:root {
  --bg: #0f1419;
  --bg-elevated: #1a222c;
  --text: #e8eef4;
  --muted: #8a9aab;
  --accent: #3d9cf0;
  --line: #2a3542;
  --font-sans: "IBM Plex Sans", "Hiragino Sans", "Noto Sans JP", sans-serif;
  --font-display: "IBM Plex Sans", "Hiragino Sans", "Noto Sans JP", sans-serif;
  --max: 68rem;
  --space: clamp(1rem, 3vw, 2rem);
}

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

html {
  color-scheme: dark;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text);
  background:
    radial-gradient(120% 80% at 10% -10%, #1e3a55 0%, transparent 55%),
    radial-gradient(90% 60% at 100% 0%, #163028 0%, transparent 45%),
    var(--bg);
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  color: #7eb8f5;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--space);
  border-bottom: 1px solid var(--line);
}

.brand {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.15rem;
  letter-spacing: 0.02em;
  color: var(--text);
  text-decoration: none;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  font-size: 0.95rem;
}

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

.nav a:hover,
.nav a[aria-current="page"] {
  color: var(--text);
}

main {
  max-width: var(--max);
  margin: 0 auto;
  padding: calc(var(--space) * 2) var(--space);
}

.hero {
  min-height: 55vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1rem;
  padding-bottom: 3rem;
}

.hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 6vw, 3.75rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.lead {
  margin: 0;
  max-width: 36rem;
  color: var(--muted);
  font-size: 1.1rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.2rem;
  border-radius: 0.35rem;
  border: 1px solid transparent;
  font: inherit;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
}

.btn-primary {
  background: var(--accent);
  color: #061018;
}

.btn-primary:hover {
  background: #6eb0f5;
  color: #061018;
}

.btn-ghost {
  border-color: var(--line);
  color: var(--text);
  background: transparent;
}

.btn-ghost:hover {
  border-color: var(--muted);
  color: var(--text);
}

.section {
  padding: 2.5rem 0;
  border-top: 1px solid var(--line);
}

.section h2 {
  margin: 0 0 0.75rem;
  font-size: 1.5rem;
  font-weight: 600;
}

.placeholder {
  margin: 0;
  padding: 1.25rem;
  color: var(--muted);
  background: var(--bg-elevated);
  border: 1px dashed var(--line);
  border-radius: 0.4rem;
}

.page-title {
  margin: 0 0 0.5rem;
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 600;
}

.page-lead {
  margin: 0 0 2rem;
  color: var(--muted);
}

.site-footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--space);
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  margin-bottom: 0.75rem;
}

.site-footer a {
  color: var(--muted);
  text-decoration: none;
}

.site-footer a:hover {
  color: var(--text);
}