:root {
  --bg: #fbfaf7;
  --fg: #1f2328;
  --muted: #5f6670;
  --accent: #9a3b1f;
  --rule: #e2ddd3;
  --header-bg: #ffffff;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #17191c;
    --fg: #e6e4df;
    --muted: #a0a4aa;
    --accent: #e08a6a;
    --rule: #33363b;
    --header-bg: #1e2125;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.8;
}

.site-header {
  background: var(--header-bg);
  border-bottom: 1px solid var(--rule);
  padding: 1rem max(16px, calc((100% - 880px) / 2)) 0;
}
.site-name {
  display: block;
  color: var(--fg);
  text-decoration: none;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: .05em;
}
.site-name span {
  display: block;
  font-size: .8rem;
  font-weight: 400;
  color: var(--muted);
  letter-spacing: 0;
}
nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0 1.25rem;
  list-style: none;
  margin: .75rem 0 0;
  padding: 0;
}
nav a {
  display: block;
  padding: .4rem 0;
  color: var(--muted);
  text-decoration: none;
  font-size: .9rem;
  border-bottom: 2px solid transparent;
}
nav a:hover { color: var(--fg); }
nav a[aria-current="page"] { color: var(--accent); border-bottom-color: var(--accent); }

main {
  max-width: 880px;
  margin: 0 auto;
  padding: 2rem 16px 3rem;
  overflow-wrap: anywhere;
}
h1 { font-size: 1.75rem; margin: 0 0 1.25rem; }
h2 {
  font-size: 1.2rem;
  margin: 2.25rem 0 .75rem;
  padding-bottom: .3rem;
  border-bottom: 1px solid var(--rule);
}
a { color: var(--accent); }
ul { padding-left: 1.25rem; }
li { margin: .35rem 0; }
img { max-width: 100%; height: auto; border-radius: 6px; }

.articles li { font-size: .92rem; line-height: 1.7; margin: .7rem 0; }
.research img { display: block; max-width: 420px; width: 100%; margin: 1rem 0; }

footer {
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: .8rem;
  text-align: center;
  padding: 1.5rem 16px;
}
.pdf { margin: 1.5rem 0; }
.pdf object {
  display: block;
  width: 100%;
  aspect-ratio: 1 / 1.414;
  border: 1px solid var(--rule);
  border-radius: 6px;
}
.pdf figcaption { font-size: .85rem; margin-top: .3rem; }