*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', Aptos, Arial, sans-serif;
  background: var(--white);
  color: var(--navy);
  overflow-x: hidden;
}

/* ── FIXED TOP BAR ─────────────────────────────────────────── */
.top-bar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--bar-h);
  background: var(--navy);
  display: flex;
  align-items: center;
  padding: 0 28px;
  gap: 20px;
  z-index: 200;
  border-bottom: 4px solid var(--dandelion);
}

.top-bar .back-link {
  color: var(--dandelion);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
}
.top-bar .back-link:hover { text-decoration: underline; }

.top-bar .bar-title {
  color: var(--white);
  font-size: 1rem;
  font-weight: 700;
  flex: 1;
}

/* Section nav dots — one per section, top-right */
.section-dots {
  display: flex;
  gap: 8px;
  align-items: center;
}
.section-dots a {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,0.3);
  display: block;
  transition: background 0.2s;
}
.section-dots a.active,
.section-dots a:hover { background: var(--dandelion); }

/* Gold progress bar */
.progress-bar {
  position: fixed;
  top: var(--bar-h);
  left: 0;
  height: 3px;
  width: 0%;
  background: var(--dandelion);
  z-index: 201;
  transition: width 0.08s linear;
}

/* ── HERO ──────────────────────────────────────────────────── */
.hero {
  min-height: 100vh;
  background: var(--navy);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--bar-h) + 40px) 40px 60px;
}

.hero .eyebrow {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--dandelion);
  margin-bottom: 20px;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.6rem);
  font-weight: 800;
  color: var(--white);
  line-height: 1.15;
  max-width: 800px;
  margin-bottom: 24px;
}

.hero h1 span {
  color: var(--dandelion);
}

.hero p {
  font-size: 1.15rem;
  color: var(--sky);
  max-width: 560px;
  line-height: 1.7;
  margin-bottom: 40px;
}

.hero .scroll-hint {
  color: rgba(255,255,255,0.4);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.scroll-hint .arrow {
  width: 24px;
  height: 24px;
  border-right: 2px solid rgba(255,255,255,0.3);
  border-bottom: 2px solid rgba(255,255,255,0.3);
  transform: rotate(45deg);
  animation: bounce 1.6s ease-in-out infinite;
}

@keyframes bounce {
  0%, 100% { transform: rotate(45deg) translateY(0); }
  50%       { transform: rotate(45deg) translateY(6px); }
}

/* ── INTRO OVERLAY ─────────────────────────────────────────── */
.intro-overlay {
  position: fixed;
  inset: 0;
  background: var(--navy);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px;
  z-index: 150;
  transition: opacity 0.8s ease, visibility 0.8s ease;
}

body.has-scrolled .intro-overlay {
  opacity: 0;
  visibility: hidden;
}

.intro-overlay h1 {
  font-size: clamp(2.2rem, 6vw, 3.8rem);
  font-weight: 800;
  color: var(--white);
  line-height: 1.15;
  max-width: 800px;
  margin-bottom: 32px;
}

.intro-overlay h1 span {
  color: var(--dandelion);
}

.intro-overlay .intro-hint {
  color: rgba(255,255,255,0.5);
  font-size: 0.85rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  margin-top: 40px;
}

.intro-hint .arrow {
  width: 28px;
  height: 28px;
  border-right: 2px solid rgba(255,255,255,0.4);
  border-bottom: 2px solid rgba(255,255,255,0.4);
  transform: rotate(45deg);
  animation: bounce 1.6s ease-in-out infinite;
}

/* ── MEASUREMENT SCENE (pencil + ruler) ─────────────────────── */
.measurement-scene {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  z-index: -1;
}

.pencil-image, .ruler-image {
  position: absolute;
  object-fit: contain;
}

.pencil-image {
  height: 380px;
  left: -200px;
  bottom: -80px;
  animation: pencil-scroll 0.9s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

.ruler-image {
  height: 480px;
  right: -240px;
  bottom: -100px;
  animation: ruler-scroll 0.9s cubic-bezier(0.22, 1, 0.36, 1) forwards;
  animation-delay: 0.14s;
}

@keyframes pencil-scroll {
  from { left: -200px; opacity: 0; }
  to   { left: -40px; opacity: 1; }
}

@keyframes ruler-scroll {
  from { right: -240px; opacity: 0; }
  to   { right: -60px; opacity: 1; }
}

/* Ruler jiggle at pencil measurement point */
.ruler-image.jiggle {
  animation: ruler-jiggle 0.4s ease-in-out infinite;
}

@keyframes ruler-jiggle {
  0%, 100% { transform: translateX(0); }
  50%      { transform: translateX(2px); }
}

/* ── FIXED BACKGROUND STAGE ────────────────────────────────────
   The stage sits behind everything and never moves.
   Cards float above it and animate as the user scrolls.
   Background color transitions as the user scrolls through sections.
──────────────────────────────────────────────────────────── */
.stage {
  position: fixed;
  inset: 0;
  background: #001E5F;
  z-index: 0;
  transition: background-color 0.6s ease;
}

/* Section-specific background colors */
.stage.bg-sec-why,
.stage.bg-sec-temp,
.stage.bg-sec-grav,
.stage.bg-sec-meas,
.stage.bg-sec-acc,
.stage.bg-sec-dist,
.stage.bg-sec-std,
.stage.bg-sec-sem,
.stage.bg-sec-prop,
.stage.bg-sec-summary,
.stage.bg-sec-poisson { background: #001E5F; }

/* Subtle radial glow in the center of the stage */
.stage::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 70% 60% at 50% 50%,
                rgba(0,102,253,0.12) 0%, transparent 70%);
  pointer-events: none;
}

/* ── SCROLL STOP ────────────────────────────────────────────────
   Each stop is a tall scroll container (300vh).
   The inner .sticky-frame pins to the viewport for the middle
   200vh of that scroll, giving plenty of time to see the cards
   before they exit.

   How the exit works: JS reads how far past the "hold zone"
   the user has scrolled, then applies scale() + opacity to
   .card-pair, shrinking the cards into the distance.
──────────────────────────────────────────────────────────── */
.stop {
  position: relative;
  height: 300vh;          /* tall enough to scroll through */
  z-index: 1;
}

.sticky-frame {
  position: sticky;
  top: var(--bar-h);
  height: calc(100vh - var(--bar-h));
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;       /* clips cards during slide-in */
  pointer-events: none;   /* let scroll pass through to the stop */
}

/* The pair of cards — JS drives scale + opacity on exit */
.card-pair {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
  width: 100%;
  max-width: 1100px;
  padding: 0 48px;
  pointer-events: all;
  /* transform-origin center so scale() shrinks toward the middle */
  transform-origin: center center;
  transition: transform 0.08s linear, opacity 0.08s linear;
}

/* ── CARDS ──────────────────────────────────────────────────────
   Each card is a floating rectangle with rounded corners and a
   layered shadow — close tight shadow for depth, far diffuse
   shadow for the hover/lift illusion.
──────────────────────────────────────────────────────────── */
.panel {
  flex: 1;
  max-width: 460px;
  min-width: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 48px 44px;
  border-radius: 20px;
  box-shadow:
    0  4px  16px rgba(0,  0,  0, 0.25),
    0 28px  60px rgba(0,  0,  0, 0.40);

  /* Entry animation — JS adds .stop-active to the .stop,
     which triggers the transition below */
  transition: transform 0.9s cubic-bezier(0.22, 1, 0.36, 1),
              opacity  0.9s ease;
}

/* Cards start off-screen left/right, opacity 0 */
.panel-left  { transform: translateX(-120px); opacity: 0; }
.panel-right { transform: translateX( 120px); opacity: 0; }

/* When the stop becomes active, cards slide to center */
.stop-active .panel-left,
.stop-active .panel-right {
  transform: translateX(0);
  opacity: 1;
}

/* Right card follows left with a slight delay */
.stop-active .panel-right { transition-delay: 0.14s; }

/* ── CARD COLOR VARIANTS ────────────────────────────────────── */
.panel.navy      { background: var(--navy);      color: var(--white); }
.panel.dandelion { background: var(--dandelion);  color: var(--navy); }
.panel.sky       { background: var(--sky);        color: var(--navy); }
.panel.butter    { background: var(--butter);     color: var(--navy); }
.panel.white     { background: var(--white);      color: var(--navy); }
.panel.meliora   { background: var(--meliora);    color: var(--white); }

/* ── PANEL TYPOGRAPHY ──────────────────────────────────────── */
.panel .section-tag {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  opacity: 0.6;
  margin-bottom: 16px;
}

.panel h2 {
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
}

.panel .headline-stat {
  font-size: clamp(1.1rem, 2vw, 1.5rem);
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 20px;
}

.panel p {
  font-size: 1rem;
  line-height: 1.75;
  opacity: 0.88;
  max-width: 480px;
}

.panel p + p { margin-top: 12px; }

/* Accent bar above heading */
.panel .accent-bar {
  width: 48px;
  height: 5px;
  border-radius: 3px;
  margin-bottom: 20px;
}

.panel.navy .accent-bar      { background: var(--dandelion); }
.panel.dandelion .accent-bar { background: var(--navy); }
.panel.sky .accent-bar       { background: var(--navy); }
.panel.butter .accent-bar    { background: var(--navy); }
.panel.silver .accent-bar    { background: var(--navy); }
.panel.white .accent-bar     { background: var(--azure); }
.panel.meliora .accent-bar   { background: var(--dandelion); }

/* ── GRAPHIC PANEL ─────────────────────────────────────────── */
.panel.graphic {
  align-items: center;
  justify-content: center;
  padding: 40px;
}

.panel.graphic svg {
  width: 100%;
  max-width: 400px;
  height: auto;
}

/* ── NEWSPAPER CLIPPING style for poll example ─────────────── */
.clipping {
  background: var(--white);
  border: 1px solid #ccc;
  border-radius: 4px;
  padding: 24px 28px;
  box-shadow: 4px 4px 0 rgba(0,0,0,0.08);
  max-width: 380px;
}

.clipping .paper-name {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--charcoal);
  border-bottom: 2px solid var(--navy);
  padding-bottom: 6px;
  margin-bottom: 12px;
}

.clipping .headline {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--navy);
  line-height: 1.3;
  margin-bottom: 14px;
}

/* Poll bars */
.poll-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
  font-size: 0.88rem;
}

.poll-label { width: 60px; font-weight: 600; color: var(--navy); }

.poll-bar-wrap {
  flex: 1;
  height: 22px;
  background: var(--silver);
  border-radius: 3px;
  overflow: visible;
  position: relative;
}

.poll-bar {
  height: 100%;
  border-radius: 3px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding-right: 6px;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--white);
  position: relative;
}

/* Error bar overlay */
.poll-bar::after {
  content: '';
  position: absolute;
  right: -1px;
  top: 50%;
  transform: translateY(-50%);
  width: 2px;
  height: 140%;
  background: var(--charcoal);
}

/* Horizontal error whiskers */
.poll-bar::before {
  content: '';
  position: absolute;
  right: -8px;
  top: 50%;
  transform: translateY(-50%);
  width: 14px;
  height: 2px;
  background: var(--charcoal);
}

.clipping .caption {
  font-size: 0.75rem;
  color: var(--charcoal);
  margin-top: 10px;
  font-style: italic;
}

.clipping .verdict {
  margin-top: 12px;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--meliora);
  background: var(--sky);
  border-radius: 3px;
  padding: 6px 10px;
}

/* ── TEMPERATURE graphic ───────────────────────────────────── */
.temp-graphic {
  background: var(--white);
  border-radius: 6px;
  padding: 20px 24px;
  max-width: 380px;
  box-shadow: 0 2px 16px rgba(0,30,95,0.1);
}

.temp-graphic .tg-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--charcoal);
  margin-bottom: 12px;
}

.temp-bar-wrap {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.temp-row {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.82rem;
}

.temp-year { width: 36px; font-weight: 700; color: var(--navy); }

.temp-bar {
  height: 24px;
  border-radius: 3px;
  display: flex;
  align-items: center;
  padding: 0 8px;
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--white);
  position: relative;
  transition: width 0.6s ease;
}

/* ── MOBILE ────────────────────────────────────────────────── */
@media (max-width: 720px) {
  /* On mobile the sticky + tall-scroll effect is too awkward;
     fall back to a simple stacked scroll */
  .stop        { height: auto; }
  .sticky-frame {
    position: relative;
    top: auto;
    height: auto;
    flex-direction: column;
    padding: 48px 20px;
    gap: 24px;
    overflow: visible;
  }
  .card-pair {
    flex-direction: column;
    padding: 0;
    gap: 24px;
  }
  .panel {
    max-width: 100%;
    padding: 36px 28px;
  }
  .panel-left, .panel-right {
    transform: translateY(50px);
    opacity: 0;
  }
  .stop-active .panel-left,
  .stop-active .panel-right {
    transform: translateY(0);
    opacity: 1;
  }
}