:root {
  --main-bg: #e0e0e0;
  --shadow-light: #ffffff;
  --shadow-dark: #bebebe;
  --text: #333;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--main-bg);
  font-family: 'Segoe UI', sans-serif;
  color: var(--text);
  min-height: 100vh;
  overflow: auto;
}

#layout {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 40px 0;
  background: var(--main-bg);
}

#container {
  display: flex;
  width: 1140px; /* 250 + 800 + 60 + 300 */
  border-radius: 20px;
  box-shadow:
    10px 10px 20px var(--shadow-dark),
    -10px -10px 20px var(--shadow-light);
  background: var(--main-bg);
}

#sketch-wrapper {
  width: 800; /* 250px buffer + 800px canvas + 60px gap */
  display: flex;
  align-items: center;
  justify-content: flex-start;
  padding-left: 0;
  background: var(--main-bg);
  border-top-left-radius: 20px;
  border-bottom-left-radius: 20px;
  box-shadow:
    inset 8px 8px 16px var(--shadow-dark),
    inset -8px -8px 16px var(--shadow-light);
}


#sketch-holder {
  width: 800px;
  height: 800px;
  display: flex;
  align-items: center;
  justify-content: center;
}

canvas {
  border-radius: 20px;
  background: var(--main-bg);
  box-shadow:
    8px 8px 16px var(--shadow-dark),
    -8px -8px 16px var(--shadow-light);
}

#controls {
  flex: 0 0 300px;
  padding: 24px;
  background: var(--main-bg);
  border-top-right-radius: 20px;
  border-bottom-right-radius: 20px;
  box-shadow:
    inset 4px 4px 8px var(--shadow-dark),
    inset -4px -4px 8px var(--shadow-light);
}

h3 {
  margin-top: 16px;
  font-size: 16px;
}

label {
  display: block;
  margin-bottom: 14px;
  font-size: 14px;
}

input[type="range"],
input[type="checkbox"] {
  width: 100%;
  margin-top: 4px;
  background: var(--main-bg);
  border-radius: 10px;
  box-shadow:
    inset 4px 4px 6px var(--shadow-dark),
    inset -4px -4px 6px var(--shadow-light);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  height: 16px;
  width: 16px;
  background: var(--main-bg);
  border-radius: 50%;
  box-shadow:
    2px 2px 5px var(--shadow-dark),
    -2px -2px 5px var(--shadow-light);
  cursor: pointer;
}

input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin-right: 6px;
  cursor: pointer;
}

button {
  margin-top: 20px;
  padding: 10px;
  width: 100%;
  background: var(--main-bg);
  border: none;
  border-radius: 12px;
  box-shadow:
    4px 4px 8px var(--shadow-dark),
    -4px -4px 8px var(--shadow-light);
  cursor: pointer;
  tran