:root {
  --ink: #363648;
  --muted: #828299;
  --quiet: #a6a1ad;
  --paper: rgba(255, 255, 255, 0.62);
  --paper-strong: rgba(255, 255, 255, 0.82);
  --line: rgba(255, 255, 255, 0.72);
  --orange: #ff9f1c;
  --orange-dark: #e88300;
  --green: #62b977;
  --red: #d96b65;
  --shadow: 0 28px 80px rgba(72, 61, 53, 0.16);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100dvh;
  color: var(--ink);
  font-family: ui-rounded, "SF Pro Rounded", "Nunito", "Avenir Next Rounded", system-ui, sans-serif;
  background:
    radial-gradient(circle at 15% 12%, rgba(255, 179, 71, 0.34), transparent 26rem),
    radial-gradient(circle at 86% 18%, rgba(255, 210, 224, 0.56), transparent 24rem),
    radial-gradient(circle at 50% 95%, rgba(192, 226, 200, 0.42), transparent 22rem),
    linear-gradient(135deg, #fbf7f2, #f1eef1 56%, #fff6ec);
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: -20%;
  pointer-events: none;
  background:
    linear-gradient(120deg, transparent 10%, rgba(255,255,255,0.38) 25%, transparent 42%),
    radial-gradient(circle at 70% 35%, rgba(255,255,255,0.35), transparent 18rem);
  filter: blur(18px);
  animation: drift 18s ease-in-out infinite alternate;
}

@keyframes drift {
  from { transform: translate3d(-2%, -1%, 0) rotate(-1deg); }
  to { transform: translate3d(2%, 1%, 0) rotate(1deg); }
}

.app-shell {
  position: relative;
  z-index: 1;
  width: min(100%, 620px);
  min-height: 100dvh;
  margin: 0 auto;
  padding: max(18px, env(safe-area-inset-top)) 20px max(24px, env(safe-area-inset-bottom));
}

.hero {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
  padding-top: 10px;
}

.eyebrow, .label {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.22em;
  color: var(--orange-dark);
  font-size: 12px;
  font-weight: 900;
}

h1 {
  margin: 4px 0 0;
  font-size: clamp(34px, 8vw, 52px);
  line-height: 0.95;
  letter-spacing: -0.055em;
}

.subtitle {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 15px;
  font-weight: 760;
}

button {
  border: 0;
  color: var(--ink);
  font: inherit;
  font-weight: 850;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.ghost-button, .control-button, .audio-chip, .scope-button {
  border: 1px solid var(--line);
  background: var(--paper-strong);
  box-shadow: 0 14px 36px rgba(95, 78, 62, 0.08), inset 0 1px 0 rgba(255,255,255,0.82);
  backdrop-filter: blur(18px);
}

.ghost-button {
  padding: 14px 18px;
  border-radius: 24px;
  white-space: nowrap;
}

.scope-bar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin: 22px 0 16px;
}

.scope-button {
  min-height: 58px;
  border-radius: 28px;
  font-size: 16px;
}

.scope-button.is-active,
.primary-button,
.rating-button.good,
.rating-button.easy {
  color: white;
  background: linear-gradient(180deg, #ffb74a, #ff9619);
  box-shadow: 0 18px 42px rgba(255, 145, 18, 0.28), inset 0 1px 0 rgba(255,255,255,0.35);
}

.status-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 18px 22px;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: var(--paper);
  box-shadow: var(--shadow), inset 0 1px 0 rgba(255,255,255,0.78);
  backdrop-filter: blur(22px);
}

.status-panel h2 {
  margin: 4px 0 0;
  font-size: 24px;
  letter-spacing: -0.03em;
}

.status-meta {
  display: flex;
  gap: 6px;
  color: var(--muted);
  font-weight: 800;
  white-space: nowrap;
}

.card {
  position: relative;
  min-height: 54dvh;
  margin: 18px 0;
  border-radius: 36px;
  transform-style: preserve-3d;
  transition: transform 520ms cubic-bezier(.2,.8,.2,1);
}

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

.card-face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 36px;
  background:
    linear-gradient(145deg, rgba(255,255,255,0.88), rgba(255,251,244,0.62)),
    radial-gradient(circle at 80% 5%, rgba(255, 165, 32, 0.14), transparent 18rem);
  box-shadow: var(--shadow), inset 0 1px 0 rgba(255,255,255,0.9);
  backface-visibility: hidden;
  backdrop-filter: blur(28px);
  overflow: hidden;
}

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

.chip-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.chip, .article {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 0 14px;
  border-radius: 18px;
  color: var(--orange-dark);
  background: rgba(255, 152, 24, 0.10);
  font-size: 12px;
  font-weight: 950;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.chip-soft {
  color: var(--muted);
  background: rgba(126, 125, 145, 0.10);
}

.audio-chip {
  margin-left: auto;
  min-height: 42px;
  padding: 0 16px;
  border-radius: 22px;
}

.audio-chip.is-loading { opacity: 0.58; }
.audio-chip.is-playing { color: var(--orange-dark); }

.front-content, .back-content {
  margin: auto 0;
}

.article-line {
  display: grid;
  gap: 8px;
}

.article:empty { display: none; }

.front-content h3,
.back-content h3 {
  margin: 8px 0 0;
  font-size: clamp(44px, 12vw, 74px);
  line-height: 0.94;
  letter-spacing: -0.06em;
}

.hint, .corner-hint {
  color: var(--quiet);
  font-weight: 800;
}

.corner-hint {
  margin: auto 0 0 auto;
}

.example {
  display: grid;
  gap: 8px;
  margin-top: 22px;
  padding: 18px;
  border-radius: 24px;
  background: rgba(255,255,255,0.66);
  border: 1px solid var(--line);
}

.example p {
  margin: 0;
  font-size: 18px;
  font-weight: 820;
  line-height: 1.25;
}

.example p + p {
  color: var(--muted);
}

.controls {
  display: grid;
  grid-template-columns: 1fr 1.3fr 1fr;
  gap: 10px;
  margin-top: 10px;
}

.control-button, .primary-button {
  min-height: 64px;
  border-radius: 30px;
  font-size: 19px;
}

.rating-row {
  display: none;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-top: 12px;
}

.rating-button {
  min-height: 52px;
  border-radius: 24px;
  background: var(--paper-strong);
  border: 1px solid var(--line);
}

.rating-button.again { color: var(--red); }
.rating-button.hard { color: #a6813a; }

@media (max-width: 420px) {
  .app-shell { padding-inline: 14px; }
  .card-face { padding: 24px; }
  .front-content h3, .back-content h3 { font-size: clamp(40px, 13vw, 56px); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation: none !important;
    transition-duration: 0.01ms !important;
  }
}