*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:       #1e1e1e;
  --bg2:      #252526;
  --border:   #3c3c3c;
  --text:     #d4d4d4;
  --accent:   #0078d4;
  --error:    #f44747;
  --hdr-h:    40px;
  --foot-h:   120px;
}

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  display: grid;
  grid-template-rows: var(--hdr-h) 1fr var(--foot-h);
  overflow: hidden;
}

/* ── Header ─────────────────────────────────────────────────────────────── */

header {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0 12px;
}

.app-title {
  font-weight: 600;
  margin-right: 8px;
  letter-spacing: 0.02em;
}

button {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 4px 14px;
  border-radius: 3px;
  cursor: pointer;
  font-size: 13px;
  line-height: 1.6;
}

button:hover { filter: brightness(1.15); }
button:active { filter: brightness(0.9); }

/* ── Main split ─────────────────────────────────────────────────────────── */

main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr;
  overflow: hidden;
}

/* ── Editor pane ────────────────────────────────────────────────────────── */

#editor-pane {
  border-right: 1px solid var(--border);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.cm-editor {
  flex: 1;
  min-height: 0;
  font-size: 14px;
  overflow: auto;
}

.cm-editor.cm-focused { outline: none; }

/* ── View pane ──────────────────────────────────────────────────────────── */

#view-pane {
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#view-tabs {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-shrink: 0;
}

.tab {
  background: transparent;
  color: var(--text);
  border: none;
  border-bottom: 2px solid transparent;
  padding: 6px 18px;
  cursor: pointer;
  font-size: 13px;
  border-radius: 0;
}

.tab.active {
  border-bottom-color: var(--accent);
  color: #fff;
}

.tab:hover { background: rgba(255,255,255,0.05); filter: none; }

#canvas-area {
  flex: 1;
  position: relative;
  background: #000;
  overflow: hidden;
}

#preview-canvas,
#mesh-canvas {
  width: 100%;
  height: 100%;
  display: block;
  cursor: grab;
}

#preview-canvas:active { cursor: grabbing; }

/* ── Footer / log ───────────────────────────────────────────────────────── */

footer {
  background: var(--bg2);
  border-top: 1px solid var(--border);
  padding: 6px 12px;
  overflow: auto;
}

#log {
  font-family: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
  font-size: 12px;
  white-space: pre-wrap;
  color: var(--text);
}

#log.error { color: var(--error); }