* {
    padding: 0;
    margin: 0;
    color: var(--text-color);
    box-sizing: border-box;
}
html {
    background-color: var(--bg-color);
    scroll-padding-top: calc(1em + var(--header-height));
}
body {
    font-size: 15px;
    font-family: var(--font-family);
    padding-top: var(--top-header-height);
    background-color: var(--background-color);
}

a {
    font-weight: 500;
    text-decoration: none;
}

main.not-found {
    line-height: 2;
    margin-top: 100px;
    text-align: center;
}

main.not-found a {
    margin-left: 3px;
    color: var(--main-color);
}

/* common classes */
.flex {
    display: -webkit-box;
    display: -moz-box;
    display: -webkit-flex;
    display: -moz-flex;
    display: -ms-flexbox;
    display: flex;
}
.flex.wrap {
    -webkit-box-lines: multiple;
    -webkit-flex-wrap: wrap;
    -moz-flex-wrap: wrap;
    -ms-flex-wrap: wrap;
    -o-flex-wrap: wrap;
    flex-wrap: wrap;
}
.flex.align-center {
    -webkit-box-align: center;
    -ms-flex-align: center;
    -webkit-align-items: center;
    align-items: center;
}
.flex.justify-between {
    -webkit-box-pack: justify;
    -ms-flex-pack: justify;
    -webkit-justify-content: space-between;
    justify-content: space-between;
}
.flex.justify-center {
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    -webkit-justify-content: center;
    justify-content: center;
}
.flex.justify-end {
    -webkit-box-pack: end;
    -ms-flex-pack: end;
    -webkit-justify-content: flex-end;
    justify-content: flex-end;
}