:root {
  --bg: #f5efe4;
  --bg-soft: #efe4d2;
  --ink: #18222f;
  --ink-soft: #4d5f74;
  --accent: #d6552f;
  --accent-deep: #a83e21;
  --card: rgba(255, 252, 247, 0.82);
  --line: rgba(24, 34, 47, 0.12);
  --ok: #167c53;
  --bad: #c0392b;
  --shadow: 0 16px 40px rgba(24, 34, 47, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Noto Sans KR", sans-serif;
  color: var(--ink);
  background: linear-gradient(165deg, var(--bg) 20%, var(--bg-soft) 100%);
  position: relative;
  overflow-x: hidden;
}

.bg-shape {
  position: fixed;
  border-radius: 999px;
  filter: blur(2px);
  z-index: 0;
  pointer-events: none;
}

.shape-a {
  width: 460px;
  height: 460px;
  background: rgba(214, 85, 47, 0.18);
  top: -150px;
  right: -80px;
}

.shape-b {
  width: 380px;
  height: 380px;
  background: rgba(24, 34, 47, 0.1);
  left: -120px;
  bottom: -100px;
}

.app {
  max-width: 980px;
  margin: 0 auto;
  padding: 32px 20px 60px;
  position: relative;
  z-index: 1;
}

.hero {
  animation: reveal 0.7s ease;
}

.eyebrow {
  font-family: "Space Grotesk", sans-serif;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-deep);
  margin-bottom: 8px;
}

h1 {
  margin: 0;
  font-family: "Space Grotesk", sans-serif;
  font-size: clamp(2rem, 4vw, 3rem);
}

.hero-copy {
  color: var(--ink-soft);
  max-width: 700px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 18px;
}

.stat-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 12px 14px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(4px);
}

.stat-card .label {
  display: block;
  font-size: 0.85rem;
  color: var(--ink-soft);
}

.stat-card strong {
  font-family: "Space Grotesk", sans-serif;
  font-size: 1.3rem;
}

.mode-tabs {
  margin: 24px 0 16px;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.tab,
button {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  border-radius: 12px;
  padding: 10px 14px;
  cursor: pointer;
  font-weight: 600;
  transition: 0.2s ease;
}

.tab:hover,
button:hover {
  transform: translateY(-1px);
}

.tab.active {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}

.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.primary:hover {
  background: var(--accent-deep);
}

.panel {
  display: none;
  animation: reveal 0.35s ease;
}

.panel.active {
  display: block;
}

.card,
.quiz-box,
.review-box {
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 24px;
  background: var(--card);
  box-shadow: var(--shadow);
  backdrop-filter: blur(4px);
}

.hanzi {
  font-family: "Space Grotesk", sans-serif;
  font-size: clamp(2.6rem, 8vw, 4.4rem);
  margin: 0;
}

.pinyin {
  margin: 10px 0 0;
  font-size: 1.1rem;
  color: var(--accent-deep);
  font-weight: 700;
}

.meaning {
  margin: 10px 0 6px;
  font-size: 1.45rem;
  font-weight: 700;
}

.example {
  margin: 0;
  color: var(--ink-soft);
}

.card-actions {
  margin-top: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.quiz-label {
  margin: 0;
  color: var(--ink-soft);
}

#quiz-question {
  margin: 10px 0 14px;
}

.quiz-options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.quiz-options button {
  text-align: left;
}

.quiz-options button.correct {
  border-color: var(--ok);
  background: rgba(22, 124, 83, 0.12);
}

.quiz-options button.wrong {
  border-color: var(--bad);
  background: rgba(192, 57, 43, 0.12);
}

.quiz-result {
  min-height: 24px;
  font-weight: 700;
  margin: 12px 0;
}

.review-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.review-list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.review-list li {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px;
  background: #fff;
}

.review-list .empty {
  color: var(--ink-soft);
}

@media (max-width: 760px) {
  .hero-stats {
    grid-template-columns: 1fr;
  }

  .quiz-options {
    grid-template-columns: 1fr;
  }

  .card,
  .quiz-box,
  .review-box {
    padding: 18px;
  }
}

@keyframes reveal {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}