:root{--bg:#f6f7fa;--card:#fff;--line:#e6e9f0;--ink:#14161c;--dim:#5b6070;--acc:#2f6fd0}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);
     font:16px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
.w{max-width:780px;margin:0 auto;padding:26px 18px 70px}
h1{font-size:24px;line-height:1.3;margin:0 0 16px}
h2{font-size:18px;margin:32px 0 10px;padding:9px 13px;background:#e9ecf5;border-radius:9px}
h3{font-size:16px;margin:24px 0 8px;color:#2b3a52}
h4{font-size:15px;margin:18px 0 6px;
h4{font-size:15px;margin:18px 0 6px;color:#3b455c}
p{margin:0 0 13px}
.tw{overflow-x:auto;margin:15px 0}
table{border-collapse:collapse;width:100%;background:var(--card);border-radius:10px;overflow:hidden;font-size:14.5px}
th,td{border-bottom:1px solid var(--line);padding:9px 11px;text-align:left;vertical-align:top}
th{background:#eef1f7;font-size:13px;color:var(--dim);font-weight:600;white-space:nowrap}
tr:last-child td{border-bottom:0}
blockquote{margin:15px 0;padding:11px 14px;background:#fff;border-left:4px solid #c8cede;
           border-radius:0 9px 9px 0;font-size:15px;color:#3b455c}
blockquote.need{background:#fff8e6;border-left-color:#f0a92b}
.tag{display:inline-block;background:#f0a92b;color:#fff;font-size:11px;font-weight:700;
     padding:2px 7px;border-radius:5px;margin-right:7px;vertical-align:1px;text-transform:uppercase;letter-spacing:.4px}
mark{background:#ffe08a;padding:1px 4px;border-radius:3px}
code{background:#eef1f7;padding:1px 5px;border-radius:4px;font:13.5px ui-monospace,Menlo,Consolas,monospace}
ul,ol{margin:0 0 13px;padding-left:22px}li{margin:5px 0}
hr{border:0;border-top:1px solid var(--line);margin:26px 0}
a{color:var(--acc);text-decoration:none}a:hover{text-decoration:underline}
.back{display:inline-block;margin-bottom:16px;font-size:14px;color:var(--dim)}
:target{animation:fl 2.2s ease-out}
@keyframes fl{0%,40%{background:#ffe9b0}100%{background:#fff8e6}}
@media print{.w{max-width:none;padding:0}.back{display:none}body{background:#fff;font-size:12pt}
 h2{background:none;padding:0;border-bottom:1px solid #999}}