@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap');

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

:root {
  font-size: 62.5%;
  
  --ft-roboto: 'Roboto', sans-serif;

  --title-color: hsl(240, 9%, 89%);
  --ft-color: hsl(240, 7%, 78%);
  --ft-color-2: hsl(0, 100%, 100%);
  --button-ft-color: hsl(194, 97%, 31%);
}

body {
  height: 100vh;
  font-family: var(--ft-roboto);
  
  background-image: url(assets/mountains-universe-1.png);
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
}

a {
  text-decoration: none;
}

ul {
  list-style: none;
}

nav {
  height: 12.2rem;
  
  display: flex;
  align-items: center;
  gap: 3.3rem;
}

nav ul {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3.2rem;
}

nav ul a {
  font-family: var(--ft-roboto);
  font-size: 2rem;
  line-height: 2.2rem;
  color: var(--ft-color);

  transition: font-weight 300ms , color 300ms;
}

nav ul .active {
  font-weight: 700;
  color: var(--ft-color-2);
}

nav,
#universe,
#exploration {
  margin-left: 7.2rem;
}

h1 {
  font-size: 4.8rem;
  color: var(--title-color);
  line-height: 125%;
}

p {
  font-family: var(--ft-roboto);
  font-size: 1.8rem;
  line-height: 160%;
  color: var(--ft-color);
}

section {
  max-width: 64.8rem;
}

#home {
  text-align: center;
  margin: 17.2rem auto 0;

  display: grid;
  gap: 2.4rem;
}

#home .button {
  background: none;

  font-family: var(--ft-roboto);
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 2.4rem;
  color: var(--ft-color-2);

  width: 19.5rem;
  height: 4.8rem;
  justify-self: center;
  
  display: flex;
  align-items: center;
  justify-content: center;
  
  border: solid 2px var(--ft-color-2);
  border-radius: 8px;

  cursor: pointer;

  transition: background 300ms , color 300ms;
}

#home .button:hover {
  background-color: var(--ft-color-2);
  color: var(--button-ft-color);
}

#universe,
#exploration {
  margin-top: 6.3rem;
}

#universe,
#exploration {
  display: grid;
  gap: 1.6rem;
}