* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', sans-serif;
        }

        body {
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            padding: 20px;
        }

        .calculator {
            background: white;
            padding: 2rem;
            border-radius: 20px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.1);
            width: 100%;
            max-width: 500px;
        }

        h1 {
            color: #2c3e50;
            margin-bottom: 1.5rem;
            text-align: center;
            font-weight: 600;
        }

        .input-group {
            margin-bottom: 1.5rem;
        }

        label {
            display: block;
            margin-bottom: 0.5rem;
            color: #4a5568;
            font-weight: 500;
        }

        input {
            width: 100%;
            padding: 0.8rem;
            border: 2px solid #e2e8f0;
            border-radius: 8px;
            font-size: 1rem;
            transition: border-color 0.3s ease;
        }

        input:focus {
            outline: none;
            border-color: #4299e1;
        }

        button {
            width: 100%;
            padding: 1rem;
            background: #4299e1;
            color: white;
            border: none;
            border-radius: 8px;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: background 0.3s ease;
            margin-top: 1rem;
        }

        button:hover {
            background: #3182ce;
        }

        .result {
            margin-top: 2rem;
            padding: 1.5rem;
            background: #ebf8ff;
            border-radius: 8px;
            display: none;
        }

        .result.active {
            display: block;
            animation: fadeIn 0.3s ease;
        }

        .result h2 {
            color: #2c3e50;
            margin-bottom: 1rem;
            font-size: 1.2rem;
        }

        .result p {
            color: #4a5568;
            line-height: 1.6;
            margin-bottom: 0.5rem;
        }

        .highlight {
            color: #4299e1;
            font-weight: 600;
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(-10px); }
            to { opacity: 1; transform: translateY(0); }
        }