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

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #dbeafe;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #1e293b;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --success: #16a34a;
  --success-bg: #dcfce7;
  --error: #dc2626;
  --error-bg: #fee2e2;
  --warning: #d97706;
  --warning-bg: #fef3c7;
  --radius: 10px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.05);
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,.08), 0 2px 4px -2px rgba(0,0,0,.04);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,.08), 0 4px 6px -4px rgba(0,0,0,.04);
  --max-width: 1200px;
  --nav-height: 60px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--primary); text-decoration: none; transition: color .2s; }
a:hover { color: var(--primary-dark); }

/* ===== Navbar ===== */
.navbar {
  height: var(--nav-height);
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
}

.navbar .container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.navbar .logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.navbar .logo svg { width: 28px; height: 28px; }

.navbar .nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}

.navbar .nav-links a {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all .2s;
}

.navbar .nav-links a:hover {
  background: var(--primary-light);
  color: var(--primary);
}

.navbar .nav-links a.active {
  background: var(--primary);
  color: #fff;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  font-size: 24px;
  color: var(--text);
}

/* ===== Container ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  width: 100%;
}

/* ===== Main Content ===== */
.main {
  flex: 1;
  padding: 40px 0;
}

/* ===== Hero Section ===== */
.hero {
  text-align: center;
  padding: 48px 0 40px;
}

.hero h1 {
  font-size: 36px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 12px;
  letter-spacing: -0.5px;
}

.hero p {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Tool Grid ===== */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 40px;
}

.tool-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow);
  transition: all .25s ease;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.tool-card:hover {
  box-shadow: var(--shadow-lg);
  border-color: var(--primary);
  transform: translateY(-3px);
}

.tool-card .icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  margin-bottom: 4px;
}

.tool-card .icon svg { width: 24px; height: 24px; }

.tool-card h3 {
  font-size: 17px;
  font-weight: 600;
  color: var(--text);
}

.tool-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.5;
}

.tool-card .arrow {
  margin-top: auto;
  font-size: 13px;
  font-weight: 600;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 4px;
}

/* ===== Page Header ===== */
.page-header {
  margin-bottom: 28px;
}

.page-header .breadcrumb {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.page-header .breadcrumb a:hover { text-decoration: underline; }

.page-header h1 {
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}

.page-header .subtitle {
  font-size: 15px;
  color: var(--text-secondary);
}

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

.card-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

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

input[type="text"],
input[type="number"],
input[type="url"],
input[type="password"],
textarea,
select {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  font-family: inherit;
  background: var(--card-bg);
  color: var(--text);
  transition: border-color .2s, box-shadow .2s;
  outline: none;
}

input:focus,
textarea:focus,
select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, .12);
}

textarea {
  resize: vertical;
  min-height: 140px;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', 'Courier New', monospace;
  font-size: 13px;
  line-height: 1.6;
}

textarea.large { min-height: 240px; }
textarea.small { min-height: 80px; }

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all .2s;
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}
.btn-primary:hover { background: var(--primary-dark); color: #fff; }

.btn-secondary {
  background: var(--card-bg);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { border-color: var(--primary); color: var(--primary); }

.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #15803d; color: #fff; }

.btn-sm { padding: 6px 14px; font-size: 13px; }

.btn-group {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

/* ===== Output Area ===== */
.output-area {
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 8px;
  padding: 16px;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', 'Courier New', monospace;
  font-size: 13px;
  line-height: 1.6;
  overflow-x: auto;
  min-height: 60px;
  white-space: pre-wrap;
  word-break: break-all;
}

.output-area.empty {
  background: #f1f5f9;
  color: var(--text-secondary);
  font-style: italic;
}

.output-area.success { border-left: 3px solid var(--success); }
.output-area.error { border-left: 3px solid var(--error); }

/* ===== Alert / Message ===== */
.alert {
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 14px;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.alert-success { background: var(--success-bg); color: var(--success); border: 1px solid #86efac; }
.alert-error { background: var(--error-bg); color: var(--error); border: 1px solid #fca5a5; }
.alert-warning { background: var(--warning-bg); color: var(--warning); border: 1px solid #fcd34d; }
.alert-info { background: var(--primary-light); color: var(--primary); border: 1px solid #93c5fd; }

/* ===== Tabs ===== */
.tabs {
  display: flex;
  gap: 2px;
  border-bottom: 2px solid var(--border);
  margin-bottom: 20px;
  overflow-x: auto;
}

.tab {
  padding: 10px 18px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  background: none;
  border: none;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all .2s;
  white-space: nowrap;
}

.tab:hover { color: var(--primary); }
.tab.active { color: var(--primary); border-bottom-color: var(--primary); }

.tab-content { display: none; }
.tab-content.active { display: block; }

/* ===== Checkbox & Radio ===== */
.checkbox-group, .radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.checkbox-item, .radio-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: var(--text);
  cursor: pointer;
}

.checkbox-item input, .radio-item input {
  width: auto;
  accent-color: var(--primary);
}

/* ===== Grid Layouts ===== */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

/* ===== Stats / Info ===== */
.stat-row {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  padding: 12px 0;
}

.stat-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.stat-item .stat-label {
  font-size: 12px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: .5px;
}

.stat-item .stat-value {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
}

/* ===== Badge ===== */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
}

.badge-success { background: var(--success-bg); color: var(--success); }
.badge-error { background: var(--error-bg); color: var(--error); }
.badge-info { background: var(--primary-light); color: var(--primary); }

/* ===== Copy Button ===== */
.copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  background: rgba(255,255,255,.1);
  border: 1px solid rgba(255,255,255,.2);
  color: #e2e8f0;
  border-radius: 6px;
  padding: 4px 10px;
  font-size: 12px;
  cursor: pointer;
  transition: all .2s;
}

.copy-btn:hover { background: rgba(255,255,255,.2); }

/* ===== Tree View (JSON) ===== */
.json-tree {
  font-family: 'SF Mono', 'Fira Code', 'Consolas', 'Courier New', monospace;
  font-size: 13px;
  line-height: 1.8;
  padding: 16px;
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 8px;
  overflow-x: auto;
}

.json-tree .key { color: #93c5fd; }
.json-tree .string { color: #86efac; }
.json-tree .number { color: #fbbf24; }
.json-tree .boolean { color: #f472b6; }
.json-tree .null { color: #94a3b8; }
.json-tree .bracket { color: #e2e8f0; }

/* ===== Regex Highlight ===== */
.regex-match {
  background: #fef08a;
  border-radius: 2px;
  padding: 0 1px;
}

/* ===== Footer ===== */
.footer {
  background: var(--card-bg);
  border-top: 1px solid var(--border);
  padding: 32px 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: 14px;
  margin-top: auto;
}

.footer a { color: var(--text-secondary); }
.footer a:hover { color: var(--primary); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .navbar .container { padding: 0 16px; }
  .container { padding: 0 16px; }

  .nav-toggle { display: block; }

  .navbar .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 12px 16px;
    gap: 4px;
    box-shadow: var(--shadow-md);
  }

  .navbar .nav-links.open { display: flex; }

  .navbar .nav-links a {
    width: 100%;
    padding: 12px 14px;
  }

  .hero h1 { font-size: 26px; }
  .hero p { font-size: 15px; }

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

  .grid-2 { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }

  .page-header h1 { font-size: 22px; }
}

/* ===== Utility ===== */
.mt-0 { margin-top: 0; }
.mt-2 { margin-top: 8px; }
.mt-3 { margin-top: 12px; }
.mt-4 { margin-top: 16px; }
.mt-6 { margin-top: 24px; }
.mb-0 { margin-bottom: 0; }
.mb-2 { margin-bottom: 8px; }
.mb-3 { margin-bottom: 12px; }
.mb-4 { margin-bottom: 16px; }
.mb-6 { margin-bottom: 24px; }
.text-sm { font-size: 13px; }
.text-secondary { color: var(--text-secondary); }
.text-center { text-align: center; }
.text-mono { font-family: 'SF Mono', 'Fira Code', 'Consolas', 'Courier New', monospace; }
.hidden { display: none !important; }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: 8px; }
.gap-3 { gap: 12px; }
.gap-4 { gap: 16px; }
.w-full { width: 100%; }
.relative { position: relative; }