* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    background-color: #000;
    color: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    overflow: hidden;
}

.calculator {
    background-color: #111;
    border-radius: 20px;
    padding: 20px;
    box-shadow: 0 10px 30px rgba(255, 255, 255, 0.1);
    max-width: 400px;
    width: 100%;
}

.input-section {
    margin-bottom: 25px;
}

.input-section h2 {
    text-align: center;
    margin-bottom: 20px;
    color: #fff;
    font-size: 1.5rem;
}

.input-group {
    margin-bottom: 15px;
}

.input-group label {
    display: block;
    margin-bottom: 5px;
    color: #ccc;
    font-size: 0.9rem;
}

.input-group input {
    width: 100%;
    height: 50px;
    background-color: #000;
    border: 2px solid #333;
    border-radius: 10px;
    color: #fff;
    font-size: 1.2rem;
    padding: 0 15px;
    outline: none;
}

.input-group input:focus {
    border-color: #666;
}

/* Hide number input spinners */
input[type=number]::-webkit-inner-spin-button,
input[type=number]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}
input[type=number] { -moz-appearance: textfield; }

.calculate-btn {
    width: 100%;
    height: 60px;
    background-color: #fff;
    color: #000;
    border: 2px solid #ccc;
    border-radius: 15px;
    font-size: 1.3rem;
    font-weight: bold;
    cursor: pointer;
    margin-top: 10px;
    transition: all 0.2s ease;
}

.calculate-btn:hover {
    background-color: #f0f0f0;
    transform: scale(1.02);
}

.results-section {
    background-color: #222;
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 20px;
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding: 10px;
    background-color: #333;
    border-radius: 8px;
}

.result-item:last-child {
    margin-bottom: 0;
}

.result-item label {
    font-weight: bold;
    color: #ccc;
}

.result-item span {
    font-size: 1.1rem;
    font-weight: bold;
    color: #fff;
}

.status span {
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 1rem;
}

.status .success {
    background-color: #4CAF50;
    color: #fff;
}

.status .failure {
    background-color: #f44336;
    color: #fff;
}

.buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.btn {
    height: 60px;
    border: none;
    border-radius: 15px;
    font-size: 1.3rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s ease;
    outline: none;
}

.btn:hover {
    transform: scale(1.05);
}

.btn:active {
    transform: scale(0.95);
}

.number {
    background-color: #333;
    color: #fff;
    border: 2px solid #555;
}

.number:hover {
    background-color: #444;
    border-color: #666;
}

.operator {
    background-color: #666;
    color: #fff;
    border: 2px solid #888;
}

.operator:hover {
    background-color: #777;
    border-color: #999;
}

.clear {
    background-color: #666;
    color: #fff;
    border: 2px solid #888;
}

.clear:hover {
    background-color: #777;
    border-color: #999;
}

.zero {
    grid-column: span 2;
}

/* Mobile responsiveness */
@media (max-width: 480px) {
    .calculator {
        padding: 15px;
        border-radius: 15px;
    }
    
    .input-section h2 {
        font-size: 1.3rem;
    }
    
    .input-group input {
        height: 45px;
        font-size: 1.1rem;
    }
    
    .calculate-btn {
        height: 50px;
        font-size: 1.1rem;
    }
    
    .btn {
        height: 50px;
        font-size: 1.1rem;
    }
    
    .buttons {
        gap: 10px;
    }
    
    .result-item {
        padding: 8px;
    }
    
    .result-item span {
        font-size: 1rem;
    }
}

@media (max-width: 320px) {
    .input-group input {
        height: 40px;
        font-size: 1rem;
    }
    
    .calculate-btn {
        height: 45px;
        font-size: 1rem;
    }
    
    .btn {
        height: 45px;
        font-size: 1rem;
    }
}