:root {
  --ink: #111;
  --muted: #737373;
  --line: #e7e7e7;
  --soft: #f7f7f7;
  --accept: #1a7f37;
  --reject: #c0392b;
  --warn: #9a6700;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  background: #fff;
  color: var(--ink);
  font-family: var(--sans);
}

body {
  display: grid;
  grid-template-rows: auto 1fr auto auto;
  min-height: 100vh;
}

.top {
  display: flex;
  align-items: center;
  gap: 20px 28px;
  flex-wrap: wrap;
  padding: 14px 24px;
  border-bottom: 1px solid var(--line);
}

.brand { min-width: 140px; }

.brand h1 {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
}

.brand p {
  margin: 2px 0 0;
  color: var(--muted);
  font-size: 0.8rem;
}

.kinds {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  flex: 1;
}

.kinds button,
.command-row button,
.ghost,
.run {
  appearance: none;
  border: 1px solid transparent;
  background: transparent;
  color: var(--ink);
  padding: 6px 10px;
  border-radius: 6px;
  font: 500 0.85rem/1 var(--sans);
  cursor: pointer;
  white-space: nowrap;
}

.kinds button:hover,
.command-row button:hover,
.ghost:hover {
  background: var(--soft);
}

.kinds button[aria-pressed="true"],
.command-row button[aria-pressed="true"] {
  background: #111;
  color: #fff;
}

.ghost { border-color: var(--line); }

.run {
  background: #111;
  color: #fff;
  padding: 8px 16px;
}

.run:disabled { opacity: 0.4; cursor: wait; }

.bench {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(320px, 0.85fr);
  min-height: 0;
}

.paper, .board {
  height: min(70vh, 680px);
  min-height: 0;
}

.paper {
  display: flex;
  flex-direction: column;
  min-width: 0;
  border-right: 1px solid var(--line);
}

.toolbar {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
}

.toolbar-actions {
  display: flex;
  align-items: end;
  gap: 8px;
}

.file-name input {
  width: 9.5rem;
  min-width: 0;
}

.label {
  color: var(--muted);
  font-size: 0.8rem;
  padding-bottom: 8px;
}

.field {
  display: grid;
  gap: 4px;
  font-size: 0.72rem;
  color: var(--muted);
}

.field.compact { min-width: 88px; }

select,
input[type="text"],
input[type="number"],
textarea {
  font: 14px/1.5 var(--mono);
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 6px 8px;
}

select,
input[type="text"],
input[type="number"] { min-width: 180px; }

.editor {
  display: grid;
  grid-template-columns: 40px 1fr;
  flex: 1;
  min-height: 240px;
}

.editor.short { min-height: 140px; flex: 0 0 160px; }

.gutter {
  margin: 0;
  padding: 12px 8px;
  text-align: right;
  color: #b4b4b4;
  font: 13px/24px var(--mono);
  user-select: none;
  overflow: hidden;
  border-right: 1px solid var(--line);
}

#source, #compareSource {
  width: 100%;
  height: 100%;
  border: 0;
  border-radius: 0;
  resize: none;
  background: transparent;
  padding: 12px 14px 12px 10px;
  outline: none;
  line-height: 24px;
  tab-size: 2;
}

.compare-wrap {
  border-top: 1px solid var(--line);
  background: var(--soft);
}

.board {
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 16px;
}

.command-row {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 12px;
}

.args {
  display: grid;
  gap: 10px;
  margin-bottom: 12px;
}

.args input,
.args textarea,
.args select {
  width: 100%;
  min-width: 0;
}

.args textarea { min-height: 72px; }

.run-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.preview {
  color: var(--muted);
  font-size: 0.78rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.result {
  flex: 1;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 14px;
  min-height: 180px;
  background: #fff;
}

.placeholder { color: var(--muted); margin: 0 0 10px; }

.banner {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  margin-bottom: 10px;
}

.banner.accept { color: var(--accept); }
.banner.reject,
.banner.error { color: var(--reject); }
.banner.warn { color: var(--warn); }

.words {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.words span {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 2px 8px;
  font: 13px var(--mono);
}

.words .eps { color: var(--muted); }

.graph { overflow: auto; }
.graph svg { max-width: 100%; height: auto; }

.tape {
  display: grid;
  gap: 10px;
  font-family: var(--mono);
}

.tape-row { display: grid; gap: 4px; }
.tape-cells { display: flex; flex-wrap: wrap; gap: 2px; }

.cell {
  min-width: 28px;
  height: 32px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: #fff;
}

.cell.head { border-color: #111; font-weight: 600; }
.tape-meta { color: var(--muted); font-size: 0.8rem; }

.out, .err {
  white-space: pre-wrap;
  font: 13px/1.5 var(--mono);
  margin: 0;
}

.err { color: var(--reject); margin-top: 10px; }

.help {
  padding: 16px 24px 12px;
  border-top: 1px solid var(--line);
}

.credit {
  padding: 0 24px 20px;
  color: var(--muted);
  font-size: 0.8rem;
}

.credit a {
  color: inherit;
}

.help h2 {
  margin: 0 0 8px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

.help-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 6px 28px;
  color: #333;
  font-size: 0.92rem;
}

.help-grid p { margin: 0; }

.help code {
  font-family: var(--mono);
  font-size: 0.88em;
}

dialog {
  width: min(760px, 92vw);
  max-height: 86vh;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  color: var(--ink);
  padding: 0;
}

dialog::backdrop { background: rgba(0, 0, 0, 0.2); }

.guide-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
}

.guide-head h2 {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
}

#guideText {
  padding: 8px 22px 28px;
  max-height: calc(86vh - 52px);
  overflow: auto;
  line-height: 1.55;
  font-size: 0.95rem;
}

#guideText h1 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 12px 0;
}

#guideText h2 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 28px 0 8px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

#guideText h2:first-of-type {
  margin-top: 18px;
  padding-top: 0;
  border-top: 0;
}

#guideText h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin: 18px 0 6px;
}

#guideText h4 {
  font-size: 0.88rem;
  font-weight: 600;
  margin: 14px 0 6px;
}

#guideText p { margin: 0 0 10px; }

#guideText ul,
#guideText ol {
  margin: 0 0 12px;
  padding-left: 1.25rem;
}

#guideText li { margin: 3px 0; }

#guideText a {
  color: inherit;
  text-underline-offset: 2px;
}

#guideText code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--soft);
  padding: 1px 4px;
  border-radius: 4px;
}

#guideText pre {
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 14px;
  overflow: auto;
  margin: 0 0 14px;
}

#guideText pre code {
  background: none;
  padding: 0;
  font-size: 12.5px;
  line-height: 1.5;
  white-space: pre;
}

@media (max-width: 860px) {
  .brand { order: 1; min-width: 0; }
  .top > .ghost { order: 2; margin-left: auto; }
  .kinds { order: 3; flex: 1 1 100%; }
  .bench { display: flex; flex-direction: column; }
  .paper { border-right: 0; border-bottom: 1px solid var(--line); }
  .paper, .board { height: auto; min-height: 360px; }
  select, input[type="text"], input[type="number"] { min-width: 0; }
  .toolbar { align-items: stretch; flex-wrap: wrap; }
  .field { flex: 1; }
}