/* ========== Base (Light) ========== */
:root {
  --bg: #ffffff;
  --panel: #ffffff;
  --text: #0f172a;      /* slate-900 */
  --muted: #475569;     /* slate-600 */
  --line: rgba(15, 23, 42, 0.12);
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
  --radius: 16px;
  --max: 980px;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans JP", "Yu Gothic", "Meiryo", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
}

a { color: inherit; text-decoration: none; }
a:hover { text-decoration: underline; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; }
.container { width: min(var(--max), calc(100% - 32px)); margin: 0 auto; }

/* Skip link */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 12px;
  background: #0f172a;
  color: #ffffff;
  padding: 10px 12px;
  border-radius: 10px;
  z-index: 9999;
}
.skip-link:focus { left: 12px; }

/* ========== Header ========== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  gap: 16px;
  align-items: center;
  justify-content: flex-start;
  padding: 14px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
}

.brand-logo {
  width: 150px;
  height: auto;
  display: block;
}

/* ========== Main ========== */
.hero { padding: 34px 0 14px; }
h1 {
  margin: 0 0 10px;
  font-size: clamp(24px, 3.2vw, 36px);
  letter-spacing: 0.02em;
}
.lead {
  margin: 0;
  color: var(--muted);
  max-width: 70ch;
}
.meta {
  margin-top: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  color: var(--muted);
  font-size: 13px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px 18px;
  margin: 16px 0;
}

.card h2 {
  margin: 0 0 10px;
  font-size: 18px;
}
.card p { margin: 10px 0; }
.card ul {
  margin: 10px 0 0;
  padding-left: 1.1em;
}
.card li { margin: 6px 0; }

/* Footer */
.site-footer { padding: 24px 0 40px; }
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  color: var(--muted);
  border-top: 1px solid var(--line);
  padding-top: 16px;
}
.to-top {
  color: var(--muted);
  border: 1px solid var(--line);
  padding: 8px 10px;
  border-radius: 999px;
}
.to-top:hover {
  background: rgba(15, 23, 42, 0.04);
  text-decoration: none;
}

/* ========== Responsive ========== */
@media (max-width: 720px) {
  .brand-logo { width: 140px; }
}

/* ========== Print ========== */
@media print {
  body { background: #fff; color: #000; }
  .site-header { position: static; background: #fff; backdrop-filter: none; }
  .card { box-shadow: none; }
  .to-top, .skip-link { display: none !important; }
}