/* ============================================================
   CSS Variables — Design System (design-rules.md §13)
   ============================================================ */

:root {
  /* Colors */
  --color-bg: #FFFFFF;
  --color-bg-paper: #FCFCFA;
  --color-surface: #F9F9F9;
  --color-border: #E6E6E6;
  --color-text-primary: #242424;
  --color-text-secondary: #6B6B6B;
  --color-text-muted: #B3B3B3;
  --color-accent: #1A8917;
  --color-link: #1565C0;
  --color-highlight: #FFF176;
  --color-tag-bg: #F2F2F2;

  /* Typography */
  --font-serif: charter, Georgia, "Times New Roman", serif;
  --font-display: gt-super, Georgia, "Times New Roman", serif;
  --font-sans: sohne, "Helvetica Neue", Arial, sans-serif;
  --font-mono: source-code-pro, "Courier New", monospace;

  --text-hero: 46px;
  --text-hero-sub: 28px;
  --text-article-title: 32px;
  --text-article-h2: 24px;
  --text-article: 20px;
  --text-feed-title: 18px;
  --text-feed-preview: 14px;
  --text-ui: 14px;
  --text-small: 12px;
  --text-caption: 14px;

  --leading-body: 1.8;
  --leading-heading: 1.2;
  --leading-ui: 1.4;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;
  --space-4xl: 80px;

  /* Layout */
  --max-article: 680px;
  --max-feed: 1192px;
  --navbar-height: 65px;

  /* Radius */
  --radius-sm: 4px;
  --radius-pill: 99px;

  /* CTA sizing */
  --cta-height: 36px;
  --cta-height-lg: 48px;

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

/* Dark mode */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #191919;
    --color-bg-paper: #1D1D1B;
    --color-surface: #242424;
    --color-border: #2E2E2E;
    --color-text-primary: #E6E6E6;
    --color-text-secondary: #999999;
    --color-text-muted: #666666;
    --color-tag-bg: #2E2E2E;
  }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {

  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
  }
}

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

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  background: var(--color-bg);
  color: var(--color-text-primary);
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  line-height: var(--leading-ui);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-variant-ligatures: common-ligatures;
}

a {
  color: inherit;
  text-decoration: none;
}

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

/* ============================================================
   Divider (§5.9)
   ============================================================ */

.divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-xl) 0;
}

/* ============================================================
   Navbar (§5.1)
   ============================================================ */

.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  height: var(--navbar-height);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base);
}

.navbar.scrolled {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

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

.navbar-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  color: var(--color-text-primary);
}

.navbar-logo {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.5px;
}

.navbar-site-name {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  color: var(--color-text-secondary);
  font-weight: 400;
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.navbar-link {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  line-height: 1;
  color: var(--color-text-primary);
  text-decoration: none;
  transition: opacity var(--transition-fast);
}

.navbar-link:hover {
  text-decoration: underline;
}

.navbar-write {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  color: var(--color-text-primary);
  text-decoration: none;
}

.navbar-write:hover {
  text-decoration: underline;
}

/* ============================================================
   Buttons (§5.4, §5.5)
   ============================================================ */

.btn-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--color-text-primary);
  color: var(--color-bg);
  border-radius: var(--radius-pill);
  height: var(--cta-height);
  padding: 8px 20px;
  font-size: var(--text-ui);
  font-family: var(--font-sans);
  font-weight: 500;
  line-height: 1;
  letter-spacing: 0.01em;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: opacity var(--transition-fast);
  white-space: nowrap;
}

.btn-cta:hover {
  opacity: 0.85;
}

.btn-cta-lg {
  height: var(--cta-height-lg);
  padding: 12px 28px;
  font-size: 15px;
}

.btn-follow {
  background: var(--color-accent);
  color: #FFFFFF;
  border: none;
  border-radius: var(--radius-pill);
  font-size: var(--text-ui);
  font-family: var(--font-sans);
  padding: 7px 16px;
  cursor: pointer;
  transition: opacity var(--transition-fast);
  white-space: nowrap;
}

.btn-follow:hover {
  opacity: 0.85;
}

.btn-following {
  background: transparent;
  color: var(--color-text-primary);
  border: 1px solid var(--color-text-primary);
  border-radius: var(--radius-pill);
  font-size: var(--text-ui);
  font-family: var(--font-sans);
  padding: 7px 16px;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.btn-following:hover {
  background: var(--color-surface);
}

/* ============================================================
   Tag / Topic Pills (§5.3)
   ============================================================ */

.tag {
  display: inline-block;
  background: var(--color-tag-bg);
  color: var(--color-text-primary);
  font-size: 13px;
  font-family: var(--font-sans);
  padding: 6px 12px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition-fast);
  white-space: nowrap;
}

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

.topic-tab-active {
  background: var(--color-text-primary);
  color: var(--color-bg);
}

.article-card-hidden {
  display: none;
}

.feed-empty-state {
  padding: var(--space-xl) 0;
  color: var(--color-text-secondary);
  font-family: var(--font-sans);
  font-size: var(--text-ui);
}

/* ============================================================
   Hero Section (§12 – Homepage Logged Out)
   ============================================================ */

.hero {
  text-align: center;
  padding: var(--space-3xl) var(--space-lg) var(--space-2xl);
  max-width: var(--max-feed);
  margin: 0 auto;
}

.hero-title {
  font-family: var(--font-display);
  font-size: var(--text-hero);
  font-weight: 700;
  line-height: 1.18;
  color: var(--color-text-primary);
  text-wrap: balance;
  margin-bottom: var(--space-md);
}

.hero-subtitle {
  font-family: var(--font-sans);
  font-size: var(--text-hero-sub);
  font-weight: 400;
  line-height: 1.4;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
}

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

/* ============================================================
   Featured Topics Bar
   ============================================================ */

.topics-bar {
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-md) var(--space-lg);
}

.topics-bar-inner {
  max-width: var(--max-feed);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  overflow-x: auto;
  scrollbar-width: none;
}

.topics-label {
  font-family: var(--font-sans);
  font-size: var(--text-small);
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.topics-bar-inner::-webkit-scrollbar {
  display: none;
}

/* ============================================================
   Feed Layout
   ============================================================ */

.feed-layout {
  max-width: var(--max-feed);
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-lg);
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: var(--space-4xl);
  align-items: start;
}

.feed-list {
  min-width: 0;
}

/* ============================================================
   Article Card (§5.2)
   ============================================================ */

.article-card {
  padding: var(--space-xl) var(--space-sm);
  margin: 0 calc(-1 * var(--space-sm));
  border-bottom: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  transition: background var(--transition-base);
  cursor: pointer;
  text-decoration: none;
  color: inherit;
}

.article-card:hover {
  background: var(--color-surface);
}

.article-card:last-child {
  border-bottom: none;
}

.card-meta {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: var(--space-sm);
  font-size: var(--text-small);
  color: var(--color-text-secondary);
  font-family: var(--font-sans);
  width: 100%;
  text-align: left;
}

.card-avatar {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.card-author {
  font-weight: 700;
  color: var(--color-text-primary);
}

.card-meta-sep {
  color: var(--color-text-muted);
}

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

.card-body {
  display: flex;
  gap: var(--space-md);
  align-items: flex-start;
}

.card-text {
  flex: 1;
  min-width: 0;
}

.card-title {
  font-family: var(--font-serif);
  font-size: var(--text-feed-title);
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-text-primary);
  text-wrap: balance;
  margin-bottom: var(--space-xs);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-preview {
  font-family: var(--font-sans);
  font-size: var(--text-feed-preview);
  color: var(--color-text-secondary);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-thumbnail {
  width: 112px;
  height: 112px;
  border-radius: var(--radius-sm);
  object-fit: cover;
  flex-shrink: 0;
  background: var(--color-surface);
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: var(--space-sm);
  flex-wrap: wrap;
  width: 100%;
  text-align: left;
}

.card-read-time {
  font-size: var(--text-small);
  color: var(--color-text-secondary);
}

.card-actions {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  margin-left: auto;
}

.btn-icon {
  background: none;
  border: none;
  color: var(--color-text-secondary);
  cursor: pointer;
  padding: var(--space-xs);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: color var(--transition-fast);
  border-radius: var(--radius-sm);
}

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

/* ============================================================
   Sidebar
   ============================================================ */

.sidebar {
  position: sticky;
  top: calc(var(--navbar-height) + var(--space-xl));
}

.sidebar-section {
  margin-bottom: var(--space-2xl);
}

.sidebar-heading {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
}

.sidebar-pick {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
}

.sidebar-pick:last-child {
  border-bottom: none;
}

.sidebar-pick-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--text-small);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xs);
}

.sidebar-pick-avatar {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  flex-shrink: 0;
}

.sidebar-pick-title {
  font-family: var(--font-serif);
  font-size: var(--text-ui);
  font-weight: 700;
  color: var(--color-text-primary);
  text-wrap: pretty;
  line-height: 1.3;
}

.sidebar-topics {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

/* ============================================================
   Article Page (§5.6, §5.8, §12)
   ============================================================ */

.article-container {
  max-width: var(--max-article);
  margin: 0 auto;
  padding: var(--space-4xl) var(--space-lg) var(--space-2xl);
}

.article-header {
  margin-bottom: var(--space-xl);
}

.article-title {
  font-family: var(--font-serif);
  font-size: var(--text-article-title);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-primary);
  text-wrap: balance;
  margin-bottom: var(--space-md);
}

.article-subtitle {
  font-family: var(--font-serif);
  font-size: 22px;
  font-weight: 400;
  line-height: 1.5;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
}

.article-byline {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-2xl);
}

.byline-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.byline-info {
  flex: 1;
}

.byline-name {
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 700;
  color: var(--color-text-primary);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.byline-meta {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.4;
  margin-top: 2px;
}

.article-hero-image {
  width: 100%;
  max-height: 525px;
  object-fit: cover;
  margin-bottom: var(--space-xl);
  background: var(--color-surface);
}

.article-hero-image-full {
  height: 420px;
  border-radius: 0;
}

.article-hero-caption {
  text-align: center;
  font-size: var(--text-caption);
  color: var(--color-text-secondary);
  font-style: italic;
  font-family: var(--font-sans);
  margin-top: calc(-1 * var(--space-sm));
  margin-bottom: var(--space-xl);
}

/* Article body (§5.6) */
.article-body {
  font-family: var(--font-serif);
  font-size: var(--text-article);
  line-height: var(--leading-body);
  color: var(--color-text-primary);
  max-width: var(--max-article);
  margin: 0 auto;
}

.article-body p {
  margin-bottom: 2em;
}

/* Give article openings a classic editorial cue without overpowering the page. */
.article-body>p:first-of-type::first-letter {
  float: left;
  font-family: var(--font-display);
  font-size: 3.1em;
  line-height: 0.9;
  margin-right: 0.08em;
  margin-top: 0.03em;
}

.article-body h2 {
  font-family: var(--font-serif);
  font-size: var(--text-article-h2);
  font-weight: 700;
  line-height: 1.3;
  margin: 2.5em 0 0.5em;
}

.article-body h3 {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.3;
  margin: 2em 0 0.5em;
}

.article-body blockquote {
  border-left: 3px solid var(--color-text-primary);
  padding-left: var(--space-lg);
  font-style: italic;
  color: var(--color-text-secondary);
  margin: 2em 0;
}

.article-body img {
  width: 100%;
  margin: 2em 0;
}

.article-body figcaption {
  text-align: center;
  font-size: var(--text-caption);
  color: var(--color-text-secondary);
  font-style: italic;
  margin-top: -1.5em;
  font-family: var(--font-sans);
}

.article-body code {
  font-family: var(--font-mono);
  background: var(--color-tag-bg);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.85em;
}

.article-body pre {
  background: var(--color-tag-bg);
  padding: var(--space-lg);
  overflow-x: auto;
  border-radius: var(--radius-sm);
  margin: 2em 0;
}

.article-body pre code {
  background: none;
  padding: 0;
}

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

.article-body a:hover {
  opacity: 0.75;
}

.article-body ul,
.article-body ol {
  padding-left: 1.5em;
  margin-bottom: 2em;
}

.article-body li {
  margin-bottom: 0.5em;
}

/* ============================================================
   Article Engagement Bar (§5.7)
   ============================================================ */

.engagement-bar {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-md) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  margin: var(--space-xl) 0;
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  color: var(--color-text-secondary);
}

.clap-btn {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text-secondary);
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  padding: 0;
  transition: color var(--transition-fast);
}

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

.clap-btn:hover .clap-icon {
  transform: scale(1.15);
}

.clap-icon {
  display: inline-block;
  font-size: 24px;
  transition: transform var(--transition-fast);
}

.clap-icon.clapped {
  transform: scale(1.3);
}

.share-actions {
  position: relative;
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.share-icon {
  font-size: 18px;
  line-height: 1;
}

.save-icon {
  font-size: 18px;
  line-height: 1;
}

.share-label {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  line-height: 1;
}

.save-label {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  line-height: 1;
}

.share-menu {
  position: absolute;
  top: calc(100% + var(--space-sm));
  right: 0;
  min-width: 160px;
  display: flex;
  flex-direction: column;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-xs);
  z-index: 5;
}

.share-menu[hidden] {
  display: none;
}

.share-link {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  line-height: var(--leading-ui);
  color: var(--color-text-primary);
  background: none;
  border: none;
  text-align: left;
  padding: var(--space-sm) var(--space-sm);
  cursor: pointer;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.share-link:hover {
  background: var(--color-surface);
}

/* ============================================================
   Author Bio Section
   ============================================================ */

.author-bio {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--color-border);
}

.author-bio-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.author-bio-avatar {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  object-fit: cover;
}

.card-avatar,
.sidebar-pick-avatar,
.byline-avatar,
.author-bio-avatar {
  border: 1px solid var(--color-border);
  background:
    radial-gradient(circle at 50% 34%, var(--color-text-muted) 0 18%, transparent 19%),
    radial-gradient(ellipse at 50% 80%, var(--color-text-muted) 0 34%, transparent 35%),
    var(--color-surface);
}

.author-bio-name {
  font-family: var(--font-sans);
  font-size: 18px;
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}

.author-bio-text {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  color: var(--color-text-secondary);
  line-height: 1.6;
  max-width: 540px;
}

/* ============================================================
   More Articles Section
   ============================================================ */

.more-articles {
  padding: var(--space-2xl) 0;
}

.more-articles .card-meta,
.more-articles .card-footer,
.more-articles .card-text {
  text-align: left;
  justify-content: flex-start;
}

.more-articles-heading {
  font-family: var(--font-sans);
  font-size: var(--text-ui);
  font-weight: 700;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-xl);
}

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

.footer {
  border-top: 1px solid var(--color-border);
  padding: var(--space-2xl) var(--space-lg);
  font-family: var(--font-sans);
  font-size: var(--text-small);
  color: var(--color-text-secondary);
}

.footer-inner {
  max-width: var(--max-feed);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-links {
  display: flex;
  gap: var(--space-lg);
  flex-wrap: wrap;
  list-style: none;
}

.footer-links a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* ============================================================
   Accessibility
   ============================================================ */

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

/* Interactive minimum tap target */
button,
a,
[role="button"] {
  min-height: 44px;
  min-width: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* Override for inline text links */
p a,
.footer-links a,
.navbar-link,
.article-card,
.tag {
  min-height: unset;
  min-width: unset;
  display: inline;
}

.article-card {
  display: flex;
}

/* ============================================================
   Skeleton Loader
   ============================================================ */

@keyframes shimmer {

  0%,
  100% {
    opacity: 0.4;
  }

  50% {
    opacity: 1;
  }
}

.skeleton {
  background: var(--color-border);
  border-radius: var(--radius-sm);
  animation: shimmer 1.2s ease infinite;
}

/* ============================================================
   Responsive (§9)
   ============================================================ */

/* Tablet: 728–1080px */
@media (max-width: 1080px) {
  .feed-layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    display: none;
  }
}

/* Mobile: < 728px */
@media (max-width: 728px) {
  .hero-title {
    font-size: 36px;
  }

  .hero-subtitle {
    font-size: 20px;
  }

  .navbar-site-name {
    display: none;
  }

  .navbar-link:not(.btn-cta) {
    display: none;
  }

  .article-container {
    padding: var(--space-xl) var(--space-lg) var(--space-xl);
  }

  .article-title {
    font-size: 28px;
  }

  .article-body {
    font-size: 18px;
  }

  .article-body>p:first-of-type::first-letter {
    float: none;
    font-size: 1.6em;
    margin-right: 0;
    margin-top: 0;
  }

  .card-thumbnail {
    width: 100%;
    height: 180px;
    order: -1;
  }

  .card-body {
    flex-direction: column;
  }

  .feed-layout {
    padding: var(--space-xl) var(--space-lg);
  }
}