Когда блок схлопывается по ширине контента и уменьшается.
.subject_id_biology
.subject_id_chemistry
.subject_id_computer-science
.subject_id_english-language
.subject_id_history
.subject_id_literature
.subject_id_math
.subject_id_physics
.subject_id_russian-language
.subject_id_sociology