:root{
  --bg:#f1f5f9; --card:#ffffff; --ink:#0f172a; --muted:#64748b;
  --line:#e2e8f0; --brand1:#2563eb; --brand2:#0ea5e9;
  --green1:#10b981; --green2:#0ea5e9; --red1:#fb7185; --red2:#f97316;
  --amber:#f59e0b; --violet:#7c3aed;
  --radius:16px; --shadow:0 10px 30px rgba(15,23,42,.08);
}
*{box-sizing:border-box}
body{margin:0;font-family:"Segoe UI",Poppins,Inter,Arial,sans-serif;background:var(--bg);color:var(--ink)}
a{color:inherit}
.app{display:flex;min-height:100vh}
/* Sidebar */
.sidebar{width:268px;background:#0f172a;color:#e2e8f0;position:fixed;inset:0 auto 0 0;display:flex;flex-direction:column;z-index:1001;transition:transform .25s}
.brand{display:flex;align-items:center;gap:12px;padding:20px 18px;border-bottom:1px solid rgba(255,255,255,.08)}
.brand img{width:46px;height:46px;object-fit:contain;background:#fff;border-radius:12px;padding:4px}
.brand b{font-size:17px;display:block;line-height:1.1}
.brand span{font-size:12px;color:#94a3b8}
.nav{padding:14px;display:flex;flex-direction:column;gap:6px;overflow:auto}
.nav a{display:flex;align-items:center;gap:10px;padding:11px 12px;border-radius:10px;text-decoration:none;color:#cbd5e1;font-weight:600;font-size:14px}
.nav a:hover{background:rgba(255,255,255,.07);color:#fff}
.nav a.active{background:linear-gradient(90deg,var(--brand1),var(--brand2));color:#fff;box-shadow:0 8px 20px rgba(37,99,235,.35)}
.nav .sec{font-size:11px;letter-spacing:.12em;color:#64748b;margin:12px 4px 4px;font-weight:800}
.side-foot{margin-top:auto;padding:14px;border-top:1px solid rgba(255,255,255,.08);font-size:12px;color:#94a3b8}
/* Main */
.main{flex:1;margin-left:268px;min-width:0}
.topbar{position:sticky;top:0;z-index:1000;background:rgba(255,255,255,.9);backdrop-filter:blur(10px);border-bottom:1px solid var(--line);padding:14px 22px;display:flex;align-items:center;gap:14px}
.menu-btn{display:none;border:1px solid var(--line);background:#fff;border-radius:10px;width:42px;height:42px;font-size:18px;cursor:pointer}
.page-title{margin:0;font-size:20px}
.page-sub{margin:2px 0 0;font-size:13px;color:var(--muted)}
.top-actions{margin-left:auto;display:flex;gap:8px;align-items:center}
.content{padding:22px;max-width:1250px;margin:0 auto}
/* Cards / grids */
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.grid4{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:18px}
.card h3{margin:0 0 4px;font-size:17px}
.card p.sub{margin:0 0 14px;color:var(--muted);font-size:13px}
.stat{display:flex;gap:12px;align-items:center}
.stat .ico{width:48px;height:48px;border-radius:14px;display:flex;align-items:center;justify-content:center;font-size:22px;color:#fff;flex-shrink:0}
.stat b{font-size:24px;display:block;line-height:1}
.stat span{font-size:12px;color:var(--muted);font-weight:700}
/* Forms */
label.lbl{display:block;font-size:12px;font-weight:800;color:#334155;margin:0 0 6px;letter-spacing:.02em}
input.in,select.in,textarea.in{width:100%;padding:11px 12px;border:1px solid #cbd5e1;border-radius:10px;font-size:14px;outline:none;background:#fff;font-family:inherit}
input.in:focus,select.in:focus,textarea.in:focus{border-color:var(--brand1);box-shadow:0 0 0 3px rgba(37,99,235,.15)}
input.in:disabled{background:#f1f5f9;color:#0f172a;font-weight:600}
textarea.in{min-height:84px;resize:vertical}
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.btn{border:none;border-radius:10px;padding:11px 16px;font-weight:800;font-size:14px;cursor:pointer;display:inline-flex;align-items:center;gap:8px;justify-content:center;text-decoration:none}
.btn-primary{background:linear-gradient(90deg,var(--brand1),var(--brand2));color:#fff}
.btn-green{background:linear-gradient(90deg,var(--green1),var(--green2));color:#fff}
.btn-red{background:linear-gradient(90deg,var(--red1),var(--red2));color:#fff}
.btn-ghost{background:#eef2f7;color:#0f172a}
.btn-dark{background:#0f172a;color:#fff}
.btn:disabled{opacity:.55;cursor:not-allowed}
.btn-sm{padding:8px 11px;font-size:13px;border-radius:8px}
/* Tables */
.tbl-wrap{overflow:auto;border:1px solid var(--line);border-radius:12px;margin-top:12px}
table.tbl{width:100%;border-collapse:collapse;background:#fff;font-size:13px;min-width:640px}
.tbl th{background:#0f172a;color:#fff;text-align:left;padding:10px;font-size:12px;letter-spacing:.03em;white-space:nowrap}
.tbl td{padding:10px;border-bottom:1px solid #eef2f7;vertical-align:top}
.tbl tr:last-child td{border-bottom:none}
.pill{display:inline-block;padding:3px 10px;border-radius:999px;font-size:11px;font-weight:800}
.pill-issued{background:#e0f2fe;color:#0369a1}
.pill-returned{background:#dcfce7;color:#166534}
.pill-teacher{background:#ede9fe;color:#6d28d9}
.pill-student{background:#e0f2fe;color:#075985}
.pill-lost{background:#fee2e2;color:#b91c1c}
.pill-damage{background:#ffedd5;color:#c2410c}
/* Helpers */
.muted{color:var(--muted);font-size:13px}
.divider{height:1px;background:var(--line);margin:14px 0}
.toast{position:fixed;bottom:20px;right:20px;display:flex;flex-direction:column;gap:8px;z-index:3000}
.toast div{background:#0f172a;color:#fff;padding:12px 16px;border-radius:12px;box-shadow:var(--shadow);font-size:14px;max-width:min(92vw,380px)}
.seg{display:flex;gap:10px;flex-wrap:wrap}
.seg label{display:flex;gap:8px;align-items:center;background:#f8fafc;border:1px solid var(--line);padding:10px 12px;border-radius:10px;font-size:13px;font-weight:700;cursor:pointer}
.search-list{border:1px solid var(--line);border-radius:10px;max-height:220px;overflow:auto;margin-top:8px}
.search-list .it{padding:10px 12px;cursor:pointer;font-size:14px;border-bottom:1px solid #f1f5f9}
.search-list .it:last-child{border-bottom:none}
.search-list .it:hover,.search-list .it.on{background:#dbeafe;color:#1d4ed8;font-weight:700}
.selected-bar{margin-top:8px;background:#eff6ff;border:1px solid #bfdbfe;color:#1e3a8a;border-radius:10px;padding:10px 12px;font-weight:700;font-size:14px}
.overlay{position:fixed;inset:0;background:rgba(2,6,23,.5);opacity:0;pointer-events:none;transition:.2s;z-index:1000}
.overlay.on{opacity:1;pointer-events:auto}
/* Modal */
.modal{position:fixed;inset:0;display:none;align-items:center;justify-content:center;background:rgba(2,6,23,.55);z-index:2000;padding:16px}
.modal.on{display:flex}
.modal-card{background:#fff;border-radius:16px;padding:20px;width:min(520px,100%);box-shadow:var(--shadow)}
.modal-card h3{margin:0 0 12px}
/* Scanner */
.scanner{position:fixed;inset:0;display:none;align-items:center;justify-content:center;background:rgba(2,6,23,.85);z-index:2500;padding:16px}
.scanner.on{display:flex}
.scanner-card{background:#fff;border-radius:18px;padding:14px;width:min(480px,100%)}
.scan-view{position:relative;border-radius:14px;overflow:hidden;background:#020617;aspect-ratio:3/4}
.scan-view video{width:100%;height:100%;object-fit:cover}
.scan-frame{position:absolute;inset:14% 10%;border:3px solid rgba(16,185,129,.95);border-radius:16px;box-shadow:0 0 0 9999px rgba(2,6,23,.3)}
.pager{display:flex;gap:10px;align-items:center;justify-content:center;margin-top:12px}
.kbd{font-size:11px;background:#f1f5f9;border:1px solid var(--line);border-radius:6px;padding:2px 6px;color:#475569}
@media(max-width:1020px){.grid4{grid-template-columns:1fr 1fr}.grid3{grid-template-columns:1fr 1fr}}
@media(max-width:860px){
  .sidebar{transform:translateX(-100%)}
  .sidebar.open{transform:none}
  .main{margin-left:0}
  .menu-btn{display:block}
  .grid2,.grid3,.grid4,.form-grid{grid-template-columns:1fr}
  .content{padding:14px}
}