.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-direction: column;
    gap: 1rem;
    padding: 0.85rem 2rem;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.app-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--color-text);
    white-space: nowrap;
}

.header-user {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    font-size: 0.88rem;
    color: var(--color-text-muted);
    white-space: nowrap;
}

.header-user strong { color: var(--color-text); }

/* Haupt-Inhaltsbereiche */
.dashboard-content,
.detail-content {
    max-width: 1100px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

@media (max-width: 576px) {
    .app-header {
        padding: 0.75rem 1rem;
    }
    .dashboard-content,
    .detail-content { padding: 1rem; gap: 1rem; }
}

@media (min-width: 576px) {
    .app-header {
        flex-direction: row;
    }
}