:root {
  --primary: #334155;
  /* Slate Blue (for buttons/borders) */
  --accent: #dc3545;
  /* Classic Red (for highlight/alert) */
  --background: #ffffff;
  /* White */
  --card-bg: #f8f8f8;
  /* Off-White */
  --text-color: #1f2937;
  /* Very Dark Gray */
}

/* Use system font stack for classic, plain look */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji",
    "Segoe UI Symbol";
  background-color: var(--background);
  color: var(--text-color);
  min-height: 100vh;
}

body::-webkit-scrollbar {
  display: none;
}

/* Custom Styles for aesthetic and security */
.btn-primary {
  background-color: var(--primary);
  color: white;
  transition: background-color 0.15s ease-in-out;
  border-radius: 0.25rem;
  /* Simpler, smaller radius */
}

.btn-primary:hover {
  background-color: #1e293b;
  /* Darker slate on hover */
}

.btn-primary:active {
  background-color: #1e293b;
}

.input-style {
  border: 1px solid #ccc;
  /* Lighter border */
  border-radius: 0.25rem;
  padding: 0.75rem;
  width: 100%;
  transition: border-color 0.2s;
}

.input-style:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 0.2rem rgba(51, 65, 85, 0.25);
  /* Subtle focus ring */
}

/* Anti-cheating styles: Disable text selection */
.quiz-active {
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

/* Progress Bar Styling */
#progress-bar-fill {
  transition: width 0.3s ease-in-out;
}

/* Icon color utilities (opposite/complementary colors) */
.icon-primary {
  color: var(--primary);
}
.icon-accent {
  color: var(--accent);
}
.icon-ink {
  color: #0f172a;
}
.icon-emerald {
  color: #10b981;
}
.icon-amber {
  color: #f59e0b;
}
.icon-indigo {
  color: #6366f1;
}

/* Subtle shine animation and hover effects */
.icon-shine {
  position: relative;
  overflow: visible;
}
.icon-shine::after {
  content: "";
  position: absolute;
  top: -30%;
  left: -40%;
  width: 160%;
  height: 160%;
  background: linear-gradient(
    120deg,
    rgba(255, 255, 255, 0) 0%,
    rgba(255, 255, 255, 0.25) 50%,
    rgba(255, 255, 255, 0) 100%
  );
  transform: translateX(-100%) rotate(15deg);
  opacity: 0;
  pointer-events: none;
}

@keyframes shimmer {
  0% {
    transform: translateX(-100%) rotate(15deg);
    opacity: 0;
  }
  40% {
    opacity: 1;
  }
  100% {
    transform: translateX(100%) rotate(15deg);
    opacity: 0;
  }
}

.icon-shine.hover-shine:hover::after {
  animation: shimmer 1s ease-in-out forwards;
}

/* Gentle periodic shimmer for attention when idle */
.icon-shine.idle-shine::after {
  animation: shimmer 2.5s ease-in-out infinite 1s;
  opacity: 0;
}

/* Hover lift for icons */
.icon-hover-zoom:hover {
  transform: scale(1.06);
  transition: transform 150ms ease-in-out;
}

/* Loading Spinner */
.loader {
  border-top-color: var(--accent);
  border-left-color: var(--primary);
  animation: spin 1s ease-in-out infinite;
  border-radius: 50%;
  border-style: solid;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }

  100% {
    transform: rotate(360deg);
  }
}