:root {
            --primary: #2563eb;
            --primary-dark: #1d4ed8;
            --secondary: #10b981;
            --accent: #f59e0b;
            --light: #f8fafc;
            --dark: #1e293b;
            --gray: #64748b;
            --border: #e2e8f0;
            --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
            --transition: all 0.3s ease;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
            line-height: 1.7;
            color: var(--dark);
            background-color: #ffffff;
            overflow-x: hidden;
        }
        a {
            color: var(--primary);
            text-decoration: none;
            transition: var(--transition);
        }
        a:hover {
            color: var(--primary-dark);
        }
        .container {
            width: 100%;
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 20px;
        }
        .site-header {
            background-color: white;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 0;
        }
        .my-logo {
            font-size: 2.2rem;
            font-weight: 800;
            color: var(--primary);
            background: linear-gradient(90deg, var(--primary), var(--secondary));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            letter-spacing: -0.5px;
        }
        .my-logo:hover {
            opacity: 0.9;
        }
        .main-nav {
            display: flex;
            gap: 30px;
        }
        .nav-link {
            font-weight: 600;
            color: var(--dark);
            position: relative;
            padding: 5px 0;
        }
        .nav-link:hover {
            color: var(--primary);
        }
        .nav-link::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background-color: var(--primary);
            transition: width 0.3s;
        }
        .nav-link:hover::after {
            width: 100%;
        }
        .hamburger {
            display: none;
            font-size: 1.8rem;
            cursor: pointer;
            color: var(--dark);
            background: none;
            border: none;
        }
        .breadcrumb {
            padding: 15px 0;
            font-size: 0.9rem;
            color: var(--gray);
            background-color: #f1f5f9;
            border-bottom: 1px solid var(--border);
        }
        .breadcrumb a {
            color: var(--gray);
        }
        .breadcrumb a:hover {
            color: var(--primary);
        }
        .breadcrumb i {
            margin: 0 8px;
            font-size: 0.8rem;
        }
        .main-content {
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 40px;
            padding: 40px 0;
        }
        @media (max-width: 992px) {
            .main-content {
                grid-template-columns: 1fr;
            }
        }
        article {
            background-color: white;
            border-radius: 8px;
            overflow: hidden;
        }
        .article-header {
            margin-bottom: 40px;
            padding-bottom: 25px;
            border-bottom: 2px solid var(--border);
        }
        h1 {
            font-size: 2.8rem;
            color: var(--dark);
            margin-bottom: 20px;
            line-height: 1.2;
        }
        .meta-info {
            display: flex;
            flex-wrap: wrap;
            gap: 20px;
            color: var(--gray);
            font-size: 0.95rem;
        }
        .meta-info i {
            margin-right: 5px;
        }
        .lead-paragraph {
            font-size: 1.3rem;
            color: var(--dark);
            font-weight: 500;
            margin-bottom: 30px;
            padding: 15px;
            background-color: #f0f9ff;
            border-left: 4px solid var(--primary);
            border-radius: 0 4px 4px 0;
        }
        h2 {
            font-size: 2rem;
            color: var(--dark);
            margin: 50px 0 20px;
            padding-bottom: 10px;
            border-bottom: 1px solid var(--border);
        }
        h3 {
            font-size: 1.6rem;
            color: var(--dark);
            margin: 35px 0 15px;
        }
        h4 {
            font-size: 1.3rem;
            color: var(--gray);
            margin: 25px 0 10px;
        }
        p {
            margin-bottom: 1.5rem;
            text-align: justify;
        }
        .highlight {
            background-color: #fffbeb;
            padding: 20px;
            border-radius: 8px;
            border-left: 4px solid var(--accent);
            margin: 25px 0;
        }
        .featured-image {
            width: 100%;
            height: auto;
            border-radius: 10px;
            margin: 25px 0;
            box-shadow: var(--shadow);
        }
        .float-right {
            float: right;
            margin: 15px 0 15px 25px;
            max-width: 400px;
        }
        @media (max-width: 768px) {
            .float-right {
                float: none;
                margin: 20px 0;
                max-width: 100%;
            }
        }
        .solver-tool {
            background: linear-gradient(135deg, #f0f9ff, #e0f2fe);
            border: 1px solid #bae6fd;
            border-radius: 12px;
            padding: 30px;
            margin: 40px 0;
            text-align: center;
        }
        .solver-tool h3 {
            color: var(--primary-dark);
            margin-top: 0;
        }
        .tool-input {
            width: 100%;
            padding: 15px;
            border: 2px solid #cbd5e1;
            border-radius: 8px;
            font-size: 1.1rem;
            margin-bottom: 15px;
            transition: border 0.3s;
        }
        .tool-input:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
        }
        .btn {
            display: inline-block;
            background-color: var(--primary);
            color: white;
            padding: 14px 28px;
            border-radius: 8px;
            font-weight: 600;
            border: none;
            cursor: pointer;
            transition: var(--transition);
            font-size: 1rem;
        }
        .btn:hover {
            background-color: var(--primary-dark);
            transform: translateY(-2px);
            box-shadow: 0 6px 12px rgba(37, 99, 235, 0.2);
        }
        .btn-secondary {
            background-color: var(--secondary);
        }
        .btn-secondary:hover {
            background-color: #0da271;
        }
        .sidebar {
            background-color: #f8fafc;
            border-radius: 10px;
            padding: 25px;
            align-self: start;
            position: sticky;
            top: 100px;
        }
        .sidebar-widget {
            margin-bottom: 30px;
        }
        .sidebar-title {
            font-size: 1.3rem;
            color: var(--dark);
            margin-bottom: 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--primary);
        }
        .search-form {
            display: flex;
        }
        .search-input {
            flex-grow: 1;
            padding: 12px;
            border: 1px solid var(--border);
            border-radius: 6px 0 0 6px;
            border-right: none;
        }
        .search-btn {
            background-color: var(--primary);
            color: white;
            border: none;
            padding: 0 20px;
            border-radius: 0 6px 6px 0;
            cursor: pointer;
        }
        .rating-widget {
            text-align: center;
        }
        .stars {
            font-size: 1.8rem;
            color: #fbbf24;
            margin: 10px 0;
            cursor: pointer;
        }
        .stars i:hover {
            color: #f59e0b;
        }
        .comments-section {
            margin-top: 50px;
            padding-top: 30px;
            border-top: 2px solid var(--border);
        }
        .comment-form {
            background-color: #f8fafc;
            padding: 25px;
            border-radius: 10px;
            margin-bottom: 40px;
        }
        .form-group {
            margin-bottom: 20px;
        }
        .form-label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
        }
        .form-input, .form-textarea {
            width: 100%;
            padding: 12px;
            border: 1px solid var(--border);
            border-radius: 6px;
            font-family: inherit;
        }
        .form-textarea {
            min-height: 150px;
            resize: vertical;
        }
        .comment {
            background-color: white;
            border: 1px solid var(--border);
            border-radius: 8px;
            padding: 20px;
            margin-bottom: 20px;
        }
        .comment-header {
            display: flex;
            justify-content: space-between;
            margin-bottom: 10px;
            font-size: 0.9rem;
            color: var(--gray);
        }
        .site-footer {
            background-color: var(--dark);
            color: #cbd5e1;
            padding: 50px 0 20px;
            margin-top: 60px;
        }
        .footer-container {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 40px;
        }
        .footer-logo {
            font-size: 2rem;
            font-weight: 800;
            color: white;
            margin-bottom: 20px;
        }
        .footer-links a {
            display: block;
            color: #94a3b8;
            margin-bottom: 10px;
        }
        .footer-links a:hover {
            color: white;
            padding-left: 5px;
        }
        friend-link {
            display: block;
            margin: 10px 0;
        }
        .copyright {
            text-align: center;
            padding-top: 30px;
            margin-top: 40px;
            border-top: 1px solid #334155;
            color: #94a3b8;
            font-size: 0.9rem;
        }
        @media (max-width: 768px) {
            h1 {
                font-size: 2.2rem;
            }
            h2 {
                font-size: 1.8rem;
            }
            h3 {
                font-size: 1.4rem;
            }
            .header-container {
                flex-wrap: wrap;
            }
            .hamburger {
                display: block;
            }
            .main-nav {
                display: none;
                flex-direction: column;
                width: 100%;
                background-color: white;
                position: absolute;
                top: 100%;
                left: 0;
                box-shadow: var(--shadow);
                padding: 20px;
                gap: 15px;
            }
            .main-nav.active {
                display: flex;
            }
        }