:root {
  --bg: #F3EEE3; --card: #FBF8F1; --ink: #1A1814; --dim: #6B655B;
  --you: #F0461E; --index: #2643D9; --line: #DDD5C5;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #1A1814; --card: #24211C; --ink: #F3EEE3; --dim: #A8A196;
    --you: #FF6A44; --index: #7D93FF; --line: #3A352D;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: "Zen Kaku Gothic New", -apple-system, "Hiragino Sans", sans-serif;
  line-height: 1.85; font-size: 16px;
}
main { max-width: 680px; margin: 0 auto; padding: 40px 16px 64px; }
.app { display: flex; align-items: center; gap: 14px; margin-bottom: 28px; }
.app img { width: 56px; height: 56px; border-radius: 13px; }
.app b { font-size: 20px; display: block; line-height: 1.3; }
.app span { color: var(--dim); font-size: 13px; }
h1 { font-size: 26px; line-height: 1.4; margin: 0 0 6px; }
.date { color: var(--dim); font-size: 13px; margin: 0 0 28px; }
h2 { font-size: 17px; margin: 32px 0 6px; padding-left: 12px; border-left: 4px solid var(--you); line-height: 1.5; }
p, li { margin: 6px 0; }
ul { padding-left: 1.3em; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 16px 18px; margin: 16px 0; }
.mail { font-size: 18px; font-weight: 700; word-break: break-all; }
a { color: var(--index); }
footer { margin-top: 48px; color: var(--dim); font-size: 13px; border-top: 1px solid var(--line); padding-top: 16px; }