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

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: Arial, Helvetica, sans-serif;
  background: #f4f7fb;
}

/* Main app wrapper */
.app {
  width: 100vw;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Toolbar */
.toolbar {
  height: 80px;
  background: linear-gradient(135deg, #1f2937, #111827);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  box-shadow: 0 4px 18px rgba(0, 0, 0, 0.18);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

/* Common tool group */
.tool-group {
  display: flex;
  align-items: center;
  gap: 12px;
  background: rgba(255, 255, 255, 0.08);
  padding: 10px 14px;
  border-radius: 14px;
  backdrop-filter: blur(8px);
}

/* Color boxes */
.colors {
  gap: 10px;
}

.color-box {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  cursor: pointer;
  border: 3px solid transparent;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.color-box:hover {
  transform: scale(1.12);
  border-color: #ffffff;
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.15);
}

.color-box.black {
  background: #111111;
}

.color-box.red {
  background: #ef4444;
}

.color-box.blue {
  background: #3b82f6;
}

.color-box.green {
  background: #22c55e;
}

/* Brush size */
.brush-size {
  color: #ffffff;
  font-size: 15px;
  font-weight: 600;
  gap: 10px;
}

.brush-size label {
  letter-spacing: 0.3px;
}

.brush-size input[type="range"] {
  width: 180px;
  accent-color: #60a5fa;
  cursor: pointer;
}

/* Eraser button */
.eraser button {
  width: 46px;
  height: 46px;
  border: none;
  border-radius: 12px;
  background: #ffffff;
  font-size: 22px;
  cursor: pointer;
  display: grid;
  place-items: center;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.18);
  transition: transform 0.2s ease, 0.2s ease;
}

.eraser button:hover {
  transform: translateY(-2px) scale(1.05);
  background: #fef3c7;
}

/* Drawing board */
#drawing-board {
  flex: 1;
  width: 100%;
  height: calc(100vh - 80px);
  display: block;
  background: #ffffff;
  cursor: crosshair;
}

/* Optional: selected color effect later in JS */
.color-box.active {
  border-color: #ffffff;
  box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.2);
  transform: scale(1.08);
}

/* Responsive */
@media (max-width: 768px) {
  .toolbar {
    height: auto;
    padding: 14px;
    flex-direction: column;
    gap: 12px;
    align-items: stretch;
  }

  .tool-group {
    justify-content: center;
    flex-wrap: wrap;
  }

  .brush-size input[type="range"] {
    width: 140px;
  }

  #drawing-board {
    height: calc(100vh - 140px);
  }
}