:root {
  color-scheme: light;
  --bg: #f3f4f6;
  --panel: #ffffff;
  --text: #1d2026;
  --muted: #646b78;
  --border: #dcdfe5;
  --accent: #1f6feb;
  --accent-text: #ffffff;
  --hover: #eceef2;
  --editor-bg: #fbfbfc;
  --warn: #9a6700;
  --warn-bg: #fff8e1;
}
@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #0f1115;
    --panel: #171a20;
    --text: #e4e6ea;
    --muted: #9aa1ad;
    --border: #2c313a;
    --accent: #4c8dff;
    --accent-text: #0b0d10;
    --hover: #232831;
    --editor-bg: #13161b;
    --warn: #e3b341;
    --warn-bg: #2a2416;
  }
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 14px/1.4 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  display: flex;
  flex-direction: column;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}
.brand { display: flex; align-items: baseline; gap: 14px; min-width: 0; }
.logo { font: italic 600 20px/1 Georgia, "Times New Roman", serif; letter-spacing: .2px; }
.logo span { color: var(--accent); font-style: normal; }
.tagline { color: var(--muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.topbar nav a { color: var(--muted); text-decoration: none; }
.topbar nav a:hover { color: var(--text); }

.workspace {
  flex: 1;
  min-height: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 12px;
  padding: 12px;
}
.pane {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
}

.toolbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
}
.pane-title { font-weight: 600; margin-right: 4px; }
.spacer { flex: 1; }

.btn, select, .tabs button {
  font: inherit;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 5px 10px;
  cursor: pointer;
  position: relative;
  max-width: 100%;
}
.btn:hover, select:hover, .tabs button:hover { background: var(--hover); }
.btn.ghost { border-color: transparent; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-text); font-weight: 600; }
.btn.primary:hover { filter: brightness(1.08); background: var(--accent); }
.btn input[type=file] { position: absolute; inset: 0; opacity: 0; cursor: pointer; width: 100%; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

.tabs { display: inline-flex; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; }
.tabs button { border: 0; border-radius: 0; }
.tabs button[aria-selected=true] { background: var(--hover); font-weight: 600; }

.files { display: flex; flex-wrap: wrap; gap: 6px; padding: 6px 10px; border-bottom: 1px solid var(--border); }
.chip {
  display: inline-flex; align-items: center; gap: 4px;
  font-size: 12px; padding: 2px 4px 2px 8px;
  border: 1px solid var(--border); border-radius: 999px; color: var(--muted);
}
.chip.main { color: var(--text); font-weight: 600; }
.chip button { border: 0; background: none; color: inherit; cursor: pointer; padding: 0 4px; font-size: 14px; line-height: 1; }

.editor-wrap { position: relative; flex: 1; min-height: 0; }
#source {
  width: 100%;
  height: 100%;
  resize: none;
  border: 0;
  outline: none;
  padding: 12px 14px;
  background: var(--editor-bg);
  color: var(--text);
  font: 13px/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  tab-size: 2;
}
.drop-overlay {
  position: absolute; inset: 8px;
  display: none; place-items: center;
  border: 2px dashed var(--accent); border-radius: 8px;
  background: color-mix(in srgb, var(--panel) 85%, transparent);
  color: var(--accent); font-weight: 600; font-size: 16px;
  pointer-events: none;
}
.source-pane.dragging .drop-overlay { display: grid; }

.output-body { position: relative; flex: 1; min-height: 0; }
#preview { width: 100%; height: 100%; border: 0; display: block; background: #fff; }
@media (prefers-color-scheme: dark) { #preview { background: #15171b; } }
#code {
  margin: 0; height: 100%; overflow: auto; padding: 12px 14px;
  background: var(--editor-bg);
  font: 12px/1.5 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  white-space: pre-wrap; word-break: break-word;
}

.status {
  display: flex; flex-wrap: wrap; align-items: flex-start; gap: 4px 12px;
  padding: 6px 10px; border-top: 1px solid var(--border);
  color: var(--muted); font-size: 12px;
}
#warnings { color: var(--warn); }
#warnings summary { cursor: pointer; }
#warnings ul {
  margin: 6px 0 2px; padding: 6px 10px 6px 24px;
  max-height: 140px; overflow: auto;
  background: var(--warn-bg); border-radius: 6px;
}
#warnings li { margin: 2px 0; }

@media (max-width: 860px) {
  body { height: auto; }
  .workspace { grid-template-columns: minmax(0, 1fr); padding: 8px; }
  .pane { min-height: 70vh; }
  .tagline { display: none; }
}