:root {
  --bg: #0d1117;
  --panel: #161b22;
  --panel-2: #11161d;
  --border: #2d333b;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #6cb6ff;
  --green: #3fb950;
  --green-bg: #12261a;
  --red: #f85149;
  --red-bg: #2a1416;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  height: 100%;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.1rem 1.5rem 0.9rem;
  border-bottom: 1px solid var(--border);
}

.title h1 {
  margin: 0;
  font-size: 1.35rem;
  letter-spacing: -0.01em;
}

.title h1 .dot {
  color: var(--accent);
}

.tagline {
  margin: 0.3rem 0 0;
  color: var(--muted);
  font-size: 0.86rem;
  max-width: 60ch;
}

.links {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.85rem;
}

.links a {
  color: var(--accent);
  text-decoration: none;
}

.links a:hover {
  text-decoration: underline;
}

.version {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.78rem;
}

.grid {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 1px;
  background: var(--border);
  min-height: 0;
}

@media (max-width: 1000px) {
  .grid {
    grid-template-columns: 1fr;
  }
}

.pane {
  background: var(--panel);
  display: flex;
  flex-direction: column;
  min-height: 320px;
  min-width: 0;
}

.pane h2 {
  margin: 0;
  padding: 0.6rem 0.9rem;
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
}

.pane h2 .sub {
  text-transform: none;
  letter-spacing: 0;
  font-weight: 400;
  color: #6e7681;
}

.editor {
  flex: 1;
  display: flex;
  min-height: 0;
  background: var(--panel-2);
}

/* The gutter must share the textarea's exact font metrics and vertical padding
   so line numbers line up with their lines. Scroll is synced from JS. */
.gutter {
  flex: 0 0 auto;
  padding: 0.9rem 0.5rem 0.9rem 0.7rem;
  overflow: hidden;
  text-align: right;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.55;
  color: #5a626c;
  user-select: none;
  border-right: 1px solid var(--border);
  background: var(--panel-2);
}

.gutter .ln {
  white-space: pre;
}

.gutter .ln.err {
  color: var(--red);
  font-weight: 600;
  cursor: pointer;
}

.gutter .ln.err::after {
  content: "●";
  font-size: 0.6em;
  vertical-align: middle;
  margin-left: 0.25rem;
}

#source {
  flex: 1;
  resize: none;
  border: 0;
  outline: none;
  padding: 0.9rem 0.9rem 0.9rem 0.6rem;
  background: var(--panel-2);
  color: var(--text);
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.55;
  tab-size: 2;
}

.code-out,
.diff-out {
  flex: 1;
  margin: 0;
  padding: 0.9rem;
  overflow: auto;
  background: var(--panel-2);
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.55;
  white-space: pre;
}

.code-out code {
  font-family: inherit;
}

.diagnostics {
  border-top: 1px solid var(--border);
  max-height: 38%;
  overflow: auto;
  font-family: var(--mono);
  font-size: 12px;
}

.diag {
  padding: 0.4rem 0.9rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 0.5rem;
  align-items: baseline;
  cursor: pointer;
}

.diag:hover {
  background: var(--red-bg);
}

.diag:focus-visible {
  outline: none;
  background: var(--red-bg);
  box-shadow: inset 2px 0 0 var(--red);
}

.diag .loc {
  text-decoration: underline dotted;
  text-underline-offset: 2px;
}

.diag .code {
  color: var(--red);
  font-weight: 600;
}

.diag .loc {
  color: var(--muted);
}

.diag .msg {
  white-space: pre-wrap;
}

.diag-ok {
  padding: 0.5rem 0.9rem;
  color: var(--green);
  font-family: var(--mono);
  font-size: 12px;
}

.diff-caption,
.diff-note {
  margin: 0;
  padding: 0.6rem 0.9rem;
  color: var(--muted);
  font-size: 0.8rem;
}

.diff-note {
  border-top: 1px solid var(--border);
  color: var(--text);
}

.diff-note strong {
  color: var(--green);
}

.diff-line {
  display: block;
}

.diff-add {
  background: var(--green-bg);
  color: var(--green);
}

.diff-del {
  background: var(--red-bg);
  color: var(--red);
}

.diff-same {
  color: var(--muted);
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 0.7rem 1.5rem;
  color: var(--muted);
  font-size: 0.78rem;
}

.site-footer code {
  font-family: var(--mono);
  color: var(--text);
}

[aria-busy="true"] {
  opacity: 0.6;
}