.chapter-position{display:flex;align-items:center;gap:12px;margin-bottom:15px}.chapter-badge{gap:6px;padding:6px 14px;background:rgba(147,51,234,.15);color:var(--primary-light)}.chapter-badge,.chapter-completed-tag{display:inline-flex;align-items:center;border-radius:20px;font-size:.85rem;font-weight:500}.chapter-completed-tag{gap:4px;padding:6px 12px;background:rgba(34,197,94,.15);color:#22c55e}.chapter-navigation{display:grid;grid-template-columns:1fr auto 1fr;gap:20px;background:var(--card-bg);border:1px solid var(--border);border-radius:12px;padding:20px;margin-top:30px;margin-bottom:30px}.nav-item{display:flex}.nav-prev{justify-content:flex-start}.nav-next{justify-content:flex-end}.nav-link{display:flex;flex-direction:column;gap:6px;padding:12px 20px;border-radius:8px;text-decoration:none;transition:all .3s;max-width:280px}.nav-link:hover{background:rgba(147,51,234,.1)}.nav-link.disabled{opacity:.5;cursor:not-allowed}.nav-link.locked{background:rgba(239,68,68,.1)}.nav-link.locked:hover{background:rgba(239,68,68,.15)}.nav-direction{font-size:.85rem;color:var(--text-muted);display:flex;align-items:center;gap:6px}.nav-title{font-size:.95rem;color:#fff;font-weight:500;display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden}.btn-back-tutorial,.nav-center{display:flex;align-items:center}.btn-back-tutorial{padding:10px 20px;background:transparent;border:1px solid var(--border);color:var(--text-muted);border-radius:8px;text-decoration:none;font-size:.9rem;gap:8px;transition:all .3s}.btn-back-tutorial:hover{border-color:var(--primary);color:var(--primary-light)}.chapter-sidebar{position:sticky;top:90px;max-height:calc(100vh - 110px);overflow-y:auto}.sidebar-tutorial-title{color:#fff;text-decoration:none;display:flex;align-items:center;gap:8px;transition:color .2s}.sidebar-tutorial-title:hover{color:var(--primary-light)}.chapter-list-sidebar{display:flex;flex-direction:column;gap:4px;margin-bottom:15px;max-height:400px;overflow-y:auto}.chapter-item{display:flex;align-items:center;gap:10px;padding:10px 12px;border-radius:6px;text-decoration:none;color:var(--text-muted);font-size:.9rem;transition:all .2s}.chapter-item:hover{background:hsla(0,0%,100%,.05);color:#fff}.chapter-item.active{background:rgba(147,51,234,.15);color:var(--primary-light);border-left:3px solid var(--primary)}.chapter-item.completed .chapter-order{color:#22c55e}.chapter-order{font-weight:600;color:var(--text-dim);min-width:24px}.chapter-title-text{flex:1;display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden}.chapter-check{color:#22c55e;font-size:.85rem}.sidebar-progress{padding-top:15px;border-top:1px solid var(--border);font-size:.85rem;color:var(--text-muted)}.mini-progress-bar{height:4px;background:var(--border);border-radius:2px;margin-top:8px;overflow:hidden}.mini-progress-fill{height:100%;background:linear-gradient(90deg,var(--primary),#ec4899);border-radius:2px;transition:width .5s ease}.mark-complete-section{padding:20px 40px;border-top:1px solid var(--border);display:flex;justify-content:center}.btn-mark-complete{padding:12px 30px;background:var(--primary);color:#fff;border:none;border-radius:8px;font-size:.95rem;font-weight:600;cursor:pointer;display:flex;align-items:center;gap:8px;transition:all .3s}.btn-mark-complete:hover:not(:disabled){background:var(--primary-dark);box-shadow:0 5px 20px rgba(147,51,234,.4)}.btn-mark-complete.completed{background:#22c55e;cursor:default}.btn-mark-complete:disabled{opacity:.7}@media (max-width:1023px){.chapter-navigation{grid-template-columns:1fr;gap:15px}.nav-center{order:-1}.nav-center,.nav-next,.nav-prev{justify-content:center}.nav-link{max-width:100%}}@media (max-width:640px){.chapter-navigation{padding:15px}.mark-complete-section{padding:15px 20px}.btn-mark-complete{width:100%;justify-content:center}}