/* ============================================================
   main.css - Tools Website Stylesheet
   Design Language: Linear / Vercel / Stripe
   Modern, restrained, calm surface hierarchy, minimal chrome
   ============================================================ */

/* ----------------------------------------------------------
   1. CSS Custom Properties (Design Tokens)
   ---------------------------------------------------------- */
:root {
  /* --- Color Palette (Light Theme) --- */
  --color-primary: #2563EB;
  --color-primary-hover: #1D4ED8;
  --color-primary-light: #EFF6FF;
  --color-primary-dark: #1E40AF;

  --color-success: #10B981;
  --color-success-light: #D1FAE5;
  --color-warning: #F59E0B;
  --color-warning-light: #FEF3C7;
  --color-error: #EF4444;
  --color-error-light: #FEE2E2;
  --color-info: #06B6D4;
  --color-info-light: #CFFAFE;

  /* --- Background & Surface --- */
  --color-bg: #FAFAFA;
  --color-bg-secondary: #F8FAFC;
  --color-bg-tertiary: #F1F5F9;
  --color-surface: #FFFFFF;
  --color-surface-hover: #F8FAFC;

  /* --- Text --- */
  --color-text: #0F172A;
  --color-text-secondary: #64748B;
  --color-text-tertiary: #94A3B8;
  --color-text-inverse: #FFFFFF;
  --color-text-link: #2563EB;
  --color-text-link-hover: #1D4ED8;

  /* --- Border --- */
  --color-border: #E2E8F0;
  --color-border-light: #F1F5F9;
  --color-border-focus: #2563EB;

  /* --- Typography --- */
  --font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace;
  --font-size-xs: 0.6875rem;   /* 11px */
  --font-size-sm: 0.875rem;    /* 14px */
  --font-size-base: 1rem;      /* 16px */
  --font-size-md: 0.9375rem;   /* 15px */
  --font-size-lg: 1.125rem;    /* 18px */
  --font-size-xl: 1.25rem;     /* 20px */
  --font-size-2xl: 1.5rem;     /* 24px */
  --font-size-3xl: 2.25rem;    /* 36px */
  --font-size-4xl: 2.625rem;   /* 42px */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* --- Spacing --- */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */

  /* --- Border Radius --- */
  --radius-sm: 0.375rem;   /* 6px */
  --radius-md: 0.5rem;     /* 8px */
  --radius-lg: 0.75rem;    /* 12px */
  --radius-xl: 1rem;       /* 16px */
  --radius-full: 9999px;

  /* --- Shadows --- */
  --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, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.04);

  /* --- Layout --- */
  --nav-height: 56px;
  --sidebar-width: 240px;
  --container-max: 1280px;

  /* --- Transitions --- */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;

  /* --- Z-Index Scale --- */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-overlay: 300;
  --z-modal: 400;
  --z-toast: 500;
}


/* ----------------------------------------------------------
   2. Dark Theme (activated via html.dark)
   ---------------------------------------------------------- */
html.dark {
  --color-primary: #3B82F6;
  --color-primary-hover: #60A5FA;
  --color-primary-light: #1E293B;
  --color-primary-dark: #2563EB;

  --color-success: #34D399;
  --color-success-light: #064E3B;
  --color-warning: #FBBF24;
  --color-warning-light: #78350F;
  --color-error: #F87171;
  --color-error-light: #7F1D1D;
  --color-info: #22D3EE;
  --color-info-light: #164E63;

  --color-bg: #0B0F1A;
  --color-bg-secondary: #0F172A;
  --color-bg-tertiary: #1E293B;
  --color-surface: #111827;
  --color-surface-hover: #1E293B;

  --color-text: #F1F5F9;
  --color-text-secondary: #94A3B8;
  --color-text-tertiary: #64748B;
  --color-text-inverse: #0F172A;
  --color-text-link: #60A5FA;
  --color-text-link-hover: #93BBFD;

  --color-border: #1E293B;
  --color-border-light: #1E293B;
  --color-border-focus: #3B82F6;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
}


/* ----------------------------------------------------------
   3. Global Reset & Base Styles
   ---------------------------------------------------------- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

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

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

a:hover {
  color: var(--color-text-link-hover);
}

ul,
ol {
  list-style: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
  font-size: inherit;
}

input,
textarea,
select {
  font-family: inherit;
  font-size: inherit;
}

::selection {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* Scrollbar Styling */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-tertiary);
}


/* ----------------------------------------------------------
   4. Utility Classes
   ---------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

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

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

.flex {
  display: flex;
}

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

.justify-between {
  justify-content: space-between;
}

.gap-2 {
  gap: var(--space-2);
}

.gap-3 {
  gap: var(--space-3);
}

.gap-4 {
  gap: var(--space-4);
}

.gap-6 {
  gap: var(--space-6);
}


/* ----------------------------------------------------------
   5. Navigation Bar
   ---------------------------------------------------------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background-color: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-sticky);
}

html.dark .navbar {
  background-color: rgba(11, 15, 26, 0.72);
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
  gap: var(--space-4);
}

/* Logo */
.navbar-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  text-decoration: none;
  flex-shrink: 0;
  letter-spacing: -0.02em;
}

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

.navbar-logo svg,
.navbar-logo img {
  width: 28px;
  height: 28px;
}

/* Search */
.navbar-search {
  flex: 1;
  max-width: 420px;
  position: relative;
}

.search-input {
  width: 100%;
  height: 36px;
  padding: 0 var(--space-4) 0 36px;
  border: 1px solid transparent;
  border-radius: var(--radius-full);
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
  font-size: var(--font-size-sm);
  transition: all var(--transition-base);
  outline: none;
}

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

.search-input:hover {
  background-color: var(--color-bg-secondary);
}

.search-input:focus {
  border-color: var(--color-border-focus);
  background-color: var(--color-surface);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

html.dark .search-input:focus {
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

/* Search icon (positioned via parent) */
.navbar-search svg,
.navbar-search .search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 16px;
  height: 16px;
  color: var(--color-text-tertiary);
  pointer-events: none;
}

/* Nav Actions */
.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-shrink: 0;
}

/* Icon Button (40px circle) */
.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  position: relative;
}

.btn-icon:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
}

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

/* Language Label */
.lang-label {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  cursor: pointer;
}

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

.lang-label svg {
  width: 14px;
  height: 14px;
}

/* Hamburger Menu (mobile) */
.hamburger {
  display: none;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.hamburger:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
}

.hamburger svg {
  width: 22px;
  height: 22px;
}


/* ----------------------------------------------------------
   6. Main Layout
   ---------------------------------------------------------- */
.main-layout {
  display: flex;
  margin-top: var(--nav-height);
  min-height: calc(100vh - var(--nav-height));
}

.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  padding: var(--space-8) var(--space-6);
  max-width: 100%;
  min-width: 0;
}


/* ----------------------------------------------------------
   7. Sidebar
   ---------------------------------------------------------- */
.sidebar {
  position: fixed;
  top: var(--nav-height);
  left: 0;
  bottom: 0;
  width: var(--sidebar-width);
  background-color: var(--color-surface);
  border-right: 1px solid var(--color-border);
  overflow-y: auto;
  overflow-x: hidden;
  z-index: var(--z-dropdown);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-slow);
}

/* Sidebar Header */
.sidebar-header {
  flex-shrink: 0;
  padding: var(--space-4) var(--space-5);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-tertiary);
  border-bottom: 1px solid var(--color-border-light);
}

/* Sidebar List - 均分导航项 */
.sidebar-list {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 0;
  min-height: 0;
}

.sidebar-list li {
  flex: 1;
  display: flex;
  margin: 0;
}

.sidebar-list li a {
  flex: 1;
  width: 100%;
  display: flex;
  align-items: center;
}

/* Sidebar Item */
.sidebar-item {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: var(--space-3);
  width: 100%;
  height: 100%;
  min-height: 48px;
  padding: 0 var(--space-4);
  border-radius: 0;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  transition: background-color var(--transition-fast), color var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  cursor: pointer;
  box-sizing: border-box;
}

.sidebar-item:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
}

/* Active sidebar item */
.sidebar-item.active {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  font-weight: var(--font-weight-semibold);
}

.sidebar-item.active:hover {
  background-color: var(--color-primary-hover);
  color: var(--color-text-inverse);
}

/* Sidebar item icon */
.sidebar-item svg,
.sidebar-item img {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

/* Sidebar item count badge */
.sidebar-item .count {
  margin-left: auto;
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  background-color: var(--color-bg-tertiary);
  padding: 1px 7px;
  border-radius: var(--radius-full);
  font-weight: var(--font-weight-medium);
}

.sidebar-item.active .count {
  background-color: rgba(255, 255, 255, 0.2);
  color: var(--color-text-inverse);
}


/* ----------------------------------------------------------
   8. Sidebar Overlay (Mobile)
   ---------------------------------------------------------- */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.4);
  z-index: calc(var(--z-dropdown) - 1);
  opacity: 0;
  transition: opacity var(--transition-slow);
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}

.sidebar-overlay.visible {
  display: block;
  opacity: 1;
}


/* ----------------------------------------------------------
   9. Welcome / Hero Section
   ---------------------------------------------------------- */
.welcome-section {
  margin-bottom: var(--space-8);
  padding-bottom: var(--space-8);
  border-bottom: 1px solid var(--color-border-light);
}

.welcome-section h1,
.welcome-section .welcome-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  letter-spacing: -0.02em;
  line-height: var(--line-height-tight);
  margin-bottom: var(--space-3);
}

.welcome-section p,
.welcome-section .welcome-desc {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  max-width: 600px;
  margin-bottom: var(--space-2);
}


/* ----------------------------------------------------------
   10. Tools Grid
   ---------------------------------------------------------- */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-4);
}


/* ----------------------------------------------------------
   11. Tool Card
   ---------------------------------------------------------- */
.tool-card {
  position: relative;
  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);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
  text-decoration: none;
  color: inherit;
  overflow: hidden;
  cursor: pointer;
}

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

/* Tool Card Icon */
.tool-card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  margin-bottom: var(--space-4);
  transition: background-color var(--transition-base), color var(--transition-base);
  flex-shrink: 0;
}

.tool-card:hover .tool-card-icon {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.tool-card-icon svg,
.tool-card-icon img {
  width: 20px;
  height: 20px;
}

/* Tool Card Title */
.tool-card h3,
.tool-card .tool-card-title {
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-2);
  line-height: var(--line-height-tight);
  letter-spacing: -0.01em;
}

/* Tool Card Description */
.tool-card p,
.tool-card .tool-card-desc {
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.5;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* Tool Card Tag */
.tool-card-tag {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-secondary);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  margin-top: var(--space-3);
  align-self: flex-start;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.tool-card:hover .tool-card-tag {
  background-color: var(--color-bg-secondary);
}

/* Tool Card Arrow (optional, appears on hover) */
.tool-card .tool-card-arrow {
  position: absolute;
  top: var(--space-6);
  right: var(--space-6);
  width: 18px;
  height: 18px;
  color: var(--color-text-tertiary);
  opacity: 0;
  transform: translate(-4px, 4px);
  transition: all var(--transition-base);
}

.tool-card:hover .tool-card-arrow {
  opacity: 1;
  transform: translate(0, 0);
  color: var(--color-primary);
}


/* ----------------------------------------------------------
   12. Ad Slot
   ---------------------------------------------------------- */
.ad-slot {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  background-color: var(--color-bg-secondary);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-lg);
  color: var(--color-text-tertiary);
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  min-height: 100px;
  overflow: hidden;
  margin: var(--space-6) 0;
}

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


/* ----------------------------------------------------------
   13. Footer
   ---------------------------------------------------------- */
.footer {
  margin-left: var(--sidebar-width);
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: 0;
  margin-top: auto;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.footer-features {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-6);
  padding: var(--space-10) 0;
  border-bottom: 1px solid var(--color-border-light);
}

.footer-feature {
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
}

.footer-feature-icon {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-lg);
  background: var(--color-primary-alpha, rgba(37, 99, 235, 0.1));
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.footer-feature-icon svg {
  width: 20px;
  height: 20px;
}

.footer-feature h4 {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
  margin: 0 0 0.25rem;
}

.footer-feature p {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  margin: 0;
  line-height: 1.5;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-10);
  padding: var(--space-8) 0;
}

.footer-brand {
  max-width: 300px;
}

.footer-brand .logo {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  text-decoration: none;
  margin-bottom: var(--space-3);
}

.footer-brand .logo svg {
  width: 24px;
  height: 24px;
  color: var(--color-primary);
}

.footer-brand p {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  line-height: 1.6;
  margin: 0;
}

.footer-links-group {
  display: flex;
  gap: var(--space-10);
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-col h5 {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-secondary);
  margin: 0 0 var(--space-2);
}

.footer-col a {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-col a:hover {
  color: var(--color-text);
}

.footer-copyright {
  padding: var(--space-4) 0;
  border-top: 1px solid var(--color-border-light);
  text-align: center;
}

.footer-copyright p {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  margin: 0;
}


/* ----------------------------------------------------------
   14. Form Elements (shared across tool pages)
   ---------------------------------------------------------- */
.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface);
  color: var(--color-text);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-normal);
  transition: all var(--transition-fast);
  outline: none;
}

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

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

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

html.dark .form-input:focus,
html.dark .form-textarea:focus,
html.dark .form-select:focus {
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.form-textarea {
  resize: vertical;
  min-height: 100px;
}

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748B' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 40px;
  cursor: pointer;
}

.form-label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.form-group {
  margin-bottom: var(--space-5);
}

.form-hint {
  display: block;
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  margin-top: var(--space-1);
}

.form-error {
  display: block;
  font-size: var(--font-size-xs);
  color: var(--color-error);
  margin-top: var(--space-1);
}


/* ----------------------------------------------------------
   15. Buttons
   ---------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-lg);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-normal);
  transition: all var(--transition-fast);
  white-space: nowrap;
  cursor: pointer;
  border: 1px solid transparent;
  text-decoration: none;
}

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

/* Primary */
.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

/* Secondary */
.btn-secondary {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
  border-color: var(--color-border);
}

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

/* Outline */
.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

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

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

.btn-ghost:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
}

/* Danger */
.btn-danger {
  background-color: var(--color-error);
  color: var(--color-text-inverse);
}

.btn-danger:hover {
  background-color: #DC2626;
  box-shadow: var(--shadow-md);
}

/* Button Sizes */
.btn-sm {
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-xs);
  border-radius: var(--radius-md);
}

.btn-lg {
  padding: var(--space-4) var(--space-6);
  font-size: var(--font-size-base);
  border-radius: var(--radius-xl);
}

/* Button Group */
.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}


/* ----------------------------------------------------------
   16. Badge / Tag
   ---------------------------------------------------------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 2px 10px;
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  line-height: 1.5;
}

.badge-primary {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

.badge-success {
  background-color: var(--color-success-light);
  color: var(--color-success);
}

.badge-warning {
  background-color: var(--color-warning-light);
  color: var(--color-warning);
}

.badge-error {
  background-color: var(--color-error-light);
  color: var(--color-error);
}

.badge-neutral {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-secondary);
}


/* ----------------------------------------------------------
   17. Page Header
   ---------------------------------------------------------- */
.page-header {
  margin-bottom: var(--space-8);
}

.page-header h1,
.page-header .page-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: var(--space-3);
  line-height: var(--line-height-tight);
  letter-spacing: -0.02em;
}

.page-header p,
.page-header .page-desc {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  max-width: 640px;
  line-height: var(--line-height-relaxed);
}


/* ----------------------------------------------------------
   18. Empty State
   ---------------------------------------------------------- */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-16) var(--space-8);
  text-align: center;
}

.empty-state svg,
.empty-state .empty-icon {
  width: 64px;
  height: 64px;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-6);
}

.empty-state h3,
.empty-state .empty-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.empty-state p,
.empty-state .empty-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  max-width: 400px;
  margin-bottom: var(--space-6);
}


/* ----------------------------------------------------------
   19. Loading Skeleton
   ---------------------------------------------------------- */
.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-bg-tertiary) 25%,
    var(--color-border-light) 50%,
    var(--color-bg-tertiary) 75%
  );
  background-size: 200% 100%;
  animation: skeleton-loading 1.5s ease-in-out infinite;
  border-radius: var(--radius-md);
}

@keyframes skeleton-loading {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

.skeleton-text {
  height: 16px;
  margin-bottom: var(--space-2);
}

.skeleton-title {
  height: 24px;
  width: 60%;
  margin-bottom: var(--space-3);
}

.skeleton-card {
  height: 200px;
  border-radius: var(--radius-lg);
}


/* ----------------------------------------------------------
   20. Toast / Notification
   ---------------------------------------------------------- */
.toast {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  z-index: var(--z-toast);
  font-size: var(--font-size-sm);
  color: var(--color-text);
  animation: toast-in 0.3s ease;
}

.toast-success { border-left: 4px solid var(--color-success); }
.toast-error { border-left: 4px solid var(--color-error); }
.toast-warning { border-left: 4px solid var(--color-warning); }
.toast-info { border-left: 4px solid var(--color-info); }

@keyframes toast-in {
  from {
    opacity: 0;
    transform: translateY(16px) scale(0.95);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}


/* ----------------------------------------------------------
   21. Responsive Design
   ---------------------------------------------------------- */

/* Large screens: sidebar + 4-column grid */
@media (min-width: 1024px) {
  .tools-grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }
}

/* Tablet: 768px - 1023px */
@media (max-width: 1023px) {
  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .main-content {
    margin-left: 0;
  }

  .footer {
    margin-left: 0;
  }

  .tools-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Mobile: < 768px */
@media (max-width: 767px) {
  /* Navbar */
  .navbar-search {
    display: none;
  }

  .hamburger {
    display: flex;
  }

  .lang-label span {
    display: none;
  }

  /* Sidebar overlay */
  .sidebar-overlay {
    display: block;
    opacity: 0;
    pointer-events: none;
  }

  .sidebar-overlay.visible {
    opacity: 1;
    pointer-events: auto;
  }

  /* Main Content */
  .main-content {
    padding: var(--space-6) var(--space-4);
  }

  /* Tools Grid */
  .tools-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-3);
  }

  /* Tool Card */
  .tool-card {
    padding: var(--space-4);
  }

  /* Welcome Section */
  .welcome-section h1,
  .welcome-section .welcome-title {
    font-size: var(--font-size-2xl);
  }

  .welcome-section p,
  .welcome-section .welcome-desc {
    font-size: var(--font-size-sm);
  }

  /* Footer */
  .footer-features {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
  }

  .footer-bottom {
    flex-direction: column;
    gap: var(--space-6);
  }

  .footer-links-group {
    flex-wrap: wrap;
    gap: var(--space-6);
  }

  .footer-copyright {
    font-size: var(--font-size-xs);
  }

  /* Container */
  .container {
    padding: 0 var(--space-4);
  }

  /* Button Group */
  .btn-group {
    flex-direction: column;
  }

  .btn-group .btn {
    width: 100%;
  }
}

/* Small Mobile: < 480px */
@media (max-width: 479px) {
  .tools-grid {
    grid-template-columns: 1fr;
  }

  .navbar-logo {
    font-size: var(--font-size-base);
  }

  .navbar-actions {
    gap: 0;
  }

  .footer-features {
    grid-template-columns: 1fr;
  }
}

/* Large Desktop: > 1440px */
@media (min-width: 1440px) {
  .tools-grid {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--space-5);
  }
}

/* Print Styles */
@media print {
  .navbar,
  .sidebar,
  .sidebar-overlay,
  .footer,
  .ad-slot {
    display: none !important;
  }

  .main-content {
    margin-left: 0;
    padding: 0;
  }

  .main-layout {
    margin-top: 0;
  }

  body {
    color: #000;
    background: #fff;
  }
}


/* ----------------------------------------------------------
   22. Tool Page Specific Styles
   (For tools/*/*.html pages with header/layout structure)
   ---------------------------------------------------------- */

/* Header (Tool Page) */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background-color: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-sticky);
}

html.dark .header {
  background-color: rgba(11, 15, 26, 0.72);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
  gap: var(--space-4);
}

/* Logo (Tool Page) */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  text-decoration: none;
  flex-shrink: 0;
  letter-spacing: -0.02em;
}

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

.logo svg,
.logo img {
  width: 28px;
  height: 28px;
}

/* Header Search (Tool Page) */
.header-search {
  flex: 1;
  max-width: 420px;
  position: relative;
  display: flex;
  align-items: center;
}

.header-search svg {
  position: absolute;
  left: 12px;
  width: 16px;
  height: 16px;
  color: var(--color-text-tertiary);
  pointer-events: none;
}

.header-search input {
  width: 100%;
  height: 36px;
  padding: 0 var(--space-4) 0 36px;
  border: 1px solid transparent;
  border-radius: var(--radius-full);
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
  font-size: var(--font-size-sm);
  transition: all var(--transition-base);
  outline: none;
}

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

.header-search input:hover {
  background-color: var(--color-bg-secondary);
}

.header-search input:focus {
  border-color: var(--color-border-focus);
  background-color: var(--color-surface);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

html.dark .header-search input:focus {
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

/* Header Actions (Tool Page) */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-shrink: 0;
}

/* Language & Theme Buttons (Tool Page) */
.lang-btn,
.theme-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  background: transparent;
  border: none;
  cursor: pointer;
}

.lang-btn:hover,
.theme-btn:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
}

.lang-btn svg,
.theme-btn svg {
  width: 18px;
  height: 18px;
}

/* Breadcrumb (Tool Page) */
.breadcrumb {
  padding: var(--space-4) 0;
  margin-top: var(--nav-height);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.breadcrumb a {
  color: var(--color-text-link);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

/* Tool Page Layout */
.tool-page {
  min-height: calc(100vh - var(--nav-height));
  padding-bottom: var(--space-8);
}

.tool-layout {
  display: flex;
  gap: var(--space-6);
  padding-top: var(--space-6);
}

.tool-main {
  flex: 1;
  min-width: 0;
}

.tool-sidebar {
  width: 280px;
  flex-shrink: 0;
}

.tool-sidebar .ad-slot {
  position: sticky;
  top: calc(var(--nav-height) + var(--space-6));
}

/* Ad Placeholder */
.ad-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  min-height: 250px;
  color: var(--color-text-tertiary);
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* Tool Header (within tool page) */
.tool-header {
  margin-bottom: var(--space-6);
}

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

.tool-header .tool-icon svg {
  width: 24px;
  height: 24px;
}

.tool-header h1 {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: var(--space-2);
  letter-spacing: -0.02em;
}

.tool-header p {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

/* Tool Workspace (within tool page) */
.tool-workspace {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

/* Tool Page Responsive */
@media (max-width: 1023px) {
  .tool-sidebar {
    display: none;
  }

  .breadcrumb {
    padding: var(--space-3) var(--space-4);
  }

  .header-search {
    display: none;
  }
}

@media (max-width: 767px) {
  .header-inner {
    padding: 0 var(--space-4);
  }

  .tool-layout {
    padding-top: var(--space-4);
  }

  .tool-workspace {
    padding: var(--space-4);
  }

  .tool-header h1 {
    font-size: var(--font-size-xl);
  }
}