:root {
  --bg: #1e1e1e;
  --bg-panel: #252526;
  --bg-bar: #333333;
  --bg-status: #007acc;
  --border: #3c3c3c;
  --fg: #d4d4d4;
  --fg-dim: #9d9d9d;
  --accent: #0e639c;
  --accent-hover: #1177bb;
  --error: #f14c4c;
  --warning: #cca700;
  --ok: #89d185;
  --font-ui: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-ui);
  font-size: 13px;
  overflow: hidden;
}

body {
  display: flex;
  flex-direction: column;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 44px;
  padding: 0 16px;
  background: var(--bg-bar);
  border-bottom: 1px solid var(--border);
  flex: 0 0 auto;
}

.brand { display: flex; align-items: baseline; gap: 8px; }
.logo {
  font-weight: 700;
  font-size: 16px;
  padding: 2px 7px;
  border-radius: 4px;
  background: var(--accent);
  color: #fff;
}
.title { font-size: 14px; color: var(--fg-dim); }

.controls { display: flex; align-items: center; gap: 8px; }

.select-wrap { display: flex; align-items: center; gap: 6px; color: var(--fg-dim); }
select {
  background: var(--bg-panel);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 5px 8px;
  font: inherit;
}

.btn {
  background: var(--bg-panel);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 6px 14px;
  font: inherit;
  cursor: pointer;
}
.btn:hover { background: #2a2d2e; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { background: var(--accent-hover); }
.btn:disabled { opacity: .5; cursor: default; }

.workspace {
  flex: 1 1 auto;
  display: flex;
  min-height: 0;
}

.main {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  min-width: 240px;
  min-height: 0;
}

.pane { display: flex; flex-direction: column; min-height: 0; min-width: 0; }
.editor-pane { flex: 1 1 auto; min-height: 120px; }
#editor { flex: 1 1 auto; min-height: 0; }

.divider { background: var(--border); flex: 0 0 5px; }
.divider:hover, .divider.active { background: var(--accent); }
.h-divider { cursor: row-resize; }
.v-divider { cursor: col-resize; }

.output-pane { flex: 0 0 32%; background: var(--bg-panel); border-top: 1px solid var(--border); }

.guide-pane { flex: 0 0 380px; background: var(--bg-panel); border-left: 1px solid var(--border); }
.pane-header a { color: var(--fg-dim); text-decoration: none; text-transform: none; letter-spacing: 0; }
.pane-header a:hover { color: var(--fg); }

.guide {
  flex: 1 1 auto;
  overflow: auto;
  padding: 4px 16px 24px;
  line-height: 1.55;
  font-size: 13px;
}
.guide h1 { font-size: 17px; margin: 14px 0 8px; }
.guide h2 { font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--fg-dim); margin: 22px 0 6px; }
.guide p { margin: 6px 0; }
.guide ol, .guide ul { padding-left: 20px; margin: 6px 0; }
.guide li { margin: 3px 0; }
.guide code {
  font-family: var(--font-mono);
  font-size: 12px;
  background: #1e1e1e;
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0 4px;
}
.guide pre {
  position: relative;
  margin: 8px 0 12px;
  padding: 10px 12px;
  background: #1e1e1e;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: auto;
}
.guide pre code { background: none; border: 0; padding: 0; font-size: 12.5px; line-height: 1.5; white-space: pre; }
.guide pre .load {
  position: absolute;
  top: 6px;
  right: 6px;
  opacity: 0;
  padding: 2px 8px;
  font-size: 11px;
  background: var(--accent);
  color: #fff;
  border: 0;
  border-radius: 3px;
  cursor: pointer;
  transition: opacity .15s;
}
.guide pre:hover .load { opacity: 1; }
.guide pre .load:hover { background: var(--accent-hover); }

.pane-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 12px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--fg-dim);
  border-bottom: 1px solid var(--border);
  flex: 0 0 auto;
}
.status { text-transform: none; letter-spacing: 0; font-size: 12px; }
.status.ok { color: var(--ok); }
.status.err { color: var(--error); }
.status.busy { color: var(--warning); }

.stdout {
  margin: 0;
  padding: 10px 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.5;
  white-space: pre-wrap;
  word-break: break-word;
  overflow: auto;
  flex: 1 1 auto;
  min-height: 0;
}
.stdout .note { color: var(--fg-dim); font-style: italic; }
.stdout .internal { color: var(--error); }

.diagnostics {
  flex: 0 0 auto;
  max-height: 45%;
  overflow: auto;
  border-top: 1px solid var(--border);
}
.diagnostics:empty { display: none; }

.diag {
  display: grid;
  grid-template-columns: auto 1fr;
  column-gap: 10px;
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.45;
}
.diag:hover { background: #2a2d2e; }
.diag .code { color: var(--error); font-weight: 700; }
.diag .message { color: var(--fg); }
.diag .where { grid-column: 2; color: var(--fg-dim); }
.diag .label { grid-column: 2; color: var(--warning); }
.diag .notes { grid-column: 2; color: var(--fg-dim); white-space: pre-wrap; }

.statusbar {
  display: flex;
  align-items: center;
  gap: 16px;
  height: 22px;
  padding: 0 12px;
  background: var(--bg-status);
  color: #fff;
  font-size: 12px;
  flex: 0 0 auto;
}
.statusbar a { color: #fff; text-decoration: none; }
.statusbar a:hover { text-decoration: underline; }
.spacer { flex: 1 1 auto; }
.toast { opacity: 0; transition: opacity .3s; }
.toast.show { opacity: 1; }

@media (max-width: 900px) {
  .workspace { flex-direction: column; overflow: auto; }
  .main { flex: 0 0 auto; height: 70vh; }
  .v-divider { display: none; }
  .guide-pane { flex: 0 0 auto; border-left: 0; border-top: 1px solid var(--border); }
  .guide { overflow: visible; }
  .select-wrap span { display: none; }
  .title { display: none; }
}