:root {
  --wf-bg: #ffffff;
  --wf-text: #111827;
  --wf-muted: #374151;
  --wf-border: #000000;
  --wf-radius: 12px;
  --wf-pad-x: clamp(0.9rem, 3.5vw, 1.5rem);
  --wf-max-width: 960px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body.birthday-workflow {
  min-height: 100vh;
  min-height: 100dvh;
  background: var(--wf-bg);
  color: var(--wf-text);
  padding-inline: var(--wf-pad-x);
}

.wf-shell {
  width: min(100%, var(--wf-max-width));
  margin-inline: auto;
}

.wf-stage {
  min-height: 100vh;
  min-height: 100dvh;
}

.wf-card {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  border-radius: var(--wf-radius);
}

.wf-cta {
  min-height: 44px;
  border: 2px solid var(--wf-border);
  border-radius: 999px;
  background: #000000;
  color: #ffffff;
  font-weight: 700;
  padding: 0.7rem 1.2rem;
  cursor: pointer;
  touch-action: manipulation;
  transition:
    background-color 180ms ease,
    color 180ms ease,
    transform 140ms ease;
}

.wf-cta:hover {
  background: #ffffff;
  color: #000000;
}

.wf-cta:active {
  transform: scale(0.97);
}

.wf-hidden {
  display: none;
}

.wf-intro {
  position: relative;
  display: grid;
  place-items: center;
  text-align: center;
  min-height: 100vh;
  min-height: 100dvh;
  overflow: hidden;
}

.wf-intro-line {
  margin: 0;
  min-height: 1.5em;
  font-size: clamp(2rem, 6.5vw, 3.4rem);
  color: var(--wf-text);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.015em;
  max-width: min(92vw, 980px);
}

#introAdvanceButton {
  position: fixed;
  left: 50%;
  top: 56%;
  transform: translateX(-50%);
  min-width: clamp(190px, 30vw, 300px);
  min-height: clamp(56px, 8.5vw, 72px);
  padding: clamp(0.85rem, 2.4vw, 1.15rem) clamp(1.45rem, 3.8vw, 2.25rem);
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  line-height: 1;
  z-index: 10;
}

#introAdvanceButton.wf-pop {
  transform: translateX(-50%) scale(0.96);
}

#introAdvanceButton.wf-floating {
  transform: none;
}

#introAdvanceButton.wf-floating.wf-pop {
  transform: scale(0.96);
}

@media (max-width: 640px) {
  .wf-intro-line {
    font-size: clamp(1.7rem, 8vw, 2.35rem);
    line-height: 1.18;
  }

  #introAdvanceButton {
    top: 58%;
    min-width: clamp(188px, 58vw, 260px);
    min-height: 58px;
    font-size: clamp(1.05rem, 4.9vw, 1.2rem);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  #introAdvanceButton.wf-pop {
    transform: translateX(-50%);
  }

  #introAdvanceButton.wf-floating.wf-pop {
    transform: none;
  }
}