* { box-sizing: border-box; }
body { margin:0; font-family:Arial,sans-serif; background:#f4f6f9; color:#333; }
.sidebar { position:fixed; left:0; top:0; width:240px; height:100vh; background:#1e293b; padding-top:25px; }
.sidebar h2 { color:white; text-align:center; margin-bottom:30px; font-size:21px; }
.sidebar a { display:block; color:#cbd5e1; text-decoration:none; padding:15px 25px; font-size:16px; }
.sidebar a:hover { background:#334155; color:white; }
.sidebar a.active { background:#2563eb; color:white; }
.main { margin-left:240px; padding:35px; }
h1 { margin-top:0; color:#1e293b; }
.card { background:white; padding:25px; border-radius:10px; box-shadow:0 2px 8px rgba(0,0,0,.08); margin-bottom:20px; }
.stat-card { width:280px; }
.stat-card h3 { margin:0 0 10px; color:#64748b; }
.stat-number { font-size:38px; font-weight:bold; color:#2563eb; }
.form-group { margin-bottom:18px; }
.form-group label { display:block; margin-bottom:7px; font-weight:bold; }
.form-group input, .form-group select { width:100%; max-width:500px; padding:12px; border:1px solid #cbd5e1; border-radius:6px; font-size:15px; }
.btn { display:inline-block; padding:11px 18px; border:none; border-radius:6px; color:white; background:#2563eb; cursor:pointer; text-decoration:none; font-size:14px; }
.btn:hover { opacity:.9; }
.btn-danger { background:#dc2626; }
.btn-warning { background:#f59e0b; }
.btn-success { background:#16a34a; }
table { width:100%; border-collapse:collapse; background:white; box-shadow:0 2px 8px rgba(0,0,0,.08); }
table th, table td { padding:13px; border-bottom:1px solid #e2e8f0; text-align:left; }
table th { background:#1e293b; color:white; }
table tr:hover { background:#f8fafc; }
.success { padding:13px; background:#dcfce7; color:#166534; border-radius:6px; margin-bottom:20px; }
.error { padding:13px; background:#fee2e2; color:#991b1b; border-radius:6px; margin-bottom:20px; }