/* ==========================================================================
   MicroKit Design System - Shared Styles
   Version: 1.0.0
   ========================================================================== */

/* ---- CSS Custom Properties (Design Tokens) ---- */
:root {
  /* Color Palette - Light Mode */
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #dbeafe;
  --color-secondary: #0f172a;
  --color-secondary-hover: #1e293b;
  --color-accent: #0ea5e9;
  --color-success: #16a34a;
  --color-warning: #f59e0b;
  --color-error: #dc2626;

  --color-bg: #ffffff;
  --color-bg-secondary: #f8fafc;
  --color-bg-tertiary: #f1f5f9;
  --color-surface: #ffffff;
  --color-surface-hover: #f8fafc;
  --color-border: #e2e8f0;
  --color-border-strong: #cbd5e1;

  --color-text-primary: #0f172a;
  --color-text-secondary: #475569;
  --color-text-tertiary: #94a3b8;
  --color-text-inverse: #ffffff;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Spacing Scale */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  --line-height-tight: 1.1;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;

  /* Layout */
  --container-max: 1200px;
  --header-height: 64px;
  --footer-height: auto;

  /* Z-index Scale */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 400;
  --z-modal: 500;
  --z-popover: 600;
  --z-tooltip: 700;
}

/* Dark Mode */
[data-theme="dark"] {
  --color-primary: #3b82f6;
  --color-primary-hover: #60a5fa;
  --color-primary-light: #1e3a5f;
  --color-secondary: #f8fafc;
  --color-secondary-hover: #e2e8f0;
  --color-accent: #38bdf8;
  --color-success: #22c55e;
  --color-warning: #fbbf24;
  --color-error: #ef4444;

  --color-bg: #0f172a;
  --color-bg-secondary: #1e293b;
  --color-bg-tertiary: #334155;
  --color-surface: #1e293b;
  --color-surface-hover: #334155;
  --color-border: #334155;
  --color-border-strong: #475569;

  --color-text-primary: #f8fafc;
  --color-text-secondary: #cbd5e1;
  --color-text-tertiary: #94a3b8;
  --color-text-inverse: #0f172a;
}

/* ---- Reset & Base ---- */
*, *::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);
  font-size: var(--text-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

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

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

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ---- Typography ---- */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-text-primary);
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p {
  margin-bottom: var(--space-4);
  color: var(--color-text-secondary);
}

.lead {
  font-size: var(--text-lg);
  color: var(--color-text-primary);
  font-weight: var(--font-weight-medium);
}

.text-muted {
  color: var(--color-text-tertiary);
  font-size: var(--text-sm);
}

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

/* ---- Container ---- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

@media (min-width: 640px) {
  .container { padding: 0 var(--space-6); }
}

@media (min-width: 1024px) {
  .container { padding: 0 var(--space-8); }
}

/* ---- Header / Navbar ---- */
.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  height: var(--header-height);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(8px);
  background-color: rgba(var(--color-surface), 0.9);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: var(--space-4);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  text-decoration: none;
}

.logo:hover { color: var(--color-text-primary); }

.logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-inverse);
  font-weight: var(--font-weight-bold);
  font-size: var(--text-sm);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.nav-link:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-primary);
}

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

.nav-divider {
  width: 1px;
  height: 24px;
  background-color: var(--color-border);
  margin: 0 var(--space-2);
}

/* ---- Theme Toggle ---- */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background-color: var(--color-surface);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--color-bg-tertiary);
  border-color: var(--color-border-strong);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
  transition: transform var(--transition-normal), opacity var(--transition-normal);
}

[data-theme="light"] .sun-icon { display: block; }
[data-theme="light"] .moon-icon { display: none; }
[data-theme="dark"] .sun-icon { display: none; }
[data-theme="dark"] .moon-icon { display: block; }

/* ---- Language Switcher ---- */
.lang-switcher {
  position: relative;
}

.lang-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background-color: var(--color-surface);
  color: var(--color-text-primary);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.lang-btn:hover {
  background-color: var(--color-bg-tertiary);
  border-color: var(--color-border-strong);
}

.lang-btn svg { width: 16px; height: 16px; }

.lang-dropdown {
  position: absolute;
  top: calc(100% + var(--space-2));
  right: 0;
  min-width: 140px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: var(--space-2);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all var(--transition-fast);
  z-index: var(--z-dropdown);
}

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

.lang-option {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-2) var(--space-3);
  border: none;
  border-radius: var(--radius-sm);
  background: none;
  color: var(--color-text-primary);
  font-size: var(--text-sm);
  text-align: left;
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.lang-option:hover {
  background-color: var(--color-bg-tertiary);
}

.lang-option.active {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

/* ---- Mobile Menu ---- */
.mobile-menu-btn {
  display: none;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: none;
  background: none;
  color: var(--color-text-primary);
  cursor: pointer;
}

.mobile-menu-btn svg { width: 24px; height: 24px; }

@media (max-width: 768px) {
  .mobile-menu-btn { display: flex; }

  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: var(--space-4);
    gap: var(--space-2);
    box-shadow: var(--shadow-lg);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
  }

  .nav.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-link { width: 100%; justify-content: center; }
  .nav-divider { display: none; }
}

/* ---- Hero Section ---- */
.hero {
  padding: var(--space-16) 0;
  text-align: center;
}

.hero h1 {
  margin-bottom: var(--space-4);
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.hero .lead {
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: var(--space-8);
}

.hero-actions {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-semibold);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
  text-decoration: none;
  white-space: nowrap;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-primary);
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  color: var(--color-text-inverse);
}

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

.btn-secondary:hover:not(:disabled) {
  background-color: var(--color-bg-tertiary);
  border-color: var(--color-border-strong);
}

.btn-ghost {
  background-color: transparent;
  color: var(--color-text-secondary);
  border-color: transparent;
}

.btn-ghost:hover:not(:disabled) {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-primary);
}

.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-xs);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

.btn-icon { width: 18px; height: 18px; }

/* ---- Tool Grid ---- */
.tools-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

@media (min-width: 480px) {
  .tools-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 768px) {
  .tools-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (min-width: 1024px) {
  .tools-grid { grid-template-columns: repeat(4, 1fr); }
}

/* ---- Tool Card ---- */
.tool-card {
  display: flex;
  flex-direction: column;
  padding: var(--space-6);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  transition: all var(--transition-normal);
  min-height: 200px;
}

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

.tool-card:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.tool-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-4);
}

.tool-icon svg {
  width: 24px;
  height: 24px;
  color: var(--color-text-inverse);
}

.tool-card h3 {
  font-size: var(--text-lg);
  margin-bottom: var(--space-2);
  color: var(--color-text-primary);
}

.tool-card p {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin: 0;
  flex-grow: 1;
}

/* ---- Search & Filter ---- */
.search-filter {
  margin-bottom: var(--space-8);
}

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

.search-wrapper svg {
  position: absolute;
  left: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--color-text-tertiary);
}

.search-input {
  width: 100%;
  padding: var(--space-3) var(--space-3) var(--space-3) var(--space-10);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  color: var(--color-text-primary);
  font-size: var(--text-base);
  transition: all var(--transition-fast);
}

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

.search-input::placeholder {
  color: var(--color-text-tertiary);
}

.filter-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.filter-tag {
  padding: var(--space-1) var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background-color: var(--color-surface);
  color: var(--color-text-secondary);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-medium);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-tag:hover,
.filter-tag.active {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* ---- Section ---- */
.section {
  padding: var(--space-12) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-10);
}

.section-header h2 {
  margin-bottom: var(--space-3);
}

.section-header p {
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ---- Ad Slots (CLS-safe) ---- */
.ad-slot {
  width: 100%;
  min-height: 90px;
  background-color: var(--color-bg-tertiary);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-tertiary);
  font-size: var(--text-sm);
  margin: var(--space-8) 0;
  overflow: hidden;
  position: relative;
}

.ad-slot.ad-top { min-height: 100px; }
.ad-slot.ad-bottom { min-height: 100px; }
.ad-slot.ad-sidebar { min-height: 250px; }

.ad-label {
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: var(--font-weight-medium);
}

.ad-slot ins {
  display: block;
  width: 100%;
  height: 100%;
}

/* ---- Tool Page Layout ---- */
.tool-page {
  flex: 1;
  padding: var(--space-8) 0;
}

.tool-header {
  margin-bottom: var(--space-8);
}

.tool-header h1 {
  margin-bottom: var(--space-2);
}

.tool-header .lead {
  margin-bottom: 0;
}

.tool-main {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
}

@media (min-width: 1024px) {
  .tool-main {
    grid-template-columns: 1fr 320px;
    align-items: start;
  }
}

.tool-content { min-width: 0; }
.tool-sidebar { position: sticky; top: calc(var(--header-height) + var(--space-4)); }

/* ---- Tool Card (Interactive) ---- */
.tool-panel {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-bottom: var(--space-6);
}

.tool-panel h2 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--color-border);
}

.tool-panel h3 {
  font-size: var(--text-lg);
  margin: var(--space-4) 0 var(--space-2);
}

/* ---- Form Elements ---- */
.form-group {
  margin-bottom: var(--space-4);
}

.form-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  margin-bottom: var(--space-1);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-bg);
  color: var(--color-text-primary);
  font-size: var(--text-base);
  transition: all var(--transition-fast);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
  outline: none;
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--color-text-tertiary);
}

.form-select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='20' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-3) center;
  padding-right: var(--space-10);
}

.form-textarea {
  min-height: 120px;
  resize: vertical;
  font-family: var(--font-mono);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

@media (min-width: 640px) {
  .form-row { grid-template-columns: repeat(2, 1fr); }
}

.form-row-3 {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

@media (min-width: 768px) {
  .form-row-3 { grid-template-columns: repeat(3, 1fr); }
}

.input-group {
  display: flex;
  align-items: stretch;
}

.input-group .form-input { border-radius: var(--radius-md) 0 0 var(--radius-md); }
.input-group .btn { border-radius: 0 var(--radius-md) var(--radius-md) 0; }

.checkbox-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.checkbox-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  cursor: pointer;
}

.checkbox-item input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--color-primary);
  cursor: pointer;
}

.checkbox-item label {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  cursor: pointer;
}

/* ---- Result Display ---- */
.result-display {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  margin-top: var(--space-4);
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  text-align: center;
  color: var(--color-primary);
  font-weight: var(--font-weight-bold);
  min-height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  word-break: break-all;
}

.result-detail {
  font-size: var(--text-sm);
  font-weight: var(--font-weight-normal);
  color: var(--color-text-secondary);
  margin-top: var(--space-2);
  font-family: var(--font-sans);
  text-align: left;
}

/* ---- Tables ---- */
.table-wrapper {
  overflow-x: auto;
  margin: var(--space-4) 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.table th,
.table td {
  padding: var(--space-3);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.table th {
  background-color: var(--color-bg-secondary);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  white-space: nowrap;
}

.table tr:last-child td { border-bottom: none; }
.table tr:hover td { background-color: var(--color-bg-secondary); }

/* ---- Footer ---- */
.footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-12) 0 var(--space-6);
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  margin-bottom: var(--space-8);
}

@media (min-width: 768px) {
  .footer-grid { grid-template-columns: 2fr repeat(3, 1fr); }
}

.footer-brand .logo { margin-bottom: var(--space-4); }
.footer-brand p { color: var(--color-text-tertiary); font-size: var(--text-sm); max-width: 280px; }

.footer-column h4 {
  font-size: var(--text-sm);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-4);
}

.footer-column ul { list-style: none; }
.footer-column li { margin-bottom: var(--space-2); }
.footer-column a { color: var(--color-text-secondary); font-size: var(--text-sm); }
.footer-column a:hover { color: var(--color-primary); }

.footer-bottom {
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  text-align: center;
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
}

@media (min-width: 640px) {
  .footer-bottom { flex-direction: row; justify-content: space-between; }
}

.footer-links { display: flex; gap: var(--space-6); }
.footer-links a { color: var(--color-text-tertiary); }
.footer-links a:hover { color: var(--color-primary); }

/* ---- SEO Content Section ---- */
.seo-content {
  margin-top: var(--space-12);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
}

.seo-content h2 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-6);
}

.seo-content h3 {
  font-size: var(--text-lg);
  margin: var(--space-6) 0 var(--space-3);
}

.seo-content p { margin-bottom: var(--space-4); }
.seo-content ul { margin-left: var(--space-6); margin-bottom: var(--space-4); }
.seo-content li { margin-bottom: var(--space-2); color: var(--color-text-secondary); }

.faq {
  margin-top: var(--space-8);
}

.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-3);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4);
  background-color: var(--color-surface);
  border: none;
  color: var(--color-text-primary);
  font-size: var(--text-base);
  font-weight: var(--font-weight-medium);
  text-align: left;
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.faq-question:hover { background-color: var(--color-bg-tertiary); }

.faq-question svg {
  width: 20px;
  height: 20px;
  color: var(--color-text-tertiary);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
  margin-left: var(--space-4);
}

.faq-item.open .faq-question svg { transform: rotate(180deg); }

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal), padding var(--transition-normal);
}

.faq-item.open .faq-answer {
  max-height: 500px;
  padding: 0 var(--space-4) var(--space-4);
}

.faq-answer p { margin-bottom: var(--space-3); }
.faq-answer p:last-child { margin-bottom: 0; }

/* ---- Loading & Error States ---- */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: var(--space-8);
  color: var(--color-text-secondary);
}

.spinner {
  width: 24px;
  height: 24px;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

.error-message {
  background-color: #fef2f2;
  border: 1px solid #fecaca;
  color: #dc2626;
  padding: var(--space-4);
  border-radius: var(--radius-md);
  margin: var(--space-4) 0;
}

[data-theme="dark"] .error-message {
  background-color: #450a0a;
  border-color: #7f1d1d;
  color: #fca5a5;
}

.success-message {
  background-color: #f0fdf4;
  border: 1px solid #bbf7d0;
  color: #16a34a;
  padding: var(--space-4);
  border-radius: var(--radius-md);
  margin: var(--space-4) 0;
}

[data-theme="dark"] .success-message {
  background-color: #052e16;
  border-color: #14532d;
  color: #86efac;
}

/* ---- Utility Classes ---- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.hidden { display: none !important; }
.visible { display: block !important; }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }

.mt-4 { margin-top: var(--space-4); }
.mt-8 { margin-top: var(--space-8); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-8 { margin-bottom: var(--space-8); }

.w-full { width: 100%; }
.text-sm { font-size: var(--text-sm); }
.text-xs { font-size: var(--text-xs); }
.font-medium { font-weight: var(--font-weight-medium); }
.font-semibold { font-weight: var(--font-weight-semibold); }

/* ---- Print Styles ---- */
@media print {
  .header, .footer, .ad-slot, .theme-toggle, .lang-switcher, .btn, .search-filter { display: none !important; }
  .tool-page { padding: 0; }
  .tool-main { grid-template-columns: 1fr; }
  .tool-sidebar { display: none; }
  body { background: white; color: black; }
  .tool-panel { border: 1px solid #ccc; box-shadow: none; }
}