/* V3 shares V2's controls; its opaque reading surfaces sit above a quiet, fixed backdrop. */
:root:is([data-design="v3"], [data-design="v4"]) {
  --m5-page: #edf1fa;
  --m5-surface: #fcfdff;
  --m5-surface-soft: #f2f5fc;
  --m5-surface-raised: #e7edf8;
  --m5-featured: #f2f5fc;
  --m5-ink: #19243e;
  --m5-text: #2d3b55;
  --m5-muted: #53627b;
  --m5-link: #354b98;
  --m5-border: #b1bdd3;
  --m5-border-soft: #d1daeb;
  --m5-border-strong: #667a9b;
  --m5-selected-bg: #e7edfc;
  --m5-selected-ink: #243c79;
  --m5-focus: #354b98;
  --m5-shadow: #253f7314;
  --v3-glow-blue: #90b2fb50;
  --v3-glow-violet: #c7a9f248;
  --v3-glow-teal: #84d4d936;
  --v3-glow-pearl: #ffffffd9;
  --v3-orbit-blue: #789ce1;
  --v3-orbit-violet: #ad89cf;
  --v3-orbit-light: #ffffff;
  --v3-nav: #f9fbfff0;
  --v3-panel: #fafcffd9;
  --v3-footer: #f2f5fce8;
  --v3-highlight: #ffffffc9;
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] {
  --m5-page: #090b0f;
  --m5-surface: #15181e;
  --m5-surface-soft: #191d24;
  --m5-surface-raised: #242a33;
  --m5-featured: #191d24;
  --m5-accent: #b3c3d5;
  --m5-accent-hover: #d0dbe6;
  --m5-on-accent: #141b24;
  --m5-ink: #dce0e5;
  --m5-text: #c8ccd2;
  --m5-muted: #a0a7b2;
  --m5-link: #a6b5dc;
  --m5-border: #49515e;
  --m5-border-soft: #2d333d;
  --m5-border-strong: #788596;
  --m5-selected-bg: #293345;
  --m5-selected-ink: #d6deec;
  --m5-focus: #a6b5dc;
  --m5-shadow: #00000040;
  --m5-cloud-1: #c8d0df;
  --m5-cloud-2: #d7a5b2;
  --m5-cloud-3: #a6b5dc;
  --m5-cloud-4: #a1c1c5;
  --m5-purple: #a3c9cb;
  --m5-purple-soft: #243b40;
  --m5-cloud-5: #a0a7b2;
  --m5-cloud-hover: #242a33;
  --m5-cloud-count: #293345;
  --m5-cloud-footer: #15181e;
  --v2-button-bg: #1b2028;
  --v2-cloud-bg: #15181e;
  --v2-group-edge: #49515e;
  --v2-share-bg: #202a35;
  --v2-share-hover: #2b3848;
  --v2-share-edge: #61758c;
  --v3-glow-blue: #324b701f;
  --v3-glow-violet: #3b55651c;
  --v3-glow-teal: #31565314;
  --v3-glow-pearl: #879aab05;
  --v3-orbit-blue: #687e9b;
  --v3-orbit-violet: #758d95;
  --v3-orbit-light: #a4b0bf;
  --v3-nav: #101317f2;
  --v3-panel: #15181ee6;
  --v3-footer: #101317eb;
  --v3-highlight: #c5ccd60c;
}

/* V1 borrows the luminous surfaces while keeping every original semantic color. */
:root[data-design="v1"] {
  --v3-glow-blue: color-mix(in srgb, var(--m5-blue) 16%, transparent);
  --v3-glow-violet: color-mix(in srgb, var(--m5-purple) 12%, transparent);
  --v3-glow-teal: color-mix(in srgb, var(--m5-coral) 7%, transparent);
  --v3-glow-pearl: color-mix(in srgb, var(--m5-surface) 85%, transparent);
  --v3-orbit-blue: var(--m5-blue);
  --v3-orbit-violet: var(--m5-purple);
  --v3-orbit-light: var(--m5-surface);
  --v3-nav: color-mix(in srgb, var(--m5-surface) 94%, transparent);
  --v3-panel: color-mix(in srgb, var(--m5-surface) 86%, transparent);
  --v3-highlight: color-mix(in srgb, var(--m5-surface) 78%, transparent);
}

:root[data-design="v1"][data-theme="dark"] {
  --v3-glow-blue: color-mix(in srgb, var(--m5-blue) 10%, transparent);
  --v3-glow-violet: color-mix(in srgb, var(--m5-purple) 8%, transparent);
  --v3-glow-teal: color-mix(in srgb, var(--m5-coral) 5%, transparent);
  --v3-glow-pearl: transparent;
  --v3-highlight: color-mix(in srgb, var(--m5-ink) 5%, transparent);
}

.site-backdrop {
  display: none;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) body {
  position: relative;
  isolation: isolate;
  min-height: 100svh;
  background: transparent;
}

/* Isolate the negative layer so it stays above the root canvas and below every control.
   A fixed element avoids mobile background-attachment quirks and needs no scroll handler. */
:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .site-backdrop {
  display: block;
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
  background:
    radial-gradient(ellipse at 12% 14%, var(--v3-glow-blue), transparent 53%),
    radial-gradient(ellipse at 91% 20%, var(--v3-glow-violet), transparent 49%),
    radial-gradient(ellipse at 83% 93%, var(--v3-glow-teal), transparent 52%),
    radial-gradient(ellipse at 46% 44%, var(--v3-glow-pearl), transparent 59%),
    var(--m5-page);
}

.site-backdrop svg {
  display: block;
  width: 100%;
  height: 100%;
  opacity: .68;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"])[data-theme="dark"] .site-backdrop svg {
  opacity: .22;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .navHead {
  background: var(--v3-nav);
  border-bottom-color: var(--m5-border-soft);
  box-shadow: 0 3px 18px var(--m5-shadow);
  backdrop-filter: blur(16px);
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .launch-join {
  background: var(--v3-panel);
  border-color: var(--m5-border-soft);
  border-radius: 16px;
  box-shadow: inset 0 1px var(--v3-highlight), 0 8px 24px var(--m5-shadow);
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .story-watch,
:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .story-panel,
:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .transcript-panel {
  border-color: var(--m5-border-soft);
  border-radius: 12px;
  box-shadow: inset 0 1px var(--v3-highlight), 0 8px 24px var(--m5-shadow);
}

/* Let V1's fixed backdrop continue through the footer instead of ending at a solid band. */
:root[data-design="v1"] .site-footer {
  margin-top: 16px;
  padding: 24px 20px;
  border-top-color: color-mix(in srgb, var(--m5-border-soft) 60%, transparent);
  background: linear-gradient(transparent, color-mix(in srgb, var(--m5-surface) 70%, transparent));
}

:root:is([data-design="v3"], [data-design="v4"]) .site-footer {
  --m5-link: #354b98;
  --m5-muted: #53627b;
  --m5-focus: #354b98;
  color: var(--m5-text);
  background: var(--v3-footer);
  border-top-color: var(--m5-border-soft);
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] .site-footer {
  --m5-link: #a6b5dc;
  --m5-muted: #a0a7b2;
  --m5-focus: #a6b5dc;
}

:root:is([data-design="v3"], [data-design="v4"]) .site-footer a {
  color: var(--m5-link);
}

:root:is([data-design="v3"], [data-design="v4"]) .site-footer a:hover {
  color: var(--m5-ink);
}

@media (max-width: 600px) {
  .site-backdrop svg {
    opacity: .42;
  }
}

@media print, (forced-colors: active) {
  :root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .site-backdrop {
    display: none;
  }
}

:root:is([data-design="v3"], [data-design="v4"]) :is(.playlist-playback, .story-transition-status, .details-loading, .story-unavailable) {
  padding: 12px 16px;
  border: 1px solid var(--m5-border-soft);
  border-radius: 10px;
  background: var(--m5-surface);
}
:root:is([data-design="v2"], [data-design="v3"], [data-design="v4"]) .reaction-option:not(.selected) {
  border-color: var(--m5-border-soft);
  background: var(--m5-surface);
}

:root:is([data-design="v3"], [data-design="v4"]) :is(.transcript-line p, .transcript-text p) {
  line-height: 1.55;
}

:root:is([data-design="v3"], [data-design="v4"]) .transcript-line {
  padding-block: 10px;
}

:root:is([data-design="v3"], [data-design="v4"]) .transcript-text p + p {
  margin-top: .75em;
}

:root:is([data-design="v3"], [data-design="v4"]) .transcript-line .speaker {
  margin-bottom: 4px;
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] :is(.transcript-line p, .transcript-text p) {
  color: var(--m5-text);
  font-weight: 400;
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] .transcript-line[aria-current="true"] p {
  color: color-mix(in srgb, var(--m5-text) 90%, var(--m5-link));
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] :is(.story-heading h1, .shelf-heading h3) {
  font-weight: 550;
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] :is(.story-synopsis h2, .transcript-heading h2, .related-topics h2, .reading-panel h2, .reading-group h3, .reaction-strip h2, .share-invitation h2) {
  font-weight: 550;
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] :is(.reading-card-title, .reading-card-action, .story-author strong, .transcript-line .speaker) {
  font-weight: 500;
}

:root:is([data-design="v3"], [data-design="v4"])[data-theme="dark"] :is(.cloud-word, .cloud-total strong) {
  font-weight: 600;
}

/* Compact filmstrips keep more stories and related reading in view together. */
:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .explore-stories {
  padding-top: 8px;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .topic-row {
  margin-bottom: 0;
  padding: 6px 8px 10px;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .shelf-heading {
  padding-bottom: 0;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .shelf-track {
  gap: 10px;
  padding-top: 4px;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) :is(.shelf-card, .shelf-skeleton) {
  flex-basis: clamp(164px, 16vw, 190px);
  max-width: none;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .shelf-caption {
  padding: 6px 9px 8px;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .shelf-caption h4 {
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  overflow: hidden;
  margin: 0;
  font-size: .8rem;
  font-weight: 400;
  line-height: 1.35;
  min-height: 2.7em;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .shelf-subtopic {
  margin-bottom: 3px;
  font-size: .65rem;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .topic-shelf .play-icon {
  width: 24px;
  height: 24px;
  bottom: 8px;
  left: 8px;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .topic-shelf .duration {
  right: 8px;
  bottom: 8px;
  font-size: .65rem;
}

/* The old loading tile height must not stretch every card in a short row. */
:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .load-more {
  flex-basis: 110px;
  min-height: 0;
  font-size: .8rem;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .shelf-skeleton {
  min-height: 0;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .shelf-skeleton > span {
  height: 8px;
  margin: 8px 9px;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .related-reading {
  padding-bottom: 0;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .topic-shelf .reading-compact {
  padding-top: 4px;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .topic-shelf .reading-chip {
  border-color: color-mix(in srgb, var(--reading-chip-color) 40%, var(--m5-border));
  background: color-mix(in srgb, var(--reading-chip-color) 20%, var(--m5-surface));
  color: var(--m5-ink);
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .topic-shelf .reading-chip:hover {
  border-color: color-mix(in srgb, var(--reading-chip-color) 65%, var(--m5-border));
  background: color-mix(in srgb, var(--reading-chip-color) 30%, var(--m5-surface));
}

@media (max-width: 600px) {
  :root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) :is(.shelf-card, .shelf-skeleton) {
    flex-basis: clamp(148px, 44vw, 180px);
  }
}

/* The featured videos share V3's native canvas. Keep shading inside each tile;
   opaque clipped edges meet during a layer exchange without exposing a faded bar. */
:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) :is(.featured-stories, .story-carousel) {
  background: transparent;
  color: var(--m5-text);
  border-bottom-color: var(--m5-border-soft);
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .story-card {
  mask-image: none;
  clip-path: inset(0 var(--clip-right, 0%) 0 var(--clip-left, 0%));
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .story-card::after {
  background: #08090b;
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) :is(.featured-topics a, .empty-state a) {
  color: var(--m5-link);
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) .featured-topics a:hover {
  color: var(--m5-ink);
}

:root:is([data-design="v1"], [data-design="v3"], [data-design="v4"]) :is(.featured-topics a::after, .carousel-status, .story-carousel .load-more) {
  color: var(--m5-muted);
}