nurse. (3) The term qualified opportunity zone means a census tract designated as a qualified opportunity zone under section 1400z–1(b)(1) as of the date of the enactment of this section. (c) Sunset No credit shall be allowed under subsection (a) for any taxable year beginning after the date that is 3 years after the date of the enactment of this section. . (b) Clerical amendment The table of section for subpart A of part IV of subchapter A of chapter 1 of such Code is amended by inserting after the item relating to section 25E the following new item: Sec. 25F. Credit for hired critical employees. . (c) Effective date The amendments made by this section shall apply to taxable years beginning after the date of the enactment of this section. 3. Permanent extension and modification of special rules for child tax credit (a) In general Section 24 of the Internal Revenue Code of 1986 is amended by striking subsections (a), (b), and (c) and inserting the following new subsections: (a) Allowance of credit There shall be allowed as a credit against the tax imposed by this chapter for the taxable year an amount equal to the sum of— (1) $3,500 for each qualifying child of the taxpayer ($4,500 in the case of a qualifying child who has not attained age 6 as of the close of the calendar year in which the taxable year of the taxpayer begins), and (2) in the case of any taxable year beginning before January 1, 2026, $500 for each qualifying dependent (other than a qualifying child) of the taxpayer. (b) Limitation based on adjusted gross income The amount of the credit allowable under subsection (a) shall be reduced (but not below zero) by $50 for each $1,000 (or fraction thereof) by which the taxpayer's modified adjusted gross income exceeds $400,000 in the case of a joint return ($200,000 in any other case). For purposes of the preceding sentence, the term “modified adjusted gross income” means adjusted gross income increased by any amount excluded from gross income under section 911, 931, or 933. (c) Qualifying child