:root {
  --color-bg: #ffffff;
  --color-text: #1d1d1f;
  --color-muted: #6e6e73;
  --color-border: #d2d2d7;
  --color-card-bg: #f5f5f7;
  --color-accent: #0066cc;
  --color-accent-hover: #0051a3;
  --radius: 12px;
  --radius-sm: 8px;
  --max-width: 760px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  text-decoration: underline;
}

code, kbd {
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.9em;
  background: var(--color-card-bg);
  padding: 0.1em 0.4em;
  border-radius: 4px;
}

kbd {
  border: 1px solid var(--color-border);
  font-size: 0.85em;
}

/* Hero */
.hero {
  text-align: center;
  padding: 96px 24px 64px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.hero__icon {
  width: 180px;
  height: 180px;
  border-radius: 36px;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.15);
  margin-bottom: 32px;
}

.hero__title {
  font-size: 56px;
  font-weight: 700;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
}

.hero__tagline {
  font-size: 22px;
  color: var(--color-text);
  margin: 0 0 4px;
}

.hero__description {
  font-size: 18px;
  color: var(--color-muted);
  margin: 0 0 40px;
}

.hero__requirement {
  margin: 20px 0 0;
  font-size: 13px;
  color: var(--color-muted);
}

/* Button */
.button {
  display: inline-block;
  padding: 14px 32px;
  font-size: 17px;
  font-weight: 600;
  border-radius: 999px;
  text-decoration: none;
  transition: background 0.15s ease, transform 0.1s ease;
}

.button:hover {
  text-decoration: none;
}

.button--primary {
  background: var(--color-accent);
  color: white;
}

.button--primary:hover {
  background: var(--color-accent-hover);
  transform: translateY(-1px);
}

/* Section */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 64px 0;
  border-top: 1px solid var(--color-border);
}

.section__title {
  font-size: 32px;
  font-weight: 700;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}

.section__lead {
  color: var(--color-muted);
  margin: 0 0 32px;
  font-size: 17px;
}

/* Feature cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}

.card {
  background: var(--color-card-bg);
  border-radius: var(--radius);
  padding: 20px;
}

.card__title {
  font-size: 17px;
  font-weight: 600;
  margin: 0 0 6px;
}

.card__body {
  margin: 0;
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
}

.extras {
  list-style: none;
  padding: 0;
  margin: 0;
}

.extras li {
  padding: 10px 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 15px;
}

.extras li:last-child {
  border-bottom: none;
}

/* Install steps */
.steps {
  list-style: none;
  padding: 0;
  margin: 0 0 40px;
  counter-reset: step;
}

.steps__item {
  display: flex;
  gap: 20px;
  padding: 20px 0;
  border-bottom: 1px solid var(--color-border);
}

.steps__item:last-child {
  border-bottom: none;
}

.steps__num {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--color-accent);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 15px;
}

.steps__title {
  font-size: 18px;
  font-weight: 600;
  margin: 0 0 6px;
}

.steps__item p {
  margin: 0 0 6px;
  font-size: 15px;
}

.steps__hint {
  font-size: 13px;
  color: var(--color-muted);
}

.install-cta {
  text-align: center;
  margin-top: 40px;
}

/* Requirements */
.requirements {
  list-style: none;
  padding: 0;
  margin: 0;
}

.requirements li {
  padding: 10px 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 15px;
}

.requirements li:last-child {
  border-bottom: none;
}

/* Footer */
.footer {
  text-align: center;
  padding: 48px 24px 64px;
  color: var(--color-muted);
  font-size: 14px;
  border-top: 1px solid var(--color-border);
  margin-top: 32px;
}

.footer__copy {
  margin-top: 8px;
  font-size: 13px;
}

/* Mobile */
@media (max-width: 600px) {
  .hero {
    padding: 64px 20px 48px;
  }

  .hero__icon {
    width: 140px;
    height: 140px;
    border-radius: 28px;
  }

  .hero__title {
    font-size: 40px;
  }

  .hero__tagline {
    font-size: 18px;
  }

  .hero__description {
    font-size: 16px;
  }

  .section {
    padding: 48px 0;
  }

  .section__title {
    font-size: 26px;
  }

  .button {
    padding: 14px 24px;
    font-size: 16px;
  }
}