style.css

html,
body {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  background-color: white;
}

h1 {
  color: red;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 3px 5px rgba(0, 0, 0, 0.2);
  text-align: center;
  margin: 12px;
}

h2 {
  color: blue;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 3px 5px rgba(0, 0, 0, 0.2);
  text-align: center;
  margin: 5px;
}

h3 {
  font-weight: 700;
  color: blue;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 3px 5px rgba(0, 0, 0, 0.2);
  text-align: center;
}

h4 {
  margin: 8px;
  font-weight: 600;
  text-align: center;
  color: #cc0000;
  text-shadow: 0.5px 0.5px 0.5px black;
}
/*Greetings animation*/
#initial-greeting {
  font-family: "Pacifico", "Lato", "Times New Roman";
  text-shadow: 1px 1px 1px blue;
  animation: greeting 7.7s linear infinite;
}

@keyframes greeting {
  0% {
    color: magenta;
  }
  32.8% {
    color: magenta;
  }
  33% {
    color: springgreen;
  }
  65.8% {
    color: springgreen;
  }
  66% {
    color: cyan;
  }
  99.8% {
    color: cyan;
  }
  100% {
    color: magenta;
  }
}

header {
  margin-bottom: 100px;
}

a {
  color: blue;
  font-size: 57px;
  font-weight: 800;
  text-decoration: none;
}

.level-1 {
  display: flex;
  justify-content: space-around;
  margin-bottom: 35px;
}

@media (max-width: 768px) {
  .level-1 {
    display: flex;
    flex-wrap: wrap;
  }
}

#button1 {
  background-color: green;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button1:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button2 {
  background-color: green;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button2:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button3 {
  background-color: green;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button3:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

.level-2 {
  display: flex;
  justify-content: space-around;
  margin-bottom: 35px;
}

@media (max-width: 768px) {
  .level-2 {
    display: flex;
    flex-wrap: wrap;
  }
}

#button4 {
  background-color: blue;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button4:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button5 {
  background-color: blue;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button5:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button6 {
  background-color: blue;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button6:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

.level-3 {
  display: flex;
  justify-content: space-around;
  margin-bottom: 35px;
}

@media (max-width: 768px) {
  .level-3 {
    display: flex;
    flex-wrap: wrap;
  }
}

#button7 {
  background-color: red;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button7:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button8 {
  background-color: red;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button8:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button9 {
  background-color: red;
  color: white;
  text-shadow: 3.5px 3.5px 1.5px black;
  width: 325px;
  height: 325px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button9:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

.level-4 {
  display: flex;
  justify-content: space-around;
  margin-bottom: 35px;
}

@media (max-width: 768px) {
  .level-4 {
    display: flex;
    flex-wrap: wrap;
  }
}

#button10 {
  background-color: yellow;
  color: white;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button10:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button11 {
  background-color: cyan;
  color: white;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border-radius: 17px;
  border: 3.5px solid black;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button11:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button12 {
  background-color: pink;
  color: white;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border-radius: 17px;
  border: 3.5px solid black;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button12:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

.level-5 {
  display: flex;
  justify-content: space-around;
  margin-bottom: 35px;
}

@media (max-width: 768px) {
  .level-5 {
    display: flex;
    flex-wrap: wrap;
  }
}

#button13 {
  background-color: lightgray;
  color: white;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border-radius: 17px;
  border: 3.5px solid black;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button13:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button14 {
  background-color: orange;
  color: white;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border: 3.5px solid black;
  border-radius: 17px;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button14:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button15 {
  background-color: springgreen;
  color: white;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-shadow: 1.7px 1.7px 1.7px black;
  border: 3.5px solid black;
  border-radius: 17px;
  text-align: center;
  text-decoration: none;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button15:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

.level-6 {
  display: flex;
  justify-content: space-around;
  margin-bottom: 35px;
}

@media (max-width: 768px) {
  .level-6 {
    display: flex;
    flex-wrap: wrap;
  }
}


#button16 {
  background-color: magenta;
  color: blue;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border-radius: 17px;
  border: 3.5px solid black;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button16:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button17 {
  background-color: lightblue;
  color: blue;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border-radius: 17px;
  border: 3.5px solid black;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button17:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}

#button18 {
  background-color: white;
  color: blue;
  text-shadow: 1.7px 1.7px 1.7px black;
  width: 325px;
  height: 215px;
  font-size: 53px;
  font-weight: 700;
  text-align: center;
  border-radius: 17px;
  border: 3.5px solid black;
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1),
    inset 0 0.25em 0.3em rgba(255, 255, 255, 0.35),
    inset 0 -0.25em 0.3em rgba(0, 0, 0, 0.5);
  cursor: pointer;
  margin: 17px auto;
}

#button18:hover {
  box-shadow: 0 0 0.5em rgba(0, 0, 0, 1), inset 0 0.1em 0.3em rgba(0, 0, 0, 0.5),
    inset 0 -0.1em 0.3em rgba(0, 0, 0, 0.5);
}