:root{
  --brand:#2f5cff; --brand2:#7a5cff; --ink:#1a1d24; --sub:#5b6270; --line:#e6e8ee;
  --bg:#f7f8fa; --card:#fff; --good:#12b76a; --warn:#f79009; --bad:#f04438;
  --blue:#eef2ff; --soft:#f3f5f9;
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;line-height:1.75;font-size:15px;}
.topbar{background:#fff;border-bottom:1px solid var(--line);padding:14px 24px;}
.topbar .inner{max-width:860px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;}
.logo{font-weight:800;font-size:18px;color:var(--brand);text-decoration:none;}
.logo span{color:var(--ink);font-weight:600;}
.logo a{color:inherit;text-decoration:none;}
.wrap{max-width:860px;margin:0 auto;padding:28px 20px 80px;}
h1{font-size:26px;line-height:1.4;margin:8px 0 6px;font-weight:800;}
.subtitle{color:var(--sub);font-size:15px;margin:0 0 6px;}
.diff{display:inline-block;background:var(--blue);color:var(--brand);border-radius:8px;padding:3px 12px;font-size:13px;font-weight:600;margin:4px 6px 4px 0;}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:22px;margin:18px 0;box-shadow:0 1px 3px rgba(20,30,60,.04);}
.tabs{display:flex;gap:8px;margin-bottom:18px;flex-wrap:wrap;}
.tab{flex:1;min-width:150px;text-align:center;padding:12px;border-radius:10px;border:1px solid var(--line);background:var(--soft);cursor:pointer;font-weight:600;color:var(--sub);transition:.15s;}
.tab.active{background:var(--brand);color:#fff;border-color:var(--brand);}
.field{margin:14px 0;}
.field label{display:block;font-size:14px;font-weight:600;color:#333a47;margin-bottom:6px;}
.field input[type=number],.field select{width:100%;padding:11px 12px;border:1px solid var(--line);border-radius:10px;font-size:15px;color:var(--ink);background:#fff;}
.field input:focus,.field select:focus{outline:none;border-color:var(--brand);}
.hint{font-size:12px;color:var(--sub);margin-top:4px;}
.chkrow{display:flex;flex-wrap:wrap;gap:10px;align-items:center;}
.chk{display:flex;align-items:center;gap:6px;font-size:14px;padding:8px 12px;border:1px solid var(--line);border-radius:10px;cursor:pointer;}
.chk input{width:16px;height:16px;accent-color:var(--brand);}
.result{background:linear-gradient(135deg,#eef2ff,#f7f2ff);border:1px solid #e3e8ff;border-radius:12px;padding:18px;margin-top:16px;}
.result .row{display:flex;justify-content:space-between;padding:8px 0;border-bottom:1px dashed #dfe4ff;font-size:14px;}
.result .row:last-child{border-bottom:none;}
.result .row .v{font-weight:700;}
.result .big{font-size:22px;font-weight:800;color:var(--brand);}
.result .net{color:var(--good);font-size:22px;font-weight:800;}
.note{font-size:12px;color:var(--sub);margin-top:10px;line-height:1.6;}
h2{font-size:20px;margin:40px 0 12px;font-weight:800;padding-left:12px;border-left:4px solid var(--brand);}
h3{font-size:16px;margin:24px 0 10px;font-weight:700;}
p{margin:10px 0;color:#2a2f3a;}
table{width:100%;border-collapse:collapse;font-size:14px;margin:12px 0;}
th,td{border:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:top;}
th{background:var(--soft);font-weight:700;color:#333a47;}
tr:nth-child(even) td{background:#fafbfd;}
.callout{border-radius:12px;padding:14px 16px;margin:16px 0;border:1px solid;font-size:14px;}
.callout.tip{background:#f0fbf6;border-color:#c8f0dd;}
.callout.tip b{color:var(--good);}
.callout.warn{background:#fff8ec;border-color:#fbe3bf;}
.callout.warn b{color:var(--warn);}
.callout.info{background:#f1f5ff;border-color:#d6e1ff;}
.callout.info b{color:var(--brand);}
.foot{margin-top:40px;padding-top:20px;border-top:1px solid var(--line);font-size:12px;color:var(--sub);line-height:1.7;}
.nav{margin:8px 0 0;font-size:13px;color:var(--sub);}
.nav a{color:var(--brand);text-decoration:none;margin-right:10px;}
@media(max-width:600px){h1{font-size:22px;}.tab{min-width:120px;}}