*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --accent: #007AFF;
  --text-primary: #1c1c1e;
  --text-secondary: #6e6e73;
  --border: #d1d1d6;
  --bg: #ffffff;
  --bg-secondary: #f2f2f7;
}

html {
  font-size: 16px;
}

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

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

a:hover {
  text-decoration: underline;
}

/* Header */
header {
  border-bottom: 1px solid var(--border);
  padding: 16px 24px;
}

.header-inner {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 12px;
}

.header-app-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
}

.header-nav {
  margin-left: auto;
  display: flex;
  gap: 20px;
}

.header-nav a {
  font-size: 14px;
  color: var(--text-secondary);
}

.header-nav a:hover {
  color: var(--accent);
  text-decoration: none;
}

/* Main */
main {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 24px 80px;
}

/* Page title */
h1 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
  letter-spacing: -0.3px;
}

.page-meta {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 40px;
}

/* Sections */
h2 {
  font-size: 17px;
  font-weight: 600;
  margin-top: 36px;
  margin-bottom: 10px;
}

p {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

ul, ol {
  padding-left: 20px;
  margin-bottom: 12px;
}

li {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

/* Divider */
hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 40px 0;
}

/* Contact box */
.contact-box {
  background: var(--bg-secondary);
  border-radius: 12px;
  padding: 20px 24px;
  margin-top: 16px;
}

.contact-box p {
  margin-bottom: 4px;
}

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 24px;
  text-align: center;
}

footer p {
  font-size: 13px;
  color: var(--text-secondary);
  margin: 0;
}

/* Support FAQ */
.faq-item {
  border-top: 1px solid var(--border);
  padding: 20px 0;
}

.faq-item:last-child {
  border-bottom: 1px solid var(--border);
}

.faq-q {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.faq-a {
  font-size: 15px;
  color: var(--text-secondary);
  margin: 0;
}

/* Responsive */
@media (max-width: 600px) {
  h1 {
    font-size: 22px;
  }

  main {
    padding: 32px 20px 60px;
  }
}