* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.75;
}

::selection {
  background: var(--selection);
}

.material-symbols-outlined {
  font-variation-settings:
    "FILL" 0,
    "wght" 300,
    "GRAD" 0,
    "opsz" 20;
  font-size: 1.05rem;
  line-height: 1;
}

.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;
}

.container {
  width: min(var(--content-width), calc(100vw - 2rem));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--bg);
  background: color-mix(in srgb, var(--bg) 50%, transparent);
  border-bottom: 1px solid color-mix(in srgb, var(--border) 70%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 4.5rem;
  padding: 1rem 0;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  min-width: 0;
  color: inherit;
  text-decoration: none;
}

.logo-mark {
  display: block;
  width: 2rem;
  height: 2rem;
  margin: 0;
  flex: 0 0 auto;
  object-fit: cover;
  border: 1px solid color-mix(in srgb, var(--border) 84%, transparent);
  border-radius: 0.7rem;
}

.logo-copy {
  display: grid;
  gap: 0.08rem;
  min-width: 0;
}

.logo-title {
  color: var(--text);
  font-family: var(--font-heading);
  font-size: 0.96rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.logo-subtitle {
  overflow: hidden;
  color: var(--text-faint);
  font-size: 0.82rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.site-nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  color: var(--text-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  text-decoration: none;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease;
}

.site-nav a:hover {
  border-color: var(--border-strong);
  background: var(--surface-strong);
  color: var(--text);
}

.theme-toggle {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  cursor: pointer;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease;
}

.theme-toggle:hover {
  border-color: var(--border-strong);
  background: var(--surface-strong);
}

.theme-toggle__icon {
  color: var(--text-faint);
  font-size: 1.1rem;
}

.content {
  padding: 3rem 0 4rem;
}

.content > :first-child,
.post-content > :first-child {
  margin-top: 0;
}

h2,
h3,
h4 {
  scroll-margin-top: 6rem;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 2.4rem 0 1rem;
  color: var(--text);
  font-family: var(--font-heading);
  font-weight: 620;
  letter-spacing: -0.03em;
  line-height: 1.22;
}

h1 {
  font-size: clamp(1.72rem, 2.8vw, 2.3rem);
  font-weight: 640;
}

h2 {
  font-size: clamp(1.32rem, 2.1vw, 1.7rem);
  font-weight: 620;
}

h3 {
  font-size: clamp(1.12rem, 1.55vw, 1.28rem);
  font-weight: 600;
}

h4 {
  font-size: clamp(1rem, 1.2vw, 1.08rem);
  font-weight: 580;
}

p,
li,
td,
blockquote {
  color: var(--text-soft);
}

strong,
th {
  color: var(--text);
}

a {
  color: var(--brand);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--brand-strong);
}

ul,
ol {
  padding-left: 1.3rem;
}

li + li {
  margin-top: 0.3rem;
}

blockquote {
  margin: 1.5rem 0;
  padding: 0.15rem 0 0.15rem 1rem;
  border-left: 2px solid var(--border-strong);
}

hr {
  margin: 2.2rem 0;
  border: 0;
  border-top: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
}

.table-wrap {
  margin: 1.5rem 0;
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-small);
  background: var(--surface);
  -webkit-overflow-scrolling: touch;
}

.table-wrap table {
  width: max-content;
  min-width: 100%;
  background: transparent;
}

th,
td {
  padding: 0.8rem 0.95rem;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--border);
  overflow-wrap: anywhere;
}

thead th {
  background: var(--surface-strong);
  white-space: nowrap;
}

table tr > * + * {
  border-left: 1px solid var(--border);
}

tbody tr:last-child td {
  border-bottom: 0;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 1.5rem auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-small);
}

.post-search {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  margin-bottom: 1.2rem;
}

.post-search__label {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--text-faint);
  font-size: 0.88rem;
  font-weight: 500;
}

.post-search__field {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  width: 100%;
  max-width: 36rem;
  min-height: 3rem;
  padding: 0.45rem 0.55rem 0.45rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: calc(var(--radius-small) + 2px);
  background: var(--surface);
  transition: border-color 160ms ease, background-color 160ms ease, box-shadow 160ms ease;
}

.post-search__field:focus-within {
  border-color: var(--border-strong);
  background: var(--surface);
  box-shadow: 0 0 0 4px var(--brand-soft);
}

.post-search__input {
  flex: 1;
  min-width: 0;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 0.96rem;
}

.post-search__input::placeholder {
  color: var(--text-faint);
}

.post-search__input:focus {
  outline: 0;
}

.post-search__clear {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--text-faint);
  cursor: pointer;
  transition: background-color 160ms ease, color 160ms ease;
}

.post-search__clear:hover {
  background: var(--surface-strong);
  color: var(--text);
}

.post-search__clear .material-symbols-outlined {
  font-size: 1.1rem;
}

.category-filter {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.85rem 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.2rem;
}

.category-filter__label {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--text-faint);
  font-size: 0.88rem;
  font-weight: 500;
}

.category-filter__controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.category-filter__button {
  display: inline-flex;
  align-items: center;
  padding: 0.46rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 0.9rem;
  cursor: pointer;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease, transform 160ms ease;
}

.category-filter__button:hover,
.category-filter__button.is-active {
  border-color: var(--border-strong);
  background: var(--brand-soft);
  color: var(--text);
}

.category-filter__button:hover {
  transform: translateY(-1px);
}

.category-filter__button.is-active {
  color: var(--brand-strong);
}

.post-list {
  list-style: none;
  padding: 0;
  margin: 0;
  border-top: 1px solid var(--border);
}

.post-list li[hidden] {
  display: none;
}

.post-list li {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 0.7rem 1.4rem;
  padding: 1.15rem 0.15rem;
  border-bottom: 1px solid var(--border);
  transition: background-color 160ms ease, color 160ms ease;
}

.post-list li:hover {
  background: var(--surface);
}

.post-list__link {
  display: inline-block;
  color: var(--text);
  font-family: var(--font-heading);
  font-size: clamp(1.02rem, 2vw, 1.16rem);
  font-weight: 650;
  letter-spacing: -0.015em;
  text-decoration: none;
  line-height: 1.35;
}

.post-list__link:hover {
  color: var(--brand);
}

.post-list__meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.7rem;
  margin-top: 0;
  color: var(--text-faint);
  font-size: 0.8rem;
}

.post-list__meta .meta-item {
  gap: 0.22rem;
  padding: 0;
  border: 0;
  background: transparent;
  white-space: nowrap;
}

.post-list__meta .meta-icon {
  font-size: 0.88rem;
}

.post-list__meta .meta-tag {
  letter-spacing: 0.01em;
}

.post-list__empty {
  margin: 1rem 0 0;
  color: var(--text-faint);
  font-size: 0.92rem;
}

.post-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 180px;
  gap: 2.5rem;
  align-items: start;
}

.post {
  width: min(100%, 760px);
  min-width: 0;
  margin: 0 auto;
}

.post-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

.post-header h1 {
  margin: 0 0 0.8rem;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.85rem;
  margin: 0;
  color: var(--text-faint);
  font-size: 0.92rem;
}

.meta-item {
  display: inline-flex;
  align-items: center;
  gap: 0.28rem;
}

.meta time,
.meta-tag {
  color: var(--text-soft);
}

.meta-icon {
  color: var(--text-faint);
  font-size: 0.95rem;
}

.post-share {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.7rem 0.85rem;
  margin-top: 1rem;
}

.post-share__label {
  color: var(--text-faint);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.post-share__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.post-share__button {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  min-height: 2.35rem;
  padding: 0.45rem 0.78rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 0.88rem;
  text-decoration: none;
  cursor: pointer;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease;
}

.post-share__button:hover {
  border-color: var(--border-strong);
  background: var(--surface-strong);
  color: var(--text);
}

.post-share__button .material-symbols-outlined {
  font-size: 0.95rem;
}

.post-share__button.is-success {
  border-color: color-mix(in srgb, var(--brand) 45%, var(--border));
  color: var(--brand);
}

.post-share__feedback {
  flex-basis: 100%;
  min-height: 1lh;
  color: var(--text-faint);
  font-size: 0.84rem;
}

.post-share__feedback[data-state="success"] {
  color: var(--brand);
}

.post-content {
  min-width: 0;
  font-size: 1.02rem;
}

/* Keep markdown headings calmer than the global page scale. */
.page-post .post-header h1 {
  font-size: clamp(1.58rem, 2.15vw, 1.98rem);
  font-weight: 630;
  line-height: 1.2;
}

.page-post .post-content h1,
.page-post .post-content h2,
.page-post .post-content h3,
.page-post .post-content h4 {
  line-height: 1.24;
}

.page-post .post-content h1 {
  font-size: clamp(1.52rem, 2.05vw, 1.86rem);
  font-weight: 620;
}

.page-post .post-content h2 {
  font-size: clamp(1.2rem, 1.65vw, 1.42rem);
  font-weight: 600;
}

.page-post .post-content h3 {
  font-size: clamp(1.08rem, 1.32vw, 1.2rem);
  font-weight: 580;
}

.page-post .post-content h4 {
  font-size: clamp(0.98rem, 1.08vw, 1.04rem);
  font-weight: 560;
}

.post-comments {
  margin-top: 3rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--border);
}

.post-comments__header {
  margin-bottom: 1rem;
}

.post-comments__title {
  margin: 0 0 0.35rem;
  font-size: clamp(1.1rem, 2vw, 1.3rem);
}

.post-comments__description {
  margin: 0;
  color: var(--text-faint);
  font-size: 0.92rem;
}

.post-comments .utterances,
.post-comments .utterances-frame {
  max-width: 100%;
}

.post-toc[hidden] {
  display: none;
}

.post-toc {
  position: sticky;
  top: 6rem;
}

.post-toc__title {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-bottom: 0.9rem;
  color: var(--text);
  font-size: 0.88rem;
  font-weight: 600;
}

.post-toc__title .material-symbols-outlined {
  color: var(--text-faint);
  font-size: 1rem;
}

.post-toc__nav {
  border-left: 1px solid var(--border);
  max-height: calc(100vh - 9rem);
  overflow-y: auto;
  padding-left: 0.9rem;
  padding-right: 0.2rem;
  scrollbar-gutter: stable;
}

.post-toc__list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.post-toc__item {
  margin: 0;
}

.post-toc__item + .post-toc__item {
  margin-top: 0.45rem;
}

.post-toc__link {
  display: block;
  color: var(--text-faint);
  font-size: 0.9rem;
  line-height: 1.5;
  text-decoration: none;
}

.post-toc__link:hover {
  color: var(--text);
}

.post-toc__item--h3 .post-toc__link {
  padding-left: 0.75rem;
  font-size: 0.85rem;
}

pre,
code {
  font-family: var(--font-code);
}

p code,
li code,
td code,
blockquote code,
h1 code,
h2 code,
h3 code,
h4 code,
.meta code {
  padding: 0.18rem 0.42rem;
  border: 1px solid var(--border-strong);
  border-radius: 0.45rem;
  background: var(--code-inline-bg);
  color: var(--code-inline-text);
  font-size: 0.92em;
  font-weight: 600;
}

.katex {
  color: var(--text);
}

.katex-display {
  margin: 1.4rem 0;
  overflow-x: auto;
  overflow-y: hidden;
  padding: 0.1rem 0 0.35rem;
}

.katex-display::-webkit-scrollbar {
  height: 0.45rem;
}

.katex-display > .katex {
  min-width: max-content;
}

div.highlighter-rouge,
.mermaid {
  margin: 1.5rem 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-small);
}

div.highlighter-rouge {
  overflow: hidden;
  background: var(--code-bg);
}

div.highlighter-rouge::before {
  content: "Code";
  display: flex;
  align-items: center;
  min-height: 2.35rem;
  padding: 0 0.95rem;
  border-bottom: 1px solid rgba(148, 163, 184, 0.18);
  color: var(--token-comment);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.highlight {
  background: transparent;
}

pre,
pre.highlight {
  margin: 0;
  padding: 1.1rem 1.2rem;
  overflow: auto;
  background: transparent;
  color: var(--code-text);
  font-size: 0.92rem;
  line-height: 1.7;
}

pre code,
.highlight code {
  padding: 0;
  background: transparent;
  color: var(--token-base);
  font-size: inherit;
}

pre::-webkit-scrollbar,
table::-webkit-scrollbar,
.post-toc__nav::-webkit-scrollbar {
  height: 0.65rem;
  width: 0.65rem;
}

pre::-webkit-scrollbar-thumb,
table::-webkit-scrollbar-thumb,
.post-toc__nav::-webkit-scrollbar-thumb {
  background: rgba(148, 163, 184, 0.28);
  border-radius: 999px;
}

.highlight .c,
.highlight .c1,
.highlight .cm,
.highlight .cp,
.highlight .cs {
  color: var(--token-comment);
  font-style: italic;
}

.highlight .k,
.highlight .kc,
.highlight .kd,
.highlight .kn,
.highlight .kp,
.highlight .kr,
.highlight .kt,
.highlight .ow {
  color: var(--token-keyword);
}

.highlight .s,
.highlight .sb,
.highlight .sc,
.highlight .sd,
.highlight .s1,
.highlight .s2,
.highlight .se,
.highlight .sh,
.highlight .si,
.highlight .sr,
.highlight .ss,
.highlight .sx {
  color: var(--token-string);
}

.highlight .na,
.highlight .nf,
.highlight .fm {
  color: var(--token-function);
}

.highlight .nb,
.highlight .bp,
.highlight .no,
.highlight .nv,
.highlight .vc,
.highlight .vg,
.highlight .vi {
  color: var(--token-variable);
}

.highlight .nc,
.highlight .nd,
.highlight .ne,
.highlight .nn,
.highlight .nt {
  color: var(--token-type);
}

.highlight .il,
.highlight .m,
.highlight .mb,
.highlight .mf,
.highlight .mh,
.highlight .mi,
.highlight .mo {
  color: var(--token-number);
}

.highlight .o,
.highlight .p,
.highlight .w {
  color: var(--token-operator);
}

.highlight .err,
.highlight .gd,
.highlight .gi {
  background: transparent;
}

.mermaid {
  overflow: visible;
  padding: 1rem;
  background: var(--surface);
  min-height: 4rem;
  transition: min-height 300ms ease;
  position: relative;
}

.mermaid--loaded {
  min-height: 0;
}

/* ── Zoom controls ── */
.mermaid__zoom-controls {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  display: flex;
  gap: 2px;
  z-index: 10;
  opacity: 0;
  transition: opacity 200ms ease;
  pointer-events: none;
}

.mermaid:hover .mermaid__zoom-controls,
.mermaid:focus-within .mermaid__zoom-controls,
.mermaid--panning .mermaid__zoom-controls {
  opacity: 1;
  pointer-events: auto;
}

.mermaid__zoom-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text-soft);
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
  user-select: none;
  transition: background 150ms ease, color 150ms ease;
}

.mermaid__zoom-btn:hover {
  background: var(--surface-strong);
  color: var(--text);
}

.mermaid__zoom-btn .material-symbols-outlined {
  font-size: 18px;
}

/* ── SVG wrapper ── */
.mermaid__svg-wrap {
  display: flex;
  justify-content: center;
  padding: 8px 16px;
  overflow: hidden;
  cursor: grab;
}

.mermaid__svg-wrap.grabbing {
  cursor: grabbing;
}

.mermaid__svg-wrap svg {
  display: block;
  max-width: 100%;
  height: auto;
  overflow: visible;
  transform-origin: 0 0;
  transition: transform 80ms ease-out;
}

.mermaid__svg-wrap svg * {
  overflow: visible;
}

/* ── Loading skeleton ── */
.mermaid__skeleton {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  padding: 0.5rem 0;
}

.mermaid__skeleton-bar {
  height: 0.85rem;
  border-radius: 6px;
  background: linear-gradient(
    90deg,
    var(--border) 25%,
    var(--surface-strong) 50%,
    var(--border) 75%
  );
  background-size: 200% 100%;
  animation: mermaid-shimmer 1.4s ease-in-out infinite;
}

@keyframes mermaid-shimmer {
  0%   { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ── Error fallback ── */
.mermaid--error {
  min-height: 0;
}

.mermaid__fallback {
  margin: 0;
  white-space: pre-wrap;
  color: var(--text-soft);
  font-family: var(--font-code);
  font-size: 0.85rem;
  line-height: 1.6;
}

.site-footer {
  border-top: 1px solid var(--border);
}

.site-footer .container {
  padding: 1rem 0 2rem;
  color: var(--text-faint);
  font-size: 0.88rem;
}

@media (max-width: 720px) {
  .site-header__inner {
    align-items: center;
    min-height: auto;
    gap: 0.75rem;
  }

  .header-actions {
    width: auto;
    justify-content: flex-end;
    gap: 0.75rem;
  }

  .logo-subtitle {
    display: none;
  }

  .content {
    padding-top: 2rem;
  }
}

@media (max-width: 920px) {
  .post-shell {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .post-toc {
    order: -1;
    position: static;
  }

  .post-toc__nav {
    padding-left: 0;
    padding-right: 0;
    max-height: none;
    overflow: visible;
    border-left: 0;
  }
}

@media (max-width: 560px) {
  .site-header__inner {
    gap: 0.65rem;
    padding: 0.8rem 0;
  }

  .logo {
    gap: 0.45rem;
  }

  .logo-mark {
    width: 1.75rem;
    height: 1.75rem;
    border-radius: 0.6rem;
  }

  .logo-title {
    font-size: 0.92rem;
  }

  .header-actions {
    flex-direction: row;
    align-items: center;
    gap: 0.5rem;
  }

  .site-nav {
    gap: 0.5rem;
    justify-content: flex-start;
  }

  .site-nav a,
  .theme-toggle {
    width: 2.3rem;
    height: 2.3rem;
  }

  .category-filter {
    align-items: flex-start;
  }

  .category-filter__controls {
    width: 100%;
  }

  .theme-toggle {
    justify-content: center;
  }

  .post-share {
    align-items: flex-start;
  }

  .post-share__label,
  .post-share__actions {
    width: 100%;
  }

  .post-list li {
    grid-template-columns: 1fr;
    align-items: start;
    gap: 0.45rem;
    padding: 1rem 0;
  }

  .post-list__meta {
    justify-content: flex-start;
    gap: 0.55rem;
  }
}

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

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}