:root {
  color-scheme: light;
  --bg: #f5f6fa;
  --bg-elevated: rgba(255, 255, 255, 0.78);
  --surface: #ffffff;
  --surface-soft: #eef1f8;
  --surface-hover: #e8ecf6;
  --text: #11182b;
  --text-soft: #596277;
  --text-faint: #81899a;
  --line: rgba(30, 42, 72, 0.12);
  --line-strong: rgba(30, 42, 72, 0.2);
  --accent: #5269e8;
  --accent-strong: #3449c5;
  --accent-soft: rgba(82, 105, 232, 0.11);
  --violet: #8b62df;
  --glow-a: rgba(57, 143, 255, 0.17);
  --glow-b: rgba(137, 87, 255, 0.13);
  --success: #14795c;
  --shadow: 0 20px 65px rgba(41, 52, 91, 0.1);
  --shadow-tight: 0 10px 30px rgba(41, 52, 91, 0.11);
  --radius-xl: 30px;
  --radius-lg: 21px;
  --radius-md: 14px;
  --header-height: 68px;
  --page-width: 1180px;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #090c14;
  --bg-elevated: rgba(12, 16, 27, 0.8);
  --surface: #111624;
  --surface-soft: #171d2d;
  --surface-hover: #1c2437;
  --text: #eef2ff;
  --text-soft: #aab2c5;
  --text-faint: #777f91;
  --line: rgba(207, 219, 255, 0.11);
  --line-strong: rgba(207, 219, 255, 0.2);
  --accent: #8ea1ff;
  --accent-strong: #b2beff;
  --accent-soft: rgba(128, 149, 255, 0.14);
  --violet: #b491ff;
  --glow-a: rgba(49, 129, 255, 0.13);
  --glow-b: rgba(132, 77, 255, 0.13);
  --success: #60d4ad;
  --shadow: 0 24px 72px rgba(0, 0, 0, 0.3);
  --shadow-tight: 0 12px 34px rgba(0, 0, 0, 0.26);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  scroll-behavior: smooth;
  background: var(--bg);
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  color: var(--text);
  background:
    linear-gradient(rgba(255, 255, 255, 0) 0%, var(--bg) 44rem),
    var(--bg);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body.drawer-open {
  overflow: hidden;
}

button,
input {
  color: inherit;
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  border: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 68%, transparent);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  z-index: 1000;
  top: 10px;
  left: 10px;
  padding: 10px 15px;
  border-radius: 10px;
  color: #fff;
  background: #17234f;
  transform: translateY(-150%);
  transition: transform 160ms ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.ambient {
  position: fixed;
  z-index: -1;
  width: 52vw;
  height: 52vw;
  border-radius: 50%;
  pointer-events: none;
  filter: blur(105px);
}

.ambient-one {
  top: -28vw;
  left: -18vw;
  background: var(--glow-a);
}

.ambient-two {
  top: 22rem;
  right: -31vw;
  background: var(--glow-b);
}

.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  width: 100%;
  height: var(--header-height);
  padding: 0 max(24px, calc((100vw - var(--page-width)) / 2));
  border-bottom: 1px solid transparent;
  background: color-mix(in srgb, var(--bg-elevated) 88%, transparent);
  backdrop-filter: blur(18px) saturate(145%);
  transition: border-color 180ms ease, box-shadow 180ms ease;
}

.site-header.is-scrolled {
  border-color: var(--line);
  box-shadow: 0 5px 30px rgba(28, 37, 65, 0.05);
}

.brand {
  display: inline-flex;
  align-items: center;
  justify-self: start;
  gap: 9px;
  font-size: 16px;
  font-weight: 680;
  letter-spacing: -0.02em;
}

.brand-mark {
  display: grid;
  width: 30px;
  height: 30px;
  place-items: center;
  border: 1px solid color-mix(in srgb, var(--accent) 30%, var(--line));
  border-radius: 10px;
  color: var(--accent);
  background: var(--accent-soft);
  font-family: Georgia, serif;
  font-size: 22px;
}

.brand-muted {
  color: var(--text-soft);
  font-weight: 480;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: color-mix(in srgb, var(--surface) 72%, transparent);
}

.main-nav a {
  padding: 7px 15px;
  border-radius: 999px;
  color: var(--text-soft);
  font-size: 13px;
  transition: color 160ms ease, background 160ms ease;
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: var(--text);
  background: var(--surface-soft);
}

.icon-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-soft);
  background: color-mix(in srgb, var(--surface) 74%, transparent);
  cursor: pointer;
  transition: color 160ms ease, border-color 160ms ease, background 160ms ease;
}

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

.header-actions {
  display: flex;
  align-items: center;
  justify-self: end;
  gap: 8px;
}

.github-link,
.theme-toggle {
  gap: 7px;
  font-size: 12px;
}

.github-stars {
  color: var(--accent-strong);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

main {
  min-height: calc(100vh - var(--header-height));
}

.view {
  animation: view-in 220ms ease both;
}

@keyframes view-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

body.drawer-open .view {
  animation: none;
  opacity: 1;
}

.page-shell {
  width: min(calc(100% - 48px), var(--page-width));
  margin: 0 auto;
}

.loading-state,
.error-state,
.empty-state {
  display: grid;
  min-height: 55vh;
  place-content: center;
  justify-items: center;
  padding: 48px 24px;
  color: var(--text-soft);
  text-align: center;
}

.noscript-notice {
  width: min(calc(100% - 48px), 680px);
  margin: 12vh auto;
  padding: 32px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--surface);
  text-align: center;
}

.noscript-notice h1 { margin: 0 0 12px; }
.noscript-notice p { color: var(--text-soft); line-height: 1.7; }
.noscript-notice a { color: var(--accent-strong); text-decoration: underline; text-underline-offset: 3px; }

.loading-orbit {
  width: 38px;
  height: 38px;
  border: 1px solid var(--line-strong);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 900ms linear infinite;
}

@keyframes spin { to { transform: rotate(1turn); } }

.error-state h1,
.empty-state h2 {
  margin: 0 0 10px;
  color: var(--text);
}

.local-preview-help {
  max-width: 720px;
  margin: 0 auto;
}

.preview-command {
  display: block;
  max-width: calc(100vw - 40px);
  margin: 10px 0 8px;
  padding: 14px 18px;
  overflow-x: auto;
  border: 1px solid var(--line-strong);
  border-radius: 12px;
  color: var(--accent-strong);
  background: var(--surface);
  box-shadow: var(--shadow-tight);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 13px;
  text-align: left;
  user-select: all;
  white-space: nowrap;
}

.hero {
  position: relative;
  display: grid;
  min-height: min(820px, calc(100vh - var(--header-height)));
  align-items: center;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.hero::before {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse at 72% 50%, black 0%, transparent 68%);
  content: "";
  opacity: .55;
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.04fr) minmax(410px, .96fr);
  align-items: center;
  gap: clamp(30px, 6vw, 92px);
  width: min(calc(100% - 48px), var(--page-width));
  margin: 0 auto;
  padding: 75px 0 90px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 18px;
  color: var(--accent-strong);
  font-size: 12px;
  font-weight: 650;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.eyebrow::before {
  width: 20px;
  height: 1px;
  background: currentColor;
  content: "";
}

.hero h1 {
  max-width: 680px;
  margin: 0;
  font-size: clamp(45px, 6.4vw, 82px);
  font-weight: 610;
  letter-spacing: -.07em;
  line-height: 1.04;
}

.gradient-text {
  color: transparent;
  background: linear-gradient(105deg, var(--accent-strong), var(--violet));
  background-clip: text;
  -webkit-background-clip: text;
}

.hero-copy {
  max-width: 620px;
  margin: 25px 0 0;
  color: var(--text-soft);
  font-size: clamp(16px, 1.65vw, 20px);
  line-height: 1.8;
}

.hero-actions,
.inline-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 11px;
  margin-top: 32px;
}

.button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0 19px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  cursor: pointer;
  font-size: 14px;
  font-weight: 610;
  transition: transform 170ms ease, box-shadow 170ms ease, border-color 170ms ease;
}

.button:hover {
  border-color: var(--line-strong);
  box-shadow: var(--shadow-tight);
  transform: translateY(-1px);
}

.button-primary {
  border-color: var(--accent-strong);
  color: #fff;
  background: #3449c5;
}

html[data-theme="dark"] .button-primary {
  border-color: #8498ff;
  color: #0a0e1b;
  background: #9aabff;
}

.button-ghost {
  background: transparent;
}

.hero-note {
  margin-top: 25px;
  color: var(--text-faint);
  font-size: 12px;
}

.math-visual {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  max-height: 540px;
}

.math-visual::before,
.math-visual::after {
  position: absolute;
  border-radius: 50%;
  content: "";
  filter: blur(30px);
}

.math-visual::before {
  inset: 15%;
  background: radial-gradient(circle at 35% 35%, var(--glow-a), transparent 63%);
}

.math-visual::after {
  inset: 38% 9% 5% 46%;
  background: var(--glow-b);
}

.hero-svg {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
  overflow: visible;
}

.orbit-line {
  fill: none;
  stroke: var(--line-strong);
}

.curve-line {
  fill: none;
  stroke: url(#curve-gradient);
  stroke-width: 2.3;
  stroke-linecap: round;
  stroke-dasharray: 780;
  animation: draw-curve 2s cubic-bezier(.22, .75, .25, 1) both;
}

.curve-glow {
  fill: none;
  stroke: color-mix(in srgb, var(--accent) 20%, transparent);
  stroke-width: 14;
  filter: blur(10px);
}

.node {
  fill: var(--surface);
  stroke: var(--accent);
  stroke-width: 1.7;
  transform-box: fill-box;
  transform-origin: center;
  animation: node-pulse 4s ease-in-out infinite;
}

.node:nth-of-type(2n) { animation-delay: -2s; }

.visual-label {
  fill: var(--text-soft);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 12px;
}

@keyframes draw-curve { from { stroke-dashoffset: 780; } to { stroke-dashoffset: 0; } }
@keyframes node-pulse { 50% { transform: scale(1.28); } }

.stat-strip {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  width: min(calc(100% - 48px), var(--page-width));
  margin: -46px auto 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--bg-elevated);
  box-shadow: var(--shadow);
  backdrop-filter: blur(20px);
}

.stat-item {
  min-width: 0;
  padding: 23px 28px;
}

.stat-item + .stat-item {
  border-left: 1px solid var(--line);
}

.stat-value {
  display: block;
  overflow: hidden;
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: clamp(22px, 3vw, 34px);
  font-weight: 550;
  letter-spacing: -.06em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.stat-label {
  display: block;
  margin-top: 5px;
  color: var(--text-soft);
  font-size: 12px;
}

.content-section {
  padding: 110px 0;
}

.content-section.compact {
  padding: 72px 0;
}

.content-section + .content-section {
  border-top: 1px solid var(--line);
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 28px;
  margin-bottom: 34px;
}

.section-heading h2,
.page-title {
  margin: 0;
  font-size: clamp(30px, 4vw, 48px);
  font-weight: 580;
  letter-spacing: -.055em;
  line-height: 1.08;
}

.section-heading p {
  max-width: 560px;
  margin: 10px 0 0;
  color: var(--text-soft);
  line-height: 1.7;
}

.text-link {
  flex: none;
  color: var(--accent-strong);
  font-size: 13px;
  font-weight: 630;
}

.text-link:hover { text-decoration: underline; text-underline-offset: 4px; }

.story-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.story-card,
.topic-card,
.series-card,
.post-card,
.about-card {
  position: relative;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface) 91%, transparent);
  transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.story-card:hover,
.topic-card:hover,
.series-card:hover,
.post-card:hover {
  border-color: var(--line-strong);
  box-shadow: var(--shadow-tight);
  transform: translateY(-2px);
}

.story-card {
  min-height: 260px;
  padding: 29px;
  overflow: hidden;
  border-radius: var(--radius-lg);
}

.story-index {
  display: block;
  color: var(--accent);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 12px;
}

.story-card h3 {
  margin: 52px 0 10px;
  font-size: 21px;
  font-weight: 590;
  letter-spacing: -.035em;
}

.story-card p {
  margin: 0;
  color: var(--text-soft);
  font-size: 14px;
  line-height: 1.75;
}

.story-formula {
  position: absolute;
  top: 22px;
  right: 25px;
  color: var(--text-faint);
  font-family: Georgia, serif;
  font-size: 20px;
  opacity: .7;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 13px;
}

.topic-card {
  display: flex;
  min-height: 114px;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px;
  padding: 22px;
  border-radius: var(--radius-md);
}

.topic-card h3 {
  margin: 0;
  font-size: 16px;
  font-weight: 580;
}

.topic-card span {
  color: var(--text-faint);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 12px;
}

.series-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 15px;
}

.series-card {
  display: block;
  min-height: 180px;
  padding: 26px;
  border-radius: var(--radius-lg);
}

.card-kicker {
  color: var(--accent-strong);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 11px;
  letter-spacing: .06em;
  text-transform: uppercase;
}

.series-card h3 {
  margin: 28px 0 8px;
  font-size: 21px;
  font-weight: 580;
  letter-spacing: -.035em;
}

.series-meta,
.post-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 7px 13px;
  color: var(--text-faint);
  font-size: 12px;
}

.post-series-link {
  display: inline-flex;
  align-items: center;
  border-bottom: 1px solid color-mix(in srgb, var(--accent) 28%, transparent);
  color: var(--accent-strong);
  font-weight: 600;
  transition: border-color 160ms ease, color 160ms ease;
}

.post-series-link:hover {
  border-color: currentColor;
  color: var(--accent);
}

.post-list {
  display: grid;
  gap: 11px;
}

.post-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 26px;
  padding: 23px 25px;
  border-radius: var(--radius-md);
}

.post-card.is-read {
  border-color: color-mix(in srgb, var(--success) 32%, var(--line));
  box-shadow: inset 3px 0 0 color-mix(in srgb, var(--success) 72%, transparent);
}

.post-card h3 {
  margin: 0 0 11px;
  font-size: 17px;
  font-weight: 590;
  letter-spacing: -.025em;
  line-height: 1.48;
}

.post-summary {
  display: -webkit-box;
  max-width: 850px;
  margin: 13px 0 0;
  overflow: hidden;
  color: var(--text-soft);
  font-size: 13px;
  line-height: 1.7;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.post-summary.is-empty {
  color: var(--text-faint);
  font-size: 12px;
}

.post-card.has-actions .post-summary {
  max-width: 960px;
  -webkit-line-clamp: 3;
}

.post-card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 17px;
}

.post-card-action {
  display: inline-flex;
  min-height: 31px;
  align-items: center;
  padding: 5px 11px;
  border: 1px solid color-mix(in srgb, var(--accent) 28%, var(--line));
  border-radius: 999px;
  color: var(--accent-strong);
  background: var(--accent-soft);
  font-size: 12px;
  font-weight: 620;
  transition: border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.post-card-action:hover {
  border-color: color-mix(in srgb, var(--accent) 50%, var(--line));
  background: color-mix(in srgb, var(--accent-soft) 70%, var(--surface));
  transform: translateY(-1px);
}

.post-card-action.series-action {
  border-color: color-mix(in srgb, var(--violet) 30%, var(--line));
  color: color-mix(in srgb, var(--violet) 82%, var(--text));
  background: color-mix(in srgb, var(--violet) 10%, var(--surface));
}

.post-card-footer {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 14px;
}

.post-card-footer .pill-row {
  flex: 1;
}

.read-status-badge {
  display: inline-flex;
  min-height: 21px;
  align-items: center;
  padding: 2px 7px;
  border: 1px solid color-mix(in srgb, var(--success) 34%, var(--line));
  border-radius: 999px;
  color: var(--success);
  background: color-mix(in srgb, var(--success) 9%, var(--surface));
  font-size: 10px;
  font-weight: 650;
}

.read-status-badge[hidden] {
  display: none;
}

.post-read-toggle {
  flex: none;
  min-height: 29px;
  margin-top: 14px;
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-faint);
  background: transparent;
  cursor: pointer;
  font-size: 11px;
  transition: color 160ms ease, border-color 160ms ease, background 160ms ease;
}

.post-read-toggle:hover,
.post-read-toggle[aria-pressed="true"] {
  border-color: color-mix(in srgb, var(--success) 40%, var(--line));
  color: var(--success);
  background: color-mix(in srgb, var(--success) 8%, var(--surface));
}

.post-arrow {
  align-self: center;
  color: var(--text-faint);
  font-size: 18px;
  transition: color 160ms ease, transform 160ms ease;
}

.post-card:hover .post-arrow {
  color: var(--accent);
  transform: translate(2px, -2px);
}

.pill-row {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 14px;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 25px;
  padding: 3px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-soft);
  background: var(--surface-soft);
  font-size: 11px;
}

.pill.is-filter-link {
  cursor: pointer;
  transition: color 160ms ease, border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.pill.is-filter-link:hover {
  border-color: color-mix(in srgb, var(--accent) 42%, var(--line));
  color: var(--accent-strong);
  background: var(--accent-soft);
  transform: translateY(-1px);
}

.pill.is-tag-link:hover {
  border-color: color-mix(in srgb, var(--violet) 42%, var(--line));
  color: color-mix(in srgb, var(--violet) 82%, var(--text));
  background: color-mix(in srgb, var(--violet) 10%, var(--surface));
}

.page-hero {
  padding: 86px 0 45px;
}

.page-hero .page-title {
  max-width: 850px;
}

.page-description {
  max-width: 650px;
  margin: 18px 0 0;
  color: var(--text-soft);
  font-size: 16px;
  line-height: 1.8;
}

.explore-layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  align-items: start;
  gap: 34px;
  padding-bottom: 100px;
}

.filters-panel {
  position: sticky;
  top: calc(var(--header-height) + 22px);
  display: grid;
  gap: 19px;
}

.filter-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.filter-heading h2 {
  margin: 0;
  font-size: 14px;
}

.filter-close,
.filter-apply {
  display: none;
}

.filter-group {
  display: grid;
  gap: 8px;
}

.filter-label {
  color: var(--text-soft);
  font-size: 12px;
  font-weight: 600;
}

.search-wrap {
  position: relative;
  margin-bottom: 17px;
}

.search-input,
.text-input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  color: var(--text);
  background: var(--surface);
  outline: none;
  transition: border-color 160ms ease, box-shadow 160ms ease;
}

.search-input {
  height: 56px;
  padding: 0 96px 0 48px;
  font-size: 15px;
}

.text-input {
  height: 43px;
  padding: 0 12px;
  font-size: 13px;
}

.search-input:focus,
.text-input:focus {
  border-color: color-mix(in srgb, var(--accent) 65%, var(--line));
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.search-icon {
  position: absolute;
  top: 18px;
  left: 17px;
  color: var(--text-faint);
}

.search-shortcut {
  position: absolute;
  top: 15px;
  right: 14px;
  padding: 4px 7px;
  border: 1px solid var(--line);
  border-radius: 7px;
  color: var(--text-faint);
  background: var(--surface-soft);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 10px;
}

.mobile-filter-button {
  display: none;
}

.select-control {
  position: relative;
}

.select-trigger {
  display: flex;
  width: 100%;
  min-height: 43px;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 8px 11px;
  border: 1px solid var(--line);
  border-radius: 11px;
  color: var(--text);
  background: var(--surface);
  cursor: pointer;
  text-align: left;
  transition: border-color 160ms ease, box-shadow 160ms ease;
}

.select-trigger:hover,
.select-trigger[aria-expanded="true"] {
  border-color: var(--line-strong);
}

.select-trigger[aria-expanded="true"] {
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.select-trigger-text {
  overflow: hidden;
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.select-chevron {
  color: var(--text-faint);
  font-size: 9px;
  transition: transform 160ms ease;
}

.select-trigger[aria-expanded="true"] .select-chevron {
  transform: rotate(180deg);
}

.select-menu {
  position: absolute;
  z-index: 80;
  top: calc(100% + 6px);
  left: 0;
  width: max(100%, 220px);
  max-height: 292px;
  margin: 0;
  padding: 5px;
  overflow: auto;
  border: 1px solid var(--line-strong);
  border-radius: 13px;
  background: var(--surface);
  box-shadow: var(--shadow-tight);
  list-style: none;
  opacity: 0;
  transform: translateY(-5px) scale(.985);
  transform-origin: top;
  visibility: hidden;
  transition: opacity 160ms ease, transform 160ms ease, visibility 160ms;
}

.select-control.is-open .select-menu {
  opacity: 1;
  transform: translateY(0) scale(1);
  visibility: visible;
}

.select-option {
  display: flex;
  min-height: 37px;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 7px 9px;
  border-radius: 8px;
  color: var(--text-soft);
  cursor: pointer;
  font-size: 12px;
  outline: none;
}

.select-option:hover,
.select-option.is-active {
  color: var(--text);
  background: var(--surface-soft);
}

.select-option[aria-selected="true"] {
  color: var(--accent-strong);
  font-weight: 620;
}

.option-check {
  width: 17px;
  color: var(--accent);
  font-size: 12px;
  text-align: center;
}

.more-filters {
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

.more-toggle {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  padding: 0;
  color: var(--text-soft);
  background: transparent;
  cursor: pointer;
  font-size: 12px;
}

.more-filter-content {
  display: none;
  margin-top: 14px;
}

.more-filters.is-open .more-filter-content {
  display: block;
}

.filter-reset {
  padding: 0;
  color: var(--accent-strong);
  background: none;
  cursor: pointer;
  font-size: 11px;
}

.results-toolbar {
  display: flex;
  min-height: 45px;
  align-items: center;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 14px;
}

.result-count {
  color: var(--text-soft);
  font-size: 13px;
}

.results-meta {
  display: flex;
  min-width: 0;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 10px;
}

.result-count strong {
  color: var(--text);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.reading-progress-summary {
  color: var(--text-faint);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 11px;
}

.sort-wrap {
  width: 150px;
}

.results-controls {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
}

.page-size-wrap {
  width: 124px;
}

.page-size-wrap .select-menu {
  right: 0;
  left: auto;
}

.active-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin: 0 0 16px;
}

.filter-chip {
  display: inline-flex;
  min-height: 29px;
  align-items: center;
  gap: 6px;
  padding: 3px 9px 3px 11px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-soft);
  background: var(--surface);
  cursor: pointer;
  font-size: 11px;
}

.filter-chip:hover { border-color: var(--line-strong); }
.filter-chip span:last-child { color: var(--text-faint); font-size: 13px; }

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  margin-top: 32px;
}

.page-button {
  display: grid;
  min-width: 39px;
  height: 39px;
  place-items: center;
  border: 1px solid transparent;
  border-radius: 10px;
  color: var(--text-soft);
  background: transparent;
  cursor: pointer;
  font-size: 12px;
}

.page-button:hover:not(:disabled) {
  border-color: var(--line);
  color: var(--text);
  background: var(--surface);
}

.page-button[aria-current="page"] {
  color: #fff;
  background: #3449c5;
}

.page-button:disabled,
.page-button[aria-disabled="true"] {
  cursor: default;
  opacity: .35;
  pointer-events: none;
}

.topic-summary {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 30px;
  margin-top: 26px;
  color: var(--text-soft);
  font-size: 13px;
}

.topic-summary strong {
  display: block;
  margin-bottom: 3px;
  color: var(--text);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 23px;
}

.timeline {
  position: relative;
  display: grid;
  gap: 0;
  margin-top: 38px;
  padding-left: 40px;
}

.timeline::before {
  position: absolute;
  top: 8px;
  bottom: 22px;
  left: 13px;
  width: 1px;
  background: linear-gradient(var(--accent), var(--line));
  content: "";
}

.timeline-item {
  position: relative;
  padding: 0 0 34px;
}

.timeline-dot {
  position: absolute;
  top: 7px;
  left: -32px;
  display: grid;
  width: 12px;
  height: 12px;
  place-items: center;
  border: 3px solid var(--bg);
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}

.timeline-index {
  margin-bottom: 7px;
  color: var(--accent-strong);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 11px;
}

.timeline-item h3 {
  margin: 0 0 7px;
  font-size: 18px;
  font-weight: 580;
}

.timeline-item h3 a:hover { color: var(--accent-strong); }

.timeline-item.is-read .timeline-dot {
  background: var(--success);
  box-shadow: 0 0 0 1px var(--success);
}

.timeline-actions {
  margin-top: 12px;
}

.timeline-actions .post-read-toggle {
  margin-top: 0;
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}

.about-card {
  padding: 29px;
  border-radius: var(--radius-lg);
}

.about-card h2 {
  margin: 0 0 13px;
  font-size: 19px;
  font-weight: 590;
}

.about-card p,
.about-card li {
  color: var(--text-soft);
  font-size: 14px;
  line-height: 1.8;
}

.about-card p { margin: 0; }
.about-card ul { margin: 0; padding-left: 19px; }

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 40px 0 50px;
  border-top: 1px solid var(--line);
  color: var(--text-faint);
  font-size: 12px;
}

.site-footer-links {
  display: flex;
  gap: 18px;
}

.site-footer a:hover { color: var(--text); }

.drawer-backdrop {
  position: fixed;
  z-index: 190;
  inset: 0;
  background: rgba(2, 5, 12, .52);
  opacity: 0;
  transition: opacity 180ms ease;
}

body.drawer-open .drawer-backdrop {
  opacity: 1;
}

.toast-region {
  position: fixed;
  z-index: 300;
  right: 84px;
  bottom: 22px;
  max-width: min(340px, calc(100vw - 36px));
}

.back-to-top {
  --scroll-progress: 0turn;
  position: fixed;
  z-index: 150;
  right: 22px;
  bottom: 22px;
  display: grid;
  width: 52px;
  height: 52px;
  padding: 3px;
  place-items: center;
  border-radius: 50%;
  color: var(--text);
  background: conic-gradient(var(--accent) var(--scroll-progress), var(--line-strong) 0);
  box-shadow: var(--shadow-tight);
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(10px) scale(.92);
  visibility: hidden;
  transition: opacity 180ms ease, transform 180ms ease, visibility 180ms;
}

.back-to-top::before {
  position: absolute;
  inset: 3px;
  border: 1px solid var(--line);
  border-radius: inherit;
  background: color-mix(in srgb, var(--surface) 94%, transparent);
  backdrop-filter: blur(16px);
  content: "";
}

.back-to-top span {
  position: relative;
  z-index: 1;
  font-size: 21px;
  line-height: 1;
  transition: transform 160ms ease;
}

.back-to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0) scale(1);
  visibility: visible;
}

.back-to-top.is-visible:hover {
  transform: translateY(-2px) scale(1.02);
}

.back-to-top:hover span {
  transform: translateY(-2px);
}

body.drawer-open .back-to-top {
  opacity: 0;
  pointer-events: none;
}

.toast {
  padding: 12px 15px;
  border: 1px solid var(--line-strong);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: var(--shadow-tight);
  font-size: 12px;
}

@media (max-width: 960px) {
  .hero-inner {
    grid-template-columns: 1fr 390px;
    gap: 20px;
  }

  .hero h1 { font-size: clamp(45px, 7vw, 68px); }
  .story-grid, .topic-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  :root { --header-height: 62px; }

  .site-header {
    grid-template-columns: 1fr auto;
    padding: 0 18px;
    background: var(--bg-elevated);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }

  .brand-muted,
  .theme-label { display: none; }

  .main-nav {
    position: fixed;
    z-index: 120;
    right: auto;
    bottom: 14px;
    bottom: max(14px, env(safe-area-inset-bottom));
    left: 50%;
    justify-content: space-around;
    gap: 2px;
    width: calc(100% - 20px);
    width: calc(100% - 20px - env(safe-area-inset-left) - env(safe-area-inset-right));
    max-width: 520px;
    padding: 4px;
    border-color: var(--line-strong);
    border-radius: 17px;
    box-shadow: var(--shadow-tight);
    backdrop-filter: blur(20px);
    transform: translateX(-50%);
  }

  .main-nav a {
    flex: 1;
    min-width: 0;
    padding: 9px 4px;
    font-size: 12px;
    text-align: center;
    white-space: nowrap;
  }

  .header-actions { gap: 6px; }
  .github-link { min-height: 40px; padding: 0 10px; }
  .theme-toggle { min-width: 40px; padding: 0; }
  .page-shell { width: min(calc(100% - 32px), var(--page-width)); }

  .hero {
    min-height: auto;
    overflow: clip;
  }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: 22px;
    width: min(calc(100% - 32px), var(--page-width));
    padding: 52px 0 38px;
  }

  .hero h1 {
    font-size: clamp(34px, 10.3vw, 48px);
    letter-spacing: -.06em;
    line-height: 1.08;
    white-space: pre-line;
  }

  .hero-copy { font-size: 16px; }
  .math-visual {
    position: relative;
    z-index: 0;
    right: auto;
    bottom: auto;
    width: min(76vw, 280px);
    margin: 0 auto;
    opacity: .72;
  }
  .stat-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    width: calc(100% - 32px);
    margin-top: 18px;
  }
  .stat-item { padding: 18px; }
  .stat-item:nth-child(3) { border-left: 0; }
  .stat-item:nth-child(n+3) { border-top: 1px solid var(--line); }
  .content-section { padding: 66px 0; }
  .content-section.compact { padding: 50px 0; }
  .section-heading { align-items: start; flex-direction: column; margin-bottom: 25px; }
  .story-grid, .topic-grid, .series-grid, .about-grid { grid-template-columns: 1fr; }
  .story-card { min-height: 220px; }
  .topic-card { min-height: 94px; }
  .post-card { grid-template-columns: minmax(0, 1fr); gap: 5px; padding: 18px; }
  .post-card-footer { align-items: flex-start; flex-direction: column; gap: 0; }
  .post-read-toggle { margin-top: 10px; }
  .post-arrow { display: none; }
  .page-hero { padding: 63px 0 34px; }

  .explore-layout {
    grid-template-columns: 1fr;
    gap: 0;
    padding-bottom: 100px;
  }

  .search-input { padding-right: 50px; }
  .search-shortcut { display: none; }

  .mobile-filter-button {
    display: inline-flex;
    min-height: 39px;
    align-items: center;
    gap: 6px;
    padding: 0 12px;
    border: 1px solid var(--line);
    border-radius: 10px;
    background: var(--surface);
    cursor: pointer;
    font-size: 12px;
  }

  .filters-panel {
    position: fixed;
    z-index: 200;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    display: grid;
    height: 100vh;
    height: 100dvh;
    max-height: none;
    align-content: start;
    padding: 20px 19px 92px;
    padding: 20px 19px calc(92px + env(safe-area-inset-bottom));
    overflow-x: hidden;
    overflow-y: auto;
    overscroll-behavior: contain;
    border: 0;
    border-radius: 0;
    background: var(--surface);
    box-shadow: var(--shadow);
    opacity: 0;
    pointer-events: none;
    transform: translateY(28px);
    visibility: hidden;
    -webkit-overflow-scrolling: touch;
    transition: opacity 180ms ease, transform 220ms cubic-bezier(.22, .82, .24, 1), visibility 220ms;
  }

  body.drawer-open .filters-panel,
  .filters-panel.is-open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
    visibility: visible;
  }
  .filter-close, .filter-apply { display: inline-flex; }

  .filter-heading {
    position: sticky;
    z-index: 3;
    top: -20px;
    margin: -20px -19px 0;
    padding: 20px 19px 12px;
    padding: max(20px, env(safe-area-inset-top)) 19px 12px;
    border-bottom: 1px solid var(--line);
    background: var(--surface);
    background: color-mix(in srgb, var(--surface) 94%, transparent);
    backdrop-filter: blur(18px);
  }

  .filter-close {
    width: 42px;
    height: 42px;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--surface-soft);
    cursor: pointer;
  }

  .filter-apply {
    position: fixed;
    z-index: 210;
    right: 19px;
    bottom: 18px;
    bottom: max(18px, env(safe-area-inset-bottom));
    left: 19px;
    width: auto;
    margin: 0;
    box-shadow: var(--shadow-tight);
  }

  .select-menu { position: static; display: none; width: 100%; max-height: 220px; margin-top: 5px; box-shadow: none; }
  .select-control.is-open .select-menu { display: block; }
  .results-toolbar { align-items: center; }
  .sort-wrap { width: 134px; }
  .page-size-wrap { width: 124px; }
  .timeline { padding-left: 34px; }
  .timeline-dot { left: -27px; }
  .site-footer { align-items: flex-start; flex-direction: column; padding-bottom: 105px; }
  .site-footer-links { flex-wrap: wrap; }
  .back-to-top {
    right: 18px;
    bottom: calc(84px + env(safe-area-inset-bottom));
    width: 48px;
    height: 48px;
  }
  .toast-region {
    right: 74px;
    bottom: calc(86px + env(safe-area-inset-bottom));
  }
}

@media (max-width: 430px) {
  .github-label { display: none; }
  .github-link { padding: 0 9px; }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .hero-actions .button { width: 100%; }
  .hero-note { line-height: 1.65; }
  .stat-item { padding: 16px 14px; }
  .stat-value { font-size: 23px; }
  .results-toolbar { align-items: stretch; flex-direction: column; gap: 10px; }
  .results-meta { width: 100%; }
  .results-controls {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    width: 100%;
    margin-left: 0;
  }
  .sort-wrap,
  .page-size-wrap { width: 100%; }
  .pagination { gap: 2px; }
  .page-button { min-width: 34px; height: 36px; }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }

  .story-card:hover,
  .topic-card:hover,
  .series-card:hover,
  .post-card:hover,
  .button:hover {
    transform: none;
  }
}