*{ box-sizing: border-box; }

body{
  margin: 0;
  font-family: system-ui, -apple-system, Arial, sans-serif;
  background: #0b1220;
  color: rgba(255,255,255,.92);
}

.head{
  padding: 18px 18px 10px;
}

.head h1{
  margin: 0 0 6px;
  font-size: 20px;
}

.head p{
  margin: 0;
  color: rgba(255,255,255,.72);
  line-height: 1.6;
  max-width: 900px;
}

.layout{
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 14px;
  padding: 14px 18px 18px;
}

.menu{
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.14);
  border-radius: 10px;
  padding: 10px;
  display: grid;
  gap: 8px;
}

.tab{
  width: 100%;
  text-align: left;
  padding: 10px 12px;
  border-radius: 10px;
  background: rgba(255,255,255,.08);
  border: 1px solid rgba(255,255,255,.14);
  color: rgba(255,255,255,.88);
  cursor: pointer;
}

.tab.is-active{
  background: rgba(180,106,255,.22);
  border-color: rgba(180,106,255,.35);
}

.viewer{
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.14);
  border-radius: 10px;
  padding: 10px;
}

.frame{
  width: 100%;
  height: 560px;
  border: 0;
  border-radius: 8px;
  background: #fff;
}

.hint{
  margin: 10px 0 0;
  color: rgba(255,255,255,.58);
  font-size: 13px;
  line-height: 1.6;
}