:root {
  --bg: #f7f7f8;
  --card: #ffffff;
  --border: #e5e5e5;
  --text: #1c1c1e;
  --muted: #555;
  --hint: #808085;
  --accent: #6d28d9;
  --accent-hover: #5b21b6;
  --accent-contrast: #ffffff;
  --hover: #ececee;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1c1d1f;
    --card: #26272b;
    --border: #3b3c40;
    --text: #ececee;
    --muted: #b4b4b9;
    --hint: #8e8e94;
    --accent: #8b5cf6;
    --accent-hover: #7c3aed;
    --accent-contrast: #ffffff;
    --hover: #2e2f33;
    color-scheme: dark;
  }
}

* {
  box-sizing: border-box;
}
body {
  margin: 0;
  font-family:
    system-ui,
    -apple-system,
    'Segoe UI',
    'Hiragino Sans',
    'Noto Sans JP',
    sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
main {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 20px 60px;
}
img {
  max-width: 100%;
}

/* Header */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 880px;
  margin: 0 auto;
  padding: 20px;
  gap: 16px;
  flex-wrap: wrap;
}
.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  color: inherit;
  text-decoration: none;
  font-weight: 700;
  font-size: 18px;
}
.site-header nav {
  display: flex;
  gap: 20px;
}
.site-header nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 15px;
}
.site-header nav a:hover {
  color: var(--text);
}

/* Hero */
.hero {
  text-align: center;
  padding: 40px 0 32px;
}
.hero img {
  display: block;
  margin: 0 auto 16px;
}
.hero h1 {
  font-size: 34px;
  margin: 0 0 12px;
}
.hero p {
  color: var(--muted);
  font-size: 18px;
  max-width: 560px;
  margin: 0 auto;
}

/* Install buttons */
.install-buttons {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin: 28px 0;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
  border: 1px solid var(--border);
}
.btn-primary {
  background: var(--accent);
  color: var(--accent-contrast);
  border-color: var(--accent);
}
.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}
.btn-secondary {
  background: var(--card);
  color: var(--text);
}
.btn-secondary:hover {
  background: var(--hover);
}

/* Sections */
h2 {
  font-size: 22px;
  margin: 48px 0 20px;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.features li {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 20px;
}
.features strong {
  display: block;
  margin-bottom: 6px;
}
.features span {
  color: var(--muted);
  font-size: 15px;
}

.steps {
  padding-left: 22px;
}
.steps li {
  margin-bottom: 10px;
}

/* Privacy / plain content pages */
.page h1 {
  font-size: 28px;
}
.page h2 {
  font-size: 20px;
}
.page ul {
  padding-left: 22px;
}

/* Footer */
.site-footer {
  max-width: 880px;
  margin: 0 auto;
  padding: 24px 20px 40px;
  color: var(--hint);
  font-size: 14px;
  border-top: 1px solid var(--border);
}
.site-footer a {
  color: inherit;
}

@media (max-width: 600px) {
  .hero h1 {
    font-size: 27px;
  }
  .hero p {
    font-size: 16px;
  }
}