* {
  box-sizing: border-box;
}

:root {
  --bg: #f4f4f5;
  --card: #ffffff;
  --text: #18181b;
  --muted: #71717a;
  --border: #d4d4d8;
  --accent: #2563eb;
  --error: #dc2626;
}

html, body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.5;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
  padding: 24px 16px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  width: 100%;
  max-width: 460px;
  padding: 24px;
  margin-top: 8vh;
}

h1 {
  font-size: 1.6rem;
  margin: 0 0 8px;
}

h2 {
  font-size: 1.3rem;
  margin: 0 0 16px;
  min-height: 2.6em;
}

label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin: 16px 0 6px;
}

input[type="text"] {
  width: 100%;
  padding: 12px 14px;
  font-size: 17px; /* >=16px avoids iOS zoom-on-focus */
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  color: var(--text);
}

input[type="text"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: 0;
  border-color: var(--accent);
}

button {
  width: 100%;
  margin-top: 16px;
  padding: 13px;
  font-size: 17px;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

button:active {
  opacity: 0.85;
}

button:disabled {
  opacity: 0.5;
  cursor: default;
}

.muted {
  color: var(--muted);
  font-size: 0.95rem;
}

.error {
  color: var(--error);
  font-size: 0.9rem;
  margin-top: 10px;
}

.quiz-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.timer {
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: 1.1rem;
}

.timer.low {
  color: var(--error);
}

#answer-form {
  display: block;
}