docs/assets/stylesheets/extra.css
@keyframes heartbeat {
  0%, 40%, 80%, 100% {
    transform: scale(1);
  }
  20%, 60% {
    transform: scale(1.15);
  }
}
.heartbeat {
  animation: heartbeat 1000ms infinite;
}
.opacity05 {
  opacity: 0.5;
}
.opacity06 {
  opacity: 0.6;
}
.opacity07 {
  opacity: 0.7;
}
.opacity08 {
  opacity: 0.8;
}
.opacity09 {
  opacity: 0.9;
}
.contrast90 {
  filter: contrast(90%);
}
.md-header {
  background: linear-gradient(to right, #16222A, #3A6073);
}
.md-tabs {
  background: linear-gradient(to right, #16222A, #3A6073);
}
.md-footer {
  background: linear-gradient(to right, #16222A, #3A6073);
}
a.md-button.md-button--primary {
  background-color: #3A6073;
}
[data-md-color-scheme="slate"] {
  --md-footer-bg-color: linear-gradient(to right, #16222A, #3A6073);
  --md-footer-bg-color--dark: linear-gradient(to right, #16222A, #3A6073);
  --md-primary-fg-color--dark: #233743;
  --md-primary-fg-color--light: #233743;
  --md-primary-fg-color: #233743;
}
[data-md-color-scheme="default"] {
  --md-footer-bg-color: linear-gradient(to right, #16222A, #3A6073);
  --md-footer-bg-color--dark: linear-gradient(to right, #16222A, #3A6073);
  --md-primary-fg-color--dark: #233743;
  --md-primary-fg-color--light: #233743;
  --md-primary-fg-color: #5487b8;
}