html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
}

.whole {
    width: 100vw;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #1a1f2b;
}

.calculator {
    width: 320px;
    padding: 20px;
    border: 5px solid #ffffff;
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.5);
    border-radius: 10px;
    background-color: #2e3b4e;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.display-container {
    width: 100%;
    background-color: #111;
    color: white;
    font-size: 2rem;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    padding: 15px 20px;
    border-radius: 10px;
    word-wrap: break-word; 
    word-break: break-all;
    margin-bottom: 20px;
    min-height: 80px;
    box-sizing: border-box;
}

.display {
    text-align: right;
    width: 100%;
    white-space: normal;
}

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

.button-container > div {
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #4b5e7b;
    color: white;
    font-size: 1.5rem;
    padding: 20px;
    border-radius: 10px;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.button-container > div:hover {
    background-color: #6b7b92;
}

.zero {
    grid-column: span 2;
}

.secret-button {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 10px;
    background-color: #ff4081;
    color: white;
    border-radius: 5px;
    cursor: pointer;
    margin-top: 15px;
}