* {
  box-sizing: border-box;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  background: #f5f5f5;
  margin: 0;
  color: #222;
}

.wrapper {
  max-width: 720px;
  margin: auto;
  padding: 20px;
}

h1 {
  text-align: center;
  margin-bottom: 5px;
}

.subtitle {
  text-align: center;
  color: #555;
  margin-bottom: 30px;
}

.card {
  background: #ffffff;
  padding: 20px;
  border-radius: 6px;
  margin-bottom: 25px;
  box-shadow: 0 0 8px rgba(0,0,0,0.05);
}

.card h2 {
  margin-top: 0;
}

.test-area {
  border: 1px solid #000;
  padding: 15px;
  margin: 15px 0;
}

.colors {
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
}

.c {
  width: 23%;
  padding: 10px;
  color: #fff;
  font-weight: bold;
  text-align: center;
}

.black { background: #000; }
.cyan { background: #00bcd4; }
.magenta { background: #e91e63; }
.yellow { background: #fbc02d; color:#000; }

button {
  background: #1976d2;
  color: #fff;
  border: none;
  padding: 12px 20px;
  font-size: 16px;
  cursor: pointer;
  border-radius: 4px;
}

button:hover {
  background: #125ea7;
}

footer {
  text-align: center;
  font-size: 13px;
  color: #777;
  margin-top: 40px;
}

@media print {
  button, footer {
    display: none;
  }
  body {
    background: white;
  }
}