/* Reset and base styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    /* Colors */
    --color-bg: #F5F0E6;
    --color-receipt: #FFFEF7;
    --color-text: #2C2C2C;
    --color-text-light: #666;
    --color-border: #E0DCD4;
    --color-accent: #4A90A4;
    --color-accent-hover: #3A7A94;
    --color-secondary: #6B7280;
    --color-secondary-hover: #4B5563;
    --color-delete: #E74C3C;
    --color-delete-hover: #C0392B;
    --color-add: #27AE60;
    --color-add-hover: #219A52;

    /* Typography */
    --font-ui: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-receipt: 'Courier New', Courier, monospace;

    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;

    /* Transitions */
    --transition-speed: 0.2s;

    /* Border radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
}

html {
    font-size: 16px;
}

body {
    font-family: var(--font-ui);
    background-color: var(--color-bg);
    color: var(--color-text);
    min-height: 100vh;
    min-height: 100dvh;
    line-height: 1.5;
}

/* App container */
.app {
    max-width: 480px;
    margin: 0 auto;
    padding: var(--spacing-md);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    min-height: 100dvh;
}

/* Header */
.header {
    text-align: center;
    padding: var(--spacing-md) 0;
}

.header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.tagline {
    font-size: 0.875rem;
    color: var(--color-text-light);
}

/* Main content */
.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

/* Preview section */
.preview-section {
    display: flex;
    justify-content: center;
}

.canvas-container {
    background: linear-gradient(135deg, #ddd 0%, #eee 100%);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

#receiptCanvas {
    display: block;
    max-width: 100%;
    height: auto;
}

/* Editor section */
.editor-section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.editor-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.editor-group label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-light);
}

.editor-group input {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: var(--font-ui);
    transition: border-color var(--transition-speed);
}

.editor-group input:focus {
    outline: none;
    border-color: var(--color-accent);
}

/* Items section */
.items-section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

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

.items-header label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-light);
}

.btn-add {
    width: 36px;
    height: 36px;
    border: none;
    border-radius: 50%;
    background: var(--color-add);
    color: white;
    font-size: 1.25rem;
    font-weight: bold;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-speed), transform var(--transition-speed);
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
}

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

.btn-add:active {
    transform: scale(0.95);
}

/* Items list */
.items-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.item-row {
    display: grid;
    grid-template-columns: 1fr auto auto;
    gap: var(--spacing-sm);
    align-items: center;
    padding: var(--spacing-sm);
    background: var(--color-bg);
    border-radius: var(--radius-md);
    animation: fadeIn 0.2s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.item-row input {
    padding: var(--spacing-sm);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-family: var(--font-ui);
    min-width: 0;
}

.item-row input:focus {
    outline: none;
    border-color: var(--color-accent);
}

.item-row input.item-desc {
    /* Takes remaining space via grid */
}

.item-row input.item-value {
    width: 80px;
    text-align: right;
}

.btn-delete {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--color-delete);
    font-size: 1.25rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-speed);
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
}

.btn-delete:hover {
    background: rgba(231, 76, 60, 0.1);
}

.empty-message {
    text-align: center;
    color: var(--color-text-light);
    font-size: 0.875rem;
    padding: var(--spacing-md);
    background: var(--color-bg);
    border-radius: var(--radius-md);
    border: 2px dashed var(--color-border);
}

/* Actions section */
.actions-section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    font-family: var(--font-ui);
    cursor: pointer;
    min-height: 48px;
    transition: background-color var(--transition-speed), transform var(--transition-speed);
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
}

.btn:active {
    transform: scale(0.98);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--color-accent-hover);
}

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

.btn-secondary:hover:not(:disabled) {
    background: var(--color-secondary-hover);
}

.btn-icon {
    font-size: 1.25rem;
}

/* Footer */
.footer {
    text-align: center;
    padding: var(--spacing-lg) 0 var(--spacing-md);
    font-size: 0.75rem;
    color: var(--color-text-light);
}

.footer a {
    color: var(--color-accent);
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

/* Responsive adjustments */
@media (min-width: 400px) {
    .actions-section {
        flex-direction: row;
    }

    .actions-section .btn {
        flex: 1;
    }
}

@media (min-width: 768px) {
    .app {
        padding: var(--spacing-xl);
    }

    .header h1 {
        font-size: 1.75rem;
    }

    .canvas-container {
        padding: var(--spacing-lg);
    }
}