/* CSS Variables for consistent theming */
:root {
  /* Colors */
  --primary-color: #1DA1F2;
  --primary-hover: #1991DA;
  --primary-dark: #0d8bd9;
  --secondary-color: #FF6B6B;
  --secondary-hover: #FF5252;
  --accent-color: #4ECDC4;
  --accent-hover: #26C6DA;
  
  --bg-primary: #FFFFFF;
  --bg-secondary: #F8FAFC;
  --bg-tertiary: #F1F5F9;
  --bg-modal: rgba(0, 0, 0, 0.8);
  
  --text-primary: #1E293B;
  --text-secondary: #64748B;
  --text-muted: #94A3B8;
  --text-white: #FFFFFF;
  
  --border-color: #E2E8F0;
  --border-focus: #3B82F6;
  --error-color: #EF4444;
  --success-color: #10B981;
  --warning-color: #F59E0B;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
  
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Shadows */
  --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 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Transitions */
  --transition-fast: 0.15s ease-out;
  --transition-normal: 0.25s ease-out;
  --transition-slow: 0.4s ease-out;
  
  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* Layout */
  --container-max-width: 600px;
  --header-height: 80px;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #0F172A;
    --bg-secondary: #1E293B;
    --bg-tertiary: #334155;
    
    --text-primary: #F1F5F9;
    --text-secondary: #CBD5E1;
    --text-muted: #94A3B8;
    
    --border-color: #475569;
  }
}

/* Reset and base styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Container and layout */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: var(--spacing-md);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-2xl);
}

/* Header */
header {
  text-align: center;
  animation: fadeInUp 0.8s ease-out;
}

.main-title {
  font-size: var(--font-size-4xl);
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  line-height: var(--line-height-tight);
}

.title-icon {
  font-size: 1.2em;
  animation: bounce 2s infinite;
}

.subtitle {
  font-size: var(--font-size-xl);
  color: var(--text-secondary);
  font-weight: 400;
  margin-bottom: var(--spacing-lg);
}

/* Input section */
.input-section {
  width: 100%;
  text-align: center;
  animation: fadeInUp 0.8s ease-out 0.2s both;
}

.checker-form {
  width: 100%;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
  align-items: center;
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  flex-direction: row;
  width: 100%;
  max-width: 400px;
  background: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--spacing-sm);
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
  min-height: 3rem;
}

.input-wrapper:focus-within {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(29, 161, 242, 0.1);
  transform: translateY(-2px);
}

.input-prefix {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--primary-color);
  padding: 0 var(--spacing-sm);
  user-select: none;
  line-height: 1;
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

#username-input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: var(--font-size-lg);
  font-weight: 500;
  color: var(--text-primary);
  padding: var(--spacing-md);
  outline: none;
  font-family: var(--font-mono);
  line-height: 1;
  height: auto;
  min-height: 1.5rem;
}

#username-input::placeholder {
  color: var(--text-muted);
  font-style: italic;
}

.check-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
  color: var(--text-white);
  border: none;
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-size: var(--font-size-lg);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-md);
  min-width: 160px;
  position: relative;
  overflow: hidden;
}

.check-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  background: linear-gradient(135deg, var(--primary-hover), var(--primary-color));
}

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

.check-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-icon {
  font-size: 1.2em;
  transition: transform var(--transition-normal);
}

.check-btn:hover .btn-icon {
  transform: scale(1.1);
}

.input-hint {
  font-size: var(--font-size-sm);
  color: var(--text-muted);
  text-align: center;
  margin-top: var(--spacing-sm);
}

/* Loading section */
.loading-section {
  text-align: center;
  animation: fadeIn 0.5s ease-out;
}

.loading-animation {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xl);
}

.spinner {
  width: 60px;
  height: 60px;
  border: 4px solid var(--border-color);
  border-top: 4px solid var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

.loading-text {
  color: var(--text-secondary);
}

#loading-message {
  font-size: var(--font-size-lg);
  font-weight: 500;
  margin-bottom: var(--spacing-sm);
}

.loading-dots {
  display: flex;
  gap: var(--spacing-xs);
  justify-content: center;
}

.loading-dots span {
  width: 8px;
  height: 8px;
  background: var(--primary-color);
  border-radius: 50%;
  animation: dot-bounce 1.5s infinite ease-in-out;
}

.loading-dots span:nth-child(2) {
  animation-delay: 0.1s;
}

.loading-dots span:nth-child(3) {
  animation-delay: 0.2s;
}

/* Results section */
.results-section {
  width: 100%;
  animation: fadeInUp 0.6s ease-out;
}

.result-card {
  background: var(--bg-secondary);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--border-color);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.result-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-color), var(--accent-color), var(--secondary-color));
}

.result-header {
  margin-bottom: var(--spacing-xl);
}

#result-username {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-lg);
}

.measurement-display {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.size-number {
  font-size: 4rem;
  font-weight: 800;
  color: var(--primary-color);
  line-height: 1;
  font-family: var(--font-mono);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.size-unit {
  font-size: var(--font-size-xl);
  color: var(--text-secondary);
  font-weight: 600;
}

.result-body {
  margin-bottom: var(--spacing-2xl);
}

.result-description {
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
  font-style: italic;
}

.confidence-bar {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  align-items: center;
}

.confidence-label {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.confidence-meter {
  width: 100%;
  max-width: 200px;
  height: 8px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-full);
  overflow: hidden;
  position: relative;
}

.confidence-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--warning-color), var(--success-color));
  border-radius: var(--radius-full);
  transition: width 1s ease-out 0.5s;
  width: 0;
}

.confidence-percentage {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--success-color);
  font-family: var(--font-mono);
}

.percentile-display {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  align-items: center;
  margin-top: var(--spacing-lg);
  padding: var(--spacing-md);
  background: linear-gradient(135deg, rgba(29, 161, 242, 0.1), rgba(76, 60, 196, 0.1));
  border-radius: var(--radius-lg);
  border: 1px solid rgba(29, 161, 242, 0.2);
}

.percentile-label {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.percentile-value {
  display: flex;
  align-items: baseline;
  gap: var(--spacing-xs);
}

#percentile-number {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  color: var(--primary-color);
  font-family: var(--font-mono);
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.percentile-suffix {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--text-secondary);
}

.result-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

.share-btn,
.try-again-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-lg);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-normal);
  text-decoration: none;
  border: none;
  font-size: var(--font-size-base);
}

.share-btn {
  background: var(--primary-color);
  color: var(--text-white);
}

.share-btn:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.try-again-btn {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.try-again-btn:hover {
  background: var(--bg-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* Footer */
footer {
  margin-top: auto;
  text-align: center;
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--border-color);
  width: 100%;
}

.disclaimer {
  margin-bottom: var(--spacing-lg);
}

.disclaimer p {
  font-size: var(--font-size-sm);
  color: var(--text-muted);
  margin-bottom: var(--spacing-xs);
}

.footer-links {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-sm);
}

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

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

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

/* Modals */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--bg-modal);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: var(--spacing-md);
  animation: fadeIn 0.3s ease-out;
}

.modal-content {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  max-width: 500px;
  width: 100%;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: var(--shadow-xl);
  animation: scaleIn 0.3s ease-out;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--text-primary);
}

.modal-close {
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  color: var(--text-muted);
  cursor: pointer;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.modal-body {
  padding: var(--spacing-xl);
}

.modal-body p {
  margin-bottom: var(--spacing-md);
  line-height: var(--line-height-relaxed);
  color: var(--text-secondary);
}

.modal-body ul {
  margin: var(--spacing-md) 0;
  padding-left: var(--spacing-xl);
}

.modal-body li {
  margin-bottom: var(--spacing-sm);
  color: var(--text-secondary);
}

/* Utility classes */
.hidden {
  display: none !important;
}

.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;
}

/* Animations */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

@keyframes bounce {
  0%, 20%, 53%, 100% {
    transform: translateY(0);
  }
  40%, 43% {
    transform: translateY(-8px);
  }
  70% {
    transform: translateY(-4px);
  }
  90% {
    transform: translateY(-2px);
  }
}

@keyframes dot-bounce {
  0%, 80%, 100% {
    transform: scale(0.8);
    opacity: 0.5;
  }
  40% {
    transform: scale(1);
    opacity: 1;
  }
}

/* Responsive design */
@media (max-width: 640px) {
  :root {
    --font-size-4xl: 2rem;
    --font-size-3xl: 1.75rem;
    --font-size-2xl: 1.375rem;
    --spacing-2xl: 2rem;
    --spacing-3xl: 2.5rem;
  }
  
  .container {
    padding: var(--spacing-sm);
    gap: var(--spacing-xl);
  }
  
  .main-title {
    flex-direction: column;
    gap: var(--spacing-xs);
  }
  
  .result-card {
    padding: var(--spacing-xl);
  }
  
  .size-number {
    font-size: 3rem;
  }
  
  .result-actions {
    flex-direction: column;
  }
  
  .share-btn,
  .try-again-btn {
    width: 100%;
    justify-content: center;
  }
  
  .modal-content {
    margin: var(--spacing-md);
    max-height: calc(100vh - 2rem);
  }
  
  .input-group {
    gap: var(--spacing-md);
  }
  
  .check-btn {
    width: 100%;
    max-width: 400px;
  }
}

@media (max-width: 480px) {
  .container {
    min-height: 100vh;
    justify-content: flex-start;
    padding-top: var(--spacing-xl);
  }
  
  .measurement-display {
    flex-direction: column;
    gap: 0;
  }
  
  .size-number {
    font-size: 2.5rem;
  }
  
  .input-wrapper {
    padding: var(--spacing-md);
  }
}

/* Print styles */
@media print {
  .check-btn,
  .share-btn,
  .try-again-btn,
  footer {
    display: none;
  }
  
  .container {
    min-height: auto;
  }
  
  .result-card {
    box-shadow: none;
    border: 1px solid #000;
  }
}

/* High contrast mode */
@media (prefers-contrast: high) {
  :root {
    --primary-color: #0066CC;
    --text-primary: #000000;
    --text-secondary: #333333;
    --bg-primary: #FFFFFF;
    --border-color: #000000;
  }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .spinner {
    animation: none;
    border: 4px solid var(--primary-color);
  }
}