phone_app/app/assets/stylesheets/3-components/_header.scss

.header {
    position: relative;
    margin-bottom: ($spacer * 3);
}

.header-title {
    font-size: $h2-font-size;
    color: $header-color;
}

.header-subtitle {
    font-size: $h5-font-size;
    color: $header-color;
}