/* ================================
   Panrui Compressor Landing Page
   CSS Stylesheet
   ================================ */

/* CSS Variables */
:root {
    --primary-color: #1976D2;
    --secondary-color: #424242;
    --accent-color: #FF6B35;
    --bg-light: #F5F5F5;
    --bg-white: #FFFFFF;
    --text-dark: #212121;
    --text-light: #757575;
    --border-color: #E0E0E0;
    --success-color: #4CAF50;
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 48px;
    --spacing-xl: 64px;
    --border-radius: 8px;
    --box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --box-shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-white);
    font-size: 16px;
}

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

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

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

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

.container-wide {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header */
.header {
    background-color: var(--bg-white);
    box-shadow: var(--box-shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: var(--spacing-sm) 0;
}

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

.site-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
}

.whatsapp-btn {
    background-color: var(--success-color);
    color: var(--bg-white);
    padding: 12px 24px;
    border-radius: var(--border-radius);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 16px;
}

.whatsapp-btn:hover {
    background-color: #45a049;
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-hover);
    color: var(--bg-white);
}

/* Hero Section */
.hero {
    background-image: url('../images/hero-bg-image.jpg');
    background-position: center center;
    background-size: cover;
    background-repeat: no-repeat;
    height: 500px;
    width: 100%;
}

/* Why Buy From Us Section */
.why-buy-section {
    background: linear-gradient(135deg, var(--primary-color), #1565C0);
    color: var(--bg-white);
    text-align: center;
    padding: var(--spacing-xl) 0;
}

.why-buy-title {
    font-size: 48px;
    margin-bottom: var(--spacing-md);
    font-weight: 700;
    color: var(--bg-white);
}

.why-buy-text {
    font-size: 20px;
    margin-bottom: var(--spacing-lg);
    color: var(--bg-white);
}

/* Section Styles */
.section {
    padding: var(--spacing-xl) 0;
}

.section-alt {
    background-color: var(--bg-light);
}

.section-title {
    font-size: 36px;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--text-dark);
    font-weight: 700;
}

.section-subtitle {
    font-size: 18px;
    text-align: center;
    margin-bottom: var(--spacing-md);
    color: var(--text-light);
}

/* Grid Layouts */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

/* Card Styles */
.card {
    background-color: var(--bg-white);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-hover);
}

.card-image {
    width: 100%;
    height: 250px;
    object-fit: contain;
    background-color: var(--bg-light);
}

.card-content {
    padding: var(--spacing-md);
}

.card-title {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

.card-text {
    font-size: 16px;
    color: var(--text-light);
    line-height: 1.6;
}

/* Certificate Grid */
.cert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.cert-item {
    text-align: center;
    background-color: var(--bg-white);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.cert-image {
    width: 100%;
    height: 200px;
    object-fit: contain;
    margin-bottom: var(--spacing-sm);
    background-color: var(--bg-light);
    border-radius: var(--border-radius);
}

.cert-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
}

/* Product Cards */
.product-card {
    background-color: var(--bg-white);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-hover);
}

.product-image {
    width: 100%;
    height: 300px;
    object-fit: cover;
    background-color: var(--bg-light);
}

.product-content {
    padding: var(--spacing-md);
}

.product-title {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--primary-color);
}

.product-description {
    font-size: 16px;
    color: var(--text-light);
    margin-bottom: var(--spacing-sm);
}

/* Factory Section */
.factory-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.factory-text h2 {
    font-size: 32px;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
}

.factory-text p {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-light);
    margin-bottom: var(--spacing-sm);
}

.factory-image {
    width: 100%;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

/* Features List */
.features-list {
    list-style: none;
    margin: var(--spacing-md) 0;
}

.features-list li {
    padding: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    background-color: var(--bg-light);
    border-left: 4px solid var(--primary-color);
    border-radius: 4px;
    font-size: 16px;
}

/* Contact Section */
.contact-section {
    background: linear-gradient(135deg, var(--primary-color), #1565C0);
    color: var(--bg-white);
    text-align: center;
}

.contact-section h2 {
    color: var(--bg-white);
    font-size: 36px;
    margin-bottom: var(--spacing-md);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    max-width: 600px;
    margin: 0 auto var(--spacing-lg);
}

.contact-item {
    font-size: 18px;
    padding: var(--spacing-sm);
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
}

.contact-item a {
    color: var(--bg-white);
    font-weight: 600;
}

.marketing-text {
    font-size: 20px;
    margin: var(--spacing-md) 0;
    font-weight: 600;
}

/* Footer */
.footer {
    background-color: var(--secondary-color);
    color: var(--bg-white);
    text-align: center;
    padding: var(--spacing-lg) 0;
}

.footer p {
    margin-bottom: var(--spacing-sm);
    font-size: 16px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero {
        height: 300px;
    }
    
    .why-buy-title {
        font-size: 32px;
    }
    
    .why-buy-text {
        font-size: 18px;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .factory-content {
        grid-template-columns: 1fr;
    }
    
    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }
    
    .header-content {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .site-title {
        font-size: 20px;
    }
    
    .product-image {
        height: 250px;
    }
}

@media (max-width: 480px) {
    .hero {
        height: 250px;
    }
    
    .why-buy-title {
        font-size: 24px;
    }
    
    .why-buy-text {
        font-size: 16px;
    }
    
    .section {
        padding: var(--spacing-lg) 0;
    }
    
    .whatsapp-btn {
        width: 100%;
        justify-content: center;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mb-lg {
    margin-bottom: var(--spacing-lg);
}

.mt-lg {
    margin-top: var(--spacing-lg);
}

.btn-large {
    font-size: 18px;
    padding: 16px 32px;
}