:root {
  --ink: #10162d;
  --muted: #626c82;
  --line: #dfe4ee;
  --paper: #ffffff;
  --soft: #f5f7fb;
  --violet: #5d46e8;
  --violet-deep: #4330bd;
  --violet-soft: #eeecff;
  --navy: #071a3a;
  --navy-2: #0c2a57;
  --blue: #236fe0;
  --mint: #2c9d83;
  --mint-soft: #e8f7f2;
  --gold: #b77d19;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 18px;
  --shadow: 0 18px 42px rgba(7, 26, 58, .12);
  font-family: "Noto Sans SC", "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  color: var(--ink);
  background: var(--paper);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body { min-width: 320px; margin: 0; overflow-x: hidden; background: var(--paper); color: var(--ink); }
a, button, summary { -webkit-tap-highlight-color: transparent; }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 3px solid rgba(93, 70, 232, .3); outline-offset: 3px; }
button { font: inherit; }
svg { display: block; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.visually-hidden { position: absolute !important; width: 1px !important; height: 1px !important; padding: 0 !important; overflow: hidden !important; clip: rect(0, 0, 0, 0) !important; white-space: nowrap !important; border: 0 !important; }
.skip-link { position: fixed; z-index: 1000; top: 8px; left: 8px; padding: 10px 14px; border-radius: 8px; background: #fff; color: var(--ink); transform: translateY(-160%); }
.skip-link:focus { transform: none; }

.site-header { position: relative; z-index: 20; min-height: 76px; display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 28px; padding: 12px clamp(22px, 3.6vw, 58px); border-bottom: 1px solid var(--line); background: rgba(255, 255, 255, .98); }
.brand { color: var(--ink); text-decoration: none; font-size: clamp(1.38rem, 1.8vw, 1.86rem); font-weight: 850; letter-spacing: -.035em; }
.brand i { color: var(--violet); font-style: normal; }
nav { display: flex; justify-content: center; gap: 4px; }
nav a { padding: 9px 10px; border-radius: 9px; color: #454b5d; text-decoration: none; white-space: nowrap; font-size: .83rem; font-weight: 680; }
nav a:hover { background: #f2f0ff; }
nav a[aria-current="page"] { background: var(--violet-soft); color: var(--violet-deep); }
.account { min-width: 86px; min-height: 42px; padding: 0 14px; border: 1px solid #cfd4e0; border-radius: 11px; background: #fff; color: var(--ink); font-size: .82rem; font-weight: 750; cursor: pointer; }
.account .avatar { display: inline-grid; place-items: center; width: 24px; height: 24px; margin-right: 7px; overflow: hidden; border-radius: 8px; background: var(--violet); color: #fff; font-size: .7rem; }
.account .avatar img { width: 100%; height: 100%; object-fit: cover; }

main { width: min(1480px, calc(100% - 52px)); margin: 0 auto; padding: 20px 0 46px; }
.page-intro { min-height: 42px; display: flex; align-items: center; justify-content: space-between; gap: 22px; margin-bottom: 12px; }
.page-intro h1 { margin: 0; font-size: clamp(1.4rem, 2vw, 1.82rem); line-height: 1.1; letter-spacing: -.025em; }
.page-intro p { display: inline; margin: 0 0 0 12px; color: var(--muted); font-size: .86rem; }
.page-intro > div { display: flex; align-items: baseline; }
.page-intro > a, .panel-action { min-height: 44px; display: inline-flex; align-items: center; gap: 7px; color: var(--violet-deep); text-decoration: none; font-size: .82rem; font-weight: 780; }
.page-intro > a svg, .panel-action svg { width: 17px; height: 17px; }

.course-gallery { position: relative; }
.course-rail-wrap { position: relative; }
.content-rail { display: grid; grid-auto-flow: column; overflow-x: auto; overscroll-behavior-inline: contain; scroll-behavior: smooth; scroll-snap-type: x mandatory; scrollbar-width: none; }
.content-rail::-webkit-scrollbar { display: none; }
.course-rail { grid-auto-columns: clamp(340px, 31.8vw, 475px); gap: 14px; padding: 3px 1px 8px; scroll-padding-inline: 1px; }
.course-card { position: relative; min-height: 248px; display: block; overflow: hidden; border-radius: var(--radius-lg); background: var(--navy); color: #fff; text-decoration: none; scroll-snap-align: start; box-shadow: var(--shadow); isolation: isolate; }
.course-card::after { content: ""; position: absolute; z-index: 3; inset: 0; border: 1px solid rgba(255, 255, 255, .13); border-radius: inherit; pointer-events: none; }
.course-card img { position: absolute; z-index: 0; inset: 0; width: 100%; height: 100%; object-fit: cover; transition: transform .5s cubic-bezier(.16, 1, .3, 1); }
.course-card:hover img { transform: scale(1.025); }
.course-shade { position: absolute; z-index: 1; inset: 0; background: linear-gradient(90deg, rgba(3, 13, 34, .96) 0%, rgba(4, 15, 38, .84) 43%, rgba(4, 15, 38, .22) 76%, rgba(4, 15, 38, .08) 100%); }
.course-copy { position: absolute; z-index: 2; inset: 0; display: flex; flex-direction: column; justify-content: flex-end; width: 78%; padding: 22px 24px; }
.course-copy small { color: #9fb9ef; font-size: .77rem; font-weight: 760; }
.course-copy strong { margin-top: 9px; font-size: clamp(1.16rem, 1.45vw, 1.5rem); line-height: 1.25; letter-spacing: -.02em; text-wrap: balance; }
.course-copy em { margin-top: 7px; color: #d5dfef; font-size: .84rem; line-height: 1.45; font-style: normal; }
.course-progress { width: max-content; margin-top: 18px; padding-top: 9px; border-top: 1px solid rgba(255, 255, 255, .28); color: #fff; font-size: .78rem; font-weight: 750; }
.course-card.is-track-match { box-shadow: 0 0 0 3px #a99bff, var(--shadow); }
.course-nav { position: absolute; z-index: 5; top: 50%; width: 48px; height: 48px; display: grid; place-items: center; border: 1px solid rgba(7, 26, 58, .12); border-radius: 50%; background: #fff; color: var(--navy); cursor: pointer; box-shadow: 0 12px 28px rgba(7, 26, 58, .18); transform: translateY(-50%); }
.course-nav:hover { background: var(--navy); color: #fff; }
.course-nav svg { width: 19px; height: 19px; }
.course-nav--prev { left: -21px; }
.course-nav--next { right: -21px; }
.course-pagination { min-height: 25px; display: flex; align-items: center; justify-content: center; gap: 8px; padding-top: 5px; }
.course-pagination button { width: 44px; height: 44px; padding: 0; border: 0; background: transparent; cursor: pointer; }
.course-pagination button::before { content: ""; display: block; width: 7px; height: 7px; margin: auto; border-radius: 50%; background: #cbd1de; }
.course-pagination button[aria-current="true"]::before { width: 24px; border-radius: 5px; background: var(--violet); }

.track-context { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin: 8px 0 0; padding: 11px 15px; border-radius: 11px; background: var(--violet-soft); }
.track-context div { min-width: 0; display: flex; align-items: baseline; gap: 10px; }
.track-context strong { font-size: .84rem; }
.track-context p { margin: 0; overflow: hidden; color: #60687b; text-overflow: ellipsis; white-space: nowrap; font-size: .78rem; }
.track-context a { flex: 0 0 auto; color: var(--violet-deep); text-decoration: none; font-size: .78rem; font-weight: 780; }

.learning-status { margin-top: 12px; border: 1px solid var(--line); border-radius: var(--radius-md); background: #fff; box-shadow: 0 9px 28px rgba(7, 26, 58, .06); }
.learning-status > summary { min-height: 66px; display: grid; grid-template-columns: 38px minmax(170px, .62fr) minmax(290px, 1.2fr) minmax(170px, .72fr) auto; align-items: center; gap: 17px; padding: 8px 14px; list-style: none; cursor: pointer; }
.learning-status > summary::-webkit-details-marker { display: none; }
.status-eye { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 11px; background: var(--violet-soft); color: var(--violet-deep); }
.status-eye svg { width: 22px; height: 22px; }
.status-level, .status-current, .status-milestones { min-width: 0; }
.status-level b, .status-level small, .status-current small, .status-current b, .status-current em { display: block; }
.status-level b { font-size: .9rem; }
.status-level small, .status-current small, .status-current em { margin-top: 3px; color: var(--muted); font-size: .72rem; font-style: normal; }
.status-current { display: grid; grid-template-columns: minmax(0, 1fr) auto; column-gap: 14px; }
.status-current small { grid-column: 1 / -1; margin: 0 0 3px; }
.status-current b { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: .88rem; }
.status-current em { margin: 0; white-space: nowrap; }
.status-milestones b { display: block; font-size: .78rem; }
.progress-track { display: block; width: 100%; height: 6px; margin-top: 8px; overflow: hidden; border-radius: 4px; background: #e6e9f0; }
.progress-track i { display: block; width: 0; height: 100%; border-radius: inherit; background: var(--mint); }
.status-toggle { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 0 15px; border-radius: 10px; background: var(--navy); color: #fff; font-size: .78rem; font-weight: 780; white-space: nowrap; }
.status-toggle svg { width: 17px; height: 17px; transition: transform .2s ease; }
.learning-status[open] .status-toggle svg { transform: rotate(180deg); }
.status-detail { padding: 0 16px 16px; border-top: 1px solid var(--line); }
.status-detail-heading { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 15px 2px 11px; }
.status-detail-heading h2 { margin: 0; font-size: 1.08rem; }
.status-detail-heading p { margin: 4px 0 0; color: var(--muted); font-size: .76rem; }
.status-detail-actions { display: flex; align-items: center; gap: 8px; }
.login-growth { min-height: 44px; padding: 0 14px; border: 1px solid #cbc3f7; border-radius: 10px; background: #fff; color: var(--violet-deep); font-size: .78rem; font-weight: 750; cursor: pointer; }
.status-next-link { min-height: 44px; display: inline-flex; align-items: center; gap: 7px; padding: 0 14px; border-radius: 10px; background: var(--violet); color: #fff; text-decoration: none; white-space: nowrap; font-size: .78rem; font-weight: 780; }
.status-next-link svg { width: 16px; height: 16px; }
.direction-rail { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 9px; margin: 0; padding: 0; list-style: none; }
.direction-card button { width: 100%; min-height: 86px; display: grid; grid-template-columns: auto minmax(0, 1fr) auto; align-items: center; gap: 5px 10px; padding: 12px; border: 1px solid var(--line); border-radius: 12px; background: #fff; color: var(--ink); text-align: left; cursor: pointer; }
.direction-card button:hover, .direction-card button[aria-selected="true"] { border-color: #8d7af2; background: #f8f7ff; }
.direction-number { width: 36px; height: 36px; display: grid; place-items: center; border-radius: 10px; background: var(--violet-soft); color: var(--violet-deep); font-size: .68rem; font-weight: 900; }
.direction-copy { min-width: 0; }
.direction-copy strong, .direction-copy small { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.direction-copy strong { font-size: .82rem; }
.direction-copy small { margin-top: 3px; color: var(--muted); font-size: .69rem; }
.direction-state { color: var(--muted); font-size: .68rem; font-weight: 750; }
.direction-progress { grid-column: 1 / -1; height: 4px; overflow: hidden; border-radius: 4px; background: #e6e9f0; }
.direction-progress i { display: block; height: 100%; background: var(--violet); }
.direction-card em { display: none; }
.direction-card.is-completed .direction-number { background: var(--mint-soft); color: #147560; }
.direction-card.is-completed .direction-progress i { background: var(--mint); }
.direction-card.is-locked { opacity: .7; }
.stage-focus { min-height: 78px; display: flex; align-items: center; justify-content: space-between; gap: 20px; margin-top: 9px; padding: 13px 15px; border-radius: 12px; background: var(--navy); color: #fff; }
.stage-focus span { color: #92b4ec; font-size: .7rem; font-weight: 760; }
.stage-focus h3 { margin: 4px 0 3px; font-size: .95rem; }
.stage-focus p { max-width: 78ch; margin: 0; color: #bac6d9; font-size: .76rem; line-height: 1.5; }
.stage-focus__action { flex: 0 0 auto; display: flex; align-items: center; gap: 13px; }
.stage-focus__action strong { color: #c6d0df; font-size: .72rem; white-space: nowrap; }
.stage-focus__action a { min-height: 44px; display: inline-flex; align-items: center; gap: 7px; padding: 0 15px; border-radius: 10px; background: var(--violet); color: #fff; text-decoration: none; font-size: .78rem; font-weight: 800; }
.stage-focus__action svg { width: 16px; height: 16px; }

.learning-library { margin-top: 14px; border: 1px solid var(--line); border-radius: var(--radius-lg); background: #fff; box-shadow: 0 12px 34px rgba(7, 26, 58, .06); }
.library-tabs { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); padding: 0 18px; border-bottom: 1px solid var(--line); }
.library-tabs button { position: relative; min-height: 54px; border: 0; background: transparent; color: #555f74; font-size: .86rem; font-weight: 760; cursor: pointer; }
.library-tabs button::after { content: ""; position: absolute; right: 12%; bottom: -1px; left: 12%; height: 3px; border-radius: 3px 3px 0 0; background: transparent; }
.library-tabs button[aria-selected="true"] { color: var(--violet-deep); }
.library-tabs button[aria-selected="true"]::after { background: var(--violet); }
.library-panel { min-height: 212px; padding: 18px; }
.topic-rail { display: grid; grid-template-columns: repeat(6, minmax(190px, 1fr)); gap: 12px; overflow-x: auto; padding: 2px 2px 10px; scroll-snap-type: x proximity; scrollbar-color: rgba(110, 64, 255, .3) transparent; scrollbar-width: thin; }
.video-rail, .project-rail { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; }
.topic-card, .video-card, .project-card, .learning-entrances a { min-width: 0; overflow: hidden; border-radius: 13px; background: #fff; color: var(--ink); text-decoration: none; box-shadow: 0 8px 22px rgba(10, 28, 63, .09); transition: transform .24s cubic-bezier(.16, 1, .3, 1), box-shadow .24s cubic-bezier(.16, 1, .3, 1); }
.topic-card:hover, .video-card:hover, .project-card:hover, .learning-entrances a:hover { transform: translateY(-4px); box-shadow: 0 16px 34px rgba(10, 28, 63, .16); }
.topic-card:focus-visible, .video-card:focus-visible, .project-card:focus-visible, .learning-entrances a:focus-visible { outline: 3px solid rgba(110, 64, 255, .34); outline-offset: 3px; }
.topic-card { scroll-snap-align: start; }
.library-card-cover { position: relative; display: block; overflow: hidden; aspect-ratio: 16 / 9; background: var(--navy); }
.library-card-cover::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 64%, rgba(4, 13, 35, .2)); pointer-events: none; }
.library-card-cover img { width: 100%; height: 100%; display: block; object-fit: cover; transition: transform .5s cubic-bezier(.16, 1, .3, 1), filter .3s ease; }
.topic-card:hover .library-card-cover img, .project-card:hover .library-card-cover img, .learning-entrances a:hover .library-card-cover img { transform: scale(1.035); filter: saturate(1.08); }
.library-card-copy { display: block; padding: 12px 13px 13px; }
.library-card-copy strong, .library-card-copy small, .library-card-copy em { display: block; }
.library-card-copy strong { font-size: .9rem; line-height: 1.35; }
.library-card-copy small { min-height: 2.9em; margin-top: 5px; color: #667086; font-size: .8rem; line-height: 1.45; }
.library-card-copy small b { color: var(--violet-deep); font-weight: 820; }
.library-card-copy em { margin-top: 9px; color: var(--violet-deep); font-size: .8rem; font-style: normal; font-weight: 800; line-height: 1.35; }
.video-cover { position: relative; display: block; overflow: hidden; aspect-ratio: 16 / 9; background: var(--navy); }
.video-cover::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 55%, rgba(4, 13, 35, .28)); pointer-events: none; }
.video-cover img { width: 100%; height: 100%; display: block; object-fit: cover; transition: transform .5s cubic-bezier(.16, 1, .3, 1), filter .3s ease; }
.video-card:hover .video-cover img { transform: scale(1.035); filter: saturate(1.08); }
.video-play { position: absolute; z-index: 2; top: 50%; left: 50%; width: 48px; height: 48px; display: grid; place-items: center; border-radius: 50%; background: rgba(255, 255, 255, .96); color: var(--violet-deep); box-shadow: 0 10px 28px rgba(4, 13, 35, .28); transform: translate(-50%, -50%); transition: transform .22s cubic-bezier(.16, 1, .3, 1), background-color .22s ease; }
.video-card:hover .video-play { background: #fff; transform: translate(-50%, -50%) scale(1.09); }
.video-play svg { width: 25px; height: 25px; margin-left: 2px; }
.video-copy { display: block; padding: 12px 13px 13px; }
.video-copy strong, .video-copy em, .video-copy small { display: block; }
.video-copy strong { font-size: .92rem; line-height: 1.35; }
.video-copy em { min-height: 2.9em; margin-top: 5px; color: #667086; font-size: .78rem; font-style: normal; line-height: 1.45; }
.video-copy small { margin-top: 9px; color: #788197; font-size: .75rem; line-height: 1.35; }
.video-copy small b { color: var(--violet-deep); font-weight: 800; }
.panel-action { width: max-content; margin: 10px 0 -8px auto; }
.learning-entrances { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 13px; }
.learning-entrances a { display: grid; grid-template-columns: minmax(0, .92fr) minmax(0, 1.08fr); align-items: stretch; }
.learning-entrances .library-card-cover { aspect-ratio: auto; min-height: 172px; }
.learning-entrances .library-card-copy { align-self: center; padding: 20px; }
.learning-entrances .library-card-copy strong { font-size: 1rem; }
.learning-entrances .library-card-copy small { min-height: auto; font-size: .79rem; }

.level-toast { position: fixed; z-index: 90; right: 24px; bottom: 24px; width: min(340px, calc(100% - 32px)); padding: 20px 22px; border-radius: var(--radius-md); background: var(--navy); color: #fff; box-shadow: 0 20px 60px rgba(16, 21, 59, .28); }
.level-toast > span { color: #e6bd65; font-size: .74rem; font-weight: 900; }
.level-toast strong { display: block; margin-top: 6px; font-size: 1.06rem; }
.level-toast p { margin: 5px 0 0; color: #bbc5da; font-size: .82rem; }
footer { padding: 0 24px 24px; text-align: center; font-size: .76rem; }
footer a { color: #7e8596; text-decoration: none; }

@media (max-width: 1100px) {
  .site-header { grid-template-columns: 1fr auto; grid-template-rows: auto auto; }
  nav { grid-column: 1 / -1; justify-content: flex-start; overflow-x: auto; margin: 0 -22px; padding: 0 22px 4px; scrollbar-width: none; }
  nav::-webkit-scrollbar { display: none; }
  .course-rail { grid-auto-columns: min(58vw, 455px); }
  .learning-status > summary { grid-template-columns: 38px minmax(160px, .7fr) minmax(230px, 1fr) auto; }
  .status-milestones { display: none; }
  .video-rail, .project-rail { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 861px) and (max-width: 1199px) {
  .site-header { grid-template-columns: 1fr auto auto; }
  .site-header > nav[aria-label="AI历史书生态导航"] { display: none !important; }
  .site-header > .ecosystem-menu-button { display: inline-flex; margin-left: auto; }
}

@media (max-width: 720px) {
  main { width: 100%; padding: 14px 14px 34px; }
  .site-header { min-height: 60px; grid-template-columns: 1fr auto; grid-template-rows: auto; gap: 10px; padding: 10px 14px; }
  .site-header > nav[aria-label="AI历史书生态导航"] { display: none !important; }
  .site-header > .ecosystem-menu-button { display: inline-flex; margin-left: auto; }
  .brand { font-size: 1.34rem; }
  .account { max-width: 104px; min-width: 68px; min-height: 38px; padding: 0 10px; }
  .page-intro { min-height: 38px; margin-bottom: 9px; }
  .page-intro h1 { font-size: 1.36rem; }
  .page-intro p { display: none; }
  .page-intro > a { min-height: 44px; font-size: .75rem; }
  .course-rail-wrap { margin-inline: -14px; }
  .course-rail { grid-auto-columns: 86vw; gap: 10px; padding: 2px 14px 7px; scroll-padding-inline: 14px; }
  .course-card { min-height: 218px; }
  .course-copy { width: 88%; padding: 18px; }
  .course-copy small { font-size: .7rem; }
  .course-copy strong { font-size: 1.16rem; }
  .course-copy em { font-size: .76rem; }
  .course-progress { margin-top: 13px; font-size: .72rem; }
  .course-nav { top: auto; bottom: -37px; width: 44px; height: 44px; transform: none; box-shadow: 0 7px 18px rgba(7, 26, 58, .12); }
  .course-nav--prev { left: 14px; }
  .course-nav--next { right: 14px; }
  .course-pagination { min-height: 47px; padding-top: 7px; }

  .track-context { margin-top: 6px; }
  .track-context div { display: block; }
  .track-context p { margin-top: 4px; white-space: normal; }
  .track-context a { display: none; }
  .learning-status { margin-top: 9px; }
  .learning-status > summary { min-height: 68px; grid-template-columns: 36px minmax(0, 1fr) auto; gap: 9px; padding: 8px 10px; }
  .status-eye { width: 36px; height: 36px; }
  .status-level { display: none; }
  .status-current { display: block; }
  .status-current small { margin: 0 0 2px; }
  .status-current b { font-size: .8rem; }
  .status-current em { font-size: .67rem; }
  .status-toggle { min-width: 92px; min-height: 44px; padding: 0 10px; font-size: .7rem; }
  .status-detail { padding: 0 10px 10px; }
  .status-detail-heading { padding: 12px 1px 9px; }
  .status-detail-heading h2 { font-size: .96rem; }
  .status-detail-heading p { display: none; }
  .direction-rail { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .direction-card button { min-height: 80px; }
  .direction-state { display: none; }
  .stage-focus { display: block; }
  .stage-focus p { display: -webkit-box; overflow: hidden; -webkit-box-orient: vertical; -webkit-line-clamp: 2; }
  .stage-focus__action { justify-content: space-between; margin-top: 11px; }

  .learning-library { margin-top: 10px; border-radius: var(--radius-md); }
  .library-tabs { grid-template-columns: repeat(2, minmax(0, 1fr)); padding: 0 8px; }
  .library-tabs button { min-height: 46px; font-size: .78rem; }
  .library-panel { min-height: 238px; padding: 10px; }
  .topic-rail, .video-rail, .project-rail, .learning-entrances { display: grid; grid-auto-flow: column; grid-auto-columns: min(82vw, 330px); grid-template-columns: none; gap: 10px; overflow-x: auto; margin-inline: -10px; padding: 2px 10px 10px; scroll-padding-inline: 10px; scroll-snap-type: x mandatory; scrollbar-color: rgba(110, 64, 255, .32) transparent; scrollbar-width: thin; }
  .topic-card, .video-card, .project-card, .learning-entrances a { scroll-snap-align: start; }
  .library-card-copy { padding: 11px 12px 13px; }
  .library-card-copy strong { font-size: .9rem; }
  .library-card-copy small { min-height: auto; font-size: .8rem; }
  .library-card-copy em { font-size: .8rem; }
  .video-copy { padding: 11px 12px 13px; }
  .video-copy strong { font-size: .9rem; }
  .video-copy em { min-height: auto; font-size: .76rem; }
  .video-copy small { font-size: .72rem; }
  .panel-action { margin-top: 7px; }
  .learning-entrances a { display: block; }
  .learning-entrances .library-card-cover { min-height: 0; aspect-ratio: 16 / 9; }
  .learning-entrances .library-card-copy { padding: 13px; }
  .level-toast { right: 16px; bottom: 16px; }
}

@media (max-width: 390px) {
  .course-rail { grid-auto-columns: 88vw; }
  .course-card { min-height: 205px; }
  .course-copy strong { font-size: 1.05rem; }
  .page-intro > a { font-size: .7rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; scroll-behavior: auto !important; }
}