main.css

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  height: 100vh;
  background: #dcc48e;
  display: flex;
  justify-content: center;
  align-items: center;
}
.main {
  width: 60%;
  text-align: center;
  color: #4e3822;
}

.btn-container {
  margin: 3rem 0;
  display: flex;
  justify-content: space-between;
}
.btn {
  width: 25%;
  font-size: 1.5rem;
  padding: 10px;
  border-radius: 5px;
  outline: none;
  background: #233d4d;
  border: 3px solid #233d4d;
  color: #d8d52b;
  transition: all 0.7s;
}
.btn:hover {
  cursor: pointer;
  color: #233d4d;
  background: #d8d52b;
}
.score-container {
  width: 70%;
  display: grid;
  grid-template-columns: 1fr 1fr;
  margin: 2rem auto;
}
.player-score,
.computer-score {
  font-size: 5rem;
  margin-top: 1.5rem;
  color: #a22c29;
  transition: all 0.3s;
}
.score-change {
  transform: scale(0.2);
  color: #d8d52b;
}
.result-container {
  height: 100px;
  display: flex;
  justify-content: center;
  align-items: center;
}
.result {
  font-size: 2rem;
  transition: all 0.5s;
}
.tie {
  color: #00bd9d;
}

@media screen and (max-width: 1000px) {
  .main {
    width: 90%;
  }
}
@media screen and (max-width: 700px) {
  .score-container {
    width: 100%;
  }
}