/* ===================================
   CSS Variables - Design Tokens
   =================================== */

:root {
  /* Colors - Light Mode */
  --color-primary: #4285f4;
  --color-primary-hover: #357ae8;
  --color-primary-light: rgba(66, 133, 244, 0.1);
  --color-secondary: #34a853;
  --color-background: #f8f9fa;
  --color-surface: #ffffff;
  --color-surface-hover: #f1f3f4;
  --color-text-primary: #202124;
  --color-text-secondary: #5f6368;
  --color-text-muted: #9aa0a6;
  --color-border: #dadce0;
  --color-shadow: rgba(0, 0, 0, 0.1);
  --color-shadow-strong: rgba(0, 0, 0, 0.2);
  
  /* Sizing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-md: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  
  /* Layout */
  --max-width: 600px;
  --header-height: 60px;
}

/* Dark Mode Colors */
@media (prefers-color-scheme: dark) {
  :root {
    --color-primary: #8ab4f8;
    --color-primary-hover: #aecbfa;
    --color-primary-light: rgba(138, 180, 248, 0.15);
    --color-secondary: #81c995;
    --color-background: #1a1a2e;
    --color-surface: #16213e;
    --color-surface-hover: #1f2b4a;
    --color-text-primary: #e8eaed;
    --color-text-secondary: #bdc1c6;
    --color-text-muted: #9aa0a6;
    --color-border: #3c4043;
    --color-shadow: rgba(0, 0, 0, 0.3);
    --color-shadow-strong: rgba(0, 0, 0, 0.5);
  }
}

/* ===================================
   Reset & Base Styles
   =================================== */

*, *::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-family);
  background-color: var(--color-background);
  color: var(--color-text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* ===================================
   Utility Classes
   =================================== */

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

.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-primary);
  color: white;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-sm);
  z-index: 1000;
  transition: top var(--transition-fast);
  text-decoration: none;
  font-weight: 500;
}

.skip-link:focus {
  top: var(--spacing-md);
}

/* ===================================
   Header
   =================================== */

.header {
  padding: var(--spacing-xl) var(--spacing-md);
  text-align: center;
}

.logo-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-md);
}

.logo {
  max-width: 180px;
  height: auto;
  animation: logoFloat 3s ease-in-out infinite;
  filter: drop-shadow(0 4px 12px var(--color-shadow));
  transition: transform var(--transition-normal);
}

.logo:hover {
  transform: scale(1.05);
}

@keyframes logoFloat {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-8px);
  }
}

/* ===================================
   Main Content
   =================================== */

.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0 var(--spacing-md);
  gap: var(--spacing-xl);
}

/* ===================================
   Search Section
   =================================== */

.search-section {
  width: 100%;
  max-width: var(--max-width);
}

.search-container {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.search-form {
  width: 100%;
}

.search-box {
  display: flex;
  align-items: stretch;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--spacing-sm);
  box-shadow: 0 2px 8px var(--color-shadow),
              0 4px 16px var(--color-shadow);
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition-normal), border-color var(--transition-normal);
  gap: var(--spacing-xs);
}

.search-box:focus-within {
  box-shadow: 0 4px 16px var(--color-shadow-strong);
  border-color: var(--color-primary);
}

/* Search Engine Select */
#engine-select {
  flex-shrink: 0;
  min-width: 140px;
  padding: var(--spacing-sm) var(--spacing-md);
  border: none;
  background: var(--color-surface-hover);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: background-color var(--transition-fast);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%235f6368' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10l-5 5z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  padding-right: 28px;
}

#engine-select:hover {
  background: var(--color-primary-light);
}

#engine-select:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Input Wrapper */
.input-wrapper {
  flex: 1;
  display: flex;
  align-items: center;
  position: relative;
  min-width: 0;
}

#search {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  padding-right: 36px;
  border: none;
  background: transparent;
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
  outline: none;
}

#search::placeholder {
  color: var(--color-text-muted);
}

#search::-webkit-search-cancel-button,
#search::-webkit-search-decoration {
  display: none;
}

/* Clear Button */
.clear-btn {
  position: absolute;
  right: var(--spacing-xs);
  background: none;
  border: none;
  padding: var(--spacing-xs);
  cursor: pointer;
  color: var(--color-text-muted);
  font-size: var(--font-size-md);
  border-radius: var(--radius-full);
  transition: color var(--transition-fast), background-color var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
}

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

/* Submit Button */
#go {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-size: var(--font-size-md);
  font-weight: 600;
  cursor: pointer;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

#go:hover {
  background: var(--color-primary-hover);
  transform: translateY(-1px);
}

#go:active {
  transform: translateY(0);
}

#go:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-icon {
  font-size: var(--font-size-lg);
  transition: transform var(--transition-fast);
}

#go:hover .btn-icon {
  transform: translateX(3px);
}

/* Keyboard Hints */
.keyboard-hints {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
}

.hint {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-family);
  font-size: var(--font-size-xs);
  box-shadow: 0 1px 2px var(--color-shadow);
  min-width: 24px;
}

/* ===================================
   Quick Links
   =================================== */

.quick-links {
  width: 100%;
  max-width: var(--max-width);
}

.quick-links-nav {
  display: flex;
  justify-content: center;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.quick-link {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-md);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
  transition: all var(--transition-fast);
  min-width: 80px;
}

.quick-link:hover {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px var(--color-shadow);
}

.quick-link:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.quick-link-icon {
  font-size: 1.5rem;
}

.quick-link-text {
  font-size: var(--font-size-sm);
  font-weight: 500;
}

/* ===================================
   Footer
   =================================== */

.footer {
  padding: var(--spacing-lg) var(--spacing-md);
  text-align: center;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

.footer-text {
  margin-bottom: var(--spacing-xs);
}

.footer-text a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.footer-text a:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}

.footer-meta {
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
}

.engine-indicator {
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--color-primary-light);
  border-radius: var(--radius-full);
}

/* ===================================
   Responsive Design
   =================================== */

/* Mobile - Small screens */
@media (max-width: 480px) {
  .header {
    padding: var(--spacing-lg) var(--spacing-md);
  }
  
  .logo {
    max-width: 140px;
  }
  
  .search-box {
    flex-direction: column;
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    gap: var(--spacing-sm);
  }
  
  #engine-select {
    width: 100%;
    text-align: center;
    padding-right: var(--spacing-md);
    background-position: right 12px center;
  }
  
  .input-wrapper {
    width: 100%;
  }
  
  #go {
    width: 100%;
    justify-content: center;
    padding: var(--spacing-md);
  }
  
  .keyboard-hints {
    display: none;
  }
  
  .quick-links-nav {
    gap: var(--spacing-sm);
  }
  
  .quick-link {
    min-width: 70px;
    padding: var(--spacing-sm);
  }
}

/* Tablet */
@media (min-width: 481px) and (max-width: 768px) {
  .search-box {
    padding: var(--spacing-sm);
  }
  
  #engine-select {
    min-width: 120px;
  }
  
  .btn-text {
    display: none;
  }
  
  .btn-icon {
    font-size: var(--font-size-xl);
  }
  
  #go {
    padding: var(--spacing-sm) var(--spacing-md);
  }
}

/* Desktop */
@media (min-width: 769px) {
  .header {
    padding: var(--spacing-2xl) var(--spacing-md);
  }
  
  .main {
    gap: var(--spacing-2xl);
  }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .logo {
    animation: none;
  }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
  :root {
    --color-border: var(--color-text-primary);
  }
  
  .search-box {
    border-width: 2px;
  }
  
  #go {
    font-weight: 700;
  }
}

/* Print Styles */
@media print {
  .keyboard-hints,
  .quick-links,
  .footer {
    display: none;
  }
  
  body {
    background: white;
    color: black;
  }
  
  .search-box {
    box-shadow: none;
    border: 1px solid black;
  }
}