:root {
  --ui-bg: #c7c7c3;
  --ui-panel: #ffffff;
  --ui-border: #ddd;
  --ui-text: #222;
  --ui-muted: #666;
  --accent: #2563eb;
  --shell-max-width: 1600px;
}
* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0; height: 100%;
  background: var(--ui-bg); color: var(--ui-text);
  font-family: -apple-system, Segoe UI, Arial, sans-serif;
}
body { display: flex; flex-direction: column; height: 100vh; gap: 16px; padding: 16px 20px; }

header {
  width: 100%; max-width: var(--shell-max-width); margin: 0 auto;
  padding: 14px 20px;
  background: var(--ui-panel);
  border: 1px solid var(--ui-border);
  border-radius: 10px;
  box-shadow: 0 1px 3px rgba(0,0,0,.08);
  display: flex; flex-wrap: wrap; gap: 14px 24px;
  align-items: flex-end;
}
h1 { font-size: 15px; margin: 0 24px 0 0; font-weight: 600; align-self: center; white-space: nowrap; }

.icon-btn {
  width: 34px; height: 34px; padding: 0; font-size: 16px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 50%;
}

.ctrl-group { display: flex; flex-direction: column; gap: 4px; }
.ctrl-group label { font-size: 11px; color: var(--ui-muted); text-transform: uppercase; letter-spacing: .03em; }
.ctrl-row { display: flex; gap: 6px; align-items: center; }
select, input[type=number], input[type=text] {
  font-size: 13px; padding: 4px 6px; border: 1px solid var(--ui-border); border-radius: 4px;
  background: #fff; color: var(--ui-text);
}
input[type=number] { width: 58px; }
.custom-font-input { width: 140px; display: none; }

.actions { margin-left: auto; display: flex; gap: 8px; align-items: flex-end; flex-wrap: wrap; }
button {
  font-size: 13px; padding: 7px 12px; border: 1px solid var(--ui-border); border-radius: 5px;
  background: #fff; cursor: pointer; color: var(--ui-text);
}
button:hover { background: #f0f0f0; }
#copyStatus { font-size: 12px; color: #16a34a; align-self: center; min-width: 90px; }

main {
  flex: 1; display: flex; min-height: 0;
  width: 100%; max-width: var(--shell-max-width); margin: 0 auto;
}
.pane {
  flex: 1 1 0; min-width: 0; display: flex; flex-direction: column;
  background: var(--ui-panel); border: 1px solid var(--ui-border);
  border-radius: 10px; box-shadow: 0 1px 3px rgba(0,0,0,.08); overflow: hidden;
}
.resizer {
  flex: 0 0 20px; display: flex; align-items: center; justify-content: center;
  cursor: col-resize; touch-action: none;
}
.resizer::after {
  content: ""; width: 4px; height: 44px; border-radius: 2px;
  background: var(--ui-border);
}
.resizer:hover::after, .resizer.dragging::after { background: var(--accent); }
.pane-label {
  font-size: 11px; color: var(--ui-muted); text-transform: uppercase; letter-spacing: .03em;
  padding: 6px 14px; background: var(--ui-panel); border-bottom: 1px solid var(--ui-border);
}
.pane-label-row { display: flex; align-items: center; justify-content: space-between; padding-right: 8px; }
.pane-label-row .icon-btn {
  width: 24px; height: 24px; font-size: 13px; color: var(--ui-muted);
}
.pane-label-row .icon-btn:hover { background: #f0f0f0; color: var(--ui-text); }
#mdInput {
  flex: 1; border: none; outline: none; resize: none; padding: 16px;
  font-family: Consolas, Menlo, monospace; font-size: 13.5px; line-height: 1.5;
  background: #fff;
}
#previewWrap { flex: 1; overflow: auto; background: #fff; padding: 24px 32px; }

/* Rendered content styles, driven by CSS variables.
   --x-fg/--x-bg are only set when a category's color is NOT "Automatic";
   otherwise they're left unset so the var() fallback (inherit/transparent) applies. */
.preview-content {
  font-family: var(--body-font);
  font-size: var(--body-size);
  line-height: 1.55;
  color: var(--body-fg, inherit);
  background: var(--body-bg, transparent);
  max-width: 720px;
}
.preview-content h1, .preview-content h2, .preview-content h3,
.preview-content h4, .preview-content h5, .preview-content h6 {
  font-family: var(--heading-font);
  font-weight: 700;
  margin: 1.2em 0 .5em;
  line-height: 1.25;
  color: var(--heading-fg, inherit);
  background: var(--heading-bg, transparent);
}
.preview-content h1 { font-size: var(--heading-size); }
.preview-content h2 { font-size: calc(var(--heading-size) * 0.83); }
.preview-content h3 { font-size: calc(var(--heading-size) * 0.70); }
.preview-content h4 { font-size: calc(var(--heading-size) * 0.60); }
.preview-content h5 { font-size: calc(var(--heading-size) * 0.53); }
.preview-content h6 { font-size: calc(var(--heading-size) * 0.48); }
.preview-content p, .preview-content li, .preview-content blockquote { margin: .6em 0; }
.preview-content ul, .preview-content ol { padding-left: 1.4em; }
.preview-content blockquote {
  border-left: 3px solid #ccc; margin-left: 0; padding-left: 1em; color: #555;
}
.preview-content a { color: var(--accent); }
.preview-content img { max-width: 100%; }
.preview-content hr { border: none; border-top: 1px solid #ccc; margin: 2em 0; }
.preview-content code, .preview-content pre, .preview-content pre code {
  font-family: var(--mono-font);
  font-size: var(--mono-size);
  color: var(--mono-fg, inherit);
}
.preview-content code {
  background: var(--mono-bg, transparent); padding: .15em .35em; border-radius: 3px;
  border: 1px solid rgba(127,127,127,.25);
}
.preview-content pre {
  background: var(--mono-bg, transparent); padding: 12px 14px; border-radius: 6px; overflow-x: auto;
  line-height: 1.45; border: 1px solid rgba(127,127,127,.25);
}
.preview-content pre code { background: none; padding: 0; border: none; }
.preview-content table { border-collapse: collapse; margin: 1em 0; }
.preview-content th, .preview-content td { border: 1px solid #ccc; padding: 6px 10px; }
.preview-content th { background: #f5f5f5; }

footer {
  width: 100%; max-width: var(--shell-max-width); margin: 0 auto;
  padding: 8px 20px; font-size: 11px; color: var(--ui-muted);
  background: var(--ui-panel); border: 1px solid var(--ui-border); border-radius: 10px;
}

@media (max-width: 800px) {
  main { flex-direction: column; }
  .resizer { display: none; }
  .pane { flex: 1 1 auto !important; }
}

/* Settings modal */
.modal-overlay {
  display: none; position: fixed; inset: 0; background: rgba(0,0,0,.42);
  align-items: center; justify-content: center; z-index: 100; padding: 20px;
}
.modal-overlay.open { display: flex; }
.modal-panel {
  background: var(--ui-panel); border-radius: 12px; width: 100%; max-width: 380px;
  box-shadow: 0 10px 30px rgba(0,0,0,.25); overflow: hidden;
}
.modal-panel-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 18px; border-bottom: 1px solid var(--ui-border);
}
.modal-panel-header h2 { font-size: 14px; margin: 0; font-weight: 600; }
.modal-panel-body { padding: 18px; display: flex; flex-direction: column; gap: 16px; }
.modal-panel-body .ctrl-group { gap: 6px; padding-bottom: 14px; border-bottom: 1px solid var(--ui-border); }
.modal-panel-body .ctrl-group:last-child { border-bottom: none; padding-bottom: 0; }
.modal-panel-body .ctrl-row { flex-wrap: wrap; }
.modal-panel-footer { padding: 14px 18px; border-top: 1px solid var(--ui-border); text-align: right; }

.color-row { display: flex; gap: 16px; margin-top: 8px; flex-wrap: wrap; }
.color-field { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--ui-muted); }
.color-field input[type=color] {
  width: 28px; height: 24px; padding: 0; border: 1px solid var(--ui-border); border-radius: 4px;
  background: none; cursor: pointer;
}
.color-field input[type=color]:disabled { opacity: .4; cursor: not-allowed; }
.auto-check { display: flex; align-items: center; gap: 3px; font-size: 11px; cursor: pointer; user-select: none; }
.auto-check input { margin: 0; }

.fullscreen-panel { max-width: min(1100px, 94vw); display: flex; flex-direction: column; max-height: 92vh; }
.fullscreen-body { flex: 1; overflow: auto; padding: 32px 40px; }
.fullscreen-body .preview-content { max-width: 800px; margin: 0 auto; }