* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  display: flex;
  height: 100vh;
  background: #f5f5f7;
  overflow: hidden;
}

/* ЛІВА ПАНЕЛЬ */
#tools {
  width: 80px;
  background: #ffffff;
  box-shadow: 3px 0 10px rgba(0,0,0,0.1);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px 0;
  gap: 15px;
}

.tool {
  width: 50px;
  height: 50px;
  border-radius: 12px;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  font-size: 24px;
  transition: 0.2s;
  user-select: none;
}

.tool:hover {
  background: #e0e0e0;
}

.tool.active {
  background: #4a90e2;
  color: white;
}

/* CANVAS */
#canvas-container {
  flex-grow: 1;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #e0e0e0;
  overflow: hidden;
}

canvas {
  max-width: 100%;
  max-height: 100%;
  width: 100%;
  height: 100%;
  background: #ffffff;
  border-radius: 12px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  cursor: crosshair;
}


/* ПРАВА ПАНЕЛЬ */
#settings {
  width: 280px;
  height: 100vh;
  background: #ffffff;
  box-shadow: -3px 0 10px rgba(0,0,0,0.1);
  display: flex;
  flex-direction: column;
  padding: 20px;
}

#settings h2 {
  margin: 0 0 15px;
  text-align: center;
  font-size: 18px;
  color: #333;
}

#settings h3 {
  margin: 10px 0 5px;
  font-size: 15px;
  color: #444;
}

/* ПРОКРУТКА */
.settings-content {
  flex-grow: 1;
  overflow-y: auto;
  padding-right: 6px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* ГРУПИ */
.setting-group {
  background: #f6f7f9;
  padding: 12px;
  border-radius: 10px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.checkbox-group {
  background: transparent;
  padding: 0;
}

label {
  font-size: 13px;
  font-weight: 600;
  color: #555;
}

input[type="number"],
input[type="file"],
input[type="range"],
textarea {
  width: 100%;
  padding: 8px;
  border-radius: 6px;
  border: 1px solid #ccc;
  font-size: 14px;
}

textarea {
  resize: vertical;
  font-family: monospace;
}

input:focus,
textarea:focus {
  outline: none;
  border-color: #4a90e2;
}

/* КНОПКИ */
button {
  width: 100%;
  padding: 10px;
  border: none;
  border-radius: 8px;
  background: #4a90e2;
  color: white;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

button:hover {
  background: #357ab8;
  transform: translateY(-1px);
}

button:active {
  transform: translateY(0);
}

/* SCROLLBAR */
.settings-content::-webkit-scrollbar {
  width: 6px;
}

.settings-content::-webkit-scrollbar-thumb {
  background: #c0c4cc;
  border-radius: 10px;
}

.test-level-btn {
  position: fixed;
  bottom: 20px;
  left: 35%;
  width: 220px;
  z-index: 1000;
}