html {
    font-size:62.5%;
}
body {
    background-color: #ecf1f9;
    margin-top: 10%;
    margin-bottom: 10%;
}
header {
    position: fixed;
    top: 0;
    z-index: 1000;

    width: 100%;
    height: 10%;
    font-size: 2.5rem;

    background-color: #c9f2ff;
    padding: auto 0;

    align-content: center;
}
#header_title {
    color: #000;

    text-align: center;
}