:root {
  --bg: #f8f7f2;
  --surface: #ffffff;
  --text: #102113;
  --muted: #2e4734;
  --primary: #2f6b2f;
  --primary-press: #245724;
  --border: #c7d6c3;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
  line-height: 1.45;
}

.app {
  min-height: 100dvh;
  max-width: 620px;
  margin: 0 auto;
  padding: 20px 16px 28px;
}

.screen {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px 16px;
}

.screen--active {
  display: block;
}

.logo {
  width: min(100%, 260px);
  height: auto;
  display: block;
  margin: 0 auto 18px;
}

h1,
h2 {
  margin: 0 0 10px;
  line-height: 1.25;
}

h1 {
  font-size: 1.45rem;
}

h2 {
  font-size: 1.35rem;
}

.subtitle {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 1.02rem;
}

.intro,
#end-screen p {
  margin: 0 0 20px;
  font-size: 1rem;
}

.footnote {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.progress {
  margin: 0 0 10px;
  color: var(--muted);
  font-weight: 600;
  font-size: 0.95rem;
}

.question {
  margin-bottom: 16px;
}

.answers {
  display: grid;
  gap: 10px;
}

.btn {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 600;
  min-height: 52px;
  padding: 12px 14px;
  cursor: pointer;
  color: var(--text);
  background: #ffffff;
  text-align: left;
}

.btn:focus-visible {
  outline: 3px solid #1f4f1f;
  outline-offset: 2px;
}

.btn:active {
  transform: translateY(1px);
}

.btn--primary {
  margin-top: 8px;
  text-align: center;
  color: #ffffff;
  background: var(--primary);
  border-color: var(--primary);
}

.btn--primary:active {
  background: var(--primary-press);
}

.btn--correct {
  background: #2d6a2d !important;
  color: #ffffff !important;
  border-color: #2d6a2d !important;
}

.btn--wrong {
  background: #c53030 !important;
  color: #ffffff !important;
  border-color: #c53030 !important;
}

.btn:disabled {
  cursor: not-allowed;
  opacity: 0.7;
}

.sender {
  margin-top: 22px;
  font-weight: 700;
}

@media (min-width: 680px) {
  .app {
    padding-top: 28px;
  }

  .screen {
    padding: 24px;
  }

  h1 {
    font-size: 1.65rem;
  }

  h2 {
    font-size: 1.45rem;
  }
}