body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #1C1C1C;
    margin: 0;
}

.kompiouteraki {
    width: 320px;
    background-color: black;
    padding: 20px;
    border-radius: 30px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    box-shadow: 0px 10px 30px rgba(0,0,0,0.5);
}

#text {
    width: 100%;
    height: 80px;
    background: transparent;
    border: none;
    color: white;
    text-align: right;
    font-size: 50px;
    padding: 10px;
    box-sizing: border-box;
    outline: none;
}

.buttons-container {
    display: grid;
    grid-template-columns: repeat(4, 1fr); 
    gap: 12px;
}

button {
    height: 65px;
    width: 65px;
    border-radius: 50%;
    border: none;
    font-size: 24px;
    font-weight: bold;
    cursor: pointer;
    color: white;
    background-color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.2s;
}

button:active {
    background-color: #555;
}

#diairesi, #pollaplasiasmos, #afairesi, #prosthesi, #ison {
    background-color: #FF9500;
}

#katharismos, #antitheto, #mod {
    background-color: #A5A5A5;
    color: black;
}

#miden {
    grid-column: span 2; 
    width: 100%; 
    border-radius: 40px;
}

#istoriko {
    background-image: url("../calculator/istockphoto-967495780-612x612.jpg");
    background-size: cover;
    background-position: center;
}