:root {
  color-scheme: dark;
  --vh: 1vh;
  --color-bg: radial-gradient(circle at 20% 20%, #2f1747 0%, #0c0713 60%);
  --color-surface: rgba(28, 19, 40, 0.9);
  --color-accent: #b890ff;
  --color-accent-strong: #e0b8ff;
  --color-text: #f5f1ff;
  --color-text-muted: rgba(245, 241, 255, 0.72);
  --color-warning: #f8c77d;
  --card-shadow: 0 18px 45px rgba(12, 3, 33, 0.35);
  --font-sans: 'Noto Sans JP', 'Hiragino Kaku Gothic ProN', 'Yu Gothic', sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: calc(var(--vh) * 100);
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.app-header,
.app-footer {
  text-align: center;
  padding: 1.5rem 1rem;
  width: min(720px, 100%);
  margin: 0 auto;
}

.app-header__title {
  margin: 0 0 0.5rem;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  letter-spacing: 0.08em;
}

.app-header__subtitle {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 1rem;
  line-height: 1.6;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: radial-gradient(circle at 20% 20%, rgba(185, 144, 255, 0.15), transparent 55%),
    radial-gradient(circle at 80% 30%, rgba(116, 202, 255, 0.12), transparent 60%);
  pointer-events: none;
  z-index: -1;
}

.app-layout {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  width: min(720px, 100%);
  margin: 0 auto;
}

.card-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  width: min(420px, 90vw);
}

.card-stage__hint {
  margin: 0;
  font-size: 0.95rem;
  letter-spacing: 0.08em;
  color: rgba(232, 210, 255, 0.68);
  text-align: center;
}

.app-footer {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}