style.css

header h1 {
  display: inline-block;
  margin: 10px 0;
}
header + hr {
  margin: 10px 0;
}
#contacts p,
#contacts p.lead {
  margin: 0;
}
.userAuth {
  display: block;
  margin: 20px 0 0;
}
.modal-header:last-child {
  border-bottom: 0;
}
.card {
  display: inline-block;
  margin: 1em;
  max-width: calc(25% - 2em);
}
#contacts {
  margin-left: -1em;
  margin-right: -1em;
  display: flex;
  flex-wrap: wrap;
}
.user-info {
  display: inline-block;
  margin: 0 0.5em;
}
.user-info img {
  display: inline-block;
  max-width: 2em;
}

.auth-true .authenticated,
.auth-false .unauthenticated {
  display: block;
}
.auth-true .unauthenticated,
.auth-false .authenticated {
  display: none;
}
#contacts .contact {
  width: 18rem;
}
.delete-button {
  font-size: 0.8rem;
  float: right;
  margin-left: 0.5rem;
  padding: 0.05rem 0.3rem;
  border: 1px solid transparent;
}
.delete-button:hover {
  box-shadow: 0 0 5px 3px rgba(100, 100, 100, 0.3x);
  border: 1px solid #aaa;
}