/* ============ Reset + Base ============ */
*,*::before,*::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --teal: #0f766e;
  --teal-dark: #115e59;
  --teal-light: #14b8a6;
  --teal-bg: #f0fdfa;
  --gold: #ca8a04;
  --gold-light: #fef9c3;
  --green: #16a34a;
  --green-bg: #f0fdf4;
  --green-border: #86efac;
  --gray-50: #fafaf9;
  --gray-100: #f5f5f4;
  --gray-200: #e7e5e4;
  --gray-300: #d6d3d1;
  --gray-500: #78716c;
  --gray-700: #44403c;
  --gray-900: #1c1917;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow: 0 4px 12px rgba(15,118,110,0.08);
  --shadow-lg: 0 8px 24px rgba(15,118,110,0.12);
  --radius: 14px;
  --radius-sm: 8px;
}

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  font-family: 'Cairo', system-ui, -apple-system, sans-serif;
  background: linear-gradient(180deg, var(--gray-50) 0%, #fff 100%);
  color: var(--gray-900);
  line-height: 1.7;
  min-height: 100vh;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

.wrap {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 16px;
}

/* ============ Header ============ */
.site-header {
  background: linear-gradient(135deg, var(--teal) 0%, var(--teal-dark) 100%);
  color: #fff;
  padding: 20px 0 24px;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

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

.brand-mark {
  width: 48px;
  height: 48px;
  background: rgba(255,255,255,0.18);
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-weight: 800;
  font-size: 16px;
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.25);
}

.brand-text h1 {
  font-size: 20px;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.5px;
}

.tag {
  font-size: 13px;
  opacity: 0.85;
  margin-top: 2px;
  font-weight: 500;
}

.meta-pill {
  background: rgba(255,255,255,0.15);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  border: 1px solid rgba(255,255,255,0.2);
}

/* ============ Search Section ============ */
.search-section {
  background: #fff;
  padding: 20px 0 16px;
  border-bottom: 1px solid var(--gray-200);
  position: sticky;
  top: 92px;
  z-index: 40;
}

.search-box {
  position: relative;
  display: flex;
  align-items: center;
  background: var(--gray-100);
  border-radius: var(--radius);
  padding: 4px 14px;
  border: 2px solid transparent;
  transition: all 0.2s;
}

.search-box:focus-within {
  background: #fff;
  border-color: var(--teal);
  box-shadow: 0 0 0 4px rgba(15,118,110,0.1);
}

.search-icon {
  color: var(--gray-500);
  flex-shrink: 0;
}

#searchInput {
  flex: 1;
  border: 0;
  background: transparent;
  padding: 14px 12px;
  font-size: 16px;
  font-family: inherit;
  color: var(--gray-900);
  outline: none;
}

#searchInput::placeholder {
  color: var(--gray-500);
  font-weight: 400;
}

.clear-btn {
  background: var(--gray-300);
  border: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  font-size: 20px;
  line-height: 1;
  cursor: pointer;
  color: var(--gray-700);
  font-family: inherit;
  flex-shrink: 0;
  transition: background 0.15s;
}

.clear-btn:hover {
  background: var(--gray-500);
  color: #fff;
}

/* ============ Filters ============ */
.filters {
  display: flex;
  gap: 8px;
  margin-top: 14px;
  overflow-x: auto;
  padding-bottom: 4px;
  scrollbar-width: thin;
}

.filters::-webkit-scrollbar {
  height: 4px;
}

.filters::-webkit-scrollbar-thumb {
  background: var(--gray-300);
  border-radius: 2px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--gray-100);
  border: 1.5px solid transparent;
  border-radius: 999px;
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  color: var(--gray-700);
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
  transition: all 0.15s;
}

.chip:hover {
  background: var(--gray-200);
}

.chip-active {
  background: var(--teal);
  color: #fff;
  border-color: var(--teal-dark);
}

.chip-active:hover {
  background: var(--teal-dark);
}

.chip .count {
  background: rgba(0,0,0,0.08);
  padding: 1px 8px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
}

.chip-active .count {
  background: rgba(255,255,255,0.22);
}

.status-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 12px;
  font-size: 13px;
  color: var(--gray-500);
  flex-wrap: wrap;
  gap: 8px;
}

.status-bar .hint {
  font-style: italic;
}

#resultCount {
  font-weight: 600;
  color: var(--gray-700);
}

/* ============ Questions ============ */
.questions-list {
  padding: 20px 0 40px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.loading {
  text-align: center;
  padding: 60px 20px;
  color: var(--gray-500);
}

.q-card {
  background: #fff;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  overflow: hidden;
  transition: box-shadow 0.2s, transform 0.15s;
  box-shadow: var(--shadow-sm);
}

.q-card:hover {
  box-shadow: var(--shadow);
}

.q-header {
  padding: 16px 18px;
  cursor: pointer;
  display: flex;
  gap: 12px;
  align-items: flex-start;
  user-select: none;
}

.q-header:hover {
  background: var(--teal-bg);
}

.q-num {
  flex-shrink: 0;
  width: 38px;
  height: 38px;
  background: var(--teal-bg);
  color: var(--teal-dark);
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 14px;
  border: 1px solid #ccfbf1;
}

.q-body {
  flex: 1;
  min-width: 0;
}

.q-chapter {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  color: var(--gold);
  background: var(--gold-light);
  padding: 2px 8px;
  border-radius: 999px;
  margin-bottom: 6px;
  letter-spacing: 0.3px;
}

.q-text {
  font-size: 15.5px;
  font-weight: 600;
  color: var(--gray-900);
  line-height: 1.6;
}

.q-toggle {
  flex-shrink: 0;
  color: var(--gray-500);
  transition: transform 0.2s;
  font-size: 18px;
  margin-top: 6px;
}

.q-card.expanded .q-toggle {
  transform: rotate(180deg);
}

.q-content {
  display: none;
  padding: 0 18px 18px;
  border-top: 1px solid var(--gray-200);
  padding-top: 16px;
  background: linear-gradient(180deg, var(--gray-50) 0%, #fff 50px);
}

.q-card.expanded .q-content {
  display: block;
  animation: slideDown 0.25s ease-out;
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

.options {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 14px;
  background: #fff;
  border: 1.5px solid var(--gray-200);
  border-radius: var(--radius-sm);
  font-size: 14.5px;
  line-height: 1.55;
  transition: all 0.15s;
}

.option-letter {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--gray-100);
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 14px;
  color: var(--gray-700);
}

.option-correct {
  background: var(--green-bg);
  border-color: var(--green-border);
  color: #14532d;
  font-weight: 600;
}

.option-correct .option-letter {
  background: var(--green);
  color: #fff;
}

.option-correct::after {
  content: "✓";
  margin-right: auto;
  color: var(--green);
  font-weight: 900;
  font-size: 18px;
}

.explanation {
  background: var(--teal-bg);
  border-right: 4px solid var(--teal);
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  font-size: 14.5px;
  line-height: 1.7;
}

.explanation-label {
  font-weight: 800;
  color: var(--teal-dark);
  font-size: 13px;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.explanation-label::before {
  content: "💡";
  font-size: 16px;
}

.explanation-text {
  color: var(--gray-900);
}

/* ============ No Results ============ */
.no-results {
  text-align: center;
  padding: 60px 20px;
  color: var(--gray-500);
}

.no-results-icon {
  font-size: 48px;
  margin-bottom: 12px;
  opacity: 0.4;
}

.no-results p {
  font-size: 18px;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 4px;
}

.no-results span {
  font-size: 14px;
}

/* ============ Highlight ============ */
mark {
  background: var(--gold-light);
  color: var(--gray-900);
  padding: 0 3px;
  border-radius: 3px;
  font-weight: 700;
}

/* ============ Footer ============ */
.site-footer {
  background: var(--gray-100);
  border-top: 1px solid var(--gray-200);
  padding: 24px 0;
  margin-top: 40px;
  text-align: center;
  color: var(--gray-500);
  font-size: 13px;
}

.site-footer .sub {
  margin-top: 4px;
  font-size: 12px;
  opacity: 0.8;
}

/* ============ Responsive ============ */
@media (max-width: 600px) {
  .site-header { padding: 14px 0 18px; }
  .brand-mark { width: 42px; height: 42px; font-size: 14px; }
  .brand-text h1 { font-size: 17px; }
  .tag { font-size: 12px; }
  .meta-pill { font-size: 12px; padding: 4px 10px; }
  .search-section { top: 84px; padding: 14px 0; }
  #searchInput { font-size: 16px; padding: 12px 8px; }
  .chip { font-size: 13px; padding: 7px 12px; }
  .q-header { padding: 14px; gap: 10px; }
  .q-num { width: 34px; height: 34px; font-size: 13px; }
  .q-text { font-size: 14.5px; }
  .q-content { padding: 14px; padding-top: 14px; }
  .option { padding: 10px 12px; font-size: 14px; }
  .option-letter { width: 26px; height: 26px; font-size: 13px; }
  .explanation { padding: 12px 14px; font-size: 14px; }
}

@media (max-width: 380px) {
  .site-header .wrap { gap: 8px; }
  .meta-bar { width: 100%; }
  .meta-pill { display: block; text-align: center; }
}

/* ============ Print ============ */
@media print {
  .site-header, .search-section, .site-footer { display: none; }
  .q-card { break-inside: avoid; box-shadow: none; border: 1px solid #ccc; }
  .q-content { display: block !important; }
  .q-toggle { display: none; }
}