/* Tùy chỉnh thanh cuộn siêu mượt */
.custom-scrollbar::-webkit-scrollbar { width: 6px; height: 6px; }
.custom-scrollbar::-webkit-scrollbar-track { background: transparent; }
.custom-scrollbar::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 10px; }
.custom-scrollbar::-webkit-scrollbar-thumb:hover { background: #94a3b8; }
.custom-scrollbar { -ms-overflow-style: none; scrollbar-width: thin; }

/* TAB GÓI HỌC (PILLS) */
.tab-pill { background-color: white; color: #64748b; border: 1px solid #e2e8f0; padding: 12px 24px; border-radius: 50px; cursor: pointer; white-space: nowrap; font-size: 14px; font-weight: 700; transition: all 0.2s ease; box-shadow: 0 2px 4px rgba(0,0,0,0.02); display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.tab-pill:hover { background-color: #f8fafc; border-color: #cbd5e1; color: #334155; }
.tab-pill.active { background-color: #3b82f6; color: white; border-color: #3b82f6; box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3); }
.tab-pill.active i { color: white; }

/* PLAYLIST ITEM */
.playlist-item { display: flex; align-items: center; gap: 12px; background-color: #f8fafc; border: 1px solid transparent; padding: 12px; border-radius: 12px; cursor: pointer; transition: all 0.2s ease; }
.playlist-item:hover { background-color: #eff6ff; border-color: #dbeafe; }
.playlist-item.active { background-color: #eff6ff; border-color: #3b82f6; box-shadow: 0 2px 8px rgba(59, 130, 246, 0.15); }

.playlist-num { width: 32px; height: 32px; background-color: white; border: 1px solid #e2e8f0; color: #94a3b8; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: bold; font-size: 13px; flex-shrink: 0; transition: 0.2s; }
.playlist-item.active .playlist-num { background-color: #3b82f6; color: white; border-color: #3b82f6; }

.playlist-title { flex-grow: 1; color: #334155; font-size: 14px; font-weight: 600; line-height: 1.4; }
.playlist-item.active .playlist-title { color: #1d4ed8; }

.playlist-icon { color: transparent; font-size: 14px; transition: 0.2s; flex-shrink: 0; }
.playlist-item:hover .playlist-icon { color: #bfdbfe; }
.playlist-item.active .playlist-icon { color: #3b82f6; }

/* --- TRẠNG THÁI TIẾN ĐỘ XEM VIDEO --- */

/* 1. Chưa xem (Xanh nhạt) */
.playlist-item.status-new { border: 1px solid #bfdbfe; }
.playlist-item.active.status-new { border-color: #3b82f6; box-shadow: 0 2px 8px rgba(59, 130, 246, 0.25); background-color: #eff6ff;}

/* 2. Dưới 50% (Đỏ) */
.playlist-item.status-learning { border: 1px solid #fca5a5; background-color: #fef2f2; } 
.playlist-item.status-learning .playlist-num { color: #ef4444; border-color: #fca5a5; }
.playlist-item.status-learning .playlist-icon { color: #fca5a5; }

/* Trạng thái Đang xem bài Đỏ */
.playlist-item.active.status-learning { border-color: #ef4444; box-shadow: 0 2px 8px rgba(239, 68, 68, 0.25); background-color: #fef2f2; }
.playlist-item.active.status-learning .playlist-num { background-color: #ef4444; color: white; border-color: #ef4444; }
.playlist-item.active.status-learning .playlist-title { color: #b91c1c; }
.playlist-item.active.status-learning .playlist-icon { color: #ef4444; }


/* 3. Từ 51% - 85% (Vàng) */
.playlist-item.status-halfway { border: 1px solid #fde047; background-color: #fefce8; } 
.playlist-item.status-halfway .playlist-num { color: #eab308; border-color: #fde047; }
.playlist-item.status-halfway .playlist-icon { color: #fde047; }

/* Trạng thái Đang xem bài Vàng */
.playlist-item.active.status-halfway { border-color: #eab308; box-shadow: 0 2px 8px rgba(234, 179, 8, 0.25); background-color: #fefce8; }
.playlist-item.active.status-halfway .playlist-num { background-color: #eab308; color: white; border-color: #eab308; }
.playlist-item.active.status-halfway .playlist-title { color: #a16207; }
.playlist-item.active.status-halfway .playlist-icon { color: #eab308; }


/* 4. Trên 85% (Xanh lá) */
.playlist-item.status-completed { border: 1px solid #86efac; background-color: #f0fdf4; } 
.playlist-item.status-completed .playlist-num { color: #22c55e; border-color: #86efac; background-color: #dcfce7; }
.playlist-item.status-completed .playlist-icon { color: #22c55e; }

/* Trạng thái Đang xem bài Xanh lá */
.playlist-item.active.status-completed { border-color: #22c55e; box-shadow: 0 2px 8px rgba(34, 197, 94, 0.25); background-color: #f0fdf4;}
.playlist-item.active.status-completed .playlist-num { background-color: #22c55e; color: white; border-color: #22c55e; }
.playlist-item.active.status-completed .playlist-title { color: #15803d; }
.playlist-item.active.status-completed .playlist-icon { color: #22c55e; }

/* Highlight phát sáng khi đang chọn đúng bài đó */
.playlist-item.active.status-new { border-color: #3b82f6; box-shadow: 0 2px 8px rgba(59, 130, 246, 0.25); background-color: #eff6ff;}
.playlist-item.active.status-learning { border-color: #ef4444; box-shadow: 0 2px 8px rgba(239, 68, 68, 0.25); }
.playlist-item.active.status-halfway { border-color: #eab308; box-shadow: 0 2px 8px rgba(234, 179, 8, 0.25); }
.playlist-item.active.status-completed { border-color: #22c55e; box-shadow: 0 2px 8px rgba(34, 197, 94, 0.25); }

/* QUILL CONTENT - BÀI TẬP */
.quill-content h1, .quill-content h2 { font-size: 1.1rem; font-weight: bold; margin-bottom: 10px; color: #1e293b; }
.quill-content p { font-size: 15px; color: #475569; line-height: 1.7; margin-bottom: 12px; }
.quill-content ul, .quill-content ol { list-style: decimal inside; margin-bottom: 15px; font-size: 15px; color: #475569; }
.quill-content li { margin-bottom: 6px; }
.quill-content img { max-width: 100%; border-radius: 8px; margin: 10px 0; }
/* ================= SCORE BUTTONS ================= */
.score-btn {
    width: 48px; height: 48px;
    border-radius: 12px;
    background-color: white;
    border: 2px solid #e2e8f0;
    color: #64748b;
    font-weight: 800;
    font-size: 18px;
    display: flex; align-items: center; justify-content: center;
    cursor: pointer; 
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}
.score-btn:hover { border-color: #cbd5e1; transform: translateY(-3px); box-shadow: 0 4px 8px rgba(0,0,0,0.05); }

/* Màu theo Thang điểm */
.score-btn.active-red { background-color: #ef4444; border-color: #ef4444; color: white; box-shadow: 0 4px 12px rgba(239, 68, 68, 0.3); transform: translateY(-2px); }
.score-btn.active-yellow { background-color: #f59e0b; border-color: #f59e0b; color: white; box-shadow: 0 4px 12px rgba(245, 158, 11, 0.3); transform: translateY(-2px); }
.score-btn.active-green { background-color: #10b981; border-color: #10b981; color: white; box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3); transform: translateY(-2px); }