common.css

:root {
  color-scheme: dark light; /* stylelint-disable-line property-no-unknown */
  --heading-color: red;
  --duration: 0.5s;
  --timing: ease;
}

*,
::before,
::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  transition: color var(--duration) var(--timing),
    background-color var(--duration) var(--timing);
  font-family: sans-serif;
  font-size: 12pt;
  background-color: var(--background-color);
  color: var(--text-color);
  display: flex;
  justify-content: center;
}

main {
  margin: 1rem;
  max-width: 30rem;
  position: relative;
}

h1 {
  color: var(--heading-color);
  text-shadow: 0.1rem 0.1rem 0.1rem var(--shadow-color);
  transition: text-shadow var(--duration) var(--timing);
}

img {
  max-width: 100%;
  height: auto;
  transition: filter var(--duration) var(--timing);
}

p {
  line-height: 1.5;
  word-wrap: break-word;
  overflow-wrap: break-word;
  hyphens: auto;
}

fieldset {
  border: solid 0.1rem;
  box-shadow: 0.1rem 0.1rem 0.1rem var(--shadow-color);
  transition: box-shadow var(--duration) var(--timing);
}

div {
  padding: 0.5rem;
}

aside {
  position: absolute;
  right: 0;
  padding: 0.5rem;
}

aside:nth-of-type(1) {
  top: 0;
}

aside:nth-of-type(2) {
  top: 3rem;
}

aside:nth-of-type(3) {
  top: 7rem;
}

aside:nth-of-type(4) {
  top: 12rem;
}

#content select,
#content button,
#content input[type="text"],
#content input[type="search"] {
  width: 15rem;
}

dark-mode-toggle {
  --dark-mode-toggle-remember-font: 0.75rem "Helvetica";
  --dark-mode-toggle-legend-font: bold 0.85rem "Helvetica";
  --dark-mode-toggle-label-font: 0.85rem "Helvetica";
  --dark-mode-toggle-color: var(--text-color);
  --dark-mode-toggle-background-color: none;

  margin-bottom: 1.5rem;
}

#dark-mode-toggle {
  --dark-mode-toggle-dark-icon: url("moon.png");
  --dark-mode-toggle-light-icon: url("sun.png");
  --dark-mode-toggle-icon-size: 1rem;
  --dark-mode-toggle-icon-filter: invert(100%);
}