:root{
  --bg:#0f1115; --panel:#171a21; --panel2:#1e222b; --line:#2a2f3a;
  --text:#e8eaed; --muted:#9aa3b2; --brand:#4f8cff; --brand2:#3a6fd6;
  --ok:#28c76f; --warn:#ff9f43; --err:#ea5455; --gold:#d4af37;
  --radius:12px; --shadow:0 6px 24px rgba(0,0,0,.35);
}
*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg);color:var(--text);font-size:15px;-webkit-font-smoothing:antialiased}
a{color:var(--brand);text-decoration:none}
.muted{color:var(--muted)} .small{font-size:12.5px} .right{text-align:right} .center{text-align:center}
.mono{font-variant-numeric:tabular-nums;font-feature-settings:"tnum"}
h1,h2,h3{margin:0 0 .4em}

/* buttons */
.btn{cursor:pointer;border:1px solid var(--line);background:var(--panel2);color:var(--text);
  padding:9px 14px;border-radius:10px;font-size:14px;font-weight:600;transition:.15s;white-space:nowrap}
.btn:hover{border-color:#3a4150;background:#232834}
.btn.primary{background:var(--brand);border-color:var(--brand);color:#fff}
.btn.primary:hover{background:var(--brand2)}
.btn.ok{background:var(--ok);border-color:var(--ok);color:#06281a}
.btn.danger{background:transparent;border-color:var(--err);color:var(--err)}
.btn.ghost{background:transparent}
.btn.sm{padding:5px 10px;font-size:12.5px;border-radius:8px}
.btn.lg{padding:14px 22px;font-size:17px;border-radius:12px}
.btn:disabled{opacity:.5;cursor:not-allowed}

/* inputs */
input,select,textarea{font:inherit;color:var(--text);background:var(--panel);border:1px solid var(--line);
  border-radius:9px;padding:9px 11px;width:100%}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--brand)}
label{display:block;font-size:13px;color:var(--muted);margin-bottom:10px}
label input,label select{margin-top:5px}

/* layout */
.app{display:grid;grid-template-columns:220px 1fr;min-height:100vh}
.sidebar{background:var(--panel);border-right:1px solid var(--line);padding:16px 12px;display:flex;flex-direction:column;gap:4px}
.sb-brand{font-weight:800;font-size:18px;padding:8px 10px 16px;letter-spacing:.5px}
.nav{display:flex;flex-direction:column;gap:2px;flex:1}
.nav a{display:flex;align-items:center;gap:10px;padding:10px 12px;border-radius:9px;color:var(--muted);font-weight:600;font-size:14px}
.nav a:hover{background:var(--panel2);color:var(--text)}
.nav a.active{background:var(--brand);color:#fff}
.nav .ico{width:20px;text-align:center}
.main{display:flex;flex-direction:column;min-width:0}
.topbar{display:flex;align-items:center;justify-content:space-between;padding:14px 22px;border-bottom:1px solid var(--line);background:var(--panel)}
.tb-title{font-size:18px;font-weight:700}
.tb-right{display:flex;align-items:center;gap:12px}
.content{padding:22px;overflow:auto}

/* cards / stats */
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.grid{display:grid;gap:14px}
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:14px;margin-bottom:18px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:16px}
.stat .k{color:var(--muted);font-size:13px;margin-bottom:6px}
.stat .v{font-size:26px;font-weight:800;letter-spacing:.5px}
.stat .v.ok{color:var(--ok)} .stat .v.warn{color:var(--warn)} .stat .v.gold{color:var(--gold)}

/* tables */
.toolbar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-bottom:14px}
.toolbar .grow{flex:1}
table{width:100%;border-collapse:collapse;font-size:13.5px}
thead th{position:sticky;top:0;background:var(--panel2);text-align:left;padding:10px;color:var(--muted);
  font-weight:600;border-bottom:1px solid var(--line);white-space:nowrap}
tbody td{padding:10px;border-bottom:1px solid var(--line)}
tbody tr:hover{background:var(--panel2)}
.tablewrap{max-height:calc(100vh - 280px);overflow:auto;border:1px solid var(--line);border-radius:var(--radius)}
.tag{display:inline-block;padding:2px 9px;border-radius:999px;font-size:11.5px;font-weight:700}
.tag.ok{background:rgba(40,199,111,.15);color:var(--ok)}
.tag.warn{background:rgba(255,159,67,.15);color:var(--warn)}
.tag.err{background:rgba(234,84,85,.15);color:var(--err)}
.tag.muted{background:var(--panel2);color:var(--muted)}
.badge{padding:3px 9px;border-radius:999px;font-size:11.5px;font-weight:700;background:var(--panel2)}
.badge.admin{background:rgba(212,175,55,.18);color:var(--gold)}
.badge.purchaser{background:rgba(79,140,255,.18);color:var(--brand)}
.badge.cashier{background:rgba(40,199,111,.18);color:var(--ok)}

/* gate / login */
.gate{display:flex;align-items:center;justify-content:center;min-height:100vh;padding:20px}
.login{width:360px;max-width:100%}
.login .brand{font-size:22px;font-weight:800;text-align:center;margin-bottom:18px}
.tabs{display:flex;gap:6px;margin-bottom:16px;background:var(--panel2);padding:4px;border-radius:10px}
.tab{flex:1;background:transparent;border:none;color:var(--muted);padding:9px;border-radius:7px;cursor:pointer;font-weight:700}
.tab.active{background:var(--brand);color:#fff}
.login .btn{width:100%;margin-top:6px}

/* toast / busy */
.toast{position:fixed;left:50%;bottom:32px;transform:translateX(-50%) translateY(20px);background:var(--panel2);
  color:var(--text);padding:12px 20px;border-radius:10px;border:1px solid var(--line);box-shadow:var(--shadow);
  opacity:0;pointer-events:none;transition:.25s;z-index:9999;font-weight:600;max-width:90vw}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.toast.ok{border-color:var(--ok)} .toast.err{border-color:var(--err)} .toast.warn{border-color:var(--warn)}
#busy{position:fixed;inset:0;background:rgba(0,0,0,.45);display:none;align-items:center;justify-content:center;z-index:9998}
#busy.show{display:flex}
.spin{width:42px;height:42px;border:4px solid rgba(255,255,255,.2);border-top-color:var(--brand);border-radius:50%;animation:sp 1s linear infinite}
@keyframes sp{to{transform:rotate(360deg)}}

/* modal */
.modal-bg{position:fixed;inset:0;background:rgba(0,0,0,.55);display:flex;align-items:center;justify-content:center;z-index:9990;padding:20px}
.modal{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:22px;width:520px;max-width:100%;max-height:90vh;overflow:auto;box-shadow:var(--shadow)}
.modal h3{margin-bottom:16px}
.modal .row{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.modal-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:18px}

/* ======= POS 收银台 ======= */
.pos{display:grid;grid-template-columns:1fr 380px;height:100vh}
.pos-left{display:flex;flex-direction:column;padding:18px;gap:14px;min-width:0}
.pos-scan{display:flex;gap:10px;align-items:center}
.pos-scan input{font-size:22px;padding:16px 18px;font-weight:600}
.pos-cart{flex:1;overflow:auto;border:1px solid var(--line);border-radius:var(--radius)}
.pos-cart table{font-size:15px}
.pos-cart thead th{padding:12px}
.pos-cart tbody td{padding:12px}
.pos-cart .qty{display:flex;align-items:center;gap:8px}
.pos-cart .qty button{width:30px;height:30px;border-radius:8px;font-size:18px;line-height:1;padding:0}
.pos-cart input.qnum{width:56px;text-align:center;padding:6px}
.pos-cart input.price{width:80px;text-align:right}
.pos-right{background:var(--panel);border-left:1px solid var(--line);padding:22px;display:flex;flex-direction:column}
.pos-brand{font-weight:800;font-size:20px;display:flex;justify-content:space-between;align-items:center;margin-bottom:8px}
.pos-total{margin-top:auto}
.pos-line{display:flex;justify-content:space-between;padding:8px 0;color:var(--muted)}
.pos-line.big{font-size:34px;font-weight:800;color:var(--text);border-top:1px solid var(--line);padding-top:16px;margin-top:8px}
.pos-pay{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:14px 0}
.pos-pay .chip{padding:12px;text-align:center;border:1px solid var(--line);border-radius:10px;cursor:pointer;font-weight:700}
.pos-pay .chip.active{border-color:var(--brand);background:rgba(79,140,255,.12);color:var(--brand)}
.pos-empty{display:flex;flex:1;align-items:center;justify-content:center;color:var(--muted);flex-direction:column;gap:8px}
.kbd{display:inline-block;padding:2px 7px;border:1px solid var(--line);border-radius:6px;background:var(--panel2);font-size:12px;font-family:monospace}

@media (max-width:920px){
  .app{grid-template-columns:1fr} .sidebar{flex-direction:row;overflow:auto;position:sticky;top:0;z-index:10}
  .nav{flex-direction:row} .sb-brand{display:none}
  .pos{grid-template-columns:1fr;height:auto} .pos-right{border-left:none;border-top:1px solid var(--line)}
}