:root {
  --bg: #1e1e1e;
  --panel: #252526;
  --border: #3c3c3c;
  --text: #d4d4d4;
  --accent: #0e7490;
  --accent-hover: #0891b2;
  --error: #f87171;
  --tok-key: #9cdcfe;
  --tok-string: #ce9178;
  --tok-number: #b5cea8;
  --tok-boolean: #569cd6;
  --tok-null: #808080;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
  margin: 0;
}

body {
  display: flex;
  flex-direction: column;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

header {
  padding: 0.75rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}

.header-inner {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
  max-width: 1600px;
  margin: 0 auto;
}

nav {
  display: flex;
  gap: 0.5rem;
  margin-right: auto;
}

nav a {
  color: var(--text);
  text-decoration: none;
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  font-size: 0.9rem;
}

nav a:hover {
  background: var(--border);
}

nav a.active {
  background: var(--accent);
  color: white;
}

.settings-wrap {
  position: relative;
}

.gear-btn {
  width: auto;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.4rem 0.6rem;
  font-size: 1rem;
  line-height: 1;
}

.gear-btn:hover {
  background: var(--border);
}

.settings-panel {
  position: absolute;
  top: calc(100% + 0.5rem);
  right: 0;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 0.6rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.65rem 0.75rem;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.45);
  white-space: nowrap;
  z-index: 10;
}

.settings-panel[hidden] {
  display: none;
}

.settings-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.settings-panel label {
  font-size: 0.8rem;
  color: #9d9d9d;
}

.settings-panel input[type="number"] {
  width: 3rem;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.4rem;
  font-size: 0.85rem;
  outline: none;
}

.settings-panel input[type="number"]:focus {
  border-color: var(--accent);
}

.settings-panel input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  accent-color: var(--accent);
}

.settings-label-group {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.info-wrap {
  position: relative;
  display: flex;
}

.info-btn {
  width: auto;
  background: transparent;
  border: none;
  color: #9d9d9d;
  padding: 0;
  font-size: 0.95rem;
  line-height: 1;
  cursor: pointer;
}

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

.info-popup {
  position: absolute;
  top: calc(100% + 0.4rem);
  right: 0;
  width: 200px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.55rem 0.65rem;
  font-size: 0.75rem;
  line-height: 1.4;
  color: var(--text);
  white-space: normal;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.45);
  z-index: 20;
}

.info-popup[hidden] {
  display: none;
}

.page-intro {
  max-width: 1600px;
  margin: 0.75rem auto 0;
  padding: 0 1.25rem;
  font-size: 0.8rem;
  font-weight: 400;
  color: #9d9d9d;
}

main {
  flex: 1;
  display: flex;
  min-height: 0;
  width: 100%;
  max-width: 1600px;
  margin: 0 auto;
  padding: 1rem;
  gap: 1rem;
}

.pane {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.pane label {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #9d9d9d;
  margin-bottom: 0.4rem;
}

textarea {
  flex: 1;
  resize: none;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.75rem;
  font-family: "SF Mono", Consolas, Menlo, monospace;
  font-size: 0.85rem;
  line-height: 1.5;
  outline: none;
}

textarea:focus {
  border-color: var(--accent);
}

textarea.error {
  border-color: var(--error);
}

.output-pane {
  flex: 1;
  margin: 0;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.75rem;
  font-family: "SF Mono", Consolas, Menlo, monospace;
  font-size: 0.85rem;
  line-height: 1.5;
  white-space: pre-wrap;
  word-break: break-word;
  overflow-y: auto;
  outline: none;
}

.output-pane:focus {
  border-color: var(--accent);
}

.output-pane:empty::before {
  content: attr(data-placeholder);
  color: #6a6a6a;
}

.tok-key {
  color: var(--tok-key);
}

.tok-string {
  color: var(--tok-string);
}

.tok-number {
  color: var(--tok-number);
}

.tok-boolean {
  color: var(--tok-boolean);
}

.tok-null {
  color: var(--tok-null);
}

.bracket-match {
  background: rgba(255, 215, 0, 0.35);
  outline: 1px solid rgba(255, 215, 0, 0.6);
  border-radius: 2px;
}

.editor-wrap,
.field-wrap {
  position: relative;
  flex: 1;
  min-height: 0;
  display: flex;
}

.input-highlight {
  position: absolute;
  inset: 0;
  margin: 0;
  pointer-events: none;
  z-index: 0;
}

.input-textarea {
  position: absolute;
  inset: 0;
  z-index: 1;
  background: transparent;
  color: transparent;
  caret-color: var(--text);
}

.input-textarea::placeholder {
  color: #6a6a6a;
  opacity: 1;
}

.copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  z-index: 2;
  width: auto;
  padding: 0.3rem 0.45rem;
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.85rem;
  line-height: 1;
  border-radius: 6px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s ease;
}

.editor-wrap:hover .copy-btn,
.field-wrap:hover .copy-btn,
.copy-btn:focus-visible {
  opacity: 1;
  pointer-events: auto;
}

.copy-btn:hover {
  background: var(--border);
}

.copy-btn.copied {
  border-color: var(--accent);
  color: var(--accent);
}

.controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  width: 140px;
  flex-shrink: 0;
}

.controls-buttons {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  width: 100%;
}

.ad-slot {
  display: flex;
  justify-content: center;
}

.ad-placeholder {
  width: 140px;
  height: 280px;
  max-width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px dashed var(--border);
  border-radius: 8px;
}

.ad-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #6a6a6a;
}

button {
  width: 100%;
  padding: 0.6rem 0.75rem;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
}

button:hover {
  background: var(--accent-hover);
}

button.secondary {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}

#swap {
  font-size: 1.1rem;
  line-height: 1;
}

button.secondary:hover {
  background: var(--border);
}

.status {
  font-size: 0.75rem;
  color: var(--error);
  text-align: center;
  min-height: 1rem;
}

@media (max-width: 720px) {
  main {
    flex-direction: column;
  }
  .controls {
    width: 100%;
  }
  .controls-buttons {
    width: 100%;
    flex-direction: row;
  }
  .ad-slot {
    display: none;
  }
}

@media (max-width: 420px) {
  header {
    gap: 0.5rem;
    padding: 0.6rem 0.85rem;
  }
  nav {
    gap: 0.3rem;
  }
  nav a {
    padding: 0.35rem 0.55rem;
    font-size: 0.8rem;
  }
  .gear-btn {
    padding: 0.35rem 0.5rem;
    font-size: 0.9rem;
  }
}