:root {
    --primary-green: #1a7a4c;
    --dark-green: #0d4a2e;
    --light-green: #e8f5e9;
    --accent-blue: #1565c0;
    --text-color: #333;
    --text-light: #666;
    --white: #ffffff;
    --bg-light: #f9fbf9;
    --shadow: 0 4px 6px rgba(0,0,0,0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-light);
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header & Nav */
header {
    background-color: var(--white);
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

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

.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary-green);
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a:hover {
    color: var(--primary-green);
}

.nav-links a.active {
    color: var(--primary-green);
    font-weight: 700;
}

.mobile-menu-btn {
    display: none;
    cursor: pointer;
    font-size: 24px;
}

/* Sections */
section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
}

.section-title h2 {
    font-size: 36px;
    color: var(--dark-green);
    margin-bottom: 15px;
}

.section-title p {
    color: var(--text-light);
    max-width: 700px;
    margin: 0 auto;
}

/* Hero */
.hero {
    height: 90vh;
    background: linear-gradient(rgba(13, 74, 46, 0.65), rgba(13, 74, 46, 0.65)),
                url('https://www.jjr.com.cn/_nuxt/banner-product.9ca7d487.jpg') center/cover no-repeat;
    color: var(--white);
    display: flex;
    align-items: center;
    text-align: center;
}

.hero-content h1 {
    font-size: 56px;
    margin-bottom: 25px;
    line-height: 1.1;
    font-weight: 900;
}

.hero-content p {
    font-size: 20px;
    margin-bottom: 40px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    opacity: 0.9;
}

.btn {
    display: inline-block;
    padding: 15px 35px;
    border-radius: 50px;
    font-weight: 700;
    cursor: pointer;
    border: none;
    text-transform: uppercase;
    letter-spacing: 1px;
}

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

.btn-primary:hover {
    background-color: var(--dark-green);
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

/* Benefits Card */
.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.benefit-card {
    background: var(--white);
    padding: 40px;
    border-radius: 15px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.benefit-card:hover {
    transform: translateY(-10px);
}

.benefit-card i {
    font-size: 40px;
    color: var(--primary-green);
    margin-bottom: 20px;
    display: block;
}

.benefit-card h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--dark-green);
}

.benefit-card .stat {
    font-size: 32px;
    font-weight: 800;
    color: var(--accent-blue);
    margin: 10px 0;
}

/* Case Studies */
.project-card {
    background: var(--white);
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.project-img {
    height: 250px;
    background: url('https://www.jjr.com.cn/_nuxt/001.787161eb.jpg') center/cover no-repeat;
    position: relative;
    overflow: hidden;
}

.project-img::after {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: linear-gradient(transparent, rgba(0,0,0,0.5));
}

.project-info {
    padding: 30px;
}

.project-info h3 {
    margin-bottom: 10px;
    color: var(--dark-green);
}

.project-tags {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}

.tag {
    font-size: 12px;
    padding: 4px 10px;
    background: var(--light-green);
    color: var(--primary-green);
    border-radius: 4px;
    font-weight: 600;
}

/* WhatsApp Floating Button */
.whatsapp-float {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: #25d366;
    color: white;
    width: 60px;
    height: 60px;
    border-radius: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 30px;
    box-shadow: 2px 2px 10px rgba(0,0,0,0.2);
    z-index: 1000;
    transition: var(--transition);
}

.whatsapp-float:hover {
    transform: scale(1.1);
}

/* Footer */
footer {
    background-color: var(--dark-green);
    color: var(--white);
    padding: 60px 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    margin-bottom: 25px;
    font-size: 20px;
}

.footer-col ul li {
    margin-bottom: 12px;
    opacity: 0.8;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 20px;
    text-align: center;
    font-size: 14px;
    opacity: 0.6;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    .mobile-menu-btn {
        display: block;
    }
    .hero-content h1 {
        font-size: 36px;
    }
    section {
        padding: 50px 0;
    }
}

/* Utils */
.placeholder-bg {
    background: url('https://images.unsplash.com/photo-1596289396270-898cde8584b9?fm=jpg&q=80&w=800&auto=format&fit=crop') center/cover no-repeat;
}
.text-accent { color: var(--accent-blue); }