:root {
    --primary-dark: #0a1628;
    --medium-blue: #1a365d;
    --accent-blue: #2563eb;
    --accent-green: #10b981;
    --light-bg: #f8fafc;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --white: #ffffff;
    --border-color: #e2e8f0;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text-main);
    background-color: var(--white);
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

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

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

header {
    background-color: var(--primary-dark);
    color: var(--white);
    padding: 1.5rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--white);
}

.logo span {
    color: var(--accent-green);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a:hover {
    color: var(--accent-green);
    transition: 0.3s;
}

.mobile-menu-btn {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
}

footer {
    background-color: var(--primary-dark);
    color: var(--white);
    padding: 4rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-col h4 {
    margin-bottom: 1.5rem;
    color: var(--accent-green);
}

.footer-col p, .footer-col li {
    color: #cbd5e1;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 2rem;
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Sections */
section {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title h2 {
    font-size: 2.5rem;
    color: var(--primary-dark);
    margin-bottom: 1rem;
}

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.8rem 2rem;
    border-radius: 4px;
    font-weight: 600;
    transition: 0.3s;
    cursor: pointer;
    border: none;
}

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

.btn-primary:hover {
    background-color: #1d4ed8;
}

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--white);
    color: var(--white);
}

.btn-outline:hover {
    background-color: var(--white);
    color: var(--primary-dark);
}

/* Hero Section */
.hero {
    background: linear-gradient(rgba(10, 22, 40, 0.78), rgba(10, 22, 40, 0.78)),
                url('https://www.jjr.com.cn/_nuxt/banner-product.9ca7d487.jpg') center/cover no-repeat;
    color: var(--white);
    padding: 8rem 0;
    position: relative;
    overflow: hidden;
}

.hero-content {
    max-width: 650px;
    position: relative;
    z-index: 2;
}

.hero h1 {
    font-size: 3.5rem;
    line-height: 1.2;
    margin-bottom: 1.5rem;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    color: #cbd5e1;
}

.hero-btns {
    display: flex;
    gap: 1rem;
}

.hero-visual {
    position: absolute;
    right: 5%;
    top: 50%;
    transform: translateY(-50%);
    width: 40%;
    height: 400px;
    background: url('https://images.unsplash.com/photo-1589714269969-681d7a4dd101?fm=jpg&q=80&w=800&auto=format&fit=crop') center/cover no-repeat;
    opacity: 0.6;
    border-radius: 20px;
    z-index: 1;
    box-shadow: 0 20px 50px rgba(0,0,0,0.3);
}

.hero-small {
    padding: 4rem 0;
    background: linear-gradient(rgba(10, 22, 40, 0.8), rgba(10, 22, 40, 0.8)),
                url('https://www.jjr.com.cn/_nuxt/banner-about.b64ec063.jpg') center/cover no-repeat;
}

/* Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    text-align: center;
}

.stat-item h3 {
    font-size: 3rem;
    color: var(--accent-blue);
    margin-bottom: 0.5rem;
}

.stat-item p {
    font-weight: 600;
    color: var(--text-muted);
}

/* Features/Capabilities Cards */
.grid-4 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.card {
    background-color: var(--white);
    padding: 2.5rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    transition: transform 0.3s;
    border-top: 4px solid var(--accent-blue);
}

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

.card h3 {
    margin-bottom: 1rem;
    color: var(--primary-dark);
}

.card-icon {
    width: 50px;
    height: 50px;
    background-color: var(--light-bg);
    border-radius: 8px;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-blue);
    font-size: 1.5rem;
    font-weight: bold;
}

/* WhatsApp Button */
.wa-float {
    position: fixed;
    bottom: 40px;
    right: 40px;
    background-color: #25d366;
    color: #FFF;
    border-radius: 50px;
    text-align: center;
    font-size: 30px;
    box-shadow: 2px 2px 3px #999;
    z-index: 100;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: 0.3s;
}

.wa-float:hover {
    background-color: #128c7e;
    transform: scale(1.1);
}

/* ROI Calculator */
.roi-form {
    background-color: var(--light-bg);
    padding: 3rem;
    border-radius: 12px;
    max-width: 800px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.form-group input, .form-group select {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}

.roi-result {
    margin-top: 3rem;
    padding: 2rem;
    background-color: var(--primary-dark);
    color: var(--white);
    border-radius: 8px;
    display: none;
}

.roi-value {
    font-size: 2.5rem;
    color: var(--accent-green);
    font-weight: bold;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
}

table th, table td {
    padding: 1rem;
    border: 1px solid var(--border-color);
    text-align: left;
}

table th {
    background-color: var(--light-bg);
}

/* Diagrams (Placeholder) */
.diagram-placeholder {
    background: url('https://images.unsplash.com/photo-1604847047676-da9a84adbd08?fm=jpg&q=80&w=800&auto=format&fit=crop') center/cover no-repeat;
    border: 1px solid var(--border-color);
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    border-radius: 8px;
}

.circle-node {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--accent-blue);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    font-size: 0.8rem;
    font-weight: bold;
    z-index: 2;
}

.line-connector {
    position: absolute;
    background: var(--accent-blue);
    height: 2px;
    z-index: 1;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    .mobile-menu-btn {
        display: block;
    }
    .hero h1 {
        font-size: 2.5rem;
    }
    .hero-visual {
        display: none;
    }
    .section-title h2 {
        font-size: 2rem;
    }
}