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

:root {
    --primary: #1a3a5c;
    --primary-light: #2a5a8c;
    --primary-dark: #0f2440;
    --accent: #e8913a;
    --accent-light: #f0a85a;
    --bg: #f8f9fa;
    --bg-card: #ffffff;
    --text: #333333;
    --text-light: #666666;
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(255, 255, 255, 0.3);
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    --radius: 16px;
    --radius-sm: 8px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

[data-theme="dark"] {
    --bg: #1a1a2e;
    --bg-card: #16213e;
    --text: #e0e0e0;
    --text-light: #a0a0a0;
    --glass-bg: rgba(22, 33, 62, 0.85);
    --glass-border: rgba(255, 255, 255, 0.1);
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    overflow-x: hidden;
    transition: background var(--transition), color var(--transition);
}

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

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

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

h1, h2, h3, h4, h5, h6 {
    line-height: 1.3;
    margin-bottom: 0.5em;
}

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

p {
    margin-bottom: 1em;
}

/* Header & Nav */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    transition: background var(--transition);
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

nav a img {
    height: 40px;
    transition: transform var(--transition);
}

nav a img:hover {
    transform: scale(1.05);
}

nav ul {
    display: flex;
    list-style: none;
    gap: 8px;
}

nav ul li a {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    color: var(--text);
    font-size: 0.9rem;
    font-weight: 500;
    transition: all var(--transition);
    position: relative;
}

nav ul li a::after {
    content: '';
    position: absolute;
    bottom: 4px;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 60%;
    height: 2px;
    background: var(--accent);
    transition: transform var(--transition);
}

nav ul li a:hover::after {
    transform: translateX(-50%) scaleX(1);
}

nav ul li a:hover {
    background: rgba(232, 145, 58, 0.1);
    color: var(--accent);
}

#menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.8rem;
    color: var(--text);
    cursor: pointer;
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    transition: background var(--transition);
}

#menu-toggle:hover {
    background: rgba(232, 145, 58, 0.1);
}

/* Banner */
#banner {
    position: relative;
    height: 100vh;
    min-height: 500px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    margin-top: 70px;
}

#banner::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, #1a3a5c 0%, #2a5a8c 40%, #e8913a 100%);
    z-index: 0;
    animation: gradientMove 10s ease infinite;
    background-size: 200% 200%;
}

@keyframes gradientMove {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.banner-slide {
    position: absolute;
    text-align: center;
    color: #fff;
    padding: 40px;
    max-width: 800px;
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease;
    z-index: 1;
}

.banner-slide.active {
    opacity: 1;
    transform: translateY(0);
}

.banner-slide h1, .banner-slide h2 {
    font-size: 3rem;
    margin-bottom: 0.5em;
    text-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.banner-slide p {
    font-size: 1.2rem;
    margin-bottom: 1.5em;
    text-shadow: 0 1px 5px rgba(0,0,0,0.2);
}

.btn {
    display: inline-block;
    padding: 14px 40px;
    background: var(--accent);
    color: #fff;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all var(--transition);
    box-shadow: 0 4px 15px rgba(232, 145, 58, 0.3);
}

.btn:hover {
    background: var(--accent-light);
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(232, 145, 58, 0.4);
    color: #fff;
}

/* Main Sections */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

section {
    padding: 80px 0;
    opacity: 0;
    transform: translateY(40px);
    animation: fadeInUp 0.8s ease forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

section:nth-child(2) { animation-delay: 0.1s; }
section:nth-child(3) { animation-delay: 0.2s; }
section:nth-child(4) { animation-delay: 0.3s; }
section:nth-child(5) { animation-delay: 0.4s; }
section:nth-child(6) { animation-delay: 0.5s; }
section:nth-child(7) { animation-delay: 0.6s; }
section:nth-child(8) { animation-delay: 0.7s; }
section:nth-child(9) { animation-delay: 0.8s; }

section h2 {
    text-align: center;
    margin-bottom: 1.5em;
    color: var(--primary);
    position: relative;
    padding-bottom: 0.5em;
}

section h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: var(--accent);
    border-radius: 2px;
}

/* Product Grid */
.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin: 40px 0;
}

.product-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all var(--transition);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
}

.product-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.product-card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    transition: transform var(--transition);
}

.product-card:hover img {
    transform: scale(1.05);
}

.product-card h3 {
    padding: 20px 20px 10px;
    color: var(--primary);
}

.product-card p {
    padding: 0 20px 20px;
    color: var(--text-light);
    font-size: 0.95rem;
}

/* FAQ & Cards */
.faq-item, .case-item, article {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
    border: 1px solid var(--glass-border);
    transition: all var(--transition);
}

.faq-item:hover, .case-item:hover, article:hover {
    transform: translateX(5px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1);
}

.faq-item h3, .case-item h3, article h3, article h4 {
    color: var(--primary);
    margin-bottom: 0.5em;
    cursor: pointer;
}

.faq-item p, .case-item p, article p {
    color: var(--text-light);
}

blockquote {
    background: var(--glass-bg);
    border-left: 4px solid var(--accent);
    padding: 20px 24px;
    margin: 20px 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    font-style: italic;
    color: var(--text);
}

/* Lists */
ul, ol {
    padding-left: 20px;
    margin-bottom: 1em;
}

li {
    margin-bottom: 0.5em;
}

/* Contact */
#contact p {
    font-size: 1.05rem;
}

/* Footer */
footer {
    background: var(--primary-dark);
    color: rgba(255,255,255,0.8);
    text-align: center;
    padding: 40px 20px;
    margin-top: 60px;
}

footer a {
    color: var(--accent-light);
}

footer a:hover {
    color: #fff;
}

footer p {
    margin-bottom: 8px;
    font-size: 0.9rem;
}

/* Back to Top */
#back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--accent);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    box-shadow: 0 4px 15px rgba(232, 145, 58, 0.3);
    transition: all var(--transition);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
}

#back-to-top.show {
    opacity: 1;
    visibility: visible;
}

#back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(232, 145, 58, 0.4);
}

/* Responsive */
@media (max-width: 768px) {
    html { font-size: 14px; }

    nav ul {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--glass-bg);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 20px;
        border-bottom: 1px solid var(--glass-border);
        gap: 4px;
    }

    nav ul.open {
        display: flex;
    }

    nav ul li a {
        padding: 12px 20px;
        border-radius: var(--radius-sm);
    }

    #menu-toggle {
        display: block;
    }

    #banner {
        height: 70vh;
        min-height: 400px;
    }

    .banner-slide h1, .banner-slide h2 {
        font-size: 2rem;
    }

    .banner-slide p {
        font-size: 1rem;
    }

    section {
        padding: 60px 0;
    }

    .product-grid {
        grid-template-columns: 1fr;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.6rem; }
    h3 { font-size: 1.3rem; }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .product-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Dark Mode Toggle (optional, but we support it) */
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #1a1a2e;
        --bg-card: #16213e;
        --text: #e0e0e0;
        --text-light: #a0a0a0;
        --glass-bg: rgba(22, 33, 62, 0.85);
        --glass-border: rgba(255, 255, 255, 0.1);
        --shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    }
}

/* Additional Utility */
#sitemap ul, #friendlinks ul {
    list-style: none;
    padding: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
}

#sitemap ul li, #friendlinks ul li {
    margin: 0;
}

#sitemap ul li a, #friendlinks ul li a {
    padding: 8px 16px;
    background: var(--glass-bg);
    border-radius: var(--radius-sm);
    border: 1px solid var(--glass-border);
    transition: all var(--transition);
    display: inline-block;
}

#sitemap ul li a:hover, #friendlinks ul li a:hover {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}

time {
    color: var(--text-light);
    font-size: 0.85rem;
    display: block;
    margin-bottom: 8px;
}

/* Smooth scroll for anchor offsets */
section[id] {
    scroll-margin-top: 80px;
}

/* Print */
@media print {
    header, #back-to-top, footer {
        display: none;
    }
    body {
        background: #fff;
        color: #000;
    }
}
```