:root {
  --bg: #f5f6f1;
  --surface: #ffffff;
  --surface-2: #eef1e8;
  --ink: #17201d;
  --muted: #68736d;
  --line: #d8ded3;
  --accent: #1f7a5a;
  --accent-2: #b85c2d;
  --danger: #a43d37;
  --ok: #1f7a5a;
  --shadow: 0 18px 55px rgba(31, 42, 36, 0.10);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  letter-spacing: 0;
}

button,
input,
select {
  font: inherit;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 28px clamp(18px, 4vw, 48px) 18px;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 760;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: clamp(1.75rem, 4vw, 3.45rem);
  line-height: 0.98;
}

h2 {
  margin-bottom: 0;
  font-size: clamp(1.45rem, 3vw, 2.35rem);
  line-height: 1.05;
}

h3 {
  font-size: 1.04rem;
  line-height: 1.22;
}

p,
li {
  color: var(--muted);
  line-height: 1.58;
}

.deadline {
  min-width: 150px;
  border-left: 1px solid var(--line);
  padding-left: 22px;
}

.deadline span {
  display: block;
  color: var(--muted);
  font-size: 0.82rem;
}

.deadline strong {
  display: block;
  margin-top: 4px;
  font-size: 1rem;
}

main {
  padding: 24px clamp(14px, 3vw, 38px) 40px;
}

.workspace {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 24px;
  max-width: 1380px;
  margin: 0 auto;
}

.side-nav {
  position: sticky;
  top: 18px;
  align-self: start;
  display: grid;
  gap: 6px;
  padding: 8px;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.nav-item {
  min-height: 42px;
  padding: 10px 12px;
  background: transparent;
  border: 0;
  color: var(--muted);
  text-align: left;
  cursor: pointer;
  border-radius: 6px;
}

.nav-item:hover,
.nav-item.active {
  background: var(--ink);
  color: #fff;
}

.content {
  min-width: 0;
}

.view {
  display: none;
}

.view.active {
  display: block;
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 22px;
}

.small-button,
.primary-button,
.select,
.search {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  border-radius: 6px;
  min-height: 40px;
}

.small-button,
.primary-button {
  padding: 9px 13px;
  cursor: pointer;
}

.small-button:hover,
.primary-button:hover {
  border-color: var(--ink);
}

.primary-button {
  background: var(--ink);
  color: #fff;
}

.select,
.search {
  padding: 8px 12px;
}

.search {
  width: min(320px, 100%);
}

.priority-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 14px;
}

.priority,
.quiz-shell,
.flashcard,
.defense-box {
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.priority {
  min-height: 220px;
  padding: 22px;
}

.priority.primary {
  background: var(--ink);
  color: #fff;
}

.priority.primary p,
.priority.primary .rank {
  color: rgba(255, 255, 255, 0.78);
}

.rank {
  display: block;
  margin-bottom: 22px;
  color: var(--accent);
  font-size: 0.9rem;
  font-weight: 800;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  margin: 24px 0;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--line);
}

.metrics div {
  background: var(--surface);
  padding: 18px;
}

.metrics strong {
  display: block;
  font-size: 2rem;
  line-height: 1;
}

.metrics span {
  display: block;
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.9rem;
}

.split {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 26px;
  padding-top: 6px;
}

.large-quote {
  color: var(--ink);
  font-size: clamp(1.1rem, 2vw, 1.45rem);
  line-height: 1.42;
}

.compact-list {
  padding-left: 22px;
}

.architecture-hero {
  margin: 0 0 18px;
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.architecture-hero img {
  display: block;
  width: 100%;
  max-height: 680px;
  object-fit: contain;
  background: #fff;
}

.architecture-hero figcaption {
  padding: 12px 16px;
  color: var(--muted);
  border-top: 1px solid var(--line);
  font-size: 0.92rem;
}

.architecture-explain {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-bottom: 18px;
}

.architecture-explain section {
  background: var(--surface);
  border: 1px solid var(--line);
  padding: 18px;
}

.architecture-explain section:first-child {
  grid-row: span 2;
}

.architecture-gallery {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.architecture-gallery article {
  background: var(--surface);
  border: 1px solid var(--line);
  overflow: hidden;
}

.architecture-gallery img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: contain;
  background: #fff;
  border-bottom: 1px solid var(--line);
}

.architecture-gallery div {
  padding: 16px;
}

.architecture-gallery p,
.architecture-explain p,
.architecture-explain li {
  margin-bottom: 0;
}

.timeline,
.model-map,
.study-plan,
.qa-list,
.bank-list,
.relationship-list,
.relation-guide {
  display: grid;
  gap: 12px;
}

.timeline-item,
.model-item,
.plan-item,
.qa-item,
.relationship-item {
  display: grid;
  grid-template-columns: 118px minmax(0, 1fr);
  gap: 18px;
  padding: 18px;
  background: var(--surface);
  border: 1px solid var(--line);
}

.timeline-item strong,
.model-item strong,
.plan-item strong,
.relationship-item strong {
  color: var(--accent-2);
}

.timeline-item h3,
.model-item h3,
.plan-item h3,
.qa-item h3,
.relationship-item h3 {
  margin-bottom: 6px;
}

.timer-line {
  display: grid;
  grid-template-columns: 72px 1fr;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}

#timerText {
  font-weight: 800;
}

.timer-track {
  height: 10px;
  background: var(--line);
  overflow: hidden;
}

#timerBar {
  height: 100%;
  width: 100%;
  background: var(--accent);
  transition: width 0.25s linear;
}

.model-item {
  grid-template-columns: 170px minmax(0, 1fr);
}

.model-item ul,
.qa-item ul {
  margin: 10px 0 0;
  padding-left: 19px;
}

.model-item li,
.qa-item li,
.relationship-item li {
  margin: 4px 0;
}

.relation-intro {
  background: var(--surface);
  border: 1px solid var(--line);
  padding: 20px;
}

.relation-intro p {
  margin-bottom: 0;
}

.relationship-item {
  grid-template-columns: 190px minmax(0, 1fr);
}

.relationship-item ul {
  margin: 10px 0 0;
  padding-left: 19px;
}

.relation-visuals {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 14px 0 10px;
}

.relation-figure {
  margin: 0;
  padding: 12px;
  background: var(--surface-2);
  border: 1px solid var(--line);
}

.relation-figure figcaption {
  margin-bottom: 8px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.relation-figure svg {
  display: block;
  width: 100%;
  height: auto;
  min-height: 106px;
  background: #fbfcf8;
  border: 1px solid #dfe5dc;
}

.relation-figure svg text {
  fill: var(--ink);
  font-size: 13px;
  font-weight: 650;
}

.relation-figure svg .symbol {
  font-size: 19px;
  font-weight: 850;
}

.relation-figure svg .mini {
  fill: var(--muted);
  font-size: 11px;
}

.relation-figure p {
  margin: 8px 0 0;
  font-size: 0.86rem;
  line-height: 1.4;
}

.relationship-item em {
  color: var(--ink);
  font-style: normal;
  font-weight: 680;
}

.abbr-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.audit-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 14px;
  background: var(--line);
  border: 1px solid var(--line);
}

.audit-item {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr) auto;
  gap: 10px;
  align-items: center;
  background: var(--surface);
  padding: 11px 12px;
}

.audit-item strong {
  color: var(--accent-2);
}

.audit-item span {
  color: var(--muted);
  line-height: 1.35;
}

.audit-item em {
  color: var(--ok);
  font-style: normal;
  font-weight: 800;
}

.abbr-item {
  background: var(--surface);
  padding: 13px 14px;
}

.abbr-item strong {
  display: block;
  color: var(--accent-2);
}

.abbr-item span {
  display: block;
  margin-top: 3px;
  color: var(--muted);
  line-height: 1.4;
}

.quiz-controls {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.quiz-shell {
  padding: clamp(20px, 4vw, 34px);
}

.quiz-status {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.92rem;
  margin-bottom: 24px;
}

#quizQuestion {
  max-width: 880px;
  font-size: clamp(1.25rem, 3vw, 2rem);
}

.options {
  display: grid;
  gap: 10px;
  margin: 20px 0;
}

.option {
  min-height: 50px;
  padding: 13px 15px;
  background: var(--surface-2);
  border: 1px solid transparent;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
}

.option:hover {
  border-color: var(--ink);
}

.option.correct {
  background: rgba(31, 122, 90, 0.12);
  border-color: var(--ok);
}

.option.wrong {
  background: rgba(164, 61, 55, 0.10);
  border-color: var(--danger);
}

.feedback {
  min-height: 28px;
  color: var(--ink);
  font-weight: 620;
}

.flashcard {
  min-height: 340px;
  display: grid;
  align-content: center;
  gap: 18px;
  padding: clamp(24px, 5vw, 54px);
  cursor: pointer;
}

.flashcard span {
  color: var(--accent);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
}

.flashcard h3 {
  max-width: 900px;
  font-size: clamp(1.45rem, 4vw, 2.7rem);
  line-height: 1.08;
}

.flashcard p {
  display: none;
  max-width: 850px;
  color: var(--ink);
  font-size: clamp(1.08rem, 2vw, 1.38rem);
}

.flashcard.revealed p {
  display: block;
}

.flashcard small {
  color: var(--muted);
}

.card-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-top: 18px;
}

.defense-box {
  min-height: 150px;
  display: grid;
  align-content: center;
  padding: clamp(22px, 4vw, 34px);
  margin-bottom: 18px;
}

.defense-box h3 {
  font-size: clamp(1.25rem, 3vw, 2rem);
}

.qa-item {
  grid-template-columns: minmax(0, 1fr);
}

.bank-group {
  background: var(--surface);
  border: 1px solid var(--line);
}

.bank-group h3 {
  margin: 0;
  padding: 16px 18px;
  background: var(--ink);
  color: #fff;
}

.bank-item {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 14px;
  padding: 15px 18px;
  border-top: 1px solid var(--line);
}

.bank-number {
  color: var(--accent-2);
  font-weight: 800;
}

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

.bank-item p {
  margin-bottom: 0;
}

.qa-item button,
.plan-item button {
  justify-self: start;
}

.answer {
  display: none;
}

.qa-item.open .answer {
  display: block;
}

.plan-item {
  grid-template-columns: 86px minmax(0, 1fr) auto;
  align-items: start;
}

.plan-item.done {
  opacity: 0.62;
}

.plan-item.done h3 {
  text-decoration: line-through;
}

.plan-check {
  min-width: 40px;
  min-height: 40px;
}

@media (max-width: 900px) {
  .topbar,
  .section-head {
    align-items: start;
    flex-direction: column;
  }

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

  .side-nav {
    position: static;
    display: flex;
    overflow-x: auto;
  }

  .nav-item {
    white-space: nowrap;
  }

  .priority-grid,
  .metrics,
  .split,
  .architecture-explain,
  .architecture-gallery {
    grid-template-columns: 1fr;
  }

  .architecture-explain section:first-child {
    grid-row: auto;
  }

  .timeline-item,
  .model-item,
  .plan-item,
  .relationship-item,
  .relation-visuals,
  .audit-grid,
  .audit-item,
  .abbr-grid {
    grid-template-columns: 1fr;
  }
}

@media print {
  body {
    background: #fff;
  }

  .side-nav,
  .small-button,
  .primary-button,
  .select,
  .search,
  .card-actions {
    display: none !important;
  }

  .workspace,
  .priority-grid,
  .split,
  .metrics,
  .architecture-explain,
  .architecture-gallery {
    display: block;
  }

  .view {
    display: block;
    break-after: page;
  }

  .priority,
  .quiz-shell,
  .flashcard,
  .defense-box,
  .timeline-item,
  .model-item,
  .plan-item,
  .qa-item,
  .relationship-item,
  .relation-intro,
  .architecture-hero,
  .architecture-explain section,
  .architecture-gallery article {
    box-shadow: none;
    margin-bottom: 12px;
  }
}