/* =============================================
   MiteShield - 防螨地毯网站模板
   作者: AI 全栈工程师
   日期: 2024
   ============================================= */

/* --- CSS Variables (Design Tokens) --- */
:root {
    /* Colors */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-secondary: #10b981;
    --color-accent: #f59e0b;
    --color-bg: #f8fafc;
    --color-white: #ffffff;
    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-text-muted: #94a3b8;
    --color-border: #e2e8f0;
    --color-card-bg: #ffffff;
    --color-card-shadow: rgba(0, 0, 0, 0.05);
    --color-card-shadow-hover: rgba(37, 99, 235, 0.15);
    --color-success: #10b981;
    --color-error: #ef4444;
    --color-gradient-start: #eff6ff;
    --color-gradient-end: #f0fdf4;

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-heading: 'Playfair Display', 'Times New Roman', serif;

    /* Spacing */
    --section-padding: 5rem 0;
    --container-max-width: 1200px;
    --grid-gap: 2rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.75rem;
    --radius-lg: 1.5rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: var(--font-primary);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

ul {
    list-style: none;
}

/* --- Container --- */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.75rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 0.95rem;
    line-height: 1.5;
    cursor: pointer;
    transition: all var(--transition-base);
    border: 2px solid transparent;
    text-align: center;
    white-space: nowrap;
}

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

.btn-primary:hover,
.btn-primary:focus-visible {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-outline {
    background: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-outline:hover,
.btn-outline:focus-visible {
    background: var(--color-primary);
    color: var(--color-white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-sm {
    padding: 0.5rem 1.25rem;
    font-size: 0.875rem;
}

.btn-lg {
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
}

.full-width {
    width: 100%;
}

/* --- Badge --- */
.badge {
    display: inline-block;
    background: linear-gradient(135deg, #dbeafe, #ede9fe);
    color: var(--color-primary-dark);
    font-weight: 600;
    font-size: 0.8rem;
    padding: 0.35rem 1rem;
    border-radius: var(--radius-full);
    margin-bottom: 1rem;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

/* --- Section Header --- */
.section-header {
    text-align: center;
    max-width: 650px;
    margin: 0 auto 3rem auto;
}

.section-header h2 {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-text);
    line-height: 1.3;
    margin-bottom: 1rem;
}

.section-header p {
    color: var(--color-text-light);
    font-size: 1.1rem;
}

/* =============================================
   Header & Navigation
   ============================================= */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
    transition: background var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.site-header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow-md);
    border-bottom-color: var(--color-border);
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo i {
    font-size: 1.8rem;
    color: var(--color-primary);
}

.logo span {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2.5rem;
}

.nav-link {
    font-weight: 500;
    color: var(--color-text-light);
    position: relative;
    padding: 0.25rem 0;
    transition: color var(--transition-fast);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width var(--transition-base);
    border-radius: 2px;
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-text);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.bar {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--color-text);
    border-radius: 3px;
    transition: all var(--transition-fast);
}

.hamburger.active .bar:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.hamburger.active .bar:nth-child(2) {
    opacity: 0;
}

.hamburger.active .bar:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* =============================================
   Hero Section
   ============================================= */
.hero {
    padding: 8rem 0 5rem 0;
    background: linear-gradient(135deg, var(--color-gradient-start) 0%, var(--color-gradient-end) 100%);
    min-height: 80vh;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-family: var(--font-heading);
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.2;
    margin: 1.5rem 0 1.5rem 0;
    color: var(--color-text);
}

.hero-content p {
    font-size: 1.15rem;
    color: var(--color-text-light);
    margin-bottom: 2rem;
    max-width: 500px;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 3rem;
}

.hero-stats {
    display: flex;
    gap: 2.5rem;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.2;
}

.stat-suffix {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--color-primary);
}

.stat-label {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-top: 0.25rem;
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-image img {
    width: 100%;
    max-width: 500px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-15px); }
}

/* =============================================
   Features Section
   ============================================= */
.features {
    padding: var(--section-padding);
    background: var(--color-white);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--grid-gap);
}

.feature-card {
    background: var(--color-card-bg);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary-light);
}

.feature-icon {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #dbeafe, #ede9fe);
    border-radius: var(--radius-md);
    margin-bottom: 1.5rem;
}

.feature-icon i {
    font-size: 1.8rem;
    color: var(--color-primary);
}

.feature-card h3 {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    margin-bottom: 0.75rem;
}

.feature-card p {
    color: var(--color-text-light);
    font-size: 0.95rem;
}

/* =============================================
   Products Section
   ============================================= */
.products {
    padding: var(--section-padding);
    background: var(--color-bg);
}

.product-filters {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 2.5rem;
}

.filter-btn {
    padding: 0.6rem 1.5rem;
    border: 1px solid var(--color-border);
    background: var(--color-white);
    border-radius: var(--radius-full);
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--color-text-light);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.filter-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background: #eff6ff;
}

.filter-btn.active {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--grid-gap);
}

.product-card {
    background: var(--color-card-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    overflow: hidden;
    transition: all var(--transition-base);
    cursor: pointer;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.product-image {
    width: 100%;
    height: 220px;
    object-fit: cover;
    background: #f1f5f9;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: var(--color-primary-light);
}

.product-info {
    padding: 1.5rem;
}

.product-category {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}

.product-info h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.product-info p {
    color: var(--color-text-light);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.product-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.product-price {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--color-primary);
}

.product-rating {
    font-size: 0.85rem;
    color: var(--color-accent);
}

.product-rating span {
    color: var(--color-text-muted);
    margin-left: 0.25rem;
}

/* =============================================
   Testimonials Section
   ============================================= */
.testimonials {
    padding: var(--section-padding);
    background: var(--color-white);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--grid-gap);
}

.testimonial-card {
    background: var(--color-bg);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

.testimonial-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.testimonial-card.featured {
    border-color: var(--color-primary-light);
    background: linear-gradient(135deg, #eff6ff, #f0fdf4);
    position: relative;
}

.testimonial-card.featured::before {
    content: '\201C';
    position: absolute;
    top: -10px;
    left: 20px;
    font-size: 5rem;
    color: var(--color-primary-light);
    opacity: 0.3;
    font-family: var(--font-heading);
    line-height: 1;
}

.rating {
    color: var(--color-accent);
    margin-bottom: 1rem;
}

.testimonial-card p {
    color: var(--color-text);
    font-size: 1rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
    font-style: italic;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    object-fit: cover;
}

.user-info strong {
    display: block;
    font-weight: 600;
    color: var(--color-text);
}

.user-info span {
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* =============================================
   CTA Section
   ============================================= */
.cta {
    padding: 5rem 0;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    text-align: center;
    color: var(--color-white);
}

.cta h2 {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.cta p {
    font-size: 1.15rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

.cta .btn:hover {
    background: transparent;
    color: var(--color-white);
}

/* =============================================
   Contact Section
   ============================================= */
.contact {
    padding: var(--section-padding);
    background: var(--color-bg);
}

.contact-wrapper {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 3rem;
    align-items: start;
}

.contact-form {
    background: var(--color-white);
    padding: 2.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

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

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--color-text);
    font-size: 0.95rem;
}

.required {
    color: var(--color-error);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-primary);
    font-size: 0.95rem;
    color: var(--color-text);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
    background: var(--color-bg);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
    background: var(--color-white);
}

.form-group input.error,
.form-group textarea.error {
    border-color: var(--color-error);
}

.error-message {
    display: none;
    font-size: 0.85rem;
    color: var(--color-error);
    margin-top: 0.25rem;
}

.error-message.visible {
    display: block;
}

.form-success {
    display: none;
    text-align: center;
    padding: 1rem;
    background: #ecfdf5;
    color: var(--color-success);
    border-radius: var(--radius-md);
    font-weight: 500;
    margin-top: 1rem;
}

.form-success.visible {
    display: block;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.info-card {
    background: var(--color-white);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: all var(--transition-fast);
}

.info-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--color-primary-light);
}

.info-card i {
    font-size: 1.5rem;
    color: var(--color-primary);
    margin-bottom: 0.75rem;
}

.info-card h4 {
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.info-card p {
    color: var(--color-text-light);
    font-size: 0.95rem;
}

.info-card small {
    color: var(--color-text-muted);
    font-size: 0.8rem;
}

/* =============================================
   Footer
   ============================================= */
.site-footer {
    background: var(--color-text);
    color: #cbd5e1;
    padding: 4rem 0 0 0;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 3rem;
    padding-bottom: 3rem;
    border-bottom: 1px solid #334155;
}

.footer-brand .logo i,
.footer-brand .logo span {
    color: var(--color-white);
}

.footer-brand p {
    margin: 1rem 0 1.5rem 0;
    font-size: 0.9rem;
    line-height: 1.8;
    max-width: 300px;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #334155;
    border-radius: 50%;
    color: #cbd5e1;
    transition: all var(--transition-fast);
}

.social-links a:hover {
    background: var(--color-primary);
    color: var(--color-white);
    transform: translateY(-2px);
}

.footer-links h4 {
    color: var(--color-white);
    font-weight: 600;
    margin-bottom: 1.25rem;
}

.footer-links ul li {
    margin-bottom: 0.75rem;
}

.footer-links ul a {
    color: #94a3b8;
    font-size: 0.9rem;
    transition: color var(--transition-fast);
}

.footer-links ul a:hover {
    color: var(--color-primary-light);
}

.footer-bottom {
    padding: 1.5rem 0;
    text-align: center;
    font-size: 0.85rem;
    color: #64748b;
}

/* =============================================
   Back to Top
   ============================================= */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    color: var(--color-white);
    border: none;
    border-radius: 50%;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition-base);
    z-index: 999;
}

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

.back-to-top:hover {
    background: var(--color-primary-dark);
    transform: translateY(-3px);
}

/* =============================================
   Responsive Design
   ============================================= */

/* Tablet */
@media (max-width: 1024px) {
    .hero-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
    }

    .hero-content p {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-buttons {
        justify-content: center;
    }

    .hero-stats {
        justify-content: center;
    }

    .hero-image {
        order: -1;
    }

    .hero-image img {
        max-width: 400px;
    }

    .contact-wrapper {
        grid-template-columns: 1fr;
    }
}

/* Mobile */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--color-white);
        flex-direction: column;
        padding: 2rem;
        gap: 1.5rem;
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
        border-bottom: 1px solid var(--color-border);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .hamburger {
        display: flex;
    }

    .hero {
        padding: 6rem 0 3rem 0;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

    .hero-stats {
        flex-wrap: wrap;
        gap: 1.5rem;
    }

    .section-header h2 {
        font-size: 2rem;
    }

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

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

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

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .contact-form {
        padding: 1.5rem;
    }

    .back-to-top {
        bottom: 1rem;
        right: 1rem;
        width: 42px;
        height: 42px;
        font-size: 1rem;
    }
}

/* Small Mobile */
@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 2rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .hero-buttons .btn {
        width: 100%;
    }

    .stat-number {
        font-size: 1.8rem;
    }

    .product-filters {
        gap: 0.5rem;
    }

    .filter-btn {
        padding: 0.4rem 1rem;
        font-size: 0.8rem;
    }
}