body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, #e3f2fd, #e8f5e9);
}

/* HEADER */
header {
  text-align: center;
  padding: 20px;
  background: linear-gradient(135deg, #43a047, #1b5e20);
  color: white;
}

/* CONTAINER */
.container {
  max-width: 900px;
  margin: 30px auto;
  padding: 10px;
}

/* CARD (Glass Effect) */
.card {
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  padding: 20px;
  margin-bottom: 20px;
  border-radius: 12px;
  box-shadow: 0px 8px 20px rgba(0,0,0,0.1);
  transition: 0.3s;
}

.card:hover {
  transform: translateY(-3px);
}

/* INPUT GROUP */
.input-group {
  margin-bottom: 15px;
}

label {
  font-weight: bold;
  display: block;
  margin-bottom: 5px;
}

/* INPUT */
input, textarea {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid #ccc;
  transition: 0.3s;
}

/* FOCUS */
input:focus, textarea:focus {
  border-color: #4CAF50;
  box-shadow: 0 0 5px #4CAF50;
  outline: none;
}

/* VALIDATION COLORS */
input.valid {
  border: 2px solid green;
}

input.invalid {
  border: 2px solid red;
}

/* ERROR TEXT */
small {
  color: red;
  font-size: 12px;
}

/* BUTTON */
.btn {
  width: 100%;
  padding: 12px;
  background: linear-gradient(135deg, #4CAF50, #2e7d32);
  color: white;
  border: none;
  border-radius: 10px;
  font-size: 16px;
  cursor: pointer;
  transition: 0.3s;
}

.btn:hover {
  transform: scale(1.02);
}

/* OUTPUT */
.output {
  background: #e3f2fd;
}