/* ==========================================================================
   AI Background Remover - Global Stylesheet (style.css)
   Pure Modern CSS3 Design System with CSS Variables, Light/Dark Modes & SEO Speed
   ========================================================================== */

:root {
  /* Brand Accents */
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-light: #eef2ff;
  --primary-glow: rgba(79, 70, 229, 0.18);
  
  --secondary: #0ea5e9;
  --secondary-hover: #0284c7;
  
  --success: #10b981;
  --success-bg: #ecfdf5;
  --warning: #f59e0b;
  --warning-bg: #fffbeb;
  --danger: #ef4444;
  --danger-bg: #fef2f2;
  
  /* Light Theme (Default) */
  --bg-body: #f8fafc;
  --bg-surface: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-card: #ffffff;
  --bg-card-hover: #f8fafc;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-inverse: #ffffff;
  
  --border-subtle: #e2e8f0;
  --border-strong: #cbd5e1;
  --border-focus: #4f46e5;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
  
  --checkerboard-1: #ffffff;
  --checkerboard-2: #e2e8f0;
  
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;
  
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  
  --header-height: 70px;
  --max-width: 1240px;
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-body: #090d16;
  --bg-surface: #0f172a;
  --bg-subtle: #1e293b;
  --bg-card: #131d31;
  --bg-card-hover: #1e293b;
  
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-inverse: #0f172a;
  
  --border-subtle: #1e293b;
  --border-strong: #334155;
  --border-focus: #818cf8;
  
  --primary-light: rgba(99, 102, 241, 0.15);
  --primary-glow: rgba(99, 102, 241, 0.3);
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.6);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.7);
  
  --checkerboard-1: #1e293b;
  --checkerboard-2: #0f172a;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.65;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

img, svg, video, canvas {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--primary-hover);
}

button, input, select, textarea {
  font: inherit;
}

/* Typography Hierarchy */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 4vw + 1rem, 3.25rem); margin-bottom: 1rem; }
h2 { font-size: clamp(1.5rem, 2.5vw + 0.75rem, 2.25rem); margin-top: 2rem; margin-bottom: 0.85rem; }
h3 { font-size: clamp(1.2rem, 1.5vw + 0.5rem, 1.5rem); margin-top: 1.5rem; margin-bottom: 0.5rem; }
p { margin-bottom: 1.2rem; color: var(--text-secondary); }

/* Layout Containers */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.container-sm {
  max-width: 860px;
}

.section {
  padding-top: 4rem;
  padding-bottom: 4rem;
}

.section-sm {
  padding-top: 2.5rem;
  padding-bottom: 2.5rem;
}

/* Header & Sticky Navbar */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

[data-theme="dark"] .site-header {
  background-color: rgba(15, 23, 42, 0.92);
}

.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--text-primary);
  text-decoration: none;
}

.brand-logo svg {
  color: var(--primary);
  width: 28px;
  height: 28px;
}

.brand-badge {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--primary-light);
  color: var(--primary);
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(79, 70, 229, 0.2);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
}

.nav-item {
  position: relative;
}

.nav-link {
  font-weight: 500;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.5rem 0.25rem;
  font-size: 0.95rem;
}

.nav-link:hover, .nav-link.active {
  color: var(--primary);
}

/* Nav Dropdown Menu */
.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 260px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xl);
  padding: 0.75rem;
  list-style: none;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all var(--transition-fast);
  z-index: 100;
}

.nav-item:hover .dropdown-menu,
.nav-item:focus-within .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-item a {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.65rem 0.75rem;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  transition: background-color var(--transition-fast);
}

.dropdown-item a:hover {
  background-color: var(--bg-subtle);
  color: var(--primary);
}

.dropdown-item-title {
  font-weight: 600;
  font-size: 0.9rem;
}

.dropdown-item-desc {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

/* Header Action Buttons */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

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

.theme-toggle-btn:hover {
  background: var(--border-subtle);
  color: var(--primary);
}

.theme-toggle-btn svg {
  width: 20px;
  height: 20px;
}

.mobile-menu-toggle {
  display: none;
  background: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

/* Mobile Navigation Drawer */
.mobile-nav-drawer {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg-surface);
  z-index: 999;
  padding: 1.5rem;
  transform: translateX(100%);
  transition: transform var(--transition-normal);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.mobile-nav-drawer.open {
  transform: translateX(0);
}

.mobile-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.mobile-nav-link {
  display: block;
  font-size: 1.1rem;
  font-weight: 600;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  color: var(--text-primary);
  background: var(--bg-subtle);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.65rem 1.35rem;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 4px rgba(79, 70, 229, 0.3);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  color: #ffffff;
  box-shadow: 0 4px 10px rgba(79, 70, 229, 0.4);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--bg-surface);
  color: var(--text-primary);
  border-color: var(--border-strong);
}

.btn-secondary:hover {
  background-color: var(--bg-subtle);
  color: var(--primary);
  border-color: var(--primary);
}

.btn-sm {
  padding: 0.4rem 0.85rem;
  font-size: 0.85rem;
  min-height: 36px;
}

.btn-lg {
  padding: 0.9rem 2rem;
  font-size: 1.05rem;
  min-height: 48px;
}

.btn-full {
  width: 100%;
}

/* Hero Section */
.hero-section {
  padding-top: 3.5rem;
  padding-bottom: 3.5rem;
  text-align: center;
  position: relative;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid rgba(79, 70, 229, 0.2);
  padding: 0.35rem 0.85rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 740px;
  margin: 0 auto 2rem auto;
}

.privacy-trust-tag {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: 1rem;
}

.privacy-trust-tag svg {
  color: var(--success);
  width: 16px;
  height: 16px;
}

/* Feature & Benefit Grid */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.75rem;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(380px, 1fr));
  gap: 2rem;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--border-strong);
}

.feature-icon-wrapper {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
}

.feature-icon-wrapper svg {
  width: 24px;
  height: 24px;
}

/* Interactive Before / After Demo Component */
.compare-demo-container {
  position: relative;
  width: 100%;
  max-width: 720px;
  margin: 2rem auto;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--border-subtle);
  aspect-ratio: 16 / 10;
  user-select: none;
  background-color: var(--bg-surface);
}

.compare-img-after {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    linear-gradient(45deg, var(--checkerboard-2) 25%, transparent 25%), 
    linear-gradient(-45deg, var(--checkerboard-2) 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, var(--checkerboard-2) 75%), 
    linear-gradient(-45deg, transparent 75%, var(--checkerboard-2) 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
  background-color: var(--checkerboard-1);
}

.compare-img-after img,
.compare-img-before img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.compare-img-before {
  position: absolute;
  top: 0;
  left: 0;
  width: 50%;
  height: 100%;
  overflow: hidden;
  border-right: 2px solid #ffffff;
}

.compare-slider-handle {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: #ffffff;
  cursor: ew-resize;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 20;
}

.compare-handle-btn {
  width: 36px;
  height: 36px;
  background: #ffffff;
  color: var(--primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
}

/* Comparison Table */
.table-wrapper {
  width: 100%;
  overflow-x: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
  background: var(--bg-surface);
  margin: 2rem 0;
  box-shadow: var(--shadow-sm);
}

.seo-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
}

.seo-table th, .seo-table td {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
}

.seo-table th {
  background: var(--bg-subtle);
  font-weight: 700;
  color: var(--text-primary);
}

.seo-table tr:last-child td {
  border-bottom: none;
}

.seo-table tr:hover td {
  background: rgba(79, 70, 229, 0.03);
}

.badge-check {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--success);
  font-weight: 600;
}

.badge-cross {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--danger);
  font-weight: 500;
}

/* Step-by-Step Flow */
.steps-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  margin-top: 2.5rem;
  position: relative;
}

.step-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem;
  position: relative;
}

.step-badge {
  width: 38px;
  height: 38px;
  background: var(--primary);
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 1.25rem;
  box-shadow: 0 4px 10px rgba(79, 70, 229, 0.3);
}

/* Accordion FAQ */
.faq-accordion {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 860px;
  margin: 2rem auto;
}

.faq-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-item:hover {
  border-color: var(--border-strong);
}

.faq-item.active {
  border-color: var(--primary);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  background: none;
  border: none;
  text-align: left;
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--text-primary);
  cursor: pointer;
}

.faq-icon {
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
  color: var(--primary);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0, 1, 0, 1);
  padding: 0 1.5rem;
}

.faq-item.active .faq-answer {
  max-height: 800px;
  padding-bottom: 1.25rem;
}

/* Breadcrumbs */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.breadcrumb a {
  color: var(--text-muted);
}

.breadcrumb a:hover {
  color: var(--primary);
}

.breadcrumb-separator {
  color: var(--border-strong);
}

/* Rich SEO Article Layout */
.seo-article {
  max-width: 860px;
  margin: 0 auto;
  line-height: 1.8;
  font-size: 1.05rem;
}

.seo-article h2 {
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 0.5rem;
  margin-top: 3rem;
}

.seo-article ul, .seo-article ol {
  margin: 1rem 0 1.5rem 1.5rem;
  color: var(--text-secondary);
}

.seo-article li {
  margin-bottom: 0.5rem;
}

.callout-box {
  background: var(--primary-light);
  border-left: 4px solid var(--primary);
  padding: 1.25rem 1.5rem;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: 1.75rem 0;
}

.callout-box p:last-child {
  margin-bottom: 0;
}

/* Footer */
.site-footer {
  margin-top: auto;
  background: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  padding: 4rem 0 2rem 0;
  font-size: 0.925rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 3rem;
}

.footer-brand p {
  margin-top: 0.75rem;
  color: var(--text-muted);
  max-width: 320px;
  font-size: 0.9rem;
}

.footer-title {
  font-size: 0.95rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  margin-bottom: 1.2rem;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.footer-links a {
  color: var(--text-muted);
}

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

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 2rem;
  border-top: 1px solid var(--border-subtle);
  color: var(--text-muted);
  font-size: 0.85rem;
  flex-wrap: wrap;
  gap: 1rem;
}

/* Form Styles */
.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.4rem;
  color: var(--text-primary);
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-strong);
  background: var(--bg-surface);
  color: var(--text-primary);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-control:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--primary-glow);
}

textarea.form-control {
  min-height: 120px;
  resize: vertical;
}

/* Responsive Media Queries */
@media (max-width: 992px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  .nav-links, .nav-actions .btn-primary {
    display: none;
  }
  
  .mobile-menu-toggle {
    display: flex;
  }
  
  .hero-section {
    padding-top: 2.5rem;
    padding-bottom: 2.5rem;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-bottom {
    flex-direction: column;
    text-align: center;
    justify-content: center;
  }
}