* { box-sizing: border-box; }
:root { color-scheme: light; --course-control-radius: 12px; --course-panel-radius: 18px; }
:root[data-theme="dark"] { color-scheme: dark; }
input::placeholder { color: var(--text-tertiary); opacity: 1; }
dialog::backdrop { background: color-mix(in srgb, var(--bg-primary) 55%, transparent); }
body { margin: 0; display: grid; grid-template-columns: clamp(250px, 29.5vw, 560px) minmax(0, 1fr); height: 100dvh; background: var(--bg-primary); color: var(--text-primary); font-family: var(--font-family, Inter, system-ui, sans-serif); font-size: .875rem; }
button, input, select { font: inherit; }
button { cursor: pointer; padding: 9px 12px; border: 1px solid var(--border); border-radius: var(--course-control-radius); color: inherit; background: var(--bg-secondary); }
button:hover, button[aria-current="true"] { background: var(--bg-tertiary); }
button:focus-visible, input:focus-visible, select:focus-visible { outline: 2px solid #6b8cff; outline-offset: 2px; }
.course-sidebar { display: flex; flex-direction: column; min-height: 0; padding: 18px 10px 0; }
.course-brand { display: flex; align-items: center; gap: 11px; min-height: 30px; margin: 0 5px 20px; font-weight: 700; color: var(--text-primary); }
.course-brand-mark { display: block; width: 20px; height: 20px; background: var(--course-accent); -webkit-mask: url('../images/LSlogo.svg') center / contain no-repeat; mask: url('../images/LSlogo.svg') center / contain no-repeat; }
.course-identity { position: relative; display: flex; align-items: center; gap: 10px; color: var(--text-secondary); padding: 0 8px; }
.course-identity > span:first-child { font-size: 1.25rem; }
h1 { font-size: .8125rem; font-weight: 400; overflow: hidden; white-space: nowrap; text-overflow: ellipsis; margin: 0; }
#courseSort { margin-left: auto; padding: 5px 8px; border: 0; border-radius: 8px; background: transparent; color: var(--text-secondary); font-size: .6875rem; font-weight: 600; }
#courseSort svg { display: block; width: 18px; height: 18px; }
#courseSort:hover, #courseSort:focus-visible { background: var(--bg-tertiary); color: var(--text-primary); }
.course-sort-menu { position: absolute; top: calc(100% + 8px); right: 8px; z-index: 30; min-width: 140px; padding: 6px; border: 1px solid var(--border); border-radius: 14px; background: var(--surface-glass-strong); box-shadow: 0 8px 28px #0002; }
.course-sort-menu button { display: block; width: 100%; padding: 9px 10px; border: 0; border-radius: 9px; background: transparent; text-align: left; font-size: .75rem; }
.course-sort-menu button:hover { background: var(--bg-hover); }
h2 { font-size: .8125rem; font-weight: 600; margin: 0; }
#loadCourse { display: inline-flex; align-items: center; gap: 8px; flex: 0 0 auto; margin: 0 0 0 -6px; padding: 6px; border: 1px solid transparent; border-radius: var(--course-control-radius); background: transparent; color: var(--text-secondary); font-size: .875rem; }
#loadCourse svg { width: 20px; height: 20px; }
#loadCourse:hover, #loadCourse:focus-visible { background: var(--bg-tertiary); border-color: var(--border); color: var(--text-primary); }
.course-search { position: relative; display: flex; align-items: center; margin: 12px 0 16px; height: 38px; min-height: 38px; flex: 0 0 38px; }
.course-search > button { display: grid; place-items: center; width: 34px; height: 34px; padding: 6px; border: 1px solid transparent; border-radius: 10px; background: transparent; color: var(--text-secondary); }
.course-search > button:hover, .course-search > button:focus-visible { background: var(--bg-tertiary); color: var(--text-primary); }
.course-search > button svg { width: 18px; height: 18px; }
.course-search-field { position: absolute; inset: 0; opacity: 0; visibility: hidden; clip-path: inset(-6px calc(100% - 34px) -6px -6px round 21px); transform: translateX(-4px); pointer-events: none; transition: clip-path 280ms cubic-bezier(.22, 1, .36, 1), transform 280ms cubic-bezier(.22, 1, .36, 1), opacity 160ms ease, visibility 0s linear 280ms; }
.course-search.is-open .course-search-field { opacity: 1; visibility: visible; clip-path: inset(-6px -6px -6px -6px round 21px); transform: translateX(0); pointer-events: auto; transition-delay: 0s; }
.course-search > button { transition: opacity 140ms ease; }
.course-search.is-open > button { opacity: 0; pointer-events: none; }
@media (prefers-reduced-motion: reduce) { .course-search-field, .course-search > button { transition: none; } }
.course-search-field .sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.course-search-field input { display: block; width: 100%; padding-right: 38px; }
.course-search-field input::-webkit-search-cancel-button { -webkit-appearance: none; }
.course-search-field > button { position: absolute; inset: 0 7px 0 auto; margin-block: auto; display: grid; place-items: center; width: 24px; height: 24px; padding: 0; border: 0; border-radius: 6px; background: transparent; color: var(--text-secondary); }
.course-search-field > button svg { display: block; width: 16px; height: 16px; }
.course-search-field > button:hover, .course-search-field > button:focus-visible { background: var(--bg-tertiary); color: var(--text-primary); }
input { width: 100%; height: 38px; padding: 0 12px; border: 1px solid var(--border); border-radius: 15px; background: var(--bg-secondary); color: var(--text-primary); font-size: .875rem; }
#courseLessons { flex: 1; min-height: 0; overflow-y: auto; padding: 0 8px; }
nav section { margin: 8px 0 20px; }
nav h3 { font-size: .75rem; color: var(--text-secondary); margin: 10px 12px 5px; }
nav button { display: block; text-align: left; width: 100%; margin: 2px 0; padding: 9px 12px; border: 0; background: transparent; font-size: .8125rem; overflow-wrap: anywhere; }
.course-sidebar-footer { margin-top: auto; padding: 10px 0; }
.course-sidebar-footer button { display: flex; align-items: center; gap: 12px; width: 100%; border: 0; background: transparent; color: var(--text-secondary); text-align: left; }
.course-sidebar-footer svg { width: 20px; height: 20px; }
main { display: flex; flex-direction: column; min-width: 0; min-height: 0; margin: 18px 10px 10px 6px; border: 0; background: var(--bg-primary); overflow: hidden; }
header { display: flex; align-items: center; gap: 14px; padding: 12px; min-height: 44px; }
header h2 { flex: 1; }
.course-badge { font-size: .75rem; font-weight: 600; padding: 3px 8px; border-radius: 7px; color: var(--text-secondary); background: var(--bg-tertiary); }
#courseHome { padding: 5px 10px; font-size: .75rem; }
#courseStatus { color: var(--text-secondary); font-size: .75rem; margin: 0 8px 12px; }
.course-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 16px; overflow: auto; padding: 4px 32px 32px; }
.course-card { text-align: left; min-height: 160px; padding: 22px; border-radius: var(--course-control-radius); }
.course-card strong { display: block; margin: 14px 0; font-size: 1rem; }
.course-card span { color: var(--text-secondary); font-size: .75rem; }
#coursePlayer { display: block; width: 100%; flex: 1; min-height: 0; margin: 0; border: 0; background: var(--bg-primary); }
dialog { width: min(420px, calc(100vw - 32px)); border: 1px solid var(--border); border-radius: var(--course-panel-radius); padding: 18px; background: var(--bg-secondary); color: var(--text-primary); box-shadow: 0 20px 70px #0003; }
dialog::backdrop { background: #18223655; backdrop-filter: blur(3px); }
dialog header { padding: 0; } dialog h2 { font-size: 1rem; }
dialog p { color: var(--text-secondary); line-height: 1.6; }
.course-setting { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 14px 0; }
select { padding: 8px; border: 1px solid var(--border); border-radius: var(--course-control-radius); background: var(--bg-primary); color: inherit; }
[hidden] { display: none !important; }
@media (max-width: 700px) { body { grid-template-columns: 1fr; height: auto; min-height: 100dvh; } .course-sidebar { height: 38dvh; min-height: 280px; } .course-brand { margin-bottom: 10px; } main { min-height: 62dvh; margin: 8px; } #coursePlayer { min-height: 55dvh; } .course-cards { padding: 12px; } }
/* Share the main app's compact rail and drag behaviour without its stores. */
body.app-shell { grid-template-columns: var(--sidebar-size) minmax(0, 1fr); height: 100dvh; }
.course-brand button { display: grid; place-items: center; padding: 4px; border: 0; background: transparent; flex: 0 0 auto; }
.course-sidebar { overflow: hidden; }
.course-navigation-empty { font-size: .8125rem; color: var(--text-secondary); line-height: 1.6; padding: 8px; }
nav .course-collection-toggle { display: flex; align-items: center; gap: 10px; font-size: .75rem; font-weight: 600; color: var(--text-secondary); }
.course-collection-count { margin-left: auto; }
.course-collection-lessons { padding-left: 20px; }
nav .course-collection-lessons > button { position: relative; padding-right: 28px; }
nav .course-collection-lessons > button[aria-current="true"]::after { content: ''; position: absolute; right: 14px; top: 50%; width: 8px; height: 8px; border-radius: 50%; background: var(--course-accent); transform: translateY(-50%); }
nav button[aria-current="true"] { background: var(--bg-tertiary); font-weight: 600; }
html.is-resizing, html.is-resizing * { cursor: col-resize !important; user-select: none; }
html.is-resizing iframe { pointer-events: none; }
@media (min-width: 701px) {
  .sidebar-compact .course-brand > span, .sidebar-compact .course-identity, .sidebar-compact #loadCourse, .sidebar-compact .course-search, .sidebar-compact #courseLessons, .sidebar-compact #courseStatus { display: none; }
  .sidebar-compact .course-brand { margin-inline: auto; }
  .sidebar-compact .course-sidebar-footer button { font-size: 0; justify-content: center; padding-inline: 0; gap: 0; }
}
@media (max-width: 700px) { body.app-shell { grid-template-columns: 1fr; height: auto; } #courseSidebarResizer, #courseSidebarToggle { pointer-events: none; } #courseSidebarResizer { display: none; } }


:root { --course-accent: #6b8cff; }
#courseSidebarResizer::after {
  content: ''; position: absolute; inset: 0 auto 0 50%; width: 1px;
  transform: translateX(-50%); pointer-events: none; box-shadow: none;
  background: linear-gradient(to bottom, transparent 0%, color-mix(in srgb, var(--border) 18%, transparent) 18%, color-mix(in srgb, var(--border) 68%, transparent) 38%, var(--border) 50%, color-mix(in srgb, var(--border) 68%, transparent) 62%, color-mix(in srgb, var(--border) 18%, transparent) 82%, transparent 100%);
}
#courseSidebarResizer:hover::after,
#courseSidebarResizer:focus-visible::after,
#courseSidebarResizer.is-resizing::after {
  background: linear-gradient(to bottom, transparent 0%, color-mix(in srgb, var(--course-accent) 18%, transparent) 18%, color-mix(in srgb, var(--course-accent) 68%, transparent) 38%, var(--course-accent) 50%, color-mix(in srgb, var(--course-accent) 68%, transparent) 62%, color-mix(in srgb, var(--course-accent) 18%, transparent) 82%, transparent 100%);
}
.course-setting-menu { position: relative; }
.course-setting-trigger { min-width: 112px; text-align: left; background: var(--bg-primary); }
.course-setting-trigger[aria-expanded="true"] { border-color: var(--course-accent); }
.course-setting-popup { position: absolute; bottom: calc(100% + 8px); right: 0; z-index: 2; min-width: 176px; padding: 6px; border: 1px solid var(--border); border-radius: var(--course-panel-radius); background: var(--surface-glass-strong); backdrop-filter: blur(18px); box-shadow: 0 8px 28px #0002; }
.course-setting-popup button { display: block; width: 100%; min-height: 40px; text-align: left; padding: 10px 12px; border: 0; background: transparent; }
.course-setting-popup button:hover, .course-setting-popup button[aria-pressed="true"] { background: var(--bg-hover); }
.course-setting-popup button[aria-pressed="true"] { font-weight: 600; }

.course-intro { flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; padding: 48px 24px; gap: 18px; }
.course-intro .hero-splash-mark { display: block; width: 58.4px; height: 66.4px; fill: currentColor; color: var(--course-accent); margin-bottom: 14px; }
.course-intro h2 { font-size: 1.5rem; font-weight: 600; letter-spacing: -.025em; }
.course-intro p { max-width: 340px; margin: 0; color: var(--text-secondary); font-size: .875rem; line-height: 1.7; }
.course-intro button { margin-top: 6px; padding: 11px 20px; }

.course-cover { flex: 1; display: grid; place-content: center; justify-items: center; gap: 22px; min-height: 0; padding: 48px 24px; text-align: center; }
.course-title-card { display: grid; align-content: center; width: min(620px, 100%); min-height: min(360px, 52vh); padding: clamp(42px, 8vw, 88px); border: 1px solid var(--border); border-radius: clamp(24px, 4vw, 40px); background: var(--canvas-surface); box-shadow: 0 18px 50px color-mix(in srgb, var(--text-primary) 8%, transparent); }
.course-title-card > span { color: var(--course-accent); font-size: .6875rem; font-weight: 700; letter-spacing: .14em; text-transform: uppercase; }
.course-title-card h2 { margin: 18px 0 20px; font-size: clamp(2rem, 5vw, 4.25rem); font-weight: 650; line-height: 1.05; letter-spacing: -.045em; overflow-wrap: anywhere; }
.course-title-card p, .course-cover-hint { margin: 0; color: var(--text-secondary); }
.course-title-card p { font-size: .8125rem; }
.course-cover-hint { font-size: .75rem; }

/* ===== Saved courses ===== */
/* A student's own shelf: links they added once, in the sidebar above the
 * lessons of whichever one is open. */
.course-saved { display: grid; gap: 2px; margin: 14px 0 4px; }
.course-saved header { display: flex; align-items: center; gap: 8px; padding: 0 8px 4px; }
.course-saved h2 { flex: 1; margin: 0; font-size: .6875rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--text-secondary); }
.course-saved header button { display: grid; place-items: center; width: 22px; height: 22px; padding: 0; border: 1px solid var(--border); border-radius: 6px; background: transparent; color: var(--text-secondary); font-size: .875rem; line-height: 1; }
.course-saved header button:hover { background: var(--bg-hover); color: var(--text-primary); }
.course-saved-empty { margin: 2px 8px 6px; font-size: .75rem; line-height: 1.6; color: var(--text-secondary); }
.course-saved-empty[hidden] { display: none; }
.course-saved-list { display: grid; gap: 1px; }
.course-saved-item { display: flex; align-items: center; gap: 4px; border-radius: var(--course-control-radius); }
.course-saved-item:hover { background: var(--bg-hover); }
.course-saved-item > button:first-child { flex: 1; min-width: 0; display: grid; gap: 1px; padding: 7px 8px; border: 0; background: transparent; text-align: left; }
.course-saved-item strong { display: block; overflow: hidden; font-size: .8125rem; font-weight: 500; white-space: nowrap; text-overflow: ellipsis; color: var(--text-primary); }
.course-saved-item small { display: block; overflow: hidden; font-size: .6875rem; white-space: nowrap; text-overflow: ellipsis; color: var(--text-secondary); }
.course-saved-item[aria-current="true"] { background: var(--bg-tertiary); }
.course-saved-item[aria-current="true"] strong { font-weight: 700; }
.course-saved-remove { flex: 0 0 auto; width: 24px; height: 24px; margin-right: 4px; padding: 0; border: 0; border-radius: 6px; background: transparent; color: var(--text-secondary); opacity: 0; }
.course-saved-item:hover .course-saved-remove, .course-saved-remove:focus-visible { opacity: 1; }
.course-saved-remove:hover { background: var(--bg-primary); color: var(--text-primary); }
/* What the network is doing, said quietly. A student who is reading should not
 * be interrupted to be told the course is being checked. */
.course-saved-note { margin: 6px 8px 0; font-size: .6875rem; line-height: 1.5; color: var(--text-secondary); }
.course-saved-note[hidden] { display: none; }
.course-saved-note button { margin-top: 4px; padding: 4px 9px; border: 1px solid var(--border); border-radius: 6px; background: var(--bg-primary); color: var(--text-primary); font-size: .6875rem; font-weight: 600; }

/* ===== Adding a course ===== */
.course-add-field { display: grid; gap: 5px; margin: 0 0 12px; font-size: .75rem; font-weight: 600; color: var(--text-secondary); }
.course-add-field span { font-weight: 400; text-transform: none; opacity: .8; }
.course-add-field input { width: 100%; padding: 9px 11px; border: 1px solid var(--border); border-radius: 8px; background: var(--bg-primary); color: var(--text-primary); font: inherit; font-weight: 400; }
.course-add-field input:focus-visible { outline: 2px solid var(--course-accent); outline-offset: -1px; }
.course-add-error { margin: 0 0 12px; font-size: .75rem; line-height: 1.55; color: #b3261e; }
.course-add-error[hidden] { display: none; }
html[data-theme="dark"] .course-add-error { color: #ffb4ab; }
.course-add-actions { display: flex; justify-content: flex-end; }
.course-add-actions button { padding: 9px 16px; font-weight: 600; }
.course-add-note { margin: 14px 0 0; font-size: .6875rem; line-height: 1.6; color: var(--text-secondary); }

/* Keep the course shelf distinct from the lessons beneath it. */
.course-saved { flex: 0 1 auto; min-height: 0; margin: 18px 4px 8px; padding: 12px 8px; border: 1px solid var(--border); border-radius: 14px; background: var(--bg-secondary); }
.course-saved header { padding: 0 4px 8px; }
.course-saved header button { width: auto; height: auto; min-height: 32px; padding: 6px 10px; font-size: .75rem; border-radius: 8px; color: var(--text-primary); }
.course-saved-list { max-height: 190px; overflow-y: auto; overscroll-behavior: contain; }
.course-saved-item { flex-shrink: 0; margin: 2px 0; }
.course-saved-item > button:first-child { min-height: 48px; gap: 4px; }
.course-saved-item[aria-current="true"] { box-shadow: inset 3px 0 var(--course-accent); }
.course-saved-remove { opacity: 1; width: auto; height: auto; min-height: 32px; padding: 5px 7px; font-size: .6875rem; }
#courseRefresh { justify-self: start; margin: 8px 4px 0; padding: 6px 8px; background: transparent; border: 0; font-size: .75rem; color: var(--text-secondary); }
#courseRefresh:hover { color: var(--text-primary); background: var(--bg-hover); }
.course-saved-note { font-size: .75rem; }
.course-intro-actions { display: grid; width: min(100%, 310px); grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.course-intro-actions button { width: 100%; }
#courseIntroLink, #courseIntroOpen { border-color: #17213b; background: #17213b; color: #f8faff; }
html[data-theme="dark"] #courseIntroLink, html[data-theme="dark"] #courseIntroOpen { border-color: #f8faff; background: #f8faff; color: #17213b; }
#courseAddSubmit { background: var(--text-primary); color: var(--bg-primary); }
button:disabled { cursor: wait; opacity: .6; }
#courseAddDialog { width: min(460px, calc(100vw - 32px)); }

@media (max-width: 700px) { .course-sidebar { overflow-y: auto; } .course-saved { flex-shrink: 0; } .course-saved-list { max-height: 120px; } .course-cover { padding: 24px 12px; } .course-title-card { width: 100%; min-height: 260px; padding: 36px 24px; } }

.course-collection { display: grid; grid-template-rows: auto minmax(0, 0fr); transition: grid-template-rows 240ms cubic-bezier(.22, 1, .36, 1); }
.course-collection.is-expanded { grid-template-rows: auto minmax(0, 1fr); }
.course-collection-body { min-height: 0; overflow: hidden; }
.course-collection-lessons { opacity: 0; visibility: hidden; transform: translateY(-4px); transition: opacity 130ms ease, transform 200ms cubic-bezier(.22, 1, .36, 1), visibility 0s linear 200ms; }
.course-collection.is-expanded .course-collection-lessons { opacity: 1; visibility: visible; transform: none; transition: opacity 150ms ease 45ms, transform 240ms cubic-bezier(.22, 1, .36, 1), visibility 0s; }
.course-collection-toggle[aria-expanded="true"] .sidebar-library-chevron { transform: rotate(45deg) translate(-1px, -1px); }
@media (prefers-reduced-motion: reduce) { .course-collection, .course-collection-lessons, .course-collection.is-expanded .course-collection-lessons, .course-collection-toggle .sidebar-library-chevron { transition: none; } }

/* Course management opens from the Course button without occupying lesson space. */
#courseChooser { position: fixed; inset: auto; margin: 0; width: min(380px, calc(100vw - 16px)); padding: 12px; overflow-y: auto; border: 1px solid var(--border); border-radius: 16px; background: var(--bg-primary); color: var(--text-primary); box-shadow: 0 12px 36px #0003; }
.course-chooser-heading { display: flex; align-items: center; justify-content: space-between; padding: 0 4px 10px; }
.course-chooser-heading > button { border: 0; background: transparent; padding: 4px 10px; font-size: 1.25rem; }
.course-chooser-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.course-chooser-actions > button { flex: 1; white-space: nowrap; font-size: .8125rem; }
#courseChooser .course-saved { border: 0; border-top: 1px solid var(--border); border-radius: 0; margin: 12px 0 0; padding: 12px 0 0; background: transparent; }
#courseChooser .course-saved-list { max-height: 260px; }
#loadCourse::after { content: ''; width: 6px; height: 6px; border-right: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; transform: rotate(45deg); margin: -3px 3px 0 2px; }

/* A reserved status slot keeps the course header and lesson list still. */
.course-sync-slot { display: grid; place-items: center; width: 26px; height: 28px; flex: 0 0 26px; margin-left: auto; }
.course-identity #courseSort { margin-left: 0; }
.course-sync { display: grid; place-items: center; width: 26px; height: 28px; }
.course-sync-label { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.course-sync-icon { display: block; font-size: 24px; font-weight: 700; line-height: 1; color: #23864b; }
[data-theme="dark"] .course-sync-icon { color: #66d994; }
.course-sync[data-state="success"] .course-sync-icon { animation: course-sync-appear 180ms ease-out; }
.course-sync[data-state="checking"] .course-sync-icon { width: 17px; height: 17px; border: 2px solid color-mix(in srgb, var(--course-accent) 22%, transparent); border-top-color: var(--course-accent); border-right-color: var(--course-accent); border-radius: 50%; animation: course-sync-spin 800ms linear infinite; }
.course-sync[data-state="warning"] .course-sync-icon { color: var(--text-secondary); font-size: 18px; }
.course-sync button { display: grid; place-items: center; width: 26px; height: 28px; padding: 0; border: 0; background: transparent; color: var(--course-accent); font-size: 22px; }
@keyframes course-sync-spin { to { transform: rotate(360deg); } }
@keyframes course-sync-appear { from { opacity: 0; transform: scale(.7); } to { opacity: 1; transform: scale(1); } }
@media (prefers-reduced-motion: reduce) { .course-sync .course-sync-icon { animation: none !important; } }

.course-lesson-row { position: relative; display: flex; align-items: center; border-radius: var(--course-control-radius); padding-right: 28px; margin: 2px 0; }
.course-lesson-row:hover { background: var(--bg-hover); }
.course-lesson-row.is-current { background: var(--bg-tertiary); }
.course-lesson-row.is-current::after { content: ''; position: absolute; right: 14px; top: 50%; width: 8px; height: 8px; border-radius: 50%; background: var(--course-accent); transform: translateY(-50%); }
nav .course-lesson-row > .course-lesson-open { flex: 1; min-width: 0; margin: 0; background: transparent; }
nav .course-lesson-response { width: 30px; height: 30px; flex: 0 0 30px; margin: 0 3px; padding: 0; text-align: center; font-size: 19px; color: var(--text-secondary); }
.course-lesson-response[data-response="none"] { opacity: 1; }
.course-lesson-row:hover .course-lesson-response, .course-lesson-response:focus-visible { opacity: 1; }
.course-lesson-response[data-response="read"] { color: #23864b; }
[data-theme="dark"] .course-lesson-response[data-response="read"] { color: #66d994; }
.course-lesson-response[data-response="revisit"] { color: var(--course-accent); }
#lessonResponsePopup { position: fixed; inset: auto; margin: 0; width: min(220px, calc(100vw - 16px)); max-height: calc(100dvh - 16px); overflow: auto; padding: 12px; border: 1px solid var(--border); border-radius: 16px; color: var(--text-primary); background: var(--bg-primary); box-shadow: 0 12px 36px #0003; }
#lessonResponsePopup strong { display: block; padding: 2px 6px; }
#lessonResponsePopup p { margin: 4px 6px 10px; color: var(--text-secondary); font-size: .6875rem; }
#lessonResponsePopup button { display: block; width: 100%; text-align: left; border: 0; background: transparent; margin: 2px 0; }
#lessonResponsePopup button:hover, #lessonResponsePopup button[aria-pressed="true"] { background: var(--bg-tertiary); }


nav .course-lesson-response { display: grid; place-items: center; }
#lessonResponsePopup button { display: flex; align-items: center; gap: 10px; }
.lesson-response-icon { display: block; width: 19px; height: 19px; flex: 0 0 19px; }
.lesson-response-icon[data-response="none"] { color: #a4aab5; }
.lesson-response-icon[data-response="read"] { color: #23864b; }
.lesson-response-icon[data-response="revisit"] { color: #d97706; }
.lesson-response-icon[data-response="help"] { color: #dc3b42; }
[data-theme="dark"] .lesson-response-icon[data-response="read"] { color: #66d994; }
[data-theme="dark"] .lesson-response-icon[data-response="revisit"] { color: #f5a342; }
[data-theme="dark"] .lesson-response-icon[data-response="help"] { color: #ff7078; }