*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  min-height: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: radial-gradient(circle at top, #fef3c7, #e0e7ff);
  color: #0f172a;
  transition: background 200ms ease, color 200ms ease;
}

body.theme-dark {
  background: linear-gradient(160deg, #0f172a, #1e293b 60%, #0f172a);
  color: #e2e8f0;
}

body.theme-dark .app {
  background: rgba(15, 23, 42, 0.9);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.55);
}

body.theme-dark .chip {
  background: rgba(51, 65, 85, 0.65);
  color: #e2e8f0;
}

body.theme-dark .color-btn {
  color: #0f172a;
}

body.theme-colorful {
  background: linear-gradient(135deg, #fce7f3, #cffafe, #fef3c7);
  color: #0f172a;
}

body.theme-colorful .app {
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 25px 80px rgba(244, 63, 94, 0.25);
}

.app {
  width: min(95vw, 960px);
  margin: clamp(1rem, 2vw, 2.5rem) auto;
  padding: clamp(1.25rem, 3vw, 3rem);
  background: rgba(255, 255, 255, 0.9);
  border-radius: 32px;
  box-shadow: 0 30px 90px rgba(15, 23, 42, 0.15);
  backdrop-filter: blur(8px);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

header {
  text-align: center;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 3rem);
}

.subtitle {
  margin: 0.25rem 0 0;
  color: #475569;
}

.stats {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

.chip {
  padding: 0.65rem 1.5rem;
  border-radius: 999px;
  background: #e2e8f0;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.controls-inline {
  gap: 0.5rem;
}

.theme-select {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 600;
}

.theme-select select {
  border: none;
  border-radius: 999px;
  padding: 0.35rem 0.75rem;
  font-weight: 600;
  cursor: pointer;
  background: #fff;
}

.icon-btn {
  border: none;
  border-radius: 999px;
  padding: 0.45rem 0.9rem;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  background: #2563eb;
  color: #fff;
  transition: transform 0.15s ease, filter 0.15s ease;
}

.icon-btn[aria-pressed="true"] {
  background: #0f172a;
}

.icon-btn:active {
  transform: scale(0.96);
}

.ghost-icon {
  background: transparent;
  color: inherit;
  border: 2px solid rgba(148, 163, 184, 0.7);
}

.ghost-icon:hover {
  filter: brightness(1.1);
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  align-items: center;
}

.drawer-toggle {
  position: fixed;
  top: 1rem;
  left: 1rem;
  z-index: 20;
  border: none;
  border-radius: 50%;
  width: 54px;
  height: 54px;
  font-size: 1.4rem;
  cursor: pointer;
  background: #0f172a;
  color: #fff;
  box-shadow: 0 12px 25px rgba(15, 23, 42, 0.35);
}

.drawer {
  position: fixed;
  inset: 0 auto 0 0;
  width: clamp(240px, 60vw, 320px);
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 8px 0 25px rgba(15, 23, 42, 0.25);
  padding: 1.75rem 1.5rem;
  transform: translateX(-105%);
  transition: transform 240ms ease;
  z-index: 30;
  overflow-y: auto;
}

body.theme-dark .drawer {
  background: rgba(15, 23, 42, 0.95);
  color: #e2e8f0;
}

body.theme-colorful .drawer {
  background: rgba(255, 255, 255, 0.95);
}

.drawer.open {
  transform: translateX(0);
}

.drawer-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.4);
  z-index: 25;
  transition: opacity 200ms ease;
}

.drawer-backdrop.hidden {
  opacity: 0;
  pointer-events: none;
}

body.drawer-open {
  overflow: hidden;
}

.drawer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.drawer-section {
  margin-bottom: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.drawer-label {
  margin: 0;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #64748b;
}

body.theme-dark .drawer-label {
  color: #94a3b8;
}

.reset-btn.full,
.ghost-btn.full {
  width: 100%;
  text-align: center;
}

.color-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(60px, 1fr));
  gap: 0.5rem;
  min-width: 240px;
  width: min(360px, 100%);
}

.color-btn {
  border: none;
  border-radius: 999px;
  color: #fff;
  font-weight: 600;
  padding: 0.8rem 0;
  min-height: 52px;
  font-size: 1rem;
  cursor: pointer;
  transition: transform 0.15s ease, filter 0.15s ease;
  touch-action: manipulation;
}

.color-btn:hover {
  transform: translateY(-2px);
  filter: brightness(1.15);
}

.color-btn:focus-visible {
  outline: 3px solid rgba(255, 255, 255, 0.7);
  outline-offset: 3px;
}

.color-btn.active {
  opacity: 0.6;
  pointer-events: none;
}

.color-btn.hint {
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.9), 0 0 15px rgba(244, 63, 94, 0.7);
}

.reset-btn {
  border: none;
  background: #1e293b;
  color: #fff;
  font-weight: 600;
  padding: 0.9rem 2rem;
  border-radius: 12px;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.reset-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 15px 30px rgba(30, 41, 59, 0.35);
}

.board-wrapper {
  display: flex;
  justify-content: center;
}

.board {
  width: min(80vmin, 520px);
  max-height: min(80vmin, 520px);
  aspect-ratio: 1;
  display: grid;
  gap: 4px;
  padding: 8px;
  border-radius: 24px;
  background: #cbd5f5;
  box-shadow: inset 0 4px 12px rgba(15, 23, 42, 0.35);
  overflow: hidden;
}

.tile {
  border-radius: 20%;
  transform: scale(0.2);
  opacity: 0;
  animation: tileEnter 400ms ease forwards;
  transition: background-color 180ms ease;
}

.tile.flooding {
  animation: pulse 320ms ease;
}

@keyframes tileEnter {
  0% {
    transform: scale(0.2);
    opacity: 0;
  }
  100% {
    transform: scale(1);
    opacity: 1;
  }
}

@keyframes pulse {
  0% {
    transform: scale(0.7);
  }
  60% {
    transform: scale(1.05);
  }
  100% {
    transform: scale(1);
  }
}

.overlay,
.tutorial {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(6px);
  transition: opacity 200ms ease;
}

.hidden {
  opacity: 0;
  pointer-events: none;
}

.overlay-card,
.tutorial-card {
  background: #fff;
  padding: 2rem;
  width: min(90vw, 360px);
  border-radius: 20px;
  text-align: center;
  box-shadow: 0 25px 60px rgba(15, 23, 42, 0.35);
}

.overlay-card button,
.tutorial-card button {
  margin-top: 1.25rem;
  padding: 0.85rem 1.75rem;
  border: none;
  border-radius: 12px;
  background: #2563eb;
  color: #fff;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.overlay-card button:hover,
.tutorial-card button:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 20px rgba(37, 99, 235, 0.35);
}

.tutorial-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

.ghost-btn {
  border: 2px solid #2563eb;
  background: transparent;
  color: inherit;
  padding: 0.75rem 1.5rem;
  border-radius: 12px;
  font-weight: 600;
  cursor: pointer;
}

.ghost-btn:hover {
  background: rgba(37, 99, 235, 0.15);
}

#particles {
  position: fixed;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.spark {
  position: absolute;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  opacity: 0;
  animation: spark 700ms ease-out forwards;
}

@keyframes spark {
  0% {
    opacity: 1;
    transform: scale(0.5);
  }
  100% {
    opacity: 0;
    transform: translate(var(--dx), var(--dy)) scale(0.2);
  }
}

@media (max-width: 640px) {
  body {
    padding: 1rem;
  }

  .app {
    width: 100%;
    margin: 0.5rem;
    border-radius: 24px;
  }

  .stats {
    flex-direction: column;
  }

  .controls {
    flex-direction: column;
    width: 100%;
  }

  .color-buttons {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    width: 100%;
  }

  .color-btn {
    font-size: 1.1rem;
    min-height: 56px;
  }

  .board {
    width: min(92vw, 92vmin);
    max-height: min(92vw, 92vmin);
    gap: 3px;
  }

  .chip {
    width: 100%;
    text-align: center;
  }
}

@media (max-height: 520px) and (orientation: landscape) {
  body {
    align-items: flex-start;
  }
  .app {
    flex-direction: row;
    gap: 1rem;
    align-items: center;
  }
  .board-wrapper {
    flex: 1;
  }
  .board {
    width: min(60vh, 60vmin);
    max-height: min(60vh, 60vmin);
  }
}

.tile.flash {
  animation: flash 450ms ease alternate 2;
}

@keyframes flash {
  0% {
    filter: brightness(1);
  }
  50% {
    filter: brightness(1.4);
  }
  100% {
    filter: brightness(1);
  }
}