body {
  padding: 0;
  margin: 0;
  background-color: rgb(240, 240, 244);
  font-family: sans-serif;
}

main {
  background-color: rgb(230, 230, 234);
  border-radius: 8px;
}

h1 {
  font-size: 2.5em;
  color: rgb(57, 57, 61);
  margin: 0;
  width: 100%;
}

footer {
  text-align: center;
  font-size: 12px;
  color: rgb(110, 110, 114);
  text-transform: uppercase;
}

footer a {
  color: rgb(110, 110, 114);
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

#wrapper {
  margin: 0 auto;
  max-width: 500px;
  width: 100%;
  margin: 0 auto;
  padding: 0 2em;
  box-sizing: border-box;
}

#controls {
  display: flex;
  margin: 2em 0 1em 0;
  justify-content: center;
  align-items: center;
}

#controls button {
  background-color: rgb(220, 220, 224);
  border: 0;
  border-radius: 6px;
  padding: 0.7em 1.5em;
  transition: all 0.12s ease-out;
}

#controls button:not([disabled]):hover {
  cursor: pointer;
  background-color: #04bbd9;
  color: white;
}

#stage {
  margin: 4em auto 6em auto;
}

#stage section {
  width: 100%;
  min-height: 130px;
  border-radius: 8px;
  position: relative;
  display: grid;
  grid-template-columns: [c1] 33.33% [c2] 33.33% [c3] 33.33% [c-end];
  grid-template-rows: [r1] 33.33% [r2] 33.33% [r3] 33.33% [r-end];
  filter: drop-shadow(0 0 8px rgba(0, 0, 0, 0.15));
}

#stage button {
  margin: 0;
  padding: 0;
  font-size: 3em;
  background: rgb(250, 250, 252);
  color: rgb(50, 50, 55);
  overflow: hidden;
  transition: transform 0.12s ease-out, background-color 0.12s ease-out;
  border-radius: 8px;
  border: 1px solid rgb(198, 198, 201);
  grid-column-start: c1;
  grid-row-start: r1;
  z-index: 1;
}

#stage button.fast {
  transition: transform 0.08s ease-out;
}

#stage.done button[disabled] {
  background-color: #20a076;
  color: white;
}

.c1.r1 { transform: translate(0, 0); }
.c1.r2 { transform: translate(0, 100%); }
.c1.r3 { transform: translate(0, 200%); }

.c2.r1 { transform: translate(100%, 0); }
.c2.r2 { transform: translate(100%, 100%); }
.c2.r3 { transform: translate(100%, 200%); }

.c3.r1 { transform: translate(200%, 0); }
.c3.r2 { transform: translate(200%, 100%); }
.c3.r3 { transform: translate(200%, 200%); }