/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --warning-color: #f39c12;
    --info-color: #16a085;
    --light-bg: #ecf0f1;
    --white: #ffffff;
    --text-dark: #2c3e50;
    --text-light: #7f8c8d;
    --border-color: #dfe6e9;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
    --shadow-lg: 0 5px 20px rgba(0,0,0,0.15);
}

body {
    font-family: 'Prompt', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-dark);
    line-height: 1.6;
}

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

/* Header */
.header {
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.logo i {
    font-size: 2rem;
}

.nav-menu {
    display: flex;
    gap: 1rem;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    color: var(--text-dark);
    border-radius: 8px;
    transition: all 0.3s ease;
    font-weight: 500;
}

.nav-item:hover {
    background: var(--light-bg);
    color: var(--primary-color);
}

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

/* Main Content */
.main-content {
    padding: 2rem 0;
    min-height: calc(100vh - 100px);
}

.page {
    display: none;
    animation: fadeIn 0.5s ease;
}

.page.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.page-title {
    font-size: 2rem;
    color: var(--white);
    margin-bottom: 2rem;
    display: flex;
    align-items: center;
    gap: 15px;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: var(--white);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 1.5rem;
    transition: all 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    color: var(--white);
}

.stat-icon.blue { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); }
.stat-icon.green { background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%); }
.stat-icon.orange { background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%); }
.stat-icon.cyan { background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%); }
.stat-icon.purple { background: linear-gradient(135deg, #a8edea 0%, #fed6e3 100%); }
.stat-icon.red { background: linear-gradient(135deg, #ff9a9e 0%, #fecfef 100%); }

.stat-info h3 {
    font-size: 2rem;
    color: var(--text-dark);
    font-weight: 700;
}

.stat-info p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* Cards Grid */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 1.5rem;
}

.card {
    background: var(--white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--light-bg);
}

.card-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 10px;
}

.card-badge {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.badge-electric {
    background: #fff3cd;
    color: #856404;
}

.badge-water {
    background: #d1ecf1;
    color: #0c5460;
}

.badge-active {
    background: #d4edda;
    color: #155724;
}

.badge-inactive {
    background: #f8d7da;
    color: #721c24;
}

.card-body {
    margin-bottom: 1rem;
}

.card-info {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.info-row {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-dark);
}

.info-row i {
    width: 20px;
    color: var(--primary-color);
}

.card-actions {
    display: flex;
    gap: 0.5rem;
    justify-content: flex-end;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-family: 'Prompt', sans-serif;
}

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

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

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

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

.btn-secondary:hover {
    background: #6c7a89;
}

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

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

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

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

/* Filter Tabs */
.filter-tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: 'Prompt', sans-serif;
}

.tab-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

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

/* Form Styles */
.form-card {
    background: var(--white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.form-card h2 {
    margin-bottom: 1.5rem;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 10px;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-weight: 500;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 8px;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: 'Prompt', sans-serif;
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.form-group input[readonly] {
    background: var(--light-bg);
    cursor: not-allowed;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    margin-top: 2rem;
}

/* Calculation Preview */
.calculation-preview {
    background: var(--light-bg);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.calculation-preview h3 {
    margin-bottom: 1rem;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 10px;
}

#calculation-details {
    background: var(--white);
    border-radius: 8px;
    padding: 1rem;
}

.calc-row {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.calc-row:last-child {
    border-bottom: none;
}

.calc-row.total {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--primary-color);
    border-top: 2px solid var(--primary-color);
    padding-top: 1rem;
    margin-top: 1rem;
}

.calc-label {
    color: var(--text-dark);
}

.calc-value {
    font-weight: 600;
    color: var(--text-dark);
}

/* Filter Section */
.filter-section {
    background: var(--white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

/* History Grid */
.history-grid {
    display: grid;
    gap: 1.5rem;
}

.history-card {
    background: var(--white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 1.5rem;
    align-items: center;
    transition: all 0.3s ease;
}

.history-card:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow-lg);
}

.history-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--white);
}

.history-icon.electric {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.history-icon.water {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

.history-info h3 {
    font-size: 1.2rem;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.history-details {
    display: flex;
    gap: 1.5rem;
    color: var(--text-light);
    font-size: 0.9rem;
}

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

.amount-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
}

.amount-units {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-top: 0.25rem;
}

.status-badge {
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 500;
    display: inline-block;
    margin-top: 0.5rem;
}

.status-paid {
    background: #d4edda;
    color: #155724;
}

.status-unpaid {
    background: #f8d7da;
    color: #721c24;
}

/* Bills List */
.bills-list {
    background: var(--white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.bill-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.bill-item:last-child {
    border-bottom: none;
}

.bill-item:hover {
    background: var(--light-bg);
    cursor: pointer;
}

/* Recent Section */
.recent-section {
    background: var(--white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
}

.recent-section h2 {
    margin-bottom: 1.5rem;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 10px;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.3s ease;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--white);
    border-radius: 12px;
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.3s ease;
}

.modal-content.modal-large {
    max-width: 900px;
}

@keyframes slideUp {
    from {
        transform: translateY(50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 2px solid var(--light-bg);
}

.modal-header h2 {
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 10px;
}

.close-btn {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-light);
    transition: all 0.3s ease;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.close-btn:hover {
    background: var(--light-bg);
    color: var(--text-dark);
}

.modal-content form {
    padding: 1.5rem;
}

/* Bill Detail */
.bill-detail {
    padding: 1.5rem;
}

.bill-detail-header {
    text-align: center;
    padding: 2rem;
    background: var(--light-bg);
    border-radius: 8px;
    margin-bottom: 2rem;
}

.bill-detail-header h3 {
    font-size: 1.5rem;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.bill-detail-section {
    margin-bottom: 2rem;
}

.bill-detail-section h4 {
    margin-bottom: 1rem;
    color: var(--text-dark);
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
}

.detail-row {
    display: flex;
    justify-content: space-between;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

.detail-row:last-child {
    border-bottom: none;
}

.detail-total {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-color);
    background: var(--light-bg);
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 9999;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.spinner {
    width: 60px;
    height: 60px;
    border: 5px solid rgba(255, 255, 255, 0.3);
    border-top-color: var(--white);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.loading-overlay p {
    color: var(--white);
    font-size: 1.2rem;
    margin-top: 1rem;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-light);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state p {
    font-size: 1.2rem;
}

/* Print Styles */
@media print {
    body {
        background: white;
    }
    
    .header,
    .nav-menu,
    .btn,
    .card-actions {
        display: none !important;
    }
    
    .main-content {
        padding: 0;
    }
    
    .bill-detail {
        box-shadow: none;
    }
}

/* Responsive Design */
@media (max-width: 1024px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .cards-grid {
        grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    }
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-menu {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .nav-item {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .page-title {
        font-size: 1.5rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .history-card {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .history-amount {
        text-align: center;
    }
    
    .page-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
    
    .filter-tabs {
        flex-wrap: wrap;
    }
    
    .modal-content {
        width: 95%;
        max-height: 95vh;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 10px;
    }
    
    .logo {
        font-size: 1.2rem;
    }
    
    .logo i {
        font-size: 1.5rem;
    }
    
    .nav-item span {
        display: none;
    }
    
    .stat-card {
        padding: 1rem;
    }
    
    .stat-icon {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }
    
    .stat-info h3 {
        font-size: 1.5rem;
    }
    
    .btn {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }
    
    .amount-value {
        font-size: 1.5rem;
    }
}