*, *:before, *:after {
    box-sizing: border-box;
}
body {
    max-width: 100vw;
    width: 100%;
    overflow-x: hidden;
    overflow-y: auto;
    margin: 0;
    padding: 0;
}
img {
    max-width: 100%;
    height: auto;
}
.gap {
    margin-right: -5px;
    margin-left: -5px;
}
.gap > * {
    padding-right: 5px;
    padding-left: 5px;
}
.page-width {
    padding-right: 20px;
    padding-left: 20px;
}
.content-width {
    max-width: 800px;
    margin-right: auto;
    margin-left: auto;
}
.text-center {
    text-align: center;
}
.text-left {
    text-align: left;
}
.text-right {
    text-align: right;
}