:root{
  --blue: #1a56db;
  --blue-dark: #12409e;
  --blue-light: #eaf1ff;
  --green: #16a34a;
  --red: #dc2626;
  --amber: #d97706;
  --ink: #1a1f2b;
  --ink-soft: #5b6472;
  --border: #e2e6ee;
  --bg: #f4f6fb;
  --card: #ffffff;
  --radius: 14px;
  --shadow: 0 2px 10px rgba(20,30,60,.06), 0 1px 2px rgba(20,30,60,.04);
}

*{ box-sizing:border-box; }
html,body{ height:100%; }
body{
  margin:0;
  background:var(--bg);
  color:var(--ink);
  font-family:'Noto Sans Sinhala','Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
  -webkit-font-smoothing:antialiased;
}

.screen{ display:none; min-height:100vh; }
.screen.active{ display:block; }

/* ============ SETUP SCREEN ============ */
#setup-screen.active{
  display:flex; align-items:center; justify-content:center;
  padding:32px 16px;
}
.setup-card{
  background:var(--card);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  padding:36px;
  width:100%;
  max-width:560px;
}
.brand{ text-align:center; margin-bottom:24px; }
.brand-badge{ font-size:40px; margin-bottom:6px; }
.brand h1{ font-size:22px; margin:0 0 4px; color:var(--blue-dark); }
.subtitle{ margin:0; color:var(--ink-soft); font-size:14px; }

.notice{
  background:#fff7e6;
  border:1px solid #f5d78e;
  color:#8a5a00;
  border-radius:10px;
  padding:12px 14px;
  font-size:13px;
  line-height:1.5;
  margin-bottom:24px;
}
.notice code{ background:#fff0cc; padding:1px 5px; border-radius:4px; }

.field-group{ margin-bottom:22px; }
.field-group > label{ display:block; font-weight:600; margin-bottom:8px; font-size:14px; }
.field-group small{ display:block; color:var(--ink-soft); font-size:12px; margin-top:6px; }

#timeInput{
  width:100%;
  padding:12px 14px;
  border:1.5px solid var(--border);
  border-radius:10px;
  font-size:15px;
  font-family:inherit;
}
#timeInput:focus{ outline:none; border-color:var(--blue); }

.mode-options{ display:grid; grid-template-columns:1fr 1fr; gap:12px; }
.mode-card{ position:relative; display:block; cursor:pointer; }
.mode-card input{ position:absolute; opacity:0; }
.mode-card-inner{
  border:1.5px solid var(--border);
  border-radius:12px;
  padding:14px;
  transition:.15s;
  display:flex; flex-direction:column; gap:4px;
}
.mode-card input:checked + .mode-card-inner{
  border-color:var(--blue);
  background:var(--blue-light);
}
.mode-title{ font-weight:600; font-size:14px; }
.mode-desc{ font-size:12px; color:var(--ink-soft); }

.btn-primary{
  width:100%;
  background:var(--blue);
  color:#fff;
  border:none;
  padding:14px;
  border-radius:10px;
  font-size:15px;
  font-weight:600;
  cursor:pointer;
  transition:.15s;
  font-family:inherit;
}
.btn-primary:hover{ background:var(--blue-dark); }

/* ============ EXAM SCREEN ============ */
.exam-header{
  background:var(--card);
  border-bottom:1px solid var(--border);
  padding:12px 20px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  position:sticky; top:0; z-index:10;
}
.exam-header-left{ display:flex; flex-direction:column; }
.exam-title{ font-weight:700; font-size:15px; color:var(--blue-dark); }
.exam-progress{ font-size:12px; color:var(--ink-soft); }
.exam-header-right{ display:flex; align-items:center; gap:14px; }

.timer-box{
  display:flex; align-items:center; gap:6px;
  background:var(--blue-light);
  color:var(--blue-dark);
  padding:8px 14px;
  border-radius:10px;
  font-weight:700;
  font-variant-numeric:tabular-nums;
  font-size:15px;
}
.timer-box.warn{ background:#fde8e8; color:var(--red); }

.btn-submit{
  background:var(--green);
  color:#fff;
  border:none;
  padding:10px 20px;
  border-radius:9px;
  font-weight:600;
  cursor:pointer;
  font-family:inherit;
  font-size:14px;
}
.btn-submit:hover{ opacity:.9; }

.exam-body{
  display:flex;
  max-width:1100px;
  margin:0 auto;
  padding:20px 16px 60px;
  gap:20px;
  align-items:flex-start;
}

.question-nav{
  width:220px;
  flex-shrink:0;
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:14px;
  display:grid;
  grid-template-columns:repeat(5,1fr);
  gap:6px;
  position:sticky;
  top:76px;
  max-height:calc(100vh - 100px);
  overflow-y:auto;
}
.nav-dot{
  aspect-ratio:1;
  border-radius:7px;
  border:1.5px solid var(--border);
  background:#fff;
  font-size:11px;
  font-weight:600;
  color:var(--ink-soft);
  cursor:pointer;
  display:flex; align-items:center; justify-content:center;
}
.nav-dot.answered{ background:#e7f7ed; border-color:var(--green); color:var(--green); }
.nav-dot.current{ background:var(--blue); border-color:var(--blue); color:#fff; }

.question-panel{ flex:1; min-width:0; }
.question-card{
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:26px;
  box-shadow:var(--shadow);
}
.question-number{
  display:inline-block;
  background:var(--blue-light);
  color:var(--blue-dark);
  font-weight:700;
  font-size:12px;
  padding:4px 10px;
  border-radius:20px;
  margin-bottom:12px;
}
.question-text{
  font-size:17px;
  line-height:1.6;
  font-weight:500;
  margin-bottom:16px;
}
.question-image-wrap{
  display:flex;
  justify-content:center;
  margin-bottom:20px;
  background:#fafbfd;
  border:1px solid var(--border);
  border-radius:10px;
  padding:16px;
}
.question-image-wrap img{ max-width:220px; max-height:220px; object-fit:contain; }

.options-list{ display:flex; flex-direction:column; gap:10px; }
.option-item{
  display:flex; align-items:center; gap:12px;
  border:1.5px solid var(--border);
  border-radius:10px;
  padding:13px 15px;
  cursor:pointer;
  transition:.12s;
}
.option-item:hover{ border-color:#a9c3f5; background:#fafcff; }
.option-item.selected{ border-color:var(--blue); background:var(--blue-light); }
.option-badge{
  width:26px; height:26px; border-radius:50%;
  border:1.5px solid var(--border);
  display:flex; align-items:center; justify-content:center;
  font-size:12px; font-weight:700; color:var(--ink-soft);
  flex-shrink:0;
  background:#fff;
}
.option-item.selected .option-badge{ background:var(--blue); border-color:var(--blue); color:#fff; }
.option-text{ font-size:14.5px; line-height:1.5; }

.nav-buttons{
  display:flex; justify-content:space-between; align-items:center;
  margin-top:18px;
}
.btn-secondary{
  background:#fff;
  border:1.5px solid var(--border);
  padding:11px 20px;
  border-radius:9px;
  font-weight:600;
  cursor:pointer;
  font-family:inherit;
  font-size:14px;
}
.btn-secondary:hover{ border-color:var(--blue); color:var(--blue); }
.btn-secondary:disabled{ opacity:.4; cursor:not-allowed; }
.btn-ghost{
  background:none;
  border:none;
  color:var(--ink-soft);
  font-weight:600;
  cursor:pointer;
  font-family:inherit;
  font-size:13px;
  text-decoration:underline;
}

/* ============ RESULT SCREEN ============ */
#result-screen.active{ display:flex; justify-content:center; padding:36px 16px; }
.result-card{
  background:var(--card);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  padding:36px;
  width:100%;
  max-width:680px;
  text-align:center;
}
.result-card h1{ font-size:22px; color:var(--blue-dark); margin-top:0; }
.score-ring{
  width:130px; height:130px;
  border-radius:50%;
  border:8px solid var(--blue-light);
  display:flex; align-items:center; justify-content:center;
  margin:16px auto;
  font-size:26px; font-weight:800; color:var(--blue-dark);
}
.score-subtext{ color:var(--ink-soft); font-size:13px; margin-bottom:24px; }

.stats-grid{
  display:grid; grid-template-columns:repeat(3,1fr); gap:10px;
  margin-bottom:26px;
}
.stat-box{
  background:var(--bg);
  border-radius:10px;
  padding:14px 8px;
}
.stat-box .num{ font-size:20px; font-weight:800; }
.stat-box .lbl{ font-size:11px; color:var(--ink-soft); margin-top:2px; }
.stat-box.answered .num{ color:var(--blue); }
.stat-box.correct .num{ color:var(--green); }
.stat-box.wrong .num{ color:var(--red); }

.review-list{ text-align:left; max-height:420px; overflow-y:auto; margin-bottom:24px; }
.review-item{
  border:1px solid var(--border);
  border-radius:10px;
  padding:12px 14px;
  margin-bottom:8px;
  font-size:13px;
}
.review-item .rq{ font-weight:600; margin-bottom:4px; }
.review-item .ra{ color:var(--ink-soft); }
.review-item.correct{ border-left:4px solid var(--green); }
.review-item.wrong{ border-left:4px solid var(--red); }
.review-item.unanswered{ border-left:4px solid #cbd2e0; }
.review-item.unknown{ border-left:4px solid var(--amber); }

/* ============ MODAL ============ */
.modal-overlay{
  position:fixed; inset:0; background:rgba(20,25,40,.5);
  display:flex; align-items:center; justify-content:center;
  z-index:100; padding:16px;
}
.modal-box{
  background:#fff; border-radius:14px; padding:26px; max-width:400px; width:100%;
}
.modal-box h2{ margin-top:0; font-size:18px; }
.modal-box p{ color:var(--ink-soft); font-size:14px; line-height:1.5; }
.modal-buttons{ display:flex; gap:10px; margin-top:20px; }
.modal-buttons .btn-ghost{ flex:1; text-decoration:none; border:1.5px solid var(--border); border-radius:9px; padding:11px; }
.modal-buttons .btn-primary{ flex:1; }

/* ============ RESPONSIVE ============ */
@media (max-width: 760px){
  .exam-body{ flex-direction:column; }
  .question-nav{
    width:100%; position:static; max-height:none;
    grid-template-columns:repeat(8,1fr);
  }
  .setup-card{ padding:24px; }
  .mode-options{ grid-template-columns:1fr; }
}