:root{
  --bg:#f1f5f9; --panel:#ffffff; --ink:#0f172a; --muted:#64748b; --line:#e2e8f0;
  --accent:#2563eb; --accent-ink:#ffffff; --danger:#dc2626; --ok:#059669; --warn:#d97706;
  --radius:10px; --shadow:0 1px 2px rgba(15,23,42,.06),0 8px 24px rgba(15,23,42,.06);
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;font:14px/1.6 "Segoe UI",system-ui,-apple-system,"PingFang HK","Microsoft JhengHei","Noto Sans TC",sans-serif;color:var(--ink);background:var(--bg);overflow:hidden}
button,input,select,textarea{font:inherit;color:inherit}

.topbar{display:flex;align-items:center;gap:10px;padding:8px 14px;background:var(--panel);border-bottom:1px solid var(--line);box-shadow:var(--shadow);position:relative;z-index:20}
.brand{display:flex;align-items:center;gap:8px;font-weight:700;white-space:nowrap}
.brand .logo{font-size:20px}
.title-input{flex:0 1 340px;padding:7px 10px;border:1px solid var(--line);border-radius:8px;background:#f8fafc}
.title-input:focus{outline:2px solid var(--accent);background:#fff}
.spacer{flex:1}

.btn{padding:7px 12px;border:1px solid var(--line);background:#fff;border-radius:8px;cursor:pointer;white-space:nowrap;transition:.12s}
.btn:hover{background:#f8fafc;border-color:#cbd5e1}
.btn.primary{background:var(--accent);color:var(--accent-ink);border-color:var(--accent);font-weight:600}
.btn.primary:hover{background:#1d4ed8}
.btn.tiny{padding:4px 8px;font-size:12px;border-radius:6px}
.btn.wide{width:100%;margin-top:6px}
.btn.danger{color:var(--danger);border-color:#fecaca}
.btn.toggle.on{background:var(--accent);color:#fff;border-color:var(--accent)}
.btn[disabled]{opacity:.55;cursor:progress}

.menu-wrap{position:relative}
.menu{display:none;position:absolute;right:0;top:calc(100% + 6px);background:#fff;border:1px solid var(--line);border-radius:10px;box-shadow:var(--shadow);min-width:200px;padding:6px;z-index:30}
.menu.open{display:block}
.menu button{display:block;width:100%;text-align:left;padding:8px 10px;border:0;background:none;border-radius:6px;cursor:pointer}
.menu button:hover{background:#f1f5f9}

.layout{display:flex;height:calc(100vh - 53px)}
.sidebar{width:340px;min-width:340px;background:var(--panel);border-right:1px solid var(--line);display:flex;flex-direction:column;overflow:hidden}
.tabs{display:flex;border-bottom:1px solid var(--line)}
.tab{flex:1;padding:10px 4px;border:0;background:none;cursor:pointer;color:var(--muted);border-bottom:2px solid transparent;font-weight:600}
.tab.active{color:var(--accent);border-bottom-color:var(--accent)}
.panel{display:none;padding:14px;overflow-y:auto;flex:1}
.panel.active{display:block}

.field{margin-bottom:12px}
label{display:block;font-size:12px;color:var(--muted);font-weight:600;margin-bottom:4px}
label.inline{display:inline-flex;align-items:center;gap:6px;font-size:12px;margin:0;white-space:nowrap}
label.block{display:block;margin:8px 0}
.tiny-label{font-size:12px;color:var(--muted);white-space:nowrap;flex:none}
input[type=text],input[type=number],select,textarea{width:100%;padding:7px 9px;border:1px solid var(--line);border-radius:8px;background:#fff}
input:focus,select:focus,textarea:focus{outline:2px solid #bfdbfe;border-color:var(--accent)}
textarea{resize:vertical}
.hint{color:var(--muted);font-size:12px;margin:6px 0}
.row-between{display:flex;align-items:center;justify-content:space-between;gap:8px;margin:10px 0 6px}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.grid2 label{display:block}
.grid2 input{margin-top:3px}

.list{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:6px}
.list li{display:flex;align-items:center;gap:8px;padding:7px 9px;border:1px solid var(--line);border-radius:8px;background:#fff}
.list li .grow{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.list li.student{cursor:grab}
.list li.student:active{cursor:grabbing}
.list li .seatbadge{font-size:11px;color:var(--muted);background:#f1f5f9;border-radius:5px;padding:1px 6px}
.list li .x{border:0;background:none;color:var(--muted);cursor:pointer;font-size:15px;line-height:1}
.list li .x:hover{color:var(--danger)}
.list li.rule{align-items:flex-start;flex-direction:column;gap:4px}
.rule-head{display:flex;width:100%;gap:6px;align-items:center}
.badge{font-size:10px;font-weight:700;border-radius:5px;padding:2px 6px;text-transform:uppercase;letter-spacing:.03em}
.badge.hard{background:#fee2e2;color:#b91c1c}
.badge.soft{background:#e0f2fe;color:#0369a1}
.badge.bad{background:#fef3c7;color:#92400e}
.rule-fields{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:8px 0}
.rule-fields .full{grid-column:1/-1}

.palette{display:grid;grid-template-columns:1fr 1fr;gap:6px}
.palette button{padding:7px 6px;border:1px solid var(--line);border-radius:8px;background:#fff;cursor:pointer;font-size:12px;text-align:left}
.palette button:hover{border-color:var(--accent);background:#f8fafc}
.inspector{margin:12px 0;padding:10px;border:1px solid var(--line);border-radius:10px;background:#f8fafc;display:none}
.inspector.show{display:block}
.inspector h4{margin:0 0 8px}
.capacity{margin-top:12px;padding:10px;border-radius:10px;background:#f8fafc;border:1px solid var(--line);font-size:13px}

.stage{flex:1;display:flex;flex-direction:column;min-width:0}
.toolbar{display:flex;align-items:center;gap:8px;padding:8px 12px;background:var(--panel);border-bottom:1px solid var(--line);flex-wrap:wrap}
.zoom{font-size:12px;color:var(--muted);min-width:44px;text-align:center}
.canvas-wrap{flex:1;overflow:auto;padding:24px;display:flex;align-items:flex-start;justify-content:center;background:
  radial-gradient(circle at 1px 1px,#dbe3ee 1px,transparent 0) 0 0/22px 22px,var(--bg)}
#svgHost svg{background:#fff;box-shadow:0 6px 28px rgba(15,23,42,.13);border-radius:6px;touch-action:none}
.status{padding:8px 12px;background:var(--panel);border-top:1px solid var(--line);font-size:12.5px;max-height:150px;overflow-y:auto}
.status .ok{color:var(--ok);font-weight:600}
.status .bad{color:var(--danger);font-weight:600}
.status ul{margin:6px 0 0;padding-left:18px}

.toast{position:fixed;bottom:22px;left:50%;transform:translateX(-50%) translateY(20px);background:#0f172a;color:#fff;padding:10px 16px;border-radius:10px;opacity:0;pointer-events:none;transition:.25s;z-index:50}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.drop-target{filter:drop-shadow(0 0 6px var(--accent))}
@media (max-width:900px){
  .layout{flex-direction:column;height:auto;overflow:auto}
  body{overflow:auto}
  .sidebar{width:100%;min-width:0}
  .panel{max-height:44vh}
}
.toolbar select{width:auto}