* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background-color: #0f172a;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.app-container {
  width: calc(100% - 32px); /* দুই পাশে ১৬ পিক্সেল করে খালি জায়গা রাখবে */
  max-width: 400px;
  margin: 0 auto;
  background: #1e293b;
  padding: 30px 20px;
  border-radius: 16px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.3);
  color: #fff;
  text-align: center;
}
h2 {
  margin-bottom: 24px;
  color: #38bdf8;
}

input {
  width: 100%;
  padding: 12px;
  margin-bottom: 15px;
  border: 1px solid #334155;
  border-radius: 8px;
  background: #0f172a;
  color: #fff;
}

button {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background: #0284c7;
  color: #fff;
  font-weight: bold;
  cursor: pointer;
}

button:hover {
  background: #0369a1;
}