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

body {
    background: #78b959;
}

.calculator {
    width: 100%;
    min-height: 90vh;
    background: #fff;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    max-width: 400px;
    margin: 30px auto;
    padding: 20px;
    gap: 8px;
    border-radius: 8px;
}

.calculator .output {
    background-color: rgb(70, 201, 74);
    grid-column: 1 / 5;
    color: #fff;
    display: flex;
    justify-content:flex-end;
    align-items: center;
    font-size: 40px;
    padding: 0px;
    border-radius:4px;
    word-break: break-all;
    word-wrap: break-word;
    min-width: 90%;
    min-height: 100px;
}

.calculator button {
    font-size: 20px;
    font-weight: 600;
    border: none;
    background: none;
    box-shadow: 0px 0px 8px #999999;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.calculator button:hover {
    background: #d4d4d4;
}

.span-two {
    grid-column: span 2;
}

.calculator button:last-child {
    background: rgb(70, 201, 74);
    color:#fff;
}