/**
 * Shared Activity shell — fixed chrome (back, title row, hear, footer).
 * Subject-specific content lives in .msh-activity-shell__body only.
 */

.msh-activity-shell {
    /* Default (no sidebar): centred at a comfortable reading width.
       When body.msh-sidebar-active is set (sidebar visible), main.css
       overrides both max-width and margin so the shell fills the right panel. */
    max-width: 760px;
    margin: 0.75rem auto 1.25rem;
    padding: 1rem 1.4rem 1.1rem;
    background: #fff;
    border-radius: 18px;
    box-shadow: 0 10px 32px rgba(15, 23, 42, 0.08);
    border: 1px solid rgba(148, 163, 184, 0.25);
}

.msh-activity-shell__back {
    margin-bottom: 0.65rem;
}

.msh-activity-shell .activity-title-row.msh-activity-shell__title-row {
    margin-bottom: 0.35rem;
    text-align: center;
}

.msh-activity-shell__title {
    margin: 0;
    font-size: clamp(1.35rem, 4vw, 1.75rem);
    font-weight: 800;
    color: #1d4ed8;
    line-height: 1.2;
}

.msh-activity-shell__hear-row {
    display: flex;
    justify-content: center;
    margin: 0.35rem 0 0.5rem;
}

.msh-activity-shell__hear {
    min-width: 10rem;
}

.msh-activity-shell__rule {
    border: none;
    border-top: 1px solid rgba(148, 163, 184, 0.35);
    margin: 0.65rem 0;
}

.msh-activity-shell__body {
    min-height: 4rem;
}

.msh-activity-shell__footer-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin-top: 0.25rem;
}

.msh-activity-shell__footer-nav button:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.msh-activity-shell__page-meta {
    color: #64748b;
    font-size: 0.95rem;
    font-weight: 600;
}

/* Hide duplicate hub back when inner shell back is used */
#skill-content:has(.msh-activity-shell) > #msh-sp-back-skills {
    display: none !important;
}