.lesson-hero{background:linear-gradient(to right, var(--color-primary-ink), var(--color-primary), var(--color-primary-ink));color:var(--text-on-primary);position:relative;overflow:hidden}.lesson-hero__glow{pointer-events:none;background:var(--color-primary-subtle);opacity:.4;position:absolute;inset:0}.lesson-hero__chip{background:#ffffff2e;color:var(--text-on-primary)!important;border-color:#ffffff40!important}.lesson-hero__subtle{color:color-mix(in srgb, var(--text-on-primary) 70%, transparent)}.lesson-hero__panel{background:#ffffff1f;border-color:#ffffff24}.lesson-hero__track{color:#ffffff38}.lesson-hero__accent{color:var(--color-accent)}.lesson-sidebar{background:var(--color-surface);border-color:var(--border)}.lesson-item{background:var(--color-surface-muted);border-color:var(--border);color:var(--text-secondary)}.lesson-item:hover:not(:disabled){background:var(--color-surface-raised)}.lesson-item--active{background:var(--color-primary-subtle);border-color:var(--color-primary);color:var(--color-primary-ink)}.lesson-item--locked{background:var(--color-surface-muted);color:var(--text-muted);opacity:.65}.lesson-media-tabs{gap:var(--space-5);padding:var(--space-3) var(--space-4) 0;border-bottom:var(--a11y-border-width) solid var(--border-subtle);display:flex}.lesson-media-tab{font-size:var(--text-sm-size);padding:var(--space-2) 0 var(--space-3);color:var(--text-secondary);cursor:pointer;background:0 0;border:none;border-bottom:2px solid #0000;margin-bottom:-1px;font-weight:600}.lesson-media-tab:hover{color:var(--text-primary)}.lesson-media-tab--active{color:var(--color-primary-ink);border-bottom-color:var(--color-primary);font-weight:800}.lesson-media-dark{background:linear-gradient(to bottom right, var(--color-primary-ink), color-mix(in srgb, var(--color-primary-ink) 55%, black), var(--color-primary-ink));color:#fff}.lesson-media-dark-icon{background:color-mix(in srgb, var(--color-accent) 22%, transparent);color:var(--color-accent);border-color:color-mix(in srgb, var(--color-accent) 35%, transparent)}.lesson-media-frame{background:var(--color-primary-ink)}.lesson-media-frame__message{color:var(--text-inverse)}.lesson-tile--notes{background:var(--color-accent);border-color:var(--color-accent);color:var(--text-on-accent)}.lesson-tile--forum{background:var(--color-primary-subtle);border-color:color-mix(in srgb, var(--color-primary) 35%, var(--border));color:var(--color-primary-ink)}.lesson-tile--attachments{background:var(--color-secondary);border-color:var(--color-secondary);color:var(--text-primary)}.lesson-tile--notes:hover,.lesson-tile--forum:hover,.lesson-tile--attachments:hover{filter:brightness(.97)}.lesson-card-accent{border-color:color-mix(in srgb, var(--color-primary) 20%, var(--border))!important;border-inline-start:4px solid var(--color-primary)!important}.lesson-text-muted{color:var(--text-muted)}.lesson-text-primary{color:var(--text-primary)}.lesson-text-accent{color:var(--color-primary-ink)}.lesson-breadcrumb{color:var(--text-muted);font-size:.85rem}.lesson-heading{font-family:var(--font-ui);color:var(--text-primary)}.lesson-row{display:flex}.lesson-row-between{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1rem;display:flex}.lesson-stack{gap:.75rem;display:grid}.lesson-page-stack{gap:1.5rem;display:grid}.lesson-manage-bar{border-radius:var(--radius-sm);background:var(--color-accent-subtle);border-inline-start:4px solid var(--color-accent);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1rem;padding:.75rem 1rem;display:flex}.lesson-exam-row{justify-content:space-between;display:flex}.lesson-promo-card{border:2px solid var(--color-secondary);background:var(--color-surface);text-align:center;justify-items:center;gap:.75rem;padding:1.5rem;display:grid}.lesson-promo-card__title{color:var(--color-primary-ink);font-size:1.05rem;line-height:1.6}.lesson-promo-card__button{border-radius:var(--radius-full);background:var(--color-accent);min-height:44px;color:var(--text-on-accent);justify-content:center;align-items:center;padding:.65rem 1.5rem;font-weight:700;text-decoration:none;display:inline-flex}.lesson-promo-card__button:hover{background:var(--color-accent-hover)}.lesson-promo-card__button--disabled{opacity:.6;cursor:default}.lesson-promo-card__body{max-width:420px;color:var(--text-secondary);margin:0;line-height:1.8}