:root {
    --color-bg: #f5f6fa;
    --color-surface: #ffffff;
    --color-dark: #1e272e;
    --color-accent: #ff9f43; /* Caution Orange */
    --color-accent-hover: #e17009;
    --color-blue: #2f3640;
    --color-gray: #718093;
    --color-border: #dcdde1;
    
    --font-ui: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-heading: 'Oswald', 'Impact', sans-serif;
    
    --radius-sharp: 4px;
}

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

body {
    background-color: var(--color-bg);
    color: var(--color-dark);
    font-family: var(--font-ui);
    line-height: 1.5;
}

img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 5%; }
.section-padding { padding: clamp(3rem, 8vw, 5rem) 0; }
.page-top { padding-top: clamp(100px, 15vh, 140px); }
.mt-medium { margin-top: 2rem; }
.mt-large { margin-top: 4rem; }
.mb-large { margin-bottom: 3rem; }
.pb-large { padding-bottom: 5rem; }
.text-center { text-align: center; }
.text-white { color: white; }
.text-accent { color: var(--color-accent); }
.text-gray { color: var(--color-gray); }
.bg-dark { background-color: var(--color-dark); }

/* Typography */
h1, h2, h3, h4 { font-family: var(--font-heading); text-transform: uppercase; letter-spacing: 0.5px; }
.section-title { font-size: 2.5rem; border-bottom: 4px solid var(--color-accent); display: inline-block; margin-bottom: 2rem; padding-bottom: 0.5rem; }

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    font-family: var(--font-heading);
    text-transform: uppercase;
    font-size: 1rem;
    border: none;
    background: var(--color-dark);
    color: white;
    cursor: pointer;
    border-radius: var(--radius-sharp);
    transition: background 0.3s;
}
.btn:hover { background: var(--color-blue); }
.btn-block { display: block; width: 100%; text-align: center; }
.btn-outline-light { background: transparent; border: 2px solid white; }
.btn-outline-light:hover { background: white; color: var(--color-dark); }
.btn-accent { background: var(--color-accent); color: var(--color-dark); }
.btn-accent:hover { background: var(--color-accent-hover); }

/* Nav Progress */
.nav-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: var(--color-accent);
    width: 0%;
    z-index: 1000;
}

/* Header */
.site-header {
    background: var(--color-dark);
    color: white;
    padding: 1.5rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.header-inner { display: flex; justify-content: space-between; align-items: center; }
.logo img { height: 35px; filter: brightness(0) invert(1); }
.main-nav { display: flex; gap: 2rem; }
.main-nav a { font-family: var(--font-heading); text-transform: uppercase; font-size: 0.9rem; letter-spacing: 1px; color: #a5b1c2; transition: color 0.3s; }
.main-nav a:hover, .main-nav a.active { color: var(--color-accent); }

/* Hero */
.hero-industrial {
    background: linear-gradient(rgba(30,39,46,0.8), rgba(30,39,46,0.9)), url("https://images.pexels.com/photos/3807329/pexels-photo-3807329.jpeg?auto=compress&cs=tinysrgb&w=1200") center/cover;
    padding: clamp(4rem, 10vh, 8rem) 0;
    color: white;
}
.hero-grid { display: grid; grid-template-columns: 1.5fr 1fr; gap: 4rem; align-items: center; }
.hero-content h1 { font-size: 4rem; line-height: 1.1; margin-bottom: 1rem; }
.hero-content p { font-size: 1.2rem; color: #dcdde1; }
.vehicle-selector { background: var(--color-surface); padding: 2rem; border-top: 5px solid var(--color-accent); border-radius: var(--radius-sharp); color: var(--color-dark); }
.vehicle-selector h3 { margin-bottom: 1.5rem; font-size: 1.5rem; }
.vehicle-selector select { width: 100%; padding: 12px; margin-bottom: 1rem; border: 1px solid var(--color-border); font-family: inherit; border-radius: var(--radius-sharp); }

/* Categories */
.category-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.cat-card { position: relative; background: var(--color-dark); overflow: hidden; border-radius: var(--radius-sharp); display: block; }
.cat-card img { width: 100%; height: 250px; object-fit: cover; opacity: 0.7; transition: opacity 0.3s, transform 0.5s; }
.cat-card:hover img { opacity: 1; transform: scale(1.05); }
.cat-label { position: absolute; bottom: 0; left: 0; width: 100%; padding: 1rem; background: rgba(30,39,46,0.9); color: white; font-family: var(--font-heading); font-size: 1.2rem; display: flex; justify-content: space-between; align-items: center; }
.icon-small { width: 24px; filter: brightness(0) invert(1); }

/* Brands */
.brand-strip { display: flex; justify-content: center; gap: 3rem; flex-wrap: wrap; }
.brand-name { font-family: var(--font-heading); font-size: 2rem; color: #718093; opacity: 0.5; }

/* Promises */
.promises-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; text-align: center; }
.promise-item { background: var(--color-surface); padding: 3rem 2rem; border: 1px solid var(--color-border); border-radius: var(--radius-sharp); }

/* Catalog Page */
.sticky-top { position: sticky; top: 60px; /* adjusted for mobile header */ z-index: 90; background: var(--color-surface); padding: 1rem 0; border-bottom: 1px solid var(--color-border); transition: box-shadow 0.3s; }
.sticky-top.is-pinned { box-shadow: 0 4px 6px rgba(0,0,0,0.05); }
.filter-flex { display: flex; justify-content: space-between; gap: 1rem; }
.search-input { flex-grow: 1; padding: 10px; border: 1px solid var(--color-border); border-radius: var(--radius-sharp); }
.filter-controls { display: flex; gap: 1rem; }
.filter-controls select { padding: 10px; border: 1px solid var(--color-border); border-radius: var(--radius-sharp); }

.catalog-layout { margin-top: 2rem; }
.catalog-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 2rem; }
.part-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sharp);
    overflow: hidden;
    position: relative;
    /* transition for filter */
    transition: opacity 0.3s ease, transform 0.3s ease;
}
.part-card.hidden { display: none; opacity: 0; transform: scale(0.9); }
.part-card img { width: 100%; height: 200px; object-fit: cover; border-bottom: 1px solid var(--color-border); }
.part-info { padding: 1.5rem; }
.part-sku { font-size: 0.8rem; color: var(--color-gray); font-family: monospace; }
.part-price { font-weight: bold; font-size: 1.2rem; margin-top: 0.5rem; color: var(--color-accent-hover); }

/* Card Quick Preview Drawer */
.quick-preview-drawer {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    background: var(--color-dark);
    color: white;
    padding: 1.5rem;
    transform: translateY(100%);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
.part-card:hover .quick-preview-drawer { transform: translateY(0); }
.quick-preview-drawer p { font-size: 0.85rem; border-bottom: 1px solid #3d3d3d; padding-bottom: 5px; margin-bottom: 5px; }

/* Brands Page */
.brand-index-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }
.brand-box { background: var(--color-surface); border: 1px solid var(--color-border); padding: 2rem; border-radius: var(--radius-sharp); text-align: center; }
.brand-link { display: inline-block; margin-top: 1rem; color: var(--color-accent-hover); font-weight: bold; font-size: 0.9rem; }

/* Guide Page */
.guide-layout { display: grid; grid-template-columns: 250px 1fr; gap: 4rem; align-items: start; }
.guide-sidebar { position: sticky; top: 120px; background: var(--color-surface); padding: 1.5rem; border: 1px solid var(--color-border); border-radius: var(--radius-sharp); }
.guide-sidebar ul { list-style: none; }
.guide-sidebar li { margin-bottom: 1rem; }
.guide-sidebar a { font-family: var(--font-heading); color: var(--color-gray); transition: color 0.3s; }
.guide-sidebar a.active { color: var(--color-accent-hover); }
.guide-section { padding-top: 2rem; border-bottom: 1px dashed var(--color-border); padding-bottom: 3rem; }
.tech-box { background: #fff3e0; border-left: 4px solid var(--color-accent); padding: 1rem; margin-top: 1rem; display: flex; align-items: center; gap: 1rem; color: #d35400; font-weight: bold; }
.guide-img { border: 1px solid var(--color-border); border-radius: var(--radius-sharp); }

/* Support & Contact */
.support-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; }
.support-panel { background: var(--color-surface); padding: 3rem; border-top: 4px solid var(--color-dark); border-radius: var(--radius-sharp); }
.support-panel ul { margin-top: 1rem; padding-left: 1.5rem; }
.faq-item { background: var(--color-surface); padding: 1.5rem; margin-bottom: 1rem; border: 1px solid var(--color-border); border-radius: var(--radius-sharp); }

.contact-box { background: var(--color-surface); border-radius: var(--radius-sharp); overflow: hidden; border: 1px solid var(--color-border); }
.contact-header { background: var(--color-dark); padding: 3rem; text-align: center; }
.contact-body { display: grid; grid-template-columns: 1fr 2fr; }
.contact-direct { padding: 3rem; background: #f1f2f6; border-right: 1px solid var(--color-border); }
.accent-email { font-family: var(--font-heading); font-size: 1.5rem; color: var(--color-accent-hover); }
.industrial-form { padding: 3rem; }
.input-row { display: flex; gap: 1rem; margin-bottom: 1rem; }
.industrial-form input, .industrial-form select, .industrial-form textarea { width: 100%; padding: 12px; margin-bottom: 1rem; border: 1px solid var(--color-border); background: var(--color-bg); font-family: inherit; border-radius: var(--radius-sharp); }

/* Footer */
.site-footer { background: var(--color-dark); color: white; padding: 4rem 0 2rem; }
.footer-flex { display: flex; justify-content: space-between; align-items: center; border-bottom: 1px solid #3d3d3d; padding-bottom: 2rem; margin-bottom: 2rem; }
.footer-brand img { height: 30px; filter: brightness(0) invert(1); margin-bottom: 0.5rem; }
.footer-brand p { color: var(--color-gray); font-size: 0.85rem; text-transform: uppercase; }
.footer-mail { font-family: var(--font-heading); font-size: 1.5rem; color: var(--color-accent); }
.footer-bottom { text-align: center; color: var(--color-gray); font-size: 0.85rem; }

/* Responsive */
@media (max-width: 900px) {
    .hero-grid, .category-grid, .promises-grid, .brand-index-grid, .guide-layout, .support-grid, .contact-body { grid-template-columns: 1fr; }
    .guide-sidebar { position: static; margin-bottom: 2rem; }
    .filter-flex { flex-direction: column; }
}
@media (max-width: 600px) {
    .main-nav { display: flex; overflow-x: auto; max-width: 100%; white-space: nowrap; padding-bottom: 10px; gap: 1rem; scrollbar-width: none; } .main-nav::-webkit-scrollbar { display: none; }
    .hero-content h1 { font-size: 2.5rem; }
}

/* Prefers Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    * { animation: none !important; transition: none !important; }
    .quick-preview-drawer { transform: translateY(0); display: none; }
    .part-card:hover .quick-preview-drawer { display: block; }
}

/* --- layout fix pack (2026-03-17) --- */
.filter-bar { margin-bottom: 1rem; }
.faq-list { display:flex; flex-direction:column; gap:1rem; }
.footer-contact { text-align:right; }
.guide-content { display:block; }
@media (max-width: 900px) { .footer-contact { text-align:left; } }