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

body {
  background: #001e4d;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Card */
.app {
  background: #fff;
  width: 90%;
  max-width: 600px;
  border-radius: 12px;
  padding: 30px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

/* Title */
.app h1 {
  font-size: 26px;
  color: #001e4d;
  font-weight: 700;
  padding-bottom: 20px;
  border-bottom: 2px solid #eee;
}

/* Quiz */
.quiz {
  padding: 20px 0;
}

.quiz h2 {
  font-size: 20px;
  color: #001e4d;
  font-weight: 600;
  margin-bottom: 10px;
}

/* Answer buttons */
.btn {
  background: #fff;
  color: #222;
  font-weight: 500;
  width: 100%;
  border: 1px solid #ddd;
  padding: 12px;
  margin: 10px 0;
  cursor: pointer;
  text-align: left;
  border-radius: 6px;
  transition: all 0.25s ease;
}

.btn:hover:not(:disabled) {
  background: #001e4d;
  color: #fff;
  border-color: #001e4d;
  transform: translateY(-1px);
}

/* Disabled state */
.btn:disabled {
  cursor: not-allowed;
  opacity: 0.7;
}

/* Next button */
#next-btn {
  background: #001e4d;
  color: #fff;
  font-weight: 600;
  width: 160px;
  border: none;
  padding: 12px;
  margin: 25px auto 0;
  border-radius: 6px;
  cursor: pointer;
  display: none;
  transition: all 0.25s ease;
}

#next-btn:hover {
  background: #003a99;
  transform: translateY(-1px);
}

/* Correct & wrong */
.correct {
  background: #9aeabc !important;
  border-color: #9aeabc !important;
  color: #033d1c;
}

.wrong {
  background: #ff9393 !important;
  border-color: #ff9393 !important;
  color: #5a0000;
}

/* Responsive */
@media (max-width: 480px) {
  .app {
    padding: 20px;
  }

  .quiz h2 {
    font-size: 18px;
  }
}