* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: linear-gradient(180deg, #0f172a, #1e293b);
  color: white;
}

.app {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.card {
  width: 100%;
  max-width: 420px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 24px;
  padding: 24px;
  text-align: center;
  box-shadow: 0 10px 30px rgba(0,0,0,0.25);
  backdrop-filter: blur(10px);
}

.logo {
  width: 110px;
  height: 110px;
  object-fit: cover;
  border-radius: 20px;
  margin-bottom: 16px;
}

h1 {
  margin: 0 0 8px;
  font-size: 30px;
}

.subtitle {
  margin: 0 0 20px;
  color: #cbd5e1;
  font-size: 15px;
}

.lesson-box {
  background: rgba(255,255,255,0.08);
  border-radius: 18px;
  padding: 18px;
  text-align: left;
  margin-bottom: 18px;
}

.lesson-box h2 {
  margin-top: 0;
  font-size: 20px;
}

.lesson-box p {
  margin: 10px 0;
  line-height: 1.5;
}

button {
  width: 100%;
  border: 0;
  border-radius: 16px;
  padding: 14px;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
}