/* General page styling */
body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #1b1f2a;
    font-family: Arial, sans-serif;
}

/* Calculator container */
.calculator {
    background-color: #0f0f0f;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0px 4px 10px rgba(0, 0, 0, 0.3);
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Display input */
#display {
    width: 100%;
    height: 70px;
    text-align: right;
    font-size: 2rem;
    padding: 10px;
    margin-bottom: 15px;
    border: none;
    background-color: #333;
    color: white;
    border-radius: 8px;
    outline: none;
}

/* Buttons container */
.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    width: 100%;
}

/* Buttons styling */
.btn {
    width: 100%;
    height: 60px;
    font-size: 1.5rem;
    border: none;
    border-radius: 8px;
    background-color: #222;
    color: white;
    cursor: pointer;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Button hover effect */
.btn:hover {
    background-color: #444;
}

/* Special buttons */
.clear {
    background-color: #d9534f;
}

.clear:hover {
    background-color: #c9302c;
}

.delete {
    background-color: #5a5a5a;
}

.delete:hover {
    background-color: #777;
}

/* Operators */
.btn.operator {
    background-color: #ff9f43;
}

.btn.operator:hover {
    background-color: #e0893a;
}

/* Zero button spans two columns */
.zero {
    grid-column: span 2;
}

/* Equals button spans entire row */
.equals {
    background-color: #39a2db;
    font-size: 1.8rem;
    font-weight: bold;
}

.equals:hover {
    background-color: #2c81b8;
}