:root {
  --bg: #f6f7f8;
  --surface: #ffffff;
  --text: #101214;
  --muted: #606975;
  --line: #dfe3e8;
  --accent: #0d3b66;
  --accent-soft: #e8eff6;
  --max: 980px;
  --radius: 14px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, #fafbfc 0%, var(--bg) 60%);
}

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

.page {
  width: min(100% - 32px, var(--max));
  margin: 0 auto;
  padding: 32px 0 72px;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 28px;
}

.brand {
  font-size: 14px;
  letter-spacing: 0.06em;
  color: var(--muted);
  text-transform: uppercase;
}

.lang-switch {
  display: inline-flex;
  border: 1px solid var(--line);
  border-radius: 999px;
  overflow: hidden;
  background: var(--surface);
}

.lang-switch a {
  padding: 8px 14px;
  font-size: 13px;
  color: var(--muted);
}

.lang-switch a.active {
  background: var(--accent);
  color: #fff;
}

.hero {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
  margin-bottom: 20px;
}

h1 {
  margin: 0 0 8px;
  font-size: clamp(30px, 5vw, 46px);
  line-height: 1.1;
}

.lead {
  margin: 0;
  font-size: clamp(16px, 2.2vw, 20px);
  color: #28313d;
  max-width: 820px;
}

.grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 20px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
}

h2 {
  margin: 0 0 12px;
  font-size: 18px;
}

h3 {
  margin: 14px 0 8px;
  font-size: 15px;
  color: #253241;
}

.books-layout {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 8px;
}

.book-group {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px;
  background: #fbfcfd;
}

.book-group h3 {
  margin: 0 0 10px;
}

.book-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.book-list li {
  margin: 0 0 8px;
  padding: 8px 10px;
  border-radius: 9px;
  background: #fff;
  border: 1px solid #e6eaef;
  line-height: 1.45;
}

.book-list li:last-child {
  margin-bottom: 0;
}

p { margin: 0 0 12px; line-height: 1.7; }

ul {
  margin: 0;
  padding-left: 18px;
}

li { margin: 0 0 10px; line-height: 1.6; }

.kicker {
  display: inline-block;
  margin-bottom: 10px;
  padding: 4px 8px;
  border-radius: 8px;
  font-size: 12px;
  background: var(--accent-soft);
  color: #1f3f5e;
}

.timeline li strong,
.projects li strong {
  display: block;
  font-weight: 700;
  margin-bottom: 2px;
}

.links li { margin-bottom: 8px; }

.footer {
  margin-top: 20px;
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 900px) {
  .grid {
    grid-template-columns: 1fr;
  }

  .books-layout {
    grid-template-columns: 1fr;
  }
}