:root {
  --bg: #0f1014;
  --panel: #181c24;
  --panel-2: #1f2530;
  --border: #2a3140;
  --fg: #e6ecf2;
  --muted: #8b95a3;
  --accent: #7cc4ff;
  --accent-dim: #4a7aa8;
  --pink: #ff7c9d;
  --green: #7cffa1;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  font-size: 14px;
  line-height: 1.5;
  min-height: 100vh;
}

code {
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
  background: var(--panel);
  padding: 1px 5px;
  border-radius: 3px;
  font-size: 0.88em;
}

a { color: var(--accent); }

header {
  max-width: 1080px;
  margin: 28px auto 16px;
  padding: 0 20px;
}

h1 {
  margin: 0 0 6px;
  font-size: 1.7rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
  max-width: 76ch;
}

main {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px 40px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 18px;
}

.panel h2 {
  margin: 0 0 10px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.07em;
}

.panel-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

/* ── Curve panel ── */

.curve-stage {
  background: #0c0e13;
  border-radius: 6px;
  padding: 10px;
}

#curveSvg {
  width: 100%;
  height: auto;
  display: block;
}

.quad-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 4px;
  margin-top: 12px;
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
  font-size: 0.92rem;
  color: var(--muted);
}

.quad-label { color: var(--accent); }

.quad-input {
  width: 70px;
  background: #0c0e13;
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 4px 8px;
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
  font-size: 0.88rem;
  outline: none;
  font-variant-numeric: tabular-nums;
}

.quad-input:focus { border-color: var(--accent); }

.css-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 10px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 8px 12px;
}

.css-out {
  flex: 1;
  background: transparent;
  color: var(--accent);
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
  font-size: 0.9rem;
  padding: 0;
  word-break: break-all;
}

.copy {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent-dim);
  border-radius: 4px;
  padding: 4px 12px;
  font-size: 0.82rem;
  cursor: pointer;
  font-family: inherit;
}

.copy:hover { border-color: var(--accent); }

/* ── Preview panel ── */

.preview-stage {
  background:
    linear-gradient(45deg, #1a1d24 25%, transparent 25%),
    linear-gradient(-45deg, #1a1d24 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #1a1d24 75%),
    linear-gradient(-45deg, transparent 75%, #1a1d24 75%);
  background-size: 14px 14px;
  background-position: 0 0, 0 7px, 7px -7px, -7px 0;
  background-color: #14171d;
  border-radius: 6px;
  padding: 24px 32px;
  min-height: 220px;
  overflow: hidden;
}

.preview-box {
  width: 56px;
  height: 56px;
  background: linear-gradient(135deg, #7cc4ff, #c084fc);
  border-radius: 12px;
  box-shadow: 0 8px 24px rgba(124, 196, 255, 0.3);
  /* animated via JS — see app.js */
}

@keyframes bezier-demo {
  0%   { transform: translateX(0); }
  100% { transform: translateX(min(280px, calc(100% - 56px))); }
}

.controls-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.control {
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex: 1;
}

.control .label {
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.07em;
}

.control input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

.control .value {
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
  font-size: 0.78rem;
  color: var(--muted);
}

.replay {
  background: var(--panel-2);
  color: var(--accent);
  border: 1px solid var(--accent-dim);
  border-radius: 4px;
  padding: 6px 14px;
  font-size: 0.85rem;
  cursor: pointer;
  font-family: inherit;
}

.replay:hover { border-color: var(--accent); }

/* ── Presets ── */

.presets {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.preset {
  background: var(--panel-2);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 4px 12px;
  font-size: 0.82rem;
  cursor: pointer;
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
}

.preset:hover { border-color: var(--accent); color: var(--accent); }

/* ── Notes ── */

.notes-panel ul {
  margin: 0;
  padding-left: 18px;
}

.notes-panel li { margin-bottom: 6px; }

footer {
  margin-top: 4px;
  color: var(--muted);
  font-size: 0.82rem;
  text-align: center;
  line-height: 1.6;
}

footer code {
  background: var(--panel-2);
  padding: 1px 5px;
  border-radius: 3px;
  font-family: "JetBrains Mono", "SF Mono", Consolas, monospace;
  font-size: 0.8rem;
}

@media (max-width: 720px) {
  .panel-row { grid-template-columns: 1fr; }
}