:root{
  /* Dark theme with high contrast (avoid black-on-black) */
  --bg: #0b0f17;
  --card: rgba(255,255,255,0.06);
  --card2: rgba(255,255,255,0.08);
  --border: rgba(255,255,255,0.10);
  --text: rgba(255,255,255,0.92);
  --muted: rgba(255,255,255,0.65);
  --muted2: rgba(255,255,255,0.50);
  --accent: rgba(255,255,255,0.92);
  --ok: rgba(58, 185, 117, 0.95);
  --bad: rgba(240, 80, 80, 0.95);
  --shadow: 0 20px 60px rgba(0,0,0,0.55);
  --radius: 18px;
  --radius2: 14px;
  --pad: 18px;
  --maxw: 980px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono","Courier New", monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, "Noto Sans", "Liberation Sans", sans-serif;
}

*{ box-sizing: border-box; }
html, body{ height:100%; }
body{
  margin:0;
  font-family: var(--sans);
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
  font-size: 16px;
  line-height: 1.55;
}

/* Prevent browser defaults causing black text on dark backgrounds */
button,
input,
select,
textarea{
  color: var(--text);
  font-family: var(--sans);
}
button{ background: transparent; }
input::placeholder,
textarea::placeholder{ color: rgba(255,255,255,0.45); }

.bg{
  position: fixed;
  inset: 0;
  background:
    radial-gradient(900px 500px at 20% 10%, rgba(255,255,255,0.08), transparent 60%),
    radial-gradient(700px 450px at 80% 0%, rgba(255,255,255,0.06), transparent 55%),
    radial-gradient(800px 600px at 50% 90%, rgba(255,255,255,0.05), transparent 60%),
    linear-gradient(180deg, rgba(255,255,255,0.02), transparent 35%, rgba(255,255,255,0.02));
  pointer-events:none;
}

.topbar{
  position: sticky;
  top:0;
  z-index: 5;
  backdrop-filter: blur(10px);
  background: rgba(0,0,0,0.35);
  border-bottom: 1px solid var(--border);
  padding: 14px 16px;
  display:flex;
  align-items:center;
  justify-content: space-between;
  gap: 12px;
}

.brand-title{
  font-weight: 700;
  letter-spacing: 0.2px;
}
.brand-sub{
  font-size: 12px;
  color: var(--muted);
  margin-top: 2px;
}

.wrap{
  max-width: var(--maxw);
  margin: 18px auto 40px;
  padding: 0 14px;
}

.card{
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: var(--pad);
}

.controls{ margin-top: 14px; }

.controls-grid{
  display: grid;
  grid-template-columns: 1.2fr 0.7fr 1.1fr 1fr;
  gap: 14px;
}
@media (max-width: 980px){
  .controls-grid{ grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px){
  .controls-grid{ grid-template-columns: 1fr; }
  .topbar{ flex-direction: column; align-items: flex-start; }
  .top-actions{ width: 100%; }
}

.control-block{
  background: rgba(0,0,0,0.25);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius2);
  padding: 14px;
}

.label{
  font-size: 12px;
  color: var(--muted);
  display:block;
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.hint{
  font-size: 13px;
  color: var(--muted2);
  line-height: 1.45;
  margin: 10px 0 0;
}

.select{
  width: 100%;
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(0,0,0,0.35);
  color: var(--text);
  font-size: 15px;
  outline: none;
}

.topic-list{
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  max-height: 220px;
  overflow: auto;
  padding-right: 4px;
}

.topic-item{
  display:flex;
  align-items:center;
  gap: 10px;
  padding: 10px 10px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(0,0,0,0.28);
}

.topic-item input{ transform: scale(1.1); }
.topic-item span{ font-size: 14px; }

.topic-list{
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  max-height: 220px;
  overflow: auto;
  padding-right: 4px;
}

.theme-list{
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  max-height: 220px;
  overflow: auto;
  padding-right: 4px;
}

.theme-item{
  display:flex;
  align-items:center;
  gap: 10px;
  padding: 10px 10px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.10);
  background: rgba(0,0,0,0.25);
}

.theme-item input{ transform: scale(1.1); }
.theme-item span{ font-size: 14px; }

.segmented{
  display:flex;
  gap: 8px;
  background: rgba(0,0,0,0.28);
  border: 1px solid rgba(255,255,255,0.10);
  padding: 6px;
  border-radius: 14px;
}
.seg-btn{
  flex: 1;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(0,0,0,0.25);
  color: var(--text);
  border-radius: 12px;
  padding: 10px 10px;
  font-weight: 650;
  cursor: pointer;
}
.seg-btn.active{
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.20);
}

.status{ font-size: 14px; color: var(--text); }
.status .muted{ color: var(--muted); }
.status-row{
  display:flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 10px;
}

.pill{
  display:inline-flex;
  padding: 6px 10px;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(0,0,0,0.25);
  font-size: 12px;
  color: var(--muted);
}

.top-actions, .mini-actions{ display:flex; gap: 10px; flex-wrap: wrap; }
.btn{
  appearance:none;
  border: 1px solid rgba(255,255,255,0.14);
  background: rgba(255,255,255,0.10);
  color: var(--text);
  border-radius: 12px;
  padding: 10px 12px;
  font-weight: 650;
  cursor: pointer;
}
.btn:hover{ background: rgba(255,255,255,0.14); }
.btn:active{ transform: translateY(1px); }
.btn-secondary{
  background: rgba(0,0,0,0.28);
}
.btn-tertiary{
  background: rgba(0,0,0,0.18);
  font-weight: 600;
  padding: 8px 10px;
}

.hidden{ display:none !important; }

.quiz{ margin-top: 16px; }
.quiz-head{
  display:flex;
  align-items:flex-start;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
}
.topic{ font-size: 13px; color: var(--muted); }
.qmeta{ display:flex; gap: 8px; flex-wrap: wrap; justify-content:flex-end; }

.question{
  font-size: clamp(20px, 3.2vw, 28px);
  line-height: 1.35;
  margin: 10px 0 14px;
}

.options{
  display:grid;
  gap: 10px;
}
.option{
  width: 100%;
  text-align: left;
  background: rgba(0,0,0,0.25);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 14px;
  padding: 12px 12px;
  cursor: pointer;
  font-size: 16px;
  line-height: 1.45;
  color: var(--text);
}

.lockbar{
  display:flex;
  gap: 10px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.lockbar .btn{ flex: 1; min-width: 180px; }

.lock-hint{ color: var(--muted); font-size: 13px; margin-top: 6px; }
.option:hover{ background: rgba(255,255,255,0.08); }
.option[disabled]{ cursor: default; opacity: 0.95; }

/* Selected option (used in exam mode before locking, and for review) */
.option.chosen{
  border-color: rgba(255, 200, 90, 0.55);
  box-shadow: 0 0 0 2px rgba(255,200,90,0.14) inset;
  background: rgba(255, 200, 90, 0.06);
}

/* Locked answer (exam mode) */
.option.locked{
  border-color: rgba(255, 200, 90, 0.70);
  box-shadow: 0 0 0 2px rgba(255,200,90,0.20) inset;
}

.option.correct{
  border-color: rgba(58, 185, 117, 0.55);
  box-shadow: 0 0 0 2px rgba(58,185,117,0.12) inset;
}
.option.wrong{
  border-color: rgba(240, 80, 80, 0.55);
  box-shadow: 0 0 0 2px rgba(240,80,80,0.12) inset;
}

.feedback{
  margin-top: 14px;
  border-radius: 16px;
  padding: 14px;
  border: 1px solid rgba(255,255,255,0.10);
  background: rgba(0,0,0,0.25);
}
.feedback h3{
  margin: 0 0 8px;
  font-size: 14px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
}
.feedback .explain{
  font-size: 14px;
  line-height: 1.5;
  color: var(--text);
  margin: 8px 0 0;
}
.feedback .explain-item{
  border-top: 1px dashed rgba(255,255,255,0.10);
  padding-top: 10px;
  margin-top: 10px;
}
.feedback .tag{
  font-family: var(--mono);
  font-size: 12px;
  color: var(--muted);
}

.nav{
  display:flex;
  gap: 10px;
  justify-content: space-between;
  margin-top: 16px;
  flex-wrap: wrap;
}
.nav .btn{ flex: 1; min-width: 140px; }

.results{ margin-top: 16px; }
.results h2{ margin: 0 0 6px; }
.result-summary{ color: var(--text); line-height: 1.5; margin: 8px 0 14px; }

.review-controls{ display:flex; gap:10px; flex-wrap: wrap; margin-bottom: 14px; }

.review{
  display:grid;
  gap: 10px;
}
.review-item{
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: 16px;
  background: rgba(0,0,0,0.25);
  padding: 12px;
}
.review-item .rtop{
  display:flex;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
}
.review-item .rquestion{ margin: 8px 0 10px; font-weight: 700; }
.review-item .ropt{
  margin: 6px 0;
  font-size: 14px;
  line-height: 1.4;
  color: var(--text);
}
.review-item .ropt.correct{ color: rgba(58,185,117,0.95); }
.review-item .ropt.wrong{ color: rgba(240,80,80,0.95); }
.review-item .rexplain{ margin-top: 10px; font-size: 13px; color: var(--muted); line-height: 1.5; }

.footer{ margin-top: 18px; padding: 0 6px; }
.small{ font-size: 12px; }
.muted{ color: var(--muted); }

/* Glossary */
.glossary-head{
  display:flex;
  gap: 10px;
  align-items:center;
  justify-content: space-between;
  flex-wrap: wrap;
}
.glossary-search{
  width: 100%;
  max-width: 520px;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(0,0,0,0.25);
  color: var(--text);
  outline: none;
}
.glossary-meta{ color: var(--muted); font-size: 13px; }
.glossary-list{ display: grid; gap: 10px; margin-top: 14px; }
.glossary-group{ margin-top: 10px; }
.glossary-group h3{ margin: 16px 0 8px; font-size: 13px; color: var(--muted); text-transform: uppercase; letter-spacing: 0.10em; }
.glossary-item{ border: 1px solid rgba(255,255,255,0.12); border-radius: 14px; padding: 12px; background: rgba(0,0,0,0.25); }
.glossary-term{ font-weight: 800; font-size: 16px; }
.glossary-term .tr{ font-weight: 600; color: rgba(255,255,255,0.86); }
.glossary-desc{ margin-top: 6px; color: rgba(255,255,255,0.86); line-height: 1.5; font-size: 14px; }



/* Feedback breakdown */
.feedback { line-height: 1.4; }
.fb-title { font-weight: 700; margin-bottom: 6px; }
.fb-sub { margin: 4px 0; }
.fb-breakdown { margin-top: 10px; display: grid; gap: 8px; }
.bd-row { border: 1px solid rgba(255,255,255,0.12); border-radius: 10px; padding: 10px; background: rgba(255,255,255,0.04); }
.bd-head { font-weight: 600; margin-bottom: 6px; }
.bd-tag { display: inline-block; font-size: 12px; padding: 2px 8px; border-radius: 999px; margin-right: 8px; border: 1px solid rgba(255,255,255,0.18); }
.bd-reason { color: rgba(255,255,255,0.85); font-size: 14px; }
.bd-correct .bd-tag { }
.bd-chosen .bd-tag { }
.bd-wrong .bd-tag { }

/* Better mobile spacing */
@media (max-width: 560px){
  .controls-grid{ grid-template-columns: 1fr; }
  .topbar{ position: sticky; top: 0; z-index: 10; }
  .question{ font-size: 20px; }
  .option{ padding: 14px; }
}


/* Glossary A–Z navigation */
.glossary-az{
  display:flex;
  flex-wrap:wrap;
  gap:6px;
  margin-top:10px;
}
.az-btn{
  padding:6px 10px;
  border-radius:10px;
  border:1px solid rgba(255,255,255,.16);
  background: rgba(255,255,255,.06);
  color: rgba(255,255,255,.92);
  font-weight:600;
  cursor:pointer;
}
.az-btn:hover{ background: rgba(255,255,255,.10); }
.az-btn.disabled{
  opacity:.35;
  cursor:not-allowed;
}