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

    --display-background-color: rgb(190, 190, 190);
    --operator-btn-color: #fd7329;
    --number-btn-color: #f5f5f5;
    --misc-btn-color: #ff412c;
}

body {
    display: grid;
    place-content: center;
    height: 100vh;
}

.calculator {
    width: 320px;
    border-radius: 10px;
    display: flex;  
    flex-direction: column;
    gap: 10px;
    padding: 10px;
    border: 3px solid black;
    box-shadow: 2px 2px 6px hsl(0, 0%, 50%);
}

.calculator h1 {
    text-align: center;
}

.display {
    padding: 5px 10px;
    height: 100px;
    border-radius: 10px;
    background-color: var(--display-background-color);

    display: flex;
    flex-direction: column;
    gap: 5px;
}

.error-message {
    font-size: 1.3rem;
}

.input-output {
    height: 60%;
}

.expression {
    height: 40%;
    text-align: right;
    font-size: 1.2rem;
    font-family: monospace;
    font-weight: 500;
    color: rgb(66, 66, 66);
}

.input-output{
    width: 100%;
    height: 100%;
    border: none;
    background-color: var(--display-background-color);
    text-align: right;
    outline: none;
    font-size: 1.6rem;
    font-family: monospace;
}

.buttons {
    height: 350px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2px;  
}

.button {
    border-radius: 100%;
    font-size: 1rem;
    font-weight: 500;
}

.oprtr {
    background-color: var(--operator-btn-color);
}

.number {
    background-color: var(--number-btn-color);
}

.misc {
    background-color: var(--misc-btn-color);
}

.hide {
    display: none;
}