/* GENERATED from packages/design/header.css by packages/design/scripts/sync.mjs — do not edit here. */
/* Kardio platform header — ONE implementation for all three apps (HEADER.md).
   Requires tokens.css. Loaded by EKG Studio, EchoSchema AND the course
   (Tailwind): everything here is class-scoped, so unlike base.css it cannot
   restyle the course's own buttons. Do not add element selectors except on
   <html>.

   Every box in the header has a fixed size, so the header is pixel-identical
   across the apps and does not move while a page loads (late JS, account
   request, font swap) or when navigating Kurs ⇄ EKG ⇄ Echo:

     desktop (> 900px)   one row, height --header-h
       .brand (fixed width) · .platform-nav · [.header-app] · .header-actions
     ≤ 900px             row 1  .brand ……………………… .header-actions
                         row 2  .platform-nav
                         row 3  .header-app (fixed height, optional)

   The header rules are written to win over the element defaults of base.css
   (button padding/background) and over Tailwind's preflight alike. */

/* Same content width whether the page scrolls (course) or not (EKG/Echo
   lock the body to the viewport): with classic scrollbars the header would
   otherwise be ~15px wider in the two simulators than in the course. */
html { scrollbar-gutter: stable; }

.app-header {
  box-sizing: border-box;
  flex: 0 0 auto;
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: var(--header-gap);
  height: calc(var(--header-h) + env(safe-area-inset-top, 0px));
  margin: 0;
  padding: env(safe-area-inset-top, 0px) calc(var(--header-pad-x) + env(safe-area-inset-right, 0px)) 0 calc(var(--header-pad-x) + env(safe-area-inset-left, 0px));
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: var(--leading-ui);
  letter-spacing: normal;
  -webkit-font-smoothing: antialiased;
}
.app-header *, .app-header *::before, .app-header *::after { box-sizing: border-box; }

/* ── Brand: mark + app name, platform name below. Fixed width, so the
   platform switch starts at the same x in every app. ── */
.app-header .brand {
  display: flex;
  align-items: center;
  gap: 11px;
  flex: 0 0 auto;
  width: var(--header-brand-w);
  min-width: 0;
  height: var(--header-control-h-lg);
  color: var(--ink);
  text-decoration: none;
  font-size: var(--header-brand-size);
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -0.6px;
  white-space: nowrap;
}
.app-header .brand > span:last-child { display: block; min-width: 0; }
.app-header .brand strong { font-weight: 450; }
.app-header .brand small {
  display: block;
  margin-top: 2px;
  font-size: var(--text-2xs);
  font-weight: 500;
  line-height: 1.3;
  letter-spacing: 0.25px;
  color: var(--muted);
}
.app-header .brand-mark {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: var(--header-mark);
  height: var(--header-mark);
  border-radius: var(--radius-panel);
  background: var(--accent);
}
.app-header .brand-mark svg {
  display: block;
  width: calc(var(--header-mark) * 0.75);
  height: auto;
  fill: none;
  stroke: var(--on-accent);
  stroke-width: 1.7;
  stroke-linejoin: round;
  stroke-linecap: round;
}

/* ── Platform switch: Kurs · EKG · Echo · EP · Studien. Plain links; the current
   app carries aria-current="page". ── */
.app-header .platform-nav {
  display: flex;
  align-items: center;
  gap: 2px;
  flex: 0 0 auto;
  margin: 0;
}
.app-header .platform-nav a {
  display: inline-flex;
  align-items: center;
  height: var(--header-nav-h);
  padding: 0 10px;
  border-radius: var(--radius-input);
  color: var(--muted);
  font-size: var(--text-sm);
  font-weight: 500;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
}
.app-header .platform-nav a:hover { color: var(--ink); background: var(--surface-soft); }
.app-header .platform-nav a[aria-current="page"] { color: var(--accent-ink); background: var(--accent-soft); }

/* ── App slot: the app's own navigation (EKG mode tabs, Echo view select,
   course library). Takes the free space, never wraps the row. ── */
.app-header .header-app {
  display: flex;
  align-items: center;
  gap: 14px;
  flex: 1 1 auto;
  min-width: 0;
  height: var(--header-control-h-lg);
}

.app-header .mode-tabs {
  display: flex;
  gap: var(--space-1);
  margin: 0;
  padding: var(--space-1);
  background: var(--surface-soft);
  border-radius: var(--radius-panel);
  min-width: 0;
  overflow-x: auto;
  scrollbar-width: none;
}
.app-header .mode-tabs::-webkit-scrollbar { display: none; }
.app-header .mode-tab {
  flex: 0 0 auto;
  height: calc(var(--header-control-h-lg) - 2 * var(--space-1));
  min-height: 0;
  margin: 0;
  padding: 0 16px;
  border: 0;
  border-radius: var(--radius-button);
  background: transparent;
  color: var(--muted);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1;
  white-space: nowrap;
  box-shadow: none;
}
.app-header .mode-tab:hover { background: var(--surface); color: var(--ink); }
.app-header .mode-tab.active { background: var(--surface); color: var(--accent-ink); box-shadow: var(--shadow-raised); }

/* Text link inside the app slot (course: "Bibliothek"). */
.app-header .header-link {
  display: inline-flex;
  align-items: center;
  height: var(--header-control-h);
  padding: 0 11px;
  border-radius: var(--radius-button);
  color: var(--ink);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
}
.app-header .header-link:hover { background: var(--surface-soft); }
.app-header .header-link[aria-current="page"] { color: var(--accent-ink); background: var(--accent-soft); }

/* Select / checkbox row inside the app slot (Echo: view + compare). */
.app-header .header-select {
  height: var(--header-control-h);
  min-height: 0;
  min-width: 0;
  margin: 0;
  padding: 0 30px 0 11px;
  border: 1px solid var(--line);
  border-radius: var(--radius-input);
  background-color: var(--surface);
  color: var(--ink);
  font-size: var(--text-sm);
  line-height: 1;
}
.app-header .header-check {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0;
  color: var(--muted);
  font-size: var(--text-small);
  line-height: 1.5;
  white-space: nowrap;
  cursor: pointer;
  user-select: none;
}

/* ── Actions, right-aligned, always in this order:
     [app extras: badge, Hilfe] · [Sprache] · Theme ◐ · Konto ── */
.app-header .header-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 4px;
  flex: 0 0 auto;
  margin-left: auto;
  height: var(--header-control-h);
}
.app-header .header-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  flex: 0 0 auto;
  height: var(--header-control-h);
  min-height: 0;
  min-width: var(--header-control-h);
  margin: 0;
  padding: 0 11px;
  border: 1px solid transparent;
  border-radius: var(--radius-button);
  background: transparent;
  color: var(--ink);
  font-family: inherit;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  box-shadow: none;
}
.app-header .header-btn:hover { background: var(--surface-soft); border-color: var(--line); }
.app-header .header-btn[aria-expanded="true"] { background: var(--accent-soft); border-color: var(--accent); color: var(--accent-ink); }
.app-header select.header-btn { padding-right: 26px; border-color: var(--line); background-color: var(--surface); }
.app-header .header-btn.theme-btn { padding: 0; width: var(--header-control-h); font-size: 17px; font-weight: 400; }
/* Account: name or "Anmelden" in a FIXED-width slot (long names ellipsize,
   full name in the title), the same width as the placeholder shown while the
   session request is in flight — so neither the request nor the name moves
   the theme button, and it sits at the same x in every app. */
.app-header .header-btn.account-btn { width: var(--header-account-w); min-width: 0; padding: 0 8px; overflow: hidden; text-overflow: ellipsis; display: inline-block; line-height: calc(var(--header-control-h) - 2px); text-align: center; }
.app-header .header-btn.account-btn.signin { color: var(--accent-ink); }
.app-header .account-placeholder { display: inline-block; flex: 0 0 auto; width: var(--header-account-w); height: var(--header-control-h); }

.app-header .local-badge { display: inline-flex; align-items: center; margin-right: 8px; color: var(--muted); font-size: var(--text-xs); line-height: 1; white-space: nowrap; }
.app-header .local-badge i { display: inline-block; width: 6px; height: 6px; border-radius: 50%; background: var(--accent); margin-right: 5px; }

/* ── Disclaimer bar under the simulators' header. ── */
.disclaimer {
  box-sizing: border-box;
  flex: 0 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-3);
  height: var(--disclaimer-h);
  margin: 0;
  padding: 0 calc(var(--header-pad-x) + env(safe-area-inset-right, 0px)) 0 calc(var(--header-pad-x) + env(safe-area-inset-left, 0px));
  background: var(--bg);
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-family: var(--font-sans);
  font-size: var(--text-2xs);
  line-height: 1.3;
  white-space: nowrap;
  overflow: hidden;
}
.eyebrow { color: var(--accent); font-size: var(--text-xs); font-weight: 700; letter-spacing: 1.2px; }
.disclaimer .eyebrow { font-size: var(--text-2xs); }

.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;
}

@media (max-width: 1200px) {
  .app-header .local-badge { display: none; }
  .app-header .mode-tab { padding: 0 12px; }
}
/* iPad landscape (1024 px): EKG Studio's five tabs must still fit. */
@media (min-width: 901px) and (max-width: 1100px) {
  .app-header .mode-tab { padding: 0 8px; font-size: var(--text-small); }
}

/* ── Legacy stacked header (≤ 900 px): only for pages WITHOUT
   <html class="kardio-shell">. The apps that adopted the mobile shell (end of
   this file) never match these rules. Removed once every app has adopted the
   shell (HEADER.md "Mobile Shell", M0 PR 6). ── */
/* Stacked: brand + actions, then the platform switch, then the app slot. */
@media (max-width: 900px) {
  :root:not(.kardio-shell) .app-header {
    flex-wrap: wrap;
    align-content: flex-start;
    row-gap: var(--header-row-gap);
    column-gap: var(--space-3);
    height: auto;
    padding-top: calc(var(--header-pad-y-sm) + env(safe-area-inset-top, 0px));
    padding-bottom: var(--header-pad-y-sm);
    padding-left: calc(var(--header-pad-x-sm) + env(safe-area-inset-left, 0px));
    padding-right: calc(var(--header-pad-x-sm) + env(safe-area-inset-right, 0px));
  }
  /* Brand takes the space the actions leave (basis 0), so a long app name
     or account name truncates instead of wrapping the actions to a new row. */
  :root:not(.kardio-shell) .app-header .brand { order: 1; flex: 1 1 0; width: auto; height: var(--header-control-h); }
  :root:not(.kardio-shell) .app-header .brand > span:last-child { overflow: hidden; text-overflow: ellipsis; }
  :root:not(.kardio-shell) .app-header .header-actions { order: 2; }
  :root:not(.kardio-shell) .app-header .platform-nav { order: 3; width: 100%; }
  :root:not(.kardio-shell) .app-header .header-app { order: 4; width: 100%; flex: 0 0 100%; height: var(--header-slot-h); }
  :root:not(.kardio-shell) .app-header .mode-tabs { flex: 1 1 auto; }
  :root:not(.kardio-shell) .app-header .mode-tab { flex: 1 0 auto; padding: 0 10px; height: calc(var(--header-slot-h) - 2 * var(--space-1)); }
  :root:not(.kardio-shell) .app-header .header-select { flex: 1 1 auto; height: var(--header-slot-h); }
  :root:not(.kardio-shell) .disclaimer { padding-left: calc(var(--header-pad-x-sm) + env(safe-area-inset-left, 0px)); padding-right: calc(var(--header-pad-x-sm) + env(safe-area-inset-right, 0px)); }
  :root:not(.kardio-shell) .disclaimer .eyebrow { display: none; }
}
@media (max-width: 767px) {
  :root:not(.kardio-shell) .app-header .header-actions { gap: 2px; }
  :root:not(.kardio-shell) .app-header .header-btn { padding: 0 8px; }
  /* The prefix raises the rule above; restore the two base rules it used to lose to. */
  :root:not(.kardio-shell) .app-header .header-btn.theme-btn { padding: 0; }
  :root:not(.kardio-shell) .app-header select.header-btn { padding-right: 26px; }
  :root:not(.kardio-shell) .app-header .brand { font-size: 18px; }
  :root:not(.kardio-shell) .app-header .brand-mark { width: 34px; height: 34px; border-radius: 10px; }
  :root:not(.kardio-shell) .app-header .brand-mark svg { width: 24px; }
}
/* Phones: keep EKG Studio's five mode tabs on the one slot row. */
@media (max-width: 600px) {
  :root:not(.kardio-shell) .app-header .mode-tabs { gap: 2px; }
  :root:not(.kardio-shell) .app-header .mode-tab { padding: 0 5px; font-size: var(--text-small); }
}

/* Touch: the header controls already meet the target size via the row
   heights; keep them fixed instead of base.css's min-height: 44px so the
   header does not grow on tablets. */
@media (hover: none) and (pointer: coarse) {
  :root:not(.kardio-shell) .app-header .header-select { font-size: 16px; }
}

/* ── Mobile shell (opt-in: <html class="kardio-shell">; HEADER.md "Mobile Shell") ──
   Breakpoints (shell.js kardioShell.MQ):
     compact  (max-width: 900px), (max-width: 960px) and (max-height: 500px)
              one 52 px row (+ top inset), sticky, hides while scrolling down
     menu     (max-width: 600px), (max-width: 960px) and (max-height: 500px)
              actions collapse into ⋯ (.header-more), disclaimer → .stage-note
     mark     (max-width: 767px), (max-width: 960px) and (max-height: 500px)
              brand shows only the mark
     short    (max-width: 960px) and (max-height: 500px)
              landscape phones: platform links inline (no tab bar, tabbar.css);
              at high browser zoom (320 × 256 = 1280 × 1024 at 400 %) the
              links and the app slot scroll sideways instead of widening the page
     coarse   (hover: none) and (pointer: coarse): 44 × 44 px hit areas
              (transparent ::after, boxes unchanged); in the compact tier also
              44 px selects (a <select> cannot carry a hit area)
   Desktop (min-width: 961px), (min-width: 901px) and (min-height: 501px) renders
   exactly as without the class — with a mouse and on touch tablets. */
.kardio-shell .app-header .header-more,
.kardio-shell .app-header .header-only-compact { display: none; }
.kardio-shell .app-header .header-label { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
/* External links stay identifiable in every visible navigation layout. */
.kardio-shell .app-header .platform-nav .nav-ext { display: inline; margin-left: 3px; font-size: 12px; }
/* Account: the ellipsis moves to the inner span, so the button may carry a hit area. Desktop renders identically. */
.kardio-shell .app-header .header-btn.account-btn { overflow: visible; }
.kardio-shell .app-header .account-name { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
/* SHELL-09: overflow cue, only while shell.js reports overflow */
.kardio-shell .app-header .mode-tabs[data-overflow="end"]   { mask-image: linear-gradient(to right, #000 calc(100% - 24px), transparent); }
.kardio-shell .app-header .mode-tabs[data-overflow="start"] { mask-image: linear-gradient(to left, #000 calc(100% - 24px), transparent); }
.kardio-shell .app-header .mode-tabs[data-overflow="both"]  { mask-image: linear-gradient(to right, transparent, #000 24px, #000 calc(100% - 24px), transparent); }
/* A focused item scrolls clear of the 24 px fade (shell.js scrolls it into view). No layout effect. */
.kardio-shell .app-header .mode-tabs,
.kardio-shell [data-kardio-overflow] { scroll-padding-inline: 24px; }
/* Stacking: a sticky header is its own stacking context; raise it while one of its popovers is open (⋯ panel, Echo language menu) */
.kardio-shell .app-header:has([aria-expanded="true"]) { z-index: var(--z-menu); }
/* Disclaimer replacement where the bar is hidden (menu tier): one muted line at the end of each view. */
.kardio-shell .stage-note { display: none; }

@media (max-width: 900px), (max-width: 960px) and (max-height: 500px) {
  .kardio-shell {
    --header-total: calc(var(--header-h-sm) + env(safe-area-inset-top, 0px));
    scroll-padding-top: calc(var(--header-total) + var(--space-3));
    scroll-padding-bottom: calc(var(--tabbar-offset) + var(--space-3));
  }
  /* The sticky header lies inside that scroll-padding band, so Chromium took every focused header
     control (Tab into the header, focus back on ⋯ after Esc or a dialog) for off screen and
     scrolled the page by half a screen to reveal a control that never moves. Header controls are
     exempt from the band: the negative margin cancels it. */
  .kardio-shell .app-header a,
  .kardio-shell .app-header button,
  .kardio-shell .app-header select,
  .kardio-shell .app-header input { scroll-margin-top: calc(-1 * (var(--header-total) + var(--space-3))); }
  .kardio-shell .app-header {
    position: sticky; top: 0; z-index: var(--z-header);
    height: var(--header-total); gap: var(--space-2);
    padding: env(safe-area-inset-top, 0px) calc(var(--header-pad-x-sm) + env(safe-area-inset-right, 0px)) 0 calc(var(--header-pad-x-sm) + env(safe-area-inset-left, 0px));
    transition: transform .2s ease;
  }
  /* Reveal (shell.js): header and its followers move by the same transform, so no layout shift; the inset band stays painted */
  .kardio-shell [data-follow-header] { transition: transform .2s ease; }
  .kardio-shell[data-header="hidden"] .app-header { transform: translateY(calc(-1 * var(--header-h-sm))); }
  .kardio-shell[data-header="hidden"] [data-follow-header] { transform: translateY(calc(-1 * var(--header-h-sm))); }
  .kardio-shell .app-header .brand { flex: 0 1 auto; width: auto; min-width: 0; height: var(--header-control-h-lg); }
  .kardio-shell .app-header .brand > span:last-child { overflow: hidden; text-overflow: ellipsis; }
  .kardio-shell .app-header .header-app { flex: 1 1 auto; min-width: 0; height: var(--header-slot-h); }
  /* App slot wider than the room the row leaves (course "Bibliothek · Kapitel" at high zoom): it
     scrolls sideways (shell.js overflow cue) instead of widening the page (WCAG 1.4.10). The slot is
     44 px tall, so the 44 px hit areas inside it are not clipped. */
  .kardio-shell .app-header .header-app { overflow-x: auto; overscroll-behavior-x: contain; scrollbar-width: none; }
  .kardio-shell .app-header .header-app::-webkit-scrollbar { display: none; }
  .kardio-shell .app-header .header-app[data-overflow="end"]   { mask-image: linear-gradient(to right, #000 calc(100% - 24px), transparent); }
  .kardio-shell .app-header .header-app[data-overflow="start"] { mask-image: linear-gradient(to left, #000 calc(100% - 24px), transparent); }
  .kardio-shell .app-header .header-app[data-overflow="both"]  { mask-image: linear-gradient(to right, transparent, #000 24px, #000 calc(100% - 24px), transparent); }
  .kardio-shell .app-header .header-app { scroll-padding-inline: 24px; }
  /* The scroller clips everything outside its 44 px box, including a focus ring drawn around an
     item that fills the slot (Echo's view select) or touches its edge (Kurs "Bibliothek"): inside
     this slot the keyboard ring is drawn inside the item (3 px ring, -3 px offset; WCAG 2.4.7). */
  .kardio-shell .app-header .header-app a:focus-visible,
  .kardio-shell .app-header .header-app button:focus-visible,
  .kardio-shell .app-header .header-app select:focus-visible { outline-offset: -3px; }
  .kardio-shell .app-header .mode-tabs { flex: 0 1 auto; }
  .kardio-shell .app-header .mode-tab { padding: 0 10px; font-size: var(--text-sm); height: calc(var(--header-slot-h) - 2 * var(--space-1)); }
  .kardio-shell .app-header .header-select { flex: 1 1 auto; height: var(--header-control-h); }
  .kardio-shell .app-header .header-only-compact { display: inline-flex; }
  .kardio-shell .disclaimer { padding-left: calc(var(--header-pad-x-sm) + env(safe-area-inset-left, 0px)); padding-right: calc(var(--header-pad-x-sm) + env(safe-area-inset-right, 0px)); }
  .kardio-shell .disclaimer .eyebrow { display: none; }
}
@media (max-width: 767px), (max-width: 960px) and (max-height: 500px) {
  /* Only the mark is left: it never shrinks (a long view select would squeeze it). */
  .kardio-shell .app-header .brand { gap: 0; flex: 0 0 auto; }
  .kardio-shell .app-header .brand > span:last-child { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
  .kardio-shell .app-header .brand-mark { width: 34px; height: 34px; border-radius: 10px; }
  .kardio-shell .app-header .brand-mark svg { width: 24px; }
}
/* Phones (portrait): EKG Studio's mode tabs fit the slot. */
@media (max-width: 600px) {
  .kardio-shell .app-header .mode-tabs { gap: 2px; }
  .kardio-shell .app-header .mode-tab { padding: 0 5px; font-size: var(--text-small); }
}
@media (max-width: 600px), (max-width: 960px) and (max-height: 500px) {
  .kardio-shell .disclaimer { display: none; }   /* replacement: .stage-note per view */
  .kardio-shell .stage-note {
    display: block; margin: 0;
    padding: var(--space-3) calc(var(--header-pad-x-sm) + env(safe-area-inset-right, 0px)) var(--space-4) calc(var(--header-pad-x-sm) + env(safe-area-inset-left, 0px));
    color: var(--muted); font-family: var(--font-sans); font-size: var(--text-xs); line-height: 1.4;
  }
  /* ⋯ menu: the actions move into a disclosure panel under the button. */
  .kardio-shell .app-header .header-more { display: inline-flex; width: var(--header-control-h); padding: 0; }
  .kardio-shell .app-header .header-more svg { display: block; width: 20px; height: 20px; fill: currentColor; }
  .kardio-shell .app-header .header-actions { display: none; }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions {
    display: flex; flex-direction: column; align-items: stretch;
    position: absolute; top: calc(100% + 4px); right: calc(8px + env(safe-area-inset-right, 0px));
    width: min(280px, calc(100vw - 16px)); height: auto; margin: 0; padding: 8px; gap: 4px;
    background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-panel);
    box-shadow: var(--shadow); z-index: var(--z-menu);
  }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .header-btn {
    width: 100%; height: var(--hit-min); justify-content: flex-start; gap: 10px;
    padding: 0 12px; font-size: var(--text-body); text-align: left;
  }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .header-btn::after { content: none; }   /* rows are 44 px already */
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .header-btn.theme-btn { font-size: 17px; font-weight: 400; }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .header-btn.account-btn { display: flex; align-items: center; line-height: 1; }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .account-name { min-width: 0; }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .account-placeholder { width: 100%; height: var(--hit-min); }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .local-badge { display: none; }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .header-label {
    position: static; width: auto; height: auto; margin: 0; overflow: visible; clip: auto;
    font-size: var(--text-body); font-weight: 600;
  }
  /* Kurs: <label class="header-lang">Sprache <select class="header-btn"></label> as one row */
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .header-lang {
    display: flex; align-items: center; justify-content: space-between; gap: 12px;
    width: 100%; min-height: var(--hit-min); padding-left: 12px; color: var(--ink);
  }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .header-lang select.header-btn { flex: 0 1 auto; width: auto; padding-right: 26px; }
  /* Echo: the language list expands inline inside the panel */
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .lang { display: flex; flex-direction: column; align-items: stretch; width: 100%; }
  .kardio-shell[data-header-menu="open"] .app-header .header-actions .lang .menu { position: static; min-width: 0; margin-top: 4px; box-shadow: none; }
}
@media (max-width: 960px) and (max-height: 500px) {
  .kardio-shell .app-header .platform-nav .nav-ext { display: inline; margin-left: 2px; font-size: 10px; }
  /* Reflow (WCAG 1.4.10): on a landscape phone the five links fit; at 400 % zoom (320 × 256) they
     scroll sideways with the overflow cue instead of pushing ⋯ off screen. 44 px tall, so the
     links' 44 px hit areas are not clipped by the scroller. The app slot gives way first (it
     shrinks 1000× faster, its own tabs scroll) down to 88 px, so the links — the only platform
     switch in this tier — stay whole wherever they fit. */
  .kardio-shell .app-header .platform-nav {
    flex: 0 1 auto; min-width: 0; height: var(--header-control-h-lg);
    overflow-x: auto; overscroll-behavior-x: contain; scrollbar-width: none; scroll-padding-inline: 24px;
  }
  .kardio-shell .app-header .header-app { flex-shrink: 1000; min-width: 88px; }
  .kardio-shell .app-header .platform-nav::-webkit-scrollbar { display: none; }
  .kardio-shell .app-header .platform-nav[data-overflow="end"]   { mask-image: linear-gradient(to right, #000 calc(100% - 24px), transparent); }
  .kardio-shell .app-header .platform-nav[data-overflow="start"] { mask-image: linear-gradient(to left, #000 calc(100% - 24px), transparent); }
  .kardio-shell .app-header .platform-nav[data-overflow="both"]  { mask-image: linear-gradient(to right, transparent, #000 24px, #000 calc(100% - 24px), transparent); }
  /* The first and last link touch the scroller's edges: their keyboard ring is drawn inside. */
  .kardio-shell .app-header .platform-nav a:focus-visible { outline-offset: -3px; }
}
/* Keyboard focus inside a header scroller: no fade and no 24 px scroll padding while it is there,
   so the focused item is fully clear even where the scroller is narrower than item + 2 × 24 px
   (the 88 px app slot at 400 % zoom). Same specificity as the masks above, and later. */
.kardio-shell .app-header .mode-tabs:has(:focus-visible),
.kardio-shell .app-header .header-app:has(:focus-visible),
.kardio-shell .app-header .platform-nav:has(:focus-visible) { mask-image: none; scroll-padding-inline: 0; }
.kardio-shell .embed .stage-note,
.kardio-shell .echo-embed .stage-note { display: none; }
/* Invisible until the page has settled (shell.js): a late-rendering view must not shift it (CLS). */
.kardio-shell:not([data-shell-settled]) .stage-note { visibility: hidden; }

/* Touch: hit areas ≥ 44 × 44 px without changing a visible box (transparent ::after).
   Narrow items reach 44 px wide too: the side offset min(2px, 50% − 22px) centres a 44 px area
   on a narrow item ("EP", "Üben", ◐, ⋯), which then reaches over the 2–4 px gap and the edge of
   its neighbour; a wide item's area sits 2 px inside its own box (the box itself still takes the
   tap), so the narrow neighbour's area (z-index 1) wins that edge. Every item keeps ≥ 44 px. */
@media (hover: none) and (pointer: coarse) {
  .kardio-shell .app-header .platform-nav a,
  .kardio-shell .app-header .header-btn,
  .kardio-shell .app-header .header-link,
  .kardio-shell .app-header .header-check,
  .kardio-shell .app-header .mode-tab { position: relative; }
  .kardio-shell .app-header .platform-nav a::after { content: ""; position: absolute; z-index: 1; inset: -6px min(2px, calc(50% - 22px)); }  /* 32 + 2 × 6 = 44 tall */
  /* the offsets count from the padding box, inside the button's 1px border: 34 + 2 × 5 = 44 (⋯, ◐) */
  .kardio-shell .app-header .header-btn::after { content: ""; position: absolute; z-index: 1; inset: -5px min(2px, calc(50% - 22px)); }
  .kardio-shell .app-header .header-link::after { content: ""; position: absolute; inset: -4px -2px; }   /* Bibliothek */
  /* .mode-tabs' padding box is exactly 44 tall, so its overflow scroller does not clip this */
  .kardio-shell .app-header .mode-tab::after { content: ""; position: absolute; z-index: 1; inset: -4px min(2px, calc(50% - 22px)); }
  /* Echo "Vergleichs-Echo": the label row is 22 px tall on desktop and tablets in landscape */
  .kardio-shell .app-header .header-check::after { content: ""; position: absolute; inset: -11px 0; }
  .kardio-shell .app-header .header-select { font-size: 16px; }   /* iOS focus zoom (as before the shell) */
  /* Compact tier only: the box itself is 44 tall — pseudo-elements do not render on <select>
     (SHELL-06). Touch tablets in the desktop tier keep the desktop header boxes (36 px). */
  @media (max-width: 900px), (max-width: 960px) and (max-height: 500px) {
    .kardio-shell .app-header select.header-btn { height: var(--header-control-h-lg); font-size: 16px; }
    .kardio-shell .app-header .header-select { height: var(--header-control-h-lg); }
    .kardio-shell .app-header .header-check { min-height: var(--header-control-h-lg); padding: 0 8px; }
    .kardio-shell .app-header .header-check::after { content: none; }
  }
  /* Mark tier: the brand is only its 34 px mark — a 44 × 44 area around it. */
  @media (max-width: 767px), (max-width: 960px) and (max-height: 500px) {
    .kardio-shell .app-header .brand { position: relative; }
    .kardio-shell .app-header .brand::after { content: ""; position: absolute; inset: 0 -5px; }
  }
}
@media (prefers-reduced-motion: reduce) {
  .kardio-shell .app-header { transition: none; }
  .kardio-shell [data-follow-header] { transition: none; }
}

/* Learning subjects and simulator workspaces share native disclosures. */
.kardio-shell .app-header .platform-dropdown { position: relative; }
.kardio-shell .app-header .platform-dropdown > summary {
  display: flex; align-items: center; gap: 8px;
  min-height: var(--header-nav-h); padding: 0 10px;
  border-radius: var(--radius-input); color: var(--muted);
  font-size: var(--text-sm); font-weight: 500; cursor: pointer; list-style: none;
  white-space: nowrap;
}
.kardio-shell .app-header .platform-dropdown > summary::-webkit-details-marker { display: none; }
.kardio-shell .app-header .platform-dropdown > summary::after { content: "⌄"; }
.kardio-shell .app-header .platform-dropdown > summary:hover,
.kardio-shell .app-header .platform-dropdown[open] > summary { color: var(--ink); background: var(--surface-soft); }
.kardio-shell .app-header .platform-dropdown:has(a[aria-current="page"]) > summary { color: var(--accent-ink); background: var(--accent-soft); }
.kardio-shell .app-header .platform-dropdown > summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.kardio-shell .app-header .platform-dropdown-panel {
  position: absolute; top: calc(100% + 6px); left: 0; z-index: var(--z-menu);
  min-width: 210px; padding: 6px; border: 1px solid var(--line);
  border-radius: var(--radius-panel); background: var(--surface); box-shadow: var(--shadow);
}
.kardio-shell .app-header .platform-dropdown-panel a { display: flex; min-height: 44px; }
.kardio-shell .app-header .platform-dropdown-panel a::after { content: none; }
.kardio-shell .app-header:has(.platform-dropdown[open]) { z-index: var(--z-menu); }
/* Dropdown panels must escape the landscape header's former link scroller. */
.kardio-shell .app-header .platform-nav:has(.platform-dropdown) { overflow: visible; mask-image: none; }
@media (hover: none) and (pointer: coarse) {
  .kardio-shell .app-header .platform-dropdown > summary::before { content: ""; position: absolute; inset: -6px 0; }
}

/* Labels navigate; the remaining summary area toggles on touch/keyboard. */
.kardio-shell .app-header .platform-dropdown > summary { padding-left: 0; }
.kardio-shell .app-header .platform-dropdown > summary > a { color: inherit; }
.kardio-shell .app-header .platform-dropdown > summary::before { content: none; }
.kardio-shell .app-header .platform-dropdown-panel::before { content: ""; position: absolute; inset: -8px 0 auto; height: 8px; }

.kardio-shell .app-header .brand .beta-badge { display: inline-block; margin-left: 4px; padding: 1px 5px; border: 1px solid var(--accent); border-radius: 4px; color: var(--accent-ink); font-size: 9px; font-weight: 650; letter-spacing: .03em; vertical-align: 1px; }
@media (max-width: 767px), (max-width: 960px) and (max-height: 500px) {
  .kardio-shell .app-header .brand-mark { position: relative; }
  .kardio-shell .app-header .brand-mark::after { content: "Beta"; position: absolute; right: -8px; bottom: -5px; padding: 1px 3px; border: 1px solid var(--accent); border-radius: 3px; color: var(--accent-ink); background: var(--surface); font: 600 8px/1.2 var(--font-sans); }
}