calculator.css

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

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(to right, #ff4e50, #f9d423);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.calculator {
    background-color: #2c3e50;
    padding: 20px;
    border-radius: 20px;
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.2);
}

.display {
    background-color: #34495e;
    border-radius: 10px;
    padding: 20px;
    font-size: 2em;
    color: #ecf0f1;
    text-align: right;
    margin-bottom: 20px;
    height: 60px;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 80px);
    grid-gap: 15px;
}

.buttons button {
    background-color: #1abc9c;
    border: none;
    border-radius: 10px;
    font-size: 1.5em;
    padding: 20px;
    color: #ecf0f1;
    cursor: pointer;
    transition: 0.3s ease;
}

.buttons button:hover {
    background-color: #16a085;
}

.buttons .equal {
    background-color: #e74c3c;
    grid-column: span 2;
}

.buttons .equal:hover {
    background-color: #c0392b;
}

.buttons .clear {
    background-color: #f39c12;
}

.buttons .clear:hover {
    background-color: #e67e22;
}

.buttons .operator {
    background-color: #3498db;
}

.buttons .operator:hover {
    background-color: #2980b9;
}