:root {
  --bg: #0b0b0b;
  --fg: #e6e3d7;
  --accent: #e0b84b;
  --topbar-h: 56px;
  --subnav-h: 44px;
  --transition: .3s ease;
  --radius: 8px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0; padding: 0; height: 100%;
  background: var(--bg); color: var(--fg);
  font-family: 'Inter', system-ui, sans-serif;
  line-height: 1.6;
}

.topbar {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--topbar-h); display: flex; align-items: center;
  background: #111; border-bottom: 1px solid #222;
  padding: 0 1rem; z-index: 1000; gap: 1.5rem;
  overflow: hidden;
}

#menuBtn {
  background: none; border: 0; color: var(--accent);
  font-size: 1.4rem; cursor: pointer; font-weight: bold;
  line-height: 1; padding: 0; margin: 0;
  min-width: 2.5rem;
}

.primary-nav {
  display: flex; flex-wrap: wrap; gap: 1.5rem; align-items: center;
  overflow-x: auto;
  white-space: nowrap;
}

.primary-nav a {
  color: var(--accent); text-decoration: none;
  font-weight: 600; font-size: 1.1rem;
  transition: all var(--transition);
}

.primary-nav a:hover {
  text-shadow: 0 0 8px var(--accent);
}

/* NESTED HORIZON: Emergent Sub-Navigation with Animation */
.sub-nav {
  display: none;
  position: fixed;
  top: var(--topbar-h);
  left: 0; right: 0;
  height: var(--subnav-h);
  background: #0e0e0e;
  border-bottom: 1px solid #222;
  padding: 0 1rem;
  gap: 1rem;
  overflow-x: auto;
  white-space: nowrap;
  z-index: 950;
  align-items: center;
  opacity: 0;
  transform: translateY(-5px);
  transition: opacity var(--transition), transform var(--transition);
}

.sub-nav.visible {
  display: flex;
  opacity: 1;
  transform: translateY(0);
  animation: fadeSlideDown .3s ease forwards;
}

@keyframes fadeSlideDown {
  from { opacity: 0; transform: translateY(-5px); }
  to { opacity: 1; transform: translateY(0); }
}

.sub-nav a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: all var(--transition);
}

.sub-nav a:hover {
  text-shadow: 0 0 6px var(--accent);
}

#sidebar {
  position: fixed; top: calc(var(--topbar-h) + var(--subnav-h)); left: 0;
  width: 300px; bottom: 0; overflow: auto;
  background: #111; border-right: 1px solid #222;
  transform: translateX(-100%); transition: transform var(--transition);
  z-index: 900; padding: 1rem;
}

body.sidebar-open #sidebar { transform: translateX(0); }

.sidebar-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 1rem; padding-bottom: .5rem; border-bottom: 1px solid #222;
}

.sidebar-header h3 {
  margin: 0; font-size: 1.1rem; color: var(--accent);
}

.toggle-btn {
  background: none; border: 1px solid #333; color: var(--fg);
  padding: .25rem .5rem; border-radius: var(--radius);
  font-size: .8rem; cursor: pointer;
}

#postListSection { margin-bottom: 1rem; }

#postList {
  list-style: none; margin: 0; padding: 0;
}

#postList li {
  margin: .75rem 0; padding: .5rem 0;
  border-bottom: 1px dashed #222;
  transition: color var(--transition);
}

#postList a {
  color: var(--fg); text-decoration: none; font-weight: 500;
  display: block;
}

#postList a:hover { color: var(--accent); }

#postList small {
  display: block; font-size: .8rem; color: #888; margin-top: .25rem;
}

.filter-panel {
  background: #0a0a0a; border: 1px solid #222;
  border-radius: var(--radius); padding: .75rem;
  margin-top: 1rem;
}

.filter-panel summary {
  cursor: pointer; font-weight: 600; color: var(--accent);
  margin-bottom: .5rem; user-select: none;
}

.filter-controls {
  display: flex; flex-direction: column; gap: .75rem;
}

.filter-controls label {
  font-size: .85rem; color: var(--accent); margin-bottom: .25rem;
}

.filter-controls select, .filter-controls input {
  background: #111; color: var(--fg); border: 1px solid #333;
  padding: .5rem; border-radius: var(--radius); font-size: .9rem;
}

.filter-controls select[multiple] {
  height: 80px;
}

.content {
  margin-top: calc(var(--topbar-h) + var(--subnav-h)); margin-left: 0;
  transition: margin-left var(--transition), margin-top var(--transition);
  min-height: calc(100vh - var(--topbar-h) - var(--subnav-h));
  padding: 2rem 1rem;
}

@media (min-width: 1024px) {
  #sidebar { transform: translateX(0); top: calc(var(--topbar-h) + var(--subnav-h)); }
  .content { margin-left: 300px; }
}

.viewer > * {
  max-width: 720px; margin: auto; padding: 2rem 1rem;
  animation: fadeIn .4s ease-out;
}

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

.viewer iframe {
  width: 100%; height: calc(100vh - var(--topbar-h) - var(--subnav-h) - 80px);
  border: 0; border-radius: var(--radius); background: transparent;
  display: block;
}

/* === POP-OUT PREVIEW === */
.preview-header {
  text-align: right;
  background: rgba(224,184,75,0.08);
  border-bottom: 1px solid #333;
  padding: .4rem 1rem;
}
.popout-btn {
  background: none;
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 6px;
  padding: .25rem .6rem;
  font-size: .85rem;
  cursor: pointer;
  transition: all .25s ease;
}
.popout-btn:hover {
  background: var(--accent);
  color: var(--bg);
}