:root{
  --ap:#1565C0;--apd:#0D47A1;--asb:#1A237E;--asw:255px;--ath:58px;
  --ac:#E53935;--ag:#2E7D32;--aw:#F57F17;
  --af:'Noto Sans Bengali',sans-serif;--ar:6px;
  --shadow:0 2px 8px rgba(0,0,0,.1);--shadow-md:0 4px 20px rgba(0,0,0,.15);
}
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
body.admin-body{font-family:var(--af);font-size:14px;color:#263238;background:#f5f7fa;display:flex;min-height:100vh}
a{text-decoration:none;color:inherit}ul{list-style:none}img{max-width:100%}

/* Sidebar */
.admin-sidebar{width:var(--asw);background:var(--asb);min-height:100vh;position:fixed;left:0;top:0;z-index:1000;display:flex;flex-direction:column;transition:transform .3s;overflow-y:auto;scrollbar-width:thin;scrollbar-color:rgba(255,255,255,.2) transparent}
.sidebar-header{padding:14px 16px;border-bottom:1px solid rgba(255,255,255,.1);display:flex;align-items:center;justify-content:space-between;background:rgba(0,0,0,.2)}
.sidebar-logo{display:flex;align-items:center;gap:10px}
.sidebar-logo i{font-size:26px;color:#fff;opacity:.9}
.sidebar-title{display:block;color:#fff;font-size:13px;font-weight:700;line-height:1.2}
.sidebar-subtitle{display:block;color:rgba(255,255,255,.55);font-size:11px}
.sidebar-close{display:none;background:transparent;border:none;color:rgba(255,255,255,.7);font-size:18px;cursor:pointer}
.sidebar-nav{flex:1;padding:8px 0}
.nav-section{margin-bottom:2px}
.nav-section-label{display:block;padding:8px 16px 3px;font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:.5px;color:rgba(255,255,255,.38)}
.nav-item,.nav-btn{display:flex;align-items:center;gap:10px;width:100%;padding:8px 16px;color:rgba(255,255,255,.72);font-size:13px;font-family:var(--af);background:transparent;border:none;cursor:pointer;text-align:left;transition:all .15s}
.nav-item:hover,.nav-btn:hover{color:#fff;background:rgba(255,255,255,.1);padding-left:22px}
.nav-item.active{color:#fff;background:var(--ap);font-weight:700}
.nav-item i,.nav-btn i{width:17px;text-align:center;font-size:13px;flex-shrink:0}
.nav-form{margin:0}
.sidebar-overlay{display:none;position:fixed;inset:0;background:rgba(0,0,0,.5);z-index:999}

/* Main */
.admin-main{margin-left:var(--asw);flex:1;display:flex;flex-direction:column;min-height:100vh;transition:margin-left .3s}
.admin-topbar{height:var(--ath);background:#fff;border-bottom:1px solid #dde1e9;display:flex;align-items:center;justify-content:space-between;padding:0 22px;position:sticky;top:0;z-index:100;box-shadow:var(--shadow)}
.topbar-toggle{background:transparent;border:none;font-size:20px;cursor:pointer;color:#263238;padding:4px 8px;border-radius:var(--ar);display:none}
.topbar-toggle:hover{background:#f1f3f4}
.breadcrumb{display:flex;align-items:center;gap:5px;font-size:13px;color:#78909C}
.breadcrumb a{color:var(--ap)}
.breadcrumb a:hover{text-decoration:underline}
.breadcrumb .sep{font-size:9px}
.topbar-right{display:flex;align-items:center;gap:10px}
.topbar-user{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:700}
.topbar-user i{font-size:22px;color:var(--ap)}
.topbar-btn{width:34px;height:34px;border-radius:50%;display:flex;align-items:center;justify-content:center;background:#f1f3f4;color:#263238;transition:background .15s}
.topbar-btn:hover{background:#e0e0e0}

/* Content */
.admin-content{flex:1;padding:22px}

/* Alerts */
.alert{display:flex;align-items:center;gap:10px;padding:11px 16px;border-radius:var(--ar);margin-bottom:18px;font-size:13px;animation:slideIn .2s ease}
@keyframes slideIn{from{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:translateY(0)}}
.alert-success{background:#E8F5E9;color:#1B5E20;border:1px solid #A5D6A7}
.alert-error{background:#FFEBEE;color:#B71C1C;border:1px solid #FFCDD2}
.alert-close{margin-left:auto;background:transparent;border:none;cursor:pointer;font-size:16px;opacity:.7}

/* Stats */
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-bottom:22px}
.stat-card{background:#fff;border-radius:var(--ar);padding:18px;box-shadow:var(--shadow);display:flex;align-items:center;gap:14px;border-left:4px solid var(--ap);transition:transform .15s,box-shadow .15s}
.stat-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-md)}
.stat-card.red{border-left-color:var(--ac)}.stat-card.green{border-left-color:var(--ag)}.stat-card.warn{border-left-color:var(--aw)}
.stat-icon{width:48px;height:48px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:20px;color:#fff;background:var(--ap);flex-shrink:0}
.stat-card.red .stat-icon{background:var(--ac)}.stat-card.green .stat-icon{background:var(--ag)}.stat-card.warn .stat-icon{background:var(--aw)}
.stat-value{font-size:24px;font-weight:700;line-height:1;margin-bottom:3px}
.stat-label{font-size:12px;color:#78909C}

/* Card */
.admin-card{background:#fff;border-radius:var(--ar);box-shadow:var(--shadow);margin-bottom:18px;overflow:hidden}
.card-header{display:flex;align-items:center;justify-content:space-between;padding:14px 18px;border-bottom:1px solid #eef0f4;background:#f8f9fa}
.card-header h3{font-size:14px;font-weight:700;display:flex;align-items:center;gap:7px}
.card-header h3 i{color:var(--ap)}
.card-body{padding:18px}

/* Table */
.admin-table-wrap{overflow-x:auto}
.admin-table{width:100%;border-collapse:collapse;font-size:13px}
.admin-table th{background:#f5f7fa;padding:9px 14px;text-align:left;font-weight:700;color:#78909C;font-size:11px;text-transform:uppercase;letter-spacing:.3px;border-bottom:2px solid #dde1e9;white-space:nowrap}
.admin-table td{padding:11px 14px;border-bottom:1px solid #f1f3f4;vertical-align:middle}
.admin-table tr:hover td{background:#fafafa}
.admin-table tr:last-child td{border:none}

/* Badges */
.badge{display:inline-block;padding:3px 10px;border-radius:20px;font-size:11px;font-weight:700}
.badge-success{background:#E8F5E9;color:#2E7D32}.badge-danger{background:#FFEBEE;color:#C62828}
.badge-warning{background:#FFF8E1;color:#F57F17}.badge-info{background:#E3F2FD;color:var(--ap)}

/* Buttons */
.btn{display:inline-flex;align-items:center;gap:6px;padding:7px 16px;border-radius:var(--ar);font-family:var(--af);font-size:13px;font-weight:600;border:none;cursor:pointer;transition:all .15s}
.btn-primary{background:var(--ap);color:#fff}.btn-primary:hover{background:var(--apd);color:#fff}
.btn-success{background:var(--ag);color:#fff}.btn-success:hover{background:#1B5E20;color:#fff}
.btn-danger{background:var(--ac);color:#fff}.btn-danger:hover{background:#B71C1C;color:#fff}
.btn-warn{background:var(--aw);color:#fff}
.btn-sm{padding:5px 11px;font-size:12px}
.btn-icon{width:30px;height:30px;padding:0;display:inline-flex;align-items:center;justify-content:center;border-radius:var(--ar);background:#f5f7fa;color:#263238;border:1px solid #dde1e9;transition:all .15s;font-size:13px}
.btn-icon:hover{background:#e0e0e0}
.btn-icon.edit:hover{background:var(--ap);color:#fff;border-color:var(--ap)}
.btn-icon.delete:hover{background:var(--ac);color:#fff;border-color:var(--ac)}

/* Forms */
.form-group{margin-bottom:14px}
.form-group label{display:block;font-size:13px;font-weight:700;color:#263238;margin-bottom:5px}
.form-control{width:100%;padding:8px 13px;border:1px solid #dde1e9;border-radius:var(--ar);font-family:var(--af);font-size:13px;color:#263238;background:#fff;transition:border-color .15s,box-shadow .15s}
.form-control:focus{outline:none;border-color:var(--ap);box-shadow:0 0 0 3px rgba(21,101,192,.12)}
.form-control.is-invalid{border-color:var(--ac)}
.invalid-feedback{color:var(--ac);font-size:12px;margin-top:3px}
textarea.form-control{resize:vertical;min-height:90px}
.form-row{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.form-actions{display:flex;align-items:center;gap:10px;padding-top:8px;border-top:1px solid #eef0f4;margin-top:18px}

/* Filter bar */
.filter-bar{display:flex;align-items:center;gap:8px;padding:13px 18px;background:#f8f9fa;border-bottom:1px solid #dde1e9;flex-wrap:wrap}
.filter-bar .form-control{max-width:220px}
.ms-auto{margin-left:auto}
.pagination-wrap{display:flex;justify-content:flex-end;padding:14px 18px;border-top:1px solid #eef0f4}

/* Photo / thumb */
.photo-preview{object-fit:cover;border:2px solid #dde1e9;border-radius:var(--ar);display:block;margin-bottom:8px}
.teacher-thumb{width:44px;height:50px;object-fit:cover;border:1px solid #dde1e9}

/* Empty state */
.empty-state{text-align:center;padding:55px 20px;color:#78909C}
.empty-state i{font-size:48px;opacity:.3;display:block;margin-bottom:14px}
.empty-state h3{font-size:17px;margin-bottom:6px;color:#263238}

/* Login */
.admin-login-page{min-height:100vh;background:linear-gradient(135deg,#1A237E,#1565C0);display:flex;align-items:center;justify-content:center;padding:20px}
.login-card{background:#fff;border-radius:12px;padding:38px;width:100%;max-width:420px;box-shadow:0 20px 60px rgba(0,0,0,.3)}
.login-logo{text-align:center;margin-bottom:28px}
.login-logo i{font-size:48px;color:var(--ap);display:block;margin-bottom:12px}
.login-logo h2{font-size:19px;color:#263238;margin-bottom:5px}
.login-logo p{font-size:13px;color:#78909C}

/* Config tabs */
.config-tab{display:inline-flex;align-items:center;gap:6px;padding:7px 14px;background:#f5f7fa;border:1px solid #dde1e9;border-radius:var(--ar);font-size:13px;color:#546E7A;cursor:pointer;text-decoration:none;transition:all .15s;font-family:var(--af)}
.config-tab:hover{background:#e3f2fd;color:var(--ap);border-color:#90CAF9}
.config-tab.active-tab{background:var(--ap);color:#fff;border-color:var(--ap)}

/* Responsive */
@media(max-width:1024px){.stats-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:768px){
  .admin-sidebar{transform:translateX(-100%)}.admin-sidebar.open{transform:translateX(0)}
  .sidebar-overlay.show{display:block}.sidebar-close{display:block}
  .topbar-toggle{display:flex}.admin-main{margin-left:0}
  .stats-grid{grid-template-columns:1fr 1fr}.form-row{grid-template-columns:1fr}
  .admin-content{padding:14px}
}
@media(max-width:480px){.stats-grid{grid-template-columns:1fr}}