:root {
  --bg: #0f172a;
  --bg-soft: #1e293b;
  --bg-panel: #1e293b;
  --border: #334155;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --accent: #38bdf8;
  --accent-soft: rgba(56, 189, 248, 0.15);
  --radius: 12px;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
}

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

.container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header / nav */
.site-header {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  padding-top: 12px;
  padding-bottom: 12px;
}

.brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: 0.5px;
}

.brand:hover {
  color: var(--accent);
}

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

.nav-btn {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 8px 14px;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.nav-btn:hover {
  color: var(--text);
  background: var(--accent-soft);
}

.nav-btn.active {
  color: var(--accent);
  background: var(--accent-soft);
  border-color: var(--accent);
  font-weight: 600;
}

/* Main panels */
main.container {
  flex: 1;
  padding-top: 32px;
  padding-bottom: 40px;
}

.panel h1 {
  margin: 0 0 4px;
  font-size: 1.7rem;
}

.subtitle {
  margin: 0 0 20px;
  color: var(--text-muted);
}

.input-area {
  width: 100%;
  min-height: 220px;
  resize: vertical;
  background: var(--bg-soft);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-family: Consolas, "Cascadia Mono", "Segoe UI", monospace;
  font-size: 0.95rem;
  line-height: 1.5;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.input-area:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.input-area::placeholder {
  color: var(--text-muted);
}

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
  margin-top: 18px;
}

.stat-card {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 14px;
  text-align: center;
}

.stat-value {
  display: block;
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.stat-label {
  display: block;
  margin-top: 6px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Markdown panel */
.md-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 14px;
  flex-wrap: wrap;
}

.md-btn {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 7px 12px;
  font-size: 0.88rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.md-btn:hover {
  color: var(--text);
}

.md-btn.active {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
  font-weight: 600;
}

.md-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.md-layout.split {
  grid-template-columns: 1fr 1fr;
}

@media (max-width: 640px) {
  .md-layout.split {
    grid-template-columns: 1fr;
  }
}

.md-input {
  min-height: 320px;
}

.preview-area {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  min-height: 320px;
  overflow: auto;
  line-height: 1.6;
}

.preview-area h1,
.preview-area h2,
.preview-area h3,
.preview-area h4 {
  border-bottom: 1px solid var(--border);
  padding-bottom: 6px;
}

.preview-area a {
  color: var(--accent);
}

.preview-area code {
  background: var(--bg);
  border-radius: 4px;
  padding: 2px 5px;
  font-family: Consolas, "Cascadia Mono", monospace;
}

.preview-area pre {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  overflow: auto;
}

.preview-area pre code {
  background: transparent;
  padding: 0;
}

.preview-area blockquote {
  margin: 0;
  padding: 2px 14px;
  border-left: 4px solid var(--accent);
  color: var(--text-muted);
}

.preview-area table {
  border-collapse: collapse;
}

.preview-area th,
.preview-area td {
  border: 1px solid var(--border);
  padding: 6px 10px;
}

.preview-area img {
  max-width: 100%;
}

.md-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 14px;
  flex-wrap: wrap;
}

.btn {
  background: var(--accent);
  color: #0f172a;
  border: none;
  border-radius: 8px;
  padding: 9px 16px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s ease, transform 0.1s ease;
}

.btn:hover {
  opacity: 0.9;
}

.btn:active {
  transform: scale(0.98);
}

.hint {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--bg-soft);
  padding: 18px 0;
}

.site-footer p {
  margin: 0 0 6px;
  color: var(--text-muted);
  font-size: 0.85rem;
  text-align: center;
}

.footer-link {
  margin: 0;
}

.footer-visits {
  margin: 0 0 6px;
}

.footer-visits #visit-count {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

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

.footer-link a:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .site-header .container {
    flex-direction: column;
    align-items: stretch;
    text-align: center;
  }

  .tool-nav {
    justify-content: center;
  }
}

/* Sub-navigation */
.sub-nav {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 18px;
}

.sub-btn {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.sub-btn:hover {
  color: var(--text);
}

.sub-btn.active {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
  font-weight: 600;
}

.sub-panel h2 {
  margin: 0 0 4px;
  font-size: 1.4rem;
}

.sub-panel .subtitle {
  margin: 0 0 16px;
}

/* Tool controls */
.btn-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 14px 0;
  align-items: center;
}

.controls {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  align-items: center;
  margin: 14px 0;
}

.control {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
  font-size: 0.88rem;
  cursor: pointer;
}

.control input[type="checkbox"] {
  accent-color: var(--accent);
  cursor: pointer;
}

.control input[type="number"] {
  width: 70px;
}

.field-input {
  background: var(--bg-soft);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.15s ease;
}

.field-input:focus {
  border-color: var(--accent);
}

.input-area.output {
  min-height: 160px;
}

.pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

@media (max-width: 640px) {
  .pair {
    grid-template-columns: 1fr;
  }
}

/* Keyword / list output */
.klist {
  font-family: Consolas, "Cascadia Mono", monospace;
  font-size: 0.85rem;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 14px;
  max-height: 340px;
  overflow: auto;
  white-space: pre-wrap;
  line-height: 1.6;
}

.klist .lead {
  color: var(--text);
}

.klist .muted {
  color: var(--text-muted);
}

/* Diff output */
.diff {
  font-family: Consolas, "Cascadia Mono", monospace;
  font-size: 0.85rem;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 12px;
  max-height: 360px;
  overflow: auto;
  white-space: pre;
  line-height: 1.6;
}

.diff .ctx {
  display: block;
  color: var(--text-muted);
}

.diff .add {
  display: block;
  background: rgba(34, 197, 94, 0.15);
  color: #86efac;
}

.diff .del {
  display: block;
  background: rgba(239, 68, 68, 0.15);
  color: #fca5a5;
}

/* Syntax highlight tokens */
.tok-c { color: #94a3b8; font-style: italic; }
.tok-s { color: #86efac; }
.tok-n { color: #fdba74; }
.tok-k { color: #c4b5fd; font-weight: 600; }
.tok-f { color: #fde047; }
.tok-t { color: #38bdf8; }
.tok-a { color: #fbbf24; }
.tok-sel { color: #67e8f9; }
.tok-p { color: #93c5fd; }
.tok-at { color: #f472b6; }
.tok-e { color: #f472b6; }