@font-face {
  font-family: 'Inter';
  src: url('inter-latin.woff2') format('woff2');
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

:root {
  --color-blue: #1d9bf0;
  --color-blue-hover: #1a8cd8;
  --color-blue-subtle: rgba(29, 155, 240, 0.1);
  --color-bg: #f7f9fa;
  --color-border: #eff3f4;
  --color-ink: #0f1419;
  --color-muted: #536471;
  --color-white: #ffffff;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-pill: 9999px;
  --focus-ring: 0 0 0 2px var(--color-white), 0 0 0 4px var(--color-blue);
  --transition: 0.15s ease;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-ink);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  min-width: 0;
}
a { color: inherit; text-decoration: none; }
button, input { font-family: inherit; font-size: inherit; color: inherit; border: none; background: none; }
button { cursor: pointer; }
h1, h2, h3, p { overflow-wrap: break-word; }
[hidden] { display: none !important; }
:focus-visible { outline: none; box-shadow: var(--focus-ring); }

.skip-link {
  position: absolute; top: -100px; left: 16px; background: var(--color-blue); color: var(--color-white);
  padding: 8px 16px; border-radius: var(--radius-sm); z-index: 1000; font-weight: 700;
}
.skip-link:focus { top: 16px; }

.icon {
  width: 24px; height: 24px; stroke: currentColor; stroke-width: 2;
  stroke-linecap: round; stroke-linejoin: round; fill: none; flex-shrink: 0;
}

/* APP LAYOUT */
.app-layout {
  max-width: 1250px; margin: 0 auto; display: grid;
  grid-template-columns: 240px minmax(0, 650px) 330px; justify-content: center; min-height: 100vh;
}
main.main-column {
  background: var(--color-white); border-left: 1px solid var(--color-border);
  border-right: 1px solid var(--color-border); min-width: 0; width: 100%;
}

/* LEFT SIDEBAR */
aside.left-sidebar {
  position: sticky; top: 0; height: 100dvh; display: flex; flex-direction: column;
  justify-content: space-between; padding: 16px 12px; overflow-y: auto;
}
.sidebar-top { display: flex; flex-direction: column; }
a.brand {
  display: inline-flex; align-items: center; gap: 12px; font-size: 1.25rem;
  font-weight: 800; color: var(--color-ink); padding: 8px 12px; border-radius: var(--radius-pill); min-height: 44px;
}
a.brand .icon { color: var(--color-blue); stroke: var(--color-blue); }
a.brand:hover { background-color: var(--color-blue-subtle); }
nav.side-nav { display: flex; flex-direction: column; gap: 4px; margin-top: 16px; }
.nav-link {
  display: inline-flex; align-items: center; gap: 16px; padding: 10px 14px;
  border-radius: var(--radius-pill); font-size: 1.1rem; font-weight: 600;
  color: var(--color-ink); min-height: 44px; transition: background-color var(--transition);
}
.nav-link:hover { background-color: rgba(15, 20, 25, 0.08); }
.nav-link.active { font-weight: 800; color: var(--color-blue); }
.nav-link.active .icon { stroke: var(--color-blue); }
.sidebar-bottom { margin-top: auto; display: flex; flex-direction: column; gap: 12px; }
.signup-card {
  background: var(--color-white); border: 1px solid var(--color-border);
  border-radius: var(--radius-md); padding: 16px; display: flex; flex-direction: column; gap: 8px;
}
.signup-card h3 { font-size: 0.95rem; font-weight: 800; }
.signup-card p { font-size: 0.82rem; color: var(--color-muted); }
.sidebar-note { font-size: 0.75rem; color: var(--color-muted); padding: 0 4px; }

/* BUTTONS, BADGES & NOTICES */
.btn {
  display: inline-flex; align-items: center; justify-content: center; font-weight: 700;
  border-radius: var(--radius-pill); min-height: 44px; padding: 0 20px; font-size: 0.92rem;
  text-align: center; transition: opacity var(--transition), background-color var(--transition);
}
.btn:hover { opacity: 0.9; }
.btn-blue { background: var(--color-blue); color: var(--color-white); }
.btn-white { background: var(--color-white); color: var(--color-ink); }
.btn-small { min-height: 36px; padding: 0 14px; font-size: 0.82rem; }
.btn-outline { border: 1px solid var(--color-border); color: var(--color-ink); }
.btn-outline:hover { background-color: rgba(15, 20, 25, 0.05); }
.btn-dark { background: var(--color-ink); color: var(--color-white); }
.prototype-badge {
  display: inline-block; font-size: 0.7rem; font-weight: 600; color: var(--color-muted);
  background: rgba(83, 100, 113, 0.12); padding: 2px 8px; border-radius: var(--radius-pill);
}
.notice {
  background: var(--color-blue-subtle); color: var(--color-blue); font-size: 0.82rem;
  font-weight: 600; padding: 8px 16px; border-radius: var(--radius-sm); margin: 12px 16px;
}

/* TOPBAR & MOBILE HEADER */
.mobile-header {
  display: none; position: sticky; top: 0; z-index: 90; background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px); border-bottom: 1px solid var(--color-border);
  padding: 8px 16px; align-items: center; justify-content: space-between; height: 52px;
}
header.topbar {
  position: sticky; top: 0; z-index: 80; background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px); border-bottom: 1px solid var(--color-border);
  padding: 10px 16px; display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.topbar .page-title { font-size: 1.25rem; font-weight: 800; line-height: 1.2; }
.topbar .page-subtitle { font-size: 0.8rem; color: var(--color-muted); display: block; }
.account-actions { display: flex; align-items: center; gap: 8px; }

/* HERO */
.hero {
  background: linear-gradient(135deg, #1d9bf0 0%, #7856ff 100%); color: var(--color-white);
  padding: 24px 20px; position: relative; overflow: hidden;
  display: flex; flex-direction: column; justify-content: center;
}
.hero::after {
  content: ""; position: absolute; top: -40px; right: -40px; width: 180px; height: 180px;
  border-radius: 50%; background: rgba(255, 255, 255, 0.08); pointer-events: none;
}
.hero-eyebrow { font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; opacity: 0.9; margin-bottom: 4px; }
.hero h1 { font-size: 1.45rem; font-weight: 800; line-height: 1.25; margin-bottom: 6px; }
.hero p { font-size: 0.88rem; opacity: 0.92; margin-bottom: 14px; max-width: 500px; }
.hero-actions { display: flex; align-items: center; gap: 12px; }
.hero-link { font-size: 0.88rem; font-weight: 600; text-decoration: underline; color: var(--color-white); }

/* FEED TABS, TOOLS & FILTER CHIPS */
.feed-tabs { display: flex; border-bottom: 1px solid var(--color-border); }
.tab {
  flex: 1; text-align: center; padding: 14px 16px; font-weight: 600; font-size: 0.95rem;
  color: var(--color-muted); position: relative; min-height: 44px; display: flex;
  align-items: center; justify-content: center;
}
.tab:hover { background-color: rgba(15, 20, 25, 0.04); }
.tab.active { color: var(--color-ink); font-weight: 700; }
.tab.active::after {
  content: ""; position: absolute; bottom: 0; left: 50%; transform: translateX(-50%);
  width: 56px; height: 4px; border-radius: var(--radius-pill); background-color: var(--color-blue);
}
.feed-tools {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 16px; border-bottom: 1px solid var(--color-border);
}
.feed-tools h2 { font-size: 1rem; font-weight: 700; }
.feed-tools span { font-size: 0.8rem; color: var(--color-muted); }
.filter-chips {
  display: flex; gap: 8px; padding: 10px 16px; border-bottom: 1px solid var(--color-border);
  overflow-x: auto; white-space: nowrap; scrollbar-width: none;
}
.filter-chips::-webkit-scrollbar { display: none; }
.chip {
  padding: 6px 14px; border-radius: var(--radius-pill); background: var(--color-bg);
  border: 1px solid var(--color-border); font-size: 0.82rem; font-weight: 600;
  color: var(--color-muted); min-height: 36px; display: inline-flex; align-items: center;
}
.chip:hover { background: #eff3f4; color: var(--color-ink); }
.chip.active { background: var(--color-ink); color: var(--color-white); border-color: var(--color-ink); }

/* FEED POSTS (BORDER-BOTTOM TIMELINE) */
.feed-list { display: flex; flex-direction: column; }
article.post {
  display: flex; gap: 12px; padding: 14px 16px; border-bottom: 1px solid var(--color-border);
  transition: background-color var(--transition);
}
article.post:hover { background-color: rgba(15, 20, 25, 0.015); }
.avatar {
  width: 40px; height: 40px; border-radius: 50%; display: flex; align-items: center;
  justify-content: center; font-weight: 700; font-size: 0.9rem; color: var(--color-white); flex-shrink: 0;
}
.avatar-blue { background: #1d9bf0; }
.avatar-purple { background: #7856ff; }
.avatar-orange { background: #ff7a00; }
.avatar-green { background: #00ba7c; }
.avatar svg { width: 20px; height: 20px; }
.avatar.small { width: 32px; height: 32px; font-size: 0.8rem; }
.post-body { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 6px; }
.post-meta { display: flex; align-items: center; gap: 6px; font-size: 0.88rem; flex-wrap: wrap; }
.post-meta strong { color: var(--color-ink); }
.post-meta .handle { color: var(--color-muted); }
.meta-dot::before { content: "·"; color: var(--color-muted); }
.post-meta .kind {
  font-size: 0.75rem; background: var(--color-bg); border: 1px solid var(--color-border);
  padding: 1px 6px; border-radius: var(--radius-pill); color: var(--color-muted);
}
h2.post-title { font-size: 1rem; font-weight: 700; line-height: 1.3; }
h2.post-title a:hover { text-decoration: underline; }
.post-copy { font-size: 0.92rem; line-height: 1.45; color: var(--color-ink); }
.link-card {
  display: flex; align-items: center; gap: 12px; border: 1px solid var(--color-border);
  border-radius: var(--radius-md); padding: 10px 14px; margin-top: 6px; transition: background-color var(--transition);
}
.link-card:hover { background-color: var(--color-bg); }
.link-card-icon { display: flex; align-items: center; justify-content: center; color: var(--color-blue); }
.link-card div { display: flex; flex-direction: column; min-width: 0; }
.link-card strong { font-size: 0.88rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.link-card span { font-size: 0.78rem; color: var(--color-muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.post-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 4px; }
.post-tags a { color: var(--color-blue); font-size: 0.85rem; }
.post-tags a:hover { text-decoration: underline; }
.post-actions { display: flex; justify-content: space-between; max-width: 420px; margin-top: 6px; }
.action {
  display: inline-flex; align-items: center; gap: 6px; color: var(--color-muted); font-size: 0.82rem;
  min-height: 44px; min-width: 44px; padding: 4px 8px; border-radius: var(--radius-pill);
  transition: color var(--transition), background-color var(--transition);
}
.action .icon { width: 18px; height: 18px; }
.action:hover { color: var(--color-blue); background-color: var(--color-blue-subtle); }

/* FEED INTRO, PROFILE, ARTICLE, TOPICS & EMPTY STATE */
.feed-intro { padding: 14px 16px; border-bottom: 1px solid var(--color-border); }
.feed-intro p { color: var(--color-muted); font-size: 0.92rem; }
.profile-cover { height: 140px; background: linear-gradient(135deg, #1d9bf0, #7856ff); }
.profile-summary { padding: 0 16px 16px; border-bottom: 1px solid var(--color-border); position: relative; }
.profile-avatar.large {
  width: 72px; height: 72px; border: 3px solid var(--color-white); border-radius: 50%;
  margin-top: -36px; margin-bottom: 8px; font-size: 1.5rem; background: var(--color-blue);
  color: var(--color-white); display: flex; align-items: center; justify-content: center;
}
.profile-summary h1 { font-size: 1.3rem; font-weight: 800; }
.profile-summary p { font-size: 0.9rem; color: var(--color-ink); margin-top: 4px; }
.profile-stats { display: flex; gap: 16px; margin-top: 10px; font-size: 0.85rem; color: var(--color-muted); }
.profile-stats strong { color: var(--color-ink); }
.article-content { padding: 20px 16px; line-height: 1.6; }
.article-byline { font-size: 0.85rem; color: var(--color-muted); margin-bottom: 16px; display: block; }
.article-content h2 { font-size: 1.25rem; font-weight: 700; margin: 20px 0 10px; }
.article-lede { font-size: 1.1rem; color: var(--color-ink); margin-bottom: 16px; font-weight: 500; }
.article-callout {
  border-left: 3px solid var(--color-blue); background: var(--color-bg); padding: 12px 16px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0; margin: 16px 0; font-size: 0.92rem;
}
.topic-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 12px; padding: 16px; }
.topic-card {
  padding: 14px; background: var(--color-bg); border: 1px solid var(--color-border);
  border-radius: var(--radius-md); font-weight: 700; font-size: 0.95rem;
  transition: border-color var(--transition), transform var(--transition);
}
.topic-card:hover { border-color: var(--color-blue); transform: translateY(-1px); }
.empty-state { padding: 48px 24px; text-align: center; color: var(--color-muted); }

/* RIGHT SIDEBAR */
aside.right-sidebar {
  position: sticky; top: 20px; height: fit-content; max-height: calc(100dvh - 40px);
  padding: 16px 20px; overflow-y: auto;
}
.search-box { position: relative; margin-bottom: 16px; }
.search-box input {
  width: 100%; background-color: #eff3f4; border: 1px solid transparent; padding: 10px 16px 10px 44px;
  border-radius: var(--radius-pill); font-size: 0.9rem; transition: all var(--transition);
}
.search-box input:focus { background-color: var(--color-white); border-color: var(--color-blue); }
.search-box .icon {
  position: absolute; left: 14px; top: 50%; transform: translateY(-50%);
  color: var(--color-muted); width: 18px; height: 18px;
}
.search-result-count { font-size: 0.8rem; color: var(--color-muted); padding: 0 4px 8px; }
.widget { background: var(--color-bg); border-radius: var(--radius-md); padding: 16px; margin-bottom: 16px; }
.widget h2 { font-size: 1.1rem; font-weight: 800; margin-bottom: 12px; }
.widget p { font-size: 0.85rem; color: var(--color-muted); margin-bottom: 12px; }
.widget .btn { width: 100%; }
.suggestion { display: flex; align-items: center; gap: 10px; padding: 8px 0; }
.suggestion-text { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.suggestion-text strong { font-size: 0.88rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.suggestion-text span { font-size: 0.78rem; color: var(--color-muted); }
.follow-link {
  background: var(--color-ink); color: var(--color-white); font-size: 0.8rem; font-weight: 700;
  padding: 6px 14px; border-radius: var(--radius-pill); min-height: 32px; display: inline-flex; align-items: center;
}
.follow-link:hover { opacity: 0.9; }
.topic-row { display: flex; align-items: center; justify-content: space-between; padding: 8px 0; }
.topic-row div { display: flex; flex-direction: column; }
.topic-row strong { font-size: 0.9rem; }
.topic-row span { font-size: 0.78rem; color: var(--color-muted); }
.topic-row a { color: var(--color-blue); font-size: 0.82rem; font-weight: 600; }
.about-list { list-style: none; display: flex; flex-direction: column; gap: 8px; font-size: 0.85rem; color: var(--color-muted); }
footer.legal-links { display: flex; flex-wrap: wrap; gap: 4px 8px; padding: 0 12px; font-size: 0.75rem; color: var(--color-muted); }
footer.legal-links a:hover { text-decoration: underline; }

/* MOBILE NAVIGATION & TOAST */
.mobile-nav {
  display: none; position: fixed; bottom: 0; left: 0; right: 0; height: 60px;
  background: rgba(255, 255, 255, 0.95); backdrop-filter: blur(12px);
  border-top: 1px solid var(--color-border); z-index: 100; justify-content: space-around; align-items: center;
}
.mobile-nav .nav-link { flex-direction: column; gap: 2px; padding: 6px; font-size: 0.7rem; }
.mobile-nav .nav-link .icon { width: 22px; height: 22px; }
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%); background: var(--color-ink);
  color: var(--color-white); padding: 10px 20px; border-radius: var(--radius-pill); font-size: 0.88rem;
  font-weight: 600; z-index: 200; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* RESPONSIVE BREAKPOINTS */
@media (max-width: 1099px) {
  .app-layout { grid-template-columns: 240px minmax(0, 650px); }
  aside.right-sidebar { display: none; }
}

@media (max-width: 850px) {
  .app-layout { grid-template-columns: 76px minmax(0, 650px); }
  aside.left-sidebar { width: 76px; padding: 12px 8px; align-items: center; }
  aside.left-sidebar .brand span, nav.side-nav .nav-link span, .sidebar-bottom { display: none; }
  a.brand { padding: 10px; justify-content: center; }
  .nav-link { padding: 12px; justify-content: center; width: 48px; height: 48px; }
}

@media (max-width: 600px) {
  .app-layout { grid-template-columns: minmax(0, 1fr); padding-bottom: 60px; }
  aside.left-sidebar { display: none; }
  .mobile-header { display: flex; }
  .mobile-nav { display: flex; }
  .toast { bottom: 72px; }
  main.main-column { border-left: none; border-right: none; }
}

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