:root {
  color-scheme: dark;
  --bg: #0f1319;
  --panel: #171d26;
  --border: #232c38;
  --text: #e6ecf3;
  --muted: #93a1b3;
  --accent: #4f9cf9;
  --accent-2: #3b82f6;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

header {
  padding: 28px 24px 8px;
  text-align: center;
}

header h1 {
  margin: 0 0 6px;
  font-size: 1.6rem;
}

header p {
  margin: 0;
  color: var(--muted);
}

main {
  display: grid;
  grid-template-columns: minmax(320px, 420px) 1fr;
  gap: 20px;
  padding: 20px 24px 40px;
  max-width: 1200px;
  margin: 0 auto;
}

@media (max-width: 900px) {
  main {
    grid-template-columns: 1fr;
  }
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px;
}

#dropzone {
  border: 2px dashed var(--border);
  border-radius: 12px;
  padding: 22px;
  text-align: center;
  transition: border-color 0.15s, background 0.15s;
  margin-bottom: 16px;
}

#dropzone.dragover {
  border-color: var(--accent);
  background: rgba(79, 156, 249, 0.08);
}

#dropzone p {
  margin: 0;
  color: var(--muted);
}

#source-preview {
  margin-top: 14px;
  max-width: 100%;
  max-height: 220px;
  border-radius: 8px;
  display: block;
  margin-left: auto;
  margin-right: auto;
}

button {
  font: inherit;
  cursor: pointer;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #1f2937;
  color: var(--text);
  padding: 8px 14px;
}

button:hover:not(:disabled) {
  border-color: var(--accent);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

#generate {
  background: var(--accent-2);
  border-color: var(--accent-2);
  font-weight: 600;
  padding: 11px;
}

form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

fieldset {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

legend {
  padding: 0 6px;
  color: var(--text);
  font-size: 0.82rem;
  font-weight: 600;
}

.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

label {
  display: flex;
  flex-direction: column;
  gap: 5px;
  font-size: 0.85rem;
  color: var(--muted);
}

label.checkbox {
  flex-direction: row;
  align-items: center;
  grid-column: 1 / -1;
}

input[type="number"],
select {
  font: inherit;
  background: #0f1319;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  padding: 8px 10px;
}

select {
  cursor: pointer;
}

[data-only] {
  display: none;
}

[data-only].visible {
  display: flex;
}

.hidden {
  display: none !important;
}

input[type="checkbox"] {
  width: 16px;
  height: 16px;
}

#status {
  min-height: 22px;
  margin: 16px 0 8px;
  color: var(--muted);
  font-size: 0.9rem;
}

#status.error {
  color: #f87171;
}

#download {
  display: inline-block;
  background: #16351f;
  border: 1px solid #2c6e42;
  color: #a7f3c9;
  text-decoration: none;
  padding: 10px 16px;
  border-radius: 8px;
  font-weight: 600;
}

#model-info {
  color: var(--muted);
  font-size: 0.82rem;
}

.viewer {
  display: flex;
  flex-direction: column;
  min-height: 420px;
}

.viewer-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
  font-size: 0.85rem;
}

.switch {
  flex-direction: row;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
}

#backlight-note {
  color: var(--muted);
  font-size: 0.78rem;
}

body.backlit #canvas-wrap {
  box-shadow: 0 0 60px rgba(255, 244, 214, 0.25) inset;
}

#canvas-wrap {
  flex: 1;
  border-radius: 10px;
  overflow: hidden;
  background: #0b0e13;
  min-height: 380px;
}

#canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.hint {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.8rem;
  text-align: center;
}