style.css

html {
  box-sizing: border-box;
  font-size: 20px;
  font-family: sans-serif;
}
*,
*::before,
*::after {
  box-sizing: inherit;
}
body {
  min-height: 100vh;
  background-image: url("./images/3.jpg");
  background-size: cover;
  transition: all 0.5s;
  margin: 0;
}
h1,
h2,
h3,
h4,
p {
  margin: 0;
}
.main-wrapper {
  padding-top: 1.5rem;
  display: grid;
  gap: 1.5rem;
  justify-items: center;
}
.nav {
  display: flex;
  justify-content: center;
  align-items: center;
}
.nav > * {
  margin-left: 1.5rem;
}
.nav > *:first-child {
  margin-left: 0;
}
.nav .btn {
  padding: 0.5em 1em;
  background: #eee;
  border: 2.5px solid rgb(0, 0, 0);
  box-shadow: 2px 2px 2px rgba(0, 0, 0, 0.4);
  font-family: inherit;
  font-weight: 100;
  font-size: 0.7rem;
  border-radius: 5px;
  cursor: pointer;
}
.nav .btn:hover {
  background: rgb(225, 225, 225);
}
.main {
  text-align: center;
}

.main .time {
  font-size: 3.5rem;
  text-align: center;
  text-shadow: 5px 5px 10px rgba(0, 0, 0, 0.4);
}
.main .come-back {
  font-weight: 100;
  opacity: 0;
  transition: opacity 1s;
}
footer button {
  background: none;
  border: none;
  font-size: inherit;
  cursor: pointer;
  outline: none;
}

.icon .far {
  font-size: 2.5rem;
}
.far:hover {
  color: black;
}
@media screen and (max-width: 500px) {
  body {
    background-position-x: -200px;
  }
}