/* ===================================
   HPro - Main Styles
   Modern HVAC Product Resource
   =================================== */

/* CSS Variables */
:root {
    /* Colors - Dark Professional HVAC Theme */
    --primary-blue: #00a8e8;
    --primary-dark: #0077b6;
    --primary-light: #48cae4;
    
    --secondary-steel: #90e0ef;
    --secondary-light: #ade8f4;
    
    --accent-orange: #ff6b35;
    --accent-green: #06ffa5;
    
    /* Dark Theme Colors */
    --neutral-50: #1a1a1a;
    --neutral-100: #242424;
    --neutral-200: #2e2e2e;
    --neutral-300: #3a3a3a;
    --neutral-400: #525252;
    --neutral-500: #737373;
    --neutral-600: #a3a3a3;
    --neutral-700: #d4d4d4;
    --neutral-800: #e5e5e5;
    --neutral-900: #f5f5f5;
    
    --white: #ffffff;
    --black: #000000;
    
    /* Dark Theme Specific */
    --bg-primary: #0a0a0a;
    --bg-secondary: #141414;
    --bg-tertiary: #1f1f1f;
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --border-color: #2e2e2e;
    
    /* Typography */
    --font-display: 'Archivo', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-body: 'Work Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;
}

/* ===================================
   Reset & Base Styles
   =================================== */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-dark);
}

/* ===================================
   Header
   =================================== */

.main-header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

.header-container {
    max-width: 2000px;
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-xl);
    height: 80px;
}

.logo {
    display: flex;
    align-items: center;
}

.logo h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-blue);
    letter-spacing: -0.02em;
}

.logo a {
    text-decoration: none;
}

.logo a:hover h1 {
    color: var(--primary-light);
}

/* Header Actions */
.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

/* Back to Start Page Button */
.btn-back-to-start {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-lg);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-fast);
}

.btn-back-to-start:hover {
    border-color: var(--primary-blue);
    color: var(--text-primary);
    background: rgba(0, 168, 232, 0.1);
}

.btn-back-to-start svg {
    width: 18px;
    height: 18px;
}

.search-container {
    position: relative;
    width: 280px;
}

.search-input {
    width: 100%;
    padding: 0.625rem 1rem 0.625rem 2.5rem;
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-lg);
    font-size: 0.95rem;
    font-family: var(--font-body);
    color: var(--text-primary);
    background: var(--bg-tertiary);
    transition: all var(--transition-fast);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(0, 168, 232, 0.2);
}

.search-input::placeholder {
    color: var(--neutral-500);
}

.search-icon {
    position: absolute;
    left: 0.875rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--neutral-500);
    pointer-events: none;
}

/* ===================================
   Product Series Navigation (Top Tabs)
   =================================== */

.product-series-nav {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 80px;
    z-index: 99;
}

.product-series-container {
    max-width: 2000px;
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
}

.product-series-tabs {
    display: flex;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) 0;
    overflow-x: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--neutral-400) transparent;
}

.product-series-tabs::-webkit-scrollbar {
    height: 6px;
}

.product-series-tabs::-webkit-scrollbar-track {
    background: transparent;
}

.product-series-tabs::-webkit-scrollbar-thumb {
    background: var(--neutral-400);
    border-radius: 3px;
}

.series-tab {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--bg-tertiary);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-lg);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    flex-shrink: 0;
}

.series-tab:hover {
    border-color: var(--primary-blue);
    color: var(--text-primary);
    background: rgba(0, 168, 232, 0.1);
}

.series-tab.active {
    background: var(--primary-blue);
    border-color: var(--primary-blue);
    color: var(--black);
}

.series-tab .count {
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.125rem 0.5rem;
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-sm);
}

.series-tab.active .count {
    background: rgba(0, 0, 0, 0.3);
    color: var(--black);
}

/* "All Products" tab special styling */
.series-tab.all-products {
    background: transparent;
    border-style: dashed;
}

.series-tab.all-products:hover {
    background: rgba(0, 168, 232, 0.1);
    border-style: solid;
}

.series-tab.all-products.active {
    background: var(--primary-blue);
    border-style: solid;
}

/* ===================================
   Main Content Layout
   =================================== */

.main-content {
    max-width: 2000px;
    margin: 0 auto;
    padding: var(--spacing-2xl) var(--spacing-xl);
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--spacing-2xl);
    align-items: start;
}

/* ===================================
   Filters Sidebar - UPDATED WITH SCROLLING
   =================================== */

.filters-sidebar {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    position: sticky;
    top: 160px; /* Adjusted for header + series nav */
    border: 1px solid var(--border-color);
    
    /* NEW: Enable independent scrolling */
    max-height: calc(100vh - 180px);
    overflow-y: auto;
    overflow-x: hidden;
}

/* Custom scrollbar styling for filter sidebar */
.filters-sidebar::-webkit-scrollbar {
    width: 8px;
}

.filters-sidebar::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
}

.filters-sidebar::-webkit-scrollbar-thumb {
    background: var(--neutral-400);
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
}

.filters-sidebar::-webkit-scrollbar-thumb:hover {
    background: var(--neutral-500);
}

/* Firefox scrollbar styling */
.filters-sidebar {
    scrollbar-width: thin;
    scrollbar-color: var(--neutral-400) var(--bg-tertiary);
}

/* Reset Button - AT TOP */
.btn-reset {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-bottom: var(--spacing-lg);
}

.btn-reset:hover {
    background: var(--neutral-200);
    color: var(--text-primary);
    border-color: var(--primary-blue);
}

.filter-section {
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
}

.filter-section:last-of-type {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

/* Hide empty filter sections */
.filter-section.hidden {
    display: none;
}

.filter-title {
    font-size: 0.875rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.filter-options {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.filter-option {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.5rem var(--spacing-md);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 0.95rem;
    white-space: nowrap;
}

.filter-option:hover {
    background: var(--bg-tertiary);
}

/* Hide the checkbox */
.filter-option input[type="checkbox"] {
    display: none;
}

/* Style the label when active */
.filter-option.active {
    background: var(--primary-blue);
}

.filter-option.active span {
    color: var(--black);
    font-weight: 600;
}

.filter-option.active .count {
    color: rgba(0, 0, 0, 0.7);
}

.filter-option span {
    color: var(--text-secondary);
}

.filter-option span:first-of-type {
    flex: 1;
}

.filter-option .count {
    font-size: 0.8rem;
    color: var(--neutral-500);
    font-weight: 600;
    margin-left: auto;
}

/* ===================================
   Products Section
   =================================== */

.products-section {
    min-height: 600px;
}

.products-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--border-color);
}

.results-info h2 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

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

/* View Controls */
.view-controls {
    display: flex;
    gap: var(--spacing-xs);
    background: var(--bg-tertiary);
    padding: 0.25rem;
    border-radius: var(--radius-md);
}

.view-btn {
    padding: var(--spacing-sm);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.view-btn:hover {
    color: var(--text-primary);
}

.view-btn.active {
    background: var(--bg-secondary);
    color: var(--primary-blue);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* ===================================
   Loading & Empty States
   =================================== */

.loading-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-3xl) var(--spacing-xl);
    gap: var(--spacing-lg);
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-blue);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.loading-state p {
    color: var(--text-secondary);
    font-size: 1rem;
}

.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-3xl) var(--spacing-xl);
    text-align: center;
    gap: var(--spacing-md);
}

.empty-state svg {
    color: var(--neutral-400);
    margin-bottom: var(--spacing-md);
}

.empty-state h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

.empty-state p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* ===================================
   Utility Classes
   =================================== */

.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}