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

:root {
    /* Light mode colors */
    --primary-50: #eff6ff;
    --primary-100: #dbeafe;
    --primary-200: #bfdbfe;
    --primary-300: #93c5fd;
    --primary-400: #60a5fa;
    --primary-500: #3b82f6;
    --primary-600: #2563eb;
    --primary-700: #1d4ed8;
    --primary-800: #1e40af;
    --primary-900: #1e3a8a;
    
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    --green-50: #f0fdf4;
    --green-100: #dcfce7;
    --green-500: #22c55e;
    --green-600: #16a34a;
    
    --red-50: #fef2f2;
    --red-100: #fee2e2;
    --red-500: #ef4444;
    --red-600: #dc2626;
    
    --yellow-50: #fffbeb;
    --yellow-100: #fef3c7;
    --yellow-500: #f59e0b;
    --yellow-600: #d97706;
    
    /* Theme variables (will be overridden in dark mode) */
    --bg-primary: var(--gray-50);
    --bg-secondary: #ffffff;
    --bg-tertiary: var(--gray-100);
    --text-primary: var(--gray-900);
    --text-secondary: var(--gray-600);
    --text-tertiary: var(--gray-500);
    --border-primary: var(--gray-200);
    --border-secondary: var(--gray-300);
    --shadow-color: rgba(0, 0, 0, 0.1);
    --shadow-color-lg: rgba(0, 0, 0, 0.1);
    
    /* Spacing */
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 var(--shadow-color);
    --shadow: 0 1px 3px 0 var(--shadow-color), 0 1px 2px -1px var(--shadow-color);
    --shadow-md: 0 4px 6px -1px var(--shadow-color), 0 2px 4px -2px var(--shadow-color);
    --shadow-lg: 0 10px 15px -3px var(--shadow-color-lg), 0 4px 6px -4px var(--shadow-color-lg);
    --shadow-xl: 0 20px 25px -5px var(--shadow-color-lg), 0 8px 10px -6px var(--shadow-color-lg);
    
    /* Border Radius */
    --radius-sm: 0.125rem;
    --radius: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
}

/* Dark mode color overrides */
[data-theme="dark"] {
    --bg-primary: var(--gray-900);
    --bg-secondary: var(--gray-800);
    --bg-tertiary: var(--gray-700);
    --text-primary: var(--gray-100);
    --text-secondary: var(--gray-300);
    --text-tertiary: var(--gray-400);
    --border-primary: var(--gray-700);
    --border-secondary: var(--gray-600);
    --shadow-color: rgba(0, 0, 0, 0.3);
    --shadow-color-lg: rgba(0, 0, 0, 0.4);
    
    /* Adjust primary colors for better contrast in dark mode */
    --primary-600: #3b82f6;
    --primary-700: #60a5fa;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-4);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-6);
    }
}

/* Header */
.header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-primary);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-4) 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-600);
}

.logo-icon {
    font-size: var(--font-size-2xl);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.theme-toggle:hover {
    background: var(--border-primary);
    color: var(--text-primary);
    transform: translateY(-1px);
}

.theme-icon {
    position: absolute;
    transition: all var(--transition-normal);
}

.theme-icon-light {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.theme-icon-dark {
    opacity: 0;
    transform: rotate(90deg) scale(0.8);
}

[data-theme="dark"] .theme-icon-light {
    opacity: 0;
    transform: rotate(-90deg) scale(0.8);
}

[data-theme="dark"] .theme-icon-dark {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.nav {
    display: flex;
    gap: var(--spacing-2);
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-2) var(--spacing-3);
    background: none;
    border: none;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.nav-btn:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.nav-btn.active {
    background: var(--primary-50);
    color: var(--primary-700);
}

[data-theme="dark"] .nav-btn.active {
    background: var(--primary-900);
    color: var(--primary-300);
}

.nav-btn span {
    display: none;
}

@media (min-width: 640px) {
    .nav-btn span {
        display: inline;
    }
}

/* Main Content */
.main {
    padding: var(--spacing-6) 0 var(--spacing-16);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Search Section */
.search-section {
    margin-bottom: var(--spacing-8);
}

.search-header {
    text-align: center;
    margin-bottom: var(--spacing-6);
}

.search-header h2 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-2);
}

.search-header p {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
}

/* Postal Code Notice */
.postal-code-notice {
    margin: var(--spacing-4) auto 0;
    max-width: 600px;
    background: var(--yellow-50);
    border: 1px solid var(--yellow-500);
    border-radius: var(--radius-lg);
    padding: var(--spacing-3);
    animation: slideDown 0.3s ease-out;
}

[data-theme="dark"] .postal-code-notice {
    background: rgba(245, 158, 11, 0.1);
    border-color: rgba(245, 158, 11, 0.3);
}

.notice-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    flex-wrap: wrap;
}

.notice-content svg {
    color: var(--yellow-500);
    flex-shrink: 0;
}

.notice-content span {
    flex: 1;
    min-width: 200px;
    font-size: var(--font-size-sm);
    color: var(--text-primary);
    font-weight: 500;
}

.notice-action {
    background: var(--yellow-500);
    color: #fff;
    border: none;
    padding: var(--spacing-1) var(--spacing-3);
    border-radius: var(--radius);
    font-size: var(--font-size-xs);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

.notice-action:hover {
    background: var(--yellow-600);
    transform: translateY(-1px);
}

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

.search-form {
    max-width: 600px;
    margin: 0 auto;
}

.search-input-group {
    position: relative;
    margin-bottom: var(--spacing-4);
}

.search-input {
    width: 100%;
    padding: var(--spacing-4);
    padding-right: 3.5rem;
    font-size: var(--font-size-lg);
    border: 2px solid var(--border-primary);
    border-radius: var(--radius-xl);
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: all var(--transition-fast);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px var(--primary-100);
}

[data-theme="dark"] .search-input:focus {
    box-shadow: 0 0 0 3px var(--primary-900);
}

.search-input::placeholder {
    color: var(--text-tertiary);
}

.search-button {
    position: absolute;
    right: var(--spacing-2);
    top: 50%;
    transform: translateY(-50%);
    width: 2.5rem;
    height: 2.5rem;
    background: var(--primary-600);
    border: none;
    border-radius: var(--radius-lg);
    color: #fff;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.search-button:hover {
    background: var(--primary-700);
}

.filters {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3);
}

@media (min-width: 640px) {
    .filters {
        grid-template-columns: 1fr 1fr;
    }
}

.filter-select {
    padding: var(--spacing-3);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.filter-select:focus {
    outline: none;
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px var(--primary-100);
}

[data-theme="dark"] .filter-select:focus {
    box-shadow: 0 0 0 3px var(--primary-900);
}

/* Results Grid */
.results-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-4);
}

@media (min-width: 640px) {
    .results-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .results-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* Product Card */
.product-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-5);
    box-shadow: var(--shadow);
    transition: all var(--transition-normal);
    border: 1px solid var(--border-primary);
    position: relative;
    overflow: hidden;
}

.product-card:hover {
    box-shadow: var(--shadow-lg);
}

.product-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--spacing-4);
}

.product-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.4;
    flex: 1;
    margin-right: var(--spacing-2);
}

.favorite-btn {
    background: none;
    border: none;
    padding: var(--spacing-1);
    cursor: pointer;
    color: var(--text-tertiary);
    transition: all var(--transition-fast);
    border-radius: var(--radius);
}

.favorite-btn:hover {
    color: var(--yellow-500);
    background: var(--yellow-50);
}

[data-theme="dark"] .favorite-btn:hover {
    background: rgba(245, 158, 11, 0.1);
}

.favorite-btn.active {
    color: var(--yellow-500);
}

.product-image {
    width: 100%;
    height: 120px;
    object-fit: cover;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-4);
    background: var(--bg-tertiary);
}

.product-prices {
    margin-bottom: var(--spacing-4);
}

.price-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-2) 0;
    border-bottom: 1px solid var(--border-primary);
}

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

.store-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
}

.store-logo {
    width: 24px;
    height: 24px;
    border-radius: var(--radius);
    background: var(--border-primary);
}

.store-name {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--text-primary);
}

.price-value {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
}

.current-price {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--text-primary);
}

.original-price {
    font-size: var(--font-size-sm);
    color: var(--text-tertiary);
    text-decoration: line-through;
}

.price-change {
    font-size: var(--font-size-xs);
    font-weight: 500;
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--radius);
}

.price-change.decrease {
    background: var(--green-100);
    color: var(--green-600);
}

.price-change.increase {
    background: var(--red-100);
    color: var(--red-600);
}

.best-price-badge {
    position: absolute;
    top: var(--spacing-3);
    right: var(--spacing-3);
    background: var(--green-500);
    color: #fff;
    font-size: var(--font-size-xs);
    font-weight: 600;
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--radius);
    text-transform: uppercase;
    letter-spacing: 0.025em;
}

/* Empty States */
.empty-state {
    text-align: center;
    padding: var(--spacing-12) var(--spacing-4);
    grid-column: 1 / -1;
}

.empty-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-4);
    opacity: 0.5;
}

.empty-state h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-2);
}

.empty-state p {
    color: var(--text-secondary);
    max-width: 400px;
    margin: 0 auto;
}

/* Loading State */
.loading-state {
    text-align: center;
    padding: var(--spacing-8);
    grid-column: 1 / -1;
}

.loading-state.hidden {
    display: none;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-primary);
    border-top-color: var(--primary-600);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--spacing-4);
}

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

/* Settings */
.settings-header, .favorites-header {
    text-align: center;
    margin-bottom: var(--spacing-8);
}

.settings-header h2, .favorites-header h2 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-2);
}

.settings-header p, .favorites-header p {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
}

.settings-grid {
    display: grid;
    gap: var(--spacing-6);
    max-width: 800px;
    margin: 0 auto;
}

.settings-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-primary);
}

.settings-card h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-4);
}

.setting-item {
    margin-bottom: var(--spacing-4);
}

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

.setting-item label {
    display: block;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--spacing-2);
}

.setting-item input[type="text"],
.setting-item input[type="number"] {
    width: 100%;
    padding: var(--spacing-3);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: var(--font-size-base);
    transition: all var(--transition-fast);
}

.setting-item input[type="text"]:focus,
.setting-item input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px var(--primary-100);
}

[data-theme="dark"] .setting-item input[type="text"]:focus,
[data-theme="dark"] .setting-item input[type="number"]:focus {
    box-shadow: 0 0 0 3px var(--primary-900);
}

.setting-item input[type="text"]::placeholder,
.setting-item input[type="number"]::placeholder {
    color: var(--text-tertiary);
}

.setting-item small {
    display: block;
    font-size: var(--font-size-sm);
    color: var(--text-tertiary);
    margin-top: var(--spacing-1);
}

/* Toggle Switch */
.toggle-label {
    display: flex !important;
    align-items: center;
    gap: var(--spacing-3);
    cursor: pointer;
    margin-bottom: var(--spacing-2) !important;
}

.toggle-label input[type="checkbox"] {
    display: none;
}

.toggle-slider {
    position: relative;
    width: 48px;
    height: 24px;
    background: var(--border-secondary);
    border-radius: 12px;
    transition: all var(--transition-fast);
}

.toggle-slider::before {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 20px;
    height: 20px;
    background: var(--bg-secondary);
    border-radius: 50%;
    transition: all var(--transition-fast);
}

.toggle-label input[type="checkbox"]:checked + .toggle-slider {
    background: var(--primary-600);
}

.toggle-label input[type="checkbox"]:checked + .toggle-slider::before {
    transform: translateX(24px);
}

/* Input with Unit */
.input-with-unit {
    position: relative;
}

.input-with-unit input {
    padding-right: 3rem;
}

.unit {
    position: absolute;
    right: var(--spacing-3);
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-tertiary);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

/* Checkbox Grid */
.checkbox-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-2);
    margin-top: var(--spacing-2);
}

.checkbox-label {
    display: flex !important;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-2);
    border-radius: var(--radius);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-bottom: 0 !important;
}

.checkbox-label:hover {
    background: var(--bg-tertiary);
}

.checkbox-label input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: var(--primary-600);
}

.checkbox-label span {
    font-size: var(--font-size-sm);
    color: var(--text-primary);
}

/* Install Button */
.install-button {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    width: 100%;
    padding: var(--spacing-3);
    background: var(--primary-600);
    color: #fff;
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.install-button:hover {
    background: var(--primary-700);
}

.pwa-status {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    color: var(--green-600);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--spacing-4);
    animation: fadeIn 0.3s ease-out;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    max-width: 400px;
    width: 100%;
    text-align: center;
    border: 1px solid var(--border-primary);
    animation: slideUp 0.3s ease-out;
}

.modal-content h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-3);
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-5);
    line-height: 1.6;
}

.modal-content ol {
    color: var(--text-secondary);
    line-height: 1.6;
    padding-left: var(--spacing-5);
}

.modal-content ol li {
    margin-bottom: var(--spacing-2);
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-actions {
    display: flex;
    gap: var(--spacing-3);
}

/* Buttons */
.btn {
    flex: 1;
    padding: var(--spacing-3);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-primary {
    background: var(--primary-600);
    color: #fff;
}

.btn-primary:hover {
    background: var(--primary-700);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

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

/* Utilities */
.hidden {
    display: none !important;
}

/* Responsive Adjustments */
@media (max-width: 640px) {
    .container {
        padding: 0 var(--spacing-3);
    }
    
    .header-content {
        padding: var(--spacing-3) 0;
    }
    
    .logo {
        font-size: var(--font-size-lg);
    }
    
    .search-header h2 {
        font-size: var(--font-size-2xl);
    }
    
    .search-header p {
        font-size: var(--font-size-base);
    }
    
    .filters {
        grid-template-columns: 1fr;
    }
    
    .checkbox-grid {
        grid-template-columns: 1fr;
    }
    
    .modal-actions {
        flex-direction: column;
    }
}

/* Animation for card entrance */
@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.product-card {
    animation: slideUp 0.3s ease-out;
}

/* Focus styles for accessibility */
*:focus {
    outline: 2px solid var(--primary-500);
    outline-offset: 2px;
}

button:focus,
input:focus,
select:focus {
    outline: none;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --gray-300: #000;
        --gray-600: #000;
        --gray-700: #000;
        --gray-900: #000;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    
    .spinner {
        animation: none;
    }
}