:root {
  --bg-1: #03112d;
  --bg-2: #07204f;
  --card: rgba(7, 22, 56, 0.92);
  --text: #e8f0ff;
  --muted: #9fb2d9;
  --accent: #2f7dff;
  --accent-2: #1f5fd6;
  --line: rgba(143, 175, 232, 0.25);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at 20% 0%, #0d2f73 0%, var(--bg-1) 46%), linear-gradient(160deg, var(--bg-1), var(--bg-2));
}

.app-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 18px;
}

.card {
  width: min(520px, 100%);
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--card);
  backdrop-filter: blur(8px);
  padding: 22px;
  box-shadow: 0 18px 48px rgba(0, 0, 0, 0.4);
}

.kicker {
  margin: 0;
  color: #78a7ff;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 12px;
}

h1 {
  margin: 8px 0 6px;
  font-size: 30px;
  line-height: 1.1;
}

.subtitle {
  margin: 0 0 20px;
  color: var(--muted);
}

.group {
  margin-bottom: 16px;
}

.group-title {
  display: block;
  color: #c2d3f6;
  font-size: 14px;
  margin-bottom: 8px;
}

.chips {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.chip {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(11, 34, 83, 0.86);
  color: var(--text);
  padding: 10px 14px;
  cursor: pointer;
}

.chip-active {
  border-color: transparent;
  background: linear-gradient(160deg, #3e8dff, #2f70e0);
}

.primary-btn {
  width: 100%;
  margin-top: 4px;
  border: 0;
  border-radius: 14px;
  padding: 13px 16px;
  font-size: 16px;
  font-weight: 600;
  color: white;
  cursor: pointer;
  background: linear-gradient(160deg, var(--accent), var(--accent-2));
}

.secondary-btn {
  width: 100%;
  margin-top: 10px;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 11px 14px;
  font-size: 15px;
  color: var(--text);
  cursor: pointer;
  background: rgba(13, 39, 95, 0.85);
}

.hint {
  margin: 12px 0 0;
  font-size: 12px;
  color: var(--muted);
}

.hidden {
  display: none;
}

.quiz-head {
  font-size: 13px;
  color: #b7c9ee;
  margin-bottom: 8px;
}

.question {
  margin: 0 0 12px;
  font-size: 18px;
  line-height: 1.3;
}

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

.option-btn {
  text-align: left;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(10, 32, 78, 0.88);
  color: var(--text);
  padding: 12px;
  cursor: pointer;
}

.feedback {
  margin-top: 10px;
  padding: 10px 12px;
  border-radius: 10px;
  font-size: 14px;
}

.feedback-ok {
  background: rgba(30, 127, 89, 0.28);
  border: 1px solid rgba(73, 202, 149, 0.35);
}

.feedback-bad {
  background: rgba(141, 55, 55, 0.28);
  border: 1px solid rgba(230, 122, 122, 0.35);
}