:root {
            --primary: #1a5276;
            --primary-light: #2980b9;
            --secondary: #16a085;
            --accent: #e67e22;
            --accent-light: #f39c12;
            --bg-light: #f8fafc;
            --text-dark: #2c3e50;
            --text-light: #ecf0f1;
        }
        
        body {
            font-family: 'Montserrat', sans-serif;
            color: var(--text-dark);
            background-color: var(--bg-light);
        }
        
        .bg-gradient-header {
            background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
        }
        
        .bg-gradient-card {
            background: linear-gradient(135deg, #ffffff 0%, #f8fafc 100%);
        }
        
        .btn-primary {
            background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
            color: white;
            transition: all 0.3s ease;
        }
        
        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
        }
        
        .btn-accent {
            background: linear-gradient(135deg, var(--accent) 0%, var(--accent-light) 100%);
            color: white;
            transition: all 0.3s ease;
        }
        
        .btn-accent:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
        }
        
        .nav-link {
            position: relative;
            color: var(--text-light);
            transition: all 0.3s ease;
        }
        
        .nav-link::after {
            content: '';
            position: absolute;
            width: 0;
            height: 2px;
            bottom: -3px;
            left: 0;
            background-color: var(--accent);
            transition: width 0.3s ease;
        }
        
        .nav-link:hover::after {
            width: 100%;
        }
        
        .calculator-card {
            transition: all 0.3s ease;
            border-radius: 15px;
        }
        
        .calculator-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
        }
        
        .paw-icon {
            position: absolute;
            opacity: 0.05;
            z-index: 0;
        }
        
        .result-card {
            background-color: var(--primary);
            color: var(--text-light);
            position: relative;
            overflow: hidden;
            transition: all 0.3s ease;
        }
        
        .result-card:hover {
            transform: translateY(-2px);
        }
        
        .input-range {
            -webkit-appearance: none;
            appearance: none;
            width: 100%;
            height: 10px;
            border-radius: 5px;
            background: #e2e8f0;
            outline: none;
        }
        
        .input-range::-webkit-slider-thumb {
            -webkit-appearance: none;
            appearance: none;
            width: 22px;
            height: 22px;
            border-radius: 50%;
            background: var(--accent);
            cursor: pointer;
            transition: all 0.2s ease;
        }
        
        .input-range::-webkit-slider-thumb:hover {
            transform: scale(1.2);
        }
        
        .active-tab {
            background: var(--primary);
            color: white;
        }
        
        .feeding-guide-card {
            transition: all 0.3s ease;
        }
        
        .feeding-guide-card:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
        }

        @media (max-width: 768px) {
            .calculator-section {
                padding: 1rem;
            }
        }

        .custom-range::-webkit-slider-thumb {
            background-color: var(--accent);
        }
        .custom-range::-moz-range-thumb {
            background-color: var(--accent);
        }
        .custom-range::-ms-thumb {
            background-color: var(--accent);
        }

        /* Animation classes */
        .fade-in {
            animation: fadeIn 0.5s ease-in-out;
        }
        
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }