body {
  font-family: 'Roboto', sans-serif;
  background-color: #f8f8f8;
  color: #333; /* Default text color */
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  flex-direction: column;
  gap: 20px;
  touch-action: manipulation;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease; /* Add transition for smooth change */
}

body.dark-mode {
  background-color: #121212; /* Dark background */
  color: #eee; /* Light text color */
}

#darkModeToggle {
  position: fixed;
  top: 20px;
  right: 20px;
  padding: 10px 15px;
  border: 1px solid #00000046; /* Add border */
  border-radius: 5px;
  background-color: #e0e0e0;
  cursor: pointer;
  z-index: 10; /* Ensure button is on top */
}

#flashcard {
  background-color: #fff;
  border-radius: 15px; /* More rounded corners */
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15); /* Softer shadow */
  padding: 40px; /* Increased padding */
  text-align: center;
  max-width: 600px;
  width: 80%;
  border: none; /* Remove border */
}

body.dark-mode #flashcard {
  background-color: #333; /* Dark mode background */
  color: #fff; /* Dark mode text color */
}

.video-container {
  display: flex;
  justify-content: center; /* Center horizontally */
  align-items: center;     /* Center vertically */
  width: 100%;            /* Take full width of parent */
  max-width: 50vw;        /* Maximum width is 50% of viewport width */
  height: auto;           /* Height adjusts proportionally */
}

.video-container iframe {
  width: 100%;           /* Fill the container width */
  height: auto;          /* Maintain aspect ratio */
  aspect-ratio: 16 / 9; /* Maintain 16:9 aspect ratio */
}

#question {
  text-align: left;
  font-size: 1.6em;
  margin-bottom: 30px;
  margin-top: 30px;
  font-weight: 600; /* Slightly bolder */
  line-height: 1.3; /* Adjust line spacing for better readability */
  padding: 20px; /* Add some padding around the question text */
  border-radius: 10px; /* Add a subtle border-radius */
  background-color: rgba(255, 255, 255, 0.1); /* Add a subtle background color */
}

#formula-sheet {
  width: 95%;
  margin: 20px auto;
  background-color: #fff;
  border-radius: 15px;
  border: none;
  overflow-x: auto;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

body.dark-mode #formula-sheet {
  background-color: #333; /* Dark mode background */
  color: #fff; /* Dark mode text color */
}

.formula-category {
  padding: 10px;
  border-bottom: 1px solid #eee; /* Subtler divider */
  margin-bottom: 20px; /* Add space below each table */
}

body.dark-mode .formula-category {
  border-bottom: 1px solid #555; /* Dark mode divider */
}

#main-title {
  padding: 15px;
  border-top: none;
  border-bottom: 1px solid #eee;
  font-size: 2em;
  background-image: url('src/footer.png');
  text-align: center;
  font-weight: 600;
}

body.dark-mode #main-title {
  border-bottom: 1px solid #555; /* Dark mode divider */
}

#formula-sheet table {
  width: 100%;
  border-collapse: collapse;
}

#formula-sheet th,
#formula-sheet td {
  padding: 12px;
  text-align: center;
  border: 1px solid #eee;
}

body.dark-mode #formula-sheet th,
body.dark-mode #formula-sheet td {
  border: 1px solid #555; /* Dark mode border */
}

#formula-sheet th {
  background-color: #f5f5f5; /* Lighter background for header */
  font-weight: 600;
}

body.dark-mode #formula-sheet th {
  background-color: #444; /* Dark mode header background */
}

#formula-sheet tbody tr:nth-child(even) {
  background-color: #fafafa;
}

body.dark-mode #formula-sheet tbody tr:nth-child(even) {
  background-color: #444; /* Dark mode even row background */
}

#formula-sheet tbody tr:nth-child(odd) {
  background-color: #fff;
}

body.dark-mode #formula-sheet tbody tr:nth-child(odd) {
  background-color: #333; /* Dark mode odd row background */
}

.formula-title {
  font-size: 1.4em;
  margin-bottom: 15px;
  text-align: center;
  font-weight: 500;
}

.formula {
  font-family: 'Source Code Pro', monospace; /* More modern monospace font */
}

.nav-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  gap: 10px;
  flex-wrap: nowrap;
  overflow-x: auto;
}

.nav-controls button {
  padding: 12px 20px;
  border: 1px solid #00000046; /* Add border */
  border-radius: 5px; /* Slightly more rounded */
  background: #e0e0e0; /* Updated button color */
  cursor: pointer;
  flex-shrink: 0;
  font-weight: 500;
  font-size: 1.1em;
  transition: background-color 0.2s ease; /* Add transition */
}


.nav-controls button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

#progress {
  font-weight: 500;
  flex-shrink: 0;
}

#score {
  color: #777;
  flex-shrink: 0;
}

#logo {
  text-align: right;
  margin: 0px 0;
  border: none; /* Remove border */
  width: 100%;
}

#logo img {
  padding-top: 0px;
  max-width: 100%;
  height: auto;
}

footer {
  background-image: url('src/footer.png');
  background-size: cover;
  background-repeat: no-repeat;
  text-align: center;
  width: 100%;
  bottom: 0;
  border: none; /* Remove border */
  padding: 10px 0; /* Add some padding */
  font-size: 0.9em;
}

body.dark-mode footer {
  background-color: #333; /* Dark mode background */
  color: #fff; /* Dark mode text color */
}

.formula-category {
  padding: 1px;
  border-bottom: 1px solid #eee;
}

table {
  width: 100%;
  border-collapse: collapse;
  border: none; /* Remove table border */
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1); /* Add subtle shadow */
}

th, td {
  padding: 10px;
  text-align: center;
  border: 1px solid #eee;
}

th {
  background-color: #f5f5f5;
  font-weight: 600;
}

tbody tr:nth-child(even) {
  background-color: #fafafa;
}

tbody tr:nth-child(odd) {
  background-color: #fff;
}

td:first-child {
  width: 30%;
}

.correct {
  font-size: 2em;
  font-weight: 600;
  color: #4CAF50; /* Updated green color */
  font-family: 'Roboto', sans-serif; /* Use the main font */
  transform: rotate(0deg);
}

.incorrect {
  font-size: 3em;
  font-weight: 600;
  color: red; /* Red text for incorrect answers */
  font-family: 'Roboto', sans-serif; /* Use the main font */
  transition: transform 0.5s ease; /* Smooth transition for rotation */
}

@media (max-width: 768px) {
  .nav-controls {
    flex-direction: column;
    gap: 5px;
  }

  .nav-controls button {
    width: 100%;
    padding: 15px; /* Increase padding for better visibility */
    font-weight: bold;
  }

  #flashcard {
    width: 85%;
    padding: 20px;
  }

  #options button {
    margin: 3px; /* Add margin to create space between buttons */
    padding: 10px 20px; /* Adjust padding for better button size */
    border: none;
    border-radius: 5px;
    background-color: #e0e0e0;
    color:#121212;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.2s ease;
    font-weight: bold; /* Add bold text */
  }
  
  #options button:hover {
    background-color: #d0d0d0; /* Darken on hover */
  }
  
  #options button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
  }
}

@media (orientation: landscape) and (max-width: 768px) {
  .nav-controls {
    flex-direction: row;
    gap: 10px;
  }

  .nav-controls button {
    width: auto;
    padding: 12px 20px;
    font-weight: bold;
  }
}