*,
*::before,
*::after {
    box-sizing: border-box;
    font-family: Arial, sans-serif, "Times New Roman";
    padding: 0;
    margin: 0;
}

body {
    background-color:#101828;
    color: #d1d5db;
    display: flex;
    flex-direction: column;
}

#main-header {
    background-color: #1e2939;
    padding: 20px;
}

.container {
    display: flex;
    flex-wrap: wrap;
    width: 310px;
    padding: 16px;
    background-color: #1e2939;
    border-radius: 20px;
    margin: 80px auto;
    gap: 15px;
}

.display {
    flex-basis: 100%;
    height: 70px;
    background-color: #2e3a4d;
    border-radius: 15px;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    padding: 8px;
    font-size: 32px;
    overflow: hidden;
}

.button {
    border: 1px solid #d1d5db;
    border-radius: 8px;
    width: 58px;
    height: 58px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
}

.empty-button {
    width: 58px;
    height: 58px;
}

.button:hover {
    cursor: pointer;
}

.button:active {
    background-color: #2f4058;
    cursor: pointer;
}

.highlight {
    background-color: #00786f;
    border: 1px solid #00786f;
    color: #d1d5db;
}

.highlight:active {
    background-color: #01998f;
}