/* Layout: one readable column; each example mail sits on its own sheet. */
:root {
  --bg: #f4f6f8; --paper: #ffffff; --ink: #1d2733; --muted: #5f6d7b; --line: #d9e0e7;
  --accent: #3b6ea8; --on-accent: #ffffff; --mark: #fff1b8; --mark-ink: #7a5a00; --band: #d9ecf7;
  --font: "Hiragino Sans", "Yu Gothic UI", "Yu Gothic", "Meiryo", sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11151a; --paper: #1a2027; --ink: #e3e9ef; --muted: #9aa7b5; --line: #2c3540;
    --accent: #7fb0e6; --on-accent: #11151a; --mark: #4a3d12; --mark-ink: #ffe08a; --band: #1d2d3a;
    color-scheme: dark;
  }
}
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.8 var(--font); }
a { color: var(--accent); }
a:focus-visible, button:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
.top, main, .foot {
  max-width: 720px; margin: 0 auto; box-sizing: border-box;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
}
.top { display: flex; justify-content: space-between; align-items: center; padding-block: 12px; font-size: 14px; }
.brand { font-weight: 700; text-decoration: none; }
main { display: flex; flex-direction: column; gap: 22px; padding-block: 8px 32px; }
main > * { margin-block: 0; min-width: 0; }
.crumb { font-size: 12px; color: var(--muted); }
h1 { font-size: clamp(25px, 6vw, 34px); line-height: 1.35; text-wrap: balance; word-break: auto-phrase; margin-top: -14px; }
h2 { font-size: 19px; line-height: 1.45; margin: 0 0 10px; text-wrap: balance; }
.lead { margin-top: -8px; }
.cta {
  display: block; text-align: center; font-weight: 700; text-decoration: none;
  background: var(--accent); color: var(--on-accent); border-radius: 10px; padding: 13px 16px;
}
.toc { margin: 0; padding-left: 1.4em; font-size: 15px; }
.mail { background: var(--paper); border: 1px solid var(--line); border-radius: 12px; padding: 16px; scroll-margin-top: 12px; }
.sub { display: flex; flex-direction: column; margin: 0 0 12px; padding-bottom: 10px; border-bottom: 1px dashed var(--line); font-weight: 700; font-size: 15px; overflow-wrap: anywhere; }
.sub > span:first-child { font: 400 11px/1.5 var(--font); color: var(--muted); }
pre { margin: 0; font: 14.5px/1.85 var(--font); white-space: pre-wrap; overflow-wrap: anywhere; }
mark { background: var(--mark); color: var(--mark-ink); border-radius: 3px; }
.row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
button {
  flex: 1 1 130px; border: 1px solid var(--line); border-radius: 999px; padding: 9px 14px; cursor: pointer;
  background: var(--paper); color: var(--ink); font: 700 13px var(--font);
}
.tips { margin: 0; }
.tips dt { font-weight: 700; margin-top: 12px; }
.tips dt:first-child { margin-top: 0; }
.tips dd { margin: 0; }
.band { background: var(--band); border-radius: 12px; padding: 16px; }
.band p { margin: 0 0 12px; font-size: 15px; }
.links { margin: 0; padding-left: 1.2em; }
.foot { padding-block: 16px 28px; border-top: 1px solid var(--line); font-size: 12px; color: var(--muted); }
.foot p { margin: 4px 0; }