/* ── Reset & base ─────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --green:   #58cc02;
  --green-d: #4aaa00;
  --red:     #ff4b4b;
  --red-d:   #e03e3e;
  --blue:    #1cb0f6;
  --blue-d:  #0d9ed9;
  --yellow:  #ffc800;
  --gray-1:  #f7f7f7;
  --gray-2:  #e5e5e5;
  --gray-3:  #afafaf;
  --gray-4:  #777;
  --dark:    #1f1f1f;
  --white:   #ffffff;
  --shadow:  0 4px 0;
  --radius:  16px;
  --font:    'Nunito', system-ui, sans-serif;
}

html, body {
  height: 100%;
  background: var(--gray-1);
  font-family: var(--font);
  color: var(--dark);
  overflow-x: hidden;
}

#app {
  min-height: 100vh;
  max-width: 680px;
  margin: 0 auto;
  padding: 0 0 40px;
}

/* ── Buttons ──────────────────────────────────────────────────────────────── */
button { cursor: pointer; border: none; font-family: var(--font); font-weight: 700; }

.btn-primary {
  background: var(--green);
  color: var(--white);
  padding: 14px 28px;
  border-radius: 12px;
  box-shadow: var(--shadow) var(--green-d);
  font-size: 16px;
  transition: transform .1s, box-shadow .1s;
  display: inline-block;
}
.btn-primary:active { transform: translateY(3px); box-shadow: 0 1px 0 var(--green-d); }

.btn-secondary {
  background: var(--white);
  color: var(--blue);
  border: 2px solid var(--blue);
  padding: 12px 26px;
  border-radius: 12px;
  font-size: 16px;
  transition: background .15s;
}
.btn-secondary:hover { background: #e8f7ff; }

.btn-back {
  background: none;
  color: var(--gray-3);
  font-size: 18px;
  padding: 6px 12px;
  border-radius: 8px;
}
.btn-back:hover { color: var(--dark); background: var(--gray-2); }

.btn-big { width: 100%; max-width: 380px; font-size: 18px; padding: 18px; }

/* ── Home screen ──────────────────────────────────────────────────────────── */
.home-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 24px;
  gap: 24px;
}

.home-hero { text-align: center; }

.flag-badge {
  font-size: 64px;
  margin-bottom: 12px;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,.15));
}

.app-title {
  font-size: 40px;
  font-weight: 900;
  color: var(--dark);
  letter-spacing: -1px;
}

.app-subtitle {
  color: var(--gray-4);
  margin-top: 6px;
  font-size: 16px;
}

.stats-bar {
  display: flex;
  gap: 20px;
  background: var(--white);
  border-radius: var(--radius);
  padding: 18px 28px;
  box-shadow: 0 2px 8px rgba(0,0,0,.07);
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  min-width: 60px;
}
.stat-icon { font-size: 22px; }
.stat-val  { font-size: 24px; font-weight: 900; color: var(--dark); }
.stat-label{ font-size: 12px; color: var(--gray-3); text-transform: uppercase; letter-spacing: .5px; }

/* ── Lesson select ────────────────────────────────────────────────────────── */
.lesson-select-screen { padding: 16px; }

.screen-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
}
.screen-header h2 { font-size: 22px; font-weight: 900; }

.lessons-grid {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.lesson-card {
  display: flex;
  align-items: center;
  gap: 16px;
  background: var(--white);
  border-radius: var(--radius);
  padding: 16px 20px;
  box-shadow: 0 2px 6px rgba(0,0,0,.06);
  cursor: pointer;
  transition: transform .15s, box-shadow .15s;
  border: 2px solid transparent;
}
.lesson-card:hover:not(.locked) { transform: translateY(-2px); box-shadow: 0 6px 16px rgba(0,0,0,.1); }
.lesson-card.done { border-color: var(--green); }
.lesson-card.locked { opacity: .5; cursor: not-allowed; }

.lesson-icon { font-size: 32px; flex-shrink: 0; }

.lesson-info { flex: 1; min-width: 0; }
.lesson-title { font-weight: 800; font-size: 16px; }
.lesson-desc  { color: var(--gray-3); font-size: 13px; margin-top: 2px; }
.lesson-meta  { color: var(--blue); font-size: 12px; margin-top: 4px; font-weight: 700; }

.lesson-prog { width: 60px; }
.prog-bar { background: var(--gray-2); border-radius: 99px; height: 8px; }
.prog-fill { background: var(--green); border-radius: 99px; height: 100%; transition: width .4s; }

/* ── Exercise screen ──────────────────────────────────────────────────────── */
.exercise-screen {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  padding: 0;
}

.ex-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  background: var(--white);
  box-shadow: 0 1px 4px rgba(0,0,0,.06);
  position: sticky;
  top: 0;
  z-index: 10;
}

.ex-progress { flex: 1; }
.ex-prog-bar { background: var(--gray-2); border-radius: 99px; height: 10px; }
.ex-prog-fill { background: var(--green); border-radius: 99px; height: 100%; transition: width .4s; }

.hearts { display: flex; gap: 4px; font-size: 20px; }
.heart.lost { filter: grayscale(1) opacity(.3); }

.exercise-body {
  flex: 1;
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.exercise-prompt { text-align: center; }
.ex-label {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--gray-3);
  font-weight: 700;
  margin-bottom: 20px;
}
.big-word {
  font-size: 44px;
  font-weight: 900;
  color: var(--dark);
  line-height: 1.1;
  margin-bottom: 8px;
}
.word-type-badge {
  display: inline-block;
  background: var(--gray-2);
  color: var(--gray-4);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 99px;
  text-transform: uppercase;
  letter-spacing: .5px;
}

/* ── Conjugation exercise ───────────────────────────────────────────────── */
.conj-verb-display {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin: 20px 0 12px;
}
.conj-infinitive {
  font-size: 36px;
  font-weight: 900;
  color: var(--dark);
}
.conj-arrow {
  font-size: 28px;
  color: var(--gray-3);
}
.conj-pronoun {
  font-size: 28px;
  font-weight: 800;
  color: var(--blue);
  background: #e8f7ff;
  padding: 4px 14px;
  border-radius: 99px;
}
.conj-hint {
  font-size: 17px;
  color: var(--gray-4);
  margin-bottom: 6px;
}
.conj-hint em { font-style: normal; font-weight: 700; color: var(--dark); }
.conj-note {
  font-size: 12px;
  color: var(--gray-3);
  background: var(--gray-1);
  padding: 6px 12px;
  border-radius: 8px;
  margin-top: 8px;
  display: inline-block;
}

/* ── Sentence exercise ──────────────────────────────────────────────────── */
.sentence-prompt {
  font-size: 26px;
  font-weight: 800;
  color: var(--dark);
  line-height: 1.3;
  margin-top: 16px;
  padding: 20px;
  background: var(--gray-1);
  border-radius: 14px;
  border-left: 4px solid var(--blue);
}
.type-textarea {
  resize: vertical;
  min-height: 80px;
  line-height: 1.5;
  font-size: 18px !important;
}
.type-result-sentence {
  font-size: 16px;
  line-height: 1.5;
}

/* Type input */
.type-area { display: flex; flex-direction: column; gap: 12px; }
.type-input {
  border: 2px solid var(--gray-2);
  border-radius: 12px;
  padding: 16px 18px;
  font-size: 20px;
  font-family: var(--font);
  font-weight: 700;
  color: var(--dark);
  outline: none;
  transition: border-color .15s;
}
.type-input:focus { border-color: var(--blue); }

.type-result {
  padding: 16px 20px;
  border-radius: 12px;
  font-size: 18px;
  font-weight: 700;
}
.type-result.correct { background: #d7ffb8; color: var(--green-d); }
.type-result.wrong   { background: #ffd7d7; color: var(--red-d); }

/* Feedback footer */
.ex-footer {
  padding: 0 16px 16px;
  position: sticky;
  bottom: 0;
}
.feedback {
  border-radius: var(--radius);
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: 0 -2px 12px rgba(0,0,0,.08);
}
.feedback-correct { background: #d7ffb8; }
.feedback-wrong   { background: #ffd7d7; }
.feedback-icon { font-size: 32px; }
.feedback-text { flex: 1; font-size: 16px; font-weight: 700; color: var(--dark); }
.feedback-text strong { color: var(--green-d); }
.feedback-wrong .feedback-text strong { color: var(--red-d); }

/* ── Result screen ────────────────────────────────────────────────────────── */
.result-screen { padding: 24px; }

.result-hero {
  text-align: center;
  padding: 40px 20px 32px;
  border-radius: var(--radius);
  margin-bottom: 24px;
}
.result-hero.pass { background: linear-gradient(135deg, #d7ffb8, #a8f55e); }
.result-hero.fail { background: linear-gradient(135deg, #ffe5b4, #ffca6e); }
.result-emoji { font-size: 56px; margin-bottom: 12px; }
.result-hero h2 { font-size: 32px; font-weight: 900; margin-bottom: 8px; }
.result-hero p  { font-size: 18px; color: var(--gray-4); }
.xp-earned { display: inline-block; margin-top: 12px; background: var(--yellow); padding: 6px 18px; border-radius: 99px; font-weight: 800; font-size: 15px; }

.result-table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 24px;
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,.06);
}
.result-table th {
  background: var(--gray-2);
  padding: 12px 16px;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: .5px;
  text-align: left;
}
.result-table td { padding: 10px 16px; font-size: 15px; border-bottom: 1px solid var(--gray-2); }
.result-table tr:last-child td { border-bottom: none; }
.res-ok    { color: var(--green); font-weight: 800; font-size: 18px; }
.res-fail  { color: var(--red);   font-weight: 800; font-size: 18px; }
.res-label { font-size: 14px; color: var(--gray-4); max-width: 240px; }

.result-actions {
  display: flex;
  gap: 12px;
}
.result-actions .btn-primary   { flex: 1; text-align: center; }
.result-actions .btn-secondary { flex: 1; text-align: center; }

/* ── Tab bar ──────────────────────────────────────────────────────────────── */
.tab-bar {
  display: flex;
  gap: 4px;
  margin-bottom: 16px;
  background: var(--gray-2);
  padding: 4px;
  border-radius: 12px;
}
.tab-btn {
  flex: 1;
  background: transparent;
  color: var(--gray-4);
  padding: 10px 8px;
  border-radius: 9px;
  font-size: 13px;
  font-weight: 700;
  transition: background .15s, color .15s;
}
.tab-btn.active { background: var(--white); color: var(--dark); box-shadow: 0 1px 4px rgba(0,0,0,.1); }

/* Lesson card done check */
.done-check {
  color: var(--green);
  font-size: 16px;
  font-weight: 900;
  margin-top: 4px;
  text-align: center;
}

/* ── Vocab browser ────────────────────────────────────────────────────────── */
.vocab-screen { padding: 16px; }

.search-bar { margin-bottom: 12px; }
.search-input {
  width: 100%;
  border: 2px solid var(--gray-2);
  border-radius: 12px;
  padding: 12px 16px;
  font-size: 16px;
  font-family: var(--font);
  outline: none;
  transition: border-color .15s;
}
.search-input:focus { border-color: var(--blue); }

.cat-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}
.cat-btn {
  background: var(--gray-2);
  color: var(--gray-4);
  border-radius: 99px;
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 700;
  transition: background .15s, color .15s;
}
.cat-btn.active { background: var(--blue); color: var(--white); }

.vocab-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,.06);
}
.vocab-table th {
  background: var(--dark);
  color: var(--white);
  padding: 12px 14px;
  font-size: 13px;
  text-align: left;
  text-transform: uppercase;
  letter-spacing: .5px;
}
.vocab-table td { padding: 10px 14px; font-size: 15px; border-bottom: 1px solid var(--gray-2); }
.vocab-table tr:last-child td { border-bottom: none; }
.vocab-table tr:hover td { background: var(--gray-1); }
.vc-ca   { font-weight: 800; color: var(--dark); }
.vc-en   { color: var(--gray-4); }
.vc-cat  { font-size: 12px; text-transform: uppercase; color: var(--blue); font-weight: 700; letter-spacing: .4px; }
.vc-type { font-size: 12px; color: var(--gray-3); }

/* ── Toast notifications ──────────────────────────────────────────────────── */
.toast {
  position: fixed;
  bottom: 80px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--dark);
  color: var(--white);
  padding: 12px 22px;
  border-radius: 99px;
  font-weight: 700;
  opacity: 0;
  transition: opacity .25s, transform .25s;
  z-index: 9999;
  pointer-events: none;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
.toast-success { background: var(--green-d); }
.toast-error   { background: var(--red-d); }

/* ── Responsive ───────────────────────────────────────────────────────────── */
@media (max-width: 420px) {
  .big-word { font-size: 32px; }
  .options-grid { grid-template-columns: 1fr; }
  .stats-bar { gap: 12px; padding: 14px 16px; }
}

/* ── Animations ───────────────────────────────────────────────────────────── */
@keyframes pop {
  0%   { transform: scale(.8); opacity: 0; }
  70%  { transform: scale(1.08); }
  100% { transform: scale(1); opacity: 1; }
}
.big-word { animation: pop .3s ease; }