:root {
  --bg: #ffffff;
  --bg-secondary: #f8fafc;
  --text: #0f172a;
  --text-secondary: #64748b;
  --card: #ffffff;
  --card-border: #e2e8f0;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --accent-light: #eff6ff;
  --success: #22c55e;
  --error: #ef4444;
  --warning: #f59e0b;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
  --transition: 0.2s ease;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", monospace;
  --header-height: 64px;
  --max-width: 1200px;
  --sidebar-width: 240px;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --bg-secondary: #1e293b;
  --text: #e2e8f0;
  --text-secondary: #94a3b8;
  --card: #1e293b;
  --card-border: #334155;
  --accent: #60a5fa;
  --accent-hover: #93c5fd;
  --accent-light: #1e3a5f;
  --success: #4ade80;
  --error: #f87171;
  --warning: #fbbf24;
  --shadow: 0 1px 3px rgba(0,0,0,0.3), 0 1px 2px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.25), 0 2px 4px rgba(0,0,0,0.2);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.3), 0 4px 6px rgba(0,0,0,0.2);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  transition: background var(--transition), color var(--transition);
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--card);
  border-bottom: 1px solid var(--card-border);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.header-inner {
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  white-space: nowrap;
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: var(--accent);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
}

.search-wrapper {
  flex: 1;
  max-width: 480px;
  position: relative;
}

.search-input {
  width: 100%;
  padding: 10px 16px 10px 40px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  background: var(--bg-secondary);
  color: var(--text);
  font-size: 14px;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.15);
}

.search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
}

.search-icon svg { width: 18px; height: 18px; }

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.theme-toggle {
  width: 40px;
  height: 40px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
}

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

.sidebar-toggle {
  width: 40px;
  height: 40px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text);
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
}

.sidebar-toggle:hover { border-color: var(--accent); color: var(--accent); }

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 150;
}

/* Layout Wrapper */
.layout-wrapper {
  display: flex;
  min-height: calc(100vh - var(--header-height));
}

/* Sidebar */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  position: sticky;
  top: var(--header-height);
  height: calc(100vh - var(--header-height));
  overflow-y: auto;
  background: var(--card);
  border-right: 1px solid var(--card-border);
  padding: 8px 0;
  display: flex;
  flex-direction: column;
}

.sidebar a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition);
  border-left: 3px solid transparent;
}

.sidebar a:hover {
  color: var(--text);
  background: var(--bg-secondary);
}

.sidebar a.active {
  color: var(--accent);
  background: var(--accent-light);
  border-left-color: var(--accent);
  font-weight: 600;
}

.sidebar a svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.sidebar-divider {
  height: 1px;
  background: var(--card-border);
  margin: 8px 16px;
}

/* Main */
.main-content {
  flex: 1;
  min-width: 0;
  padding: 32px 32px 64px;
}

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

.hero h1 {
  font-size: 36px;
  font-weight: 800;
  margin-bottom: 12px;
  background: linear-gradient(135deg, var(--accent), #a855f7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

/* Category Grid */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 32px;
}

.category-card {
  display: block;
  padding: 24px;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: all var(--transition);
  cursor: pointer;
  color: var(--text);
}

.category-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent);
  color: var(--text);
}

.category-card-icon {
  width: 48px;
  height: 48px;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  margin-bottom: 16px;
}

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

.category-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 6px;
}

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

.category-card .tool-count {
  margin-top: 12px;
  font-size: 13px;
  color: var(--accent);
  font-weight: 500;
}

/* Home - Grouped Tool Sections */
.home-category-section {
  margin-bottom: 36px;
}

.home-category-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--card-border);
}

.home-category-header .cat-icon {
  width: 32px;
  height: 32px;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
}

.home-category-header .cat-icon svg { width: 18px; height: 18px; }

.home-category-header h2 {
  font-size: 18px;
  font-weight: 600;
  flex: 1;
}

.home-category-header a {
  font-size: 13px;
  color: var(--text-secondary);
}

.home-category-header a:hover { color: var(--accent); }

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .separator { color: var(--card-border); }

/* Category Page */
.category-header {
  margin-bottom: 32px;
}

.category-header h1 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.category-header h1 .cat-icon {
  width: 40px;
  height: 40px;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
}

.category-header h1 .cat-icon svg { width: 22px; height: 22px; }

.category-header p { color: var(--text-secondary); font-size: 16px; }

/* Tool List */
.tool-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}

.tool-card {
  display: block;
  padding: 20px;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: all var(--transition);
  color: var(--text);
}

.tool-card:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent);
  color: var(--text);
}

.tool-card h3 { font-size: 16px; font-weight: 600; margin-bottom: 4px; }
.tool-card p { font-size: 14px; color: var(--text-secondary); }

/* Tool Page */
.tool-page h1 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
}

.tool-page .tool-desc {
  color: var(--text-secondary);
  font-size: 16px;
  margin-bottom: 32px;
}

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

.input-group, .output-group {
  margin-bottom: 20px;
}

.input-group label, .output-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

textarea, input[type="text"], input[type="url"], input[type="number"], select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.5;
  resize: vertical;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

textarea:focus, input:focus, select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.15);
}

textarea[readonly] { opacity: 0.85; cursor: default; }

.button-group {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font);
}

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

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text);
  border-color: var(--card-border);
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

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

.btn-success { background: var(--success); color: #fff; }
.btn-error { background: var(--error); color: #fff; }

.tool-help {
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--card-border);
}

.tool-help h2 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
}

.tool-help p, .tool-help li {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.tool-help ul, .tool-help ol {
  padding-left: 20px;
  margin: 8px 0;
}

/* Two-column layout for input/output */
.tool-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

@media (max-width: 768px) {
  .tool-columns { grid-template-columns: 1fr; }
}

/* Options row */
.options-row {
  display: flex;
  gap: 16px;
  margin-bottom: 16px;
  flex-wrap: wrap;
  align-items: center;
}

.options-row label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  cursor: pointer;
}

.options-row select, .options-row input[type="text"] {
  width: auto;
  min-width: 140px;
}

/* Toast notification */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  padding: 12px 20px;
  background: var(--text);
  color: var(--bg);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  opacity: 0;
  transform: translateY(10px);
  transition: all 0.3s ease;
  pointer-events: none;
}

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

/* No results */
.no-results {
  text-align: center;
  padding: 48px 20px;
  color: var(--text-secondary);
  display: none;
}

.no-results svg { margin-bottom: 16px; opacity: 0.5; }
.no-results p { font-size: 16px; }

/* Footer */
.site-footer {
  text-align: center;
  padding: 24px;
  color: var(--text-secondary);
  font-size: 13px;
  border-top: 1px solid var(--card-border);
}

/* Utility */
.hidden { display: none !important; }

/* Responsive */
@media (max-width: 768px) {
  .sidebar-toggle { display: flex; }
  .sidebar {
    position: fixed;
    left: -260px;
    top: 0;
    height: 100vh;
    z-index: 200;
    transition: left 0.3s ease;
    padding-top: calc(var(--header-height) + 8px);
  }
  .sidebar.open { left: 0; }
  .sidebar-overlay.open { display: block; }
  .layout-wrapper { display: block; }
  .main-content { padding: 20px 16px 48px; }
}

@media (max-width: 640px) {
  .header-inner { padding: 0 16px; }
  .search-wrapper { max-width: none; }
  .hero h1 { font-size: 28px; }
  .hero p { font-size: 16px; }
  .category-grid { grid-template-columns: 1fr; }
  .tool-list { grid-template-columns: 1fr; }
}

/* Scrollbar */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg-secondary); }
::-webkit-scrollbar-thumb { background: var(--card-border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-secondary); }

/* Table */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.data-table th, .data-table td {
  padding: 10px 14px;
  border: 1px solid var(--card-border);
  text-align: left;
}

.data-table th {
  background: var(--bg-secondary);
  font-weight: 600;
}

.data-table tr:hover td { background: var(--accent-light); }

/* Select custom */
select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}