@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap');

* {
    box-sizing: border-box; /*if we add border or padding, it doesn't affect the width of it. */
}

:root {
    --button-color: #1e90ff;
    --circle-color: #fff;
}
body {
    background-color: #2e4057;
    font-family: 'Roboto', sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    overflow: hidden; /*don't want scroll bar to appear.*/
    margin: 0px;
}

button {
    background-color: var(--button-color);
    color: #fff;
    border: 1px solid var(--button-color);
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 2px;
    padding: 20px 30px;
    overflow: hidden;
    margin: 10px 0px;
    position: relative;
    cursor: pointer;
}

button:focus {
    outline: none;
}

button .circle {
    position: absolute;
    background-color: var(--circle-color);
    width: 100px;
    height: 100px;
    border-radius: 50%;
    transform: translate(-50%, -50%) scale(0);
    animation: scale 0.5s ease-out;
}

@keyframes scale {
    to {
        transform: translate(-50%, -50%) scale(3);
        opacity: 0;
    }
}