BookStack/resources/assets/sass/styles.scss

@import "reset";
@import "variables";
@import "mixins";
@import "html";
@import "text";
@import "grid";
@import "blocks";
@import "buttons";
@import "forms";

header hr {
  margin-top: 0;
}

header .menu {
  margin-bottom: 0;
  list-style: none;
  li {
    display: inline-block;
    margin-left: $-m;
  }
}

.page-title input {
  display: block;
  width: 100%;
  font-size: 1.4em;
}