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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-color: #1e293b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

header h1 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 2em;
}

nav {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.nav-btn {
    padding: 12px 24px;
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.nav-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.nav-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.logout-btn {
    margin-left: auto;
    background: var(--danger-color) !important;
    color: white !important;
    border-color: var(--danger-color) !important;
}

.logout-btn:hover {
    background: #dc2626 !important;
    border-color: #dc2626 !important;
}

.section {
    display: none;
}

.section.active {
    display: block;
}

.section h2 {
    color: var(--text-color);
    margin-bottom: 25px;
    font-size: 1.8em;
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: 10px;
}

.form-container, .list-container {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.form-container h3, .list-container h3 {
    color: var(--text-color);
    margin-bottom: 20px;
    font-size: 1.3em;
}

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

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

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-group.checkbox {
    display: flex;
    align-items: center;
}

.form-group.checkbox label {
    margin-bottom: 0;
    display: flex;
    align-items: center;
    cursor: pointer;
}

.form-group.checkbox input[type="checkbox"] {
    width: auto;
    margin-right: 8px;
    cursor: pointer;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-block;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    background: #475569;
}

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

.btn-danger {
    background: var(--danger-color);
    color: white;
    padding: 8px 16px;
    font-size: 12px;
}

.btn-danger:hover {
    background: #dc2626;
}

.btn-warning {
    background: var(--warning-color);
    color: white;
    padding: 8px 16px;
    font-size: 12px;
}

.filter-group {
    display: flex;
    gap: 15px;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.filter-group label {
    display: flex;
    align-items: center;
    gap: 8px;
}

.filter-group select {
    padding: 8px 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
}

.table-container {
    overflow-x: auto;
}

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

table th {
    background: var(--primary-color);
    color: white;
    padding: 12px;
    text-align: left;
    font-weight: 600;
}

table td {
    padding: 12px;
    border-bottom: 1px solid var(--border-color);
}

table tr:hover {
    background: var(--bg-color);
}

.badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.badge-success {
    background: #d1fae5;
    color: #065f46;
}

.badge-warning {
    background: #fef3c7;
    color: #92400e;
}

.badge-danger {
    background: #fee2e2;
    color: #991b1b;
}

.badge-info {
    background: #dbeafe;
    color: #1e40af;
}

.calc-preview {
    background: var(--bg-color);
    padding: 15px;
    border-radius: 8px;
    margin: 20px 0;
    border-left: 4px solid var(--primary-color);
}

.info-box {
    background: #dbeafe;
    padding: 15px;
    border-radius: 8px;
    margin: 20px 0;
    border-left: 4px solid var(--primary-color);
}

.toast {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 16px 24px;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transform: translateY(-20px);
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

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

.toast.error {
    background: var(--danger-color);
}

.toast.info {
    background: var(--primary-color);
}

.loading {
    text-align: center;
    padding: 40px;
    color: var(--secondary-color);
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--secondary-color);
}

.empty-state h3 {
    margin-bottom: 10px;
    color: var(--text-color);
}

.action-buttons {
    display: flex;
    gap: 8px;
}

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

.modal.show {
    display: block;
}

.modal-content {
    background-color: var(--card-bg);
    margin: 5% auto;
    padding: 30px;
    border-radius: 12px;
    width: 90%;
    max-width: 600px;
    box-shadow: var(--shadow-lg);
}

.close {
    color: var(--secondary-color);
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}

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

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

/* Stats Grid */
.stats-container {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.stat-card {
    background: var(--bg-color);
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
}

.stat-card h4 {
    color: var(--secondary-color);
    font-size: 0.9em;
    margin-bottom: 10px;
}

.stat-card .stat-value {
    color: var(--text-color);
    font-size: 1.8em;
    font-weight: bold;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    header {
        padding: 20px;
    }

    header h1 {
        font-size: 1.5em;
    }

    .form-container, .list-container {
        padding: 20px;
    }

    nav {
        flex-direction: column;
    }

    .nav-btn {
        width: 100%;
    }

    table {
        font-size: 12px;
    }

    table th, table td {
        padding: 8px;
    }

    .modal-content {
        width: 95%;
        margin: 10% auto;
        padding: 20px;
    }

    .form-row {
        grid-template-columns: 1fr;
    }
}