* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: sans-serif;
  font-size: 62.5%;
  color: var(--color-9);
  font-weight: 400;
  line-height: 1;
}

.app {
  max-width: 40rem;
  margin: 0 auto;
}

.hidden {
  display: none !important;
}

.btn {
  cursor: pointer;
  transition: all 0.3s;
}

.btn:hover {
  transform: scale(1.1);
}

nav {
  padding: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.2rem;
  font-weight: 600;
}

#color-theme,
.export-data,
.import-data,
.clear-data {
  background-color: var(--color-8);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 10px;
  border: none;
  width: 4rem;
  font-size: 1rem;
}
#color-theme {
  width: 6rem;
}

#color-theme:focus {
  outline: none;
}

#world-level-9 {
  width: 1rem;
  height: 1rem;
  accent-color: var(--color-8);
}