:root {
  color-scheme: dark;
  font-family: "Inter Variable", Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #080b14;
  color: #e8eaf6;
  --bg: #080b14;
  --surface: #111627;
  --surface-variant: #1a2035;
  --surface-high: #232b45;
  --surface-hover: #161d29;
  --border: #1a2035;
  --border-strong: #2a3444;
  --cyan: #00d4ff;
  --cyan-bright: #00e5ff;
  --cyan-dim: rgb(0 212 255 / 8%);
  --success: #2ed573;
  --error: #ff4757;
  --warning: #ffb142;
  --text: #e8eaf6;
  --text-2: #9ba3bf;
  --text-3: #8494b2;
  --mono: "JetBrains Mono Variable", "Fira Code", Consolas, monospace;
}

* { box-sizing: border-box; }

html, body { min-width: 320px; min-height: 100%; }

body { margin: 0; background: var(--bg); color: var(--text); }

button, a { -webkit-tap-highlight-color: transparent; }

button:focus-visible, a:focus-visible {
  outline: 2px solid var(--warning);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 8px;
  left: 8px;
  transform: translateY(-160%);
  padding: 10px 14px;
  background: white;
  color: var(--bg);
  font-weight: 700;
}
.skip-link:focus { transform: translateY(0); }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.app-shell { min-height: 100vh; display: flex; flex-direction: column; }

.topbar {
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 0 22px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

.exam-selector {
  min-height: 34px;
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 0 12px;
  border: 1px solid rgb(0 212 255 / 38%);
  color: var(--text);
  text-decoration: none;
  font-size: 13px;
  font-weight: 700;
}

.status-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--cyan); }
.vendor-badge { padding: 2px 6px; background: rgb(0 212 255 / 11%); color: var(--cyan-bright); font: 700 10px/1 var(--mono); }
.selector-caret { margin-left: 4px; color: var(--text-3); font-size: 9px; }

.topbar-actions { display: flex; align-items: center; gap: 14px; }
.demo-badge { color: var(--warning); font: 700 10px/1 var(--mono); letter-spacing: 1.5px; }
.full-platform-link { min-height: 44px; display: inline-flex; align-items: center; color: var(--text-2); text-decoration: none; font-size: 12px; }
.full-platform-link:hover { color: var(--cyan); }
.avatar { width: 32px; height: 32px; display: grid; place-items: center; border-radius: 50%; background: var(--surface-variant); color: var(--text-2); font: 600 12px/1 var(--mono); }

.quiz-workspace { flex: 1; min-height: calc(100vh - 50px); display: flex; flex-direction: column; }
.progress-track { height: 3px; background: var(--surface-variant); }
.progress-fill { width: 10%; height: 100%; background: var(--cyan); transition: width 180ms ease; }

.question-toolbar {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 30px;
  border-bottom: 1px solid var(--border);
}

.question-meta, .quiz-tools, .action-left, .action-right { display: flex; align-items: center; gap: 10px; }
.question-count { color: var(--text-3); font: 600 13px/1 var(--mono); letter-spacing: .5px; }
.question-count #question-number { color: var(--text); }
.meta-pill { padding: 5px 8px; border: 1px solid var(--border); color: var(--text-3); font: 600 10px/1 var(--mono); letter-spacing: 1px; text-transform: uppercase; }
.difficulty-pill.medium { color: var(--warning); border-color: rgb(255 177 66 / 26%); background: rgb(255 177 66 / 8%); }
.difficulty-pill.hard { color: var(--error); border-color: rgb(255 71 87 / 26%); background: rgb(255 71 87 / 8%); }
.difficulty-pill.easy { color: var(--success); border-color: rgb(46 213 115 / 26%); background: rgb(46 213 115 / 8%); }
.keyboard-hint { color: var(--text-3); font: 11px/1 var(--mono); }
.icon-button { width: 44px; height: 44px; border: 0; background: transparent; color: var(--text-3); cursor: pointer; font-size: 19px; }
.icon-button[aria-pressed="true"] { color: var(--warning); }

.question-view { flex: 1; padding: 24px 30px 110px; }
.question-panel { padding: 26px 24px; border: 1px solid var(--border); background: var(--surface); }
.question-panel h2 { margin: 0; font-size: clamp(16px, 2vw, 18px); line-height: 1.55; font-weight: 600; }

.answers { display: grid; gap: 10px; margin-top: 20px; }
.answer-button {
  width: 100%;
  min-height: 64px;
  display: grid;
  grid-template-columns: 28px 1fr;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font: 14px/1.5 inherit;
  text-align: left;
  cursor: pointer;
  transition: background-color 100ms ease, border-color 100ms ease;
}
.answer-button:hover:not(:disabled) { background: var(--surface-hover); border-color: var(--border-strong); }
.answer-button[aria-checked="true"] { border-color: var(--cyan); background: var(--cyan-dim); }
.answer-letter { width: 25px; height: 28px; display: grid; place-items: center; background: var(--surface-high); color: var(--text); font: 700 12px/1 var(--mono); }
.answer-button[aria-checked="true"] .answer-letter { background: var(--cyan); color: var(--bg); }
.answer-button.is-correct { border-color: var(--success); background: rgb(46 213 115 / 7%); }
.answer-button.is-correct .answer-letter { background: var(--success); color: var(--bg); }
.answer-button.is-wrong { border-color: var(--error); background: rgb(255 71 87 / 7%); }
.answer-button.is-wrong .answer-letter { background: var(--error); color: white; }
.answer-button:disabled { cursor: default; }

.feedback { margin-top: 20px; padding: 20px 22px; border: 1px solid var(--border-strong); border-left: 3px solid var(--cyan); background: var(--surface); }
.feedback-header { display: flex; gap: 12px; align-items: flex-start; }
.result-icon { width: 24px; height: 24px; display: grid; place-items: center; border: 1px solid currentColor; font: 700 13px/1 var(--mono); }
.result { margin: 0 0 5px; font-weight: 700; }
.result.correct, .result-icon.correct { color: var(--success); }
.result.incorrect, .result-icon.incorrect { color: var(--error); }
.feedback-label, .panel-label { margin: 0; color: var(--text-3); font: 600 10px/1 var(--mono); letter-spacing: 1.5px; }
.explanation { margin: 16px 0 0 36px; color: var(--text-2); font-size: 13px; line-height: 1.72; }

.action-bar {
  position: fixed;
  z-index: 10;
  left: 0;
  right: 0;
  bottom: 0;
  min-height: 70px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 30px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}
.live-score { color: var(--text-3); font: 11px/1 var(--mono); }
.outline-button, .primary-button, .secondary-button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 18px;
  border-radius: 0;
  font: 600 13px/1 inherit;
  text-decoration: none;
  cursor: pointer;
}
.outline-button, .secondary-button { border: 1px solid var(--border-strong); background: transparent; color: var(--text-2); }
.outline-button:hover, .secondary-button:hover { background: var(--surface-hover); color: var(--text); }
.primary-button { border: 1px solid var(--cyan); background: var(--cyan); color: var(--bg); font-weight: 700; }
.primary-button:disabled { border-color: var(--surface-variant); background: var(--surface-variant); color: var(--text-3); opacity: .55; cursor: not-allowed; }

.results-view { flex: 1; width: min(100% - 32px, 640px); margin: 0 auto; padding: 44px 0 120px; text-align: center; }
.score-ring { width: 112px; height: 112px; display: grid; align-content: center; justify-items: center; margin: 0 auto 22px; border: 3px solid var(--cyan); border-radius: 50%; }
.score-ring strong { color: var(--cyan); font: 700 30px/1 var(--mono); }
.score-ring span { margin-top: 7px; color: var(--text-3); font: 600 10px/1 var(--mono); letter-spacing: 1.5px; }
.results-view h2 { margin: 0; font-size: 22px; }
.result-kpis { display: flex; justify-content: center; gap: 34px; margin: 22px 0 30px; }
.result-kpis div { display: grid; gap: 5px; }
.result-kpis strong { color: var(--cyan); font: 700 20px/1 var(--mono); }
.result-kpis span { color: var(--text-3); font-size: 11px; }
.readiness-panel { padding: 18px; border: 1px solid var(--border); border-left: 2px solid var(--cyan); background: var(--surface); text-align: left; }
.readiness-panel strong { display: block; margin: 8px 0; color: var(--cyan); }
.readiness-panel p:last-child { margin: 0; color: var(--text-2); font-size: 13px; line-height: 1.6; }
.result-actions { display: flex; justify-content: center; gap: 10px; margin-top: 24px; }
.button-link { text-decoration: none; }

[hidden] { display: none !important; }

@media (max-width: 760px) {
  .topbar { padding: 0 12px; }
  .full-platform-link, .keyboard-hint { display: none; }
  .exam-selector { padding-inline: 9px; }
  .question-toolbar { min-height: 58px; padding: 8px 14px; }
  .question-meta { gap: 6px; min-width: 0; }
  .meta-pill { max-width: 155px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .question-view { padding: 14px 12px 98px; }
  .question-panel { padding: 20px 16px; }
  .answer-button { min-height: 62px; padding: 12px; }
  .action-bar { min-height: 76px; padding: 10px 12px; }
  .live-score { display: none; }
  .outline-button, .primary-button, .secondary-button { padding-inline: 13px; }
  .explanation { margin-left: 0; }
}

@media (max-width: 470px) {
  .demo-badge { display: none; }
  .topbar-actions { gap: 7px; }
  .avatar { width: 30px; height: 30px; }
  .vendor-badge { display: none; }
  .question-count { font-size: 12px; }
  .meta-pill { max-width: 125px; font-size: 9px; }
  .icon-button { width: 40px; height: 40px; }
  .action-left > .outline-button { display: none; }
  .action-bar { justify-content: flex-end; }
  .action-right { width: 100%; }
  .action-right button { flex: 1; }
  .result-actions { display: grid; }
}