/* Hỗ trợ là lớp phụ, dùng thẻ/nút/màu chung của Student. */
.study-guidance { min-width: 0; padding: 16px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); }
.exam-preview-card > .study-guidance { margin: 16px 0; padding: 16px 0 0; border: 0; border-top: 1px solid var(--line); border-radius: 0; }
.study-guidance a:not(.button), .study-support-topics a, .study-source-link { color: var(--primary-dark); text-underline-offset: 3px; }
.study-guidance-header, .study-guidance-heading, .study-topic-row { display: flex; align-items: center; gap: 8px 12px; }
.study-guidance-header { flex-wrap: wrap; justify-content: space-between; }
.study-guidance-heading { flex: 1 1 220px; flex-wrap: wrap; min-width: 0; }
.study-guidance-heading > i { color: var(--primary-dark); }
.study-guidance h2 { scroll-margin-top: 76px; font-size: 1rem; line-height: 1.5; margin: 0; color: var(--text); }
.study-topic-count { font-size: .8125rem; color: var(--text-2); white-space: nowrap; }
.study-guidance .button { min-height: 36px; font-size: .8125rem; }
.study-guidance-header > .button { flex-shrink: 0; }
.study-guidance .study-ai-trigger { background: var(--primary-soft); border-color: var(--primary); color: var(--primary-dark); font-weight: 700; box-shadow: none; }
.study-guidance .study-ai-trigger:hover { background: var(--primary-dark); border-color: var(--primary-dark); color: #fff; }
.study-guidance .study-ai-trigger:focus-visible { outline: 2px solid var(--primary); outline-offset: 3px; }
.study-guidance summary, .study-question-support > summary, .study-composer > summary { display: flex; align-items: center; gap: .65rem; cursor: pointer; min-height: 44px; list-style: none; }
.study-guidance summary::-webkit-details-marker, .study-question-support > summary::-webkit-details-marker, .study-composer > summary::-webkit-details-marker { display: none; }
.study-guidance summary > .bi-chevron-down, .study-question-support > summary > .bi-chevron-down { margin-left: auto; font-size: .8rem; }
.study-guidance details[open] > summary > .bi-chevron-down, .study-question-support[open] > summary > .bi-chevron-down { transform: rotate(180deg); }
.study-topic { border-top: 1px solid var(--line); margin-top: 12px; padding-top: 12px; }
.study-topic-row { justify-content: space-between; flex-wrap: wrap; }
.study-topic h3 { display: flex; align-items: baseline; gap: 8px; flex: 1 1 160px; min-width: 0; margin: 0; color: var(--text); font-size: .875rem; line-height: 1.5; overflow-wrap: anywhere; }
.study-topic-number { flex: 0 0 2ch; color: var(--primary-dark); font-variant-numeric: tabular-nums; }
.study-topic-row > .button { flex-shrink: 0; }
.study-topic-resources { margin-top: 4px; }
.study-topic-resources > summary { width: fit-content; max-width: 100%; color: var(--primary-dark); font-size: .8125rem; font-weight: 600; }
.study-topic-content { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(220px, 100%), 1fr)); gap: 16px; padding: 8px 0; }
.study-topic-content > div { min-width: 0; }
.study-topic-content h4 { font-size: .8125rem; margin: 0 0 4px; color: var(--text); }
.study-topic-content a:not(.button) { display: block; padding: .35rem 0; }
.study-topic-content a { font-size: .875rem; overflow-wrap: anywhere; }
.study-guidance-more { margin-top: 12px; border-top: 1px solid var(--line); }
.study-guidance-more > summary { justify-content: flex-start; color: var(--primary-dark); font-size: .8125rem; font-weight: 600; }
.study-guidance-more > summary > .bi-chevron-down { margin-left: 0; }
.study-exam-guide { display: flex; align-items: center; gap: 8px; margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--line); font-size: .875rem; }
.study-guidance summary:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; border-radius: 4px; }
.study-question-support { border-top: 1px solid var(--border, #d6e2e8); padding: .15rem 1rem; font-size: .9rem; }
.study-question-support > summary { color: #0d7776; font-weight: 600; }
.study-support-content { padding: .4rem 0 .7rem; }
.study-support-ai { display: flex; flex-wrap: wrap; gap: .5rem; }
.study-support-ai .button { white-space: normal; text-align: left; }
.study-support-topics { list-style: none; margin: .65rem 0 0; padding: 0; }
.study-support-topics a { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: .55rem 0; }

[data-study-open][hidden] { display: none !important; }

/* Hướng dẫn soạn sẵn dùng details: đọc ngay, kể cả không có JavaScript. */
.study-preparation { border: 1px solid var(--border, #d5e2e7); border-radius: 10px; margin: 12px 0; background: #fff; }
.study-preparation > summary { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 14px; cursor: pointer; font-weight: 650; list-style: none; }
.study-preparation > summary span { display: flex; align-items: center; gap: 8px; }
.study-preparation > summary::-webkit-details-marker { display: none; }
.study-preparation[open] > summary > i { transform: rotate(180deg); }
.study-preparation-body { padding: 0 16px 16px; overflow-wrap: anywhere; }
.study-preparation-body h3 { margin: 18px 0 8px; font-size: 1rem; }
.study-preparation-body > small, .study-step-hint { display: block; color: #52657a; font-size: .82rem; margin: 8px 0; }
.study-solution-step { position: relative; padding: 8px 10px; margin: 4px -10px; border-radius: 8px; outline-offset: 2px; transition: background-color .15s; }
.study-solution-step:has(.study-step-ask[hidden]), .study-solution-step:not([data-solution-step]) { padding-bottom: 8px; }
.study-solution-step:hover, .study-solution-step:focus-within, .study-solution-step.is-selected { background: #e7f2f0; }
.study-step-ask { position: absolute; right: 8px; bottom: 4px; min-height: 32px; font-size: .8rem; padding: 4px 8px; opacity: 0; pointer-events: none; }
.study-solution-step:hover .study-step-ask, .study-solution-step:focus-within .study-step-ask, .study-solution-step.is-selected .study-step-ask { opacity: 1; pointer-events: auto; }
.study-step-ask:focus-visible { opacity: 1; }

@media (prefers-reduced-motion: reduce) { .study-solution-step { transition: none; } }

.study-solution-step:has(.study-step-ask:not([hidden])):is(:hover, :focus-within, .is-selected) { padding-bottom: 42px; }
.study-preparation-body mjx-container { max-width: 100%; overflow-x: auto; overflow-y: hidden; }
.study-preparation-body mjx-container[display="true"] { padding: 4px 0; }

/* Preview dùng cùng kiểu tab của trang học, không lồng thêm thẻ/tiêu đề. */
.learning-mode-tabs.study-preview-tabs { grid-template-columns: none; grid-auto-flow: column; grid-auto-columns: minmax(0, 1fr); margin: 0 0 18px; }
.study-preview-tabs, .study-preview-tabs a { scroll-margin-top: 76px; }
.study-guidance.study-guidance-compact { padding: 0; border: 0; background: transparent; }
.study-guidance-compact .study-preparation-body { padding: 0; }
[data-preview-panel][hidden] { display: none !important; }