:root {
  --u1-bg: #dceaf7;
  --u1-fg: #1f4e79;
  --u1-dot: #5a8fc4;
  --u2-bg: #e1f3e4;
  --u2-fg: #1f6b3a;
  --u2-dot: #4fa36c;
  --u3-bg: #f3e6fb;
  --u3-fg: #6a3aa0;
  --u3-dot: #9c6cd6;
  --u4-bg: #fbe4ea;
  --u4-fg: #a13a5c;
  --u4-dot: #d6739b;
  --u5-bg: #fdf3d7;
  --u5-fg: #8a6a1e;
  --u5-dot: #d6ab3e;
  --navy: #152238;
  --ink: #1c2530;
  --sub: #6b7686;
  --bg: #f4f1ea;
  --card: #ffffff;
  --line: #e7e2d6;
  --accent: #c9a876;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Inter", sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
.wrap {
  max-width: 560px;
  margin: 0 auto;
  min-height: 100vh;
  background: var(--bg);
  overflow-x: hidden;
}

/* ---------- Header ---------- */
.header {
  background: var(--navy);
  color: #dfe6f2;
  padding: 26px 22px 22px;
}
.eyebrow {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px;
  letter-spacing: 0.12em;
  color: #8fa2c2;
  margin-bottom: 14px;
}
.header h1 {
  font-family: "Fraunces", serif;
  font-weight: 700;
  font-size: 30px;
  line-height: 1.15;
  margin: 0 0 12px;
  color: #fff;
  letter-spacing: -0.01em;
}
.header .sub {
  font-size: 13px;
  color: #9fabc2;
  line-height: 1.6;
}

/* ---------- Subject toggle ---------- */
.subject-toggle {
  display: flex;
  gap: 8px;
  padding: 14px 22px 0;
  background: var(--card);
}
.subject-toggle button {
  flex: 1;
  padding: 9px 8px;
  border-radius: 9px;
  border: 1px solid var(--line);
  background: #faf8f3;
  font-family: "JetBrains Mono", monospace;
  font-size: 11.5px;
  color: var(--sub);
  cursor: pointer;
}
.subject-toggle button.active {
  background: var(--navy);
  color: #fff;
  border-color: var(--navy);
}

/* ---------- Tabs ---------- */
.tabbar-wrap {
  background: var(--card);
  padding: 16px 0 0;
  border-bottom: 1px solid var(--line);
  position: relative;
}
.tabbar {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding: 0 22px 12px;
  scrollbar-width: none;
}
.tabbar::-webkit-scrollbar {
  display: none;
}
.tab {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 9px 14px;
  border-radius: 20px;
  border: 1px solid var(--line);
  background: #faf8f3;
  color: var(--sub);
  font-weight: 600;
  font-size: 13.5px;
  cursor: pointer;
  white-space: nowrap;
}
.tab.active {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}
.scroll-track {
  height: 3px;
  background: #efe9db;
  margin: 0 22px 0;
  border-radius: 2px;
  position: relative;
  overflow: hidden;
}
.scroll-thumb {
  position: absolute;
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: none;
}

/* ---------- Unit card ---------- */
.unit-card {
  margin: 18px 22px 0;
  border-radius: 22px;
  padding: 22px 20px;
}
.unit-card .row {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  margin-bottom: 14px;
}
.unit-icon {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background: #ffffffb0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  flex-shrink: 0;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.06);
}
.unit-card h2 {
  font-family: "Fraunces", serif;
  font-weight: 700;
  font-size: 21px;
  margin: 2px 0 0;
  line-height: 1.25;
}
.unit-card .desc {
  font-size: 13.5px;
  line-height: 1.65;
  opacity: 0.85;
  margin-bottom: 16px;
}
.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 8px;
}
.chip {
  font-size: 12.5px;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 20px;
  background: #ffffffb0;
}
.chip.total {
  background: #fff;
  font-family: "JetBrains Mono", monospace;
}

/* ---------- Filter panel ---------- */
.filters {
  margin: 18px 22px 0;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px;
}
.filter-label {
  font-family: "JetBrains Mono", monospace;
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--sub);
  text-transform: uppercase;
  margin: 0 0 10px;
}
.filter-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-bottom: 16px;
}
.pill-btn {
  padding: 9px 10px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: #faf8f3;
  color: var(--ink);
  font-size: 12.5px;
  font-weight: 500;
  cursor: pointer;
  text-align: center;
}
.pill-btn.active {
  background: var(--navy);
  color: #fff;
  border-color: var(--navy);
}
.marks-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}
.marks-row .pill-btn {
  flex: 0 0 auto;
  padding: 8px 14px;
}

.search-box {
  position: relative;
  margin-bottom: 12px;
}
.search-box input {
  width: 100%;
  padding: 11px 12px 11px 34px;
  border-radius: 11px;
  border: 1px solid var(--line);
  background: #faf8f3;
  font-size: 13.5px;
  font-family: "Inter";
  color: var(--ink);
}
.search-box input:focus {
  outline: none;
  border-color: var(--accent);
}
.search-box svg {
  position: absolute;
  left: 11px;
  top: 12px;
  opacity: 0.45;
}

.util-row {
  display: flex;
  gap: 8px;
}
.util-row .pill-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.result-count {
  margin: 20px 22px 12px;
  font-family: "JetBrains Mono", monospace;
  font-size: 12.5px;
  color: var(--sub);
}

/* ---------- Question cards ---------- */
.q-list {
  padding: 0 22px 60px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.q-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 16px 16px 14px;
}
.q-head {
  display: flex;
  justify-content: space-between;
  gap: 10px;
}
.q-text {
  font-size: 14.5px;
  line-height: 1.65;
  color: var(--ink);
  flex: 1;
  min-width: 0;
}
.q-text .katex {
  font-size: 1.02em;
}
.q-text .katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 4px 0;
}
.bookmark-btn {
  background: none;
  border: none;
  cursor: pointer;
  padding: 2px;
  color: #b8b0a0;
  flex-shrink: 0;
}
.bookmark-btn.on {
  color: var(--accent);
}
.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 12px;
}
.tag {
  font-size: 11.5px;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 14px;
}
.tag.season-summer {
  background: #fcebd8;
  color: #a15a1e;
}
.tag.season-winter {
  background: #dceaf7;
  color: #1f4e79;
}
.tag.season-or {
  background: #f3e6fb;
  color: #6a3aa0;
}
.tag.marks {
  background: var(--navy);
  color: #fff;
}
.q-id {
  font-family: "JetBrains Mono", monospace;
  font-size: 10.5px;
  color: #b3aa98;
  margin-top: 8px;
}

.empty {
  margin: 0 22px;
  text-align: center;
  padding: 50px 20px;
  color: var(--sub);
  border: 1.5px dashed var(--line);
  border-radius: 16px;
}
.empty .big {
  font-family: "Fraunces", serif;
  font-size: 18px;
  color: var(--ink);
  margin-bottom: 8px;
}
.empty p {
  font-size: 13px;
  line-height: 1.6;
  max-width: 380px;
  margin: 0 auto;
}

/* ---------- Data Table formatting ---------- */
.q-table-wrap {
  overflow-x: auto;
  margin-top: 12px;
  margin-bottom: 4px;
  border-radius: 8px;
  border: 1px solid var(--line);
}
.q-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  text-align: center;
  background: #faf8f5;
}
.q-table th {
  background: #ede8dd;
  color: var(--navy);
  font-weight: 600;
  padding: 6px 12px;
  border: 1px solid var(--line);
  white-space: nowrap;
}
.q-table td {
  padding: 6px 12px;
  border: 1px solid var(--line);
  color: var(--ink);
  white-space: nowrap;
}

/* ---------- Original Image / Photo formatting ---------- */
.q-image-wrap {
  margin-top: 14px;
  margin-bottom: 8px;
  text-align: center;
  display: flex;
  justify-content: center;
}
.q-image {
  max-width: 100%;
  max-height: 380px;
  border-radius: 12px;
  border: 1px solid var(--line);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
  object-fit: contain;
  background: #ffffff;
  padding: 8px;
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}