:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --surface-soft: #fbfcfd;
  --ink: #15202b;
  --muted: #5e6a77;
  --line: #dde3ea;
  --accent: #1e5ea8;
  --accent-soft: #edf3fb;
  --danger: #b7483b;
  --success: #2e8a61;
  --radius-md: 12px;
  --radius-lg: 16px;
  --shadow-soft: 0 10px 30px rgba(16, 30, 54, 0.06);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Public Sans", "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
}

.site-shell {
  width: min(920px, 92vw);
  margin: 0 auto;
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  padding: 0.8rem 0;
}

.brand {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
}

.main-nav {
  display: flex;
  gap: 0.5rem;
}

.view-btn {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface-soft);
  color: var(--ink);
  padding: 0.45rem 0.8rem;
  font-size: 0.88rem;
  font-weight: 600;
}

.view-btn:hover {
  background: #f0f4f8;
}

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

.app {
  width: min(920px, 92vw);
  margin: 1.6rem auto 2.2rem;
  padding: 1.35rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
}

.hero h1 {
  margin: 0;
  font-family: "Public Sans", "Segoe UI", sans-serif;
  line-height: 1.2;
}

.hero-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.8rem;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 0.55rem;
}

.language-toggle {
  display: inline-flex;
  gap: 0.35rem;
}

.language-btn {
  padding: 0.45rem 0.62rem;
  font-size: 0.82rem;
}

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

.language-btn.is-active:hover {
  background: var(--ink);
  border-color: var(--ink);
  color: #fff;
}

.hero h1 {
  font-size: clamp(1.6rem, 3.2vw, 2.1rem);
  letter-spacing: -0.02em;
}

.eyebrow {
  margin: 0 0 0.35rem;
  display: inline-block;
  padding: 0.22rem 0.55rem;
  border-radius: 999px;
  background: var(--accent-soft);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
  font-size: 0.72rem;
  color: var(--accent);
}

.subtitle {
  margin: 0.55rem 0 0;
  color: var(--muted);
  max-width: 68ch;
  line-height: 1.45;
}

.focus-toggle {
  white-space: nowrap;
}

.study-view {
  display: none;
}

.study-view.is-active {
  display: block;
}

.controls,
.vocab-controls,
.card-actions,
.rating-actions {
  display: grid;
  gap: 0.65rem;
}

.controls,
.vocab-controls {
  margin-top: 1.2rem;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
}

label {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--muted);
}

input,
select,
textarea,
button {
  font: inherit;
}

input,
select,
textarea {
  padding: 0.62rem 0.68rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: var(--surface-soft);
  color: var(--ink);
}

input:focus,
select:focus,
textarea:focus,
button:focus-visible,
.card:focus-visible {
  outline: 2px solid rgba(30, 94, 168, 0.28);
  outline-offset: 1px;
}

textarea {
  resize: vertical;
  min-height: 90px;
}

button {
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  padding: 0.62rem 0.85rem;
  cursor: pointer;
  font-weight: 600;
  background: var(--accent);
  color: #fff;
  transition: background-color 150ms ease, border-color 150ms ease;
}

button:hover {
  background: #1a5393;
}

button.ghost {
  background: var(--surface-soft);
  color: var(--ink);
  border: 1px solid var(--line);
}

button.ghost:hover {
  background: #f3f6fa;
}

button.danger {
  background: var(--danger);
}

button.success {
  background: var(--success);
}

.status {
  margin: 1rem 0 0.9rem;
  padding: 0.75rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--surface-soft);
}

.status p {
  margin: 0.35rem 0;
  font-size: 0.92rem;
}

.progress-wrap {
  height: 8px;
  background: #e8eef5;
  border-radius: 999px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #1f8a77, #2f7aa4);
  transition: width 200ms ease;
}

.card-panel {
  margin-top: 0.7rem;
  perspective: 1200px;
}

.card {
  position: relative;
  min-height: 240px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
  background: var(--surface);
  transform-style: preserve-3d;
  transition: transform 380ms ease;
  cursor: pointer;
}

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

.card-face {
  position: absolute;
  inset: 0;
  padding: 1.3rem;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  transform-style: preserve-3d;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.7rem;
}

.card-front {
  transform: rotateY(0deg);
  z-index: 2;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.meta-pill {
  border-radius: 999px;
  border: 1px solid var(--line);
  padding: 0.18rem 0.5rem;
  font-size: 0.74rem;
  font-weight: 700;
  color: var(--muted);
  background: var(--surface-soft);
}

.meta-pill.is-priority {
  border-color: #f0c56e;
  background: #fff7e2;
  color: #8b5a00;
}

.memory-cue {
  margin: 0;
  color: var(--accent);
  font-size: 0.92rem;
  font-weight: 700;
}

.card-front h2 {
  margin: 0;
  font-size: clamp(1.3rem, 2.5vw, 1.8rem);
  line-height: 1.3;
}

.hint {
  margin-top: auto;
  color: var(--muted);
  font-size: 0.84rem;
}

.card-back {
  transform: rotateY(180deg);
  z-index: 1;
}

.example {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

.ged-trap {
  margin: 0.6rem 0 0;
  padding: 0.5rem 0.6rem;
  border-radius: 10px;
  background: #fff4f2;
  border: 1px solid #f5d2cb;
  color: #8b2f23;
  font-size: 0.86rem;
  line-height: 1.35;
  font-weight: 600;
}

.card-actions,
.rating-actions {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 0.7rem;
}

.rating-actions {
  grid-template-columns: 1fr 1fr;
}

.vocab-list {
  margin-top: 0.75rem;
}

#vocabList {
  display: grid;
  gap: 0.6rem;
}

.vocab-item {
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 0.75rem 0.8rem;
  background: var(--surface-soft);
}

.vocab-item h3 {
  margin: 0;
  font-size: 1rem;
}

.vocab-header {
  display: flex;
  justify-content: space-between;
  gap: 0.6rem;
  align-items: center;
}

.vocab-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.vocab-memory {
  margin: 0.35rem 0 0;
  color: var(--accent);
  font-size: 0.86rem;
  font-weight: 700;
}

.vocab-meta {
  margin: 0.3rem 0 0;
  color: var(--muted);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.vocab-definition {
  margin: 0.45rem 0 0;
  line-height: 1.45;
}

.site-footer {
  width: min(920px, 92vw);
  margin: 0 auto 1.6rem;
  color: var(--muted);
  font-size: 0.85rem;
}

body.focus-mode .subtitle,
body.focus-mode .objectives,
body.focus-mode #flashcardsView .controls,
body.focus-mode #flashcardsView .status {
  display: none;
}

body.focus-mode .app {
  width: min(760px, 94vw);
}

body.focus-mode .hero {
  margin-bottom: 0.9rem;
}

body.focus-mode .hero h1 {
  font-size: clamp(1.35rem, 2.7vw, 1.7rem);
}

body.focus-mode #flashcardsView .card {
  min-height: 280px;
}

@media (max-width: 640px) {
  .app {
    margin-top: 1rem;
    padding: 0.95rem;
  }

  .hero-row {
    flex-direction: column;
    align-items: stretch;
  }

  .hero-actions {
    width: 100%;
    flex-direction: column;
    align-items: stretch;
  }

  .language-toggle {
    width: 100%;
  }

  .language-btn {
    flex: 1;
  }

  .objectives {
    grid-template-columns: 1fr;
  }

  .main-nav {
    width: 100%;
  }

  .view-btn {
    flex: 1;
  }

  .nav-wrap {
    flex-direction: column;
    align-items: flex-start;
  }

  .focus-toggle {
    width: 100%;
  }

  .card {
    min-height: 250px;
  }

  .card-actions,
  .rating-actions {
    grid-template-columns: 1fr;
  }
}