@import url('https://fonts.googleapis.com/css2?family=Barlow+Condensed:wght@900&display=swap');

body {
  background-color: #F9FFEA;
  font-family: Calibri, sans-serif;
  color: #1A201D;
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}
.container {
  max-width: 600px;
  width: 100%;
  text-align: center;
}
.category-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
.category-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  aspect-ratio: 1 / 1;
  font-weight: bold;
  font-size: 20px;
  padding: 20px;
  border: none;
  cursor: pointer;
  background-color: #f0f5e1;
  transition: background-color 0.3s, transform 0.3s;
}
.category-btn:hover {
  transform: translate(2px, 6px);
}
.category-btn img {
  width: 64px;
  height: 64px;
  margin-bottom: 8px;
  filter: brightness(0) saturate(100%) invert(7%) sepia(6%) saturate(400%) hue-rotate(160deg) brightness(96%) contrast(85%);
  transition: filter 0.3s;
}
.category-btn.biogas:hover { background-color: #94C11C; color: #F9FFEA; }
.category-btn.pv:hover { background-color: #36A9E1; color: #F9FFEA; }
.category-btn.agrar:hover { background-color: #DEDC00; color: #F9FFEA; }
.category-btn.technik:hover { background-color: #1A201D; color: #F9FFEA; }
.category-btn.biogas:hover img,
.category-btn.pv:hover img,
.category-btn.agrar:hover img,
.category-btn.technik:hover img {
  filter: brightness(0) saturate(100%) invert(100%);
}
#answers button {
  display: block;
  width: 100%;
  margin: 8px 0;
  padding: 12px;
  text-align: center;
  background-color: #e9f2d6;
  border: none;
  cursor: pointer;
  transition: all 0.3s;
  font-weight: bold;
  font-size: 18px;
}
#answers button:hover {
  background-color: #d5e3b9;
  transform: translate(2px, 6px);
}
#answers button.correct {
  background-color: green !important;
  color: #fff;
}
#answers button.incorrect {
  background-color: red !important;
  color: #fff;
}
#question {
  font-weight: bold;
  font-size: 20px;
  margin-bottom: 12px;
}
#explanation-box {
  color: #006532;
  margin-top: 20px;
}
.hidden { display: none; }
#progress {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 6px;
  margin: 20px 0;
}
.progress-icon {
  width: 24px;
  height: 24px;
  background-color: #ccc;
  display: inline-block;
  margin: 2px;
}
.progress-icon.correct { background-color: green; }
.progress-icon.incorrect { background-color: red; }
#end-screen {
  text-align: center;
}
#end-screen p:first-child {
  font-weight: bold;
  font-size: 32px;
}
#score-number {
  font-family: 'Barlow Condensed', sans-serif;
  font-size: 142px;
  font-weight: 900;
  margin: 10px 0;
}
#result-message {
  font-weight: regular;
  font-size: 26px;
  margin-bottom: 20px;
}
#end-screen button {
  display: block;
  margin: 0 auto;
  padding: 12px;
  width: 100%;
  text-align: center;
  background-color: #e9f2d6;
  border: none;
  cursor: pointer;
  font-weight: bold;
  font-size: 18px;
  transition: all 0.3s;
}
#end-screen button:hover {
  background-color: #d5e3b9;
  transform: translate(2px, 6px);
}

.progress-icon.correct {
  background-color: green;
  box-shadow: 0 0 8px green;
}
.progress-icon.incorrect {
  background-color: red;
  box-shadow: 0 0 8px red;
}
.fade-in {
  animation: fadeIn 0.5s ease-in-out;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}