/* S2「素白 · 石青」— 冷静克制（无衬线为主，石青点缀） */
:root{
  --bg:#f7f8f7; --card:#ffffff; --fg:#26302e; --tx:#131c1b;
  --mut:#52605d; --line:rgba(38,48,46,.12); --line-2:rgba(38,48,46,.24);
  --hover:rgba(38,48,46,.045);
  --acc:#1f5f5b; --acc2:#3f7d6a;
  --footbg:#152220; --footfg:#c3d0cd; --footmut:#82948f;
  --sans:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,monospace;
  --fhead:"Songti SC","STSong","Noto Serif SC","SimSun",Georgia,serif;
  --fbody:var(--sans);
  --fs:17.5px; --lh:1.95; --wrap:1080px; --radius:10px;
}
html[data-night]{
  --bg:#101615; --card:#18211f; --fg:#c6d2ce; --tx:#e6eeeb;
  --mut:#9fb1ac; --line:rgba(198,210,206,.14); --line-2:rgba(198,210,206,.3);
  --hover:rgba(198,210,206,.07);
  --acc:#5fbdb2; --acc2:#7ec6a6;
  --footbg:#080d0c; --footfg:#9fb0ab; --footmut:#6d7d78;
}
.seal{border-radius:9px}
.masthead h1,.sec-t h2,.tl-x,.tcard .tsay{letter-spacing:.01em}