* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

/* Header */
.header {
    background: white;
    padding: 20px 30px;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.header h1 {
    color: #667eea;
    font-size: 28px;
}

.header .user-info {
    display: flex;
    align-items: center;
    gap: 15px;
}

.header .username {
    color: #333;
    font-weight: 500;
}

/* Navigation */
.nav {
    background: white;
    padding: 15px 30px;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    margin-bottom: 30px;
}

.nav ul {
    list-style: none;
    display: flex;
    gap: 30px;
}

.nav a {
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.nav a:hover {
    color: #764ba2;
}

/* Cards */
.card {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    margin-bottom: 30px;
}

.card h2 {
    color: #333;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid #f0f0f0;
}

/* Forms */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #333;
    font-weight: 500;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 6px;
    font-size: 14px;
    transition: border-color 0.3s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #667eea;
}

/* Buttons */
.btn {
    padding: 12px 30px;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
}

.btn-success {
    background: #28a745;
    color: white;
}

.btn-success:hover {
    background: #218838;
}

.btn-danger {
    background: #dc3545;
    color: white;
}

.btn-danger:hover {
    background: #c82333;
}

.btn-sm {
    padding: 8px 20px;
    font-size: 14px;
}

/* Tables */
.table-responsive {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

table th,
table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #e0e0e0;
}

table th {
    background: #f8f9fa;
    color: #333;
    font-weight: 600;
}

table tbody tr:hover {
    background: #f8f9fa;
}

/* Login Page */
.login-container {
    max-width: 450px;
    margin: 100px auto;
}

.login-card {
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.2);
}

.login-card h2 {
    text-align: center;
    color: #667eea;
    margin-bottom: 30px;
    border: none;
}

/* Alerts */
.alert {
    padding: 15px 20px;
    border-radius: 6px;
    margin-bottom: 20px;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.alert-info {
    background: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

/* Stats Dashboard */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: white;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    text-align: center;
}

.stat-card h3 {
    color: #666;
    font-size: 14px;
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-card .number {
    font-size: 36px;
    font-weight: bold;
    color: #667eea;
}

/* Payment Link */
.payment-link {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 6px;
    border: 2px dashed #667eea;
    margin-top: 20px;
}

.payment-link input {
    width: 100%;
    padding: 10px;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    font-family: monospace;
}

/* Responsive */
@media (max-width: 768px) {
    .header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .nav ul {
        flex-direction: column;
        gap: 10px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
}