:root {
  --paper: #f5f2ea;
  --surface: #fbfaf6;
  --surface-2: #efece3;
  --ink: #1b211c;
  --ink-soft: #454c45;
  --muted: #737970;
  --line: #d9d4c8;
  --line-strong: #bfb9ab;
  --green: #1f4a38;
  --green-2: #2b604a;
  --green-soft: #e6ede7;
  --gold: #9b743f;
  --serif: "Newsreader", "Noto Serif", Georgia, serif;
  --sans: "Be Vietnam Pro", "Noto Sans", system-ui, -apple-system, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --max: 1180px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0 0 auto;
  height: 3px;
  background: var(--green);
  z-index: 100;
}

::selection {
  background: var(--green);
  color: #fff;
}

a {
  color: inherit;
}

button,
input {
  font: inherit;
}

svg {
  display: block;
}

:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 2px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: -60px;
  left: 16px;
  z-index: 200;
  padding: 10px 14px;
  background: var(--green);
  color: #fff;
  font-size: 13px;
  text-decoration: none;
}

.skip-link:focus {
  top: 12px;
}

.app {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  display: flex;
  flex-direction: column;
  height: 100vh;
  padding: 36px 26px 28px;
  border-right: 1px solid var(--line);
  background: var(--paper);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  width: max-content;
  margin-bottom: 42px;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border-radius: 2px;
  background: var(--green);
  color: #f7f4ec;
  font-family: var(--serif);
  font-size: 22px;
  line-height: 1;
}

.brand-copy {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.brand-name {
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1;
}

.brand-note {
  color: var(--muted);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.18em;
  line-height: 1;
  text-transform: uppercase;
}

.nav-label {
  margin: 0 0 10px;
  padding-left: 12px;
  color: var(--muted);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.subject-nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-left: 2px solid transparent;
  color: var(--ink-soft);
  font-size: 13.5px;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.nav-link:hover {
  background: var(--surface);
  color: var(--ink);
}

.nav-link.is-active {
  border-left-color: var(--green);
  background: var(--green-soft);
  color: var(--green);
  font-weight: 600;
}

.nav-count {
  margin-left: auto;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10.5px;
  font-weight: 500;
}

.nav-link.is-active .nav-count {
  color: var(--green);
}

.sidebar-meta {
  margin-top: auto;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 11.5px;
  line-height: 1.7;
}

.sidebar-meta p {
  margin: 0;
}

.sidebar-meta a {
  color: var(--green);
  text-decoration: none;
  border-bottom: 1px solid rgba(31, 74, 56, 0.35);
}

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

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  border-bottom: 1px solid var(--line);
  background: rgba(245, 242, 234, 0.92);
  backdrop-filter: blur(14px);
}

.topbar-inner {
  display: flex;
  align-items: center;
  gap: 32px;
  width: 100%;
  max-width: var(--max);
  height: 72px;
  margin: 0 auto;
  padding: 0 48px;
}

.topbar-title {
  margin: 0;
  color: var(--muted);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  white-space: nowrap;
}

.search {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  max-width: 520px;
  height: 40px;
  margin-left: auto;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--surface);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.search:focus-within {
  border-color: var(--green);
  box-shadow: 0 0 0 3px rgba(31, 74, 56, 0.1);
}

.search-icon {
  flex: 0 0 auto;
  width: 17px;
  height: 17px;
  color: var(--muted);
}

.search input {
  flex: 1;
  min-width: 0;
  height: 100%;
  padding: 0;
  border: 0;
  border-radius: 0;
  outline: 0;
  background: transparent;
  color: var(--ink);
  font-size: 13.5px;
  -webkit-appearance: none;
  appearance: none;
}

.search input:focus-visible {
  outline: none;
}

.search input::placeholder {
  color: #92978f;
}

.search input::-webkit-search-cancel-button {
  display: none;
}

.search-kbd {
  flex: 0 0 auto;
  padding: 2px 5px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: var(--paper);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10px;
  line-height: 1.3;
}

.search.has-value .search-kbd {
  display: none;
}

.search-clear {
  display: grid;
  flex: 0 0 auto;
  place-items: center;
  width: 22px;
  height: 22px;
  padding: 0;
  border: 0;
  border-radius: 2px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
}

.search-clear[hidden] {
  display: none;
}

.search-clear:hover {
  background: var(--surface-2);
  color: var(--ink);
}

.search-clear svg {
  width: 14px;
  height: 14px;
}

.main {
  flex: 1;
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 56px 48px 36px;
}

.view {
  max-width: 920px;
}

.eyebrow {
  margin: 0;
  color: var(--green);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.hero-title {
  max-width: 18ch;
  margin: 12px 0 0;
  font-family: var(--serif);
  font-size: clamp(36px, 4.2vw, 54px);
  font-weight: 500;
  letter-spacing: -0.022em;
  line-height: 1.08;
  text-wrap: balance;
}

.hero-lede {
  max-width: 64ch;
  margin: 18px 0 0;
  color: var(--ink-soft);
  font-size: 15.5px;
  line-height: 1.7;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 22px;
  color: var(--muted);
  font-size: 11.5px;
}

.hero-meta span {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.hero-meta span + span::before {
  content: "";
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--line-strong);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 26px;
}

.subject-hero {
  padding-bottom: 34px;
  border-bottom: 1px solid var(--line);
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 40px;
  padding: 0 16px;
  border: 1px solid var(--green);
  border-radius: 2px;
  background: var(--green);
  color: #fff;
  font-size: 12.5px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.button:hover {
  background: var(--green-2);
  border-color: var(--green-2);
}

.button.ghost {
  border-color: var(--line-strong);
  background: transparent;
  color: var(--ink);
}

.button.ghost:hover {
  border-color: var(--ink-soft);
  background: var(--surface);
}

.button svg {
  width: 15px;
  height: 15px;
}

.section {
  margin-top: 40px;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 14px;
}

.section-title {
  margin: 0;
  font-family: var(--serif);
  font-size: 23px;
  font-weight: 500;
  letter-spacing: -0.01em;
}

.section-note {
  margin: 0;
  color: var(--muted);
  font-size: 11.5px;
}

.key-panel {
  padding: 18px;
  border: 1px solid var(--line);
  background: var(--surface);
}

.key-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 14px;
  color: var(--muted);
  font-size: 11px;
}

.key-legend strong {
  color: var(--ink);
  font-weight: 600;
}

.key-grid {
  display: grid;
  grid-template-columns: repeat(8, minmax(0, 1fr));
  gap: 5px;
}

.key-item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 4px;
  padding: 7px 8px;
  border: 1px solid var(--line);
  background: var(--paper);
  text-decoration: none;
  transition: background 0.15s ease, border-color 0.15s ease;
}

.key-item:hover {
  border-color: var(--green);
  background: var(--green-soft);
}

.key-num {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 9.5px;
}

.key-letter {
  color: var(--ink);
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 500;
}

.key-item:hover .key-letter {
  color: var(--green);
}

.question-list {
  border-top: 1px solid var(--line);
}

.question {
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 96px;
}

.question[open] {
  background: var(--surface);
}

.question summary {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr) 30px 18px;
  align-items: start;
  gap: 14px;
  padding: 17px 10px;
  list-style: none;
  cursor: pointer;
  transition: background 0.15s ease;
}

.question summary::-webkit-details-marker {
  display: none;
}

.question summary:hover {
  background: var(--surface);
}

.q-number {
  padding-top: 3px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10.5px;
}

.q-text {
  color: var(--ink);
  font-size: 14.5px;
  font-weight: 500;
  line-height: 1.55;
}

.q-answer {
  display: grid;
  place-items: center;
  width: 27px;
  height: 27px;
  border: 1px solid var(--line-strong);
  background: var(--green-soft);
  color: var(--green);
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
}

.q-chevron {
  width: 16px;
  height: 16px;
  margin-top: 5px;
  color: var(--muted);
  transition: transform 0.2s ease;
}

.question[open] .q-chevron {
  transform: rotate(180deg);
}

.question-body {
  padding: 0 10px 24px 62px;
}

.question-kind {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 9.5px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 9px 12px;
  border: 1px solid transparent;
  border-left: 2px solid transparent;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.55;
}

.option-key {
  flex: 0 0 18px;
  padding-top: 2px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 11px;
}

.option.is-correct {
  border-color: #d5e0d8;
  border-left-color: var(--green);
  background: var(--green-soft);
  color: var(--ink);
  font-weight: 500;
}

.option.is-correct .option-key {
  color: var(--green);
}

.option-tag {
  margin-left: auto;
  padding-top: 3px;
  color: var(--green);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  white-space: nowrap;
}

.explanation {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 12px;
  margin-top: 14px;
  padding: 13px 14px;
  border-left: 2px solid var(--gold);
  background: var(--paper);
  color: var(--ink-soft);
  font-size: 13px;
  line-height: 1.65;
}

.explanation-label {
  padding-top: 4px;
  color: var(--gold);
  font-size: 9.5px;
  font-weight: 700;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.explanation p {
  margin: 0;
}

.question.is-flash {
  animation: flash 1.6s ease-out;
}

@keyframes flash {
  0% {
    background: rgba(31, 74, 56, 0.14);
  }
  100% {
    background: transparent;
  }
}

.search-view .hero-title {
  max-width: none;
  font-size: clamp(30px, 3.6vw, 44px);
  overflow-wrap: anywhere;
}

.search-view .hero-meta {
  margin-top: 14px;
}

.filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 26px 0 4px;
}

.filter {
  padding: 7px 12px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: transparent;
  color: var(--ink-soft);
  font-size: 11.5px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.filter:hover {
  border-color: var(--line-strong);
  background: var(--surface);
}

.filter.is-active {
  border-color: var(--green);
  background: var(--green);
  color: #fff;
}

.filter span {
  margin-left: 3px;
  font-family: var(--mono);
  font-size: 10px;
  opacity: 0.72;
}

.search-results {
  margin-top: 18px;
}

.search-result {
  display: block;
  padding: 18px 12px;
  border-bottom: 1px solid var(--line);
  border-left: 2px solid transparent;
  text-decoration: none;
  transition: background 0.15s ease, border-color 0.15s ease;
}

.search-result:hover {
  border-left-color: var(--green);
  background: var(--surface);
}

.result-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.result-meta .subject {
  color: var(--green);
}

.result-title {
  margin: 0 0 7px;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 500;
  line-height: 1.35;
}

.result-answer {
  margin: 0 0 6px;
  color: var(--green);
  font-size: 12.5px;
  font-weight: 500;
}

.result-snippet {
  max-width: 72ch;
  margin: 0;
  color: var(--ink-soft);
  font-size: 13px;
  line-height: 1.6;
}

mark {
  padding: 0 1px;
  background: #efe0b8;
  color: inherit;
}

.empty {
  padding: 56px 24px;
  border: 1px dashed var(--line-strong);
  text-align: center;
  color: var(--muted);
}

.empty h2 {
  margin: 0 0 8px;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 500;
}

.empty p {
  max-width: 48ch;
  margin: 0 auto;
  font-size: 13.5px;
  line-height: 1.7;
}

.search-empty {
  margin-top: 24px;
}

.search-tips {
  margin-top: 20px;
  padding: 14px 16px;
  border-left: 2px solid var(--gold);
  background: var(--surface);
  color: var(--ink-soft);
  font-size: 12.5px;
  line-height: 1.7;
}

.search-tips strong {
  color: var(--ink);
  font-weight: 600;
}

.doc-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 28px;
}

.doc-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  border: 1px solid var(--line);
  background: var(--surface);
}

.doc-card h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: 21px;
  font-weight: 500;
  line-height: 1.25;
}

.doc-card p {
  margin: 0;
  color: var(--muted);
  font-size: 12.5px;
  line-height: 1.6;
}

.doc-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10.5px;
}

.doc-card .button {
  align-self: flex-start;
  margin-top: auto;
}

.doc-note {
  margin-top: 28px;
  padding: 16px 18px;
  border-left: 2px solid var(--gold);
  background: var(--surface);
  color: var(--ink-soft);
  font-size: 13px;
  line-height: 1.7;
}

.doc-note strong {
  color: var(--ink);
  font-weight: 600;
}

.footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 16px;
  margin-top: 64px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 11px;
}

.footer p {
  margin: 0;
}

.footer a {
  color: var(--green);
  text-decoration: none;
}

@media (max-width: 1040px) {
  .app {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    flex-direction: row;
    align-items: center;
    gap: 24px;
    height: auto;
    padding: 16px 24px;
    overflow-x: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .brand {
    flex: 0 0 auto;
    margin-bottom: 0;
  }

  .brand-mark {
    width: 30px;
    height: 30px;
    font-size: 18px;
  }

  .brand-name {
    font-size: 16px;
  }

  .nav-label,
  .sidebar-meta {
    display: none;
  }

  .subject-nav {
    flex: 1;
    flex-direction: row;
    gap: 2px;
  }

  .nav-link {
    padding: 8px 10px;
    border-left: 0;
    border-bottom: 2px solid transparent;
    font-size: 12.5px;
    white-space: nowrap;
  }

  .nav-link.is-active {
    border-left-color: transparent;
    border-bottom-color: var(--green);
  }

  .nav-count {
    display: none;
  }

  .topbar-inner {
    height: 64px;
    padding: 0 24px;
    gap: 20px;
  }

  .topbar-title {
    display: none;
  }

  .search {
    max-width: none;
    margin-left: 0;
  }

  .main {
    padding: 40px 24px 32px;
  }

  .key-grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .doc-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .sidebar {
    flex-wrap: wrap;
    gap: 10px 14px;
    padding: 12px 16px;
  }

  .subject-nav {
    flex-basis: 100%;
    gap: 0;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .nav-link {
    padding: 8px;
    font-size: 12px;
  }

  .brand-name {
    font-size: 15px;
  }

  .brand-note {
    display: none;
  }

  .subject-nav {
    overflow-x: auto;
    scrollbar-width: none;
  }

  .subject-nav::-webkit-scrollbar {
    display: none;
  }

  .topbar-inner {
    min-height: 60px;
    height: auto;
    padding: 10px 16px;
  }

  .main {
    padding: 30px 16px 24px;
  }

  .hero-title {
    font-size: 34px;
  }

  .hero-lede {
    font-size: 14.5px;
  }

  .section {
    margin-top: 32px;
  }

  .section-head {
    flex-direction: column;
    gap: 4px;
  }

  .key-panel {
    padding: 12px;
  }

  .key-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .question summary {
    grid-template-columns: 28px minmax(0, 1fr) 26px 16px;
    gap: 10px;
    padding: 14px 4px;
  }

  .question-body {
    padding: 0 4px 20px 38px;
  }

  .option {
    padding: 8px 9px;
    font-size: 13.5px;
  }

  .explanation {
    grid-template-columns: 1fr;
    gap: 4px;
    padding: 12px;
  }

  .explanation-label {
    padding-top: 0;
  }

  .result-title {
    font-size: 17px;
  }

  .footer {
    flex-direction: column;
    gap: 6px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

@media print {
  body::before,
  .sidebar,
  .topbar,
  .footer,
  .hero-actions,
  .filter-row {
    display: none;
  }

  .app {
    display: block;
  }

  .main {
    max-width: none;
    padding: 0;
  }

  .question {
    break-inside: avoid;
  }

  .question-body {
    display: block;
  }
}