/* howbigis.org — static educational page
   Palette ported from ../VoteDown (vd.css): magenta / purple / indigo with mint + pink pops. */
:root {
  /* VoteDown source tokens */
  --vd-magenta: #E227FF;
  --vd-pink-bright: #EC38FF;
  --vd-pink-hot: #E20F81;
  --vd-purple-deep: #491D88;
  --vd-purple-ink: #100B16;
  --vd-indigo: #1D2C98;
  --vd-indigo-soft: #6fa8dc;
  --vd-mint: #1CE5C3;
  --vd-pink-soft: #F3C5F8;
  --vd-gray-100: #F3F5F8;
  --vd-gray-200: #EEF1F5;
  --vd-gray-300: #D9DFE5;

  /* Mapped roles */
  --bg: var(--vd-gray-100);
  --bg-alt: var(--vd-gray-200);
  --surface: #ffffff;
  --text: var(--vd-purple-ink);
  --text-soft: var(--vd-purple-deep);
  --muted: #6b6577;
  --border: var(--vd-gray-300);
  --accent: var(--vd-magenta);
  --accent-dim: #AD00FF;
  --accent-deep: var(--vd-purple-deep);
  --accent-soft: var(--vd-pink-soft);
  --secondary: var(--vd-indigo);
  --highlight: var(--vd-mint);
  --ring: rgba(226, 39, 255, 0.45);
  --shadow-sm: 0 1px 2px rgba(73, 29, 136, 0.08);
  --shadow: 0 6px 18px rgba(73, 29, 136, 0.12);
  --shadow-lg: 0 24px 60px rgba(73, 29, 136, 0.18);
  --radius: 14px;
  --radius-sm: 10px;
  --font: system-ui, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms;
    animation-iteration-count: 1;
    transition-duration: 0.01ms;
  }
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--text);
  background-color: var(--bg);
  background-image:
    radial-gradient(circle at 12% 8%, rgba(226, 39, 255, 0.22), transparent 42%),
    radial-gradient(circle at 88% 14%, rgba(29, 44, 152, 0.20), transparent 48%),
    radial-gradient(circle at 78% 78%, rgba(226, 15, 129, 0.18), transparent 46%),
    radial-gradient(circle at 18% 88%, rgba(28, 229, 195, 0.16), transparent 48%);
  background-attachment: fixed;
  background-repeat: no-repeat;
  -webkit-font-smoothing: antialiased;
}

.skip-link {
  position: absolute;
  left: -9999px;
  z-index: 9999;
  padding: 0.75rem 1rem;
  background: var(--text);
  color: #fff;
  text-decoration: none;
  border-radius: 0 0 var(--radius) 0;
}

.skip-link:focus {
  left: 0;
  top: 0;
}

.wrap {
  width: min(1180px, 100% - 2rem);
  margin-inline: auto;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Header */
.site-header {
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.78);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: inherit;
}

.brand img {
  height: 2.25rem;
  width: auto;
  display: block;
}

/* Hero */
.hero {
  padding: clamp(2.5rem, 6vw, 4rem) 0 1rem;
  text-align: center;
}

.hero h1 {
  margin: 0 0 1rem;
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.1;
  background: linear-gradient(120deg, var(--vd-indigo) 0%, var(--vd-purple-deep) 45%, var(--vd-magenta) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero .lede {
  margin: 0 auto;
  max-width: 56rem;
  font-size: clamp(1rem, 1.6vw, 1.125rem);
  color: var(--text-soft);
  line-height: 1.7;
}

.hero .lede strong {
  color: var(--accent-deep);
  font-weight: 700;
}

/* Dimension picker */
.dimension-section {
  margin: 2rem auto 1.25rem;
  text-align: center;
}

.dimension-picker {
  display: inline-flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  box-shadow: var(--shadow-sm);
}

.chip {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 1.1rem;
  border: 1px solid transparent;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease, transform 0.18s ease;
}

.chip:hover:not([disabled]):not(.is-active) {
  color: var(--text);
  background: var(--bg-alt);
}

.chip:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.chip.is-active {
  background: linear-gradient(120deg, var(--vd-magenta) 0%, var(--vd-purple-deep) 100%);
  color: #fff;
  box-shadow: 0 8px 20px -6px var(--ring);
}

.chip[disabled] {
  cursor: not-allowed;
  opacity: 0.7;
}

.chip__icon {
  width: 1.1rem;
  height: 1.1rem;
  flex-shrink: 0;
}

.chip__badge {
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 0.15rem 0.45rem;
  border-radius: 999px;
  background: var(--bg-alt);
  color: var(--muted);
  border: 1px solid var(--border);
}

.dimension-hint {
  margin: 0.85rem 0 0;
  font-size: 0.85rem;
  color: var(--muted);
}

/* Carousel */
.carousel-section {
  margin-bottom: 3rem;
}

.main-swiper {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  position: relative;
  --swiper-theme-color: var(--accent);
}

.swiper-wrapper {
  align-items: stretch;
}

.swiper-slide {
  height: auto;
}

.slide-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 0;
  background: var(--surface);
  height: 100%;
  min-height: clamp(840px, 95vh, 1200px);
}

.slide-card--pair {
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr) minmax(0, 1fr);
}

.slide-image {
  position: relative;
  background: #0b1220;
  overflow: hidden;
  width: 100%;
  height: 100%;
}

.slide-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  display: block;
}

.slide-text {
  padding: clamp(1.5rem, 3vw, 2.5rem);
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: var(--surface);
}

.slide-eyebrow {
  margin: 0 0 0.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent-deep);
}

.slide-title {
  margin: 0 0 0.5rem;
  font-size: clamp(1.4rem, 2.6vw, 1.85rem);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.2;
  color: var(--text);
}

.slide-meta {
  margin: 0 0 1rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.slide-text p:not(.slide-eyebrow):not(.slide-meta) {
  margin: 0 0 0.85rem;
  color: var(--text-soft);
}

.slide-text p:last-child {
  margin-bottom: 0;
}

@media (max-width: 860px) {
  .slide-card {
    grid-template-columns: 1fr;
    min-height: 0;
  }

  .slide-image {
    height: clamp(640px, 95vh, 1040px);
  }

  .slide-card--pair .slide-image {
    height: clamp(320px, 45vh, 480px);
  }

  .slide-text {
    padding: 1.25rem 1.25rem 1.5rem;
  }
}

/* Pair-slide center column: connector + writeup */
.slide-text--center {
  text-align: center;
  align-items: center;
}

.slide-text--center > * {
  max-width: 32rem;
}

.connector {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  width: 100%;
  margin: 0.75rem 0 1.25rem;
}

.connector__line {
  flex: 1;
  height: 0;
  border-top: 2px dashed var(--accent);
  opacity: 0.7;
}

.connector__chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  background: linear-gradient(120deg, var(--vd-magenta), var(--vd-purple-deep));
  color: #fff;
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  white-space: nowrap;
  box-shadow: 0 6px 18px -6px var(--ring);
}

.connector__chip svg {
  width: 0.95rem;
  height: 0.95rem;
}

@media (max-width: 860px) {
  .connector {
    flex-direction: column;
    margin: 0.75rem auto 1rem;
    gap: 0.45rem;
  }

  .connector__line {
    width: 0;
    height: 24px;
    border-top: 0;
    border-left: 2px dashed var(--accent);
    flex: none;
  }
}

/* Placeholder image cards (used when real photos aren't ready yet) */
.slide-image--placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  text-align: center;
  padding: 2rem 1.25rem;
  color: #fff;
  background: linear-gradient(160deg, var(--vd-purple-deep) 0%, var(--vd-indigo) 100%);
}

.slide-image--placeholder.is-end {
  background: linear-gradient(160deg, var(--vd-magenta) 0%, var(--vd-pink-hot) 100%);
}

.slide-image--placeholder svg {
  width: clamp(64px, 14vw, 128px);
  height: auto;
  opacity: 0.92;
}

.slide-image--placeholder .placeholder-label {
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  opacity: 0.85;
  margin: 0;
  font-weight: 700;
}

.slide-image--placeholder .placeholder-name {
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  font-weight: 800;
  margin: 0;
  letter-spacing: -0.01em;
}

/* Hidden source decks for non-active dimensions (kept in HTML source for SEO) */
.deck-source {
  display: none;
}

/* Swiper navigation buttons (overlay on image) */
.main-swiper .swiper-button-prev,
.main-swiper .swiper-button-next {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(15, 23, 42, 0.55);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(6px);
  transition: background 0.2s ease, transform 0.2s ease, opacity 0.2s ease;
  margin-top: 0;
  top: 50%;
  transform: translateY(-50%);
  cursor: pointer;
}

.main-swiper .swiper-button-prev {
  left: 16px;
}

.main-swiper .swiper-button-next {
  right: 16px;
}

.main-swiper .swiper-button-prev:hover,
.main-swiper .swiper-button-next:hover {
  background: rgba(15, 23, 42, 0.8);
}

.main-swiper .swiper-button-prev:focus-visible,
.main-swiper .swiper-button-next:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 2px;
}

.main-swiper .swiper-button-prev::after,
.main-swiper .swiper-button-next::after {
  font-size: 18px;
  font-weight: 800;
}

.main-swiper .swiper-button-disabled {
  opacity: 0;
  pointer-events: none;
}

/* Pagination dots */
.main-swiper .swiper-pagination {
  bottom: 14px;
}

.main-swiper .swiper-pagination-bullet {
  width: 9px;
  height: 9px;
  background: rgba(255, 255, 255, 0.5);
  opacity: 1;
  transition: background 0.2s ease, transform 0.2s ease;
}

.main-swiper .swiper-pagination-bullet-active {
  background: #fff;
  transform: scale(1.2);
}

@media (max-width: 860px) {
  .main-swiper .swiper-pagination-bullet {
    background: rgba(15, 23, 42, 0.35);
  }

  .main-swiper .swiper-pagination-bullet-active {
    background: var(--accent-deep);
  }
}

/* Facts */
.facts {
  margin-bottom: 3rem;
  text-align: center;
}

.facts h2 {
  font-size: clamp(1.4rem, 3vw, 1.75rem);
  margin: 0 0 0.5rem;
  letter-spacing: -0.01em;
}

.facts-sub {
  margin: 0 auto 1.5rem;
  max-width: 40rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.facts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.fact-card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.25rem;
  box-shadow: var(--shadow-sm);
  text-align: left;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  overflow: hidden;
}

.fact-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: linear-gradient(90deg, var(--vd-magenta), var(--vd-pink-hot), var(--vd-indigo));
}

.fact-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.fact-card strong {
  display: block;
  font-size: 1.6rem;
  font-weight: 800;
  background: linear-gradient(120deg, var(--vd-purple-deep), var(--vd-magenta));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  letter-spacing: -0.01em;
  margin-bottom: 0.25rem;
}

.fact-card span {
  font-size: 0.9rem;
  color: var(--muted);
}

/* FAQ */
.faq {
  margin-bottom: 3rem;
}

.faq h2 {
  text-align: center;
  font-size: clamp(1.4rem, 3vw, 1.75rem);
  margin: 0 0 1.5rem;
  letter-spacing: -0.01em;
}

.faq-list {
  max-width: 44rem;
  margin: 0 auto;
}

.faq details {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 0.75rem;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.faq summary {
  padding: 1rem 1.25rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary::after {
  content: "+";
  color: var(--accent);
  font-weight: 700;
  font-size: 1.25rem;
  line-height: 1;
  transition: transform 0.2s ease;
}

.faq details[open] summary::after {
  content: "−";
}

.faq .answer {
  padding: 0 1.25rem 1.25rem;
  margin: 0;
  color: var(--text-soft);
  border-top: 1px solid var(--border);
  padding-top: 0.85rem;
}

/* Footer / share */
.site-footer {
  padding: 2.5rem 0 3rem;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.share h2 {
  text-align: center;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--muted);
  margin: 0 0 1rem;
}

.share-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem;
}

.share-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--bg);
  color: var(--muted);
  cursor: pointer;
  text-decoration: none;
  transition: background 0.18s ease, border-color 0.18s ease, color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}

.share-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

.share-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.share-icon {
  width: 1.15rem;
  height: 1.15rem;
  display: block;
}

.share-btn[data-share-network="twitter"]:hover {
  background: #0f0f0f;
  border-color: #0f0f0f;
  color: #fff;
}

.share-btn[data-share-network="facebook"]:hover {
  background: #1877f2;
  border-color: #1877f2;
  color: #fff;
}

.share-btn[data-share-network="linkedin"]:hover {
  background: #0a66c2;
  border-color: #0a66c2;
  color: #fff;
}

.share-btn[data-share-network="reddit"]:hover {
  background: #ff4500;
  border-color: #ff4500;
  color: #fff;
}

#share-native:hover,
#share-copy:hover {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent-deep);
}

.copy-status {
  width: 100%;
  text-align: center;
  font-size: 0.85rem;
  color: var(--accent-deep);
  margin: 0.6rem 0 0;
  min-height: 1.25rem;
}

.colophon {
  text-align: center;
  margin-top: 1.5rem;
  font-size: 0.875rem;
  color: var(--muted);
}

.colophon a {
  color: var(--accent-deep);
  text-decoration: none;
  font-weight: 600;
}

.colophon a:hover {
  text-decoration: underline;
}