:root {
  color-scheme: dark;
  --bg: #0f1115;
  --panel: #171a21;
  --border: #2a2e37;
  --text: #e6e8ec;
  --muted: #9aa1ac;
  --accent: #6ea8fe;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, "Segoe UI", "Hiragino Kaku Gothic ProN", sans-serif;
  padding: 24px;
}

.wrap { max-width: 1100px; margin: 0 auto; }

h1 { font-size: 1.5rem; margin: 0 0 4px; }
p.sub { color: var(--muted); margin: 0 0 24px; font-size: 0.9rem; }

.tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.tab-btn {
  padding: 8px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--muted);
  cursor: pointer;
  font-size: 0.9rem;
}

.tab-btn.active {
  color: var(--text);
  border-color: var(--accent);
  background: #1b2333;
}

.layout {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 20px;
}

@media (max-width: 800px) {
  .layout { grid-template-columns: 1fr; }
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.control-row {
  margin-bottom: 14px;
}

.control-row label {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 6px;
}

input[type="range"] {
  width: 100%;
}

input[type="color"] {
  width: 100%;
  height: 32px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: transparent;
  cursor: pointer;
}

select {
  width: 100%;
  padding: 6px 8px;
  background: #0f1115;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--muted);
}

.stops-list, .layers-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 10px;
}

.stop-row, .layer-row {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px;
}

.stop-row-head, .layer-row-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.small-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 6px;
  padding: 4px 10px;
  cursor: pointer;
  font-size: 0.8rem;
}

.preview-area {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.preview-box {
  height: 260px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0.85);
  font-weight: 600;
  transition: all 0.1s ease;
  background: #222834;
}

.preview-bg {
  padding: 40px;
  border-radius: 16px;
  background: linear-gradient(135deg, #1c2030, #262d40);
}

.code-panel {
  position: relative;
}

.code-toggle {
  display: flex;
  gap: 8px;
  margin-bottom: 10px;
}

pre {
  background: #0b0d11;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px;
  overflow-x: auto;
  font-size: 0.82rem;
  color: #b8f2c9;
  white-space: pre-wrap;
  word-break: break-all;
}

.copy-btn {
  position: absolute;
  top: 44px;
  right: 10px;
  background: var(--accent);
  color: #0f1115;
  border: none;
  border-radius: 6px;
  padding: 6px 12px;
  font-weight: 600;
  font-size: 0.8rem;
  cursor: pointer;
}