frontend/src/components/shell/header.css

.appheader {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(16px, 4vw, 32px);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
  backdrop-filter: blur(14px) saturate(1.2);
  border-bottom: 1px solid var(--hairline);
}
.appheader__brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: none;
  border: none;
  padding: 6px 0;
}
.appheader__mark {
  width: 26px;
  height: 26px;
  border-radius: 7px;
  background: var(--accent-gradient);
  display: grid;
  place-items: center;
  box-shadow: var(--glow-accent);
}
.appheader__mark-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.8);
}
.appheader__name {
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text);
}
.appheader__name-accent {
  color: var(--accent-b);
}

.appheader__right {
  display: flex;
  align-items: center;
  gap: 12px;
}
.appheader__theme {
  width: 38px;
  height: 38px;
  border-radius: var(--r-control);
  border: 1px solid var(--hairline-strong);
  background: var(--panel-elevated);
  color: var(--text-dim);
  font-size: 16px;
  display: grid;
  place-items: center;
  transition:
    color var(--dur-fast) var(--ease),
    border-color var(--dur-fast) var(--ease);
}
.appheader__theme:hover {
  color: var(--text);
  border-color: var(--accent-a);
}