3.75rem); }
h2 { font-size: clamp(1.75rem, 3vw, 2.25rem); }
h3 { font-size: 1.25rem; }
p { margin: 0 0 1em; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }
code {
  font-size: 0.9em;
  padding: 0.1em 0.4em;
  border-radius: 6px;
  background: var(--bg-alt);
  border: 1px solid var(--border);
}

.container { width: min(1100px, 100% - 2rem); margin-inline: auto; }
.narrow { width: min(640px, 100% - 2rem); }
.center { text-align: center; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.nav nav { display: flex; align-items: center; gap: 1.5rem; }
.nav nav a:not(.btn) { color: var(--muted); font-weight: 500; }
.nav nav a:not(.btn):hover { color: var(--text); }
.logo { display: flex; align-items: center; gap: 0.6rem; font-weight: 700; font-size: 1.15rem; color: var(--text); }
.logo-mark {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--accent);
  color: var(--accent-text);
  font-size: 1rem;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.4rem;
  border-radius: 999px;
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 600;
  border: 1px solid var(--accent);
  transition: background 0.15s, transform 0.15s;
}
.btn:hover { background: var(--accent-hover); color: var(--accent-text); transform: translateY(-1px); }
.btn-small { padding: 0.45rem 1rem; font-size: 0.95rem; }
.btn-ghost { background: transparent; color: var(--text); border-color: var(--border); }
.btn-ghost:hover { background: var(--bg-alt); color: var(--text); }

/* Hero */
.hero {
  padding: clamp(4rem, 12vw, 8rem) 0;
  background:
    radial-gradient(circle at 15% 20%, color-mix(in srgb, var(--accent) 14%, transparent), transparent 45%),
    radial-gradient(circle at 85% 60%, color-mix(in srgb, var(--accent) 10%, transparent), transparent 40%);
}
.hero h1 { max-width: 16ch; }
.eyebrow { text-transform: uppercase; letter-spacing: 0.12em; font-size: 0.8rem; font-weight: 700; color: var(--accent); }
.lead { font-size: 1.2rem; color: var(--muted); max-width: 60ch; }
.actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 2rem; }

/* Sections */
.section { padding: clamp(3.5rem, 8vw, 6rem) 0; }
.section-alt { background: var(--bg-alt); border-block: 1px solid var(--border); }

.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
.card {
  padding: 1.75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  box-shadow: var(--shadow);
}
.card p { color: var(--muted); margin: 0; }
.card-icon { font-size: 1.75rem; margin-bottom: 0.75rem; }

.split { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 3rem; align-items: center; }
.checklist { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.75rem; }
.checklist li { padding-left: 2rem; position: relative; }
.checklist li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0.1em;
  width: 1.4rem;
  height: 1.4rem;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--accent);
  color: var(--accent-text);
  font-size: 0.8rem;
  font-weight: 700;
}

/* Footer */
.site-footer { padding: 2rem 0; border-top: 1px solid var(--border); color: var(--muted); font-size: 0.95rem; }
.site-footer p { margin: 0; }

/* 404 */
.not-found { min-height: 70vh; display: grid; place-items: center; text-align: center; }
.not-found .code { font-size: clamp(5rem, 18vw, 9rem); font-weight: 800; color: var(--accent); margin: 0; line-height: 1; }

@media (max-width: 600px) {
  .nav nav a:not(.btn) { display: none; }
}