/* CSS Reset & Variable Definition - Laser Iridescent Theme (浅色镭射幻彩风) */
        :root {
            --bg-main: #f8fafc;
            --bg-card: rgba(255, 255, 255, 0.85);
            --text-primary: #0f172a;
            --text-secondary: #475569;
            --text-muted: #64748b;
            --brand-primary: #6366f1;
            --brand-secondary: #a855f7;
            --brand-accent: #ec4899;
            --gradient-laser: linear-gradient(135deg, #6366f1 0%, #a855f7 38%, #ec4899 70%, #06b6d4 100%);
            --gradient-subtle: linear-gradient(135deg, rgba(99, 102, 241, 0.08) 0%, rgba(168, 85, 247, 0.08) 50%, rgba(6, 182, 212, 0.08) 100%);
            --border-iridescent: linear-gradient(135deg, rgba(99, 102, 241, 0.4), rgba(236, 72, 153, 0.4), rgba(6, 182, 212, 0.4));
            --shadow-laser: 0 10px 30px -10px rgba(168, 85, 247, 0.25);
            --shadow-card: 0 4px 20px rgba(15, 23, 42, 0.05);
            --radius-lg: 16px;
            --radius-md: 10px;
            --radius-sm: 6px;
            --container-max: 1200px;
        }

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

        html {
            scroll-behavior: smooth;
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            background-color: var(--bg-main);
            color: var(--text-primary);
            line-height: 1.6;
        }

        body {
            overflow-x: hidden;
            background: radial-gradient(circle at 20% 10%, rgba(99, 102, 241, 0.06) 0%, transparent 40%),
                        radial-gradient(circle at 80% 50%, rgba(236, 72, 153, 0.06) 0%, transparent 40%),
                        radial-gradient(circle at 50% 90%, rgba(6, 182, 212, 0.06) 0%, transparent 40%);
            background-attachment: fixed;
        }

        /* Container Layout System */
        .container {
            width: 100%;
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 20px;
        }

        section {
            padding: 80px 0;
            position: relative;
        }

        /* Nav Bar - Strict gap: 0 requirement */
        .site-header {
            position: sticky;
            top: 0;
            z-index: 1000;
            background: rgba(255, 255, 255, 0.9);
            backdrop-filter: blur(16px);
            border-bottom: 1px solid rgba(226, 232, 240, 0.8);
            box-shadow: 0 2px 10px rgba(0,0,0,0.03);
        }

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

        .brand-logo-wrap {
            display: flex;
            align-items: center;
            gap: 12px;
            text-decoration: none;
        }

        .ai-page-logo {
            height: 40px;
            width: auto;
            display: block;
        }

        .brand-title {
            font-size: 1.25rem;
            font-weight: 700;
            background: var(--gradient-laser);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .nav-links {
            display: flex;
            align-items: center;
            gap: 0; /* STRICT REQUIREMENT */
            list-style: none;
        }

        .nav-links li a {
            display: inline-block;
            padding: 8px 12px;
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 0.9rem;
            font-weight: 500;
            transition: all 0.2s ease;
        }

        .nav-links li a:hover {
            color: var(--brand-primary);
            background: rgba(99, 102, 241, 0.05);
            border-radius: var(--radius-sm);
        }

        .nav-cta-btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 8px 18px;
            background: var(--gradient-laser);
            color: #fff !important;
            border-radius: 30px;
            font-weight: 600;
            font-size: 0.9rem;
            text-decoration: none;
            box-shadow: 0 4px 12px rgba(168, 85, 247, 0.3);
            transition: transform 0.2s, box-shadow 0.2s;
        }

        .nav-cta-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 18px rgba(168, 85, 247, 0.4);
        }

        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            font-size: 1.5rem;
            color: var(--text-primary);
            cursor: pointer;
        }

        /* Section Title Styles */
        .section-header {
            text-align: center;
            margin-bottom: 50px;
        }

        .section-tag {
            display: inline-block;
            padding: 4px 14px;
            background: rgba(168, 85, 247, 0.1);
            color: var(--brand-secondary);
            border-radius: 20px;
            font-size: 0.85rem;
            font-weight: 600;
            margin-bottom: 12px;
            border: 1px solid rgba(168, 85, 247, 0.2);
        }

        .section-title {
            font-size: 2rem;
            font-weight: 800;
            color: var(--text-primary);
            letter-spacing: -0.5px;
        }

        .section-subtitle {
            margin-top: 10px;
            color: var(--text-secondary);
            font-size: 1rem;
            max-width: 650px;
            margin-left: auto;
            margin-right: auto;
        }

        /* Laser Iridescent Card Styling */
        .laser-card {
            background: var(--bg-card);
            border: 1px solid rgba(226, 232, 240, 0.9);
            border-radius: var(--radius-lg);
            padding: 28px;
            box-shadow: var(--shadow-card);
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
            backdrop-filter: blur(10px);
        }

        .laser-card::before {
            content: '';
            position: absolute;
            top: 0; left: 0; right: 0; height: 3px;
            background: var(--gradient-laser);
            opacity: 0.7;
            transition: opacity 0.3s;
        }

        .laser-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-laser);
            border-color: rgba(168, 85, 247, 0.4);
        }

        .laser-card:hover::before {
            opacity: 1;
        }

        /* HERO SECTION - NO IMAGES ALLOWED */
        .hero-section {
            padding: 90px 0 70px;
            text-align: center;
            background: radial-gradient(ellipse at top, rgba(99, 102, 241, 0.12), transparent 70%);
        }

        .hero-badge-group {
            display: flex;
            justify-content: center;
            gap: 10px;
            flex-wrap: wrap;
            margin-bottom: 24px;
        }

        .hero-pill {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 6px 16px;
            background: #ffffff;
            border: 1px solid rgba(99, 102, 241, 0.2);
            border-radius: 30px;
            font-size: 0.85rem;
            color: var(--brand-primary);
            font-weight: 600;
            box-shadow: 0 2px 8px rgba(0,0,0,0.04);
        }

        .hero-title {
            font-size: 2.5rem;
            font-weight: 900;
            line-height: 1.25;
            color: var(--text-primary);
            margin-bottom: 20px;
            max-width: 900px;
            margin-left: auto;
            margin-right: auto;
        }

        .hero-title-highlight {
            background: var(--gradient-laser);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .hero-desc {
            font-size: 1.15rem;
            color: var(--text-secondary);
            max-width: 760px;
            margin: 0 auto 36px;
        }

        .hero-actions {
            display: flex;
            justify-content: center;
            align-items: center;
            gap: 16px;
            flex-wrap: wrap;
            margin-bottom: 50px;
        }

        .btn-primary {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 14px 32px;
            background: var(--gradient-laser);
            color: #fff;
            font-size: 1.05rem;
            font-weight: 700;
            border-radius: 30px;
            text-decoration: none;
            box-shadow: 0 8px 24px rgba(168, 85, 247, 0.35);
            transition: all 0.3s ease;
            border: none;
            cursor: pointer;
        }

        .btn-primary:hover {
            transform: translateY(-2px) scale(1.02);
            box-shadow: 0 12px 30px rgba(168, 85, 247, 0.45);
        }

        .btn-secondary {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 14px 32px;
            background: #ffffff;
            color: var(--text-primary);
            font-size: 1.05rem;
            font-weight: 700;
            border-radius: 30px;
            text-decoration: none;
            border: 2px solid rgba(226, 232, 240, 1);
            box-shadow: 0 4px 12px rgba(0,0,0,0.03);
            transition: all 0.3s ease;
        }

        .btn-secondary:hover {
            border-color: var(--brand-primary);
            color: var(--brand-primary);
            transform: translateY(-2px);
        }

        .hero-stats-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 20px;
            max-width: 950px;
            margin: 0 auto;
        }

        .stat-card {
            background: rgba(255, 255, 255, 0.9);
            border: 1px solid rgba(226, 232, 240, 0.8);
            border-radius: var(--radius-md);
            padding: 20px;
            text-align: center;
        }

        .stat-number {
            font-size: 2rem;
            font-weight: 800;
            background: var(--gradient-laser);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .stat-label {
            font-size: 0.85rem;
            color: var(--text-muted);
            margin-top: 4px;
        }

        /* General Grids */
        .grid-3 {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
            gap: 24px;
        }

        .grid-4 {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 20px;
        }

        .grid-2 {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
            gap: 30px;
        }

        /* Feature Icons */
        .icon-box {
            width: 48px;
            height: 48px;
            border-radius: 12px;
            background: var(--gradient-subtle);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            margin-bottom: 16px;
            color: var(--brand-primary);
            border: 1px solid rgba(99, 102, 241, 0.15);
        }

        /* Scenarios Styling */
        .scenario-item {
            padding: 20px;
            border-radius: var(--radius-md);
            background: #ffffff;
            border: 1px solid #e2e8f0;
            transition: all 0.2s;
        }

        .scenario-item:hover {
            border-color: var(--brand-secondary);
            box-shadow: 0 6px 16px rgba(168, 85, 247, 0.1);
        }

        .scenario-title {
            font-size: 1.05rem;
            font-weight: 700;
            margin-bottom: 8px;
            color: var(--text-primary);
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .scenario-desc {
            font-size: 0.88rem;
            color: var(--text-secondary);
        }

        /* Model Tag Cloud */
        .tag-cloud {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            justify-content: center;
            margin-top: 20px;
        }

        .model-chip {
            padding: 6px 14px;
            background: #ffffff;
            border: 1px solid #e2e8f0;
            border-radius: 20px;
            font-size: 0.85rem;
            font-weight: 600;
            color: var(--text-secondary);
            box-shadow: 0 2px 4px rgba(0,0,0,0.02);
            transition: all 0.2s;
        }

        .model-chip:hover {
            background: var(--gradient-laser);
            color: #ffffff;
            border-color: transparent;
        }

        /* Review / Comparison Table */
        .comparison-table-wrap {
            overflow-x: auto;
            background: #ffffff;
            border-radius: var(--radius-lg);
            box-shadow: var(--shadow-card);
            border: 1px solid #e2e8f0;
        }

        table.comparison-table {
            width: 100%;
            border-collapse: collapse;
            text-align: left;
            min-width: 650px;
        }

        table.comparison-table th, table.comparison-table td {
            padding: 16px 20px;
            border-bottom: 1px solid #e2e8f0;
        }

        table.comparison-table th {
            background: #f8fafc;
            font-weight: 700;
            color: var(--text-primary);
        }

        .highlight-col {
            background: rgba(99, 102, 241, 0.04);
            font-weight: 700;
            color: var(--brand-primary);
        }

        /* Rating Highlight Box */
        .rating-box {
            text-align: center;
            background: var(--gradient-subtle);
            padding: 30px;
            border-radius: var(--radius-lg);
            border: 1px solid rgba(168, 85, 247, 0.3);
            margin-bottom: 30px;
        }

        .score-val {
            font-size: 3.5rem;
            font-weight: 900;
            background: var(--gradient-laser);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            line-height: 1;
        }

        .stars {
            color: #f59e0b;
            font-size: 1.4rem;
            margin: 8px 0;
        }

        /* Testimonials */
        .testimonial-card {
            background: #ffffff;
            border: 1px solid #e2e8f0;
            border-radius: var(--radius-lg);
            padding: 24px;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
        }

        .user-info {
            display: flex;
            align-items: center;
            gap: 12px;
            margin-top: 16px;
        }

        .avatar-placeholder {
            width: 44px;
            height: 44px;
            border-radius: 50%;
            background: var(--gradient-laser);
            color: #fff;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
        }

        /* Process Steps */
        .step-card {
            position: relative;
            padding: 24px;
            background: #ffffff;
            border-radius: var(--radius-md);
            border: 1px solid #e2e8f0;
        }

        .step-num {
            font-size: 2rem;
            font-weight: 900;
            color: rgba(99, 102, 241, 0.2);
            position: absolute;
            top: 16px;
            right: 20px;
        }

        /* FAQ Accordion */
        .faq-item {
            background: #ffffff;
            border: 1px solid #e2e8f0;
            border-radius: var(--radius-md);
            margin-bottom: 12px;
            overflow: hidden;
        }

        .faq-question {
            width: 100%;
            padding: 18px 24px;
            text-align: left;
            background: none;
            border: none;
            font-size: 1rem;
            font-weight: 700;
            color: var(--text-primary);
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .faq-answer {
            padding: 0 24px 18px;
            color: var(--text-secondary);
            font-size: 0.95rem;
            display: none;
            border-top: 1px dashed #f1f5f9;
            padding-top: 14px;
        }

        .faq-item.active .faq-answer {
            display: block;
        }

        .faq-toggle-icon {
            font-size: 1.2rem;
            transition: transform 0.3s;
        }

        .faq-item.active .faq-toggle-icon {
            transform: rotate(45deg);
        }

        /* Form Styles */
        .contact-form {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 16px;
        }

        .form-full {
            grid-column: span 2;
        }

        .form-group label {
            display: block;
            font-size: 0.88rem;
            font-weight: 600;
            margin-bottom: 6px;
            color: var(--text-primary);
        }

        .form-input, .form-select, .form-textarea {
            width: 100%;
            padding: 12px 16px;
            border: 1px solid #cbd5e1;
            border-radius: var(--radius-sm);
            font-size: 0.95rem;
            background: #ffffff;
            outline: none;
            transition: border-color 0.2s;
        }

        .form-input:focus, .form-select:focus, .form-textarea:focus {
            border-color: var(--brand-primary);
            box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
        }

        /* Articles & Links */
        .article-link-list {
            list-style: none;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 12px;
        }

        .article-link-list li a {
            display: block;
            padding: 14px 18px;
            background: #ffffff;
            border: 1px solid #e2e8f0;
            border-radius: var(--radius-sm);
            color: var(--text-primary);
            text-decoration: none;
            font-weight: 600;
            transition: all 0.2s;
        }

        .article-link-list li a:hover {
            color: var(--brand-primary);
            border-color: var(--brand-primary);
            transform: translateX(4px);
        }

        /* Footer */
        .site-footer {
            background: #0f172a;
            color: #94a3b8;
            padding: 60px 0 30px;
            font-size: 0.9rem;
        }

        .footer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 40px;
            margin-bottom: 40px;
        }

        .footer-col h4 {
            color: #ffffff;
            font-size: 1.05rem;
            margin-bottom: 16px;
        }

        .footer-links {
            list-style: none;
        }

        .footer-links li {
            margin-bottom: 10px;
        }

        .footer-links a {
            color: #94a3b8;
            text-decoration: none;
            transition: color 0.2s;
        }

        .footer-links a:hover {
            color: #ffffff;
        }

        .friendship-links {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            padding-top: 20px;
            border-top: 1px solid #1e293b;
            margin-top: 30px;
        }

        .friendship-links a {
            color: #64748b;
            text-decoration: none;
            font-size: 0.85rem;
        }

        .friendship-links a:hover {
            color: #38bdf8;
        }

        .footer-bottom {
            text-align: center;
            padding-top: 30px;
            border-top: 1px solid #1e293b;
            color: #64748b;
            font-size: 0.85rem;
        }

        /* Floating Contact Widget */
        .floating-contact {
            position: fixed;
            bottom: 30px;
            right: 30px;
            z-index: 999;
            display: flex;
            flex-direction: column;
            gap: 10px;
        }

        .float-btn {
            width: 50px;
            height: 50px;
            border-radius: 50%;
            background: var(--gradient-laser);
            color: #ffffff;
            display: flex;
            align-items: center;
            justify-content: center;
            box-shadow: 0 4px 15px rgba(0,0,0,0.2);
            text-decoration: none;
            font-size: 1.2rem;
            transition: transform 0.2s;
        }

        .float-btn:hover {
            transform: scale(1.1);
        }

        /* Responsive Breakpoints */
        @media (max-width: 992px) {
            .nav-links {
                display: none;
            }
            .mobile-menu-btn {
                display: block;
            }
            .hero-title {
                font-size: 2rem;
            }
            .contact-form {
                grid-template-columns: 1fr;
            }
            .form-full {
                grid-column: span 1;
            }
        }