:root {
  --bg: #F7F7F5;
  --card: #FFFFFF;
  --text: #222222;
  --muted: #666666;
  --border: #DEDED9;
  --accent: #315C4C;
  --accent-bg: #EDF3EF;
  --error: #A12B2B;
  --success: #2A5A3A;
  --mono: ui-monospace, "SF Mono", "Cascadia Code", "Segoe UI Mono", Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --radius: 6px;
  --max: 1120px;
}

*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.55;
}

a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }
img, svg { display: block; max-width: 100%; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.container {
  width: min(var(--max), calc(100% - 40px));
  margin-inline: auto;
}

/* Header */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 50;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 56px;
  padding-block: 8px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 650;
  font-size: 16px;
  letter-spacing: -0.02em;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--accent-bg);
  color: var(--accent);
  font: 600 11px var(--mono);
}

.main-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 18px;
  font-size: 13px;
  color: var(--muted);
}

.main-nav a:hover { color: var(--accent); }

/* Hero */
.hero {
  padding: 48px 0 28px;
}

.hero h1 {
  margin: 0 0 12px;
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 650;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.hero-lead {
  margin: 0 0 24px;
  max-width: 52ch;
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* Tool nav */
.tool-nav-section {
  padding-bottom: 36px;
}

.tool-nav {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.tool-nav-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 16px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 0.15s, background 0.15s;
}

.tool-nav-item:hover {
  border-color: var(--accent);
  background: var(--accent-bg);
}

.tool-nav-label {
  font-weight: 600;
  font-size: 14px;
}

.tool-nav-desc {
  font-size: 12px;
  color: var(--muted);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 9px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card);
  color: var(--text);
  font-size: 13px;
  font-weight: 550;
  line-height: 1.3;
  white-space: nowrap;
  transition: background 0.12s, border-color 0.12s, color 0.12s;
}

.btn:hover { background: #f0f0ee; border-color: #c8c8c2; }
.btn:active { background: #e8e8e4; }

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.btn-primary:hover {
  background: #274a3d;
  border-color: #274a3d;
  color: #fff;
}

.btn-secondary {
  background: var(--accent-bg);
  border-color: #c5d4cb;
  color: var(--accent);
}
.btn-secondary:hover {
  background: #e0ebe4;
  border-color: #a8c0b0;
}

.btn-ghost {
  background: transparent;
  border-color: transparent;
  color: var(--muted);
}
.btn-ghost:hover {
  background: #eee;
  color: var(--text);
  border-color: transparent;
}

.btn-sm {
  padding: 5px 10px;
  font-size: 12px;
}

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

/* Tool sections */
.tool-section {
  padding-bottom: 40px;
}

.tool-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.tool-card-header {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 20px;
}

.tool-card-header h2 {
  margin: 0 0 4px;
  font-size: 1.25rem;
  font-weight: 650;
  letter-spacing: -0.02em;
}

.tool-card-desc {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.tool-card-actions {
  display: flex;
  gap: 6px;
  flex-shrink: 0;
}

/* Form elements */
.field-label {
  display: block;
  margin-bottom: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
}

.field-hint {
  margin: 6px 0 0;
  font-size: 12px;
  color: var(--muted);
}

.text-input,
.code-input,
select.text-input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--text);
  transition: border-color 0.12s;
}

.text-input:focus,
.code-input:focus,
select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-bg);
}

.code-input {
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.5;
  resize: vertical;
  min-height: 120px;
}

.mono { font-family: var(--mono); font-size: 13px; }

.checkbox-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  cursor: pointer;
  user-select: none;
}

.checkbox-label input {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
}

.control-group { margin-bottom: 14px; }
.control-group.grow { flex: 1; min-width: 0; }

/* JSON workspace */
.json-workspace {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 16px;
  align-items: start;
}

.json-panel {
  min-width: 0;
}

.panel-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 6px;
}

.panel-top .field-label { margin-bottom: 0; }

.panel-meta {
  margin-top: 6px;
  font-size: 12px;
  color: var(--muted);
}

.json-actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-top: 28px;
  min-width: 120px;
}

.indent-group {
  margin-top: 8px;
}

.indent-group label {
  display: block;
  margin-bottom: 4px;
  font-size: 12px;
  color: var(--muted);
}

.indent-group select {
  width: 100%;
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  font-size: 13px;
}

.status-bar {
  margin-top: 16px;
  padding: 10px 14px;
  border-radius: var(--radius);
  background: var(--bg);
  border: 1px solid var(--border);
  font-size: 13px;
  color: var(--muted);
}

.status-bar.success {
  background: var(--accent-bg);
  border-color: #c5d4cb;
  color: var(--success);
}

.status-bar.error {
  background: #faf0f0;
  border-color: #e8c8c8;
  color: var(--error);
}

/* Timestamp / shared blocks */
.tool-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
}

.block-title {
  margin: 0 0 14px;
  font-size: 15px;
  font-weight: 600;
}

.output-box {
  margin-top: 14px;
  padding: 12px 14px;
  min-height: 48px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  font-size: 13px;
  line-height: 1.55;
  color: var(--text);
}

.output-box:empty::before {
  content: "Result will appear here";
  color: var(--muted);
}

.status-text {
  margin-top: 8px;
  font-size: 13px;
  color: var(--muted);
  min-height: 1.2em;
}

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

/* UUID */
.uuid-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 16px 24px;
  margin-bottom: 8px;
}

.uuid-controls .control-group {
  margin-bottom: 0;
  min-width: 140px;
}

.uuid-controls .btn-row {
  margin-top: 0;
}

/* Regex */
.regex-form { margin-bottom: 4px; }

.regex-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.flags-group {
  width: 120px;
  flex-shrink: 0;
}

/* Privacy */
.privacy-section {
  padding: 32px 0 48px;
}

.privacy-section h2 {
  margin: 0 0 10px;
  font-size: 1.15rem;
  font-weight: 650;
}

.privacy-section p {
  margin: 0;
  max-width: 60ch;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--card);
  padding: 28px 0;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 24px;
}

.footer-note {
  margin: 0;
  flex: 1;
  font-size: 13px;
  color: var(--muted);
}

.footer-copy {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
}

/* Toast */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  padding: 10px 18px;
  background: var(--text);
  color: #fff;
  border-radius: var(--radius);
  font-size: 13px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
  z-index: 100;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Responsive */
@media (max-width: 900px) {
  .tool-nav {
    grid-template-columns: 1fr 1fr;
  }

  .json-workspace {
    grid-template-columns: 1fr;
  }

  .json-actions {
    flex-direction: row;
    flex-wrap: wrap;
    padding-top: 0;
    min-width: 0;
  }

  .indent-group {
    margin-top: 0;
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .indent-group label { margin-bottom: 0; }
  .indent-group select { width: auto; }

  .tool-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .container {
    width: calc(100% - 28px);
  }

  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding-block: 12px;
  }

  .main-nav {
    gap: 4px 14px;
  }

  .hero {
    padding-top: 32px;
  }

  .tool-nav {
    grid-template-columns: 1fr;
  }

  .tool-card {
    padding: 18px;
  }

  .uuid-controls {
    flex-direction: column;
    align-items: stretch;
  }

  .flags-group {
    width: 100%;
  }
}