:root {
  --bg: #0b0d12;
  --card: #14171f;
  --line: #262b38;
  --text: #eef1f8;
  --muted: #8892a6;
  --ice: #dceaff;
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
}

body {
  display: flex;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, "Inter", "Segoe UI", sans-serif;
}

.sidebar {
  width: 260px;
  flex: none;
  padding: 24px 16px;
  border-right: 1px solid var(--line);
  overflow-y: auto;
}

.sidebar__eyebrow {
  margin: 0 0 4px;
  padding: 0 8px;
  font-size: 11px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--muted);
}

.sidebar__title {
  margin: 0 0 20px;
  padding: 0 8px;
  font-size: 18px;
}

.sidebar__list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.sidebar__item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  align-items: flex-start;
  padding: 10px 8px;
  border: none;
  border-radius: 10px;
  background: transparent;
  color: inherit;
  text-align: left;
  cursor: pointer;
}

.sidebar__item:hover { background: var(--card); }
.sidebar__item.is-active { background: var(--card); box-shadow: inset 2px 0 0 var(--ice); }

.sidebar__item-title { font-size: 14px; font-weight: 600; }
.sidebar__item-tagline { font-size: 12px; color: var(--muted); }

.sidebar__empty {
  padding: 0 8px;
  font-size: 13px;
  color: var(--muted);
}

.viewer {
  flex: 1;
  min-width: 0;
}

.viewer__frame {
  width: 100%;
  height: 100%;
  border: none;
  background: var(--bg);
}

@media (max-width: 680px) {
  body { flex-direction: column; }

  .sidebar {
    width: 100%;
    max-height: 40vh;
    border-right: none;
    border-bottom: 1px solid var(--line);
  }

  .viewer { flex: 1; min-height: 0; }
}