:root {
  --brown-900: #3d2b12;
  --brown-700: #5a4423;
  --brown-500: #8a6d3b;
  --brown-300: #c9b896;
  --brown-100: #f3ede1;
  --cream: #fdfcf9;
  --ok: #2e7d4f;
  --ok-bg: #e7f5ec;
  --bad: #b3402a;
  --bad-bg: #fbeae6;
  --shadow: 0 1px 3px rgba(61, 43, 18, 0.12);
  font-size: 16px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--brown-100);
  color: var(--brown-900);
  line-height: 1.5;
}

.topbar {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: .8rem 1.5rem;
  background: var(--brown-900);
  color: var(--cream);
  flex-wrap: wrap;
}
.topbar__brand { font-weight: 700; font-size: 1.2rem; letter-spacing: .02em; }
.topbar__brand span { color: var(--brown-300); }
.topbar__lessons { display: flex; gap: .4rem; flex-wrap: wrap; }
.topbar__lessons button {
  background: transparent; border: 1px solid var(--brown-500); color: var(--cream);
  border-radius: 999px; padding: .3rem .9rem; cursor: pointer; font-size: .85rem;
}
.topbar__lessons button.active { background: var(--brown-500); border-color: var(--brown-500); }
.topbar__lessons button.done::after { content: " ✓"; }

.app { max-width: 880px; margin: 0 auto; padding: 1.5rem 1rem 4rem; }
.loading { text-align: center; padding: 3rem; color: var(--brown-500); }

.lesson-header h1 { margin: 0 0 .1rem; font-size: 1.6rem; color: var(--brown-700); }
.lesson-header .subtitle { color: var(--brown-500); margin: 0 0 .3rem; }
.lesson-header .topics { font-style: italic; color: #555; font-size: .95rem; }
.phon { color: var(--brown-500); font-style: italic; }

.steps-nav {
  display: flex; gap: .3rem; overflow-x: auto; padding: .8rem 0 1.2rem;
  border-bottom: 1px solid var(--brown-300); margin-bottom: 1.2rem;
}
.steps-nav button {
  flex: none; border: none; background: var(--cream); color: var(--brown-700);
  padding: .4rem .8rem; border-radius: 8px; cursor: pointer; font-size: .82rem;
  box-shadow: var(--shadow); white-space: nowrap;
}
.steps-nav button.active { background: var(--brown-700); color: var(--cream); }
.steps-nav button.visited:not(.active) { border-bottom: 2px solid var(--ok); }

.card {
  background: var(--cream); border-radius: 12px; padding: 1.2rem 1.4rem;
  box-shadow: var(--shadow); margin-bottom: 1rem;
}
.card h2 { margin-top: 0; color: var(--brown-700); font-size: 1.15rem; }
.card h3 { color: var(--brown-700); font-size: 1rem; margin-bottom: .3rem; }
.note { color: #666; font-size: .9rem; }

table.data { border-collapse: collapse; width: 100%; margin: .5rem 0; }
table.data td, table.data th { border-bottom: 1px solid var(--brown-100); padding: .35rem .5rem; text-align: left; vertical-align: top; }
table.data th { color: var(--brown-500); font-weight: 600; font-size: .85rem; }
.label-cell { color: var(--brown-500); font-weight: 600; white-space: nowrap; }

.vocab-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: .4rem; }
.vocab-grid .word { padding: .4rem .5rem; border-radius: 8px; background: var(--brown-100); font-size: .92rem; }
.vocab-grid .word b { color: var(--brown-700); }

/* flashcards */
.flashcard-wrap { display: flex; flex-direction: column; align-items: center; gap: 1rem; }
.flashcard {
  width: 100%; max-width: 420px; min-height: 140px; border-radius: 14px;
  background: linear-gradient(160deg, var(--brown-700), var(--brown-900)); color: var(--cream);
  display: flex; align-items: center; justify-content: center; text-align: center;
  padding: 1.5rem; cursor: pointer; font-size: 1.3rem; box-shadow: 0 4px 14px rgba(61,43,18,.25);
  user-select: none;
}
.flashcard .phon { color: var(--brown-300); display: block; margin-top: .3rem; font-size: 1rem; }
.flashcard-controls { display: flex; gap: .5rem; align-items: center; flex-wrap: wrap; justify-content: center; }
.flashcard-progress { color: var(--brown-500); font-size: .85rem; }

button.btn {
  background: var(--brown-700); color: var(--cream); border: none; border-radius: 8px;
  padding: .5rem 1.1rem; cursor: pointer; font-size: .9rem;
}
button.btn.secondary { background: var(--brown-100); color: var(--brown-700); }
button.btn.ghost { background: transparent; color: var(--brown-700); border: 1px solid var(--brown-300); }
button.btn.ok { background: var(--ok); }
button.btn.bad { background: var(--bad); }
button.btn:disabled { opacity: .5; cursor: default; }

/* drills / test */
.drill-item, .test-item { border-bottom: 1px dashed var(--brown-300); padding: .8rem 0; }
.drill-item:last-child, .test-item:last-child { border-bottom: none; }
.drill-cz { font-weight: 600; margin-bottom: .4rem; }
.drill-answer-row { display: flex; gap: .5rem; flex-wrap: wrap; align-items: center; }
.drill-answer-row input[type=text] {
  flex: 1; min-width: 200px; padding: .45rem .6rem; border: 1px solid var(--brown-300);
  border-radius: 8px; font-size: .95rem;
}
.reveal-box {
  margin-top: .5rem; padding: .5rem .7rem; border-radius: 8px; background: var(--brown-100);
  display: none;
}
.reveal-box.show { display: block; }
.verdict { font-weight: 600; margin-top: .4rem; }
.verdict.correct { color: var(--ok); }
.verdict.wrong { color: var(--bad); }

.score-summary {
  text-align: center; padding: 1.5rem; border-radius: 12px; margin-top: 1rem;
}
.score-summary .points { font-size: 2.4rem; font-weight: 700; color: var(--brown-700); }
.score-summary .grade { font-size: 1.1rem; margin-top: .3rem; }
.history { margin-top: 1rem; font-size: .85rem; color: #666; }
.history table { width: 100%; }

.dialogue-line { display: grid; grid-template-columns: 70px 1fr; gap: .6rem; margin-bottom: .6rem; align-items: start; }
.dialogue-line .speaker { color: var(--brown-500); font-weight: 700; font-size: .85rem; }
.dialogue-line .cz { color: #444; }
.dialogue-line .en { color: var(--brown-700); font-weight: 600; }

.step-footer { display: flex; justify-content: space-between; margin-top: 1.5rem; }

@media (max-width: 600px) {
  table.data { font-size: .85rem; }
  .app { padding: 1rem .6rem 3rem; }
}