/* Reset */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Body & Theme */
body {
  background-color: #f0f2f5;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  transition: background-color 0.3s, color 0.3s;
  color: #111;
}

body.dark {
  background-color: #1e1e1e;
  color: #f5f5f5;
}

/* Container */
.container {
  background-color: #fff;
  padding: 40px;
  border-radius: 15px;
  box-shadow: 0 8px 25px rgba(0,0,0,0.2);
  width: 100%;
  max-width: 450px;
  text-align: center;
  transition: background-color 0.3s;
}

body.dark .container {
  background-color: #2a2a2a;
}

/* Inputs & Buttons */
input[type="text"] {
  width: 100%;
  padding: 12px;
  margin: 15px 0;
  border-radius: 8px;
  border: 1px solid #ccc;
  font-size: 16px;
}

body.dark input[type="text"] {
  background-color: #3a3a3a;
  color: #f5f5f5;
  border: 1px solid #555;
}

button {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background-color: #1976d2;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
  transition: background-color 0.3s;
}

button:hover {
  background-color: #125ea7;
}

button:disabled {
  background-color: #555;
  cursor: not-allowed;
}

/* Result */
#result {
  margin-top: 20px;
  font-size: 16px;
}

/* Theme toggle */
.theme-toggle {
  margin-top: 20px;
  font-size: 14px;
}