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

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #071a3a;
    font-family: Arial, sans-serif;
}

.calculator {
    width: 320px;
    padding: 20px;
    background: #ffffff;
    border-radius: 20px;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.3);
}

#display {
    width: 100%;
    height: 80px;
    margin-bottom: 15px;
    padding: 20px;
    background: #eef3f8;
    border-radius: 12px;

    display: flex;
    align-items: center;
    justify-content: flex-end;

    font-size: 32px;
    font-weight: bold;
    color: #071a3a;

    overflow: hidden;
}

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

button {
    height: 60px;
    border: none;
    border-radius: 12px;

    background: #e9eef5;
    color: #071a3a;

    font-size: 20px;
    font-weight: bold;

    cursor: pointer;
}

button:hover {
    background: #d8e1ed;
}

.operator {
    background: #d7e6f5;
    
}

.operator:hover{
    background: #e4eff9;
}

.clear {
    background: #f1d8d8;
    grid-column: span 3;
}

.equal {
    background: #173b73;
    color: white;
    grid-column: span 2;
    

}

.equal:hover{
    background: #3e6fbe;
}

.clear:hover{
    background:#f9e7e7 ;
}

button:active {
    transform: scale(0.95);
}