/**
 * PowerReader - Base Styles
 *
 * CSS custom properties sourced from shared/enums.js THEME_COLORS.
 * Font stack and sizes per T04_FRONTEND/UI_LOCALIZATION.md.
 */

/* ==============================================
   CSS Custom Properties
   ============================================== */
:root {
  /* Bias colors (THEME_COLORS) */
  --color-bias-extreme-left: #0066CC;
  --color-bias-left: #3399FF;
  --color-bias-center-left: #6699CC;
  --color-bias-center: #999999;
  --color-bias-center-right: #CC6666;
  --color-bias-right: #FF6666;
  --color-bias-extreme-right: #CC0000;

  /* Controversy colors (THEME_COLORS) */
  --color-controversy-low: #28A745;
  --color-controversy-moderate: #FFC107;
  --color-controversy-high: #FD7E14;
  --color-controversy-very-high: #DC3545;

  /* Brand */
  --color-primary: #1A73E8;
  --color-primary-light: #4A90E2;
  --color-bg: #FFFFFF;
  --color-bg-secondary: #F5F5F5;
  --color-text: #212121;
  --color-text-secondary: #757575;
  --color-border: #E0E0E0;

  /* Font stack (UI_LOCALIZATION.md Section 9) */
  --font-sans: 'Noto Sans TC', 'Microsoft JhengHei', 'PingFang TC',
               'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'Source Code Pro', 'Noto Sans Mono CJK TC',
               'Microsoft JhengHei', Consolas, monospace;

  /* Font sizes */
  --text-h1: 24px;
  --text-h2: 20px;
  --text-h3: 18px;
  --text-body: 16px;
  --text-caption: 14px;
  --text-small: 12px;

  /* Layout */
  --max-width: 768px;
  --bottom-nav-height: 56px;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
}

/* ==============================================
   Base Reset & Box-Sizing
   ============================================== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: var(--text-body);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding-bottom: var(--bottom-nav-height);
}

/* ==============================================
   Typography
   ============================================== */
h1 { font-size: var(--text-h1); font-weight: 700; }
h2 { font-size: var(--text-h2); font-weight: 700; }
h3 { font-size: var(--text-h3); font-weight: 700; }

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

a:hover {
  text-decoration: underline;
}

/* ==============================================
   Layout Container (mobile-first, max-width)
   ============================================== */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing-md);
}

header {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing-md);
}

/* ==============================================
   Skip Link (WCAG 2.4.1)
   ============================================== */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--spacing-md);
  z-index: 9999;
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-primary);
  color: #FFFFFF;
  font-size: var(--text-body);
  border-radius: 4px;
  transition: top 0.2s;
}

.skip-link:focus {
  top: var(--spacing-sm);
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ==============================================
   Focus Indicators (WCAG 2.4.7)
   ============================================== */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ==============================================
   Offline Banner
   ============================================== */
.offline-banner {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: #FFC107;
  color: #212121;
  text-align: center;
  font-size: var(--text-caption);
  font-weight: 700;
}

.offline-banner[hidden] {
  display: none;
}

/* ==============================================
   Bottom Navigation
   ============================================== */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 900;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  height: var(--bottom-nav-height);
  background-color: var(--color-bg);
  border-top: 1px solid var(--color-border);
}

.bottom-nav__item {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  font-size: var(--text-small);
  text-decoration: none;
  transition: color 0.2s;
}

.bottom-nav__item:hover,
.bottom-nav__item[aria-current="page"] {
  color: var(--color-primary);
  text-decoration: none;
}

/* ==============================================
   Bias Bar
   ============================================== */
.bias-bar {
  position: relative;
  width: 100%;
  height: 12px;
  border-radius: 6px;
  background: linear-gradient(
    to right,
    var(--color-bias-extreme-left) 0%,
    var(--color-bias-left) 20%,
    var(--color-bias-center) 50%,
    var(--color-bias-right) 80%,
    var(--color-bias-extreme-right) 100%
  );
}

.bias-bar__indicator {
  position: absolute;
  top: 50%;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background-color: var(--color-text);
  border: 2px solid var(--color-bg);
  transform: translate(-50%, -50%);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

/* ==============================================
   Controversy Meter
   ============================================== */
.controversy-meter {
  position: relative;
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background-color: var(--color-bg-secondary);
  overflow: hidden;
}

.controversy-meter__fill {
  height: 100%;
  border-radius: 4px;
  transition: width 0.3s ease;
}

.controversy-meter__fill--low {
  background-color: var(--color-controversy-low);
}

.controversy-meter__fill--moderate {
  background-color: var(--color-controversy-moderate);
}

.controversy-meter__fill--high {
  background-color: var(--color-controversy-high);
}

.controversy-meter__fill--very-high {
  background-color: var(--color-controversy-very-high);
}

/* ==============================================
   Color-blind safe patterns
   ============================================== */
@media (prefers-contrast: more) {
  .bias-bar {
    background: linear-gradient(
      to right,
      #000080 0%,
      #4169E1 20%,
      #808080 50%,
      #B22222 80%,
      #8B0000 100%
    );
    height: 16px;
  }

  .bias-bar__indicator {
    width: 20px;
    height: 20px;
    border: 3px solid #FFFFFF;
  }

  .controversy-meter {
    height: 12px;
  }

  :focus-visible {
    outline-width: 3px;
  }
}

/* ==============================================
   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;
}

/* ==============================================
   Responsive: mobile-first container
   ============================================== */
@media (min-width: 769px) {
  main,
  header {
    padding: var(--spacing-lg);
  }
}

/* ==============================================
   Buttons
   ============================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-sm) var(--spacing-md);
  border: none;
  border-radius: 8px;
  font-family: var(--font-sans);
  font-size: var(--text-body);
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.2s, opacity 0.2s;
  text-decoration: none;
}

.btn--primary {
  background-color: var(--color-primary);
  color: #FFFFFF;
}

.btn--primary:hover { opacity: 0.9; }

.btn--secondary {
  background-color: var(--color-bg-secondary);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

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

.btn--text {
  background: none;
  color: var(--color-primary);
  padding: var(--spacing-xs) var(--spacing-sm);
}

/* ==============================================
   Page Title
   ============================================== */
.page-title {
  margin-bottom: var(--spacing-md);
}

.section-heading {
  font-size: var(--text-h3);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

/* ==============================================
   Home Filters
   ============================================== */
.home-filters {
  margin-bottom: var(--spacing-md);
}

.home-filters__select {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-sans);
  font-size: var(--text-caption);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background-color: var(--color-bg);
  color: var(--color-text);
  appearance: auto;
}

/* ==============================================
   Article List
   ============================================== */
.article-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

/* ==============================================
   Article Card
   ============================================== */
.article-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--spacing-md);
  transition: box-shadow 0.2s, transform 0.1s;
}

.article-card:hover {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  transform: translateY(-1px);
}

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

.article-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-sm);
}

.article-card__source {
  display: inline-block;
  padding: 2px 8px;
  font-size: var(--text-small);
  font-weight: 700;
  color: var(--color-primary);
  background-color: #E8F0FE;
  border-radius: 4px;
}

.article-card__date {
  font-size: var(--text-small);
  color: var(--color-text-secondary);
}

.article-card__title {
  font-size: var(--text-h3);
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.article-card__summary {
  font-size: var(--text-caption);
  color: var(--color-text-secondary);
  line-height: 1.5;
  margin-bottom: var(--spacing-sm);
}

.article-card__footer {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

/* ==============================================
   Bias Indicator (compact, for cards)
   ============================================== */
.bias-indicator {
  display: inline-block;
  padding: 2px 8px;
  font-size: var(--text-small);
  font-weight: 700;
  border-radius: 4px;
  color: #FFFFFF;
}

.bias-indicator--extreme_left { background-color: var(--color-bias-extreme-left); }
.bias-indicator--left { background-color: var(--color-bias-left); }
.bias-indicator--center_left { background-color: var(--color-bias-center-left); }
.bias-indicator--center { background-color: var(--color-bias-center); }
.bias-indicator--center_right { background-color: var(--color-bias-center-right); }
.bias-indicator--right { background-color: var(--color-bias-right); }
.bias-indicator--extreme_right { background-color: var(--color-bias-extreme-right); }

/* ==============================================
   Bias Bar Labels
   ============================================== */
.bias-bar-wrapper {
  margin: var(--spacing-sm) 0;
}

.bias-bar__label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-xs);
  font-size: var(--text-caption);
}

.bias-bar__category {
  font-weight: 700;
}

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

/* ==============================================
   Controversy Badge
   ============================================== */
.controversy-badge {
  display: inline-block;
  padding: 2px 8px;
  font-size: var(--text-small);
  font-weight: 700;
  border-radius: 4px;
  color: #FFFFFF;
}

.controversy-badge--low { background-color: var(--color-controversy-low); }
.controversy-badge--moderate { background-color: var(--color-controversy-moderate); color: #212121; }
.controversy-badge--high { background-color: var(--color-controversy-high); }
.controversy-badge--very_high { background-color: var(--color-controversy-very-high); }

/* ==============================================
   Controversy Meter Labels
   ============================================== */
.controversy-meter-wrapper {
  margin: var(--spacing-sm) 0;
}

.controversy-meter__label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-xs);
  font-size: var(--text-caption);
}

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

/* ==============================================
   Article Detail
   ============================================== */
.article-detail__back {
  margin-bottom: var(--spacing-md);
}

.article-detail__meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.article-detail__date {
  font-size: var(--text-caption);
  color: var(--color-text-secondary);
}

.article-detail__title {
  font-size: var(--text-h1);
  line-height: 1.3;
  margin-bottom: var(--spacing-lg);
}

.article-detail__bias,
.article-detail__controversy {
  margin-bottom: var(--spacing-lg);
  padding: var(--spacing-md);
  background-color: var(--color-bg-secondary);
  border-radius: 12px;
}

.article-detail__summary {
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
}

.article-detail__actions {
  margin-bottom: var(--spacing-md);
}

/* ==============================================
   Knowledge Panel
   ============================================== */
.knowledge-panel {
  margin-top: var(--spacing-lg);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  overflow: hidden;
}

.knowledge-panel__summary {
  padding: var(--spacing-md);
  font-weight: 700;
  cursor: pointer;
  background-color: var(--color-bg-secondary);
}

.knowledge-panel__list {
  list-style: none;
  padding: 0;
}

.knowledge-panel__item {
  padding: var(--spacing-md);
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  align-items: baseline;
}

.knowledge-panel__snippet {
  width: 100%;
  font-size: var(--text-caption);
  color: var(--color-text-secondary);
  margin-top: var(--spacing-xs);
}

.knowledge-panel__score {
  font-size: var(--text-small);
  color: var(--color-text-secondary);
  margin-left: auto;
}

.knowledge-badge {
  display: inline-block;
  padding: 2px 6px;
  font-size: var(--text-small);
  font-weight: 700;
  border-radius: 4px;
  color: #FFFFFF;
}

.knowledge-badge--politician { background-color: #6366F1; }
.knowledge-badge--media { background-color: #EC4899; }
.knowledge-badge--topic { background-color: #F59E0B; color: #212121; }
.knowledge-badge--term { background-color: #10B981; }
.knowledge-badge--event { background-color: #EF4444; }

/* ==============================================
   Cluster Panel (Cross-Media Comparison)
   ============================================== */
.article-detail__cluster {
  margin-top: var(--spacing-lg);
}

.cluster-panel__desc {
  font-size: var(--text-caption);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.cluster-panel__list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.cluster-panel__item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  transition: background-color 0.2s;
}

.cluster-panel__item:hover {
  background-color: var(--color-bg-secondary);
}

.cluster-panel__title {
  flex: 1;
  font-size: var(--text-caption);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ==============================================
   Loading / Error / Empty States
   ============================================== */
.loading-state,
.loading-indicator {
  text-align: center;
  padding: var(--spacing-xl);
  color: var(--color-text-secondary);
  font-size: var(--text-body);
}

.error-state {
  text-align: center;
  padding: var(--spacing-xl);
}

.error-state p {
  color: var(--color-controversy-very-high);
  margin-bottom: var(--spacing-md);
}

.empty-state {
  text-align: center;
  padding: var(--spacing-xl) * 2;
  color: var(--color-text-secondary);
}

.empty-state__icon {
  font-size: 48px;
  margin-bottom: var(--spacing-md);
  opacity: 0.3;
}

/* ==============================================
   Scroll Sentinel (infinite scroll trigger)
   ============================================== */
.scroll-sentinel {
  height: 1px;
  width: 100%;
}

/* ==============================================
   Sync Failure Banner
   ============================================== */
.sync-failure-banner {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1001;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: #F8D7DA;
  color: #721C24;
  font-size: var(--text-caption);
  flex-wrap: wrap;
}

.sync-failure-banner .btn--text {
  color: #721C24;
  font-weight: 700;
  font-size: var(--text-caption);
}

/* ==============================================
   Privacy Consent Dialog
   ============================================== */
.consent-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md);
}

.consent-dialog {
  background: var(--color-bg);
  border-radius: 12px;
  padding: var(--spacing-lg);
  max-width: 400px;
  width: 100%;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.15);
}

.consent-dialog h3 {
  margin-bottom: var(--spacing-md);
}

.consent-dialog__link {
  display: block;
  margin-bottom: var(--spacing-md);
  color: var(--color-primary);
  text-decoration: underline;
}

.consent-dialog__checkbox {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
  cursor: pointer;
}

.consent-dialog__hint {
  color: var(--color-controversy-high);
  font-size: var(--text-caption);
  margin-bottom: var(--spacing-sm);
}

.consent-dialog__actions {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-md);
}

/* Additional page styles split into separate CSS files:
 * - css/analyze.css    (Phase 3)
 * - css/profile.css    (Phase 4)
 * - css/settings.css   (Phase 5)
 * - css/onboarding.css (Phase 6)
 */