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

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
}

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

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.summary-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.card h3 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.card .amount {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
}

.card .amount.paid {
    color: var(--success-color);
}

.card .amount.remaining {
    color: var(--danger-color);
}

.main-content {
    display: grid;
    gap: 2rem;
}

.add-debt-section,
.debts-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.add-debt-section h2,
.debts-section h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.form-grid {
    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;
}

.form-group.full-width {
    grid-column: 1 / -1;
}

.form-group label {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.2s;
    font-family: inherit;
}

.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(37, 99, 235, 0.1);
}

.form-actions {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    background: var(--text-primary);
}

.btn-success {
    background: var(--success-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-warning {
    background: var(--warning-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Debts Table */
.debts-table-wrapper {
    overflow-x: auto;
    background: var(--card-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.debts-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.debts-table thead {
    background: var(--bg-color);
    position: sticky;
    top: 0;
    z-index: 10;
}

.debts-table th {
    padding: 1rem 0.75rem;
    text-align: left;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 0.75rem;
    border-bottom: 2px solid var(--border-color);
    white-space: nowrap;
}

.debts-table td {
    padding: 1rem 0.75rem;
    border-bottom: 1px solid var(--border-color);
    vertical-align: middle;
}

.debts-table tbody tr {
    transition: background 0.2s;
}

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

.debts-table tbody tr.paid-off-row {
    opacity: 0.6;
    background: #f0fdf4;
}

.debts-table tbody tr.warning-row {
    background: #fef2f2;
}

.warning-badge {
    display: inline-block;
    background: var(--danger-color);
    color: white;
    padding: 0.125rem 0.5rem;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 600;
    margin-top: 0.25rem;
}

.progress-bar-mini {
    width: 80px;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 0.25rem;
}

.progress-fill-mini {
    height: 100%;
    background: var(--success-color);
    transition: width 0.3s ease;
}

.actions-cell {
    white-space: nowrap;
}

.btn-icon {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0.25rem;
    margin: 0 0.125rem;
    transition: transform 0.2s;
}

.btn-icon:hover {
    transform: scale(1.2);
}

.payment-schedule-row {
    background: var(--bg-color) !important;
}

.payments-list-inline {
    padding: 1rem;
    max-height: 400px;
    overflow-y: auto;
}

.debt-card {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.debt-card.paid-off {
    opacity: 0.7;
    background: #f0fdf4;
    border-color: var(--success-color);
}

.debt-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.debt-title {
    flex: 1;
}

.debt-title h3 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.debt-reference {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.debt-actions {
    display: flex;
    gap: 0.5rem;
}

.debt-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.info-item {
    display: flex;
    flex-direction: column;
}

.info-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.25rem;
}

.info-value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1.5rem;
}

.progress-fill {
    height: 100%;
    background: var(--success-color);
    transition: width 0.3s ease;
}

.warning-message {
    background: #fef2f2;
    border: 2px solid var(--danger-color);
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 1.5rem;
    color: #991b1b;
    font-size: 0.875rem;
    line-height: 1.5;
}

.warning-message strong {
    color: var(--danger-color);
    font-weight: 700;
}

.payments-section {
    margin-top: 1rem;
}

.payments-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.payments-header h4 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.toggle-payments {
    background: none;
    border: none;
    color: var(--primary-color);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.875rem;
    padding: 0.5rem;
}

.toggle-payments:hover {
    text-decoration: underline;
}

.payments-list {
    display: none;
    max-height: 400px;
    overflow-y: auto;
}

.payments-list.show {
    display: block;
}

.payment-item {
    display: flex;
    align-items: center;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 0.5rem;
    background: var(--card-bg);
}

.payment-item.paid {
    background: #f0fdf4;
    border-color: var(--success-color);
}

.payment-checkbox {
    width: 20px;
    height: 20px;
    margin-right: 1rem;
    cursor: pointer;
}

.payment-details {
    flex: 1;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.payment-date {
    font-weight: 600;
    color: var(--text-primary);
}

.payment-amount {
    font-weight: 700;
    color: var(--success-color);
}

.payment-balance {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.notes-section {
    margin-top: 1rem;
    padding: 1rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

.notes-section h5 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.notes-section p {
    color: var(--text-primary);
    font-size: 0.875rem;
}

/* Calendar Section */
.calendar-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    margin-bottom: 2rem;
}

.calendar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.calendar-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0;
}

.calendar-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.calendar-month {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    min-width: 150px;
    text-align: center;
}

.btn-nav {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    width: 40px;
    height: 40px;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.calendar-legend {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.legend-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    display: inline-block;
}

.legend-dot.upcoming {
    background: var(--primary-color);
}

.legend-dot.due-soon {
    background: var(--warning-color);
}

.legend-dot.overdue {
    background: var(--danger-color);
}

.legend-dot.paid {
    background: var(--success-color);
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    background: var(--border-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
}

.calendar-day-header {
    background: var(--bg-color);
    padding: 0.75rem;
    text-align: center;
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.calendar-day {
    background: var(--card-bg);
    padding: 0.5rem;
    min-height: 100px;
    position: relative;
    cursor: pointer;
    transition: background 0.2s;
}

.calendar-day:hover {
    background: var(--bg-color);
}

.calendar-day.other-month {
    background: #fafafa;
    opacity: 0.5;
}

.calendar-day.today {
    background: #eff6ff;
    border: 2px solid var(--primary-color);
}

.calendar-day-number {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.calendar-day.other-month .calendar-day-number {
    color: var(--text-secondary);
}

.calendar-payments {
    display: flex;
    flex-direction: column;
    gap: 2px;
    margin-top: 0.25rem;
}

.calendar-payment-dot {
    width: 100%;
    height: 4px;
    border-radius: 2px;
    margin: 1px 0;
}

.calendar-payment-dot.upcoming {
    background: var(--primary-color);
}

.calendar-payment-dot.due-soon {
    background: var(--warning-color);
}

.calendar-payment-dot.overdue {
    background: var(--danger-color);
    animation: pulse 2s infinite;
}

.calendar-payment-dot.paid {
    background: var(--success-color);
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.calendar-details {
    margin-top: 1.5rem;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 8px;
    display: none;
}

.calendar-details.show {
    display: block;
}

.calendar-details h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.calendar-payment-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 0.5rem;
}

.calendar-payment-item.overdue {
    border-color: var(--danger-color);
    background: #fef2f2;
}

.calendar-payment-item.due-soon {
    border-color: var(--warning-color);
    background: #fffbeb;
}

.calendar-payment-item.paid {
    border-color: var(--success-color);
    background: #f0fdf4;
    opacity: 0.7;
}

.calendar-payment-info {
    flex: 1;
}

.calendar-payment-debt {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.calendar-payment-amount {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.calendar-payment-status {
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.calendar-payment-status.overdue {
    background: var(--danger-color);
    color: white;
}

.calendar-payment-status.due-soon {
    background: var(--warning-color);
    color: white;
}

.calendar-payment-status.upcoming {
    background: var(--primary-color);
    color: white;
}

.calendar-payment-status.paid {
    background: var(--success-color);
    color: white;
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .summary-cards {
        grid-template-columns: 1fr;
    }
    
    .form-grid {
        grid-template-columns: 1fr;
    }
    
    .debt-header {
        flex-direction: column;
    }
    
    .debt-actions {
        width: 100%;
        justify-content: flex-start;
    }
    
    .calendar-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .calendar-controls {
        width: 100%;
        justify-content: space-between;
    }
    
    .calendar-day {
        min-height: 80px;
        padding: 0.25rem;
    }
    
    .calendar-day-number {
        font-size: 0.75rem;
    }
    
    .calendar-legend {
        font-size: 0.75rem;
        gap: 1rem;
    }
}