/* reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    background-color: hsla(210, 100%, 5%, 1);
}

/* calc container */
main {
    height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;

}

.calculator {
    border: 1px solid black;
    border-radius: 18px;
    overflow: hidden;
}

/* screen */
.screen {
    box-sizing: border-box;
    border-bottom: 1px solid black;
    max-width: 300px;
    height: 100px;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    background-color: rgba(255, 255, 255, 0.1);
}

output {
    box-sizing: border-box;
    font-size: 3rem;
    padding-right: 14px;
    color: white;
}

/* button pad */
.buttons {
    display: flex;
    max-width: 300px;
    flex-wrap: wrap;
    box-sizing: border-box;
    gap: 2px;
}

button {
    width: 73px;
    height: 73px;
    box-sizing: border-box;
    font-size: 1rem;
    font-weight: 600;
    background-color: #293638;
    color: white;
    border: 0;
}

.clear,
.ac {
    flex-basis: 120px;
    flex-grow: 2;
    background-color: #0dbaf2;
    color: #112b33;
}

.sign {
    background-color: #0dbaf2;
    color: #112b33;
}