:root {
  font-family: Verdana, Geneva, sans-serif;
  font-size: larger;
}

body, html {
  margin: 0;
  padding: 0;
}

* {
  box-sizing: border-box;
}

body {
  width: 100%;
  display: grid;

  grid-template-areas:
    'header'
    'main'
    'footer';
  grid-template-rows: 3em auto auto;
  grid-template-columns: auto;
}

body > header {
  grid-area: header;
}

body > footer {
  grid-area: footer;
}

main {
  grid-area: main;
}

a{
  text-decoration: none;
}

body > header, body > footer, main {
  justify-self: center;
  width: clamp(45ch, 50%, 75ch);
  padding-left: 0.5em;
  padding-right: 0.5em;
}


/* nav bar / header */
body > header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  align-content: center;
}

nav ul {
  margin: 0;
  padding: 0;
  list-style-type: none;
}

nav li {
  display: block;
  float: left;
  min-width: 2em;
  max-width: 10em;
  padding-top: 0.2em;
  padding-bottom: 0.2em;
  padding-left: 0.4em;
  padding-right: 0.4em;
  margin-left: 0.2em;
  margin-right: 0.2em;
}

nav > ul > li > ul {
  visibility: hidden;
  position: absolute;
  padding-top: 0.2em;
  padding-bottom: 0.2em;
}

nav > ul > li:hover > ul {
  visibility: visible;
}

nav > ul > li > ul > li {
  float: none;
  margin-top: 0.4em;
}

nav span {
  padding-left: 0.4em;
}


/* footer */
body > footer {
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}


/* theme swticher */
.switch {
  position: relative;
  top: 0.2em;
  display: inline-block;
  width: 2em;
  height: 1em;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.switch input:checked + .slider:before {
  -webkit-transform: translateX(0.9em);
  -ms-transform: translateX(0.9em);
  transform: translateX(0.9em);
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  -webkit-transition: 0.4s;
  transition: 0.4s;
}

.slider:before {
  position:absolute;
  content: "";
  height: 0.8em;
  width: 0.8em;
  left: 0.1em;
  bottom: 0.1em;
  -webkit-transition: 0.4s;
  transition: 0.4s;
}

.slider.round {
  border-radius: 1em;
}

.slider.round:before {
  border-radius: 1em;
}