/* ==================
   GLOBAL STYLES
   ================== */

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  transition: background-color var(--transition-speed) ease;
}

body.paint-mode {
  background-color: var(--paint-bg);
}

body.light-mode {
  background-color: var(--light-bg);
}

/* ==================
   HEADER
   ================== */

.header {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  margin-bottom: 1.5rem;
}

.header-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.header-icon {
  width: 40px;
  height: 40px;
  transition: all var(--transition-speed) ease;
}

body.paint-mode .header-icon {
  color: var(--paint-text-primary);
}

body.light-mode .header-icon {
  color: #facc15;
}

.header h1 {
  font-size: 2.25rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  transition: color var(--transition-speed) ease;
}

body.paint-mode .header h1 {
  color: var(--paint-text-primary);
}

body.light-mode .header h1 {
  color: var(--light-text-primary);
}

.header p {
  font-size: 1.125rem;
  transition: color var(--transition-speed) ease;
}

body.paint-mode .header p {
  color: var(--paint-text-secondary);
}

body.light-mode .header p {
  color: var(--light-text-secondary);
}

/* Mode Switcher */
.mode-switcher {
  display: flex;
  padding: 0.25rem;
  border-radius: 9999px;
  margin-bottom: 2rem;
  backdrop-filter: blur(8px);
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(226, 232, 240, 0.2);
}

.mode-btn {
  padding: 0.5rem 1.5rem;
  border-radius: 9999px;
  font-weight: 700;
  font-size: 0.875rem;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast) ease;
  background: transparent;
}

body.paint-mode .mode-btn.paint-btn {
  background: #ffffff;
  color: var(--paint-text-primary);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

body.paint-mode .mode-btn.light-btn {
  color: var(--paint-text-muted);
}

body.paint-mode .mode-btn.light-btn:hover {
  color: var(--paint-text-secondary);
}

body.light-mode .mode-btn.light-btn {
  background: var(--light-card);
  color: var(--light-text-primary);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

body.light-mode .mode-btn.paint-btn {
  color: var(--paint-text-muted);
}

body.light-mode .mode-btn.paint-btn:hover {
  color: var(--light-text-primary);
}

/* Accessibility Toggle */
.accessibility-toggle {
  margin-top: 1rem;
}

.accessibility-btn {
  padding: 0.5rem 1rem;
  border: 2px solid var(--paint-border);
  border-radius: 0.5rem;
  background-color: var(--paint-card);
  color: var(--paint-text-primary);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast) ease;
}

.accessibility-btn:hover {
  background-color: var(--paint-border);
}

.accessibility-btn[aria-pressed="true"] {
  background-color: var(--paint-red);
  color: white;
  border-color: var(--paint-red);
}

body.light-mode .accessibility-btn {
  border-color: var(--light-border);
  background-color: var(--light-card);
  color: var(--light-text-primary);
}

body.light-mode .accessibility-btn:hover {
  background-color: var(--light-border);
}

body.light-mode .accessibility-btn[aria-pressed="true"] {
  background-color: var(--light-red);
  color: white;
  border-color: var(--light-red);
}

/* Main Card */
.main-card {
  width: 100%;
  max-width: 28rem;
  border-radius: 1.5rem;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  transition: all var(--transition-speed) ease;
}

body.paint-mode .main-card {
  background: var(--paint-card);
  border: 1px solid var(--paint-border);
}

body.light-mode .main-card {
  background: var(--light-card);
  border: 1px solid var(--light-border);
}

/* ==================
   RESULT BLOB
   ================== */

.result-blob {
  position: relative;
  width: 16rem;
  height: 16rem;
  border-radius: 50%;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-width: 4px;
  border-style: solid;
  transition: all var(--transition-speed) ease;
  overflow: hidden;
}

body.paint-mode .result-blob {
  border-color: #f1f5f9;
  box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.1);
}

body.light-mode .result-blob {
  border-color: var(--light-border);
  box-shadow: 0 0 50px rgba(255, 255, 255, 0.2);
}

.result-blob .shine {
  position: absolute;
  top: 2rem;
  left: 2.5rem;
  width: 4rem;
  height: 2rem;
  background: white;
  opacity: 0.3;
  border-radius: 9999px;
  filter: blur(8px);
  transition: opacity var(--transition-speed) ease;
}

body.light-mode .result-blob .shine {
  opacity: 0;
}

.result-name {
  font-size: 1.875rem;
  font-weight: 700;
  transition: color var(--transition-fast) ease;
  z-index: 1;
}

/* Copy HEX Button */
.hex-display {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-top: 0.5rem;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 600;
  font-family: "Courier New", monospace;
  cursor: pointer;
  border: none;
  transition: all var(--transition-fast) ease;
  z-index: 1;
}

body.paint-mode .hex-display {
  background: rgba(0, 0, 0, 0.1);
  color: inherit;
}

body.paint-mode .hex-display:hover {
  background: rgba(0, 0, 0, 0.2);
}

body.light-mode .hex-display {
  background: rgba(255, 255, 255, 0.15);
  color: inherit;
}

body.light-mode .hex-display:hover {
  background: rgba(255, 255, 255, 0.25);
}

.hex-display:active {
  transform: scale(0.95);
}

.hex-display .copy-icon {
  width: 14px;
  height: 14px;
  opacity: 0.7;
}

.hex-display.copied {
  background: rgba(46, 204, 64, 0.3) !important;
}

/* Share Link Button */
.share-btn {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-top: 0.5rem;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition-fast) ease;
  z-index: 1;
}

body.paint-mode .share-btn {
  background: rgba(0, 0, 0, 0.1);
  color: inherit;
}

body.paint-mode .share-btn:hover {
  background: rgba(0, 0, 0, 0.2);
}

body.light-mode .share-btn {
  background: rgba(255, 255, 255, 0.15);
  color: inherit;
}

body.light-mode .share-btn:hover {
  background: rgba(255, 255, 255, 0.25);
}

.share-btn:active {
  transform: scale(0.95);
}

.share-btn .share-icon {
  width: 12px;
  height: 12px;
  opacity: 0.7;
}

.share-btn.copied {
  background: rgba(46, 204, 64, 0.3) !important;
}

/* Equation Display */
.equation-container {
  height: 3rem;
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.equation-text {
  font-size: 1.5rem;
  font-weight: 500;
  text-align: center;
  animation: pulse 2s infinite;
  transition: color var(--transition-speed) ease;
}

body.paint-mode .equation-text {
  color: var(--paint-text-primary);
}

body.light-mode .equation-text {
  color: var(--light-text-primary);
}

.examples {
  font-size: 1rem;
  font-weight: 400;
  text-align: center;
  margin-bottom: 2rem;
  color: var(--paint-text-secondary);
  transition: color var(--transition-speed) ease;
}

body.light-mode .examples {
  color: var(--light-text-secondary);
}

@keyframes pulse {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.7;
  }
}

/* Color Buttons Container */
.color-buttons {
  display: flex;
  gap: 1rem;
  width: 100%;
  justify-content: center;
  margin-bottom: 1.5rem;
}

/* Color Button */
.color-btn {
  width: 6rem;
  height: 6rem;
  border-radius: 1rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast) ease;
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.2);
  opacity: 0.8;
  transform: scale(1);
}

.color-btn:hover {
  opacity: 1;
  transform: scale(1.05);
}

.color-btn.active {
  opacity: 1;
  transform: scale(1.1);
}

/* High Contrast Mode */
body.high-contrast-mode {
  --paint-bg: #000000;
  --paint-text-primary: #ffffff;
  --paint-text-muted: #cccccc;
  --paint-border: #ffffff;
  --light-bg: #ffffff;
  --light-text-primary: #000000;
  --light-text-muted: #333333;
  --light-border: #000000;
}

body.high-contrast-mode .color-btn {
  border: 2px solid currentColor;
}

body.high-contrast-mode .result-blob {
  border: 3px solid currentColor;
}

body.high-contrast-mode .equation-text,
body.high-contrast-mode .examples {
  font-weight: 700;
}

body.paint-mode .color-btn.active {
  box-shadow: 0 0 0 4px white, 0 0 0 6px #cbd5e1;
}

body.light-mode .color-btn.active {
  box-shadow: 0 0 0 4px var(--light-bg), 0 0 0 6px white;
}

.color-btn-label {
  font-weight: 700;
  font-size: 1.125rem;
  text-transform: capitalize;
}

.active-count {
  background: rgba(0, 0, 0, 0.2);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 0.8rem;
  margin-left: 4px;
}

body.light-mode .active-count {
  background: rgba(255, 255, 255, 0.2);
}


.color-btn-label.dark-text {
  color: #1e293b;
}

.color-btn-label.light-text {
  color: white;
}

.color-btn .active-indicator {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  margin-top: 0.25rem;
  opacity: 0;
  transition: opacity var(--transition-fast) ease;
}

.color-btn.active .active-indicator {
  opacity: 1;
}

.active-indicator.dark {
  background: #1e293b;
}

.active-indicator.light {
  background: white;
}

/* Reset Button */
.reset-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: 9999px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast) ease;
  margin-top: 0.5rem;
}

.reset-btn:active {
  transform: scale(0.95);
}

body.paint-mode .reset-btn {
  background: #f1f5f9;
  color: var(--paint-text-secondary);
}

body.paint-mode .reset-btn:hover {
  background: #e2e8f0;
}

body.light-mode .reset-btn {
  background: #334155;
  color: var(--light-text-primary);
}

body.light-mode .reset-btn:hover {
  background: #475569;
}

.reset-icon {
  width: 20px;
  height: 20px;
}

/* ====================
   Sprint 6: Deep Color
   ==================== */

.deep-color-controls {
  width: 100%;
  margin: 1.5rem 0;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 1.5rem;
  background: rgba(0, 0, 0, 0.03);
  border-radius: 1rem;
  border: 1px dashed rgba(0, 0, 0, 0.1);
}

body.light-mode .deep-color-controls {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.1);
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.control-label {
  font-size: 0.875rem;
  font-weight: 700;
  display: flex;
  justify-content: space-between;
  color: inherit;
  opacity: 0.8;
}

.slider {
  -webkit-appearance: none;
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background: linear-gradient(to right, #000, var(--primary-color, #3b82f6), #fff);
  outline: none;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: white;
  border: 2px solid #3b82f6;
  cursor: pointer;
  box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.slider-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.7rem;
  font-weight: 600;
  opacity: 0.6;
}

.color-wheel-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.color-wheel {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: conic-gradient(red, yellow, lime, cyan, blue, magenta, red);
  border: 4px solid white;
  box-shadow: 0 4px 10px rgba(0,0,0,0.1);
  position: relative;
}

.harmony-text {
  font-size: 0.8rem;
  font-style: italic;
  opacity: 0.7;
}

/* Footer */
.footer {
  margin-top: 2rem;
  font-size: 0.875rem;
  transition: color var(--transition-speed) ease;
}

body.paint-mode .footer {
  color: var(--paint-text-muted);
}

body.light-mode .footer {
  color: var(--light-text-muted);
}

/* Light Mode Glow Effect */
body.light-mode .color-btn.active {
  filter: drop-shadow(0 0 20px currentColor);
}

/* ====================
   Challenge Mode Styles
   ==================== */

.challenge-bar {
  background: #10b981;
  color: white;
  width: 100%;
  max-width: 28rem;
  padding: 0.75rem;
  border-radius: 1rem;
  margin-bottom: 1.5rem;
  display: none; /* Hidden by default */
  align-items: center;
  justify-content: space-between;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  animation: slideDown 0.3s ease-out;
}

.challenge-bar.active {
  display: flex;
}

.challenge-text {
  font-weight: 600;
  font-size: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.challenge-target-dot {
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.8);
  background: white; /* Overridden by JS */
}

.challenge-btn {
  background: white;
  color: #10b981;
  border: none;
  padding: 0.25rem 0.75rem;
  border-radius: 0.5rem;
  font-weight: 700;
  font-size: 0.875rem;
  cursor: pointer;
  transition: transform 0.1s;
}

.challenge-btn:hover {
  transform: scale(1.05);
}

.challenge-btn:active {
  transform: scale(0.95);
}

/* Success Overlay */
.success-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.5);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
  backdrop-filter: blur(4px);
}

.success-overlay.active {
  display: flex;
  animation: fadeIn 0.3s ease-out;
}

.success-card {
  background: white;
  padding: 2rem;
  border-radius: 2rem;
  text-align: center;
  max-width: 90%;
  width: 20rem;
  animation: popIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

body.light-mode .success-card {
  background: var(--light-card);
  color: white;
}

.success-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  display: block;
  animation: bounce 1s infinite;
}

.success-title {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.success-btn {
  background: #10b981;
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 9999px;
  font-weight: 700;
  font-size: 1.125rem;
  margin-top: 1.5rem;
  cursor: pointer;
  width: 100%;
  transition: transform 0.1s;
}

.success-btn:hover {
  background: #059669;
  transform: scale(1.02);
}

/* Toggle Switch for Challenge Mode */
.challenge-toggle-btn {
  margin-bottom: 1rem;
  background: none;
  border: 2px solid #e2e8f0;
  padding: 0.5rem 1rem;
  border-radius: 9999px;
  font-weight: 600;
  color: var(--paint-text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s;
}

body.light-mode .challenge-toggle-btn {
  border-color: var(--light-border);
  color: var(--light-text-secondary);
}

.challenge-toggle-btn.active {
  border-color: #10b981;
  color: #10b981;
  background: rgba(16, 185, 129, 0.1);
}

/* Keyboard Navigation Focus Styles */
button:focus,
.color-btn:focus,
.hex-display:focus,
.share-btn:focus {
  outline: 2px solid #3b82f6;
  outline-offset: 2px;
}

body.light-mode button:focus,
body.light-mode .color-btn:focus,
body.light-mode .hex-display:focus,
body.light-mode .share-btn:focus {
  outline-color: #1d4ed8;
}

@keyframes slideDown {
  from {
    transform: translateY(-10px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}
@keyframes popIn {
  from {
    transform: scale(0.8);
    opacity: 0;
  }
  to {
    transform: scale(1);
    opacity: 1;
  }
}
@keyframes bounce {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

/* Keyboard Hints */
.keyboard-hint {
  display: block;
  font-size: 0.75rem;
  margin-top: 0.25rem;
  opacity: 0.6;
}

.kbd {
  display: inline-block;
  padding: 0.125rem 0.375rem;
  font-family: "Courier New", monospace;
  font-size: 0.7rem;
  font-weight: 600;
  border-radius: 0.25rem;
  margin: 0 0.125rem;
}

body.paint-mode .kbd {
  background: rgba(0, 0, 0, 0.1);
  border: 1px solid rgba(0, 0, 0, 0.2);
  color: var(--paint-text-secondary);
}

body.light-mode .kbd {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: var(--light-text-secondary);
}

/* Screen Reader Only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* Confetti Animation */
.result-blob.confetti::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(
    circle,
    rgba(255, 255, 255, 0.8) 1px,
    transparent 1px
  );
  background-size: 10px 10px;
  animation: confetti-fall 1s ease-out;
  pointer-events: none;
}

@keyframes confetti-fall {
  0% {
    opacity: 1;
    transform: translateY(0) rotate(0deg);
  }
  100% {
    opacity: 0;
    transform: translateY(50px) rotate(360deg);
  }
}

/* Enhanced Success Pulse */
.pulse-success {
  animation: pulse-success-animation 0.6s ease-out;
}

@keyframes pulse-success-animation {
  0% {
    transform: scale(1);
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7);
  }
  50% {
    transform: scale(1.15);
    box-shadow: 0 0 0 20px rgba(16, 185, 129, 0);
  }
  100% {
    transform: scale(1);
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0);
  }
}

/* Multi-color Confetti */
.result-blob.confetti::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle, #ff0000 1px, transparent 1px),
    radial-gradient(circle, #00ff00 1px, transparent 1px),
    radial-gradient(circle, #0000ff 1px, transparent 1px),
    radial-gradient(circle, #ffff00 1px, transparent 1px);
  background-size: 15px 15px, 20px 20px, 25px 25px, 30px 30px;
  background-position: 0 0, 5px 5px, 10px 10px, 15px 15px;
  animation: confetti-fall 1.5s infinite linear;
  pointer-events: none;
  opacity: 0.6;
}

/* Tutorial Overlay */
.tutorial-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  z-index: 1000;
  display: none;
}

.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1002;
  pointer-events: none;
}

.modal-content {
  background: var(--paint-card);
  padding: 2rem;
  border-radius: 12px;
  max-width: 400px;
  text-align: center;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  pointer-events: auto;
  position: relative;
}

body.light-mode .modal-content {
  background: var(--light-card);
}

.modal h2 {
  margin-bottom: 1rem;
  color: var(--paint-text-primary);
}

body.light-mode .modal h2 {
  color: var(--light-text-primary);
}

.modal p {
  margin-bottom: 1.5rem;
  color: var(--paint-text-secondary);
}

body.light-mode .modal p {
  color: var(--light-text-secondary);
}

.modal button {
  margin: 0 0.5rem;
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 6px;
  background: var(--paint-red);
  color: white;
  cursor: pointer;
  font-weight: 500;
}

.modal button:hover {
  background: #e63946;
}

.tutorial-highlight {
  position: relative;
  z-index: 1001;
  border-radius: 12px;
  box-shadow: 0 0 0 4px rgba(251, 191, 36, 0.95), 0 0 0 10px rgba(0, 0, 0, 0.35);
}

/* Educational Tooltip */
.edu-tooltip-container {
  position: relative;
  margin-top: 1rem;
  display: flex;
  justify-content: center;
}

.tooltip-btn {
  background: transparent;
  border: 2px solid var(--paint-text-secondary);
  color: var(--paint-text-secondary);
  padding: 0.5rem 1rem;
  border-radius: 2rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s;
}

.tooltip-btn:hover {
  background: rgba(0, 0, 0, 0.05);
  color: var(--paint-text-primary);
  border-color: var(--paint-text-primary);
}

body.light-mode .tooltip-btn {
  border-color: var(--light-text-secondary);
  color: var(--light-text-secondary);
}

body.light-mode .tooltip-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--light-text-primary);
  border-color: var(--light-text-primary);
}

.tooltip-content {
  position: absolute;
  bottom: 120%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--paint-card);
  border: 2px solid var(--paint-border);
  padding: 1rem;
  border-radius: 1rem;
  width: 280px;
  text-align: center;
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
  opacity: 0;
  visibility: hidden;
  transition: all 0.2s;
  z-index: 10;
  pointer-events: none;
}

.tooltip-content.active {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  bottom: 130%;
}

body.light-mode .tooltip-content {
  background: var(--light-card);
  border-color: var(--light-text-muted);
  color: var(--light-text-primary);
}

.tooltip-content::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  margin-left: -10px;
  border-width: 10px;
  border-style: solid;
  border-color: var(--paint-border) transparent transparent transparent;
}

body.light-mode .tooltip-content::after {
  border-color: var(--light-text-muted) transparent transparent transparent;
}

/* Reduced Motion Support */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .equation-text {
    animation: none !important;
  }

  .result-blob .shine {
    opacity: 0 !important;
  }

  .color-btn.active {
    box-shadow: none !important;
  }
}

/* --- ACHIEVEMENTS --- */
.achievement-toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: white;
  color: #1e293b;
  padding: 1rem 1.5rem;
  border-radius: 1rem;
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1),
    0 8px 10px -6px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  gap: 1rem;
  z-index: 2000;
  transform: translateY(150%);
  transition: transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  border: 2px solid #3b82f6;
}

.achievement-toast.active {
  transform: translateY(0);
}

.achievement-icon {
  font-size: 2rem;
}

.achievement-text {
  display: flex;
  flex-direction: column;
}

.achievement-title {
  font-weight: 700;
  font-size: 1rem;
  color: #3b82f6;
}

.achievement-desc {
  font-size: 0.875rem;
  color: #64748b;
}

/* --- LEVEL UP ANIMATIONS --- */
@keyframes level-up-glow {
  0%,
  100% {
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.5);
  }
  50% {
    box-shadow: 0 0 50px rgba(59, 130, 246, 0.8),
      0 0 100px rgba(59, 130, 246, 0.4);
  }
}

.level-up-active {
  animation: level-up-glow 1.5s ease infinite;
  border: 4px solid #3b82f6 !important;
  transform: scale(1.05);
}

@keyframes bounce-in {
  0% {
    transform: scale(0.3);
    opacity: 0;
  }
  50% {
    transform: scale(1.05);
    opacity: 1;
  }
  70% {
    transform: scale(0.9);
  }
  100% {
    transform: scale(1);
  }
}

.animate-bounce-in {
  animation: bounce-in 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes rainbow-text {
  0% {
    color: #ff0000;
  }
  20% {
    color: #ffff00;
  }
  40% {
    color: #00ff00;
  }
  60% {
    color: #00ffff;
  }
  80% {
    color: #0000ff;
  }
  100% {
    color: #ff00ff;
  }
}

.rainbow-text {
  animation: rainbow-text 2s linear infinite;
  font-weight: 800;
}

/* ====================
   Achievement Toast
   ==================== */

.achievement-toast {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  /* Darkened green for better contrast (WCAG AA - requires >4.5:1) */
  background: linear-gradient(135deg, #047857 0%, #065f46 100%);
  color: white;
  padding: 16px 20px;
  border-radius: 16px;
  box-shadow: 0 10px 40px rgba(16, 185, 129, 0.4);
  animation: toastSlideIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275),
    toastFadeOut 0.3s ease 3s forwards;
  z-index: 9999;
  max-width: 320px;
}

.achievement-icon {
  font-size: 2.5rem;
  animation: achievementBounce 0.6s ease;
}

.achievement-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.achievement-text strong {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  opacity: 0.9;
}

.achievement-text span {
  font-size: 1.125rem;
  font-weight: 700;
}

@keyframes toastSlideIn {
  from {
    transform: translateX(100%) scale(0.8);
    opacity: 0;
  }
  to {
    transform: translateX(0) scale(1);
    opacity: 1;
  }
}

@keyframes toastFadeOut {
  from {
    opacity: 1;
    transform: translateX(0);
  }
  to {
    opacity: 0;
    transform: translateX(20px);
  }
}

@keyframes achievementBounce {
  0%,
  100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.2);
  }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
  .achievement-toast {
    animation: none;
    opacity: 1;
  }

  .achievement-icon {
    animation: none;
  }
}

/* Dark mode / Light mode variants */
body.light-mode .achievement-toast {
  /* Darkened blue for better contrast (WCAG AA) */
  background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
  box-shadow: 0 10px 40px rgba(59, 130, 246, 0.5);
}

/* --- ACHIEVEMENT GALLERY --- */
.achievements-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
  margin: 2rem 0;
}

@media (min-width: 640px) {
  .achievements-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.achievement-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 1.5rem;
  border-radius: 1rem;
  background: #f8fafc;
  border: 2px solid transparent;
  transition: all 0.3s ease;
  text-align: center;
}

.achievement-item.locked {
  opacity: 0.5;
  filter: grayscale(1);
  background: #f1f5f9;
}

.achievement-item.unlocked {
  background: white;
  border-color: #3b82f6;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}

.achievement-item-icon {
  font-size: 2.5rem;
  margin-bottom: 0.25rem;
}

.achievement-item-name {
  font-weight: 700;
  font-size: 0.875rem;
  color: #1e293b;
}

.achievement-item-desc {
  font-size: 0.75rem;
  color: #64748b;
  line-height: 1.2;
}

#achievements-close {
  width: 100%;
  padding: 1rem;
  border-radius: 0.75rem;
  background: #3b82f6;
  color: white;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
}

#achievements-close:hover {
  background: #2563eb;
}

.secondary-btn {
  width: 100%;
  padding: 1rem;
  border-radius: 0.75rem;
  background: #f1f5f9;
  color: #475569;
  font-weight: 700;
  border: 2px solid #e2e8f0;
  cursor: pointer;
  transition: all 0.2s;
}

.secondary-btn:hover {
  background: #e2e8f0;
  color: #1e293b;
}

/* Dark mode adjustments */
body.light-mode .achievement-item.unlocked {
  background: #1e293b;
  color: white;
  border-color: #3b82f6;
}

body.light-mode .achievement-item-name {
  color: white;
}

body.light-mode .achievement-item-desc {
  color: #94a3b8;
}

body.light-mode .achievement-item.locked {
  background: #334155;
}

/* ====================
   Language Selector
   ==================== */

.language-selector {
  position: relative;
  margin-top: 0.75rem;
}

.lang-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid rgba(0, 0, 0, 0.1);
  border-radius: 9999px;
  background: rgba(255, 255, 255, 0.1);
  color: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.lang-btn:hover {
  background: rgba(255, 255, 255, 0.2);
}

body.light-mode .lang-btn {
  border-color: rgba(255, 255, 255, 0.2);
  color: var(--light-text-secondary);
}

body.light-mode .lang-btn:hover {
  background: rgba(255, 255, 255, 0.15);
}

.lang-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  margin-top: 0.5rem;
  background: white;
  border-radius: 0.75rem;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
  overflow: hidden;
  z-index: 1000;
  min-width: 140px;
}

body.light-mode .lang-menu {
  background: var(--light-card);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
}

.lang-option {
  display: block;
  width: 100%;
  padding: 0.75rem 1rem;
  border: none;
  background: none;
  color: #1e293b;
  font-size: 0.875rem;
  font-weight: 500;
  text-align: left;
  cursor: pointer;
  transition: background 0.15s ease;
}

.lang-option:hover {
  background: #f1f5f9;
}

body.light-mode .lang-option {
  color: white;
}

body.light-mode .lang-option:hover {
  background: rgba(255, 255, 255, 0.1);
}

.lang-option:not(:last-child) {
  border-bottom: 1px solid #e2e8f0;
}

body.light-mode .lang-option:not(:last-child) {
  border-bottom-color: rgba(255, 255, 255, 0.1);
}