* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(to right, #74ebd5, #acb6e5);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  transition: background 0.3s;
}

body.dark {
  background: #1c1c1c;
  color: #eee;
}

/* Top Bar */
.top-bar {
  width: 100%;
  background-color: #0a0546;
  color: white;
  padding: 20px;
  text-align: center;
  font-size: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
body.dark .top-bar {
  background-color: #333;
  color: #fff;
}

/* Toggle Switch */
.toggle-switch {
  margin-right: 20px;
  position: relative;
  display: inline-block;
  width: 50px;
  height: 24px;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  transition: .4s;
  border-radius: 24px;
}

.slider:before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .4s;
  border-radius: 50%;
}

.toggle-switch input:checked + .slider {
  background-color: #4caf50;
}

.toggle-switch input:checked + .slider:before {
  transform: translateX(26px);
}

/* Container */
.container {
  width: 90%;
  max-width: 600px;
  margin-top: 40px;
  background: linear-gradient(135deg, #ffffff, #e0f7fa);
  border: 3px solid #0a0546;
  border-radius: 15px;
  padding: 30px;
  box-shadow: 0 0 15px rgba(0,0,0,0.2);
  transition: all 0.3s;
}

body.dark .container {
  background: #333;
  border-color: #888;
}

/* Question */
h3 {
  font-size: 22px;
  margin-bottom: 20px;
  color: #0a0546;
}

body.dark h3 {
  color: #fff;
}

/* Options */
.options {
  display: flex;
  flex-direction: column;
}

.option {
  background: #f0f8ff;
  color: #333;
  border: 2px solid #74b9ff;
  border-radius: 8px;
  padding: 15px;
  margin: 10px 0;
  transition: all 0.3s;
  cursor: pointer;
}

body.dark .option {
  background: #444;
  color: #eee;
  border-color: #999;
}

.option:hover {
  background-color: #74b9ff;
  color: white;
  transform: scale(1.02);
}

.option.correct {
  background-color: #00b894;
  color: white;
  border-color: #00b894;
}

.option.incorrect {
  background-color: #d63031;
  color: white;
  border-color: #d63031;
}

/* Next Button */
#nextButton {
  margin-top: 20px;
  padding: 12px 20px;
  background-color: #0a0546;
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  cursor: pointer;
  display: none;
  transition: background 0.3s ease;
}

#nextButton:hover {
  background-color: #1e3799;
}

#restartBtn {
  margin-top: 20px;
  padding: 12px 20px;
  background-color: green;
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  cursor: pointer;
  display: none;
  transition: background 0.3s ease;
}