:root {
  --white: #ffffff;
  --surface: #f7f9fc;
  --surface-blue: #f4f7ff;
  --ink: #0b0f18;
  --ink-soft: #2b3340;
  --muted: #697386;
  --rule: #dfe4eb;
  --rule-strong: #b6c0ce;
  --cobalt: #135fd1;
  --cobalt-bright: #1b66e3;
  --cobalt-soft: #eaf1ff;
  --teal: #087c84;
  --teal-soft: #e7f5f4;
  --danger: #a23a4a;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --serif: "Iowan Old Style", "Songti SC", "STSong", serif;
  --header-h: 104px;
  /* Keep the detail rail near one quarter of the viewport. At narrower desktop
     widths a fixed 374px rail overpowered the timeline, especially at 100% zoom. */
  --source-w: clamp(300px, 24vw, 374px);
  --label-w: 216px;
  --period-w: 228px;
  --shadow-float: 0 24px 70px rgba(12, 24, 45, 0.16);
}

* { box-sizing: border-box; }

html {
  min-width: 320px;
  min-height: 100%;
  color-scheme: light;
  background: var(--white);
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  overflow: hidden;
  color: var(--ink);
  background: var(--white);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: geometricPrecision;
}

button, input, select, textarea { color: inherit; font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { border: 0; background: none; }
a { color: inherit; }

svg {
  width: 1.15em;
  height: 1.15em;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.6;
}

::selection { color: var(--white); background: var(--cobalt); }
:focus-visible { outline: 2px solid var(--cobalt-bright); outline-offset: 3px; }
.paper-grain { display: none; }

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

.site-header {
  position: relative;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  padding: 0 32px;
  border-bottom: 1px solid var(--rule-strong);
  background: rgba(255, 255, 255, 0.97);
}

.brand {
  display: flex;
  align-items: center;
  gap: 18px;
  text-decoration: none;
  white-space: nowrap;
}

.brand-mark {
  display: flex;
  width: 164px;
  height: 46px;
  flex: 0 0 164px;
  align-items: center;
  color: var(--ink);
}

.brand-mark-ai {
  position: relative;
  display: block;
  width: 65px;
  flex: 0 0 65px;
  font-family: "Iowan Old Style", "Times New Roman", Georgia, serif;
  font-size: 37px;
  font-weight: 600;
  letter-spacing: -0.075em;
  line-height: 1;
}

.brand-mark-slash {
  position: absolute;
  top: 3px;
  right: 1px;
  width: 8px;
  height: 34px;
  background: var(--cobalt-bright);
  transform: skewX(-17deg);
}

.brand-mark-name {
  position: relative;
  display: block;
  width: 96px;
  height: 46px;
  flex: 0 0 96px;
  margin-left: 3px;
  font-family: var(--serif);
}

.brand-mark-name::after {
  position: absolute;
  top: 33px;
  left: 12px;
  z-index: 0;
  width: 63px;
  height: 1px;
  background: currentColor;
  content: "";
  opacity: 0.9;
}

.brand-mark-char {
  position: absolute;
  z-index: 1;
  display: block;
  font-weight: 600;
  line-height: 1;
  transform-origin: center;
}

.brand-mark-char.is-world { top: 11px; left: 0; font-size: 29px; }
.brand-mark-char.is-boundary { top: 5px; left: 28px; font-size: 33px; }
.brand-mark-char.is-line { top: 13px; left: 59px; font-size: 30px; transform: rotate(-1deg); }

.brand-sub { color: var(--muted); font-size: 12px; letter-spacing: 0.08em; }
.primary-nav { display: flex; align-self: stretch; gap: 30px; }

.nav-item {
  position: relative;
  display: grid;
  place-items: center;
  min-width: 54px;
  padding: 2px 0 0;
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
  letter-spacing: 0.08em;
  text-decoration: none;
}

.nav-item::after,
.view-button::after {
  position: absolute;
  right: 0;
  bottom: -1px;
  left: 0;
  height: 2px;
  background: var(--cobalt);
  content: "";
  opacity: 0;
  transform: scaleX(0.2);
  transition: opacity 160ms ease, transform 160ms ease;
}

.nav-item:hover, .nav-item.is-active { color: var(--ink); }
.nav-item.is-active::after, .view-button.is-active::after { opacity: 1; transform: scaleX(1); }
.mobile-header-actions, .mobile-nav { display: none; }
#app { height: calc(100vh - var(--header-h)); outline: none; }

/* Timeline shell */
.timeline-screen {
  display: grid;
  grid-template-columns: minmax(0, 1fr) var(--source-w);
  width: 100%;
  height: 100%;
  min-height: 0;
  background: var(--white);
}

.timeline-main {
  display: grid;
  grid-template-rows: 78px minmax(0, 1fr) 48px;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
}

.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-width: 0;
  gap: 28px;
  padding: 0 26px 0 30px;
  border-bottom: 1px solid var(--rule);
  background: var(--white);
}

.view-switch { display: flex; flex: 0 0 auto; min-width: 0; align-items: stretch; align-self: stretch; gap: 17px; }

.filter-group { display: flex; min-width: max-content; align-items: stretch; gap: 17px; }

.filter-label {
  align-self: center;
  color: #9aa3b1;
  font-size: 9px;
  font-weight: 650;
  letter-spacing: 0.12em;
  white-space: nowrap;
}

.view-divider {
  align-self: center;
  width: 1px;
  height: 18px;
  background: var(--rule-strong);
}

.view-button {
  position: relative;
  padding: 2px 0 0;
  color: var(--muted);
  cursor: pointer;
  font-size: 12px;
  font-weight: 580;
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.view-button::after { transform: scaleX(0.35); }
.view-button:hover, .view-button.is-active { color: var(--ink); }
.view-button[data-topic="world-model"].is-active { color: var(--teal); }
.view-button[data-topic="world-model"].is-active::after { background: var(--teal); }

.search-box {
  display: flex;
  flex: 1 1 480px;
  align-items: center;
  width: auto;
  min-width: 220px;
  max-width: 480px;
  height: 38px;
  padding: 0 12px;
  border-bottom: 1px solid var(--rule-strong);
  color: var(--muted);
  transition: border-color 160ms ease, color 160ms ease;
}

.search-box:focus-within { border-color: var(--cobalt); color: var(--cobalt); }
.search-box svg { flex: 0 0 auto; width: 17px; height: 17px; }

.search-box input {
  width: 100%;
  height: 100%;
  padding: 0 0 0 10px;
  border: 0;
  outline: none;
  background: transparent;
  font-size: 13px;
}

.search-box input::placeholder { color: #8b94a3; }

.timeline-viewport {
  position: relative;
  min-width: 0;
  min-height: 0;
  overflow: auto;
  overscroll-behavior: contain;
  background: var(--white);
  scrollbar-color: var(--rule-strong) transparent;
  scrollbar-width: thin;
}

.timeline-viewport::-webkit-scrollbar { width: 8px; height: 8px; }
.timeline-viewport::-webkit-scrollbar-thumb {
  border: 2px solid transparent;
  border-radius: 10px;
  background: var(--rule-strong);
  background-clip: padding-box;
}

.desktop-board {
  position: relative;
  display: flex;
  flex-direction: column;
  width: calc(var(--label-w) + var(--period-count) * var(--period-w));
  min-width: 100%;
  min-height: 100%;
  background-color: var(--white);
  background-image: linear-gradient(to right, transparent calc(var(--period-w) - 1px), rgba(223, 228, 235, 0.58) calc(var(--period-w) - 1px));
  background-position: var(--label-w) 0;
  background-size: var(--period-w) 100%;
}

.period-header, .timeline-row {
  display: grid;
  grid-template-columns: var(--label-w) repeat(var(--period-count), var(--period-w));
  width: max-content;
  min-width: 100%;
}

.period-header {
  position: sticky;
  top: 0;
  z-index: 20;
  min-height: 54px;
  border-bottom: 1px solid var(--rule-strong);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px);
}

.period-range, .period-cell { display: flex; align-items: center; }

.period-range {
  position: sticky;
  left: 0;
  z-index: 22;
  justify-content: space-between;
  padding: 0 13px;
  border-right: 1px solid var(--rule-strong);
  background: rgba(255, 255, 255, 0.98);
  color: var(--ink-soft);
}

.period-range span { font-size: 10px; font-weight: 620; letter-spacing: 0.1em; }

.period-range button {
  display: grid;
  width: 27px;
  height: 27px;
  place-items: center;
  color: var(--muted);
  cursor: pointer;
}

.period-range button:hover { color: var(--cobalt); }

.period-cell {
  justify-content: center;
  border-right: 1px solid rgba(223, 228, 235, 0.6);
  color: var(--muted);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  font-weight: 590;
  letter-spacing: 0.08em;
}

.period-cell.is-current { color: var(--cobalt); }

.timeline-row { min-height: 228px; border-bottom: 1px solid var(--rule-strong); }

.timeline-row.row-tech {
  min-height: 244px;
  background: linear-gradient(90deg, rgba(244, 247, 255, 0.72), rgba(255, 255, 255, 0) 48%);
}

.row-label {
  position: sticky;
  left: 0;
  z-index: 16;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 27px 26px 24px 30px;
  border-right: 1px solid var(--rule-strong);
  background: rgba(255, 255, 255, 0.98);
}

.row-label h2 {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 7px;
  margin: 0;
  font-size: 25px;
  font-weight: 650;
  letter-spacing: -0.045em;
}

.row-label p { max-width: 148px; margin: 0; color: var(--muted); font-size: 10px; line-height: 1.7; }
.row-tech .row-label { color: var(--cobalt); background: rgba(249, 251, 255, 0.98); }
.row-tech .row-label p { color: var(--muted); }

.timeline-cell {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 1px;
  min-width: 0;
  padding: 14px 12px 13px;
  border-right: 1px solid rgba(223, 228, 235, 0.58);
  overflow: hidden auto;
}

.event-entry {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 3px 8px;
  width: 100%;
  padding: 9px 8px 9px 14px;
  border-left: 1px solid var(--ink);
  color: var(--ink-soft);
  text-align: left;
  cursor: pointer;
  transition: color 140ms ease, background 140ms ease, border-color 140ms ease;
}

.event-entry::before {
  position: absolute;
  top: 14px;
  left: -3px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: currentColor;
  content: "";
}

.event-entry:hover { background: var(--surface); }

.event-entry strong {
  min-width: 0;
  overflow: hidden;
  font-size: 11px;
  font-weight: 690;
  letter-spacing: -0.01em;
  line-height: 1.35;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.event-date { color: var(--muted); font-size: 8px; font-variant-numeric: tabular-nums; letter-spacing: 0.02em; line-height: 1.8; }

.event-summary {
  grid-column: 1 / -1;
  display: -webkit-box;
  overflow: hidden;
  color: var(--muted);
  font-size: 9px;
  line-height: 1.45;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 1;
}

.row-tech .event-entry { border-left-color: var(--cobalt); color: var(--cobalt); }
.event-entry.topic-world-model { border-left-color: var(--teal); color: var(--teal); }

.event-entry.is-selected {
  z-index: 2;
  outline: 1px solid currentColor;
  outline-offset: -1px;
  background: var(--white);
}

.event-entry.is-selected .event-summary, .event-entry.is-selected .event-date { color: var(--ink-soft); }
.event-entry.is-major strong { font-weight: 760; }
.timeline-cell.is-dense { padding-top: 10px; }
.timeline-cell.is-dense .event-entry { padding-top: 7px; padding-bottom: 7px; }
.timeline-cell.is-dense .event-summary { display: none; }
.timeline-cell.is-dense .event-entry::before { top: 12px; }

.current-line {
  position: absolute;
  top: 43px;
  bottom: 0;
  left: calc(var(--label-w) + (var(--current-index) + 0.73) * var(--period-w));
  z-index: 14;
  width: 1px;
  background: var(--cobalt);
  pointer-events: none;
}

.current-line span {
  position: sticky;
  top: 7px;
  display: inline-block;
  padding: 3px 5px;
  color: var(--white);
  background: var(--cobalt);
  font-size: 8px;
  font-weight: 650;
  letter-spacing: 0.1em;
  transform: translateX(-50%);
}

.mobile-chronology { display: none; }

.timeline-footer {
  position: relative;
  z-index: 21;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 0 23px 0 30px;
  border-top: 1px solid var(--rule-strong);
  background: var(--white);
}

.timeline-hint { color: var(--muted); font-size: 9px; font-variant-numeric: tabular-nums; letter-spacing: 0.08em; }
.timeline-utilities { display: flex; align-items: center; gap: 18px; }

.utility-button { display: flex; align-items: center; gap: 5px; color: var(--muted); cursor: pointer; font-size: 9px; }
.utility-button svg { width: 14px; height: 14px; }
.utility-button:hover { color: var(--cobalt); }

/* Source pane */
.source-panel {
  position: relative;
  z-index: 30;
  min-width: 0;
  min-height: 0;
  overflow: hidden auto;
  border-left: 1px solid var(--rule-strong);
  background: var(--white);
}

.source-panel-inner, .empty-selection { padding: 31px 27px 34px; }

.source-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 18px;
  color: var(--cobalt);
  font-size: 9px;
  font-weight: 690;
  letter-spacing: 0.12em;
}

.source-panel-head::after { width: 42px; height: 1px; background: var(--cobalt); content: ""; }

.selection-heading {
  margin: 26px 0 7px;
  font-family: var(--serif);
  font-size: clamp(29px, 2.4vw, 38px);
  font-weight: 500;
  letter-spacing: -0.045em;
  line-height: 1.02;
}

.selection-date { color: var(--muted); font-size: 9px; font-variant-numeric: tabular-nums; letter-spacing: 0.08em; }
.selection-summary { margin: 23px 0 33px; color: var(--ink-soft); font-size: 12px; line-height: 1.85; }

.source-count, .detail-source-title {
  padding-bottom: 10px;
  border-bottom: 1px solid var(--ink);
  color: var(--ink);
  font-size: 10px;
  font-weight: 680;
  letter-spacing: 0.08em;
}

.bibliography-list { display: flex; flex-direction: column; }

.bibliography-row {
  display: grid;
  grid-template-columns: 25px minmax(0, 1fr);
  gap: 10px;
  padding: 16px 0 15px;
  border-bottom: 1px solid var(--rule);
  text-decoration: none;
}

.bibliography-icon { display: grid; width: 23px; height: 23px; place-items: center; color: var(--cobalt); }
.bibliography-icon svg { width: 17px; height: 17px; }
.bibliography-copy { display: grid; min-width: 0; gap: 4px; }
.bibliography-copy strong { font-size: 10px; font-weight: 670; line-height: 1.45; }
.bibliography-copy > span, .bibliography-copy time { color: var(--muted); font-size: 8px; line-height: 1.35; }

.bibliography-host {
  grid-column: 2;
  overflow: hidden;
  color: var(--cobalt);
  font-size: 8px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.bibliography-row:hover strong { color: var(--cobalt); }

.source-detail-button {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  margin-top: 30px;
  padding: 12px 0;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  color: var(--ink);
  cursor: pointer;
  font-size: 10px;
  font-weight: 660;
  letter-spacing: 0.07em;
}

.source-detail-button:hover { color: var(--cobalt); border-color: var(--cobalt); }
.source-panel-actions {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 43px;
  margin-top: 30px;
}
.source-panel-actions .source-detail-button { margin-top: 0; }
.source-link-button {
  display: grid;
  width: 43px;
  place-items: center;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  border-left: 1px solid var(--rule);
  color: var(--muted);
  cursor: pointer;
}
.source-link-button svg { width: 15px; height: 15px; }
.source-link-button:hover { color: var(--cobalt); border-color: var(--cobalt); }
.empty-selection { color: var(--muted); font-size: 13px; line-height: 1.7; }
.empty-selection strong { color: var(--ink); }

/* Detail drawer */
.detail-backdrop {
  position: fixed;
  inset: 0;
  z-index: 80;
  background: rgba(5, 11, 22, 0.24);
  opacity: 0;
  pointer-events: none;
  transition: opacity 180ms ease;
}

.detail-backdrop.is-open { opacity: 1; pointer-events: auto; }

.detail-drawer {
  position: fixed;
  top: var(--header-h);
  right: 0;
  bottom: 0;
  z-index: 90;
  width: min(580px, 92vw);
  overflow: auto;
  border-left: 1px solid var(--rule-strong);
  background: var(--white);
  box-shadow: var(--shadow-float);
  transform: translateX(104%);
  transition: transform 220ms cubic-bezier(0.22, 0.8, 0.25, 1);
}

.detail-drawer.is-open { transform: translateX(0); }
.drawer-handle { display: none; }

.detail-drawer-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  padding: 35px 38px 32px;
  border-bottom: 1px solid var(--rule-strong);
}

.detail-drawer-head > div > span { color: var(--cobalt); font-size: 9px; font-weight: 680; letter-spacing: 0.12em; }

.detail-drawer-head h2 {
  margin: 17px 0 8px;
  font-family: var(--serif);
  font-size: 38px;
  font-weight: 500;
  letter-spacing: -0.045em;
  line-height: 1.05;
}

.detail-drawer-head time { color: var(--muted); font-size: 9px; letter-spacing: 0.08em; }
.drawer-actions { display: flex; flex: 0 0 auto; gap: 7px; }

.icon-button {
  display: grid;
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  place-items: center;
  border: 1px solid var(--rule);
  color: var(--muted);
  cursor: pointer;
}

.icon-button:hover { color: var(--cobalt); border-color: var(--cobalt); }
.detail-body { padding: 31px 38px 50px; }
.detail-section { margin-bottom: 27px; }
.detail-section h3 { margin: 0 0 9px; color: var(--cobalt); font-size: 10px; font-weight: 680; letter-spacing: 0.08em; }
.detail-section p { margin: 0; color: var(--ink-soft); font-size: 13px; line-height: 1.8; }
.tag-list { display: flex; flex-wrap: wrap; gap: 7px; }
.tag { padding: 5px 8px; border: 1px solid var(--rule-strong); color: var(--muted); font-size: 9px; }
.detail-source-title { margin-top: 38px; }
.detail-source-row { border-bottom: 1px solid var(--rule); }
.detail-source-row .bibliography-row { border-bottom: 0; }

.detail-source-row > button {
  display: flex;
  align-items: center;
  gap: 5px;
  margin: -7px 0 10px 35px;
  color: var(--muted);
  cursor: pointer;
  font-size: 8px;
}

.detail-source-row > button:hover { color: var(--cobalt); }

.library-controls input, .library-controls select {
  width: 100%;
  border: 1px solid var(--rule-strong);
  border-radius: 0;
  outline: none;
  background: var(--white);
}

.library-controls input:focus, .library-controls select:focus { border-color: var(--cobalt); }

.toast {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 120;
  padding: 11px 14px;
  color: var(--white);
  background: var(--ink);
  font-size: 11px;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 160ms ease, transform 160ms ease;
}

.toast.is-visible { opacity: 1; transform: translateY(0); }

/* Library and about */
.library-screen, .about-screen {
  height: 100%;
  overflow: auto;
  padding: 52px clamp(28px, 7vw, 112px) 80px;
  background: var(--white);
}

.page-head {
  display: grid;
  grid-template-columns: minmax(240px, 0.8fr) minmax(300px, 1.3fr);
  gap: 80px;
  align-items: end;
  padding-bottom: 34px;
  border-bottom: 1px solid var(--ink);
}

.page-head h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(44px, 5vw, 70px);
  font-weight: 500;
  letter-spacing: -0.055em;
  line-height: 0.95;
}

.page-head p { max-width: 650px; margin: 0; color: var(--muted); font-size: 13px; line-height: 1.75; }
.library-controls { display: grid; grid-template-columns: minmax(0, 1fr) 180px; gap: 12px; margin: 28px 0 22px; }
.library-controls input, .library-controls select { height: 42px; padding: 0 12px; font-size: 11px; }
.library-table { width: 100%; border-collapse: collapse; table-layout: fixed; }

.library-table th {
  padding: 10px 12px;
  border-bottom: 1px solid var(--ink);
  color: var(--muted);
  font-size: 9px;
  font-weight: 650;
  letter-spacing: 0.08em;
  text-align: left;
}

.library-table th:first-child { width: 95px; }
.library-table th:nth-child(2) { width: 42%; }
.library-table th:last-child { width: 92px; }

.library-table td {
  padding: 15px 12px;
  border-bottom: 1px solid var(--rule);
  color: var(--muted);
  font-size: 10px;
  line-height: 1.5;
  vertical-align: top;
}

.library-table td a { display: block; margin-bottom: 5px; color: var(--ink); font-size: 11px; font-weight: 650; text-decoration: none; }
.library-table td a:hover { color: var(--cobalt); }
.library-table td span { display: block; font-size: 9px; }
.about-grid {
  display: grid;
  grid-template-columns: minmax(260px, 0.8fr) minmax(360px, 1.3fr);
  gap: 80px;
  padding-top: 52px;
}

.about-lead {
  position: sticky;
  top: 20px;
  align-self: start;
  font-family: var(--serif);
  font-size: clamp(28px, 3vw, 44px);
  line-height: 1.3;
  letter-spacing: -0.04em;
}

.about-content { display: grid; gap: 0; border-top: 1px solid var(--ink); }

.about-content section {
  display: grid;
  grid-template-columns: 145px minmax(0, 1fr);
  gap: 25px;
  padding: 24px 0;
  border-bottom: 1px solid var(--rule);
}

.about-content h2, .about-content p { margin: 0; }
.about-content h2 { color: var(--cobalt); font-size: 11px; }
.about-content p { color: var(--ink-soft); font-size: 12px; line-height: 1.8; }
.about-content code { padding: 2px 4px; background: var(--surface); font-size: 0.92em; }
.about-content a { color: var(--cobalt); text-underline-offset: 3px; }

.empty-page {
  display: grid;
  min-height: 240px;
  place-items: center;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--rule);
  color: var(--muted);
  font-family: var(--serif);
  font-size: 18px;
}

@media (max-width: 1160px) {
  :root { --source-w: clamp(286px, 25.5vw, 300px); --label-w: 198px; --period-w: 216px; }
  .site-header { padding: 0 25px; }
  .brand-sub { display: none; }
  .toolbar { gap: 20px; padding-right: 20px; padding-left: 24px; }
  .view-switch, .filter-group { gap: 13px; }
  .view-button { font-size: 11px; }
  .source-panel-inner { padding-right: 23px; padding-left: 23px; }
}

@media (max-width: 1050px) {
  .timeline-screen { display: block; }
  .timeline-main { height: 100%; }
  .source-panel { display: none; }
}

@media (max-width: 900px) {
  :root { --source-w: 292px; --label-w: 184px; --period-w: 208px; }
  .primary-nav { gap: 19px; }
  .timeline-main { grid-template-rows: 72px minmax(0, 1fr) 45px; }
  .view-switch, .filter-group { gap: 12px; }
  .search-box { width: min(32vw, 360px); }
  .source-panel-inner { padding: 26px 18px 30px; }
  .selection-heading { font-size: 29px; }
}

@media (max-width: 760px) {
  :root { --header-h: 80px; }
  body { overflow: hidden; }
  .site-header { height: var(--header-h); padding: 0 18px; }
  .brand { gap: 0; }
  .brand-sub, .primary-nav { display: none; }
  .brand-mark { width: 139px; height: 39px; flex-basis: 139px; }
  .brand-mark-ai { width: 55px; flex-basis: 55px; font-size: 31px; }
  .brand-mark-slash { top: 3px; right: 1px; width: 7px; height: 28px; }
  .brand-mark-name { width: 81px; height: 39px; flex-basis: 81px; margin-left: 3px; }
  .brand-mark-name::after { top: 28px; left: 10px; width: 53px; }
  .brand-mark-char.is-world { top: 10px; left: 0; font-size: 24px; }
  .brand-mark-char.is-boundary { top: 5px; left: 24px; font-size: 28px; }
  .brand-mark-char.is-line { top: 12px; left: 50px; font-size: 25px; }
  .mobile-header-actions { display: flex; align-items: center; gap: 5px; }

  .header-icon-button {
    display: grid;
    width: 37px;
    height: 37px;
    place-items: center;
    color: var(--ink);
    cursor: pointer;
  }

  .header-icon-button svg { width: 20px; height: 20px; }

  .mobile-nav {
    position: fixed;
    top: calc(var(--header-h) - 1px);
    right: 0;
    z-index: 95;
    display: grid;
    width: min(240px, 72vw);
    padding: 12px 18px 18px;
    border-bottom: 1px solid var(--rule-strong);
    border-left: 1px solid var(--rule-strong);
    background: var(--white);
    box-shadow: 0 18px 40px rgba(11, 20, 36, 0.12);
    opacity: 0;
    pointer-events: none;
    transform: translateY(-8px);
    transition: opacity 150ms ease, transform 150ms ease;
  }

  .mobile-nav.is-open { opacity: 1; pointer-events: auto; transform: translateY(0); }

  .mobile-nav button, .mobile-nav a {
    padding: 13px 3px;
    border-bottom: 1px solid var(--rule);
    color: var(--ink);
    text-align: left;
    cursor: pointer;
    font-size: 12px;
    letter-spacing: 0.05em;
    text-decoration: none;
  }

  #app { height: calc(100dvh - var(--header-h)); }
  .timeline-screen { display: block; height: 100%; }

  .timeline-main {
    display: grid;
    grid-template-rows: auto minmax(0, 1fr) 42px;
    height: 100%;
  }

  .toolbar { display: grid; gap: 0; height: auto; padding: 0 17px 12px; }

  .view-switch {
    width: 100%;
    height: 53px;
    gap: 16px;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .filter-group { gap: 16px; }

  .view-switch::-webkit-scrollbar { display: none; }
  .view-button { flex: 0 0 auto; font-size: 11px; }
  .search-box { width: 100%; height: 36px; padding: 0; }
  .timeline-viewport { overflow-x: hidden; overflow-y: auto; }
  .desktop-board, .source-panel { display: none; }
  .mobile-chronology { display: block; width: 100%; min-height: 100%; }

  .mobile-range {
    position: sticky;
    top: 0;
    z-index: 18;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 50px;
    padding: 0 17px;
    border-bottom: 1px solid var(--rule-strong);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
  }

  .mobile-range span { color: var(--muted); font-size: 9px; font-weight: 650; letter-spacing: 0.09em; }

  .mobile-range button {
    display: grid;
    width: 31px;
    height: 31px;
    place-items: center;
    color: var(--muted);
    cursor: pointer;
  }

  .mobile-periods { position: relative; padding: 0 17px 40px; }

  .mobile-periods::before {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 30px;
    width: 1px;
    background: var(--cobalt);
    content: "";
  }

  .mobile-period { position: relative; padding: 29px 0 4px 33px; }

  .mobile-period-head {
    display: flex;
    align-items: baseline;
    gap: 9px;
    min-height: 33px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--rule-strong);
  }

  .mobile-period-node {
    position: absolute;
    top: 35px;
    left: 9px;
    width: 9px;
    height: 9px;
    border: 2px solid var(--white);
    border-radius: 50%;
    background: var(--cobalt);
    box-shadow: 0 0 0 1px var(--cobalt);
  }

  .mobile-period-head h2 { margin: 0; font-size: 18px; font-weight: 660; letter-spacing: -0.03em; }

  .mobile-period-head > span:last-child:not(.mobile-period-node) {
    color: var(--cobalt);
    font-size: 8px;
    font-weight: 650;
    letter-spacing: 0.09em;
  }

  .mobile-period-body { display: grid; }
  .mobile-group { padding: 19px 0 4px; border-bottom: 1px solid var(--rule); }
  .mobile-group h3 { margin: 0 0 7px; color: var(--ink); font-size: 9px; font-weight: 710; letter-spacing: 0.1em; }
  .mobile-group.group-tech h3 { color: var(--cobalt); }
  .mobile-group > div { display: grid; }

  .mobile-group .event-entry {
    grid-template-columns: minmax(0, 1fr) auto;
    padding: 12px 5px 12px 14px;
    border-left-color: var(--ink);
  }

  .mobile-group.group-tech .event-entry { border-left-color: var(--cobalt); color: var(--cobalt); }
  .mobile-group .event-entry.topic-world-model { border-left-color: var(--teal); color: var(--teal); }
  .mobile-group .event-entry strong { font-size: 12px; }
  .mobile-group .event-entry::before { top: 17px; }
  .mobile-group .event-summary { display: -webkit-box; font-size: 9px; -webkit-line-clamp: 2; }
  .mobile-group .event-entry.is-selected { outline: 1px solid currentColor; }

  .timeline-footer { height: 42px; padding: 0 16px; }
  .timeline-hint { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .timeline-utilities { gap: 3px; }
  .utility-button { display: grid; width: 30px; height: 30px; place-items: center; }
  .utility-button span { display: none; }
  .detail-backdrop { background: rgba(5, 11, 22, 0.36); }

  .detail-drawer {
    top: auto;
    right: 0;
    bottom: 0;
    left: 0;
    width: 100%;
    max-height: 86dvh;
    border: 0;
    border-top: 1px solid var(--rule-strong);
    border-radius: 14px 14px 0 0;
    transform: translateY(104%);
  }

  .detail-drawer.is-open { transform: translateY(0); }
  .drawer-handle { display: block; width: 37px; height: 4px; margin: 9px auto 0; border-radius: 3px; background: var(--rule-strong); }
  .detail-drawer-head { padding: 22px 19px 21px; }
  .detail-drawer-head h2 { margin-top: 12px; font-size: 31px; }
  .detail-body { padding: 22px 19px 45px; }
  .detail-section p { font-size: 12px; }

  .library-screen, .about-screen { padding: 32px 18px 60px; }
  .page-head { display: block; padding-bottom: 24px; }
  .page-head h1 { font-size: 48px; }
  .page-head p { margin-top: 20px; font-size: 12px; }
  .library-controls { grid-template-columns: 1fr; }
  .library-table, .library-table tbody, .library-table tr, .library-table td { display: block; }
  .library-table thead { display: none; }
  .library-table tr { position: relative; padding: 15px 0; border-bottom: 1px solid var(--rule); }
  .library-table td { padding: 2px 0; border: 0; }
  .library-table td:first-child { color: var(--cobalt); font-weight: 650; }
  .about-grid { display: block; padding-top: 32px; }
  .about-lead { position: static; margin-bottom: 35px; font-size: 30px; }
  .about-content section { grid-template-columns: 94px minmax(0, 1fr); gap: 14px; }
  .toast { right: 16px; bottom: 16px; left: 16px; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}