/* Reset & Temel */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: 'Segoe UI', sans-serif;
  background: #0f172a;
  color: #e2e8f0;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
  position: relative;
}

/* Login Kutusu */
form {
  background: rgba(255,255,255,0.05);
  backdrop-filter: blur(12px);
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 0 20px rgba(0,0,0,0.3);
  width: 100%;
  max-width: 320px;
  animation: fadeIn 1s ease forwards;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
h2 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 22px;
  color: #fff;
}
input, button {
  width: 100%;
  padding: 10px;
  margin: 10px 0;
  border-radius: 6px;
  border: none;
  font-size: 16px;
  background: rgba(255,255,255,0.1);
  color: white;
}
input::placeholder {
  color: #ccc;
}
button {
  background: #3b82f6;
  font-weight: bold;
  transition: background 0.3s ease;
}
button:hover {
  background: #2563eb;
}
.error {
  background: rgba(248, 113, 113, 0.2);
  color: #f87171;
  padding: 10px;
  border-radius: 6px;
  margin-bottom: 10px;
  text-align: center;
  font-weight: bold;
}
@media screen and (max-width: 768px) {
  form {
    padding: 20px;
  }
  h2 {
    font-size: 20px;
  }
  input, button {
    font-size: 15px;
  }
  .error {
    font-size: 14px;
    padding: 8px;
  }
}