* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(270deg, #6a11cb, #2575fc, #6a11cb);
  background-size: 600% 600%;
  animation: gradientBG 20s ease infinite;
  color: #222;
  padding: 20px;
}

@keyframes gradientBG {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}

.container {
  background-color: rgba(255, 255, 255, 0.9);
  max-width: 350px;
  width: 100%;
  padding: 30px;
  border-radius: 16px;
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
  text-align: center;
  transition: box-shadow 0.3s ease;
  cursor: default;
}

.container:hover {
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.25);
}

h2 {
  color: #2575fc;
  font-weight: 700;
  font-size: 28px;
  margin-bottom: 25px;
  letter-spacing: 1px;
  text-transform: uppercase;
  user-select: none;
}

input[type="date"],
input[type="text"] {
  width: 100%;
  padding: 12px 15px;
  font-size: 16px;
  border: 2px solid #ccc;
  border-radius: 10px;
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
  outline: none;
  user-select: text;
}

input[type="date"]:focus,
input[type="text"]:focus {
  border-color: #2575fc;
  box-shadow: 0 0 12px rgba(37, 117, 252, 0.5);
}

button {
  margin-top: 20px;
  width: 100%;
  padding: 14px 0;
  font-size: 18px;
  font-weight: 700;
  color: white;
  background: linear-gradient(45deg, #2575fc, #6a11cb);
  border: none;
  border-radius: 12px;
  cursor: pointer;
  box-shadow: 0 6px 15px rgba(37, 117, 252, 0.6);
  transition: background 0.4s ease, box-shadow 0.4s ease, transform 0.2s ease;
  user-select: none;
}

button:hover {
  background: linear-gradient(45deg, #6a11cb, #2575fc);
  box-shadow: 0 8px 25px rgba(106, 17, 203, 0.75);
  transform: scale(1.05);
}

button:active {
  transform: scale(0.97);
}

#result {
  margin-top: 25px;
  font-weight: 600;
  font-size: 20px;
  color: #333;
  min-height: 30px;
  user-select: none;
}

.error {
  color: #e63946;
  font-weight: 700;
  margin-top: 15px;
  user-select: none;
}