body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #f9f9f9;
  color: #333;
}

/* Hero */
.hero {
  background: linear-gradient(rgba(0,0,0,0.6), rgba(0,0,0,0.6)), 
              url("https://images.unsplash.com/photo-1510511459019-5dda7724fd87") no-repeat center center/cover;
  color: white;
  text-align: center;
  padding: 80px 20px;
}
.hero img {
  width: 80px;
  margin-bottom: 10px;
}
.hero h1 {
  font-size: 2.5rem;
  margin: 10px 0;
}
.hero p {
  font-size: 1.2rem;
}
.hero .btn {
  margin-top: 20px;
}

/* Cards */
.card {
  display: flex;
  align-items: center;
  background: white;
  margin: 20px auto;
  padding: 20px;
  border-radius: 15px;
  box-shadow: 0 4px 10px rgba(0,0,0,0.1);
  max-width: 900px;
  gap: 20px;
}
.card img {
  width: 120px;
}
.card h2 {
  margin-top: 0;
  color: #0077cc;
}

/* Botón */
.btn {
  display: inline-block;
  padding: 12px 20px;
  background: #0077cc;
  color: white;
  border-radius: 8px;
  text-decoration: none;
  transition: 0.3s;
}
.btn:hover {
  background: #005fa3;
}

/* Footer */
footer {
  background: #222;
  color: white;
  text-align: center;
  padding: 15px;
  margin-top: 30px;
}

/* Animaciones */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}
.center {
  text-align: center;
  margin: 40px 0;
}
/* =======================
   Quiz mejorado
   ======================= */
.quiz-header {
  background: #0077cc;
  color: white;
  padding: 20px;
  text-align: center;
  border-radius: 0 0 20px 20px;
}

#quiz-container {
  max-width: 700px;
  margin: 30px auto;
  padding: 20px;
  background: white;
  border-radius: 15px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

#progress-bar {
  width: 100%;
  height: 10px;
  background: #eee;
  border-radius: 5px;
  margin-bottom: 20px;
}
#progress {
  height: 100%;
  width: 0;
  background: #0077cc;
  border-radius: 5px;
  transition: width 0.3s ease;
}

.question {
  font-size: 1.3rem;
  margin-bottom: 20px;
  font-weight: bold;
  color: #222;
}

.options {
  display: grid;
  gap: 15px;
}

.option-card {
  background: #f9f9f9;
  border: 2px solid #ddd;
  padding: 15px;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s ease;
}
.option-card:hover {
  background: #eef6ff;
  border-color: #0077cc;
}
.option-card.correct {
  background: #d4f8d4;
  border-color: #28a745;
}
.option-card.incorrect {
  background: #f8d4d4;
  border-color: #dc3545;
}

.result {
  text-align: center;
  font-size: 1.3rem;
  font-weight: bold;
  margin-top: 20px;
}

#next-btn {
  margin-top: 20px;
  display: block;
  width: 100%;
}