style.css

* {
  box-sizing: border-box;
}

body {
  color: #000000;
  font-family: sans-serif;
  margin: 0;
  padding: 0;
}

header {
  border-bottom: 2px solid #000000;
  margin-bottom: 0;
  padding: 15px;
  text-align: center;
}

h1 {
  font-size: 30px;
}

#gameGrid {
  column-gap: 5px;
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr 1fr;
  margin: 10px auto;
  max-width: 295px;
  row-gap: 10px;
  width: 100%;
}

.letter {
  align-items: center;
  border: 3px solid #c1c1c1;
  display: flex;
  font-size: 30px;
  font-weight: bold;
  height: 45px;
  justify-content: center;
  text-transform: uppercase;
  width: 45px;
}

.correct {
  background-color: #013220;
  color: #ffffff;
}

.close {
  background-color: #8B8000;
  color: #ffffff;
}

.wrong {
  background-color: #a9a9a9;
  color: #ffffff; 
}

.invalid {
  animation: flash 2s;
}

/* flashes red border and then fades back to gray */
@keyframes flash {
  5% {
    border-color: #ff0000;
  }

  100% {
    border-color: #c0c0c0;
  }
}

.win {
  animation: flicker 10s linear;
}

@keyframes flicker {
  5% {
    color: #013220;
  }

  100% {
    color: #3b823e;
  }
}

/* Wait Symbol */

.wait-container {
  align-items: center;
  display: flex;
  justify-content: center;
}

.waiting {
  animation: spin 1.5s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.show {
  visibility: visible;
}
.hidden {
  visibility: hidden;
}