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

:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --text-color: #1f2937;
  --text-light: #6b7280;
  --border-color: #e5e7eb;
  --bg-gray: #f9fafb;
  --success-color: #10b981;
  --error-color: #ef4444;
  --warning-color: #f59e0b;
  --border-radius: 8px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: #fff;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

/* ===== Header ===== */
.site-header {
  background-color: #fff;
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-color);
  text-decoration: none;
}

.site-header nav {
  display: flex;
  gap: 1.5rem;
}

.site-header nav a {
  color: var(--text-color);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

.site-header nav a:hover {
  color: var(--primary-color);
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  background-color: var(--bg-gray);
  padding: 0.75rem 0;
  font-size: 0.875rem;
  border-bottom: 1px solid var(--border-color);
}

.breadcrumb a {
  color: var(--primary-color);
  text-decoration: none;
}

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

.breadcrumb span {
  color: var(--text-light);
}

/* ===== Hero Section ===== */
.hero {
  text-align: center;
  padding: 3rem 0 2rem;
}

.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  color: var(--text-color);
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-light);
  margin-bottom: 2rem;
}

.search-box {
  max-width: 600px;
  margin: 0 auto;
}

.search-box input {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius);
  transition: border-color 0.2s;
}

.search-box input:focus {
  outline: none;
  border-color: var(--primary-color);
}

/* ===== Sections ===== */
main section {
  margin: 3rem 0;
}

main h2 {
  font-size: 1.875rem;
  margin-bottom: 1.5rem;
  color: var(--text-color);
}

/* ===== Categories Grid ===== */
.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.category-card {
  background-color: #fff;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 1.5rem;
  transition: box-shadow 0.2s, transform 0.2s;
}

.category-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.category-card h2 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.category-card h2 a {
  color: var(--text-color);
  text-decoration: none;
}

.category-card h2 a:hover {
  color: var(--primary-color);
}

.category-card p {
  color: var(--text-light);
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.tool-count {
  display: inline-block;
  font-size: 0.75rem;
  color: var(--text-light);
  background-color: var(--bg-gray);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
}

/* ===== Tools Grid ===== */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.tool-card {
  background-color: #fff;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 1.5rem;
  transition: box-shadow 0.2s, transform 0.2s;
}

.tool-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.tool-card h2,
.tool-card h3 {
  font-size: 1.125rem;
  margin-bottom: 0.5rem;
}

.tool-card h2 a,
.tool-card h3 a {
  color: var(--text-color);
  text-decoration: none;
}

.tool-card h2 a:hover,
.tool-card h3 a:hover {
  color: var(--primary-color);
}

.tool-card p {
  color: var(--text-light);
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.category-tag {
  display: inline-block;
  font-size: 0.75rem;
  color: var(--primary-color);
  background-color: rgba(37, 99, 235, 0.1);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
}

/* ===== Tool Page ===== */
.tool-page {
  max-width: 900px;
  margin: 2rem auto;
}

.tool-page h1 {
  font-size: 2.25rem;
  margin-bottom: 1rem;
}

.tool-intro {
  margin-bottom: 2rem;
  padding: 1rem;
  background-color: var(--bg-gray);
  border-radius: var(--border-radius);
  border-left: 4px solid var(--primary-color);
}

.privacy-features {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1rem;
}

.privacy-features li {
  display: flex;
  align-items: center;
  font-size: 0.875rem;
  color: var(--success-color);
}

.privacy-features li::before {
  content: "✓";
  margin-right: 0.5rem;
  font-weight: bold;
}

/* ===== Tool Panel ===== */
.tool-panel {
  background-color: #fff;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-color);
}

.form-group input[type="text"],
.form-group input[type="number"],
.form-group input[type="tel"],
.form-group input[type="url"],
.form-group input[type="file"],
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary-color);
}

.form-group textarea {
  min-height: 150px;
  resize: vertical;
  font-family: 'Monaco', 'Consolas', monospace;
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  text-decoration: none;
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}

.btn:active {
  transform: scale(0.98);
}

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

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

.btn-secondary {
  background-color: var(--text-light);
  color: #fff;
}

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

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

.btn-group {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

/* ===== Output Area ===== */
.output-area {
  margin-top: 1.5rem;
  padding: 1.5rem;
  background-color: var(--bg-gray);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
}

.output-preview {
  text-align: center;
  padding: 2rem;
  background-color: #fff;
  border-radius: var(--border-radius);
  min-height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.output-info {
  margin-top: 1rem;
  font-size: 0.875rem;
  color: var(--text-light);
}

.status-message {
  padding: 0.75rem;
  border-radius: var(--border-radius);
  margin-bottom: 1rem;
  font-size: 0.875rem;
}

.status-success {
  background-color: rgba(16, 185, 129, 0.1);
  color: var(--success-color);
  border: 1px solid var(--success-color);
}

.status-error {
  background-color: rgba(239, 68, 68, 0.1);
  color: var(--error-color);
  border: 1px solid var(--error-color);
}

/* ===== Ad Slots ===== */
.ad-slot {
  min-height: 250px;
  background-color: var(--bg-gray);
  border: 2px dashed var(--border-color);
  border-radius: var(--border-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 2rem 0;
  color: var(--text-light);
  font-size: 0.875rem;
}

.ad-slot::before {
  content: "Advertisement";
}

/* ===== How It Works & FAQ ===== */
.how-it-works,
.faq {
  margin: 3rem 0;
}

.how-it-works h2,
.faq h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.faq-item {
  margin-bottom: 1.5rem;
}

.faq-item h3 {
  font-size: 1.125rem;
  margin-bottom: 0.5rem;
  color: var(--text-color);
}

.faq-item p {
  color: var(--text-light);
}

/* ===== Related Tools ===== */
.related-tools {
  margin: 3rem 0;
}

.related-tools h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.tool-links {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 0.75rem;
}

.tool-links li a {
  display: block;
  padding: 0.75rem 1rem;
  background-color: var(--bg-gray);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  text-decoration: none;
  color: var(--primary-color);
  font-weight: 500;
  transition: background-color 0.2s, border-color 0.2s;
}

.tool-links li a:hover {
  background-color: rgba(37, 99, 235, 0.05);
  border-color: var(--primary-color);
}

/* ===== SEO Content ===== */
.seo-content {
  margin: 3rem 0;
  padding: 2rem;
  background-color: var(--bg-gray);
  border-radius: var(--border-radius);
}

.seo-content h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.seo-content p {
  margin-bottom: 1rem;
  line-height: 1.8;
}

.category-description {
  font-size: 1.125rem;
  color: var(--text-light);
  margin-bottom: 2rem;
}

/* ===== Footer ===== */
.site-footer {
  background-color: var(--text-color);
  color: #fff;
  padding: 2rem 0;
  margin-top: 4rem;
}

.site-footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.site-footer nav {
  display: flex;
  gap: 1.5rem;
}

.site-footer nav a {
  color: #fff;
  text-decoration: none;
  transition: opacity 0.2s;
}

.site-footer nav a:hover {
  opacity: 0.8;
}

/* ===== Text Compare Specific ===== */
.diff-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.diff-panel {
  background-color: #fff;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 1rem;
  font-family: 'Monaco', 'Consolas', monospace;
  font-size: 0.875rem;
  white-space: pre-wrap;
  word-break: break-word;
  max-height: 500px;
  overflow-y: auto;
}

.diff-deleted {
  background-color: #fee;
  color: #c00;
  text-decoration: line-through;
}

.diff-added {
  background-color: #efe;
  color: #060;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 1.875rem;
  }
  
  .site-header nav {
    gap: 1rem;
  }
  
  .site-header nav a {
    font-size: 0.875rem;
  }
  
  .categories-grid,
  .tools-grid {
    grid-template-columns: 1fr;
  }
  
  .tool-panel {
    padding: 1rem;
  }
  
  .btn-group {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
  }
  
  .site-footer .container {
    flex-direction: column;
    text-align: center;
  }
  
  /* Text compare responsive */
  .diff-container {
    grid-template-columns: 1fr;
  }
}

/* ===== Accessibility ===== */
:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

.text-center {
  text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }