:root {
  color-scheme: dark;
  --bg: #0f1115;
  --panel: #171b22;
  --panel-2: #1f2530;
  --text: #f2f4f8;
  --muted: #aab2c0;
  --accent: #4f5868;
  --border: rgba(255, 255, 255, 0.08);
  --shadow: 0 12px 30px rgba(0, 0, 0, 0.35);
  --radius: 24px;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
}

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 24px;
}

#app {
  width: 100%;
  max-width: 520px;
  text-align: center;
}

h1 {
  margin: 0 0 20px;
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

p {
  color: var(--muted);
}

.card {
  width: 100%;
  min-height: 280px;
  background: transparent;
  border: 0;
  box-shadow: none;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  perspective: 1200px;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.card-inner {
  width: 100%;
  height: 100%;
  min-height: 220px;
  position: relative;
  transform-style: preserve-3d;
  -webkit-transform-style: preserve-3d;
  transition: transform 0.5s ease;
}

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

.card-face {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: calc(var(--radius) - 6px);
  padding: 24px;
  overflow: hidden;
}

.card-front {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border);
  transform: rotateY(0deg) translateZ(1px);
}

.card-back {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border);
  transform: rotateY(-180deg) translateZ(1px);
}

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

.word {
  font-size: clamp(2rem, 6vw, 3.5rem);
  font-weight: 700;
  line-height: 1.2;
  word-break: break-word;
}

.translation {
  font-size: clamp(1.5rem, 5vw, 2.8rem);
  font-weight: 700;
  color: var(--accent);
  word-break: break-word;
}

.small {
  margin-top: 16px;
  font-size: 0.95rem;
  color: var(--muted);
}

.button {
  margin-top: 18px;
  padding: 12px 18px;
  border: 0;
  border-radius: 999px;
  background: var(--accent);
  color: white;
  font-weight: 700;
  cursor: pointer;
}

.button:active {
  transform: scale(0.98);
}

.hidden {
  display: none;
}

.completion-screen {
  position: relative;
  min-height: 70vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  overflow: hidden;
  padding: 32px;
}

.completion-screen h1 {
  position: relative;
  z-index: 2;
  margin: 0;
  text-align: center;
}

.confetti-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 1;
}

.confetti-piece {
  position: absolute;
  left: 50%;
  top: 45%;
  border-radius: 3px;
  opacity: 0;
  animation: confetti-explode 1.8s ease-out forwards;
  transform-origin: center;
}

@keyframes confetti-explode {
  0% {
    opacity: 1;
    transform: translate(0, 0) rotate(0deg) scale(1);
  }

  100% {
    opacity: 0;
    transform: translate(var(--dx), var(--dy)) rotate(var(--rot)) scale(0.9);
  }
}

ruby {
  ruby-position: over;
}

rt {
  font-size: 0.32em;
  color: var(--muted);
  font-weight: 500;
}