:root {
  --bg: #17181c;
  --panel: #1e2025;
  --panel-border: #2b2e35;
  --text: #e8e6e1;
  --text-dim: #9a9ba3;
  --accent: #6fae8f;
  --accent-soft: #3d5c4d;
  font-family: -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

.topbar {
  padding: 28px 32px 20px;
  border-bottom: 1px solid var(--panel-border);
  position: relative;
}

.lang-btn {
  position: absolute;
  top: 28px;
  right: 32px;
  background: transparent;
  border: 1px solid var(--panel-border);
  color: var(--text-dim);
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  transition: all 0.2s;
}

.lang-btn:hover {
  color: var(--text);
  border-color: var(--text-dim);
}

.topbar h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.subtitle {
  margin: 6px 0 0;
  color: var(--text-dim);
  font-size: 13px;
}

.layout {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 24px;
  padding: 24px 32px 48px;
  align-items: start;
}

.controls {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 10px;
  padding: 20px;
  position: sticky;
  top: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.control-block label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 13px;
  margin-bottom: 6px;
}

.control-name { color: var(--text); font-weight: 500; }
.control-val { color: var(--accent); font-variant-numeric: tabular-nums; }

.hint {
  margin: 6px 0 0;
  font-size: 11.5px;
  color: var(--text-dim);
  line-height: 1.4;
}

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

.file-label {
  display: flex !important;
  justify-content: center !important;
  background: var(--accent-soft);
  border: 1px dashed var(--accent);
  border-radius: 8px;
  padding: 12px;
  cursor: pointer;
  font-size: 13px;
  transition: background 0.15s;
}
.file-label:hover { background: #48684f; }
.file-label input { display: none; }

.run-btn, .download-btn {
  border: none;
  border-radius: 8px;
  padding: 11px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.1s;
}

.run-btn {
  background: var(--accent);
  color: #10231a;
}

.download-btn {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
}

.run-btn:disabled, .download-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.run-btn:not(:disabled):active, .download-btn:not(:disabled):active {
  transform: scale(0.98);
}

.status {
  margin: 0;
  font-size: 12.5px;
  color: var(--text-dim);
  min-height: 32px;
  line-height: 1.4;
}

.stage-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

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

.stage-card h2 {
  margin: 0 0 12px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.canvas-wrap {
  background:
    linear-gradient(45deg, #26282e 25%, transparent 25%),
    linear-gradient(-45deg, #26282e 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #26282e 75%),
    linear-gradient(-45deg, transparent 75%, #26282e 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
  background-color: #1a1b1f;
  border-radius: 6px;
  min-height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.canvas-wrap canvas, .canvas-wrap svg {
  max-width: 100%;
  max-height: 480px;
  display: block;
}

.svg-wrap { padding: 0; }

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .controls { position: static; }
  .stage-grid { grid-template-columns: 1fr; }
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
}
.checkbox-label input[type="checkbox"] {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}