body {
    margin: 0;
    padding: 0;
    font-family: 'sans-serif';
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #e0e0e0; /* Light background color */
}

#calc-background {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin-top: 100px;
    border-radius: 25px;
    height: 298px;
    width: 210px;
    background-color: whitesmoke; /* Purple background color */
    box-shadow: inset 0 0 15px rgba(0, 0, 0, 0.2), 0 0 15px rgba(255, 255, 255, 0.2);
}

#screen {
    width: 176px;
    height: 25px;
    padding: 5px;
    margin-bottom: 5px;
    background-color: lightgreen;
    border-radius: 10px;
    display: flex;
    flex-direction: row;
    overflow: hidden;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.2), inset 0 0 10px rgba(255, 255, 255, 0.2);
    justify-content: flex-end;
    align-items: center;
    text-align: right;
    padding-right: 10px;
    gap: 4px;
}

#keypad {
    border: none;
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    height: 220px;
    width: 176px;
    gap: 5px;
    padding: 5px;
    border-radius: 20px;
    background-color: #e0e0e0;
    box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.2), inset 0 0 8px rgba(255, 255, 255, 0.2); /* Neumorphic inset shadow */
}

button {
    height: 40px;
    width: 40px;
    font-weight: bold;
    font-size: 15px;
    border-radius: 50%;
    background-color: #e0e0e0;
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.2), 0 0 8px rgba(255, 255, 255, 0.2); /* Neumorphic shadow */
    transition: box-shadow 0.2s;
    border: 1px solid #000;
}

button:active {
    box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.2), inset 0 0 8px rgba(255, 255, 255, 0.2); /* Neumorphic pressed effect */
}

.operator, .equals {
    background-color: orange;
    background: linear-gradient(to bottom, #ffa500, #ff8c00);
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.2), 0 0 8px rgba(255, 255, 255, 0.2);
}

#ac, #erase, #pos-neg {
    background-color: gray;
    background: linear-gradient(to bottom, #d3d3d3, #a9a9a9);
}

#erase {
    font-family: 'Noto Sans Symbols 2';
    font-size: 20px;
    padding-top: 5px;
    padding-right: 10px;
}

.number {
    background-color: pink;
    background: linear-gradient(to bottom, #ffb6c1, #ff69b4);
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.2), 0 0 8px rgba(255, 255, 255, 0.2); /* Neumorphic shadow */
}

#zero {
    display: flex;
    width: 86px;
    border-radius: 20px;
    align-items: center;
    text-align: left;
    padding-left: 15px;
    background-color: #e0e0e0;
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.2), 0 0 8px rgba(255, 255, 255, 0.2); /* Neumorphic shadow */
    transition: box-shadow 0.2s;
}

#zero:active {
    box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.2), inset 0 0 8px rgba(255, 255, 255, 0.2); /* Neumorphic pressed effect */
}

footer {
    display: flex;
    justify-content: center;
    align-items: center;
    align-content: center;
    margin-top: 10px;
    border-radius: 10px;
    background-color: #fff;
    color: #000;
    padding: 10px;
    gap: 10px;
    border: none;
    font-size: 1rem;
    font-weight: bold;
    box-shadow: inset 0 0 15px rgba(0, 0, 0, 0.2), 0 0 15px rgba(255, 255, 255, 0.2);
}