:root {
  color-scheme: light dark;
  --page: #f8faf7;
  --card: #fffdf9;
  --ink: #18231c;
  --ink-soft: color-mix(in oklab, var(--ink) 76%, transparent);
  --ink-faint: color-mix(in oklab, var(--ink) 56%, transparent);
  --accent: #2f7d57;
  --accent-soft: #eaf2ee;
  --rule: #e0e8df;
  --danger: #a65d57;
  --gold: #b08948;
  --font-display: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia,
    "Songti SC", "Noto Serif CJK SC", serif;
  --font-body: ui-sans-serif, -apple-system, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Code", "JetBrains Mono",
    Menlo, Consolas, monospace;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(24, 35, 28, 0.05), 0 8px 24px rgba(24, 35, 28, 0.06);
}

:root[data-theme="dark"] {
  --page: #141a17;
  --card: #1b231e;
  --ink: #e6f0e8;
  --accent: #7fc0a0;
  --accent-soft: #23342b;
  --rule: #2c3730;
  --danger: #d99089;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 8px 24px rgba(0, 0, 0, 0.3);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
}

.shell {
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px 24px 40px;
}

/* Header ------------------------------------------------------------------ */

.masthead {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--rule);
}

.masthead h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.9rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.masthead .tagline {
  flex: 1 1 320px;
  margin: 0;
  color: var(--ink-faint);
  font-size: 0.92rem;
}

.masthead .badge {
  padding: 3px 10px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.theme-toggle {
  padding: 6px 12px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: var(--card);
  color: var(--ink-soft);
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
}

.theme-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Controls ---------------------------------------------------------------- */

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 16px;
  padding: 16px 0;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.field > label {
  color: var(--ink-faint);
  font-size: 0.74rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.field input,
.field select {
  min-width: 180px;
  padding: 7px 10px;
  border: 1px solid var(--rule);
  border-radius: 8px;
  background: var(--card);
  color: var(--ink);
  font: inherit;
  font-size: 0.9rem;
}

.field input:focus,
.field select:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

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

button.action {
  padding: 7px 14px;
  border: 1px solid var(--rule);
  border-radius: 8px;
  background: var(--card);
  color: var(--ink);
  font: inherit;
  font-size: 0.86rem;
  cursor: pointer;
}

button.action:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Workspace --------------------------------------------------------------- */

.workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 20px;
}

.pane {
  display: flex;
  flex-direction: column;
  min-height: 0;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--card);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.pane > header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--rule);
  background: color-mix(in oklab, var(--accent-soft) 55%, transparent);
}

.pane > header h2 {
  margin: 0;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.pane > header .hint {
  color: var(--ink-faint);
  font-family: var(--font-mono);
  font-size: 0.74rem;
}

#editor {
  flex: 1;
  min-height: 460px;
  padding: 16px 18px;
  border: 0;
  background: var(--card);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.87rem;
  line-height: 1.7;
  tab-size: 2;
  resize: vertical;
}

#editor:focus {
  outline: none;
  box-shadow: inset 3px 0 0 var(--accent);
}

.preview-host {
  position: relative;
  flex: 1;
  min-height: 460px;
  background: #fff;
}

#preview {
  flex: 1;
  min-height: 460px;
  width: 100%;
  height: 100%;
  border: 0;
  background: #fff;
}

/* Metrics ----------------------------------------------------------------- */

.metrics {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
}

.metric {
  padding: 12px 14px;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--card);
}

.metric .label {
  color: var(--ink-faint);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.metric .value {
  font-family: var(--font-display);
  font-size: 1.7rem;
  line-height: 1.2;
}

.metric.is-pass .value {
  color: var(--accent);
}

.metric.is-fail .value {
  color: var(--danger);
}

.checks {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.check {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 12px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: var(--card);
  font-size: 0.84rem;
}

.check .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ink-faint);
}

.check.is-pass {
  border-color: color-mix(in oklab, var(--accent) 45%, var(--rule));
}

.check.is-pass .dot {
  background: var(--accent);
}

.check.is-fail .dot {
  background: var(--danger);
}

/* Status ------------------------------------------------------------------ */

.status {
  margin-top: 16px;
  padding: 12px 14px;
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  background: var(--card);
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.status.is-error {
  border-left-color: var(--danger);
  color: var(--danger);
}

.status.is-loading {
  border-left-color: var(--gold);
}

.note {
  margin-top: 22px;
  padding-top: 16px;
  border-top: 1px solid var(--rule);
  color: var(--ink-faint);
  font-size: 0.85rem;
}

.note code {
  padding: 1px 5px;
  border-radius: 4px;
  background: var(--accent-soft);
  font-family: var(--font-mono);
  font-size: 0.85em;
}

/* Responsive -------------------------------------------------------------- */

@media (max-width: 900px) {
  .workspace {
    grid-template-columns: minmax(0, 1fr);
  }

  #editor,
  #preview,
  .preview-host {
    min-height: 340px;
  }

  .masthead h1 {
    font-size: 1.5rem;
  }
}

@media (prefers-reduced-motion: no-preference) {
  button.action,
  .theme-toggle {
    transition: border-color 0.15s ease, color 0.15s ease;
  }
}