/* ---------- Theme ---------- */
:root {
  --bg: #fafaf7;
  --surface: #ffffff;
  --text: #1d1f23;
  --muted: #5d636e;
  --accent: #2f5bea;
  --accent-hover: #2348c4;
  --border: #e3e3dd;
  --radius: 12px;
  --max: 960px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --surface: #1c1f25;
    --text: #eceef2;
    --muted: #a0a6b1;
    --accent: #7c9bff;
    --accent-hover: #9cb3ff;
    --border: #2c3038;
  }
}

/* ---------- Base ---------- */
* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

a { color: var(--accent); }
a:hover { color: var(--accent-hover); }

.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 16px;
}

/* ---------- Header / nav ---------- */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 24px;
  padding-top: 16px;
  padding-bottom: 16px;
}

.brand {
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text);
  text-decoration: none;
}

.nav { display: flex; gap: 20px; }

.nav a {
  color: var(--muted);
  text-decoration: none;
  font-weight: 500;
}

.nav a:hover,
.nav a[aria-current="page"] { color: var(--text); }

/* ---------- Main ---------- */
main { flex: 1; }

.hero {
  padding: 88px 0 72px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  line-height: 1.15;
  margin: 0 0 16px;
  letter-spacing: -0.02em;
}

.hero p {
  font-size: 1.15rem;
  color: var(--muted);
  max-width: 620px;
  margin: 0 auto 32px;
}

.button {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  padding: 12px 24px;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  transition: background 0.15s ease;
}

.button:hover { background: var(--accent-hover); color: #fff; }

.button.secondary {
  background: transparent;
  color: var(--accent);
  border: 2px solid var(--accent);
}

.button.secondary:hover { background: var(--accent); color: #fff; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  padding-bottom: 80px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.card h2 { font-size: 1.1rem; margin: 0 0 8px; }
.card p { margin: 0; color: var(--muted); }

/* ---------- Presentation page ---------- */
.page-head { padding: 56px 0 24px; }

.page-head h1 {
  font-size: clamp(1.7rem, 4vw, 2.4rem);
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}

.page-head p { color: var(--muted); margin: 0; }

.video {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius);
  overflow: hidden;
  background: #000;
  border: 1px solid var(--border);
}

.video iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.download {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin: 28px 0 80px;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.download h2 { font-size: 1.1rem; margin: 0 0 4px; }
.download p { margin: 0; color: var(--muted); font-size: 0.95rem; }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 0;
  color: var(--muted);
  font-size: 0.9rem;
  text-align: center;
}