* { box-sizing: border-box; }
body.wbb-shell {
    margin: 0;
    background: #f8fafc;
    color: #0f172a;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
.wbb-shell-header {
    height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 28px;
    background: #fff;
    border-bottom: 1px solid #e5e7eb;
}
.wbb-shell-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    color: inherit;
    text-decoration: none;
}
.wbb-shell-brand small { display: block; color: #64748b; }
.wbb-shell-logo {
    display: grid;
    place-items: center;
    width: 42px;
    height: 42px;
    border-radius: 12px;
    color: #fff;
    background: var(--wbb-primary, #2563eb);
    font-weight: 700;
}
.wbb-shell-nav {
    display: flex;
    align-items: center;
    gap: 14px;
}
.wbb-shell-nav a { color: #0f172a; text-decoration: none; }
.wbb-shell-main { min-height: calc(100vh - 110px); padding: 1px 24px 48px; }
.wbb-shell-footer { text-align: center; padding: 18px; color: #64748b; }
.wbb-shell-message { max-width: 720px; margin: 48px auto; background: #fff; padding: 28px; border-radius: 16px; }