/* ==========================================================================
   UNIT CONVERTER - STYLESHEET (style.css)
   Clean, modern, responsive design system with CSS custom properties,
   dark mode, custom theme accent color, glassmorphic cards, smooth transitions,
   media compressor tools (Image & Video), 45+ Converter Tabs, and SEO FAQ Accordion.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Custom Variables & Root Design System
   -------------------------------------------------------------------------- */
:root {
  /* Brand Accent Color (Customizable dynamically via Color Picker) */
  --primary-accent: #3b82f6;
  --primary-accent-hover: #2563eb;
  --primary-accent-light: rgba(59, 130, 246, 0.12);
  --primary-accent-glow: rgba(59, 130, 246, 0.25);
  
  /* Standard Light Theme Tokens */
  --bg-main: #f8fafc;
  --bg-gradient: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);
  --surface-card: #ffffff;
  --surface-card-subtle: #f1f5f9;
  --border-color: #e2e8f0;
  --border-focus: var(--primary-accent);
  
  /* Text Colors */
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-subtle: #94a3b8;
  
  /* Feedback / Badges */
  --success-color: #10b981;
  --danger-color: #ef4444;
  --warning-color: #f59e0b;
  
  /* Shadows & Radius */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
  --shadow-glow: 0 0 20px var(--primary-accent-glow);
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s ease;
  
  /* Fonts */
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
}

/* Dark Theme Overrides */
[data-theme="dark"] {
  --bg-main: #0b0f19;
  --bg-gradient: linear-gradient(135deg, #0b0f19 0%, #111827 100%);
  --surface-card: #1e293b;
  --surface-card-subtle: #0f172a;
  --border-color: #334155;
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-subtle: #64748b;
  
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.4);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text-main);
  min-height: 100vh;
  line-height: 1.6;
}

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.margin-bottom-2 {
  margin-bottom: 2rem;
}

/* Header Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: background var(--transition-normal);
}

[data-theme="dark"] .navbar {
  background: rgba(30, 41, 59, 0.85);
}

.nav-container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0.85rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
}

.logo-icon {
  width: 42px;
  height: 42px;
  background: var(--primary-accent);
  color: #ffffff;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: 0 4px 12px var(--primary-accent-glow);
  transition: transform var(--transition-fast);
}

.logo:hover .logo-icon {
  transform: rotate(180deg);
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.2rem;
  line-height: 1.2;
}

.brand-highlight {
  color: var(--primary-accent);
}

.brand-subtitle {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.nav-link {
  padding: 0.45rem 0.75rem;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.accent-picker-wrapper {
  position: relative;
  width: 38px;
  height: 38px;
}

.accent-picker-btn {
  width: 100%;
  height: 100%;
  border-radius: var(--radius-full);
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  color: var(--primary-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1rem;
}

#accent-color-picker {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

.theme-toggle-btn {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

.sun-icon { display: none; }
.moon-icon { display: inline-block; }

[data-theme="dark"] .sun-icon { display: inline-block; color: #f59e0b; }
[data-theme="dark"] .moon-icon { display: none; }

/* Hero Section */
.hero-section {
  padding: 3rem 1.25rem 1.5rem 1.25rem;
  text-align: center;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.85rem;
  background: var(--primary-accent-light);
  color: var(--primary-accent);
  border-radius: var(--radius-full);
  font-size: 0.825rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: 2.6rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.2;
  margin-bottom: 0.75rem;
}

.hero-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 780px;
  margin: 0 auto;
}

/* Search Bar & Group Filter Navigation Tabs */
.categories-section {
  margin-top: 1.5rem;
  margin-bottom: 2rem;
}

.section-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.section-header-row h2 {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.section-header-row .subtext {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.category-search-box {
  position: relative;
  min-width: 320px;
}

.category-search-box input {
  width: 100%;
  padding: 0.65rem 1rem 0.65rem 2.4rem;
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--text-main);
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  outline: none;
  transition: all var(--transition-fast);
}

.category-search-box input:focus {
  border-color: var(--primary-accent);
  box-shadow: 0 0 0 3px var(--primary-accent-light);
}

.search-icon {
  position: absolute;
  left: 0.9rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 0.85rem;
}

.group-tabs-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  overflow-x: auto;
  padding-bottom: 0.75rem;
  margin-bottom: 1rem;
  scrollbar-width: thin;
}

.group-tab {
  padding: 0.45rem 1rem;
  border-radius: var(--radius-full);
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 0.825rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.group-tab:hover {
  border-color: var(--primary-accent);
  color: var(--primary-accent);
}

.group-tab.active {
  background: var(--primary-accent);
  border-color: var(--primary-accent);
  color: #ffffff;
  box-shadow: 0 4px 12px var(--primary-accent-glow);
}

.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
  gap: 0.75rem;
  max-height: 420px;
  overflow-y: auto;
  padding-right: 0.25rem;
  scrollbar-width: thin;
}

.category-btn {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.85rem 0.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  color: var(--text-muted);
  text-align: center;
}

.category-btn i {
  font-size: 1.25rem;
}

.category-btn span {
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1.2;
}

.category-btn:hover {
  transform: translateY(-2px);
  border-color: var(--primary-accent);
  color: var(--primary-accent);
  box-shadow: var(--shadow-md);
}

.category-btn.active {
  background: var(--primary-accent);
  border-color: var(--primary-accent);
  color: #ffffff;
  box-shadow: 0 4px 14px var(--primary-accent-glow);
}

/* Main Converter Card */
.converter-section {
  margin-bottom: 2.5rem;
}

.converter-card {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.converter-card-header {
  padding: 1.5rem 1.75rem;
  background: var(--surface-card-subtle);
  border-bottom: 1px solid var(--border-color);
}

.category-info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.category-icon {
  width: 48px;
  height: 48px;
  background: var(--primary-accent-light);
  color: var(--primary-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.category-info h3 {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.2;
}

.category-info p {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.converter-body {
  padding: 2rem 1.75rem;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1.5rem;
  align-items: start;
}

.unit-box {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.input-label {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
}

.input-group {
  position: relative;
  display: flex;
  align-items: center;
}

.unit-input {
  width: 100%;
  padding: 0.9rem 2.5rem 0.9rem 1rem;
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-main);
  background: var(--surface-card-subtle);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  outline: none;
}

.unit-input:focus {
  border-color: var(--primary-accent);
  background: var(--surface-card);
}

.clear-input-btn {
  position: absolute;
  right: 0.9rem;
  color: var(--text-subtle);
  cursor: pointer;
  font-size: 1.1rem;
}

.select-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.unit-select {
  width: 100%;
  padding: 0.85rem 2.25rem 0.85rem 1rem;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-main);
  background: var(--surface-card-subtle);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  outline: none;
  cursor: pointer;
  appearance: none;
}

.select-arrow {
  position: absolute;
  right: 1rem;
  pointer-events: none;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.unit-description-card {
  background: var(--primary-accent-light);
  border-left: 3px solid var(--primary-accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 0.75rem 0.9rem;
  display: flex;
  gap: 0.6rem;
  align-items: flex-start;
  margin-top: 0.25rem;
}

.desc-icon {
  color: var(--primary-accent);
  font-size: 1rem;
  margin-top: 0.15rem;
  flex-shrink: 0;
}

.desc-text {
  font-size: 0.825rem;
  color: var(--text-main);
  line-height: 1.45;
}

.swap-box {
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 2rem;
}

.swap-btn {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  background: var(--surface-card);
  border: 2px solid var(--border-color);
  color: var(--primary-accent);
  font-size: 1.2rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-fast);
}

.swap-btn:hover {
  background: var(--primary-accent);
  color: #ffffff;
  border-color: var(--primary-accent);
  transform: rotate(180deg) scale(1.1);
}

.result-display-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.result-display {
  width: 100%;
  padding: 0.9rem 3rem 0.9rem 1rem;
  background: var(--primary-accent-light);
  border: 2px solid var(--primary-accent);
  border-radius: var(--radius-md);
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-accent);
  word-break: break-all;
  min-height: 58px;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.copy-btn {
  position: absolute;
  right: 0.75rem;
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

.converter-footer {
  padding: 1rem 1.75rem;
  background: var(--surface-card-subtle);
  border-top: 1px solid var(--border-color);
}

.formula-info {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
}

/* Special Tools Section */
.special-tools-section {
  margin-bottom: 2.5rem;
}

.case-converter-grid {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.tool-textarea {
  width: 100%;
  padding: 1rem;
  font-family: var(--font-body);
  font-size: 0.95rem;
  color: var(--text-main);
  background: var(--surface-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  outline: none;
  resize: vertical;
}

.case-buttons-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.case-btn {
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-sm);
  background: var(--surface-card-subtle);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  font-size: 0.825rem;
  font-weight: 600;
  cursor: pointer;
}

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

.bases-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.25rem;
}

.base-input-row {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.base-input-row label {
  font-size: 0.825rem;
  font-weight: 700;
  color: var(--text-muted);
}

/* SEO Accordion FAQ Section */
.faq-section {
  margin-bottom: 2.5rem;
}

.faq-card {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-lg);
}

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

.faq-header h2 {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.faq-accordion {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

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

.faq-question {
  width: 100%;
  padding: 1rem 1.25rem;
  background: transparent;
  border: none;
  color: var(--text-main);
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  text-align: left;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.faq-arrow {
  font-size: 0.85rem;
  color: var(--primary-accent);
  transition: transform var(--transition-fast);
}

.faq-item.active .faq-arrow {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 1.25rem 1rem 1.25rem;
  display: none;
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.faq-item.active .faq-answer {
  display: block;
}

/* Media Tool Cards & Compressor Dropzones */
.media-tool-section {
  margin-bottom: 2.5rem;
}

.tool-card {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.tool-card-header {
  padding: 1.5rem 1.75rem;
  background: var(--surface-card-subtle);
  border-bottom: 1px solid var(--border-color);
}

.tool-title-group {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.tool-icon-box {
  width: 48px;
  height: 48px;
  background: var(--primary-accent-light);
  color: var(--primary-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.tool-title-group h2 {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
}

.tool-title-group p {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.tool-card-body {
  padding: 2rem 1.75rem;
}

.file-dropzone {
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-md);
  padding: 3rem 1.5rem;
  text-align: center;
  background: var(--surface-card-subtle);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.dropzone-icon {
  font-size: 3rem;
  color: var(--primary-accent);
  margin-bottom: 0.5rem;
}

.file-input-hidden { display: none; }

.browse-btn {
  background: var(--primary-accent);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-full);
  padding: 0.6rem 1.5rem;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  margin-top: 0.75rem;
}

.media-workspace {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.controls-panel {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)) auto;
  gap: 1.25rem;
  align-items: end;
  background: var(--surface-card-subtle);
  padding: 1.25rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.control-group label {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-main);
}

.tool-slider {
  width: 100%;
  accent-color: var(--primary-accent);
  cursor: pointer;
}

.tool-select {
  width: 100%;
  padding: 0.6rem 0.9rem;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-main);
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  outline: none;
}

.action-btn {
  background: var(--primary-accent);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.75rem 1.25rem;
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.preview-comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.preview-card {
  background: var(--surface-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.preview-card-header {
  padding: 0.75rem 1rem;
  background: var(--surface-card);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 700;
  font-size: 0.875rem;
}

.file-badge {
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-full);
  font-size: 0.775rem;
}

.badge-neutral { background: var(--border-color); color: var(--text-main); }
.badge-success { background: rgba(16, 185, 129, 0.15); color: var(--success-color); }

.preview-img-wrapper {
  padding: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 220px;
  max-height: 320px;
  background: #00000010;
}

.preview-img-wrapper img {
  max-width: 100%;
  max-height: 280px;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.preview-card-footer {
  padding: 0.75rem 1rem;
  background: var(--surface-card);
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
}

.savings-badge {
  background: rgba(16, 185, 129, 0.15);
  color: var(--success-color);
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 0.8rem;
}

.download-btn {
  background: var(--success-color);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.5rem 1rem;
  font-weight: 700;
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* Popular Grid */
.popular-conversions {
  margin-bottom: 2.5rem;
}

.popular-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.85rem;
}

.popular-card {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.85rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  cursor: pointer;
}

.popular-card i {
  color: var(--primary-accent);
  font-size: 1.1rem;
}

.popular-card span {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-main);
}

/* Color Picker */
.color-section {
  margin-bottom: 2.5rem;
}

.color-card {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.color-card-header {
  padding: 1.5rem 1.75rem;
  background: var(--surface-card-subtle);
  border-bottom: 1px solid var(--border-color);
}

.color-card-body {
  padding: 2rem 1.75rem;
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 2rem;
  align-items: start;
}

.color-picker-left {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.color-preview-box {
  width: 100%;
  height: 180px;
  border-radius: var(--radius-md);
  background: #3b82f6;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  overflow: hidden;
}

.color-hex-badge {
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  color: #ffffff;
  padding: 0.35rem 0.85rem;
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
}

.pick-color-trigger {
  background: rgba(255, 255, 255, 0.9);
  color: #0f172a;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
}

.preset-palette {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.palette-title {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
}

.palette-swatches {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.swatch {
  width: 26px;
  height: 26px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.color-picker-right {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.color-format-row {
  display: grid;
  grid-template-columns: 100px 1fr;
  align-items: center;
  gap: 1rem;
}

.color-format-row label {
  font-weight: 700;
  font-size: 0.9rem;
}

.input-with-copy {
  position: relative;
  display: flex;
  align-items: center;
}

.input-with-copy input {
  width: 100%;
  padding: 0.75rem 2.75rem 0.75rem 1rem;
  font-family: monospace;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-main);
  background: var(--surface-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  outline: none;
}

.copy-code-btn {
  position: absolute;
  right: 0.5rem;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* History Section */
.history-section {
  margin-bottom: 2.5rem;
}

.history-card {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 1.75rem;
}

.history-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.clear-btn {
  background: rgba(239, 68, 68, 0.1);
  color: var(--danger-color);
  border: 1px solid rgba(239, 68, 68, 0.2);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.9rem;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}

.history-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.history-item {
  background: var(--surface-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.85rem 1.1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  cursor: pointer;
}

.empty-history-msg {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

/* Footer */
.footer {
  background: var(--surface-card);
  border-top: 1px solid var(--border-color);
  padding: 1.75rem 0;
  margin-top: 2rem;
}

.footer-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
}

/* Toast */
.toast-container {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toast {
  background: var(--text-main);
  color: var(--surface-card);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  animation: slideIn 0.3s ease, fadeOut 0.3s ease 2.7s forwards;
}

@keyframes slideIn {
  from { transform: translateY(20px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

@keyframes fadeOut {
  from { opacity: 1; }
  to { opacity: 0; transform: translateY(-10px); }
}

/* Responsive */
@media (max-width: 900px) {
  .converter-body { grid-template-columns: 1fr; }
  .swap-box { padding-top: 0; margin: -0.5rem 0; }
  .swap-btn { transform: rotate(90deg); }
  .color-card-body { grid-template-columns: 1fr; }
  .preview-comparison-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .hero-title { font-size: 2.1rem; }
  .nav-links { display: none; }
  .section-header-row { flex-direction: column; align-items: stretch; }
  .category-search-box { min-width: 100%; }
}