:root {
  --bg: #fff9ef;
  --accent: #cdb8f0;
  --accent-soft: #e6dcfb;
  --ink: #4a4034;
  --card-shadow: rgba(74, 64, 52, 0.18);
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
}

main {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.app-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1rem 0.75rem;
  text-align: center;
}

.app-logo {
  width: clamp(140px, 30vw, 200px);
  height: auto;
}

.app-title {
  margin: 0;
  font-size: clamp(1.1rem, 4vw, 1.5rem);
  font-weight: 700;
}

.app-description {
  margin: 0;
  max-width: 34rem;
  font-size: 0.9rem;
  line-height: 1.5;
  opacity: 0.8;
}

.view-instruction {
  border: none;
  background: transparent;
  color: var(--ink);
  font-size: 0.9rem;
  font-weight: 600;
  opacity: 0.75;
  padding: 0.4rem 0.8rem;
  cursor: default;
}

.view-instruction.is-clickable {
  cursor: pointer;
  opacity: 1;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.view[hidden] {
  display: none;
}

/* ---------- Scroll ("pack opening") view ---------- */

#scroll-view {
  position: relative;
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.pack-progress {
  flex: 0 0 auto;
  text-align: center;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink);
  opacity: 0.7;
  padding: 0.25rem;
}

.flip-hint {
  flex: 0 0 auto;
  text-align: center;
  font-size: 0.8rem;
  opacity: 0.55;
  padding: 0 0.5rem 0.25rem;
}

.pack-track {
  flex: 1;
  min-height: 0;
  display: flex;
  align-items: center;
  overflow-x: auto;
  overflow-y: hidden;
  scroll-snap-type: x proximity;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.pack-track.is-wheeling {
  scroll-snap-type: none;
  scroll-behavior: auto;
}

.pack-track::-webkit-scrollbar {
  display: none;
}

.card-slide {
  min-width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  scroll-snap-align: center;
  padding: 1rem 1rem max(2rem, calc(env(safe-area-inset-bottom, 0px) + 1.5rem)) 1rem;
  flex-shrink: 0;
}

.card-slide .card-flip-wrapper {
  opacity: 0;
  transform: translateX(40px) scale(0.85);
}

.card-slide.in-view .card-flip-wrapper {
  animation: card-enter 0.5s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

@keyframes card-enter {
  to {
    opacity: 1;
    transform: none;
  }
}

.scroll-hint {
  position: absolute;
  bottom: 0.5rem;
  left: 0;
  right: 0;
  text-align: center;
  font-size: 0.85rem;
  opacity: 0.55;
  pointer-events: none;
  animation: hint-bounce 1.8s ease-in-out infinite;
}

@keyframes hint-bounce {
  0%, 100% { transform: translateX(0); }
  50% { transform: translateX(4px); }
}

/* ---------- Flip card (shared) ---------- */

.card-flip-wrapper {
  height: 100%;
  width: auto;
  max-width: min(440px, 80vw);
  aspect-ratio: 1 / 1;
  perspective: 1200px;
  cursor: pointer;
}

.card-flip-wrapper:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
  border-radius: 20px;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.card-inner.flipped {
  transform: rotateY(180deg);
}

.card-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: 18px;
  overflow: hidden;
  box-shadow: 0 10px 28px var(--card-shadow);
  background: #eee;
}

.card-face img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  -webkit-user-drag: none;
}

.card-back {
  transform: rotateY(180deg);
}

.card-grid .card-flip-wrapper {
  width: 100%;
}

/* ---------- Overview (grid) view ---------- */

#overview-view {
  padding: 0.5rem 1rem 2.5rem;
}

.overview-toggle {
  display: flex;
  justify-content: center;
  gap: 4px;
  background: var(--accent-soft);
  border-radius: 999px;
  padding: 4px;
  max-width: fit-content;
  margin: 0.5rem auto 1.5rem;
}

.toggle-btn {
  border: none;
  background: transparent;
  color: var(--ink);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.55rem 1rem;
  min-height: 44px;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.toggle-btn.active {
  background: var(--accent);
  color: #2f2740;
}

.card-grid[hidden],
.card-grid-all[hidden] {
  display: none;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
  max-width: 1100px;
  margin: 0 auto;
}

.card-grid-all {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
  max-width: 1100px;
  margin: 0 auto;
}

.card-pair-preview {
  display: flex;
  gap: 6px;
  cursor: pointer;
  border-radius: 12px;
}

.card-pair-preview:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
  border-radius: 16px;
}

.pair-face {
  flex: 1;
  aspect-ratio: 1 / 1;
  border-radius: 14px;
  overflow: hidden;
  box-shadow: 0 6px 16px var(--card-shadow);
}

.pair-face img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  -webkit-user-drag: none;
}

/* ---------- Empty state ---------- */

.empty-state {
  text-align: center;
  padding: 3rem 1.5rem;
  opacity: 0.7;
  font-size: 0.95rem;
  max-width: 32rem;
  margin: 0 auto;
}