/* ===== CSS Variables & Theme ===== */
:root {
  --bg: #f5f5f5;
  --bg-card: #ffffff;
  --bg-input: #fafafa;
  --text: #1a1a1a;
  --text-secondary: #666;
  --border: #e0e0e0;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --success: #16a34a;
  --error: #dc2626;
  --warning: #d97706;
  --shadow: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-lg: 0 4px 12px rgba(0,0,0,0.1);
  --diff-add-bg: #dcfce7;
  --diff-add-text: #166534;
  --diff-del-bg: #fee2e2;
  --diff-del-text: #991b1b;
  --diff-add-dark-bg: #052e16;
  --diff-add-dark-text: #86efac;
  --diff-del-dark-bg: #450a0a;
  --diff-del-dark-text: #fca5a5;
}

[data-theme="dark"] {
  --bg: #0f0f0f;
  --bg-card: #1a1a1a;
  --bg-input: #222222;
  --text: #e5e5e5;
  --text-secondary: #999;
  --border: #333;
  --shadow: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-lg: 0 4px 12px rgba(0,0,0,0.4);
}

/* ===== Reset & Base ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
}

/* ===== Header ===== */
.header {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.header h1 {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* ===== Navigation Tabs ===== */
.nav-tabs {
  display: flex;
  gap: 4px;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
}

.nav-tab {
  padding: 10px 20px;
  cursor: pointer;
  border: none;
  background: none;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}

.nav-tab:hover { color: var(--text); }

.nav-tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ===== Theme Toggle ===== */
.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  transition: all 0.2s;
}

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

/* ===== Main Content ===== */
.main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 24px;
}

.tool-panel {
  display: none;
}

.tool-panel.active {
  display: block;
}

/* ===== Card ===== */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  box-shadow: var(--shadow);
  margin-bottom: 20px;
}

/* ===== Toolbar ===== */
.toolbar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

/* ===== Buttons ===== */
.btn {
  padding: 8px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text);
  font-size: 13px;
  cursor: pointer;
  transition: all 0.2s;
  font-weight: 500;
}

.btn:hover {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

.btn-primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

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

.btn-success {
  background: var(--success);
  color: white;
  border-color: var(--success);
}

.btn-danger {
  background: var(--error);
  color: white;
  border-color: var(--error);
}

/* ===== Textarea ===== */
.textarea-group {
  display: flex;
  gap: 16px;
}

.textarea-wrap {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.textarea-wrap label {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text-secondary);
}

textarea {
  width: 100%;
  min-height: 300px;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-input);
  color: var(--text);
  font-family: "SF Mono", "Fira Code", "Cascadia Code", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.6;
  resize: vertical;
  transition: border-color 0.2s;
}

textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

/* ===== Result Area ===== */
.result-area {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  min-height: 100px;
  font-family: "SF Mono", "Fira Code", "Cascadia Code", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-all;
  max-height: 500px;
  overflow: auto;
}

/* ===== JSON Highlight ===== */
.json-key { color: #0550ae; }
.json-string { color: #0a3069; }
.json-number { color: #0550ae; }
.json-boolean { color: #cf222e; }
.json-null { color: #6e7781; }

[data-theme="dark"] .json-key { color: #79c0ff; }
[data-theme="dark"] .json-string { color: #a5d6ff; }
[data-theme="dark"] .json-number { color: #79c0ff; }
[data-theme="dark"] .json-boolean { color: #ff7b72; }
[data-theme="dark"] .json-null { color: #8b949e; }

/* ===== Diff ===== */
.diff-container {
  display: flex;
  gap: 16px;
}

.diff-pane {
  flex: 1;
  overflow: auto;
  max-height: 500px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-input);
}

.diff-pane-header {
  padding: 8px 12px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
  background: var(--bg-card);
  position: sticky;
  top: 0;
}

.diff-line {
  padding: 2px 12px;
  font-family: "SF Mono", "Fira Code", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.5;
  white-space: pre;
  border-left: 3px solid transparent;
}

.diff-line-add {
  background: var(--diff-add-bg);
  border-left-color: var(--success);
  color: var(--diff-add-text);
}

.diff-line-del {
  background: var(--diff-del-bg);
  border-left-color: var(--error);
  color: var(--diff-del-text);
}

[data-theme="dark"] .diff-line-add {
  background: var(--diff-add-dark-bg);
  color: var(--diff-add-dark-text);
}

[data-theme="dark"] .diff-line-del {
  background: var(--diff-del-dark-bg);
  color: var(--diff-del-dark-text);
}

.diff-line-num {
  display: inline-block;
  width: 40px;
  color: var(--text-secondary);
  text-align: right;
  margin-right: 12px;
  user-select: none;
  font-size: 12px;
}

.diff-stats {
  padding: 8px 16px;
  font-size: 13px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}

.diff-stats .add-count { color: var(--success); font-weight: 600; }
.diff-stats .del-count { color: var(--error); font-weight: 600; }

/* ===== Timestamp ===== */
.ts-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.ts-section {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.ts-section h3 {
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
}

.ts-row {
  display: flex;
  gap: 8px;
  align-items: center;
}

.ts-row input, .ts-row select {
  flex: 1;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-input);
  color: var(--text);
  font-size: 14px;
  font-family: "SF Mono", "Fira Code", Menlo, Consolas, monospace;
}

.ts-row input:focus, .ts-row select:focus {
  outline: none;
  border-color: var(--accent);
}

.ts-now {
  display: flex;
  gap: 16px;
  padding: 16px;
  background: var(--bg-input);
  border-radius: 8px;
  border: 1px solid var(--border);
}

.ts-now-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.ts-now-label {
  font-size: 12px;
  color: var(--text-secondary);
}

.ts-now-value {
  font-family: "SF Mono", "Fira Code", Menlo, Consolas, monospace;
  font-size: 16px;
  font-weight: 600;
  color: var(--accent);
}

/* ===== Toast ===== */
.toast {
  position: fixed;
  top: 70px;
  right: 24px;
  padding: 10px 20px;
  border-radius: 8px;
  color: white;
  font-size: 14px;
  font-weight: 500;
  z-index: 1000;
  opacity: 0;
  transform: translateY(-10px);
  transition: all 0.3s;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

.toast-success { background: var(--success); }
.toast-error { background: var(--error); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .textarea-group { flex-direction: column; }
  .diff-container { flex-direction: column; }
  .ts-grid { grid-template-columns: 1fr; }
  .header h1 { font-size: 15px; }
  .nav-tab { padding: 8px 12px; font-size: 13px; }
  .main { padding: 16px; }
}