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

:root {
    --primary: #2c3e50;
    --secondary: #3498db;
    --success: #27ae60;
    --danger: #e74c3c;
    --warning: #f39c12;
    --light: #ecf0f1;
    --dark: #34495e;
    --white: #ffffff;
    --gray: #95a5a6;
    --border: #bdc3c7;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--light);
    color: var(--dark);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
.header {
    background-color: var(--primary);
    color: var(--white);
    padding: 20px 0;
    margin-bottom: 30px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header h1 {
    font-size: 24px;
    font-weight: 600;
}

/* Navigation */
.nav {
    background-color: var(--white);
    padding: 15px 0;
    margin-bottom: 30px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.nav-links {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    gap: 20px;
    list-style: none;
}

.nav-links a {
    color: var(--dark);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.nav-links a:hover {
    background-color: var(--secondary);
    color: var(--white);
}

.nav-links a.active {
    background-color: var(--primary);
    color: var(--white);
}

/* Buttons */
.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background-color: var(--secondary);
    color: var(--white);
}

.btn-primary:hover {
    background-color: #2980b9;
}

.btn-success {
    background-color: var(--success);
    color: var(--white);
}

.btn-success:hover {
    background-color: #229954;
}

.btn-danger {
    background-color: var(--danger);
    color: var(--white);
}

.btn-danger:hover {
    background-color: #c0392b;
}

.btn-warning {
    background-color: var(--warning);
    color: var(--white);
}

.btn-warning:hover {
    background-color: #e67e22;
}

.btn-secondary {
    background-color: var(--gray);
    color: var(--white);
}

.btn-secondary:hover {
    background-color: #7f8c8d;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 12px;
}

/* Cards */
.card {
    background-color: var(--white);
    border-radius: 8px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.card-header {
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--light);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-header h2 {
    font-size: 20px;
    font-weight: 600;
    color: var(--primary);
}

.card-body {
    padding: 10px 0;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark);
}

.form-control {
    width: 100%;
    padding: 10px 15px;
    border: 2px solid var(--border);
    border-radius: 4px;
    font-size: 14px;
    transition: border-color 0.3s ease;
}

.form-control:focus {
    outline: none;
    border-color: var(--secondary);
}

textarea.form-control {
    resize: vertical;
    min-height: 100px;
}

select.form-control {
    cursor: pointer;
}

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

.table {
    width: 100%;
    border-collapse: collapse;
    background-color: var(--white);
}

.table thead {
    background-color: var(--primary);
    color: var(--white);
}

.table th,
.table td {
    padding: 12px 15px;
    text-align: left;
}

.table tbody tr {
    border-bottom: 1px solid var(--light);
    transition: background-color 0.2s ease;
}

.table tbody tr:hover {
    background-color: var(--light);
}

.table th {
    font-weight: 600;
}

/* Badges */
.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
}

.badge-success {
    background-color: var(--success);
    color: var(--white);
}

.badge-danger {
    background-color: var(--danger);
    color: var(--white);
}

.badge-warning {
    background-color: var(--warning);
    color: var(--white);
}

/* Alerts */
.alert {
    padding: 15px 20px;
    border-radius: 4px;
    margin-bottom: 20px;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    border-left: 4px solid var(--success);
}

.alert-danger {
    background-color: #f8d7da;
    color: #721c24;
    border-left: 4px solid var(--danger);
}

.alert-info {
    background-color: #d1ecf1;
    color: #0c5460;
    border-left: 4px solid var(--secondary);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
}

.modal.active {
    display: flex;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: var(--white);
    border-radius: 8px;
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    padding: 20px 25px;
    border-bottom: 2px solid var(--light);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--primary);
}

.modal-close {
    cursor: pointer;
    font-size: 28px;
    color: var(--gray);
    line-height: 1;
}

.modal-close:hover {
    color: var(--danger);
}

.modal-body {
    padding: 25px;
}

.modal-footer {
    padding: 15px 25px;
    border-top: 2px solid var(--light);
    display: flex;
    justify-content: flex-end;
    gap: 10px;
}

/* Grid */
.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -10px;
}

.col {
    padding: 0 10px;
    flex: 1;
}

.col-2 {
    flex: 0 0 50%;
}

.col-3 {
    flex: 0 0 33.333%;
}

.col-4 {
    flex: 0 0 25%;
}

/* Utilities */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.mt-20 {
    margin-top: 20px;
}

.mb-20 {
    margin-bottom: 20px;
}

.flex-between {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.gap-10 {
    gap: 10px;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        flex-direction: column;
    }
    
    .col-2, .col-3, .col-4 {
        flex: 0 0 100%;
    }
    
    .modal-content {
        width: 95%;
    }
}