:root {
  --primary: #4f6ef7;
  --primary-light: #eef0ff;
  --success: #22c55e;
  --success-light: #f0fdf4;
  --danger: #ef4444;
  --danger-light: #fff1f1;
  --warning: #f59e0b;
  --warning-light: #fffbeb;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-500: #6b7280;
  --gray-700: #374151;
  --gray-900: #111827;
  --radius: 12px;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
}
*{box-sizing:border-box;margin:0;padding:0;}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;background:#f0f2f8;color:var(--gray-900);min-height:100vh;}

/* Login */
.login-page{min-height:100vh;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);}
.login-box{background:white;border-radius:20px;padding:40px 36px;width:360px;max-width:95vw;box-shadow:var(--shadow-lg);}
.login-logo{text-align:center;font-size:48px;margin-bottom:12px;}
.login-title{text-align:center;font-size:20px;font-weight:700;margin-bottom:4px;}
.login-sub{text-align:center;font-size:13px;color:var(--gray-500);margin-bottom:24px;}

/* Header */
.header{background:linear-gradient(135deg,#4f6ef7 0%,#7c3aed 100%);color:white;padding:0 20px;height:60px;display:flex;align-items:center;justify-content:space-between;box-shadow:0 2px 8px rgba(79,110,247,0.3);position:sticky;top:0;z-index:100;}

/* Container */
.container{max-width:1200px;margin:0 auto;padding:18px 14px;}

/* Stats */
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:16px;}
.stat-card{background:white;border-radius:var(--radius);padding:14px 16px;box-shadow:var(--shadow);display:flex;align-items:center;gap:12px;}
.stat-icon{width:42px;height:42px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:20px;flex-shrink:0;}
.stat-icon.blue{background:var(--primary-light);}
.stat-icon.green{background:var(--success-light);}
.stat-icon.orange{background:var(--warning-light);}
.stat-icon.red{background:var(--danger-light);}
.stat-info .value{font-size:22px;font-weight:700;line-height:1.2;}
.stat-info .label{font-size:12px;color:var(--gray-500);margin-top:1px;}

/* Tabs */
.tabs{display:flex;background:white;border-radius:var(--radius);padding:5px;gap:3px;box-shadow:var(--shadow);margin-bottom:14px;width:fit-content;flex-wrap:wrap;}
.tab-btn{padding:7px 16px;border:none;background:transparent;border-radius:7px;font-size:13px;font-weight:500;color:var(--gray-500);cursor:pointer;transition:all .2s;}
.tab-btn:hover{color:var(--primary);}
.tab-btn.active{background:var(--primary);color:white;box-shadow:0 2px 8px rgba(79,110,247,.3);}

/* Panel */
.panel{background:white;border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden;}
.panel-header{padding:14px 18px;border-bottom:1px solid var(--gray-100);display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:8px;}
.panel-title{font-size:15px;font-weight:600;}
.panel-body{padding:18px;}
.panel-body.p0{padding:0;}

/* Buttons */
.btn{display:inline-flex;align-items:center;gap:5px;padding:8px 14px;border-radius:8px;border:none;font-size:13px;font-weight:500;cursor:pointer;transition:all .2s;text-decoration:none;}
.btn-primary{background:var(--primary);color:white;}
.btn-primary:hover{background:#3d5ce0;transform:translateY(-1px);box-shadow:0 4px 12px rgba(79,110,247,.3);}
.btn-success{background:var(--success);color:white;}
.btn-success:hover{background:#16a34a;}
.btn-danger{background:var(--danger);color:white;}
.btn-danger:hover{background:#dc2626;}
.btn-outline{background:white;color:var(--gray-700);border:1px solid var(--gray-200);}
.btn-outline:hover{border-color:var(--primary);color:var(--primary);}
.btn-sm{padding:5px 10px;font-size:12px;border-radius:6px;}
.w-full{width:100%;justify-content:center;}

/* Forms */
.form-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;}
.form-group{display:flex;flex-direction:column;gap:4px;}
.form-group.full{grid-column:1/-1;}
.form-label{font-size:13px;font-weight:500;color:var(--gray-700);}
.form-control{padding:9px 11px;border:1px solid var(--gray-200);border-radius:8px;font-size:13px;color:var(--gray-900);outline:none;background:var(--gray-50);transition:border-color .2s,box-shadow .2s;}
.form-control:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(79,110,247,.1);background:white;}

/* Table */
.table-wrap{overflow-x:auto;}
table{width:100%;border-collapse:collapse;}
thead th{background:var(--gray-50);padding:9px 13px;text-align:left;font-size:11px;font-weight:600;color:var(--gray-500);text-transform:uppercase;letter-spacing:.5px;border-bottom:1px solid var(--gray-200);white-space:nowrap;}
tbody tr{border-bottom:1px solid var(--gray-100);transition:background .15s;}
tbody tr:hover{background:var(--gray-50);}
tbody tr:last-child{border-bottom:none;}
tbody td{padding:10px 13px;font-size:13px;color:var(--gray-700);vertical-align:middle;}

/* Badges */
.badge{display:inline-flex;align-items:center;padding:2px 8px;border-radius:99px;font-size:11px;font-weight:600;}
.badge-blue{background:var(--primary-light);color:var(--primary);}
.badge-green{background:var(--success-light);color:#16a34a;}
.badge-red{background:var(--danger-light);color:var(--danger);}
.badge-orange{background:var(--warning-light);color:#b45309;}

/* Hours bar */
.hbar{display:flex;align-items:center;gap:7px;}
.hbar-track{flex:1;height:6px;background:var(--gray-200);border-radius:99px;overflow:hidden;min-width:50px;}
.hbar-fill{height:100%;border-radius:99px;transition:width .4s;}
.hbar-fill.hi{background:var(--success);}
.hbar-fill.mi{background:var(--warning);}
.hbar-fill.lo{background:var(--danger);}
.htext{font-size:13px;font-weight:600;white-space:nowrap;}
.htext.hi{color:var(--success);}
.htext.mi{color:var(--warning);}
.htext.lo{color:var(--danger);}

/* Avatar */
.stu-info{display:flex;align-items:center;gap:8px;}
.avatar{width:30px;height:30px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;color:white;flex-shrink:0;}
.stu-name{font-weight:600;font-size:13px;}
.stu-meta{font-size:11px;color:var(--gray-500);}

/* Subject tag */
.stag{display:inline-block;padding:1px 6px;border-radius:4px;font-size:11px;font-weight:600;margin-right:2px;}

/* Chips */
.chip{padding:4px 11px;border-radius:99px;border:1.5px solid var(--gray-200);background:white;font-size:12px;cursor:pointer;transition:all .15s;font-weight:500;color:var(--gray-700);}
.chip:hover{border-color:var(--primary);color:var(--primary);}

/* Search */
.search-input-wrap{position:relative;}
.search-input-wrap .icon{position:absolute;left:9px;top:50%;transform:translateY(-50%);color:var(--gray-500);font-size:13px;pointer-events:none;}
.search-input{padding:7px 11px 7px 28px;border:1px solid var(--gray-200);border-radius:8px;font-size:13px;outline:none;background:var(--gray-50);transition:all .2s;width:200px;}
.search-input:focus{border-color:var(--primary);background:white;box-shadow:0 0 0 3px rgba(79,110,247,.1);}

/* Action row */
.act-row{display:flex;gap:4px;}

/* Alerts */
.alert{padding:9px 13px;border-radius:8px;font-size:13px;display:flex;align-items:center;gap:7px;}
.alert-info{background:var(--primary-light);color:#1e40af;border:1px solid #bfdbfe;}
.alert-error{background:var(--danger-light);color:var(--danger);border:1px solid #fecaca;}
.alert-success{background:var(--success-light);color:#15803d;border:1px solid #bbf7d0;}

/* Empty state */
.empty-state{text-align:center;padding:42px 20px;color:var(--gray-500);}
.empty-icon{font-size:44px;margin-bottom:10px;}
.empty-state p{font-size:13px;}

/* Modal */
.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,0.42);backdrop-filter:blur(3px);display:flex;align-items:center;justify-content:center;z-index:999;animation:fadeIn .2s;}
.modal{background:white;border-radius:16px;width:440px;max-width:95vw;box-shadow:var(--shadow-lg);animation:slideUp .25s;overflow:hidden;}
.modal-header{padding:16px 18px 12px;border-bottom:1px solid var(--gray-100);display:flex;align-items:center;justify-content:space-between;}
.modal-title{font-size:15px;font-weight:700;}
.modal-close{width:26px;height:26px;border-radius:50%;border:none;background:var(--gray-100);cursor:pointer;font-size:14px;display:flex;align-items:center;justify-content:center;color:var(--gray-500);}
.modal-close:hover{background:var(--gray-200);}
.modal-body{padding:18px;}
.modal-footer{padding:12px 18px;border-top:1px solid var(--gray-100);display:flex;justify-content:flex-end;gap:8px;}

/* Dropdown */
.dropdown{position:relative;}
.dropdown-menu{position:absolute;right:0;top:calc(100% + 6px);background:white;border-radius:10px;box-shadow:var(--shadow-lg);min-width:150px;overflow:hidden;z-index:200;border:1px solid var(--gray-100);}
.dropdown-menu a{display:block;padding:9px 14px;font-size:13px;cursor:pointer;transition:background .15s;color:var(--gray-700);}
.dropdown-menu a:hover{background:var(--gray-50);}

/* Toast */
.toast-container{position:fixed;top:68px;right:14px;z-index:9999;display:flex;flex-direction:column;gap:7px;}
.toast{padding:11px 14px;border-radius:10px;background:white;box-shadow:var(--shadow-lg);font-size:13px;display:flex;align-items:center;gap:7px;min-width:190px;animation:slideInR .3s,fadeOut .3s 2.7s forwards;border-left:3px solid var(--primary);}
.toast.s{border-left-color:var(--success);}
.toast.e{border-left-color:var(--danger);}

/* Tab content */
.tab-content{display:none;}
.tab-content.active{display:block;}

/* Divider */
hr.div{border:none;border-top:1px solid var(--gray-100);margin:12px 0;}

@keyframes fadeIn{from{opacity:0}to{opacity:1}}
@keyframes slideUp{from{transform:translateY(18px);opacity:0}to{transform:translateY(0);opacity:1}}
@keyframes slideInR{from{transform:translateX(100%);opacity:0}to{transform:translateX(0);opacity:1}}
@keyframes fadeOut{from{opacity:1}to{opacity:0}}

@media(max-width:768px){
  .stats-grid{grid-template-columns:repeat(2,1fr);}
  .form-grid{grid-template-columns:1fr;}
  .search-input{width:140px;}
}