:root {
  --mainColor: rgb(0, 183, 239);
  scroll-behavior: smooth;
  scrollbar-color: var(--mainColor) black;
}

* {
  box-sizing: border-box;
}

body {
  font-family: "Open Sans", sans-serif;
}

button {
  background-color: var(--mainColor);
  color: white;
  padding: 10px;
  border: none;
  border-radius: 20px;
  font-size: 20px;
  width: 140px;
  cursor: pointer;
  opacity: 0.7;
  transition: opacity 0.3s ease, background-color 0.3s ease;
  user-select: none;
}

button:hover {
  opacity: 1;
}

a {
  text-decoration: none;
  color: white;
}

h2 {
  font-weight: bold;
  font-size: 40px;
}

.up {
  position: fixed;
  bottom: 10px;
  right: 20px;
  width: 40px;
  height: 40px;
  background-color: var(--mainColor);
  color: white;
  cursor: pointer;
  text-align: center;
  line-height: 40px;
  border-radius: 4px;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.up.show {
  opacity: 1;
  visibility: visible;
}