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

body {
  font-family: 'Segoe UI', sans-serif;
  background: #1a1a2e;
  overflow: hidden;
}

/* ── TOP BAR ── */
.topbar {
  position: fixed;
  top: 0;
  width: 100%;
  height: 54px;
  background: #16213e;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  z-index: 10;
  border-bottom: 2px solid #7c3aed;
}

.title {
  font-weight: 700;
  font-size: 18px;
  color: #ffffff;
  letter-spacing: 1px;
}

#pageNum {
  font-size: 13px;
  color: #7c3aed;
  background: #0f3460;
  padding: 4px 12px;
  border-radius: 20px;
  font-weight: 600;
  border: 1px solid #7c3aed;
}

/* ── CANVAS AREA ── */
.canvas-container {
  position: fixed;
  top: 54px;
  bottom: 64px;
  width: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  background: #fdfaf3;
}

canvas {
  display: block;
  background: repeating-linear-gradient(
    #fdfaf3,
    #fdfaf3 31px,
    #c9d4e8 32px
  );
}

/* ── BOTTOM BAR ── */
.bottombar {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 64px;
  background: #16213e;
  border-top: 2px solid #7c3aed;
  display: flex;
  align-items: center;
  justify-content: space-around;
  padding: 0 8px;
  z-index: 10;
  overflow-x: auto;
}

/* ── BUTTONS ── */
button {
  border: 1px solid #7c3aed;
  background: #0f3460;
  color: #ffffff;
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  min-width: 36px;
  height: 42px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

button:active {
  background: #7c3aed;
  transform: scale(0.95);
}

button:nth-child(1) {
  background: #ffffff;
  color: #000000;
  border-color: #cccccc;
}

button:nth-child(2) {
  background: #fff0f0;
  color: #ef4444;
  border-color: #ef4444;
}

button:nth-last-child(1),
button:nth-last-child(2) {
  background: #7c3aed;
  border-color: #a78bfa;
}

button.active-eraser {
  background: #7c3aed;
  border-color: #a78bfa;
}