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

html,
body {
  height: 100%;
  overflow: hidden;
  background-color: #000;
  color: #fff;
  font-family: system-ui, -apple-system, sans-serif;
  user-select: none;
  -webkit-user-select: none;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
}

main {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  z-index: 10;
  pointer-events: none;
}

body.dragging {
  user-select: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  cursor: grabbing;
}

/* Paint mode cursor changes */
body.paint-active {
  cursor: crosshair;
}

body.erase-active {
  cursor: cell;
}

body.paint-active #paint-canvas,
body.erase-active #paint-canvas {
  z-index: 15;
}

#title {
  font-size: clamp(2rem, 8vw, 4rem);
  font-weight: 300;
  letter-spacing: 0.08em;
  cursor: pointer;
  pointer-events: auto;
  user-select: none;
  transition: opacity 0.3s ease;
}

#title:hover {
  opacity: 0.7;
}

.hint {
  margin-top: 1rem;
  font-size: 0.75rem;
  opacity: 0.3;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  transition: opacity 0.5s ease;
  pointer-events: none;
}

.hint.hidden {
  opacity: 0;
}

/* Physics letters */
.letter {
  position: absolute;
  font-size: clamp(2rem, 8vw, 4rem);
  font-weight: 300;
  letter-spacing: 0.08em;
  color: #fff;
  user-select: none;
  cursor: grab;
  z-index: 20;
  will-change: transform;
  transition: color 0.2s ease;
}

.letter:active {
  cursor: grabbing;
}

.letter.fading {
  transition: opacity 0.8s ease, transform 0.8s ease;
  opacity: 0;
}

/* Paint Canvas (Background) */
#paint-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  pointer-events: none;
}

/* Canvas for trails */
#canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 5;
  pointer-events: none;
}

/* Reset button */
#reset-btn {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  padding: 0.75rem 1.5rem;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #fff;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 4px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.3s ease, border-color 0.2s ease, background 0.2s ease;
  z-index: 100;
}

#reset-btn.visible {
  opacity: 1;
}

#reset-btn:hover {
  border-color: #fff;
  background: rgba(255, 255, 255, 0.1);
}

#reset-btn.holding {
  transform: scale(0.95);
  background: #333;
  animation: flash-red 0.5s ease-in-out infinite;
}

@keyframes flash-red {

  0%,
  100% {
    border-color: rgba(255, 100, 100, 0.5);
    background: rgba(255, 50, 50, 0.2);
    color: #ff6666;
  }

  50% {
    border-color: rgba(255, 50, 50, 1);
    background: rgba(255, 50, 50, 0.4);
    color: #ff3333;
  }
}

#reset-btn.blink {
  background: #ff6b6b !important;
  border-color: #ff3333;
}

/* ===== Easter Egg Menu ===== */
.egg-menu {
  position: fixed;
  top: 1rem;
  right: 1rem;
  display: flex;
  gap: 0.5rem;
  z-index: 200;
}

.egg-btn {
  padding: 0.5rem 1rem;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.6);
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.egg-btn:hover {
  color: #fff;
  border-color: rgba(255, 255, 255, 0.5);
}

.egg-btn.active {
  color: #000;
  background: #fff;
  border-color: #fff;
}

.egg-btn.disabled {
  opacity: 0.3;
  cursor: not-allowed;
  pointer-events: none;
}

/* ===== Hamburger Button ===== */
.hamburger-btn {
  position: fixed;
  top: 1rem;
  right: 1rem;
  width: 40px;
  height: 40px;
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 4px;
  cursor: pointer;
  z-index: 300;
  transition: border-color 0.2s ease;
}

.hamburger-btn:hover {
  border-color: rgba(255, 255, 255, 0.6);
}

.hamburger-btn span {
  display: block;
  width: 18px;
  height: 2px;
  background: #fff;
  transition: all 0.3s ease;
}

.hamburger-btn.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.hamburger-btn.active span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.hamburger-btn.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ===== Side Panel ===== */
.side-panel {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 250;
  pointer-events: none;
}

.side-panel.open {
  pointer-events: auto;
}

.side-panel-overlay {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background: rgba(0, 0, 0, 0.5);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.side-panel.open .side-panel-overlay {
  opacity: 1;
}

.side-panel-content {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: min(280px, 80vw);
  background: #111;
  padding: 4rem 1.5rem 2rem;
  transform: translateX(100%);
  transition: transform 0.3s ease;
  overflow-y: auto;
}

.side-panel.open .side-panel-content {
  transform: translateX(0);
}

.side-panel-content h3 {
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.4);
  margin-bottom: 1rem;
}

.side-panel-content .egg-btn {
  display: block;
  width: 100%;
  text-align: left;
  margin-bottom: 0.5rem;
}

/* ===== Discovery Flash ===== */
.discovery-flash {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0.8);
  padding: 1rem 2rem;
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #000;
  background: #fff;
  border-radius: 8px;
  opacity: 0;
  z-index: 500;
  pointer-events: auto;
  cursor: grab;
  transition: all 0.3s ease;
}

.discovery-flash.visible {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1);
}

/* ===== Confetti ===== */
.confetti {
  position: fixed;
  top: 45%;
  width: 40px;
  height: 40px;
  padding: 15px;
  background-clip: content-box;
  border-radius: 2px;
  z-index: 600;
  pointer-events: none;
  animation: confetti-fall 1.5s ease-out forwards;
}

@keyframes confetti-fall {
  0% {
    transform: translateY(0) translateX(0) rotate(0deg);
    opacity: 1;
  }

  100% {
    transform: translateY(300px) translateX(var(--x, 0)) rotate(var(--r, 360deg));
    opacity: 0;
  }
}