:root {
  --bg: #0f1729;
  --bg-soft: #16213e;
  --accent: #4f8cff;
  --accent-dark: #2f6fe0;
  --text: #1c2430;
  --muted: #6b7686;
  --card: #ffffff;
  --border: #e3e8ef;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: "Segoe UI", "Hiragino Kaku Gothic ProN", "Meiryo", system-ui, sans-serif;
  color: var(--text);
  background: #f6f8fc;
  line-height: 1.7;
}

.container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Hero */
.hero {
  background: linear-gradient(160deg, var(--bg) 0%, var(--bg-soft) 100%);
  color: #fff;
  padding: 72px 0 64px;
  text-align: center;
}

.logo {
  font-size: 44px;
  font-weight: 700;
  letter-spacing: 0.04em;
  margin: 0 0 12px;
}

.tagline {
  font-size: 18px;
  color: #c4d0e6;
  margin: 0 auto 32px;
  max-width: 620px;
}

.cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 600;
  transition: background 0.15s ease, transform 0.05s ease;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  padding: 14px 32px;
  font-size: 17px;
}

.btn-primary:hover { background: var(--accent-dark); }
.btn-primary:active { transform: translateY(1px); }

.version {
  color: #aab8d4;
  font-size: 14px;
}

.sysreq {
  margin-top: 24px;
  color: #8896b3;
  font-size: 13px;
}

/* Features */
.features { padding: 56px 0 16px; }

h2 {
  font-size: 26px;
  margin: 0 0 28px;
  text-align: center;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
}

.card h3 {
  margin: 0 0 8px;
  font-size: 17px;
  color: var(--accent-dark);
}

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

/* Changelog */
.changelog { padding: 48px 0; }

.changelog article {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 24px;
  margin-bottom: 16px;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.changelog h3 {
  margin: 0 0 8px;
  font-size: 16px;
}

.changelog ul {
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
  font-size: 14px;
}

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}

footer a { color: var(--accent-dark); }