:root {
  --bg-dark: #3a3a3a;
  --bg-light: #f4f4f4;
  --text-dark: #ffffff;
  --text-light: #222222;
  --accent: #be1dcc;
  --form-bg-dark: rgba(0, 0, 0, 0.6);
  --form-bg-light: #ffffff;
}

/* Reset */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  transition: background-color 0.3s ease, color 0.3s ease;
}

html, body {
  height: 100%;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  background-color: var(--bg-dark);
  background-image: url('http://subtlepatterns.subtlepatterns.netdna-cdn.com/patterns/navy_blue.png');
  color: var(--text-dark);
}

body.light-mode {
  background-color: var(--bg-light);
  background-image: none;
  color: var(--text-light);
}

a {
  color: var(--accent);
  text-decoration: none;
  font-size: 12px;
}

a:hover {
  text-decoration: underline;
}

#wrapper {
  width: 100%;
  max-width: 400px;
  animation: fadeIn 1s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

h1 {
  font-size: 32px;
  margin-bottom: 20px;
  text-align: center;
  font-weight: bold;
}

form {
  background: var(--form-bg-dark);
  padding: 25px;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.4);
}

body.light-mode form {
  background: var(--form-bg-light);
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

.input-group {
  margin-bottom: 15px;
}

input[type="text"],
input[type="password"] {
  width: 100%;
  padding: 10px;
  background: #fff;
  border: none;
  border-radius: 5px;
  font-size: 14px;
}

input:focus {
  background: #666;
  color: white;
}

button {
  width: 100%;
  padding: 10px;
  background-color: #303030;
  color: white;
  border: none;
  border-radius: 5px;
  font-size: 14px;
  cursor: pointer;
}

button:hover {
  background-color: var(--accent);
}

.links {
  text-align: center;
  margin-top: 15px;
}

.links a {
  margin: 0 5px;
  color: #a4a4a4;
}

.links a:hover {
  color: var(--accent);
}