:root {
    --bg-color: #ffffff;
    --text-primary: #202124;
    --text-secondary: #5f6368;
    --accent-blue: #1a73e8;
    --surface-color: #f8f9fa;
    --border-color: #dadce0;
    --card-shadow: 0 1px 2px 0 rgba(60,64,67,0.3), 0 1px 3px 1px rgba(60,64,67,0.15);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #202124;
        --text-primary: #e8eaed;
        --text-secondary: #9aa0a6;
        --accent-blue: #8ab4f8;
        --surface-color: #303134;
        --border-color: #5f6368;
        --card-shadow: 0 1px 2px 0 rgba(0,0,0,0.3), 0 1px 3px 1px rgba(0,0,0,0.15);
    }
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Google Sans', 'Roboto', sans-serif; }
body { background: var(--bg-color); color: var(--text-primary); line-height: 1.6; transition: 0.3s; }

/* Navbar */
.navbar { display: flex; justify-content: space-between; padding: 20px; max-width: 1200px; margin: 0 auto; align-items: center; }
.logo { font-weight: 700; font-size: 1.1rem; letter-spacing: -0.5px; }
#lang-toggle { background: transparent; border: 1px solid var(--border-color); color: var(--text-primary); padding: 6px 16px; border-radius: 20px; cursor: pointer; }

/* Hero */
.hero-section { text-align: center; padding: 80px 20px 60px; max-width: 900px; margin: 0 auto; }
.badge { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 1px; color: var(--text-secondary); background: var(--surface-color); padding: 4px 12px; border-radius: 4px; }
h1 { font-size: 2.8rem; line-height: 1.2; margin: 20px 0; letter-spacing: -1px; }
p { color: var(--text-secondary); font-size: 1.1rem; max-width: 600px; margin: 0 auto 30px; }

/* Buttons */
.cta-container { display: flex; gap: 20px; justify-content: center; align-items: center; }
.primary-btn { background: var(--accent-blue); color: #fff; border: none; padding: 14px 32px; border-radius: 50px; font-size: 1rem; font-weight: 500; cursor: pointer; transition: transform 0.2s; box-shadow: var(--card-shadow); }
.primary-btn:hover { transform: translateY(-2px); }
.text-link { color: var(--accent-blue); text-decoration: none; font-weight: 500; }

/* Stats Bar */
.stats-bar { display: flex; justify-content: center; gap: 50px; padding: 40px 20px; border-top: 1px solid var(--border-color); border-bottom: 1px solid var(--border-color); margin-bottom: 60px; background: var(--surface-color); }
.stat-item { text-align: center; }
.stat-item strong { display: block; font-size: 1.8rem; color: var(--accent-blue); }
.stat-item span { font-size: 0.9rem; color: var(--text-secondary); }

/* General Sections */
.section-container { max-width: 1000px; margin: 0 auto 80px; padding: 0 20px; }
.section-title { font-size: 1.8rem; margin-bottom: 30px; text-align: center; }

/* Service Cards */
.cards-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 30px; }
.card { background: var(--surface-color); padding: 30px; border-radius: 16px; border: 1px solid transparent; transition: 0.3s; }
.card:hover { border-color: var(--accent-blue); box-shadow: var(--card-shadow); }
.card-icon { font-size: 2.5rem; color: var(--accent-blue); margin-bottom: 20px; }
.card h3 { margin-bottom: 10px; font-size: 1.3rem; }
.detail-list { list-style: none; margin-top: 20px; border-top: 1px solid var(--border-color); padding-top: 20px; }
.detail-list li { margin-bottom: 10px; font-size: 0.95rem; display: flex; align-items: center; color: var(--text-secondary); }
.detail-list li::before { content: "•"; color: var(--accent-blue); margin-right: 10px; font-weight: bold; }

/* Product Grid */
.product-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 15px; }
.prod-card { background: var(--surface-color); padding: 20px; text-align: center; border-radius: 12px; font-weight: 500; font-size: 0.9rem; transition: 0.2s; }
.prod-card:hover { background: var(--accent-blue); color: #fff; }

/* About / Footer */
.about-section { background: var(--surface-color); padding: 60px 20px; text-align: center; }

/* Footer Upgrade */
footer {
    background-color: var(--surface-color);
    padding: 40px 20px;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center; /* 核心：强制水平居中 */
    justify-content: center;
    text-align: center; /* 确保文字换行后也是居中的 */
    gap: 10px; /* 两行文字之间的间距 */
    max-width: 800px;
    margin: 0 auto;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.copyright {
    font-weight: 500;
    opacity: 0.8;
}

.address {
    opacity: 0.7;
    line-height: 1.5;
}

.ad-container-hidden { display: none; margin-top: 20px; }

/* Mobile */
@media (max-width: 768px) {
    h1 { font-size: 2rem; }
    .stats-bar { flex-direction: column; gap: 30px; }
    .hero-section { padding-top: 40px; }
}