/* === PREVIEW SHELL === */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Inter', system-ui, sans-serif; background: #0f0f13; color: #e0e0e0; }

.preview-header {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    padding: 40px 0 0;
    text-align: center;
    position: sticky; top: 0; z-index: 9999;
    box-shadow: 0 4px 30px rgba(0,0,0,0.5);
}
.preview-header h1 {
    font-family: 'Montserrat', sans-serif;
    font-size: 28px; font-weight: 800; color: #fff;
    margin-bottom: 6px; letter-spacing: -0.5px;
}
.preview-header p {
    color: rgba(255,255,255,0.6); font-size: 14px; margin-bottom: 24px;
}

.tab-nav {
    display: flex; justify-content: center; gap: 4px;
}
.tab-btn {
    padding: 14px 32px; border: none; cursor: pointer;
    font-family: 'Montserrat', sans-serif; font-size: 14px; font-weight: 700;
    text-transform: uppercase; letter-spacing: 0.5px;
    background: rgba(255,255,255,0.05); color: rgba(255,255,255,0.5);
    border-radius: 12px 12px 0 0; transition: all 0.3s;
    border-bottom: 3px solid transparent;
}
.tab-btn:hover { background: rgba(255,255,255,0.1); color: rgba(255,255,255,0.8); }
.tab-btn.active-red { background: rgba(196,30,58,0.2); color: #C41E3A; border-bottom-color: #C41E3A; }
.tab-btn.active-green { background: rgba(46,125,50,0.2); color: #2E7D32; border-bottom-color: #2E7D32; }
.tab-btn.active-orange { background: rgba(255,109,0,0.2); color: #FF6D00; border-bottom-color: #FF6D00; }

.tab-indicator { display: flex; align-items: center; gap: 8px; }
.tab-dot { width: 10px; height: 10px; border-radius: 50%; }
.tab-dot.red { background: #C41E3A; }
.tab-dot.green { background: #2E7D32; }
.tab-dot.orange { background: #FF6D00; }

.site-panel { display: none; }
.site-panel.active { display: block; }

.site-frame {
    max-width: 1400px; margin: 0 auto;
    background: #fff; min-height: 100vh;
    box-shadow: 0 0 60px rgba(0,0,0,0.5);
}

 

/* ===================== SITE 3: ORANGE VITALITY ===================== */
.s3 { font-family: 'Nunito', sans-serif; color: #212121; background: #FAFAFA; line-height: 1.7; overflow-x: hidden; }
.s3 a { color: #FF6D00; text-decoration: none; transition: color 0.3s; }
.s3 a:hover { color: #E65100; }
.s3 img { max-width: 100%; height: auto; }
.s3 h1, .s3 h2, .s3 h3, .s3 h4, .s3 h5, .s3 h6 { font-family: 'Montserrat', sans-serif; font-weight: 700; line-height: 1.3; }
.s3 .container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.s3 .text-center { text-align: center; }
.s3 .mt-4 { margin-top: 2rem; }
.s3 .btn { display: inline-block; padding: 12px 28px; border-radius: 8px; font-weight: 700; font-family: 'Montserrat', sans-serif; font-size: 14px; text-transform: uppercase; letter-spacing: 0.5px; border: none; cursor: pointer; transition: all 0.3s; text-align: center; text-decoration: none; }
.s3 .btn-primary { background: linear-gradient(135deg, #FF6D00, #E65100); color: #fff; box-shadow: 0 4px 15px rgba(255,109,0,0.3); }
.s3 .btn-primary:hover { transform: translateY(-3px); box-shadow: 0 8px 25px rgba(255,109,0,0.5); color: #fff; }
.s3 .btn-outline { border: 2px solid #fff; color: #fff; background: transparent; }
.s3 .btn-outline:hover { background: #fff; color: #FF6D00; }
.s3 .btn-white { background: #fff; color: #FF6D00; }
.s3 .btn-white:hover { background: #FFF3E0; color: #E65100; }
.s3 .btn-lg { padding: 16px 36px; font-size: 15px; }
.s3 .btn-sm { padding: 8px 16px; font-size: 12px; }
.s3 .top-bar { background: #212121; color: #aaa; font-size: 13px; padding: 8px 0; }
.s3 .top-bar-inner { display: flex; justify-content: space-between; align-items: center; }
.s3 .top-bar-left { display: flex; gap: 24px; }
.s3 .top-bar-left span { display: flex; align-items: center; gap: 6px; }
.s3 .top-bar-left i { color: #FF6D00; }
.s3 .language-switch { 
    display: flex; 
    gap: 6px; 
    align-items: center;
}
.s3 .lang-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border: 1px solid rgba(255,255,255,0.2);
    background: transparent;
    color: #aaa;
    font-size: 12px;
    font-weight: 600;
    font-family: 'Montserrat', sans-serif;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    position: relative;
    overflow: hidden;
}
.s3 .lang-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,109,0,0.2), transparent);
    transition: left 0.5s ease;
}
.s3 .lang-btn:hover::before {
    left: 100%;
}
.s3 .lang-btn:hover {
    border-color: #FF6D00;
    color: #FF6D00;
    background: rgba(255,109,0,0.1);
    transform: translateY(-1px);
}
.s3 .lang-btn.active {
    background: linear-gradient(135deg, #FF6D00, #E65100);
    border-color: #FF6D00;
    color: #fff;
    box-shadow: 0 2px 8px rgba(255,109,0,0.3);
}
.s3 .lang-btn.active:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(255,109,0,0.4);
}
.s3 .lang-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    border-radius: 4px;
    background: rgba(255,255,255,0.1);
    font-size: 11px;
    font-weight: 700;
    transition: all 0.3s ease;
}
.s3 .lang-btn.active .lang-icon {
    background: rgba(255,255,255,0.25);
}
.s3 .lang-text {
    display: none;
}
@media (min-width: 768px) {
    .s3 .lang-text {
        display: inline;
    }
    .s3 .lang-btn {
        padding: 6px 14px;
    }
}
.s3 .main-nav-bar { background: #fff; position: sticky; top: 0; z-index: 100; box-shadow: 0 2px 20px rgba(0,0,0,0.08); }
.s3 .nav-inner { display: flex; justify-content: space-between; align-items: center; height: 72px; }
.s3 .logo { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.s3 .logo-icon { font-size: 28px; color: #FF6D00; }
.s3 .logo-text { font-family: 'Montserrat', sans-serif; font-size: 24px; font-weight: 800; color: #212121; letter-spacing: -0.5px; }
.s3 .logo-text .accent { color: #FF6D00; }
.s3 .nav-menu { display: flex; align-items: center; list-style: none; gap: 4px; padding: 0; margin: 0; }
.s3 .nav-menu a { padding: 8px 16px; color: #333; font-weight: 600; font-size: 14px; text-decoration: none; border-radius: 8px; transition: all 0.3s; position: relative; display: inline-block; }
.s3 .nav-menu a::after { content: ''; position: absolute; bottom: 0; left: 50%; width: 0; height: 3px; background: #FF6D00; transition: all 0.3s; transform: translateX(-50%); border-radius: 2px; }
.s3 .nav-menu a:hover { color: #FF6D00; }
.s3 .nav-menu a:hover::after { width: 60%; }
.s3 .nav-menu a.active { color: #FF6D00; font-weight: 700; }
.s3 .nav-menu a.active::after { width: 60%; }
.s3 .nav-cta { background: linear-gradient(135deg, #FF6D00, #E65100) !important; color: #fff !important; border-radius: 8px !important; padding: 10px 20px !important; box-shadow: 0 2px 8px rgba(255,109,0,0.3); }
.s3 .nav-cta:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(255,109,0,0.4); }
.s3 .nav-cta::after { display: none !important; }
.s3 .nav-cta.active { background: linear-gradient(135deg, #E65100, #BF360C) !important; box-shadow: 0 4px 12px rgba(255,109,0,0.5); }
.s3 .hero { position: relative; min-height: 600px; background: linear-gradient(135deg, #212121 0%, #333 50%, #FF6D00 100%); overflow: hidden; display: flex; align-items: center; padding: 80px 0; }
.s3 .hero-bg-pattern { position: absolute; top: 0; left: 0; right: 0; bottom: 0; background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23FF6D00' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E"); opacity: 0.5; }
.s3 .hero-diagonal { position: absolute; right: -5%; top: -10%; width: 55%; height: 120%; background: linear-gradient(135deg, rgba(255,109,0,0.2), rgba(230,81,0,0.3)); transform: skewX(-12deg); border-left: 4px solid rgba(255,109,0,0.5); }
.s3 .hero-inner { display: flex; align-items: center; justify-content: space-between; position: relative; z-index: 2; }
.s3 .hero-content { max-width: 550px; }
.s3 .hero-content h1 { font-size: 52px; color: #fff; font-weight: 900; margin-bottom: 16px; text-transform: uppercase; letter-spacing: -1px; line-height: 1.1; }
.s3 .hero-content p { font-size: 18px; color: rgba(255,255,255,0.8); margin-bottom: 32px; line-height: 1.6; }
.s3 .hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }
.s3 .hero-visual { position: relative; width: 400px; height: 400px; flex-shrink: 0; }
.s3 .hero-shape { position: relative; width: 100%; height: 100%; }
.s3 .hero-gear { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); font-size: 120px; color: rgba(255,109,0,0.6); }
.s3 .hero-gear-sm { position: absolute; top: 25%; left: 70%; font-size: 60px; color: rgba(255,109,0,0.4); }
.s3 .hero-svg { position: absolute; top: 0; left: 0; width: 100%; height: 100%; animation: s3heroRotate 30s linear infinite; }
@keyframes s3heroRotate { to { transform: rotate(360deg); } }
.s3 .fa-spin-reverse { animation: s3faSpin 3s linear infinite reverse; }
@keyframes s3faSpin { to { transform: rotate(360deg); } }
.s3 .stats-section { background: #fff; padding: 50px 0; margin-top: -40px; position: relative; z-index: 3; border-radius: 20px 20px 0 0; box-shadow: 0 -10px 40px rgba(0,0,0,0.1); }
.s3 .stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 30px; text-align: center; }
.s3 .stat-item { padding: 20px; }
.s3 .stat-number { font-family: 'Montserrat', sans-serif; font-size: 48px; font-weight: 900; color: #FF6D00; line-height: 1; }
.s3 .stat-label { font-size: 15px; color: #666; margin-top: 8px; font-weight: 600; }
.s3 .section { padding: 80px 0; position: relative; }
.s3 .section-header { text-align: center; margin-bottom: 50px; }
.s3 .section-header.light h2, .s3 .section-header.light .section-tag { color: #fff; }
.s3 .section-tag { display: inline-block; background: #FFF3E0; color: #E65100; padding: 6px 20px; border-radius: 30px; font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; margin-bottom: 12px; }
.s3 .section-header.light .section-tag { background: rgba(255,255,255,0.15); color: #FFF3E0; }
.s3 .section-header h2 { font-size: 36px; margin-bottom: 12px; }
.s3 .section-line { width: 60px; height: 4px; background: linear-gradient(90deg, #FF6D00, #E65100); margin: 0 auto; border-radius: 2px; }
.s3 .products-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.s3 .product-card { background: #fff; border-radius: 16px; overflow: hidden; box-shadow: 0 4px 20px rgba(0,0,0,0.06); transition: all 0.4s; border: 1px solid #f0f0f0; }
.s3 .product-card:hover { transform: translateY(-8px); box-shadow: 0 12px 40px rgba(255,109,0,0.15); border-color: #FF6D00; }
.s3 .product-card-img { position: relative; height: 220px; background: linear-gradient(135deg, #f5f5f5, #e0e0e0); overflow: hidden; }
.s3 .product-card-overlay { position: absolute; top: 0; left: 0; right: 0; bottom: 0; background: rgba(33,33,33,0.7); display: flex; align-items: center; justify-content: center; opacity: 0; transition: opacity 0.4s; z-index: 2; }
.s3 .product-card:hover .product-card-overlay { opacity: 1; }
.s3 .product-image { 
    width: 100%; 
    height: 100%; 
    object-fit: cover; 
    position: absolute; 
    top: 0; 
    left: 0; 
    transition: transform 0.3s;
}
.s3 .product-card:hover .product-image { 
    transform: scale(1.05); 
}
.s3 .product-placeholder-img { 
    width: 100%; 
    height: 100%; 
    display: flex; 
    align-items: center; 
    justify-content: center; 
    font-size: 48px; 
    color: #ccc; 
    background: linear-gradient(135deg, #f9f9f9, #eee); 
    position: absolute;
    top: 0;
    left: 0;
}
.s3 .product-cat-badge { position: absolute; top: 12px; left: 12px; background: #FF6D00; color: #fff; padding: 4px 12px; border-radius: 20px; font-size: 11px; font-weight: 700; text-transform: uppercase; z-index: 1; }
.s3 .product-card-body { padding: 20px; }
.s3 .product-card-body h3 { font-size: 18px; margin-bottom: 8px; }
.s3 .product-card-body p { font-size: 14px; color: #666; margin-bottom: 12px; }
.s3 .card-link { font-size: 14px; font-weight: 700; color: #FF6D00; display: inline-flex; align-items: center; gap: 6px; transition: gap 0.3s; }
.s3 .card-link:hover { gap: 10px; color: #E65100; }
.s3 .why-section { background: linear-gradient(135deg, #212121, #333); position: relative; overflow: hidden; }
.s3 .why-diagonal-bg { position: absolute; top: -20%; right: -10%; width: 50%; height: 140%; background: rgba(255,109,0,0.1); transform: skewX(-15deg); }
.s3 .why-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 30px; position: relative; z-index: 1; }
.s3 .why-card { text-align: center; padding: 40px 24px; background: rgba(255,255,255,0.05); border-radius: 16px; border: 1px solid rgba(255,255,255,0.08); transition: all 0.4s; }
.s3 .why-card:hover { background: rgba(255,109,0,0.15); transform: translateY(-8px); border-color: rgba(255,109,0,0.3); }
.s3 .why-icon { width: 72px; height: 72px; margin: 0 auto 20px; border-radius: 16px; background: linear-gradient(135deg, #FF6D00, #E65100); display: flex; align-items: center; justify-content: center; font-size: 28px; color: #fff; transform: rotate(-5deg); transition: transform 0.3s; }
.s3 .why-card:hover .why-icon { transform: rotate(0deg) scale(1.1); }
.s3 .why-card h3 { color: #fff; font-size: 18px; margin-bottom: 10px; }
.s3 .why-card p { color: rgba(255,255,255,0.7); font-size: 14px; }
.s3 .video-section { background: #f5f5f5; }
.s3 .video-wrapper { max-width: 900px; margin: 0 auto; }
.s3 .video-placeholder { height: 450px; background: linear-gradient(135deg, #212121, #333); border-radius: 20px; display: flex; flex-direction: column; align-items: center; justify-content: center; color: #fff; cursor: pointer; transition: all 0.4s; position: relative; overflow: hidden; }
.s3 .video-placeholder::before { content: ''; position: absolute; top: 0; left: 0; right: 0; bottom: 0; background: repeating-linear-gradient(45deg, transparent, transparent 20px, rgba(255,109,0,0.03) 20px, rgba(255,109,0,0.03) 40px); }
.s3 .video-placeholder i { font-size: 72px; color: #FF6D00; margin-bottom: 16px; position: relative; }
.s3 .video-placeholder p { font-size: 16px; color: #aaa; position: relative; }
.s3 .video-placeholder:hover { transform: scale(1.02); box-shadow: 0 20px 60px rgba(0,0,0,0.3); }
.s3 .news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.s3 .news-card { background: #fff; border-radius: 16px; overflow: hidden; box-shadow: 0 4px 20px rgba(0,0,0,0.06); transition: all 0.4s; }
.s3 .news-card:hover { transform: translateY(-6px); box-shadow: 0 12px 40px rgba(255,109,0,0.12); }
.s3 .news-card-img { height: 200px; background: linear-gradient(135deg, #FFF3E0, #FFE0B2); position: relative; display: flex; align-items: center; justify-content: center; }
.s3 .news-placeholder-img { font-size: 48px; color: #FF6D00; opacity: 0.3; }
.s3 .news-date { position: absolute; bottom: 12px; right: 12px; background: #FF6D00; color: #fff; padding: 4px 12px; border-radius: 6px; font-size: 12px; font-weight: 600; }
.s3 .news-card-body { padding: 20px; }
.s3 .news-card-body h3 { font-size: 17px; margin-bottom: 10px; }
.s3 .news-card-body p { font-size: 14px; color: #666; margin-bottom: 12px; }
.s3 .cta-section { background: linear-gradient(135deg, #FF6D00, #E65100); padding: 80px 0; position: relative; overflow: hidden; }
.s3 .cta-diagonal { position: absolute; left: -10%; top: -30%; width: 40%; height: 160%; background: rgba(255,255,255,0.05); transform: skewX(15deg); }
.s3 .cta-section h2 { color: #fff; font-size: 36px; margin-bottom: 12px; position: relative; }
.s3 .cta-section p { color: rgba(255,255,255,0.8); font-size: 18px; margin-bottom: 28px; position: relative; }
.s3 .site-footer { background: #212121; color: #aaa; padding: 60px 0 0; position: relative; overflow: hidden; }
.s3 .footer-geometric { position: absolute; top: 0; left: 0; right: 0; height: 4px; background: linear-gradient(90deg, #FF6D00, #E65100, #FF6D00); }
.s3 .footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1.5fr; gap: 40px; }
.s3 .footer-logo { margin-bottom: 16px; }
.s3 .footer-logo .logo-icon { color: #FF6D00; font-size: 24px; }
.s3 .footer-logo .logo-text { color: #fff; font-size: 20px; }
.s3 .footer-about p { font-size: 14px; line-height: 1.7; margin-bottom: 16px; }
.s3 .footer-social { display: flex; gap: 10px; }
.s3 .footer-social a { width: 36px; height: 36px; background: rgba(255,255,255,0.08); border-radius: 50%; display: flex; align-items: center; justify-content: center; color: #aaa; transition: all 0.3s; text-decoration: none; }
.s3 .footer-social a:hover { background: #FF6D00; color: #fff; }
.s3 .footer-col h4 { color: #fff; font-size: 16px; margin-bottom: 20px; position: relative; padding-bottom: 12px; }
.s3 .footer-col h4::after { content: ''; position: absolute; bottom: 0; left: 0; width: 30px; height: 3px; background: #FF6D00; border-radius: 2px; }
.s3 .footer-col ul { list-style: none; padding: 0; margin: 0; }
.s3 .footer-col ul li { margin-bottom: 8px; }
.s3 .footer-col ul a { color: #aaa; font-size: 14px; text-decoration: none; }
.s3 .footer-col ul a:hover { color: #FF6D00; padding-left: 4px; }
.s3 .footer-contact { list-style: none; padding: 0; margin: 0; }
.s3 .footer-contact li { display: flex; gap: 10px; align-items: flex-start; margin-bottom: 12px; font-size: 13px; }
.s3 .footer-contact i { color: #FF6D00; margin-top: 4px; }
.s3 .footer-bottom { margin-top: 40px; padding: 20px 0; border-top: 1px solid rgba(255,255,255,0.08); text-align: center; font-size: 13px; }
.s3 [data-animate] { opacity: 0; transform: translateY(30px); transition: opacity 0.7s ease, transform 0.7s ease; }
.s3 [data-animate="slide-right"] { transform: translateX(-40px); }
.s3 [data-animate="slide-left"] { transform: translateX(40px); }
.s3 [data-animate].animated { opacity: 1; transform: translate(0, 0); }

/* Quote Form Section */
.s3 .quote-form-section { background: linear-gradient(135deg, #FAFAFA 0%, #FFF3E0 100%); padding: 80px 0; position: relative; }
.s3 .quote-form-wrapper { max-width: 900px; margin: 0 auto; background: #fff; border-radius: 20px; padding: 50px; box-shadow: 0 10px 40px rgba(0,0,0,0.08); }
.s3 .quote-form-header { text-align: center; margin-bottom: 40px; }
.s3 .quote-form-header h2 { font-size: 28px; color: #212121; margin-top: 16px; margin-bottom: 16px; }
.s3 .quote-form { display: flex; flex-direction: column; gap: 24px; }
.s3 .form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.s3 .form-group { display: flex; flex-direction: column; gap: 8px; }
.s3 .form-group.full-width { grid-column: 1 / -1; }
.s3 .form-group label { font-size: 14px; font-weight: 600; color: #333; font-family: 'Montserrat', sans-serif; }
.s3 .form-group .required { color: #FF6D00; font-weight: 700; margin-left: 4px; }
.s3 .form-group input, .s3 .form-group select, .s3 .form-group textarea { 
    padding: 14px 18px; 
    border: 2px solid #E0E0E0; 
    border-radius: 10px; 
    font-size: 15px; 
    font-family: 'Nunito', sans-serif;
    transition: all 0.3s; 
    background: #FAFAFA;
    color: #212121;
}
.s3 .form-group input:focus, .s3 .form-group select:focus, .s3 .form-group textarea:focus { 
    outline: none; 
    border-color: #FF6D00; 
    background: #fff;
    box-shadow: 0 0 0 4px rgba(255,109,0,0.1);
}
.s3 .form-group input::placeholder, .s3 .form-group textarea::placeholder { 
    color: #999; 
}
.s3 .form-group select { 
    cursor: pointer; 
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%23FF6D00' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10l-5 5z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 40px;
}
.s3 .form-group textarea { 
    resize: vertical; 
    min-height: 120px;
}
.s3 .form-submit { 
    text-align: center; 
    margin-top: 16px;
}
.s3 .form-submit button { 
    min-width: 200px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}
.s3 .form-submit button i { 
    font-size: 16px;
}

/* ========================================
   返回顶部按钮 - 统一样式
   ======================================== */
.back-to-top {
    position: fixed;
    right: 30px;
    bottom: 30px;
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, #FF6D00 0%, #E65100 100%);
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(255, 109, 0, 0.4);
    z-index: 9999;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px) scale(0.8);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 2px solid rgba(255, 255, 255, 0.2);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.back-to-top:hover {
    transform: translateY(-5px) scale(1.1);
    box-shadow: 0 8px 30px rgba(255, 109, 0, 0.6);
    background: linear-gradient(135deg, #FF8F00 0%, #FF6D00 100%);
}

.back-to-top:active,
.back-to-top.clicked {
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 6px 25px rgba(255, 109, 0, 0.5);
}

.back-to-top i {
    font-size: 20px;
    color: white;
    line-height: 1;
    transition: transform 0.3s ease;
}

.back-to-top:hover i {
    transform: translateY(-2px);
}

.back-to-top-text {
    font-size: 10px;
    font-weight: 700;
    color: white;
    letter-spacing: 0.5px;
    line-height: 1;
}

/* 脉冲动画效果 */
.back-to-top::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background: linear-gradient(135deg, #FF6D00 0%, #E65100 100%);
    z-index: -1;
    animation: backToTopPulse 2s ease-in-out infinite;
}

@keyframes backToTopPulse {
    0%, 100% {
        transform: scale(1);
        opacity: 0;
    }
    50% {
        transform: scale(1.3);
        opacity: 0.3;
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .back-to-top {
        right: 20px;
        bottom: 20px;
        width: 50px;
        height: 50px;
    }
    
    .back-to-top i {
        font-size: 18px;
    }
    
    .back-to-top-text {
        font-size: 9px;
    }
}

@media (max-width: 480px) {
    .back-to-top {
        right: 15px;
        bottom: 15px;
        width: 46px;
        height: 46px;
    }
    
    .back-to-top i {
        font-size: 16px;
    }
    
    .back-to-top-text {
        font-size: 8px;
    }
}

/* 深色主题适配 */
.s1 .back-to-top,
.s2 .back-to-top {
    background: linear-gradient(135deg, #FF6D00 0%, #E65100 100%);
    box-shadow: 0 4px 20px rgba(255, 109, 0, 0.4);
}

.s3 .back-to-top {
    background: linear-gradient(135deg, #FF6D00 0%, #E65100 100%);
    box-shadow: 0 4px 20px rgba(255, 109, 0, 0.4);
}

/* Responsive adjustments for form */
@media (max-width: 768px) {
    .s3 .quote-form-wrapper { padding: 30px 20px; }
    .s3 .form-row { grid-template-columns: 1fr; }
    .s3 .quote-form-header h2 { font-size: 24px; }
}