/* ── Itsuki Portal – Static Pages ── */

:root {
  --bg: #faf8f8;
  --bg-card: #ffffff;
  --text: #2b2b2b;
  --text-muted: #6b7280;
  --accent: #284b63;
  --accent-hover: #1d3a4f;
  --border: #e5e5e5;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 10px 25px rgba(0, 0, 0, 0.08), 0 4px 10px rgba(0, 0, 0, 0.05);
  --radius: 12px;
  --font: "Source Sans Pro", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  --font-heading: "Schibsted Grotesk", "Hiragino Kaku Gothic ProN", sans-serif;
  --font-mono: "IBM Plex Mono", "Consolas", monospace;
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161618;
    --bg-card: #1e1e20;
    --text: #ebebec;
    --text-muted: #9ca3af;
    --accent: #7b97aa;
    --accent-hover: #9ab4c5;
    --border: #393639;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.2), 0 1px 2px rgba(0, 0, 0, 0.15);
    --shadow-hover: 0 10px 25px rgba(0, 0, 0, 0.3), 0 4px 10px rgba(0, 0, 0, 0.2);
  }
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* ── Header ── */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.header-inner {
  max-width: 960px;
  margin: 0 auto;
  padding: 0.8rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-title {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
}

.site-nav {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

.site-nav a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition);
}
.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--text);
}

/* ── Main ── */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  flex: 1;
}

/* ── Hero (Index) ── */
.hero {
  text-align: center;
  padding: 4rem 0 3rem;
}

.hero h1 {
  font-family: var(--font-heading);
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.75rem;
}

.hero p {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 480px;
  margin: 0 auto;
}

/* ── Section Cards ── */
.section-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 2.5rem;
}

.section-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  box-shadow: var(--shadow);
  transition: box-shadow var(--transition), transform var(--transition);
  text-decoration: none;
  color: inherit;
  display: block;
}

.section-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
  color: inherit;
}

.section-card .card-icon {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
  display: block;
}

.section-card h2 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
}

.section-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ── Page Content ── */
.page-content {
  max-width: 640px;
  margin: 0 auto;
  padding: 2rem 0;
}

.page-content h1 {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 1.5rem;
}

.page-content h2 {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.page-content p {
  margin-bottom: 1rem;
}

.page-content ul {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.page-content li {
  margin-bottom: 0.4rem;
}

.page-content code {
  font-family: var(--font-mono);
  background: var(--border);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.88em;
}

/* ── Footer ── */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ── Responsive ── */
@media (max-width: 600px) {
  .hero h1 {
    font-size: 1.75rem;
  }
  .hero {
    padding: 2.5rem 0 2rem;
  }
  .section-grid {
    grid-template-columns: 1fr;
  }
}