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

:root {
  --color-bg: #0e1117;
  --color-surface: #161b22;
  --color-surface-hover: #1c2230;
  --color-text: #e6edf3;
  --color-text-secondary: #8b949e;
  --color-accent: #00a6fe;
  --color-accent-hover: #3dbfff;
  --color-warm: #ff9400;
  --color-border: #21262d;
  --font-sans: -apple-system, BlinkMacSystemFont, "Hiragino Sans",
    "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  --max-width: 720px;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.8;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

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

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

/* Header */
.header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.header-logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.header-logo:hover {
  text-decoration: none;
  color: var(--color-text);
}

.header-logo img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

nav {
  display: flex;
  gap: 1.25rem;
  font-size: 0.875rem;
}

nav a {
  color: var(--color-text-secondary);
  white-space: nowrap;
}

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

/* Main */
main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
  width: 100%;
}

/* Hero (top page) */
.hero {
  text-align: center;
  padding: 3rem 0 2rem;
}

.hero h1 {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}

.hero .subtitle {
  color: var(--color-text-secondary);
  font-size: 1rem;
  margin-bottom: 2rem;
}

.hero .app-icon {
  width: 96px;
  height: 96px;
  border-radius: 22px;
  margin: 0 auto 1.5rem;
}

/* Link cards */
.link-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 2rem;
}

.link-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 1.25rem;
  text-decoration: none;
  color: var(--color-text);
  transition: border-color 0.15s, background 0.15s;
}

.link-card:hover {
  border-color: var(--color-accent);
  background: var(--color-surface-hover);
  text-decoration: none;
}

.link-card .card-icon {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.link-card .card-title {
  font-weight: 600;
  font-size: 0.9375rem;
  margin-bottom: 0.25rem;
}

.link-card .card-desc {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

/* Page content */
.page-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: -0.01em;
}

.page-meta {
  color: var(--color-text-secondary);
  font-size: 0.8125rem;
  margin-bottom: 2rem;
}

h2 {
  font-size: 1.125rem;
  font-weight: 700;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.375rem;
  border-bottom: 1px solid var(--color-border);
}

h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1rem;
}

ul,
ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

li {
  margin-bottom: 0.375rem;
}

/* Table */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.9375rem;
}

th,
td {
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
}

th {
  font-weight: 600;
  background: var(--color-surface);
  white-space: nowrap;
  width: 30%;
  color: var(--color-text-secondary);
}

/* Screenshot */
.screenshot-container {
  text-align: center;
  margin: 1.5rem 0 2rem;
}

.screenshot {
  max-width: 280px;
  width: 100%;
  border-radius: 16px;
  border: 1px solid var(--color-border);
}

/* FAQ */
.faq-item {
  margin-bottom: 1.5rem;
}

.faq-q {
  font-weight: 600;
  margin-bottom: 0.25rem;
  color: var(--color-warm);
}

.faq-a {
  color: var(--color-text-secondary);
}

/* Footer */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 1.5rem;
  text-align: center;
  font-size: 0.75rem;
  color: var(--color-text-secondary);
}

/* Mobile */
@media (max-width: 600px) {
  nav {
    gap: 0.75rem;
    font-size: 0.8125rem;
  }

  .link-cards {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

  table {
    font-size: 0.875rem;
  }

  th,
  td {
    padding: 0.5rem 0.75rem;
  }
}