* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #1a1a2e;
  color: #eee;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  text-align: center;
  max-width: 500px;
  padding: 2rem;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
  color: #e94560;
}

#topic-selector {
  margin-bottom: 1.5rem;
}

.topic-checkboxes {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  justify-content: center;
}

.topic-spacer {
  width: 100%;
  height: 0.5rem;
}

.topic-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.35rem 0.75rem;
  border-radius: 20px;
  font-size: 0.85rem;
  cursor: pointer;
  background: #16213e;
  border: 2px solid #333;
  transition: all 0.2s;
  user-select: none;
}

.topic-chip.selected {
  background: #e94560;
  border-color: #e94560;
}

.topic-chip.kids {
  border-color: #f5a623;
}

.topic-chip.kids.selected {
  background: #f5a623;
  border-color: #f5a623;
}

.topic-chip input[type="checkbox"] {
  display: none;
}

#words {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.word-card {
  background: #16213e;
  padding: 0.75rem;
  border-radius: 8px;
  font-size: 1.25rem;
}

#timer {
  font-size: 4rem;
  font-weight: bold;
  color: #e94560;
  margin-bottom: 1.5rem;
}

.controls {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  flex-wrap: wrap;
}

button {
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  background: #e94560;
  color: #fff;
  transition: background 0.2s;
}

button:hover:not(:disabled) {
  background: #c73652;
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.controls-next {
  margin-top: 2rem;
  text-align: center;
}

.btn-next {
  padding: 1.1rem 3rem;
  font-size: 1.35rem;
  font-weight: bold;
  border-radius: 12px;
}