:root {
  color-scheme: light;
  --paper: #fbfaf4;
  --ink: #162016;
  --muted: #657060;
  --line: #d8ddcf;
  --panel: #f1f4e8;
  --panel-strong: #e1ead4;
  --leaf: #315a36;
  --leaf-soft: #dcead6;
  --earth: #8a5934;
  --warning: #b56a1f;
  --wrong: #a33628;
  --right: #2d6b42;
  --white: #ffffff;
  --shadow: 0 18px 48px rgba(35, 49, 33, 0.12);
  font-family: Georgia, "Times New Roman", serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(49, 90, 54, 0.08) 1px, transparent 1px) 0 0 / 28px 28px,
    linear-gradient(180deg, #fbfaf4 0%, #f3f0e6 100%);
}

button,
select {
  font: inherit;
}

rhs-quiz-app,
rhs-question-card {
  display: block;
}

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(280px, 340px) 1fr;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--line);
  background: rgba(251, 250, 244, 0.92);
  backdrop-filter: blur(14px);
}

.brand {
  padding: 24px 22px 18px;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--earth);
  font: 700 12px/1.2 ui-sans-serif, system-ui, sans-serif;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: 30px;
  line-height: 1.02;
  letter-spacing: 0;
}

.score-panel {
  padding: 18px 22px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
}

.score-line {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 10px;
  font: 700 15px/1.3 ui-sans-serif, system-ui, sans-serif;
}

.progress-track {
  height: 10px;
  overflow: hidden;
  border: 1px solid rgba(49, 90, 54, 0.2);
  border-radius: 999px;
  background: var(--white);
}

.progress-bar {
  height: 100%;
  width: var(--progress, 0%);
  background: linear-gradient(90deg, var(--leaf), #75a05d);
  transition: width 180ms ease;
}

.meta-row {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 10px;
  color: var(--muted);
  font: 600 13px/1.3 ui-sans-serif, system-ui, sans-serif;
}

.controls {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  padding: 16px 22px;
  border-bottom: 1px solid var(--line);
}

.control-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.filter-select,
.action-button {
  min-height: 40px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  color: var(--ink);
}

.action-button {
  cursor: pointer;
  font: 700 13px/1 ui-sans-serif, system-ui, sans-serif;
}

.action-button.primary {
  border-color: var(--leaf);
  background: var(--leaf);
  color: var(--white);
}

.nav-list {
  flex: 1;
  overflow: auto;
  padding: 10px;
}

.nav-item {
  width: 100%;
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 10px;
  align-items: start;
  margin: 0 0 6px;
  padding: 10px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  text-align: left;
}

.nav-item:hover,
.nav-item:focus-visible {
  border-color: var(--line);
  background: var(--white);
  outline: none;
}

.nav-item[answered] {
  background: rgba(255, 255, 255, 0.64);
}

.nav-number {
  display: inline-grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--panel-strong);
  color: var(--leaf);
  font: 800 12px/1 ui-sans-serif, system-ui, sans-serif;
}

.nav-item[correct] .nav-number {
  background: var(--right);
  color: var(--white);
}

.nav-item[incorrect] .nav-number {
  background: var(--wrong);
  color: var(--white);
}

.nav-copy {
  min-width: 0;
  font: 600 13px/1.25 ui-sans-serif, system-ui, sans-serif;
}

.nav-topic {
  display: block;
  margin-top: 4px;
  color: var(--muted);
  font-size: 11px;
}

.main {
  min-width: 0;
  padding: 34px min(5vw, 64px) 72px;
}

.intro {
  max-width: 980px;
  margin: 0 auto 24px;
  padding-bottom: 18px;
  border-bottom: 2px solid var(--ink);
}

.intro h2 {
  margin: 0 0 8px;
  font-size: clamp(34px, 5vw, 64px);
  line-height: 0.95;
  letter-spacing: 0;
}

.intro p {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
  font: 500 16px/1.55 ui-sans-serif, system-ui, sans-serif;
}

.question-list {
  max-width: 980px;
  margin: 0 auto;
  display: grid;
  gap: 16px;
}

.question-card {
  scroll-margin-top: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.82);
  box-shadow: var(--shadow);
}

.question-card[correct] {
  border-color: rgba(45, 107, 66, 0.55);
}

.question-card[incorrect] {
  border-color: rgba(163, 54, 40, 0.55);
}

.question-header {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 18px 20px 0;
  color: var(--muted);
  font: 700 12px/1.2 ui-sans-serif, system-ui, sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.question-card h3 {
  margin: 10px 20px 18px;
  font-size: 23px;
  line-height: 1.22;
  letter-spacing: 0;
}

.options {
  display: grid;
  gap: 8px;
  padding: 0 20px 20px;
}

.option {
  display: grid;
  grid-template-columns: 28px 1fr;
  gap: 12px;
  align-items: start;
  width: 100%;
  min-height: 48px;
  padding: 11px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  text-align: left;
}

.option:hover:not(:disabled),
.option:focus-visible {
  border-color: var(--leaf);
  background: var(--leaf-soft);
  outline: none;
}

.option:disabled {
  cursor: default;
}

.option-marker {
  display: inline-grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--white);
  color: var(--leaf);
  font: 800 12px/1 ui-sans-serif, system-ui, sans-serif;
}

.option[correct] {
  border-color: var(--right);
  background: rgba(45, 107, 66, 0.12);
}

.option[incorrect] {
  border-color: var(--wrong);
  background: rgba(163, 54, 40, 0.12);
}

.feedback {
  margin: 0 20px 20px;
  padding: 14px 16px;
  border-left: 4px solid var(--leaf);
  border-radius: 0 8px 8px 0;
  background: var(--panel);
  font: 500 15px/1.45 ui-sans-serif, system-ui, sans-serif;
}

.feedback strong {
  display: block;
  margin-bottom: 4px;
}

.empty-state {
  padding: 18px 10px;
  color: var(--muted);
  font: 600 13px/1.4 ui-sans-serif, system-ui, sans-serif;
}

@media (max-width: 900px) {
  .app-shell {
    display: block;
  }

  .sidebar {
    position: relative;
    height: auto;
    max-height: 76vh;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .brand {
    padding: 18px 18px 14px;
  }

  h1 {
    font-size: 25px;
  }

  .score-panel,
  .controls {
    padding-left: 18px;
    padding-right: 18px;
  }

  .nav-list {
    max-height: 260px;
  }

  .main {
    padding: 24px 16px 56px;
  }

  .intro h2 {
    font-size: 38px;
  }

  .question-card h3 {
    font-size: 20px;
  }
}