* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #0e0e2a;
    color: #fff;
}

.calculator {
    width: 300px;
    background-color: #141217;
    border-radius: 10px;
    overflow: hidden;
}

.display {
    background-color: #302837;
    padding: 20px;
    text-align: right;
    font-size: 2em;
    color: #d6d6d6;
}

#expression {
    font-size: 24px;
    color: #eee;
    display: block;
    margin-bottom: 5px;
}

#result {
    font-size: 20px;
    color: #b3b3b3;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    padding: 10px;
}

.btn {
    background-color: #1f1a21;
    color: #d6d6d6;
    font-size: 1.5em;
    border: none;
    border-radius: 50%;
    padding: 15px;
    cursor: pointer;
    transition: background 0.2s;
}
.spc {
    background-color: #141217;
    color: #d6d6d6;
    font-size: 1.5em;
    border: none;
    border-radius: 50%;
    padding: 15px;
    cursor: pointer;
    transition: background 0.2s;
}
.op {
    background-color: #4e4256;
    color: #d6d6d6;
    font-size: 1.5em;
    border: none;
    border-radius: 50%;
    padding: 15px;
    cursor: pointer;
    transition: background 0.2s;
}
.btnclear {
    background-color: #673a3f;
    color: #d6d6d6;
    font-size: 1.5em;
    border: none;
    border-radius: 50%;
    padding: 15px;
    cursor: pointer;
    transition: background 0.2s;
}

.btn:hover {
    background-color: #30303c;
}

/* #0e0e2a */

.equals {
    background-color: #6b00b0;
    color: #fff;
}

.equals:hover {
    background-color: #b200ff;
}