base.css

:root {
  --base-background: inherit;
  --base-color: inherit;
  --base-font: 16px sans-serif;
  --base-link-color: #069;
  --base-link-color-hover: var(--base-link-color);
}

/**
 * A thin layer on top of normalize.css that provides a starting point more
 * suitable for web applications. Removes the default spacing and border for
 * appropriate elements.
 */

html {
  background: var(--base-background);
  color: var(--base-color);
  font: var(--base-font);
}

a {
  color: var(--base-link-color);
  text-decoration: none;
}

a:hover,
a:focus,
a:active {
  color: var(--base-link-color-hover);
  text-decoration: underline;
}

blockquote,
dl,
dd,
h1,
h2,
h3,
h4,
h5,
h6,
figure,
p,
pre {
  margin: 0;
}

button {
  background: transparent;
  border: 0;
  padding: 0;
}

/**
 * Work around a Firefox/IE bug where the transparent `button` background
 * results in a loss of the default `button` focus styles.
 */

button:focus {
  outline: 1px dotted;
  outline: 5px auto -webkit-focus-ring-color;
}

fieldset {
  border: 0;
  margin: 0;
  padding: 0;
}

iframe {
  border: 0;
}

ol,
ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

/**
 * Suppress the focus outline on links that cannot be accessed via keyboard.
 * This prevents an unwanted focus outline from appearing around elements that
 * might still respond to pointer events.
 */

[tabindex="-1"]:focus {
  outline: none !important;
}