* {
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(135deg, #74ebd5, #9face6);
}

.tip {
  background: white;
  padding: 30px;
  width: 350px;
  border-radius: 15px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
  text-align: center;
}

label {
  font-size: 16px;
  font-weight: bold;
  color: #333;
}

input {
  width: 100%;
  padding: 12px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 15px;
  outline: none;
}

input:focus {
  border-color: #6c63ff;
}

button {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background: #6c63ff;
  color: white;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
}

button:hover {
  background: #574fd6;
}

#total {
  margin-top: 10px;
  background: #f4f4f4;
  font-weight: bold;
}