style.css

body {
  margin: 0;
}

* {
  box-sizing: border-box;
}

.c-game {
  position: relative;
  display: inline-block;
}

.c-game__health-bar {
  position: absolute;
  display: flex;
  width: 100%;
  align-items: center;
  padding: 20px;
}

.c-game__health-bar-container {
  position: relative;
  height: 30px;
  width: 100%;
  display: flex;
  justify-content: flex-start;
}

.c-game__health-bar-container:first-child {
  justify-content: flex-end;
}

.c-game__health-bar--player {
  background-color: yellow;
  height: 30px;
  width: 100%;
}

.c-game__health-bar--fill {
  position: absolute;
  top: 0;
  width: 100%;
  bottom: 0;
  background: blue;
}

.c-game__health-bar--timer {
  background-color: red;
  height: 100px;
  width: 100px;
  flex-shrink: 0;
  display: flex;
  justify-content: center;
  align-items: center;
}

.c-game__health-bar--enemy {
  background-color: yellow;
  height: 30px;
  width: 100%;
}

.c-game-result {
  position: absolute;
  color: white;
  font-size: 50px;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  display: none;
}