body {
  font-family: Arial, sans-serif;
  padding: 20px;
  max-width: 800px;
  margin: auto;
}
.hidden {
  display: none;
}
.container {
  display: flex;
}
.sidebar {
  width: 200px;
  margin-right: 20px;
}
.main {
  flex: 1;
}
input, button {
  margin-top: 10px;
  padding: 8px;
  width: 100%;
  box-sizing: border-box;
}
.input-colors {
  width: 100px;
  height: 40px;
}
button {
  background-color: slateblue;
  color: white;
  font-size: large;
  border: none;
  border-radius: 5px;
  padding: 10px;
}
label {
  margin-top: 15px;
  display: block;
  font-weight: bold;
}
#qr-image img {
  margin-top: 20px;
  border: 1px solid #ccc;
  padding: 10px;
  background: #fff;
}
.notice {
  background: #fef2f2;
  padding: 15px;
  border: 1px solid #fe5277;
  margin-bottom: 20px;
  font-size: 14px;
}