:root {
    --orange: #E84600;
    --orange-light: #FFF0EB;
    --bg: #FFFFFF;
    --surface: #F7F7F5;
    --border: #E8E8E2;
    --text: #1A1A1A;
    --muted: #888880;
    --correct: #059669;
    --correct-bg: #ECFDF5;
    --wrong: #DC2626;
    --wrong-bg: #FEF2F2;
    --partial: #D97706;
    --partial-bg: #FFFBEB;
    --selected: #EBF5FF;
    --selected-border: #3B82F6;
    --missed: #D1FAE5;
  }

  * { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

  body {
    background: var(--bg);
    color: var(--text);
    font-family: 'DM Sans', sans-serif;
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
  }

  .container {
    max-width: 680px;
    margin: 0 auto;
    padding: 0 16px;
  }

  /* HEADER */
  header {
    padding: 20px 0 16px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 28px;
  }

  .header-inner {
    display: flex;
    align-items: center;
    gap: 12px;
  }

  .logo {
    width: 40px;
    height: 40px;
    background: var(--orange);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-family: 'IBM Plex Mono', monospace;
    font-weight: 600;
    font-size: 13px;
    color: white;
    letter-spacing: -0.5px;
  }

  .header-text h1 {
    font-size: 16px;
    font-weight: 700;
    line-height: 1.2;
    color: var(--text);
  }

  .header-text p {
    color: var(--muted);
    font-size: 13px;
    font-weight: 400;
    margin-top: 1px;
  }

  /* SCREEN MANAGEMENT */
  #screen-home, #screen-quiz, #screen-result {
    display: none;
  }
  #screen-home.active, #screen-quiz.active, #screen-result.active {
    display: block;
  }

  /* HOME SCREEN */
  .hero {
    text-align: center;
    padding: 40px 0 32px;
  }

  .hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--orange-light);
    color: var(--orange);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    padding: 5px 12px;
    border-radius: 20px;
    margin-bottom: 20px;
  }

  .hero h2 {
    font-size: clamp(32px, 8vw, 52px);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -1px;
    margin-bottom: 12px;
  }

  .hero h2 span {
    color: var(--orange);
  }

  .hero-desc {
    font-size: 16px;
    font-weight: 400;
    color: var(--muted);
    max-width: 400px;
    margin: 0 auto 32px;
    line-height: 1.6;
  }

  .btn-launch {
    background: var(--orange);
    color: white;
    border: none;
    font-family: 'DM Sans', sans-serif;
    font-size: 16px;
    font-weight: 600;
    padding: 14px 40px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.15s ease;
    display: inline-block;
    min-height: 48px;
  }

  .btn-launch:hover { background: #C73D00; transform: translateY(-1px); }
  .btn-launch:active { transform: scale(0.98); }

  .info-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-top: 48px;
  }

  .info-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 20px 16px;
    text-align: center;
  }

  .info-card .num {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 28px;
    font-weight: 600;
    color: var(--orange);
  }

  .info-card p {
    font-size: 12px;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-top: 4px;
    font-weight: 600;
  }

  /* QUIZ SCREEN */
  .quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    gap: 12px;
  }

  .quiz-meta {
    display: flex;
    align-items: center;
    gap: 10px;
  }

  .q-number {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 13px;
    color: var(--muted);
  }

  .q-number strong {
    color: var(--orange);
    font-size: 15px;
  }

  .q-id {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    color: var(--muted);
    background: var(--surface);
    padding: 3px 7px;
    border-radius: 4px;
    border: 1px solid var(--border);
  }

  .score-live {
    display: flex;
    gap: 10px;
    align-items: center;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 13px;
  }

  .score-live .correct { color: var(--correct); font-weight: 600; }
  .score-live .wrong { color: var(--wrong); font-weight: 600; }

  /* PROGRESS BAR */
  .progress-wrap {
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    margin-bottom: 24px;
    overflow: hidden;
  }

  .progress-fill {
    height: 100%;
    background: var(--orange);
    border-radius: 2px;
    transition: width 0.4s ease;
  }

  /* QUESTION CARD */
  .question-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 14px;
    animation: fadeUp 0.25s ease;
  }

  @keyframes fadeUp {
    from { opacity: 0; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .question-type {
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 1px;
    text-transform: uppercase;
    color: var(--orange);
    margin-bottom: 10px;
  }

  .question-text {
    font-size: 16px;
    font-weight: 500;
    line-height: 1.55;
    white-space: pre-line;
    color: var(--text);
  }

  /* ANSWERS */
  .answers-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 16px;
  }

  .answer-option {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 13px 14px;
    background: var(--bg);
    border: 1.5px solid var(--border);
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.12s ease;
    user-select: none;
    min-height: 48px;
  }

  .answer-option:hover:not(.revealed) {
    border-color: var(--selected-border);
    background: var(--selected);
  }

  .answer-option.selected:not(.revealed) {
    border-color: var(--selected-border);
    background: var(--selected);
  }

  .answer-option.revealed.correct-answer {
    border-color: var(--correct);
    background: var(--correct-bg);
  }

  .answer-option.revealed.wrong-selected {
    border-color: var(--wrong);
    background: var(--wrong-bg);
  }

  .answer-option.revealed.missed-correct {
    border-color: var(--correct);
    background: var(--correct-bg);
    border-style: dashed;
    opacity: 0.85;
  }

  .answer-checkbox {
    width: 20px;
    height: 20px;
    border: 1.5px solid var(--border);
    border-radius: 5px;
    flex-shrink: 0;
    margin-top: 1px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.12s ease;
    background: white;
  }

  .answer-option.selected:not(.revealed) .answer-checkbox {
    background: var(--selected-border);
    border-color: var(--selected-border);
  }

  .answer-option.revealed.correct-answer .answer-checkbox {
    background: var(--correct);
    border-color: var(--correct);
  }

  .answer-option.revealed.wrong-selected .answer-checkbox {
    background: var(--wrong);
    border-color: var(--wrong);
  }

  .checkmark {
    font-size: 11px;
    color: white;
    display: none;
    line-height: 1;
  }

  .answer-option.selected .checkmark,
  .answer-option.revealed .checkmark { display: block; }

  .answer-text {
    font-size: 15px;
    font-weight: 400;
    line-height: 1.45;
    flex: 1;
    color: var(--text);
  }

  .answer-icon {
    margin-left: auto;
    font-size: 16px;
    display: none;
    flex-shrink: 0;
    margin-top: 1px;
  }

  .answer-option.revealed .answer-icon { display: block; }
  .answer-option.revealed.correct-answer .answer-icon { color: var(--correct); }
  .answer-option.revealed.wrong-selected .answer-icon { color: var(--wrong); }
  .answer-option.revealed.missed-correct .answer-icon { color: var(--correct); }

  /* CONTROLS */
  .controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    margin-bottom: 32px;
  }

  .btn-submit {
    background: var(--orange);
    color: white;
    border: none;
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    font-weight: 600;
    padding: 13px 28px;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.12s ease;
    flex: 1;
    min-height: 48px;
  }

  .btn-submit:hover:not(:disabled) { background: #C73D00; }
  .btn-submit:disabled { opacity: 0.35; cursor: not-allowed; }

  .btn-next {
    background: var(--surface);
    color: var(--text);
    border: 1.5px solid var(--border);
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    font-weight: 600;
    padding: 13px 20px;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.12s ease;
    display: none;
    flex: 1;
    min-height: 48px;
    white-space: nowrap;
  }

  .btn-next:hover { border-color: var(--text); background: white; }
  .btn-next.show { display: block; }

  /* FEEDBACK */
  .feedback-box {
    border-radius: 10px;
    padding: 14px 16px;
    margin-bottom: 14px;
    display: none;
    animation: fadeUp 0.2s ease;
    border: 1.5px solid;
  }

  .feedback-box.show { display: block; }
  .feedback-box.all-correct { background: var(--correct-bg); border-color: var(--correct); }
  .feedback-box.partial { background: var(--partial-bg); border-color: var(--partial); }
  .feedback-box.none { background: var(--wrong-bg); border-color: var(--wrong); }

  .feedback-label {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    margin-bottom: 6px;
  }

  .feedback-box.all-correct .feedback-label { color: var(--correct); }
  .feedback-box.partial .feedback-label { color: var(--partial); }
  .feedback-box.none .feedback-label { color: var(--wrong); }

  .feedback-text {
    font-size: 14px;
    line-height: 1.6;
    white-space: pre-line;
    color: var(--text);
  }

  /* RESULT SCREEN */
  .result-hero {
    text-align: center;
    padding: 48px 0 32px;
  }

  .result-score {
    font-family: 'IBM Plex Mono', monospace;
    font-size: clamp(64px, 18vw, 96px);
    font-weight: 600;
    color: var(--orange);
    line-height: 1;
    display: block;
  }

  .result-label {
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 1px;
    text-transform: uppercase;
    color: var(--muted);
    margin-top: 8px;
  }

  .result-mention {
    font-size: 22px;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin: 20px 0 6px;
  }

  .result-subtitle {
    font-size: 15px;
    color: var(--muted);
    margin-bottom: 36px;
  }

  .result-breakdown {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-bottom: 32px;
  }

  .breakdown-item {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px 12px;
    text-align: center;
  }

  .breakdown-num {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 28px;
    font-weight: 600;
  }

  .breakdown-item:nth-child(1) .breakdown-num { color: var(--correct); }
  .breakdown-item:nth-child(2) .breakdown-num { color: var(--wrong); }
  .breakdown-item:nth-child(3) .breakdown-num { color: var(--partial); }

  .breakdown-label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--muted);
    margin-top: 4px;
    font-weight: 600;
  }

  .result-actions {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
  }

  .btn-secondary {
    background: var(--surface);
    color: var(--text);
    border: 1.5px solid var(--border);
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    font-weight: 600;
    padding: 13px 24px;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.12s;
    min-height: 48px;
  }
  .btn-secondary:hover { border-color: var(--text); background: white; }

  /* MOBILE OPTIMIZATIONS */
  @media (max-width: 480px) {
    .container { padding: 0 14px; }
    header { padding: 16px 0 14px; margin-bottom: 20px; }
    .hero { padding: 28px 0 24px; }
    .info-grid { gap: 8px; }
    .info-card { padding: 16px 12px; }
    .info-card .num { font-size: 24px; }
    .question-card { padding: 16px; }
    .question-text { font-size: 15px; }
    .answer-text { font-size: 14px; }
    .answer-option { padding: 12px; gap: 10px; }
    .controls { flex-direction: column; gap: 8px; }
    .btn-submit, .btn-next { width: 100%; text-align: center; }
    .result-actions { flex-direction: column; }
    .result-actions .btn-launch,
    .result-actions .btn-secondary { width: 100%; }
    .quiz-header { flex-wrap: wrap; }
    .result-breakdown { gap: 8px; }
  }

  @media (max-width: 340px) {
    .info-grid { grid-template-columns: 1fr; }
    .result-breakdown { grid-template-columns: 1fr; }
  }