:root {
  --theme-color: #1c1a99;
}

body {
  font-family: 'Arial', sans-serif;
  background-color: #f4f4f4;
  margin: 0;
  padding: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

#whiteboard-container {
  max-width: 900px;
  margin: 50px auto;
  padding: 20px;
  background-color: #fff;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  flex: 1;
}

#whiteboard-header {
  text-align: center;
  font-size: 24px;
  font-weight: bold;
  margin-bottom: 15px;
  color: var(--theme-color);
}

/* Toolbar */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  padding: 10px;
  background-color: #f9f9f9;
  border-radius: 4px;
  margin-bottom: 15px;
}

.tool-group {
  display: flex;
  align-items: center;
  gap: 6px;
}

.toolbar button {
  padding: 8px 12px;
  font-size: 14px;
  background-color: var(--theme-color);
  color: #fff;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.toolbar button:hover {
  background-color: #0d0c5f;
}

.tool-btn {
  position: relative;
}

.tool-btn.active {
  outline: 2px solid #333;
  outline-offset: 2px;
}

#stroke-color {
  width: 36px;
  height: 36px;
  border: 1px solid #ccc;
  border-radius: 4px;
  cursor: pointer;
  padding: 2px;
}

.width-label {
  font-size: 13px;
  color: #666;
}

#stroke-width {
  width: 80px;
  cursor: pointer;
  accent-color: var(--theme-color);
}

#width-value {
  font-size: 13px;
  color: #666;
  min-width: 20px;
}

/* Canvas */
.canvas-wrapper {
  border: 1px solid #ccc;
  border-radius: 4px;
  overflow: hidden;
  cursor: crosshair;
}

#draw-canvas {
  display: block;
  background-color: #fff;
}

/* Toast */
#toast {
  position: fixed;
  top: 40px;
  right: 40px;
  background-color: rgba(0, 0, 0, 0.8);
  color: #fff;
  padding: 10px 20px;
  border-radius: 4px;
  opacity: 0;
  transition: opacity 0.3s ease;
}

#theme-color-picker {
  position: absolute;
  top: 10px;
  right: 10px;
}

/* Footer */
.footer {
  text-align: center;
  padding: 10px 0;
  background-color: var(--theme-color);
  color: #fff;
  font-size: 14px;
  margin-top: auto;
}

.footer a {
  color: #fff;
  text-decoration: none;
  font-weight: bold;
}

.footer a:hover {
  text-decoration: underline;
}

a.external::after {
  content: "\2197";
  margin-left: 4px;
}

/* Fullscreen mode */
#whiteboard-container.fullscreen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  max-width: none;
  margin: 0;
  padding: 0;
  border-radius: 0;
  box-shadow: none;
  z-index: 9999;
  display: flex;
  flex-direction: column;
}

#whiteboard-container.fullscreen .toolbar {
  border-radius: 0;
  margin-bottom: 0;
  flex-shrink: 0;
}

#whiteboard-container.fullscreen .canvas-wrapper {
  flex: 1;
  border: none;
  border-radius: 0;
}

@media screen and (max-width: 768px) {
  #whiteboard-container {
    margin: 20px 10px;
    padding: 10px;
  }

  .toolbar {
    gap: 8px;
  }

  #stroke-width {
    width: 60px;
  }

  #whiteboard-header {
    font-size: 20px;
  }
}

@media screen and (max-width: 480px) {
  #whiteboard-container {
    margin: 10px 5px;
    padding: 8px;
  }

  #whiteboard-header {
    font-size: 18px;
    margin-bottom: 10px;
  }

  .toolbar {
    gap: 6px;
    padding: 8px;
  }

  .tool-group {
    flex-wrap: wrap;
    gap: 4px;
  }

  .toolbar button {
    padding: 10px 12px;
    font-size: 13px;
    min-height: 40px;
  }

  #stroke-color {
    width: 40px;
    height: 40px;
  }

  #stroke-width {
    width: 50px;
  }

  .width-label {
    display: none;
  }

  #toast {
    right: 10px;
    top: 10px;
    font-size: 13px;
  }

  .footer {
    font-size: 12px;
    padding: 8px 10px;
  }
}