:root {
  --bg: #0b1020;
  --bg-alt: #111933;
  --panel: rgba(12, 18, 36, 0.94);
  --line: rgba(159, 177, 214, 0.18);
  --text: #edf2ff;
  --muted: #95a3c7;
  --muted-strong: #bfd0f3;
  --accent: #7bd6c4;
  --warning: #f2c266;
  --danger: #ff857b;
  --success: #67d08a;
  --shadow: 0 24px 60px rgba(2, 6, 18, 0.35);
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --sidebar-width: 300px;
  --inspector-width: 290px;
  --transition: 180ms ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  font-family: "Segoe UI Variable Text", "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(123, 214, 196, 0.18), transparent 28%),
    radial-gradient(circle at top right, rgba(242, 194, 102, 0.14), transparent 24%),
    linear-gradient(180deg, #07101f 0%, #090d18 52%, #06090f 100%);
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr) var(--inspector-width);
  min-height: 100vh;
}

.sidebar,
.inspector {
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: 28px 24px;
  background: rgba(5, 10, 22, 0.82);
  border-right: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.inspector {
  border-right: 0;
  border-left: 1px solid var(--line);
}

.workspace {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 28px 34px 20px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(7, 13, 26, 0.96), rgba(7, 13, 26, 0.76));
  backdrop-filter: blur(20px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.content {
  padding: 28px 34px 48px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.sidebar__brand h1,
.topbar h2,
.section-heading h3,
.subject-shell__intro h3,
.inspector h3 {
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  letter-spacing: -0.02em;
}

.sidebar__brand h1 {
  font-size: clamp(2rem, 3vw, 2.8rem);
  line-height: 1;
}

.sidebar__summary,
.section-copy,
.surface__header p,
.subject-shell__intro p,
.stat-block__detail,
.stack-item__meta,
.mini-stat__label {
  color: var(--muted);
  line-height: 1.6;
}

.sidebar__nav {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 32px;
}

.nav-link,
.button {
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 12px 16px;
  background: transparent;
  color: var(--muted-strong);
  transition: transform var(--transition), border-color var(--transition), background var(--transition), color var(--transition);
}

.nav-link:hover,
.nav-link:focus-visible,
.button:hover,
.button:focus-visible {
  outline: none;
  border-color: rgba(123, 214, 196, 0.35);
  background: rgba(123, 214, 196, 0.08);
  color: var(--text);
  transform: translateX(2px);
}

.nav-link.is-active {
  background: linear-gradient(90deg, rgba(123, 214, 196, 0.18), rgba(123, 214, 196, 0.04));
  border-color: rgba(123, 214, 196, 0.32);
  color: var(--text);
}

.button--ghost {
  border-color: var(--line);
}

.sidebar__footer {
  margin-top: auto;
  padding-top: 28px;
}

.mini-stat,
.readiness-pill,
.surface,
.stat-block,
.question-card,
.stack-item,
.controls-panel,
.passage-card,
.subject-summary,
.empty-state {
  background: linear-gradient(180deg, rgba(19, 28, 54, 0.92), rgba(11, 18, 35, 0.96));
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.readiness-pill {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 16px;
  min-width: 180px;
}

.readiness-pill span {
  color: var(--muted);
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.panel {
  display: none;
  animation: fadeUp 360ms ease;
}

.panel.is-visible {
  display: block;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.section-heading,
.surface__header,
.subject-shell {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
}

.subject-shell {
  margin-bottom: 24px;
}

.subject-shell__intro {
  max-width: 700px;
}

.stats-grid,
.three-up,
.dashboard-layout,
.two-up {
  display: grid;
  gap: 18px;
}

.stats-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 24px 0 18px;
}

.three-up {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.dashboard-layout,
.two-up {
  grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
  margin-top: 18px;
}

.stat-block,
.surface,
.controls-panel {
  padding: 22px;
}

.stat-block__label,
.stack-item__label,
.label {
  color: var(--muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.stat-block__value {
  display: block;
  margin-top: 10px;
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 700;
  line-height: 1;
}

.stat-block__value--small {
  font-size: 1.4rem;
  line-height: 1.2;
}

.stack-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.stack-item,
.empty-state {
  padding: 16px;
}

.surface__header {
  margin-bottom: 18px;
}

.progress-row {
  display: grid;
  grid-template-columns: minmax(120px, 1fr) minmax(0, 3fr) auto;
  gap: 16px;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid rgba(159, 177, 214, 0.08);
}

.progress-row:last-child {
  border-bottom: 0;
}

.progress-bar {
  position: relative;
  height: 12px;
  border-radius: 999px;
  background: rgba(159, 177, 214, 0.12);
  overflow: hidden;
}

.progress-bar__fill {
  position: absolute;
  inset: 0 auto 0 0;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), #4f94ff);
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  border-radius: 999px;
  font-size: 0.8rem;
  background: rgba(123, 214, 196, 0.1);
  color: var(--muted-strong);
  border: 1px solid rgba(123, 214, 196, 0.16);
}

.study-workspace {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.controls-panel {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 14px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.field select,
.field input,
.field textarea {
  width: 100%;
  padding: 12px 14px;
  color: var(--text);
  background: rgba(5, 10, 22, 0.56);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.button--primary {
  background: linear-gradient(90deg, var(--accent), #59a8ff);
  color: #041019;
  border-color: transparent;
  font-weight: 700;
}

.button--secondary {
  border-color: var(--line);
  background: rgba(159, 177, 214, 0.06);
}

.question-card {
  overflow: hidden;
}

.question-card__header,
.question-card__footer,
.passage-card,
.question-card__body {
  padding: 20px 22px;
}

.question-card__header,
.question-card__footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border-bottom: 1px solid rgba(159, 177, 214, 0.1);
}

.question-card__footer {
  border-top: 1px solid rgba(159, 177, 214, 0.1);
  border-bottom: 0;
}

.question-card__body {
  display: grid;
  gap: 18px;
}

.question-card__body h4,
.surface h4 {
  margin: 0;
  font-size: 1.15rem;
}

.passage-card p,
.question-card__body h4 {
  white-space: pre-line;
  line-height: 1.7;
}

.choices {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.question-nav {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(42px, 1fr));
  gap: 8px;
}

.question-nav__btn {
  border: 1px solid rgba(159, 177, 214, 0.18);
  border-radius: 10px;
  padding: 10px 0;
  background: rgba(8, 13, 25, 0.78);
  color: var(--muted-strong);
}

.question-nav__btn.is-current {
  border-color: rgba(123, 214, 196, 0.55);
  background: rgba(123, 214, 196, 0.16);
  color: var(--text);
}

.question-nav__btn.is-correct {
  border-color: rgba(103, 208, 138, 0.35);
}

.question-nav__btn.is-incorrect {
  border-color: rgba(255, 133, 123, 0.35);
}

.choice {
  display: flex;
  align-items: start;
  gap: 12px;
  padding: 14px 16px;
  border: 1px solid rgba(159, 177, 214, 0.12);
  border-radius: var(--radius-md);
  background: rgba(8, 13, 25, 0.7);
}

.choice.is-correct {
  border-color: rgba(103, 208, 138, 0.4);
  background: rgba(103, 208, 138, 0.1);
}

.choice.is-incorrect {
  border-color: rgba(255, 133, 123, 0.4);
  background: rgba(255, 133, 123, 0.1);
}

.explanation-box {
  padding: 16px;
  border-radius: var(--radius-md);
  background: rgba(79, 148, 255, 0.09);
  border: 1px solid rgba(79, 148, 255, 0.18);
  color: var(--muted-strong);
  line-height: 1.65;
}

.meta-line {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.chart {
  display: grid;
  gap: 12px;
}

.chart-row {
  display: grid;
  grid-template-columns: minmax(120px, 1fr) minmax(0, 4fr) auto;
  gap: 12px;
  align-items: center;
}

.chart-bar {
  height: 12px;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(159, 177, 214, 0.12);
}

.chart-bar__fill {
  height: 100%;
  background: linear-gradient(90deg, #7bd6c4, #59a8ff);
}

.activity-chart {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(42px, 1fr));
  gap: 10px;
  align-items: end;
  min-height: 220px;
}

.activity-bar {
  display: grid;
  gap: 8px;
  justify-items: center;
}

.activity-bar__value,
.activity-bar__sub {
  color: var(--muted);
  font-size: 0.76rem;
}

.activity-bar__track {
  width: 100%;
  height: 132px;
  display: flex;
  align-items: end;
  justify-content: center;
  padding: 8px;
  border-radius: 18px;
  background: rgba(8, 13, 25, 0.72);
  border: 1px solid rgba(159, 177, 214, 0.1);
}

.activity-bar__column {
  width: 100%;
  border-radius: 999px;
  background: linear-gradient(180deg, rgba(123, 214, 196, 0.95), rgba(79, 148, 255, 0.72));
}

.activity-bar__label {
  font-weight: 700;
}

.coverage-domain {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid rgba(159, 177, 214, 0.1);
}

.coverage-domain:first-of-type {
  margin-top: 0;
  padding-top: 0;
  border-top: 0;
}

.coverage-domain__header {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 18px;
  margin-bottom: 14px;
}

.coverage-domain__header h5 {
  margin: 0 0 6px;
  font-size: 1rem;
}

.coverage-domain__header p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.coverage-list {
  display: grid;
  gap: 12px;
}

.coverage-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 18px;
  align-items: center;
  padding: 16px;
  border-radius: var(--radius-md);
  border: 1px solid rgba(159, 177, 214, 0.1);
  background: rgba(8, 13, 25, 0.62);
}

.coverage-row__main {
  display: grid;
  gap: 10px;
}

@media (max-width: 1280px) {
  .app-shell {
    grid-template-columns: 260px minmax(0, 1fr);
  }

  .inspector {
    display: none;
  }

  .stats-grid,
  .three-up {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .controls-panel {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 960px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .topbar,
  .section-heading,
  .subject-shell {
    flex-direction: column;
    align-items: stretch;
  }

  .stats-grid,
  .three-up,
  .dashboard-layout,
  .two-up,
  .controls-panel {
    grid-template-columns: 1fr;
  }

  .coverage-row,
  .chart-row,
  .progress-row {
    grid-template-columns: 1fr;
  }

  .coverage-domain__header {
    display: flex;
    flex-direction: column;
  }

  .content {
    padding: 22px 18px 38px;
  }
}