/* CSS Variables for theming */
:root {
  /* Colors - Dark theme by default */
  --color-bg-primary: #0a0a0b;
  --color-bg-secondary: #111113;
  --color-bg-tertiary: #1a1a1d;
  --color-bg-card: #18181b;

  --color-text-primary: #fafafa;
  --color-text-secondary: #a1a1aa;
  --color-text-muted: #71717a;

  --color-accent: #f97316;
  --color-accent-hover: #ea580c;
  --color-accent-muted: rgba(249, 115, 22, 0.15);

  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --color-info: #22d3ee;

  --color-border: #27272a;
  --color-border-hover: #3f3f46;

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Andale Mono', monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

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

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);

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

  /* Focus ring */
  --focus-ring: 0 0 0 2px var(--color-bg-primary), 0 0 0 4px var(--color-accent);
}

/* Light theme - System preference */
@media (prefers-color-scheme: light) {
  :root {
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #fafafa;
    --color-bg-tertiary: #f5f5f5;
    --color-bg-card: #ffffff;

    --color-text-primary: #171717;
    --color-text-secondary: #404040;
    --color-text-muted: #737373;

    --color-border: #e5e5e5;
    --color-border-hover: #d4d4d4;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  }
}

/* Manual theme override - Dark */
.theme-dark {
  --color-bg-primary: #0a0a0b;
  --color-bg-secondary: #111113;
  --color-bg-tertiary: #1a1a1d;
  --color-bg-card: #18181b;

  --color-text-primary: #fafafa;
  --color-text-secondary: #a1a1aa;
  --color-text-muted: #71717a;

  --color-border: #27272a;
  --color-border-hover: #3f3f46;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
}

/* Manual theme override - Light */
.theme-light {
  --color-bg-primary: #ffffff;
  --color-bg-secondary: #fafafa;
  --color-bg-tertiary: #f5f5f5;
  --color-bg-card: #ffffff;

  --color-text-primary: #171717;
  --color-text-secondary: #404040;
  --color-text-muted: #737373;

  --color-border: #e5e5e5;
  --color-border-hover: #d4d4d4;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

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

/* Base styles */
html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-accent);
  color: var(--color-bg-primary);
  font-weight: 600;
  border-radius: var(--radius-md);
  z-index: 1000;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-md);
  outline: none;
}

/* Visually hidden for screen readers */
.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;
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* Header */
.header {
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-secondary);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-primary);
}

.logo-icon {
  color: var(--color-accent);
}

.tagline {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  margin-top: var(--space-xs);
}

/* Main content */
.main {
  flex: 1;
  padding: var(--space-2xl) 0;
}

/* Hero section */
.hero {
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.hero-title {
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  font-weight: 700;
  margin-bottom: var(--space-md);
  color: var(--color-text-primary);
}

.hero-description {
  color: var(--color-text-secondary);
  font-size: 1.125rem;
  max-width: 600px;
  margin: 0 auto var(--space-xl);
}

/* Analyze form */
.analyze-form {
  max-width: 600px;
  margin: 0 auto;
}

.input-group {
  display: flex;
  gap: var(--space-sm);
}

.input-group input {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  font-size: 1rem;
  color: var(--color-text-primary);
  background: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input-group input:hover {
  border-color: var(--color-border-hover);
}

.input-group input:focus {
  border-color: var(--color-accent);
  box-shadow: var(--focus-ring);
}

.input-group input::placeholder {
  color: var(--color-text-muted);
}

.input-help {
  color: var(--color-text-muted);
  font-size: 0.875rem;
  margin-top: var(--space-sm);
  text-align: left;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
  min-width: 120px;
  min-height: 44px;
}

.btn:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}

.btn:active {
  transform: scale(0.98);
}

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

.btn-primary:hover {
  background: var(--color-accent-hover);
}

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-loading {
  display: none;
}

.btn.loading .btn-text {
  display: none;
}

.btn.loading .btn-loading {
  display: block;
}

.spinner {
  width: 20px;
  height: 20px;
  animation: spin 1s linear infinite;
}

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

/* Error message */
.error-message {
  margin-top: var(--space-md);
  padding: var(--space-md);
  background: rgba(239, 68, 68, 0.15);
  border: 1px solid var(--color-error);
  border-radius: var(--radius-md);
  color: var(--color-error);
  font-size: 0.875rem;
}

/* Results section */
.results {
  margin-top: var(--space-2xl);
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--space-xl);
  color: var(--color-text-primary);
}

/* Score card */
.score-card {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
  padding: var(--space-xl);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-xl);
}

.score-circle {
  position: relative;
  width: 120px;
  height: 120px;
  flex-shrink: 0;
}

.score-svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.score-bg {
  fill: none;
  stroke: var(--color-bg-tertiary);
  stroke-width: 8;
}

.score-progress {
  fill: none;
  stroke: var(--color-accent);
  stroke-width: 8;
  stroke-linecap: round;
  stroke-dasharray: 339.292;
  stroke-dashoffset: 339.292;
  transition: stroke-dashoffset 1s ease-out, stroke var(--transition-normal);
}

.score-progress.good {
  stroke: var(--color-success);
}

.score-progress.warning {
  stroke: var(--color-warning);
}

.score-progress.error {
  stroke: var(--color-error);
}

.score-value {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

#score-number {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1;
}

.score-label {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.score-info {
  flex: 1;
}

.analyzed-url {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-accent);
  word-break: break-all;
  margin-bottom: var(--space-sm);
}

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

/* Issues summary */
.issues-summary {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
}

.issue-count {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  flex: 1;
  min-width: 140px;
}

.issue-icon {
  width: 24px;
  height: 24px;
}

.issue-count.error .issue-icon {
  color: var(--color-error);
}

.issue-count.warning .issue-icon {
  color: var(--color-warning);
}

.issue-count.info .issue-icon {
  color: var(--color-info);
}

.issue-count .count {
  font-size: 1.5rem;
  font-weight: 700;
}

.issue-count .label {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

/* Tabs */
.tabs {
  display: flex;
  gap: var(--space-xs);
  margin-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
  overflow-x: auto;
}

.tab {
  padding: var(--space-md) var(--space-lg);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  min-height: 44px;
}

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

.tab:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}

.tab.active {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

/* Tab panels */
.tab-panel {
  animation: fadeIn var(--transition-normal);
}

.tab-panel[hidden] {
  display: none;
}

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

/* Overview grid */
.overview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-md);
}

.overview-card {
  padding: var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.overview-card h4 {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.overview-value {
  color: var(--color-text-primary);
  font-size: 0.9375rem;
  line-height: 1.5;
  word-break: break-word;
}

.overview-value.missing {
  color: var(--color-error);
  font-style: italic;
}

.overview-value.truncated::after {
  content: '...';
  color: var(--color-text-muted);
}

/* Issues list */
.issues-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.issue-item {
  padding: var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  border-left: 4px solid;
}

.issue-item.error {
  border-left-color: var(--color-error);
}

.issue-item.warning {
  border-left-color: var(--color-warning);
}

.issue-item.info {
  border-left-color: var(--color-info);
}

.issue-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.issue-badge {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
}

.issue-item.error .issue-badge {
  background: rgba(239, 68, 68, 0.15);
  color: var(--color-error);
}

.issue-item.warning .issue-badge {
  background: rgba(245, 158, 11, 0.15);
  color: var(--color-warning);
}

.issue-item.info .issue-badge {
  background: rgba(34, 211, 238, 0.15);
  color: var(--color-info);
}

.issue-category {
  font-weight: 600;
  color: var(--color-text-primary);
}

.issue-message {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.issue-impact {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  font-style: italic;
}

/* Recommendations */
.recommendations-content {
  padding: var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  line-height: 1.8;
}

.recommendations-content p {
  margin-bottom: var(--space-md);
}

.recommendations-content ol,
.recommendations-content ul {
  margin: var(--space-md) 0;
  padding-left: var(--space-xl);
}

.recommendations-content li {
  margin-bottom: var(--space-md);
  color: var(--color-text-secondary);
}

.recommendations-content strong {
  color: var(--color-text-primary);
}

/* Details grid */
.details-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.details-section {
  padding: var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.details-section h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}

.details-content {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.details-row {
  display: flex;
  justify-content: space-between;
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
}

.details-row:last-child {
  border-bottom: none;
}

.details-label {
  color: var(--color-text-muted);
}

.details-value {
  color: var(--color-text-primary);
  font-weight: 500;
  text-align: right;
  max-width: 60%;
  word-break: break-word;
}

.details-value.success {
  color: var(--color-success);
}

.details-value.error {
  color: var(--color-error);
}

.heading-item {
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
}

.heading-item:last-child {
  border-bottom: none;
}

.heading-tag {
  display: inline-block;
  min-width: 2.5rem;
  padding: var(--space-xs) var(--space-sm);
  background: var(--color-accent-muted);
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  margin-right: var(--space-sm);
}

.image-url {
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  word-break: break-all;
}

.image-url:last-child {
  border-bottom: none;
}

/* Features section */
.features {
  margin-top: var(--space-2xl);
  padding-top: var(--space-2xl);
  border-top: 1px solid var(--color-border);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-lg);
}

.feature-card {
  padding: var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-align: center;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

.feature-card:hover {
  border-color: var(--color-border-hover);
  transform: translateY(-2px);
}

.feature-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto var(--space-md);
  color: var(--color-accent);
}

.feature-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
}

.feature-card p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

/* Footer */
.footer {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border);
  background: var(--color-bg-secondary);
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

.footer-note {
  color: var(--color-text-muted);
  font-size: 0.75rem;
  margin-top: var(--space-sm);
}

/* Responsive */
@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-md);
  }

  .input-group {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .score-card {
    flex-direction: column;
    text-align: center;
  }

  .issues-summary {
    flex-direction: column;
  }

  .tabs {
    justify-content: flex-start;
    padding-bottom: var(--space-sm);
  }
}

/* Theme switcher */
.theme-switcher {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.theme-btn {
  background: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 500;
  transition: background var(--transition-fast), border-color var(--transition-fast);
  min-height: 44px;
}

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

.theme-btn[aria-pressed="true"] {
  background: var(--color-accent);
  color: #000;
  border-color: var(--color-accent);
  font-weight: 600;
}

/* Print styles */
@media print {
  .skip-link,
  .analyze-form,
  .tabs,
  .features,
  .footer,
  .theme-switcher {
    display: none;
  }

  body {
    background: white;
    color: black;
  }

  .score-card,
  .overview-card,
  .issue-item,
  .details-section {
    background: white;
    border: 1px solid #ccc;
  }
}