/* Reset and base */
* {
  box-sizing: border-box;
}

body, html {
  height: 100%;
  margin: 0;
  font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #f7f9fc;
  color: #1f2937;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* Header */
.top-header {
  width: 100%;
  background: #111827;
  color: #f9fafb;
  padding: 20px 0;
  text-align: center;
  font-weight: 700;
  font-size: 2.4rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  user-select: none;
  letter-spacing: 1.2px;
}

/* Screens container */
.screen {
  background: #fff;
  box-shadow: 0 4px 24px rgba(0,0,0,0.12);
  border-radius: 12px;
  padding: 50px 40px;
  min-height: 480px;
  max-width: 600px;
  margin: 50px auto 40px;
  text-align: center;
  color: #1f2937;
  display: none;
  transition: box-shadow 0.3s ease;
}

.screen:hover {
  box-shadow: 0 8px 40px rgba(0,0,0,0.18);
}

.active-screen {
  display: block;
}

/* Headings */
h2 {
  font-weight: 700;
  font-size: 2.2rem;
  margin-bottom: 30px;
  color: #111827;
}

/* Quiz container */
.quiz-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 380px;
  justify-content: center;
  max-width: 700px;
  width: 100%;
}

/* Question */
.question {
  font-size: 2.4rem;
  font-weight: 600;
  margin-bottom: 40px;
  line-height: 1.3;
  color: #111827;
  text-shadow: none;
}

/* Answers container */
.answers {
  display: flex;
  flex-direction: column;
  gap: 20px;
  width: 100%;
  max-width: 550px;
  margin-bottom: 35px;
}

/* Answer buttons */
button.answer-btn {
  padding: 16px 28px;
  font-size: 1.3rem;
  border: 2px solid #3b82f6;
  border-radius: 10px;
  background: #e0e7ff;
  cursor: pointer;
  font-weight: 600;
  color: #1e40af;
  transition:
    background-color 0.3s ease,
    color 0.3s ease,
    box-shadow 0.3s ease,
    transform 0.2s ease;
  box-shadow: 0 4px 8px rgba(59, 130, 246, 0.3);
  user-select: none;
}

button.answer-btn:hover:not(:disabled) {
  background-color: #3b82f6;
  color: #fff;
  box-shadow: 0 8px 20px rgba(59, 130, 246, 0.6);
  transform: translateY(-2px);
}

button.answer-btn.correct {
  background-color: #22c55e !important;
  border-color: #16a34a !important;
  color: #fff !important;
  cursor: default;
  box-shadow: 0 6px 16px #16a34aaa;
  transform: none !important;
}

button.answer-btn.wrong {
  background-color: #ef4444 !important;
  border-color: #b91c1c !important;
  color: #fff !important;
  cursor: default;
  box-shadow: 0 6px 16px #b91c1caa;
  transform: none !important;
}

button.answer-btn:disabled {
  cursor: default;
}

/* Next button */
button.next-btn {
  padding: 14px 36px;
  font-size: 1.4rem;
  border: none;
  background: #2563eb;
  color: white;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 700;
  user-select: none;
  transition: background-color 0.3s ease, transform 0.2s ease;
  box-shadow: 0 6px 15px rgba(37, 99, 235, 0.85);
}

button.next-btn:hover {
  background-color: #1e40af;
  transform: translateY(-3px);
}

/* Score section */
.score-section {
  font-size: 2rem;
  font-weight: 700;
  color: #374151;
  margin-top: 20px;
  user-select: none;
}

/* Form inputs */
input[type="text"],
input[type="email"] {
  width: 100%;
  max-width: 400px;
  padding: 14px 18px;
  font-size: 1.2rem;
  border: 2px solid #d1d5db;
  border-radius: 10px;
  outline-offset: 2px;
  background: #f9fafb;
  color: #111827;
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.1);
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
  margin-bottom: 20px;
}

input[type="text"]:focus,
input[type="email"]:focus {
  border-color: #2563eb;
  box-shadow: 0 0 8px rgba(37, 99, 235, 0.6);
  background: #fff;
}

/* Primary buttons */
.primary-btn {
  padding: 16px 44px;
  font-size: 1.5rem;
  border: none;
  background: #2563eb;
  color: white;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 700;
  user-select: none;
  transition: background-color 0.35s ease, transform 0.2s ease;
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.9);
}

.primary-btn:hover {
  background-color: #1e40af;
  transform: translateY(-3px);
}