style.css

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

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

body {
  background-color: #d4ffeb;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  font-family: 'DynaPuff', cursive;
}

label[for="difficulty"] {
  margin: 0 20px;
  font-size: 14px;
  font-weight: bold;
}

.setting-btn {
  position: absolute !important;
  bottom: 10px;
  left: 10px;
}

.settings {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  background-color: rgb(0, 102, 255);
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  transform: translateY(0);
  transition: transform .5s ease-in-out;
  color: #fff;
}

.settings.hide {
  transform: translateY(-100%);
}

.container {
  background-color: rgb(0, 162, 255);
  padding: 10px 10px 20px 10px;
  border-radius: 10px;
  box-shadow: 0 3px 5px rgba(0, 0, 0, .3);
  color: #fff;
  position: relative;
  text-align: center;
  width: 500px;
  z-index: -5;
}

.container h2 {
  background-color: rgba(255, 255, 255, 0.274);
  padding: 8px;
  border-radius: 10px;
  margin: 0 0 40px;
}

.container small {
  color: rgb(255, 255, 255);
}

.container h1 {
  margin-bottom: 10px;
}

.container input {
  border: none;
  border-radius: 10px;
  font-size: 14px;
  width: 300px;
  padding: 12px 20px;
  outline: none;
}

.score-container {
  position: absolute;
  top: 70px;
  right: 20px;
}

.time-container {
  position: absolute;
  top: 70px;
  left: 20px;
}

@keyframes colorChanger {
  from {
    background-color: #000;
  }

  to {
    background-color: red;
  }
}

.end-game {
  background-color: #000;
  color: #fff;
  border-radius: 10px;
  display: none;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  animation: colorChanger 1s ease-in-out infinite alternate;
}

.end-game>* {
  margin: 10px;
}