:root {
  color-scheme: dark;
  --bg: #101114;
  --panel: #101114;
  --border: #33363d;
  --border-dim: #24262c;
  --text: #d4d4d4;
  --dim: #6f7581;
  --dimmer: #4b4f58;
  --accent: #5c9dff;
  --error: #ff6b6b;
  --ok: #7CFC9C;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, 'Liberation Mono', monospace;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
}

button, input, select {
  font-family: inherit;
}

#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

/* --- text-based rules, used instead of border lines --- */

.hrule {
  overflow: hidden;
  white-space: pre;
  line-height: 1;
  height: 1em;
  color: var(--border-dim);
  font-size: 13px;
  user-select: none;
}

.hrule::before {
  content: "────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────";
}

/* --- toolbar --- */

#toolbar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 14px;
  background: var(--panel);
  flex-wrap: wrap;
}

#logo {
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--dim);
  margin-right: 2px;
  font-size: 13px;
  text-decoration: none;
}

#logo:visited {
  color: var(--dim);
}

#logo:hover {
  color: var(--text);
}

.cursor {
  color: var(--accent);
  animation: blink 1s step-start infinite;
}

@keyframes blink {
  0%, 49% { opacity: 1; }
  50%, 100% { opacity: 0; }
}

.tsep {
  color: var(--border-dim);
  width: 1px;
  align-self: stretch;
  background: var(--border-dim);
  margin: 2px 0;
}

.field {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--dim);
}

.field-label {
  color: var(--dim);
}

.field-x {
  color: var(--dimmer);
}

.field input {
  width: 4.5ch;
  background: transparent;
  color: var(--text);
  border: none;
  border-bottom: 1px solid transparent;
  padding: 1px 2px;
  font-size: 13px;
  text-align: right;
}

.field input:hover {
  border-bottom-color: var(--border);
}

.field input:focus {
  outline: none;
  border-bottom-color: var(--accent);
}

.select-wrap {
  position: relative;
  display: inline-flex;
  align-items: center;
}

.select-wrap::after {
  content: "▼";
  position: absolute;
  right: 2px;
  font-size: 8px;
  color: var(--dimmer);
  pointer-events: none;
}

.select-wrap select {
  appearance: none;
  -webkit-appearance: none;
  background: transparent;
  color: var(--text);
  border: none;
  border-bottom: 1px solid transparent;
  padding: 1px 16px 1px 2px;
  font-size: 13px;
}

.select-wrap select:hover {
  border-bottom-color: var(--border);
}

.select-wrap select:focus {
  outline: none;
  border-bottom-color: var(--accent);
}

.actions, .view-actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

.action {
  background: none;
  color: var(--text);
  border: none;
  padding: 3px 6px;
  font-size: 13px;
  cursor: pointer;
}

.action:hover {
  color: var(--accent);
  text-decoration: underline;
}

.action-run {
  color: var(--ok);
}

.action-stop {
  color: var(--error);
}

.action-quiet {
  color: var(--dimmer);
  font-size: 12px;
}

.action-quiet:hover {
  color: var(--dim);
  text-decoration: underline;
}

#status {
  margin-left: auto;
  font-size: 12px;
  color: var(--dimmer);
}

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

#status.running {
  color: var(--ok);
}

/* --- panels: preview is the hero, editor secondary --- */

#panels {
  flex: 1;
  display: flex;
  min-height: 0;
}

#editor-panel, #preview-panel {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
}

.panel-head {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 10px;
  flex: 0 0 auto;
}

.panel-rule {
  flex: 1;
  overflow: hidden;
  white-space: pre;
  line-height: 1;
  color: var(--border-dim);
}

.panel-rule::before {
  content: "────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────";
}

#editor-panel {
  flex: 4;
  border-right: 1px solid var(--border-dim);
}

#editor-panel .panel-title {
  font-size: 11px;
  color: var(--dimmer);
  letter-spacing: 0.04em;
}

#editor-panel .panel-rule {
  color: var(--border-dim);
}

#preview-panel {
  flex: 5;
}

#preview-panel .panel-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.04em;
}

#preview-panel .panel-rule {
  color: var(--border);
}

#editor-panel .CodeMirror {
  flex: 1;
  height: 100%;
  font-family: var(--mono);
  font-size: 13px;
}

#preview {
  flex: 1;
  border: none;
  background: #1e1e1e;
}

/* --- status / log, least visual weight --- */

#log-bar {
  padding: 3px 14px;
  background: var(--panel);
  font-size: 12px;
  color: var(--dimmer);
  min-height: 16px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

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

/* Explicit layout toggle (id+class beats the plain #panels/#editor-panel
   selectors in the media query below, so an explicit choice always wins
   regardless of viewport width). With neither class set, the media query
   still auto-stacks on narrow screens. */
#panels.layout-row {
  flex-direction: row;
}
#panels.layout-row #editor-panel, #panels.layout-row #preview-panel {
  width: auto;
  height: auto;
}
#panels.layout-row #editor-panel {
  border-right: 1px solid var(--border-dim);
  border-bottom: none;
}

#panels.layout-column {
  flex-direction: column;
}
#panels.layout-column #editor-panel, #panels.layout-column #preview-panel {
  width: 100%;
  height: auto;
}
#panels.layout-column #editor-panel {
  border-right: none;
  border-bottom: 1px solid var(--border-dim);
}

#preview-panel:fullscreen {
  width: 100%;
  height: 100%;
  background: #1e1e1e;
}

#preview-panel:fullscreen .panel-head {
  display: none;
}

#preview-panel:fullscreen #preview {
  width: 100%;
  height: 100%;
}

/* --- help dialog --- */

#help-dialog {
  width: min(560px, 90vw);
  max-height: 80vh;
  padding: 0;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
}

#help-dialog::backdrop {
  background: rgba(0, 0, 0, 0.6);
}

.help-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 14px;
  border-bottom: 1px solid var(--border-dim);
}

.help-title {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text);
}

.help-body {
  padding: 4px 16px 16px;
  overflow-y: auto;
  max-height: calc(80vh - 41px);
  font-size: 13px;
  line-height: 1.5;
}

.help-body h3 {
  margin: 18px 0 6px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--dim);
}

.help-body h3:first-child {
  margin-top: 8px;
}

.help-body p {
  margin: 6px 0;
  color: var(--text);
}

.help-body code {
  font-family: var(--mono);
  color: var(--accent);
}

.help-body kbd {
  font-family: var(--mono);
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  border-radius: 3px;
  padding: 0 4px;
  font-size: 11px;
  color: var(--text);
}

.help-body pre {
  margin: 6px 0;
  padding: 8px 10px;
  background: var(--panel);
  border: 1px solid var(--border-dim);
  overflow-x: auto;
  font-size: 12px;
  color: var(--text);
}

.help-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 6px 0;
}

.help-body table td {
  padding: 4px 0;
  vertical-align: top;
  border-bottom: 1px solid var(--border-dim);
}

.help-body table td:first-child {
  white-space: nowrap;
  padding-right: 14px;
  color: var(--dim);
}

@media (max-width: 800px) {
  #panels {
    flex-direction: column;
  }
  #editor-panel, #preview-panel {
    width: 100%;
  }
  #editor-panel {
    border-right: none;
    border-bottom: 1px solid var(--border-dim);
    height: auto;
  }
}