:root {
        --primary-color: #e74c3c;
        --primary-dark: #c0392b;
        --secondary-color: #3498db;
        --accent-color: #f39c12;
        --success-color: #27ae60;
        --dark-color: #2c3e50;
        --darker-color: #1a252f;
        --light-gray: #f8f9fa;
        --medium-gray: #6c757d;
        --border-color: #dee2e6;
        --white: #ffffff;
        --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
        --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
        --shadow-lg: 0 10px 20px rgba(0,0,0,0.15);
    }

    * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
    }
    
    body {
        font-family: 'Inter', sans-serif;
        line-height: 1.7;
        color: var(--dark-color);
        background: var(--light-gray);
    }
    
    .container {
        max-width: 1200px;
        margin: 0 auto;
        padding: 0 1rem;
    }

    /* Header */
    .header {
        background: var(--white);
        box-shadow: var(--shadow-md);
        position: fixed;
        top: 0;
        width: 100%;
        z-index: 1000;
        transition: all 0.3s ease;
    }
    
    .nav-container {
        display: flex;
        justify-content: space-between;
        align-items: center;
        padding: 1rem 2rem;
        max-width: 1400px;
        margin: 0 auto;
    }
    
    .logo {
        display: flex;
        align-items: center;
        font-size: 1.75rem;
        font-weight: 800;
        color: var(--primary-color);
        text-decoration: none;
        z-index: 1001;
    }

    .logo i {
        margin-right: 0.5rem;
    }

    /* Burger Menu */
    .burger {
        display: flex;
        flex-direction: column;
        cursor: pointer;
        background: none;
        border: none;
        padding: 0.5rem;
        z-index: 1001;
    }
    
    .burger span {
        width: 28px;
        height: 3px;
        background: var(--dark-color);
        margin: 4px 0;
        transition: 0.3s;
        border-radius: 2px;
    }
    
    .burger.active span:nth-child(1) {
        transform: rotate(-45deg) translate(-6px, 7px);
        background: var(--white);
    }
    
    .burger.active span:nth-child(2) {
        opacity: 0;
    }
    
    .burger.active span:nth-child(3) {
        transform: rotate(45deg) translate(-6px, -7px);
        background: var(--white);
    }

    /* Navigation Overlay */
    .nav-overlay {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: linear-gradient(135deg, var(--primary-color), var(--dark-color));
        z-index: 1000;
        opacity: 0;
        visibility: hidden;
        transition: all 0.4s ease;
        overflow-y: auto;
    }

    .nav-overlay.active {
        opacity: 1;
        visibility: visible;
    }

    .nav-content {
        text-align: center;
        padding: 6rem 2rem 4rem;
        min-height: 100vh;
        display: flex;
        flex-direction: column;
        justify-content: center;
    }

    .nav-links {
        list-style: none;
        padding: 0;
    }

    .nav-links a {
        color: var(--white);
        text-decoration: none;
        font-size: 1.5rem;
        font-weight: 600;
        display: block;
        padding: 0.75rem;
        margin: 0.5rem 0;
        transition: all 0.3s ease;
        border-radius: 10px;
    }

    .nav-links a:hover {
        color: var(--accent-color);
        background: rgba(255, 255, 255, 0.1);
    }

    /* Hero Section with Cost Focus */
    .hero {
        background: linear-gradient(135deg, rgba(231, 76, 60, 0.95), rgba(52, 152, 219, 0.95));
        color: var(--white);
        padding: 8rem 0 4rem;
        margin-top: 60px;
        text-align: center;
    }

    .hero h1 {
        font-size: 2.5rem;
        font-weight: 800;
        margin-bottom: 1rem;
        text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
    }

    .hero-price {
        font-size: 3rem;
        font-weight: 900;
        color: var(--accent-color);
        text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
        margin: 1rem 0;
    }

    .hero p {
        font-size: 1.2rem;
        opacity: 0.95;
        max-width: 600px;
        margin: 0 auto 2rem;
    }

    /* Calculator Section */
    .calculator-section {
        background: var(--white);
        padding: 4rem 0;
        margin: -2rem 0 4rem;
        border-radius: 20px;
        box-shadow: var(--shadow-lg);
    }

    .calculator-container {
        max-width: 900px;
        margin: 0 auto;
        padding: 0 2rem;
    }

    .calculator-title {
        text-align: center;
        font-size: 2rem;
        font-weight: 700;
        color: var(--dark-color);
        margin-bottom: 1rem;
    }

    .calculator-subtitle {
        text-align: center;
        color: var(--medium-gray);
        margin-bottom: 3rem;
    }

    .calculator-form {
        display: grid;
        gap: 2rem;
    }

    .form-group {
        display: flex;
        flex-direction: column;
    }

    .form-label {
        font-weight: 600;
        margin-bottom: 0.5rem;
        color: var(--dark-color);
        display: flex;
        align-items: center;
        gap: 0.5rem;
    }

    .form-label i {
        color: var(--primary-color);
    }

    .form-input, .form-select {
        padding: 1rem;
        border: 2px solid var(--border-color);
        border-radius: 10px;
        font-size: 1rem;
        transition: all 0.3s ease;
    }

    .form-input:focus, .form-select:focus {
        outline: none;
        border-color: var(--primary-color);
        box-shadow: 0 0 0 3px rgba(231, 76, 60, 0.1);
    }

    .slider-container {
        position: relative;
        margin: 1rem 0;
    }

    .slider {
        width: 100%;
        height: 8px;
        border-radius: 5px;
        background: var(--border-color);
        outline: none;
        -webkit-appearance: none;
    }

    .slider::-webkit-slider-thumb {
        -webkit-appearance: none;
        appearance: none;
        width: 24px;
        height: 24px;
        border-radius: 50%;
        background: var(--primary-color);
        cursor: pointer;
        box-shadow: 0 2px 10px rgba(231, 76, 60, 0.3);
    }

    .slider::-moz-range-thumb {
        width: 24px;
        height: 24px;
        border-radius: 50%;
        background: var(--primary-color);
        cursor: pointer;
        box-shadow: 0 2px 10px rgba(231, 76, 60, 0.3);
    }

    .slider-value {
        background: var(--primary-color);
        color: white;
        padding: 0.5rem 1rem;
        border-radius: 8px;
        position: absolute;
        top: -40px;
        transform: translateX(-50%);
        font-weight: 600;
    }

    .radio-group {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 1rem;
    }

    .radio-option {
        position: relative;
    }

    .radio-option input[type="radio"] {
        position: absolute;
        opacity: 0;
    }

    .radio-label {
        display: flex;
        flex-direction: column;
        align-items: center;
        padding: 1.5rem;
        border: 2px solid var(--border-color);
        border-radius: 12px;
        cursor: pointer;
        transition: all 0.3s ease;
        text-align: center;
    }

    .radio-option input[type="radio"]:checked + .radio-label {
        border-color: var(--primary-color);
        background: rgba(231, 76, 60, 0.05);
        box-shadow: 0 4px 15px rgba(231, 76, 60, 0.2);
    }

    .radio-label i {
        font-size: 2rem;
        color: var(--primary-color);
        margin-bottom: 0.5rem;
    }

    .radio-label .material-name {
        font-weight: 600;
        color: var(--dark-color);
    }

    .radio-label .material-price {
        font-size: 0.9rem;
        color: var(--medium-gray);
    }

    .calculate-button {
        background: var(--primary-color);
        color: white;
        padding: 1.25rem 3rem;
        border: none;
        border-radius: 50px;
        font-size: 1.1rem;
        font-weight: 700;
        cursor: pointer;
        transition: all 0.3s ease;
        margin: 2rem auto 0;
        display: block;
        box-shadow: 0 5px 20px rgba(231, 76, 60, 0.3);
    }

    .calculate-button:hover {
        background: var(--primary-dark);
        transform: translateY(-2px);
        box-shadow: 0 8px 25px rgba(231, 76, 60, 0.4);
    }

    /* Results Section */
    .results-section {
        background: linear-gradient(135deg, var(--success-color), #27ae60);
        color: white;
        padding: 3rem;
        border-radius: 20px;
        margin-top: 2rem;
        display: none;
        animation: slideIn 0.5s ease;
    }

    @keyframes slideIn {
        from {
            opacity: 0;
            transform: translateY(20px);
        }
        to {
            opacity: 1;
            transform: translateY(0);
        }
    }

    .results-section.show {
        display: block;
    }

    .results-title {
        font-size: 1.8rem;
        margin-bottom: 2rem;
        text-align: center;
    }

    .results-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 2rem;
        text-align: center;
    }

    .result-item {
        background: rgba(255, 255, 255, 0.1);
        padding: 1.5rem;
        border-radius: 15px;
        backdrop-filter: blur(10px);
    }

    .result-label {
        font-size: 0.9rem;
        opacity: 0.9;
        margin-bottom: 0.5rem;
    }

    .result-value {
        font-size: 2rem;
        font-weight: 800;
    }

    .result-note {
        font-size: 0.85rem;
        opacity: 0.8;
        margin-top: 0.5rem;
    }

    /* Price Comparison Table */
    .price-table {
        background: white;
        border-radius: 15px;
        overflow: hidden;
        box-shadow: var(--shadow-lg);
        margin: 3rem 0;
    }

    .price-table-header {
        background: var(--primary-color);
        color: white;
        padding: 1.5rem;
        text-align: center;
    }

    .price-table-header h3 {
        font-size: 1.5rem;
        margin-bottom: 0.5rem;
    }

    .price-table-body {
        padding: 2rem;
    }

    table {
        width: 100%;
        border-collapse: collapse;
    }

    th, td {
        padding: 1rem;
        text-align: left;
        border-bottom: 1px solid var(--border-color);
    }

    th {
        font-weight: 600;
        color: var(--dark-color);
        background: var(--light-gray);
    }

    td {
        color: var(--medium-gray);
    }

    .price-highlight {
        color: var(--primary-color);
        font-weight: 700;
        font-size: 1.1rem;
    }

    /* Cost Factors Grid */
    .factors-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 2rem;
        margin: 3rem 0;
    }

    .factor-card {
        background: white;
        padding: 2rem;
        border-radius: 15px;
        box-shadow: var(--shadow-md);
        text-align: center;
        transition: all 0.3s ease;
        border-top: 4px solid var(--primary-color);
    }

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

    .factor-icon {
        font-size: 3rem;
        color: var(--primary-color);
        margin-bottom: 1rem;
    }

    .factor-title {
        font-size: 1.3rem;
        font-weight: 700;
        color: var(--dark-color);
        margin-bottom: 1rem;
    }

    .factor-description {
        color: var(--medium-gray);
        line-height: 1.6;
    }

    .factor-impact {
        display: inline-block;
        margin-top: 1rem;
        padding: 0.5rem 1rem;
        background: rgba(231, 76, 60, 0.1);
        color: var(--primary-color);
        border-radius: 20px;
        font-weight: 600;
        font-size: 0.9rem;
    }

    /* CTA Section */
    .cta-section {
        background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
        color: white;
        padding: 4rem 0;
        text-align: center;
        border-radius: 20px;
        margin: 3rem 0;
    }

    .cta-title {
        font-size: 2.5rem;
        font-weight: 800;
        margin-bottom: 1rem;
    }

    .cta-subtitle {
        font-size: 1.2rem;
        opacity: 0.95;
        margin-bottom: 2rem;
        max-width: 600px;
        margin-left: auto;
        margin-right: auto;
    }

    .cta-buttons {
        display: flex;
        gap: 1rem;
        justify-content: center;
        flex-wrap: wrap;
    }

    .cta-button {
        display: inline-block;
        padding: 1.25rem 2.5rem;
        background: white;
        color: var(--primary-color);
        text-decoration: none;
        border-radius: 50px;
        font-weight: 700;
        transition: all 0.3s ease;
        box-shadow: 0 5px 20px rgba(0,0,0,0.2);
    }

    .cta-button:hover {
        transform: translateY(-3px);
        box-shadow: 0 8px 25px rgba(0,0,0,0.3);
    }

    .cta-button.secondary {
        background: transparent;
        border: 2px solid white;
        color: white;
    }

    .cta-button.secondary:hover {
        background: white;
        color: var(--primary-color);
    }

    /* Info Boxes */
    .info-box {
        background: var(--light-gray);
        border-left: 4px solid var(--primary-color);
        padding: 1.5rem;
        border-radius: 10px;
        margin: 2rem 0;
    }

    .info-box-title {
        font-weight: 700;
        color: var(--dark-color);
        margin-bottom: 0.5rem;
        display: flex;
        align-items: center;
        gap: 0.5rem;
    }

    .info-box-title i {
        color: var(--primary-color);
    }

    .info-box-content {
        color: var(--medium-gray);
        line-height: 1.6;
    }

    /* Footer */
    .footer {
        background: var(--darker-color);
        color: var(--white);
        padding: 4rem 0 2rem;
        margin-top: 4rem;
    }

    .footer-content {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
        gap: 2.5rem;
        margin-bottom: 2rem;
    }

    .footer-section h3 {
        font-size: 1.4rem;
        margin-bottom: 1.5rem;
        color: var(--primary-color);
        font-weight: 700;
    }

    .footer-section p,
    .footer-section a {
        color: #bdc3c7;
        text-decoration: none;
        line-height: 1.8;
        margin-bottom: 0.5rem;
        display: block;
        transition: all 0.3s ease;
    }

    .footer-section a:hover {
        color: var(--primary-color);
    }

    .footer-bottom {
        text-align: center;
        margin-top: 3rem;
        padding-top: 2rem;
        border-top: 1px solid #34495e;
        color: #7f8c8d;
    }

    /* Responsive Design */
    @media (max-width: 768px) {
        .hero h1 {
            font-size: 2rem;
        }
        
        .hero-price {
            font-size: 2.5rem;
        }
        
        .radio-group {
            grid-template-columns: 1fr;
        }
        
        .results-grid {
            grid-template-columns: 1fr;
        }
        
        .cta-buttons {
            flex-direction: column;
        }
        
        table {
            font-size: 0.9rem;
        }
        
        th, td {
            padding: 0.75rem 0.5rem;
        }
    }