:root {
  --paper: #FAFAF7;
  --surface: #FFFFFF;
  --ink: #1A1D1A;
  --muted: rgba(26, 29, 26, 0.62);
  --rule: rgba(26, 29, 26, 0.14);
  --accent: #E8590C;
  --todo-bg: #fff1c2;
  --todo-ink: #6b4b00;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #131311;
    --surface: #1E1E1B;
    --ink: #F2F2EC;
    --muted: rgba(242, 242, 236, 0.62);
    --rule: rgba(242, 242, 236, 0.14);
    --accent: #FF6B1A;
    --todo-bg: #4a3a0c;
    --todo-ink: #ffe29a;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #131311;
  --surface: #1E1E1B;
  --ink: #F2F2EC;
  --muted: rgba(242, 242, 236, 0.62);
  --rule: rgba(242, 242, 236, 0.14);
  --accent: #FF6B1A;
  --todo-bg: #4a3a0c;
  --todo-ink: #ffe29a;
  color-scheme: dark;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  font-size: 16px;
  line-height: 1.9;
  padding-inline: 20px;
}
.page { max-width: 42rem; margin-inline: auto; padding-block: 40px 72px; }

.masthead { display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between; gap: 8px 24px; padding-bottom: 16px; border-bottom: 1px solid var(--rule); }
.brand { font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif; font-weight: 700; font-size: 1.05rem; color: var(--ink); text-decoration: none; letter-spacing: 0.04em; }
.masthead nav { display: flex; gap: 20px; font-size: 0.9rem; }
.masthead nav a { color: var(--muted); text-decoration: none; }
.masthead nav a[aria-current="page"] { color: var(--accent); font-weight: 700; }
.masthead nav a:hover, .masthead nav a:focus-visible { color: var(--accent); }

h1 { font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif; font-size: 1.9rem; line-height: 1.4; margin: 40px 0 8px; text-wrap: balance; }
.dates { color: var(--muted); font-size: 0.85rem; margin: 0 0 24px; font-variant-numeric: tabular-nums; }
.lead { margin: 0 0 32px; }

section { padding-block: 20px; border-top: 1px solid var(--rule); }
h2 { font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif; font-size: 1.15rem; line-height: 1.5; margin: 0 0 8px; display: flex; gap: 12px; text-wrap: balance; }
h2 .no { color: var(--accent); flex: none; font-variant-numeric: tabular-nums; }
p { margin: 0 0 12px; }
ol, ul { margin: 0 0 12px; padding-left: 1.5em; }
li { margin-bottom: 4px; }

.table-wrap { overflow-x: auto; margin: 8px 0 16px; }
table { border-collapse: collapse; width: 100%; font-size: 0.92rem; line-height: 1.7; }
th, td { text-align: left; vertical-align: top; padding: 10px 12px; border-bottom: 1px solid var(--rule); }
th { font-weight: 700; color: var(--muted); font-size: 0.82rem; letter-spacing: 0.04em; white-space: nowrap; }
td:first-child { white-space: nowrap; font-weight: 700; }

main a, footer a { color: var(--ink); text-decoration-color: var(--accent); text-decoration-thickness: 1.5px; text-underline-offset: 3px; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }
.todo { background: var(--todo-bg); color: var(--todo-ink); padding: 0 4px; border-radius: 3px; font-weight: 700; }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); gap: 12px; margin: 24px 0; }
.card { background: var(--surface); border: 1px solid var(--rule); border-radius: 16px; padding: 16px 18px; color: var(--ink); text-decoration: none; display: flex; flex-direction: column; gap: 4px; }
.card strong { font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif; color: var(--accent); }
.card span { color: var(--muted); font-size: 0.9rem; line-height: 1.6; }
.card:hover, .card:focus-visible { border-color: var(--accent); }

footer { margin-top: 48px; color: var(--muted); font-size: 0.82rem; }