:root {
  --bg: #050505; --bg-raised: #0c0c0c; --ink: #fafafa; --ink-dim: #a6a6a6;
  --ink-faint: #4a4a4a; --rule: #1f1f1f; --red: #fb2c36; --red-deep: #8f1820;
  --sans: 'Inter', system-ui, sans-serif; --mono: 'JetBrains Mono', monospace;
  --serif: 'Fraunces', serif;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { background: var(--bg); color: var(--ink); font-family: var(--sans); min-height: 100vh; -webkit-font-smoothing: antialiased; }

nav {
  padding: 20px 32px; display: flex; justify-content: space-between; align-items: center;
  font-family: var(--mono); font-size: 11px; color: var(--ink-dim);
  letter-spacing: 0.08em; text-transform: uppercase;
}
nav .brand { color: var(--ink); font-weight: 500; }
nav .brand em { color: var(--red); font-style: normal; font-weight: 500; }
nav .breadcrumb { color: var(--ink-faint); }
nav .breadcrumb span { margin: 0 8px; }
nav a { color: var(--ink-dim); text-decoration: none; }
nav a:hover { color: var(--red); }

.opening { max-width: 720px; margin: 24px auto 28px; padding: 0 32px; }
.chapter {
  font-family: var(--mono); font-size: 11px; color: var(--red);
  letter-spacing: 0.25em; text-transform: uppercase; margin-bottom: 18px;
}
h1 {
  font-weight: 300; font-size: clamp(36px, 5vw, 56px);
  line-height: 0.98; letter-spacing: -0.03em; margin-bottom: 20px;
}
h1 em { font-family: var(--serif); font-style: italic; color: var(--red); font-weight: 300; }
.opening p { font-size: 15px; color: var(--ink-dim); line-height: 1.65; }

.instrument {
  max-width: 1080px; margin: 0 auto 16px; padding: 0 32px; position: relative;
}
#scope {
  display: block; width: 100%; height: 62vh; min-height: 380px; max-height: 640px;
  background: #050505; border: 1px solid var(--rule); border-radius: 10px;
}
.pen-overlay {
  position: fixed; width: 8px; height: 8px; margin-left: -4px; margin-top: -4px;
  background: var(--red); border-radius: 50%;
  box-shadow: 0 0 6px var(--red), 0 0 14px rgba(251,44,54,0.5);
  pointer-events: none; opacity: 0; transition: opacity 0.25s; z-index: 5;
}

.controls {
  max-width: 1080px; margin: 0 auto 40px; padding: 16px 18px;
  background: var(--bg-raised); border: 1px solid var(--rule); border-radius: 10px;
  position: relative; margin-left: auto; margin-right: auto;
}
.controls { margin-left: 32px; margin-right: 32px; max-width: calc(1080px - 64px); }

.presets {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
  padding-bottom: 12px; margin-bottom: 12px; border-bottom: 1px solid var(--rule);
}
.ctrl-label {
  font-family: var(--mono); font-size: 10px; color: var(--red);
  letter-spacing: 0.2em; text-transform: uppercase; margin-right: 8px;
}
.preset-btn {
  background: transparent; border: 1px solid var(--rule); color: var(--ink-dim);
  padding: 6px 12px; border-radius: 4px;
  font-family: var(--mono); font-size: 10px; letter-spacing: 0.1em; text-transform: uppercase;
  cursor: pointer; transition: all 0.2s;
}
.preset-btn:hover { color: var(--red); border-color: var(--red-deep); }
.preset-btn.active { background: var(--red); color: var(--bg); border-color: var(--red); }

.sliders {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 10px 16px;
  align-items: center;
}
.sliders label {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--mono); font-size: 10.5px; color: var(--ink-faint);
  letter-spacing: 0.1em; text-transform: uppercase;
}
.sliders label sub {
  font-size: 8px; vertical-align: baseline; color: var(--ink-dim); margin-left: -2px;
}
.sliders input[type="range"] {
  flex: 1; -webkit-appearance: none; appearance: none;
  height: 2px; background: var(--rule); border-radius: 2px; outline: none;
}
.sliders input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 11px; height: 11px; background: var(--red); border-radius: 50%; cursor: pointer;
}
.sliders input[type="range"]::-moz-range-thumb {
  width: 11px; height: 11px; background: var(--red); border-radius: 50%; cursor: pointer; border: none;
}
.sliders .v { color: var(--ink); min-width: 44px; text-align: right; font-size: 10.5px; }
.sliders button {
  background: transparent; border: 1px solid var(--rule); color: var(--ink-dim);
  padding: 8px 14px; border-radius: 4px;
  font-family: var(--mono); font-size: 10px; letter-spacing: 0.12em; text-transform: uppercase;
  cursor: pointer; transition: all 0.2s;
  grid-column: 1 / -1; justify-self: start;
}
.sliders button:hover { color: var(--red); border-color: var(--red-deep); }

footer {
  max-width: 1080px; margin: 24px auto 0; padding: 24px 32px 40px;
  border-top: 1px solid var(--rule);
  display: flex; justify-content: space-between;
  font-family: var(--mono); font-size: 10px; color: var(--ink-faint);
  letter-spacing: 0.08em; text-transform: uppercase;
}
footer a { color: var(--ink-faint); text-decoration: none; }
footer a:hover { color: var(--red); }

@media (max-width: 700px) {
  #scope { height: 52vh; min-height: 300px; }
  .controls { margin: 0 16px 24px; padding: 12px; }
  .sliders { grid-template-columns: 1fr; }
  .sliders label { font-size: 9.5px; }
}