:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --card-bg: #ffffff;
    --accent-color: #dc2626;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #0f172a;
        --bg-secondary: #1e293b;
        --text-primary: #f1f5f9;
        --text-secondary: #94a3b8;
        --border-color: #334155;
        --card-bg: #1e293b;
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.5;
}

.app {
    max-width: 480px;
    margin: 0 auto;
    min-height: 100vh;
    background: var(--bg-primary);
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
}

/* Header */
.header {
    background: linear-gradient(135deg, #dc2626, #ef4444);
    color: white;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

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

.btn-icon {
    background: rgba(255,255,255,0.2);
    border: none;
    color: white;
    width: 44px;
    height: 44px;
    border-radius: 12px;
    font-size: 1.2rem;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-icon:hover {
    background: rgba(255,255,255,0.3);
}

/* Main Content */
.main {
    padding: 0.75rem;
    padding-bottom: 1.5rem;
}

/* Quick Add Card */
.quick-add-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.amount-input {
    display: flex;
    align-items: center;
    margin-bottom: 1rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    padding: 0.5rem;
}

.currency {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--accent-color);
    margin-right: 0.5rem;
}

#amountInput {
    flex: 1;
    border: none;
    background: none;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    outline: none;
}

#amountInput::placeholder {
    color: var(--text-secondary);
}

/* Categories Grid */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.category-btn {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem 0.5rem;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.category-btn:hover {
    border-color: var(--accent-color);
    background: rgba(220, 38, 38, 0.1);
}

.category-btn.selected {
    border-color: var(--accent-color);
    background: rgba(220, 38, 38, 0.1);
}

.category-icon {
    font-size: 1.5rem;
}

.category-name {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-primary);
    text-align: center;
}

/* Expense Details */
.expense-details {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.expense-details input {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--card-bg);
    color: var(--text-primary);
}

.expense-details input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

.detail-actions {
    display: flex;
    gap: 0.75rem;
}

.btn-primary {
    background: var(--accent-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
    flex: 1;
}

.btn-primary:hover {
    background: #b91c1c;
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
    flex: 1;
}

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

/* Overview Section */
.overview-section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    margin-bottom: 1.5rem;
    overflow: hidden;
}

.overview-toggle {
    width: 100%;
    background: none;
    border: none;
    padding: 1rem;
    display: flex;
    align-items: center;
    cursor: pointer;
    color: var(--text-primary);
    transition: background 0.2s;
}

.overview-toggle:hover {
    background: var(--bg-secondary);
}

.overview-icon {
    font-size: 1.5rem;
    margin-right: 0.75rem;
}

.overview-text {
    flex: 1;
    text-align: left;
    font-weight: 600;
    font-size: 1.1rem;
}

.overview-arrow {
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: transform 0.2s;
}

.overview-arrow.rotated {
    transform: rotate(180deg);
}

.overview-content {
    padding: 0 1rem 1rem;
    border-top: 1px solid var(--border-color);
}

.pie-chart-container {
    min-height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 1rem 0;
}

.category-details {
    margin-top: 1rem;
}

.category-detail-item {
    display: flex;
    align-items: center;
    padding: 0.75rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    margin-bottom: 0.5rem;
    cursor: pointer;
    transition: background 0.2s;
}

.category-detail-item:hover {
    background: var(--border-color);
}

.view-all-btn {
    width: 100%;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.75rem;
    border-radius: 8px;
    cursor: pointer;
    margin-top: 0.5rem;
    transition: background 0.2s;
}

.view-all-btn:hover {
    background: var(--border-color);
}

.modal-content.large {
    max-width: 500px;
    max-height: 80vh;
}

.all-expenses-list {
    max-height: 60vh;
    overflow-y: auto;
}

.export-options {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.export-option-btn {
    display: flex;
    align-items: center;
    padding: 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
}

.export-option-btn:hover {
    border-color: var(--accent-color);
    background: rgba(220, 38, 38, 0.1);
}

.export-icon {
    font-size: 2rem;
    margin-right: 1rem;
}

.export-title {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.export-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Chart Section */
.chart-section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    margin-bottom: 1.5rem;
}

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

.chart-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.chart-controls {
    display: flex;
    gap: 0.25rem;
    background: var(--bg-secondary);
    border-radius: 6px;
    padding: 0.25rem;
    margin-bottom: 1rem;
}

.month-selector {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1rem;
    padding: 0.5rem;
    background: var(--bg-secondary);
    border-radius: 8px;
}

.month-nav-btn {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    color: var(--text-primary);
}

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

.month-display {
    font-weight: 600;
    color: var(--text-primary);
    min-width: 120px;
    text-align: center;
}

.chart-btn {
    background: none;
    border: none;
    padding: 0.5rem 0.75rem;
    border-radius: 4px;
    font-size: 0.85rem;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.2s;
}

.chart-btn.active {
    background: var(--accent-color);
    color: white;
}

.chart-container {
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.chart-placeholder {
    color: var(--text-secondary);
    font-style: italic;
}

/* Expenses Section */
.expenses-section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
}

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

.section-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.total-amount {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--accent-color);
}

/* Expense Items */
.expenses-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.expense-icon {
    font-family: system-ui, -apple-system;
    font-variant-emoji: emoji;
}

.expense-item {
    position: relative;
    overflow: hidden;
}

.expense-item.swiping {
    transform: translateX(-80px);
    transition: transform 0.3s ease;
}

.delete-btn {
    position: absolute;
    right: -80px;
    top: 0;
    bottom: 0;
    width: 80px;
    background: #ff4444;
    color: white;
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2em;
    cursor: pointer;
}

.expense-item {
    display: flex;
    align-items: center;
    padding: 0.75rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s;
}

.expense-item:hover {
    background: var(--border-color);
}

.expense-icon {
    font-size: 1.5rem;
    margin-right: 0.75rem;
}

.expense-info {
    flex: 1;
}

.expense-category {
    font-weight: 500;
    color: var(--text-primary);
}

.expense-description {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.expense-date {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-right: 0.75rem;
}

.expense-amount {
    font-weight: 600;
    color: var(--accent-color);
}

.delete-btn {
    background: #ef4444;
    color: white;
    border: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    font-size: 0.75rem;
    cursor: pointer;
    margin-left: 0.5rem;
    opacity: 0;
    transition: opacity 0.2s;
}

.expense-item:hover .delete-btn {
    opacity: 1;
}

.add-category-btn {
    border: 2px dashed var(--border-color) !important;
    background: transparent !important;
}

.add-category-btn:hover {
    border-color: var(--accent-color) !important;
    background: rgba(220, 38, 38, 0.05) !important;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
    padding: 1rem;
}

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

.modal-content {
    background: var(--card-bg);
    border-radius: 16px;
    width: 100%;
    max-width: 400px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 1.5rem 0;
    margin-bottom: 1rem;
}

.modal-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.btn-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-body {
    padding: 0 1.5rem 1.5rem;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--card-bg);
    color: var(--text-primary);
}

.form-group input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

.emoji-picker {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.5rem;
}

.emoji-btn {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 0.75rem;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.2s;
}

.emoji-btn:hover {
    border-color: var(--accent-color);
    background: rgba(220, 38, 38, 0.1);
}

.emoji-btn.selected {
    border-color: var(--accent-color);
    background: rgba(220, 38, 38, 0.1);
}

.form-actions {
    display: flex;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

/* Responsive */
@media (max-width: 480px) {
    .app {
        box-shadow: none;
    }
    
    .main {
        padding: 0.5rem;
    }
    
    .categories-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.sync-status {
    background: var(--bg-secondary);
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 1rem;
}

.status-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.status-item:last-child {
    margin-bottom: 0;
}

.form-help {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.sync-actions {
    display: flex;
    gap: 0.75rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.sync-actions button {
    flex: 1;
}