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

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    font-size: 22pt;
    font-family: Roboto, sans-serif;
    color: #fff;
    background-color: #2b2b2b;
}

.app {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 75px;
    padding: 75px;
    background-color: #353535;
    border-radius: 20px;
    box-shadow: 12px 12px 10px rgba(0, 0, 0, 0.12);
}

.field {
    min-width: 100%;
    height: fit-content;
    padding: 20px;
    font: inherit;
    font-size: .75em;
    color: inherit;
    text-align: right;
    background-color: #525252;
    border: none;
    border-radius: 10px;
}

.field:focus {
    outline: none;
}

.field::placeholder {
    font-size: .8em;
    text-align: center;
}

.buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.actions {
    display: flex;
    flex-direction: row;
    gap: 10px;
}

#eq {
    flex: auto;
}

.button {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 75px;
    height: 75px;
    border: none;
    border-radius: 10px;
    transition: .15s ease-out;
    cursor: pointer;
}

.button:active {
    transform: scale(.9);
}

.button:hover {
    box-shadow: 2px 2px 10px 0px rgba(0, 0, 0, 0.3);
}

.action {
    font-size: .75em;
    color: #fff;
    background-color: #242424;
}

.action:hover {
    background-color: hsl(from #000 h s 23%);
}

#erase {
    user-select: none;
}

.math {
    display: flex;
    flex-direction: row;
    gap: 15px;
}

.nums {
    display: grid;
    justify-content: center;
    grid-template-rows: repeat(4, 75px);
    grid-template-columns: repeat(3, 75px);
    gap: 10px;
}

.nums>:last-child {
    grid-column: 2 / span 2;
    width: auto;
}

.num {
    font-size: .75em;
    font-family: inherit;
    color: #fff;
    background-color: #525252;
}

.num:hover {
    background-color: hsl(from #525252 h s 40%);
}

.operands {
    display: flex;
    flex-direction: column;
    gap: 10px;

}

.operand {
    font-size: .75em;
    color: inherit;
    background-color: #867AA0;
}

.operand:hover {
    background-color: hsl(from #867AA0 h s 60%);
}

@media (max-width: 768px) {
    .app {
        width: 75%;
        padding: 10%;
    }

    .field {
        width: 100%;
        font-size: .5em;
    }

    .actions {
        gap: 5px;
    }

    .operands {
        gap: 5px;
    }

    .nums {
        grid-template-rows: repeat(4, 50px);
        grid-template-columns: repeat(3, 50px);
        gap: 5px;
    }

    .button {
        width: 50px;
        height: 50px;
    }

}