/* CSS Reset & Variable Design - 多彩涂鸦风格 (Colorful Graffiti Pop Art) */
        :root {
            --bg-color: #faf8f5;
            --main-text: #18181b;
            --accent-yellow: #ffe600;
            --accent-pink: #ff3366;
            --accent-cyan: #00e5ff;
            --accent-purple: #9d4edd;
            --accent-green: #10b981;
            --card-bg: #ffffff;
            --border-dark: #18181b;
            --border-width: 3px;
            --shadow-doodle: 5px 5px 0px #18181b;
            --shadow-doodle-lg: 8px 8px 0px #18181b;
            --shadow-hover: 9px 9px 0px #18181b;
            --radius-doodle: 16px;
            --container-width: 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-color);
            color: var(--main-text);
            line-height: 1.6;
        }

        body {
            overflow-x: hidden;
            background: var(--bg-color);
            background-image: 
                radial-gradient(var(--border-dark) 1px, transparent 0);
            background-size: 24px 24px;
            background-color: #faf8f5;
        }

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

        /* Common Elements & Typography */
        h1, h2, h3, h4 {
            color: var(--main-text);
            font-weight: 900;
            line-height: 1.25;
        }

        h2.section-title {
            font-size: 2.2rem;
            text-align: center;
            margin-bottom: 12px;
            display: inline-block;
            background: var(--accent-yellow);
            padding: 6px 18px;
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            box-shadow: var(--shadow-doodle);
            transform: rotate(-1deg);
        }

        .section-title-wrap {
            text-align: center;
            margin-bottom: 40px;
        }

        .section-subtitle {
            color: #52525b;
            font-size: 1.05rem;
            margin-top: 10px;
            font-weight: 600;
        }

        p {
            color: #27272a;
        }

        a {
            color: var(--main-text);
            text-decoration: none;
        }

        /* Graffiti Doodle Badge & Buttons */
        .badge {
            display: inline-block;
            padding: 4px 12px;
            font-weight: 800;
            font-size: 0.85rem;
            border-radius: 20px;
            border: 2px solid var(--border-dark);
            background: #fff;
            box-shadow: 2px 2px 0px var(--border-dark);
            margin-right: 6px;
            margin-bottom: 6px;
        }

        .badge-yellow { background: var(--accent-yellow); }
        .badge-pink { background: var(--accent-pink); color: #fff; }
        .badge-cyan { background: var(--accent-cyan); }
        .badge-purple { background: var(--accent-purple); color: #fff; }
        .badge-green { background: var(--accent-green); color: #fff; }

        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 12px 28px;
            font-weight: 800;
            font-size: 1rem;
            border: var(--border-width) solid var(--border-dark);
            border-radius: 12px;
            cursor: pointer;
            transition: all 0.2s ease;
            box-shadow: var(--shadow-doodle);
            text-decoration: none;
        }

        .btn-primary {
            background: var(--accent-yellow);
            color: var(--main-text);
        }

        .btn-primary:hover {
            transform: translate(-3px, -3px);
            box-shadow: var(--shadow-hover);
            background: #ffd000;
        }

        .btn-pink {
            background: var(--accent-pink);
            color: #fff;
        }

        .btn-pink:hover {
            transform: translate(-3px, -3px);
            box-shadow: var(--shadow-hover);
        }

        .btn-cyan {
            background: var(--accent-cyan);
            color: var(--main-text);
        }

        /* Header Navigation */
        header {
            position: sticky;
            top: 0;
            z-index: 1000;
            background: #ffffff;
            border-bottom: var(--border-width) solid var(--border-dark);
            padding: 12px 0;
        }

        .nav-container {
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

        .brand-logo-area {
            display: flex;
            align-items: center;
            gap: 12px;
        }

        .ai-page-logo {
            max-height: 42px;
            width: auto;
            display: block;
        }

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

        .nav-links li a {
            padding: 8px 14px;
            font-weight: 700;
            font-size: 0.92rem;
            color: var(--main-text);
            border-radius: 8px;
            transition: background 0.2s;
            display: inline-block;
        }

        .nav-links li a:hover {
            background: var(--accent-yellow);
            border: 2px solid var(--border-dark);
            box-shadow: 2px 2px 0px var(--border-dark);
            padding: 6px 12px;
        }

        .nav-actions {
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .mobile-menu-btn {
            display: none;
            background: var(--accent-yellow);
            border: var(--border-width) solid var(--border-dark);
            padding: 6px 12px;
            font-weight: 800;
            border-radius: 8px;
            cursor: pointer;
        }

        /* Hero Section - NO IMAGES STRICT RULE */
        .hero-section {
            padding: 60px 0 50px;
            position: relative;
            background: linear-gradient(135deg, #fff 0%, #fff7d6 100%);
            border-bottom: var(--border-width) solid var(--border-dark);
        }

        .hero-inner {
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
            max-width: 900px;
            margin: 0 auto;
        }

        .hero-tag {
            background: var(--accent-pink);
            color: #fff;
            padding: 6px 16px;
            border-radius: 30px;
            border: var(--border-width) solid var(--border-dark);
            box-shadow: 3px 3px 0px var(--border-dark);
            font-weight: 900;
            font-size: 0.95rem;
            margin-bottom: 20px;
            transform: rotate(-1.5deg);
        }

        .hero-title {
            font-size: 2.8rem;
            margin-bottom: 20px;
            line-height: 1.2;
            letter-spacing: -0.5px;
        }

        .hero-title span {
            background: var(--accent-cyan);
            padding: 2px 10px;
            border: 2px solid var(--border-dark);
            border-radius: 8px;
            box-shadow: 3px 3px 0px var(--border-dark);
            display: inline-block;
        }

        .hero-desc {
            font-size: 1.2rem;
            color: #3f3f46;
            margin-bottom: 30px;
            font-weight: 600;
            max-width: 780px;
        }

        .hero-cta-group {
            display: flex;
            gap: 16px;
            flex-wrap: wrap;
            justify-content: center;
            margin-bottom: 35px;
        }

        .hero-features-bar {
            display: flex;
            gap: 12px;
            flex-wrap: wrap;
            justify-content: center;
        }

        /* Card System (Doodle Border & Shadow) */
        .grid-3 {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }

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

        .grid-2 {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 24px;
        }

        .doodle-card {
            background: var(--card-bg);
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            padding: 24px;
            box-shadow: var(--shadow-doodle);
            transition: transform 0.2s ease, box-shadow 0.2s ease;
            position: relative;
        }

        .doodle-card:hover {
            transform: translate(-3px, -3px);
            box-shadow: var(--shadow-hover);
        }

        .card-icon-box {
            width: 52px;
            height: 52px;
            border: var(--border-width) solid var(--border-dark);
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.6rem;
            font-weight: 900;
            margin-bottom: 16px;
            box-shadow: 3px 3px 0px var(--border-dark);
        }

        /* Section Layouts */
        .section-padding {
            padding: 60px 0;
            border-bottom: var(--border-width) solid var(--border-dark);
        }

        /* Stats Section */
        .stats-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 20px;
        }

        .stat-card {
            text-align: center;
            background: #fff;
            padding: 24px;
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            box-shadow: var(--shadow-doodle);
        }

        .stat-card:nth-child(1) { background: #fffbe6; }
        .stat-card:nth-child(2) { background: #e6f7ff; }
        .stat-card:nth-child(3) { background: #fff0f6; }
        .stat-card:nth-child(4) { background: #f6ffed; }

        .stat-num {
            font-size: 2.5rem;
            font-weight: 900;
            margin-bottom: 4px;
            color: var(--main-text);
        }

        .stat-label {
            font-weight: 700;
            font-size: 0.95rem;
            color: #52525b;
        }

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

        .model-pill {
            background: #fff;
            border: 2px solid var(--border-dark);
            padding: 6px 14px;
            border-radius: 20px;
            font-weight: 800;
            font-size: 0.9rem;
            box-shadow: 2px 2px 0px var(--border-dark);
        }

        /* Comparison Section */
        .rating-box {
            background: var(--accent-yellow);
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            padding: 20px;
            text-align: center;
            box-shadow: var(--shadow-doodle);
            margin-bottom: 30px;
        }

        .rating-score {
            font-size: 3rem;
            font-weight: 900;
            line-height: 1;
            margin: 8px 0;
        }

        .compare-table-wrapper {
            overflow-x: auto;
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            box-shadow: var(--shadow-doodle);
            background: #fff;
        }

        .compare-table {
            width: 100%;
            border-collapse: collapse;
            text-align: left;
        }

        .compare-table th, .compare-table td {
            padding: 16px 20px;
            border-bottom: 2px solid var(--border-dark);
            border-right: 2px solid var(--border-dark);
            font-size: 0.95rem;
        }

        .compare-table th {
            background: var(--accent-cyan);
            font-weight: 900;
            font-size: 1.05rem;
        }

        .compare-table tr:nth-child(even) {
            background: #fafafa;
        }

        .highlight-col {
            background: #fffbe6 !important;
            font-weight: 800;
        }

        /* FAQ Accordion */
        .faq-list {
            display: flex;
            flex-direction: column;
            gap: 16px;
            max-width: 900px;
            margin: 0 auto;
        }

        .faq-item {
            background: #fff;
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            box-shadow: var(--shadow-doodle);
            overflow: hidden;
        }

        .faq-question {
            padding: 18px 24px;
            font-weight: 800;
            font-size: 1.1rem;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            background: #fff;
            user-select: none;
        }

        .faq-question:after {
            content: "+";
            font-size: 1.5rem;
            font-weight: 900;
        }

        .faq-item.active .faq-question:after {
            content: "−";
        }

        .faq-answer {
            padding: 0 24px 18px;
            display: none;
            color: #3f3f46;
            font-size: 0.98rem;
            border-top: 2px dashed #e4e4e7;
            padding-top: 14px;
        }

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

        /* Reviews Section */
        .review-card {
            background: #fff;
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            padding: 20px;
            box-shadow: var(--shadow-doodle);
        }

        .review-user {
            display: flex;
            align-items: center;
            gap: 12px;
            margin-bottom: 12px;
        }

        .user-avatar {
            width: 44px;
            height: 44px;
            border-radius: 50%;
            border: 2px solid var(--border-dark);
            background: var(--accent-yellow);
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 900;
        }

        /* Contact & Form Section */
        .contact-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 30px;
        }

        .contact-info-box {
            background: var(--accent-cyan);
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            padding: 30px;
            box-shadow: var(--shadow-doodle);
        }

        .form-box {
            background: #fff;
            border: var(--border-width) solid var(--border-dark);
            border-radius: var(--radius-doodle);
            padding: 30px;
            box-shadow: var(--shadow-doodle);
        }

        .form-group {
            margin-bottom: 18px;
        }

        .form-group label {
            display: block;
            font-weight: 800;
            margin-bottom: 6px;
            font-size: 0.95rem;
        }

        .form-control {
            width: 100%;
            padding: 12px 14px;
            border: 2px solid var(--border-dark);
            border-radius: 10px;
            font-size: 0.95rem;
            outline: none;
            background: #fafafa;
        }

        .form-control:focus {
            background: #fff;
            border-color: var(--accent-purple);
            box-shadow: 2px 2px 0px var(--border-dark);
        }

        /* Articles & Links Footer */
        .footer-sec {
            background: #ffffff;
            border-top: var(--border-width) solid var(--border-dark);
            padding: 50px 0 20px;
            color: var(--main-text);
        }

        .footer-grid {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1.5fr;
            gap: 30px;
            margin-bottom: 40px;
        }

        .friend-links, .article-links {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-top: 10px;
        }

        .friend-links a, .article-links a {
            background: #f4f4f5;
            padding: 6px 12px;
            border-radius: 8px;
            border: 2px solid var(--border-dark);
            font-size: 0.85rem;
            font-weight: 700;
            box-shadow: 2px 2px 0px var(--border-dark);
        }

        .friend-links a:hover, .article-links a:hover {
            background: var(--accent-yellow);
        }

        .copyright-bar {
            text-align: center;
            padding-top: 20px;
            border-top: 2px solid var(--border-dark);
            font-size: 0.9rem;
            font-weight: 700;
            color: #52525b;
        }

        /* Float Widget */
        .float-kefu {
            position: fixed;
            right: 20px;
            bottom: 30px;
            z-index: 999;
            background: var(--accent-yellow);
            border: var(--border-width) solid var(--border-dark);
            border-radius: 50px;
            padding: 10px 18px;
            font-weight: 900;
            box-shadow: var(--shadow-doodle);
            cursor: pointer;
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .float-kefu:hover {
            transform: translate(-3px, -3px);
            box-shadow: var(--shadow-hover);
        }

        /* Responsive Design */
        @media (max-width: 992px) {
            .grid-4, .stats-grid { grid-template-columns: repeat(2, 1fr); }
            .grid-3 { grid-template-columns: repeat(2, 1fr); }
            .footer-grid { grid-template-columns: 1fr 1fr; }
            .contact-grid { grid-template-columns: 1fr; }
            .hero-title { font-size: 2.2rem; }
        }

        @media (max-width: 768px) {
            .mobile-menu-btn { display: block; }
            .nav-links {
                display: none;
                position: absolute;
                top: 100%;
                left: 0;
                width: 100%;
                background: #fff;
                flex-direction: column;
                padding: 15px 0;
                border-bottom: var(--border-width) solid var(--border-dark);
            }
            .nav-links.active { display: flex; }
            .grid-4, .grid-3, .grid-2, .stats-grid { grid-template-columns: 1fr; }
            .footer-grid { grid-template-columns: 1fr; }
            .hero-title { font-size: 1.8rem; }
        }