* {
    font-family: 'Open Sans', sans-serif;
}

html {
    height: 100%;
    background-color: maroon;
}

h1 {
    text-align: center;
    font-size: 2em;
    color: white;
    margin-bottom: 50px;
    display: none;
}

.holder {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding-top: 100px;
}

.calc {
    background-color: rgb(20, 20, 20);
    padding: 25px 20px;
    border: 4px solid darkred;
    border-radius: 15px;
    box-shadow: 0px 0px 10px black;
}

input {
    border: 2px solid darkred;
    padding: 5px;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    text-align: center;
    font-weight: bold;
    background-color: rgb(10, 10, 10);
    font-size: 1.05em;
    color: rgb(184, 0, 0);
    cursor: pointer;
    transition: 0.3s;
}

input:hover{
    background-color: rgb(184, 0, 0);
    color: rgb(10, 10, 10);
}

.disp {
    border: 2px solid darkred;
    padding: 5px 10px;
    margin: 3px;
    width: 155px;
    text-align: right;
    font-size: 1.5em;
    border-radius: 10px;
    cursor: default;
}

.disp:hover{
    background-color: rgb(10, 10, 10);
    color: rgb(184, 0, 0);
}

.disp::placeholder {
    color: rgba(184, 0, 0, 0.6);
}

.ac {
    padding: 5px;
    margin: 3px;
    text-align: center;
}