/* Section styling */
.section-chapters {
  background-color: #2b4359;
  padding: 30px 0;
}

.chapters-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
  justify-content: center; /* ✅ centers the grid tracks */
  justify-items: center; /* ✅ centers boxes within each track */
  margin: 0 auto;
  width: 90%;
  max-width: 1200px;
}

/* Individual box */
.chapters-box {
  flex: 1 1 200px; /* responsive width */
  max-width: 250px;
  min-width: 250px;
  height: 250px;
  background: #9cd5c0;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* Icon styling */
.chapters-icon {
  font-size: 2rem;
  color: #2b4359;
}

/* Button container */
.chapters-buttons {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Default button style */
.chapters-buttons a {
  background-color: #007bff;
  color: white;
  border-radius: 5px;
  padding: 5px 10px;
  text-decoration: none;
  transition: all 0.3s;
}

/* Default hover effect */
.chapters-buttons a:hover {
  background-color: #0056b3;
  color: #9cd5c0;
}

/* 🎯 Button hover overrides per box */
.chapters-box:nth-child() .chapters-buttons a:hover {
  background-color: #9cd5c0;
  color: #ffffff;
}

/* Buttons content, exercises, solutions, video */
/* Flex container */
.material-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
  gap: 20px;
  max-width: 1200px;
  margin: 0 auto;
}

/* Individual box */
.material-box-material {
  flex: 1 1 200px; /* responsive width */
  max-width: 160px;
  min-width: 160px;
  height: 130px;
  background: #9cd5c0;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.material-box-exercises {
  flex: 1 1 200px; /* responsive width */
  max-width: 160px;
  min-width: 160px;
  height: 130px;
  background: #027b63;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.material-box-solutions {
  flex: 1 1 200px; /* responsive width */
  max-width: 160px;
  min-width: 160px;
  height: 130px;
  background: #4a736f;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.material-box-video {
  flex: 1 1 200px; /* responsive width */
  max-width: 160px;
  min-width: 160px;
  height: 130px;
  background: #17a2b8;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.material-box-presentation {
  flex: 1 1 200px; /* responsive width */
  max-width: 160px;
  min-width: 160px;
  height: 130px;
  background: #0388a6;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* Icon styling */
.material-icon-material {
  font-size: 2rem;
  color: #2b4359;
}

/* Button container */
.material-buttons {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Default button style */
.material-buttons a {
  background-color: #007bff;
  color: white;
  border-radius: 5px;
  padding: 5px 10px;
  text-decoration: none;
  transition: all 0.3s;
}

/* Hover effect */
.material-buttons-material a:hover {
  background-color: #0056b3;
  color: #9cd5c0;
}

.material-buttons-exercises a:hover {
  background-color: #0056b3;
  color: #027b63;
}

.material-buttons-solutions a:hover {
  background-color: #0056b3;
  color: #4a736f;
}

.material-buttons-video a:hover {
  background-color: #0056b3;
  color: #17a2b8;
}

.material-buttons-presentation a:hover {
  background-color: #0056b3;
  color: #0388a6;
}

/* Responsive layout */
@media (max-width: 768px) {
  .chapters-container {
    grid-template-columns: 1fr; /* single column layout on mobile */
  }
  .material-container {
    flex-direction: column;
    align-items: center;
  }
}