:root{
  --bg:#f0f2f5;
  --panel:#ffffff;
  --border:#d9dee5;
  --primary:#2d5f96;
  --primary-dark:#1f4270;
  --text:#2b3440;
  --muted:#6b7684;
  --accent:#e68a2e;
  --ok:#2e8b57;
  --err:#b03a3a;
  --focus:rgba(45,95,150,.18);
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  font-family:"Segoe UI",system-ui,-apple-system,"Microsoft YaHei","PingFang SC",Roboto,Arial,sans-serif;
  background:var(--bg);color:var(--text);line-height:1.55;font-size:15px;
  display:flex;flex-direction:column;min-height:100vh;
}
.wrap{flex:1;width:100%;max-width:920px;margin:0 auto;padding:20px 18px 40px}

/* ===== Top menu bar ===== */
.menubar{
  background:linear-gradient(180deg,#3a6ea5,#2d5f96);
  color:#fff;box-shadow:0 1px 3px rgba(0,0,0,.25);
  position:sticky;top:0;z-index:50;
}
.menubar-inner{width:100%;max-width:1120px;margin:0 auto;padding:0 12px;
  display:flex;align-items:center;gap:8px;flex-wrap:wrap;min-height:46px}
.brand{font-weight:600;font-size:15px;padding:0 6px;display:flex;align-items:center;gap:8px;white-space:nowrap}
.brand .logo{
  width:24px;height:24px;flex:0 0 24px;border-radius:4px;background:#fff;
  display:inline-flex;align-items:center;justify-content:center;color:var(--primary-dark);font-weight:700;font-size:13px;
}
.menu-spacer{flex:1}
.menu-links{display:flex;align-items:center;gap:2px;flex-wrap:wrap}
.menubar a.btn{
  color:#fff;text-decoration:none;font-size:13.5px;padding:6px 12px;border-radius:4px;
  display:inline-flex;align-items:center;gap:6px;border:1px solid transparent;
}
.menubar a.btn:hover{background:rgba(255,255,255,.14);border-color:rgba(255,255,255,.35)}
.menubar a.btn.active{background:#fff;color:var(--primary-dark);font-weight:600}

/* ===== Grouped dropdown (Windows menu-bar style) ===== */
.menubar .mgroup{position:relative;display:inline-block}
.menubar button.mgtop{
  color:#fff;background:transparent;border:1px solid transparent;border-radius:4px;
  font-family:inherit;font-size:13px;padding:6px 9px;cursor:pointer;white-space:nowrap;
  display:inline-flex;align-items:center;gap:5px;
}
.menubar button.mgtop::after{content:"\25be";font-size:8px;line-height:1;opacity:.8;margin-top:1px}
.menubar button.mgtop:hover{background:rgba(255,255,255,.14);border-color:rgba(255,255,255,.35)}
.menubar button.mgtop.on{background:#fff;color:var(--primary-dark);font-weight:600}
.menubar .mgmenu{
  display:none;position:absolute;left:0;top:calc(100% + 2px);min-width:238px;
  background:#fff;color:var(--text);border:1px solid var(--border);border-radius:6px;
  box-shadow:0 10px 26px rgba(0,0,0,.22);padding:5px;z-index:120;
}
.menubar .mgroup.open .mgmenu{display:block;animation:mgpop .12s ease}
@keyframes mgpop{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:none}}
.menubar .mgmenu a.btn{
  display:block;width:100%;color:var(--text);font-size:13.5px;padding:7px 12px;border-radius:4px;
  border:1px solid transparent;white-space:nowrap;
}
.menubar .mgmenu a.btn:hover{background:#eef3f9;border-color:transparent;color:var(--primary-dark)}
.menubar .mgmenu a.btn.active{background:#e3edf7;color:var(--primary);font-weight:600}
/* keep the right-most dropdowns inside the viewport */
.menubar .mgroup:nth-last-child(-n+3) .mgmenu{left:auto;right:0}
.menubar button.mgtop:focus-visible{outline:2px solid #fff;outline-offset:1px}
.menubar .mgmenu a.btn:focus-visible{outline:2px solid var(--primary);outline-offset:-2px}
.langsel{position:relative;display:inline-block}
.langbtn{
  color:#fff;background:rgba(255,255,255,.10);border:1px solid rgba(255,255,255,.35);
  padding:6px 12px;border-radius:4px;cursor:pointer;font-size:13.5px;display:inline-flex;align-items:center;gap:6px;
}
.langbtn:hover{background:rgba(255,255,255,.2)}
.langmenu{
  display:none;position:absolute;right:0;top:calc(100% + 4px);background:#fff;color:var(--text);
  border-radius:6px;box-shadow:0 4px 16px rgba(0,0,0,.18);min-width:200px;overflow:hidden;z-index:100;
}
.langmenu.open{display:block}
.langmenu button{
  display:block;width:100%;padding:9px 14px;border:none;background:none;text-align:left;cursor:pointer;font-size:14px;
}
.langmenu button:hover{background:#eef3f9}
.langmenu button.cur{background:#e3edf7;color:var(--primary);font-weight:600}

/* ===== Panels ===== */
.card{
  background:var(--panel);border:1px solid var(--border);border-radius:8px;
  box-shadow:0 1px 3px rgba(0,0,0,.06);margin-bottom:18px;overflow:hidden;
}
.card .hd{
  padding:13px 18px;border-bottom:1px solid var(--border);background:#fafbfd;
  display:flex;align-items:center;gap:10px;
}
.card .hd h2{font-size:16.5px;font-weight:600}
.card .hd .badge{
  font-size:11px;background:var(--primary);color:#fff;border-radius:3px;padding:2px 8px;letter-spacing:.3px;
}
.card .bd{padding:18px}
.tabs{display:flex;gap:0;padding:0 10px;background:var(--panel);border-bottom:1px solid var(--border)}
.tabs a{
  padding:11px 18px;text-decoration:none;color:var(--muted);font-size:14px;border-bottom:2px solid transparent;font-weight:500;
}
.tabs a:hover{color:var(--text)}
.tabs a.on{color:var(--primary);border-bottom-color:var(--primary);font-weight:600}

h1.title{font-size:22px;margin:6px 0 4px}
.sub{color:var(--muted);font-size:13.5px;margin-bottom:18px}

.field{margin-bottom:16px}
.field label{display:block;font-size:13.5px;font-weight:600;margin-bottom:6px}
.field .hint{font-size:12.5px;color:var(--muted);font-weight:400;margin-top:3px}
.control{display:flex;gap:8px;align-items:center}
.pick{position:relative;flex:0 0 auto}
.pick select{
  appearance:none;-webkit-appearance:none;padding:8px 30px 8px 12px;border:1px solid var(--border);
  border-radius:6px;background:#fff url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%236b7684'/%3E%3C/svg%3E") no-repeat right 12px center;
  font-size:14px;cursor:pointer;min-width:150px;
}
.pick select:focus,.in:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--focus)}
.in{
  width:100%;padding:9px 12px;border:1px solid var(--border);border-radius:6px;font-size:15px;background:#fff;
}
.in:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--focus)}
.in.err{border-color:var(--err)}
.unit-inline{font-size:14px;color:var(--muted);margin-left:8px}
ul.ref-list{list-style:none;margin:0;padding:0}
ul.ref-list li{padding:8px 0;padding-left:18px;position:relative;font-size:14px;color:var(--text);border-bottom:1px dashed var(--border)}
ul.ref-list li:last-child{border-bottom:none}
ul.ref-list li::before{content:"\25B8";position:absolute;left:0;top:9px;color:var(--primary);font-size:11px}

button.calc{
  background:linear-gradient(180deg,#3a6ea5,#2d5f96);color:#fff;border:none;border-radius:6px;
  padding:11px 20px;font-size:15px;font-weight:600;cursor:pointer;box-shadow:0 1px 2px rgba(0,0,0,.18);
}
button.calc:hover{filter:brightness(1.06)}
button.ghost{
  background:#fff;border:1px solid var(--border);border-radius:6px;padding:10px 16px;font-size:14px;cursor:pointer;color:var(--text);
}
button.ghost:hover{border-color:var(--primary);color:var(--primary)}
.actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:6px}

/* result */
.result{
  border:1px solid var(--border);border-radius:8px;padding:16px 18px;margin-top:18px;background:#fbfcfe;
  display:none;
}
.result.show{display:block;animation:pop .18s ease}
@keyframes pop{from{opacity:0;transform:translateY(-3px)}to{opacity:1}}
.result .rhead{font-size:13px;color:var(--muted);margin-bottom:6px;font-weight:600;letter-spacing:.3px}
.result .big{font-size:22px;font-weight:700;color:var(--primary);margin:2px 0}
.result .prop{display:flex;justify-content:space-between;gap:12px;padding:7px 0;border-top:1px dashed var(--border);font-size:14px}
.result .prop:first-of-type{border-top:none}
.result .prop .k{color:var(--muted)}
.result .prop .v{font-weight:600;text-align:right}
.result .note{margin-top:10px;font-size:12.5px;color:var(--muted);border-left:3px solid var(--primary);padding:4px 10px;background:#f2f6fb;border-radius:0 4px 4px 0}
.result.bad .big{color:var(--err)}
.result .chip{display:inline-block;font-size:12px;padding:2px 9px;border-radius:20px;font-weight:600}
.chip.ok{background:#eaf6ef;color:var(--ok)}
.chip.warn{background:#fdf1e3;color:var(--accent)}
.chip.err{background:#fbeaea;color:var(--err)}

/* table */
table.grid{width:100%;border-collapse:collapse;font-size:13.5px}
table.grid th{background:var(--primary);color:#fff;padding:8px 10px;text-align:left;font-weight:600}
table.grid td{padding:8px 10px;border-bottom:1px solid var(--border)}
table.grid tr:nth-child(even){background:#f7f9fc}
table.grid td.dim{color:var(--muted)}

/* disclaimer */
.disclaimer{
  background:#fff7ed;border:1px solid #f2d7b0;border-radius:8px;padding:14px 18px;margin-top:6px;font-size:12.5px;color:#6b4a1f;
}
.disclaimer b{display:block;margin-bottom:4px;font-size:13px}
.disclaimer a{color:var(--accent)}

footer{background:#2a3440;color:#c6ccd4;padding:16px;text-align:center;font-size:12.5px;margin-top:auto}
footer a{color:#9fc2e8;text-decoration:none}
.kgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:12px}
@media(max-width:560px){
  .menubar-inner{min-height:auto;padding:8px}
  .menubar button.mgtop{font-size:12.5px;padding:5px 7px}
  .menubar .mgmenu{left:auto;right:0;min-width:200px}
}

/* packed-product storage table */
.vtable{border:1px solid var(--border);border-radius:8px;overflow:hidden;margin-top:4px}
.vrow{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid var(--border)}
.vrow:first-child{border-top:none}
.vrow:has(.vc2){grid-template-columns:1fr 2fr}
.vc,.vc2{padding:10px 12px;font-size:13.5px}
.vc.vh{background:var(--primary);color:#fff;font-weight:600}
.vc.vk{color:var(--muted);font-weight:600}
.vc{border-left:1px solid var(--border)}
.vc:first-child{border-left:none}
.vc2{border-top:1px solid var(--border);color:var(--text)}
.vrow:not(:first-child){border-top:1px solid var(--border)}
ul.hints{margin:10px 0 4px;padding-left:18px;font-size:12.5px;color:var(--muted)}
ul.hints li{margin:3px 0}