body, html {
    height: 100%;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #f8f9fa;
}

.calculator {
    width: 320px;
    border: 1px solid #ccc;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    background: #fff;
}

.calculator-screen {
    width: 100%;
    height: 80px;
    border: none;
    background-color: #222;
    color: #fff;
    text-align: right;
    padding-right: 20px;
    padding-left: 10px;
    font-size: 2.5rem;
    border-top-left-radius: 10px;
    border-top-right-radius: 10px;
}

.calculator-keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1px;
}

.btn {
    height: 60px;
    font-size: 1.5rem;
    border: 1px solid #ccc;
    background-color: #f2f2f2;
}

.operator {
    background-color: #f9a825;
    color: white;
}

.equal-sign {
    grid-column: span 2;
    background-color: #28a745;
    color: white;
}

.all-clear {
    background-color: #dc3545;
    color: white;
}

#chat-container {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
}