/* =========================================================================
   Xianbang Wang — personal site + blog hub
   Design system: modern technical / ML-lab. Cool neutrals + indigo accent.
   Geist (sans) + Geist Mono. Light & dark.
   ========================================================================= */

:root {
  /* type */
  --sans: "Geist", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "Geist Mono", ui-monospace, "SF Mono", Menlo, monospace;

  /* fluid scale */
  --step--1: clamp(0.82rem, 0.80rem + 0.10vw, 0.88rem);
  --step-0:  clamp(0.98rem, 0.95rem + 0.15vw, 1.06rem);
  --step-1:  clamp(1.15rem, 1.08rem + 0.35vw, 1.35rem);
  --step-2:  clamp(1.45rem, 1.30rem + 0.70vw, 1.90rem);
  --step-3:  clamp(1.90rem, 1.60rem + 1.40vw, 2.80rem);
  --step-4:  clamp(2.50rem, 2.00rem + 2.60vw, 4.20rem);

  /* spacing rhythm */
  --sp-1: 0.5rem;
  --sp-2: 0.875rem;
  --sp-3: 1.25rem;
  --sp-4: 2rem;
  --sp-5: 3rem;
  --sp-6: 5rem;

  --radius: 14px;
  --radius-sm: 9px;
  --maxw: 1180px;
  --readw: 720px;

  /* accent — indigo (shared across themes, brightness tuned per theme) */
  --accent-h: 268;
}

/* ---- light (default) ---- */
:root, [data-theme="light"] {
  --bg:        oklch(0.992 0.003 264);
  --bg-tint:   oklch(0.975 0.006 264);
  --surface:   oklch(1 0 0);
  --surface-2: oklch(0.982 0.004 264);
  --text:      oklch(0.24 0.018 266);
  --text-soft: oklch(0.40 0.018 266);
  --muted:     oklch(0.56 0.016 266);
  --faint:     oklch(0.72 0.012 266);
  --border:    oklch(0.915 0.006 266);
  --border-2:  oklch(0.86 0.008 266);

  --accent:      oklch(0.55 0.18 var(--accent-h));
  --accent-2:    oklch(0.48 0.17 var(--accent-h));
  --accent-soft: oklch(0.55 0.18 var(--accent-h) / 0.10);
  --accent-line: oklch(0.55 0.18 var(--accent-h) / 0.28);
  --on-accent:   oklch(0.99 0.004 264);

  --shadow-sm: 0 1px 2px oklch(0.24 0.02 266 / 0.05), 0 1px 1px oklch(0.24 0.02 266 / 0.04);
  --shadow-md: 0 4px 14px oklch(0.24 0.02 266 / 0.06), 0 1px 3px oklch(0.24 0.02 266 / 0.05);
  --shadow-lg: 0 18px 40px oklch(0.24 0.04 266 / 0.12), 0 4px 10px oklch(0.24 0.02 266 / 0.06);
  --code-bg:   oklch(0.974 0.005 266);
  color-scheme: light;
}

/* ---- dark ---- */
[data-theme="dark"] {
  --bg:        oklch(0.165 0.012 266);
  --bg-tint:   oklch(0.195 0.014 266);
  --surface:   oklch(0.205 0.015 266);
  --surface-2: oklch(0.235 0.016 266);
  --text:      oklch(0.94 0.008 266);
  --text-soft: oklch(0.80 0.012 266);
  --muted:     oklch(0.66 0.016 266);
  --faint:     oklch(0.52 0.016 266);
  --border:    oklch(0.30 0.016 266);
  --border-2:  oklch(0.37 0.018 266);

  --accent:      oklch(0.74 0.16 var(--accent-h));
  --accent-2:    oklch(0.80 0.13 var(--accent-h));
  --accent-soft: oklch(0.74 0.16 var(--accent-h) / 0.16);
  --accent-line: oklch(0.74 0.16 var(--accent-h) / 0.42);
  --on-accent:   oklch(0.16 0.02 266);

  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.30);
  --shadow-md: 0 6px 20px oklch(0 0 0 / 0.36), 0 1px 3px oklch(0 0 0 / 0.30);
  --shadow-lg: 0 20px 48px oklch(0 0 0 / 0.50), 0 6px 14px oklch(0 0 0 / 0.34);
  --code-bg:   oklch(0.225 0.016 266);
  color-scheme: dark;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  font-family: var(--sans);
  font-size: var(--step-0);
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color .35s ease, color .35s ease;
}

::selection { background: var(--accent-soft); color: var(--text); }

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

h1, h2, h3, h4 {
  line-height: 1.12;
  letter-spacing: -0.02em;
  font-weight: 600;
  margin: 0;
  color: var(--text);
}

p { margin: 0 0 1em; }
img { max-width: 100%; display: block; }

.mono { font-family: var(--mono); }
.muted { color: var(--muted); }

/* shell ----------------------------------------------------------------- */
.wrap { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: clamp(1.1rem, 4vw, 2.5rem); }

/* reading progress ------------------------------------------------------ */
#progress {
  position: fixed; inset: 0 0 auto 0; height: 2px; z-index: 60;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transform-origin: 0 50%; transform: scaleX(0);
  opacity: 0; transition: opacity .25s ease;
}
#progress.on { opacity: 1; }

/* header ---------------------------------------------------------------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(180%) blur(14px);
  background: color-mix(in oklch, var(--bg) 78%, transparent);
  border-bottom: 1px solid transparent;
  transition: border-color .3s ease, background-color .3s ease;
}
.nav.scrolled { border-bottom-color: var(--border); }
.nav__inner { display: flex; align-items: center; gap: var(--sp-3); height: 62px; }

.brand { display: flex; align-items: center; gap: 0.6rem; font-family: var(--mono); font-weight: 500; letter-spacing: -0.01em; cursor: pointer; }
.brand__mark {
  width: 26px; height: 26px; border-radius: 7px; flex: none;
  background: var(--text); color: var(--bg);
  display: grid; place-items: center; font-size: 0.8rem; font-weight: 600;
  transition: transform .3s cubic-bezier(.2,.8,.2,1), background-color .3s ease;
}
.brand:hover .brand__mark { transform: rotate(-8deg) scale(1.05); background: var(--accent); color: var(--on-accent); }
.brand__name { font-size: 0.94rem; }
.brand__dot { color: var(--accent); }

.nav__links { display: flex; gap: 0.35rem; margin-left: auto; }
.nav__link {
  position: relative; padding: 0.45rem 0.7rem; border-radius: 8px;
  font-size: 0.9rem; color: var(--text-soft); cursor: pointer;
  transition: color .2s ease, background-color .2s ease;
}
.nav__link:hover { color: var(--text); background: var(--bg-tint); }
.nav__link.active { color: var(--accent); }
.nav__link.active::after {
  content: ""; position: absolute; left: 0.7rem; right: 0.7rem; bottom: 0.18rem;
  height: 2px; border-radius: 2px; background: var(--accent);
}

.icon-btn {
  width: 38px; height: 38px; flex: none; border-radius: 9px; cursor: pointer;
  display: grid; place-items: center; color: var(--text-soft);
  background: transparent; border: 1px solid var(--border);
  transition: background-color .2s ease, color .2s ease, border-color .2s ease;
}
.icon-btn:hover { background: var(--bg-tint); color: var(--text); border-color: var(--border-2); }
.icon-btn svg { width: 18px; height: 18px; }

/* buttons / chips ------------------------------------------------------- */
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.6rem 0.95rem; border-radius: 10px;
  font-size: 0.9rem; font-weight: 500; cursor: pointer;
  border: 1px solid var(--border-2); background: var(--surface); color: var(--text);
  transition: transform .15s ease, box-shadow .2s ease, border-color .2s ease, background-color .2s ease;
}
.btn svg { width: 16px; height: 16px; }
.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow-sm); border-color: var(--accent-line); }
.btn--accent { background: var(--accent); color: var(--on-accent); border-color: transparent; }
.btn--accent:hover { box-shadow: var(--shadow-md); }
.btn--ghost { background: transparent; }

.chip {
  display: inline-flex; align-items: center; gap: 0.4rem;
  padding: 0.28rem 0.6rem; border-radius: 999px;
  font-family: var(--mono); font-size: 0.76rem; letter-spacing: -0.01em;
  color: var(--text-soft); background: var(--bg-tint); border: 1px solid var(--border);
  cursor: pointer; transition: all .18s ease; white-space: nowrap;
}
.chip:hover { color: var(--text); border-color: var(--border-2); }
.chip.on { background: var(--accent); color: var(--on-accent); border-color: transparent; }

.eyebrow {
  font-family: var(--mono); font-size: 0.76rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--accent); font-weight: 500;
  display: inline-flex; align-items: center; gap: 0.5rem;
}
.eyebrow::before { content: ""; width: 1.6rem; height: 1px; background: var(--accent-line); }

/* section heads */
.sec-head { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; margin-bottom: var(--sp-4); }
.sec-head h2 { font-size: var(--step-2); }
.sec-link { font-size: 0.88rem; color: var(--muted); display: inline-flex; align-items: center; gap: 0.3rem; transition: color .2s, gap .2s; }
.sec-link:hover { color: var(--accent); gap: 0.55rem; }

.view { opacity: 1; }
@keyframes fade { from { transform: translateY(10px); } to { transform: none; } }
@media (prefers-reduced-motion: no-preference) { .view { animation: fade .4s ease; } }

/* ===================== HERO ===================== */
.hero { padding-top: clamp(2.5rem, 6vw, 5rem); padding-bottom: clamp(2rem, 4vw, 3.5rem); }
.hero__grid { display: grid; grid-template-columns: 1fr 300px; gap: clamp(2rem, 5vw, 4.5rem); align-items: center; }
.hero__name { font-size: var(--step-4); font-weight: 600; letter-spacing: -0.035em; margin-bottom: 0.2em; }
.hero__name .grad {
  background: linear-gradient(105deg, var(--accent), var(--accent-2) 60%, var(--text));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero__role { font-size: var(--step-1); color: var(--text-soft); font-weight: 450; margin-bottom: 1.1rem; }
.hero__role b { color: var(--text); font-weight: 600; }
.hero__bio { font-size: var(--step-0); color: var(--text-soft); max-width: 56ch; margin-bottom: 1.5rem; }
.hero__bio a { color: var(--accent); border-bottom: 1px solid var(--accent-line); padding-bottom: 1px; }
.hero__bio a:hover { border-color: var(--accent); }

.hero__links { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-bottom: 1.4rem; }
.cred { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.hero__photo { position: relative; justify-self: center; }
.hero__photo img {
  width: 248px; height: 248px; object-fit: cover; object-position: center top;
  border-radius: 20px; border: 1px solid var(--border); box-shadow: var(--shadow-lg);
}
.hero__photo::before {
  content: ""; position: absolute; inset: -14px -14px auto auto; width: 120px; height: 120px;
  background: radial-gradient(circle at 70% 30%, var(--accent-soft), transparent 70%);
  filter: blur(8px); z-index: -1;
}
/* ===================== PUBLICATIONS ===================== */
section.block { padding-block: clamp(2.5rem, 5vw, 4rem); }
.divider { border: 0; border-top: 1px solid var(--border); margin: 0; }

.pub-list { display: grid; gap: var(--sp-3); }
.pub {
  display: grid; grid-template-columns: 168px 1fr; gap: var(--sp-3);
  padding: var(--sp-3); border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--surface); transition: transform .2s ease, box-shadow .25s ease, border-color .2s ease;
}
.pub:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); border-color: var(--border-2); }
.pub__media { border-radius: var(--radius-sm); overflow: hidden; border: 1px solid var(--border); background: var(--bg-tint); aspect-ratio: 16/10; }
.pub__media img { width: 100%; height: 100%; object-fit: cover; transition: transform .4s ease; }
.pub:hover .pub__media img { transform: scale(1.04); }
.pub__venue { align-self: start; }
.venue {
  font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.02em;
  padding: 0.18rem 0.5rem; border-radius: 6px; border: 1px solid var(--accent-line);
  color: var(--accent); background: var(--accent-soft);
}
.pub__title { font-size: var(--step-1); margin: 0.5rem 0 0.4rem; letter-spacing: -0.02em; }
.pub__title a { background: linear-gradient(var(--accent), var(--accent)) 0 100% / 0 1px no-repeat; transition: background-size .3s ease, color .2s; }
.pub:hover .pub__title a { color: var(--accent); }
.pub__authors { font-size: 0.88rem; color: var(--muted); margin-bottom: 0.7rem; }
.pub__authors b { color: var(--text); }
.pub__links { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.linklet { display: inline-flex; align-items: center; gap: 0.32rem; font-family: var(--mono); font-size: 0.78rem; color: var(--text-soft); padding: 0.3rem 0.55rem; border-radius: 7px; border: 1px solid var(--border); transition: all .18s; }
.linklet:hover { color: var(--accent); border-color: var(--accent-line); background: var(--accent-soft); }
.linklet svg { width: 13px; height: 13px; }

/* ===================== POST LIST ===================== */
.posts { display: grid; gap: 0; }
.post-row {
  display: grid; grid-template-columns: 120px 1fr auto; gap: var(--sp-3); align-items: center;
  padding: var(--sp-3) 0.5rem; border-bottom: 1px solid var(--border); cursor: pointer;
  transition: background-color .2s ease, padding-left .25s ease;
}
.post-row:first-child { border-top: 1px solid var(--border); }
.post-row:hover { background: var(--surface-2); padding-left: 1rem; }
.post-row__date { font-family: var(--mono); font-size: 0.78rem; color: var(--muted); }
.post-row__main { min-width: 0; }
.post-row__type { font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.04em; text-transform: uppercase; color: var(--accent); }
.post-row__type.pub-type { color: oklch(0.62 0.15 200); }
[data-theme="dark"] .post-row__type.pub-type { color: oklch(0.74 0.13 200); }
.post-row__title { font-size: var(--step-1); font-weight: 550; margin: 0.15rem 0; letter-spacing: -0.02em; transition: color .2s; }
.post-row:hover .post-row__title { color: var(--accent); }
.post-row__tags { display: flex; gap: 0.4rem; flex-wrap: wrap; margin-top: 0.35rem; }
.post-row__arrow { color: var(--faint); transition: transform .25s ease, color .2s; }
.post-row:hover .post-row__arrow { transform: translateX(4px); color: var(--accent); }

/* card grid for blog index */
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(330px, 1fr)); gap: var(--sp-3); }
.pcard {
  display: flex; flex-direction: column; border: 1px solid var(--border); border-radius: var(--radius);
  overflow: hidden; background: var(--surface); cursor: pointer;
  transition: transform .2s ease, box-shadow .25s ease, border-color .2s ease;
}
.pcard:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--border-2); }
.pcard__media { aspect-ratio: 16/9; background: var(--bg-tint); border-bottom: 1px solid var(--border); overflow: hidden; }
.pcard__media img { width: 100%; height: 100%; object-fit: cover; transition: transform .4s ease; }
.pcard:hover .pcard__media img { transform: scale(1.05); }
.pcard__body { padding: var(--sp-3); display: flex; flex-direction: column; gap: 0.5rem; flex: 1; }
.pcard__top { display: flex; justify-content: space-between; align-items: center; font-family: var(--mono); font-size: 0.72rem; }
.pcard__top .t { color: var(--accent); letter-spacing: 0.04em; text-transform: uppercase; }
.pcard__top .d { color: var(--muted); }
.pcard__title { font-size: var(--step-1); letter-spacing: -0.02em; margin-bottom: 0.1rem; }
.pcard:hover .pcard__title { color: var(--accent); }
.pcard__blurb { font-size: 0.88rem; color: var(--muted); flex: 1; }
.pcard__tags { display: flex; gap: 0.4rem; flex-wrap: wrap; }

/* placeholder media */
.ph {
  width: 100%; height: 100%; display: grid; place-items: center;
  background-image: repeating-linear-gradient(135deg, var(--border) 0 1px, transparent 1px 10px);
  color: var(--faint); font-family: var(--mono); font-size: 0.72rem;
}

/* ===================== ARTICLE / POST VIEW ===================== */
.article-shell { display: grid; grid-template-columns: 1fr minmax(0, var(--readw)) 1fr; gap: var(--sp-4); padding-top: var(--sp-4); }
.article-toc { position: sticky; top: 90px; align-self: start; max-height: calc(100vh - 120px); overflow: auto; padding-right: 0.5rem; }
.article-main { min-width: 0; }
.article-aside-r {}

.toc-label { font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); margin-bottom: 0.8rem; }
.toc { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--border); }
.toc li a {
  display: block; padding: 0.3rem 0 0.3rem 0.9rem; margin-left: -1px;
  border-left: 2px solid transparent; font-size: 0.83rem; color: var(--muted);
  line-height: 1.4; transition: color .2s, border-color .2s;
}
.toc li a:hover { color: var(--text); }
.toc li a.active { color: var(--accent); border-left-color: var(--accent); font-weight: 500; }
.toc li.sub a { padding-left: 1.7rem; font-size: 0.8rem; }

.back-link { display: inline-flex; align-items: center; gap: 0.4rem; font-size: 0.85rem; color: var(--muted); margin-bottom: 1.5rem; transition: gap .2s, color .2s; }
.back-link:hover { color: var(--accent); gap: 0.65rem; }

.article-head { margin-bottom: var(--sp-4); }
.article-head h1 { font-size: var(--step-3); letter-spacing: -0.03em; margin: 0.6rem 0 0.8rem; max-width: 22ch; }
.article-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem 0.9rem; font-family: var(--mono); font-size: 0.8rem; color: var(--muted); }
.article-meta > span:not(.dot) { white-space: nowrap; }
.article-meta .dot { width: 3px; height: 3px; border-radius: 50%; background: var(--faint); }
.article-authors { font-size: 0.92rem; color: var(--text-soft); margin-top: 0.9rem; }
.article-authors b { color: var(--text); }

/* prose */
.prose { font-size: 1.04rem; line-height: 1.75; color: var(--text-soft); }
.prose > * + * { margin-top: 1.1em; }
.prose h2 { font-size: var(--step-2); color: var(--text); margin-top: 2.2em; margin-bottom: 0.1em; scroll-margin-top: 86px; letter-spacing: -0.025em; }
.prose h2 .hn { font-family: var(--mono); font-size: 0.6em; color: var(--accent); margin-right: 0.6rem; font-weight: 500; }
.prose h3 { font-size: var(--step-1); color: var(--text); margin-top: 1.6em; scroll-margin-top: 86px; }
.prose strong { color: var(--text); font-weight: 600; }
.prose a { color: var(--accent); border-bottom: 1px solid var(--accent-line); }
.prose ul, .prose ol { padding-left: 1.3rem; }
.prose li { margin: 0.4em 0; }
.prose li::marker { color: var(--accent); }
.prose blockquote {
  margin: 1.4em 0; padding: 0.6rem 1.1rem; border-left: 3px solid var(--accent);
  background: var(--accent-soft); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-soft); font-style: normal;
}
.prose blockquote p { margin: 0; }
.prose figure { margin: 1.6em 0; }
.prose figure img { border-radius: var(--radius-sm); border: 1px solid var(--border); background: var(--surface); padding: 0.5rem; }
.prose figcaption { font-size: 0.82rem; color: var(--muted); text-align: center; margin-top: 0.6rem; font-family: var(--mono); }
.sample-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 0.75rem; margin: 1.4em 0;
}
.sample-card {
  border: 1px solid var(--border); border-radius: var(--radius-sm); overflow: hidden;
  background: var(--surface);
}
.sample-card img { width: 100%; aspect-ratio: 1 / 1; object-fit: cover; display: block; }
.sample-card span {
  display: block; padding: 0.45rem 0.55rem; font-family: var(--mono);
  font-size: 0.72rem; color: var(--muted); line-height: 1.35;
}
.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--radius-sm); background: var(--surface); }
.mini-table { width: 100%; border-collapse: collapse; min-width: 560px; font-size: 0.9rem; color: var(--text-soft); }
.mini-table th, .mini-table td { padding: 0.65rem 0.75rem; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
.mini-table th { font-family: var(--mono); font-size: 0.76rem; color: var(--text); background: var(--bg-tint); font-weight: 600; }
.mini-table tr:last-child td { border-bottom: 0; }
.mini-table td.num, .mini-table th.num { text-align: right; white-space: nowrap; }
.mini-table .ours td { color: var(--text); font-weight: 550; }
.table-note { margin-top: 0.55rem; font-family: var(--mono); font-size: 0.78rem; color: var(--muted); }
.refs { font-size: 0.92rem; }
.refs li { padding-left: 0.2rem; }

.callout {
  display: flex; gap: 0.75rem; padding: 0.9rem 1.1rem; border-radius: var(--radius-sm);
  border: 1px solid var(--border-2); background: var(--surface-2); font-size: 0.95rem;
}
.callout svg { width: 18px; height: 18px; flex: none; color: var(--accent); margin-top: 2px; }

/* code */
.prose pre {
  background: var(--code-bg); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 1rem 1.1rem; overflow-x: auto; font-family: var(--mono); font-size: 0.86rem;
  line-height: 1.6; position: relative;
}
.prose pre code { font-family: var(--mono); background: none; padding: 0; }
.prose :not(pre) > code {
  font-family: var(--mono); font-size: 0.86em; padding: 0.12em 0.4em; border-radius: 5px;
  background: var(--code-bg); border: 1px solid var(--border); color: var(--accent-2);
}
[data-theme="dark"] .prose :not(pre) > code { color: var(--accent-2); }
.code-head {
  display: flex; align-items: center; justify-content: space-between;
  font-family: var(--mono); font-size: 0.74rem; color: var(--muted);
  background: var(--surface-2); border: 1px solid var(--border); border-bottom: 0;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0; padding: 0.45rem 0.8rem;
}
.code-head + pre { border-radius: 0 0 var(--radius-sm) var(--radius-sm); }
.copy-btn { cursor: pointer; color: var(--muted); display: inline-flex; gap: 0.3rem; align-items: center; transition: color .2s; }
.copy-btn:hover { color: var(--accent); }
.copy-btn svg { width: 13px; height: 13px; }

.katex-display { overflow-x: auto; overflow-y: hidden; padding: 0.4em 0; }

/* article footer / nav */
.article-foot { margin-top: var(--sp-5); padding-top: var(--sp-4); border-top: 1px solid var(--border); display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }

/* ===================== FOOTER ===================== */
.foot { border-top: 1px solid var(--border); margin-top: var(--sp-6); padding-block: var(--sp-4); }
.foot__inner { display: flex; justify-content: space-between; align-items: center; gap: 1rem; flex-wrap: wrap; }
.foot__meta { font-family: var(--mono); font-size: 0.78rem; color: var(--muted); }
.foot__links { display: flex; gap: 0.4rem; }

/* page header (blog index / generic) */
.page-head { padding-top: clamp(2.5rem, 6vw, 4.5rem); padding-bottom: var(--sp-4); }
.page-head h1 { font-size: var(--step-3); letter-spacing: -0.03em; margin: 0.5rem 0 0.6rem; }
.page-head p { color: var(--text-soft); max-width: 60ch; font-size: var(--step-0); }
.filter-bar { display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center; margin-top: var(--sp-3); }
.filter-bar .lbl { font-family: var(--mono); font-size: 0.74rem; color: var(--muted); margin-right: 0.3rem; }

/* not found */
.notfound {
  min-height: calc(100vh - 62px - 140px);
  display: flex; flex-direction: column; justify-content: center;
  padding-top: var(--sp-6); padding-bottom: var(--sp-6);
}
.notfound h1 {
  font-size: var(--step-4); letter-spacing: -0.035em;
  max-width: 11ch; margin: 0.5rem 0 1rem;
}
.notfound p {
  max-width: 54ch; color: var(--text-soft);
  font-size: var(--step-0); margin-bottom: 1rem;
}
.notfound__path {
  display: inline-block; width: fit-content; max-width: 100%;
  overflow-wrap: anywhere; font-family: var(--mono);
  font-size: 0.82rem !important; color: var(--muted) !important;
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 0.45rem 0.65rem; background: var(--surface);
}
.notfound__actions { display: flex; flex-wrap: wrap; gap: 0.65rem; margin-top: 0.4rem; }

/* easter-egg overlay */
.egg {
  position: fixed; inset: 0; z-index: 100; display: grid; place-items: center;
  background: color-mix(in oklch, var(--bg) 70%, transparent); backdrop-filter: blur(8px);
  animation: fade .3s ease both;
}
.egg__card {
  background: var(--surface); border: 1px solid var(--border-2); border-radius: var(--radius);
  padding: 2rem 2.4rem; box-shadow: var(--shadow-lg); text-align: center; max-width: 380px;
  animation: pop .4s cubic-bezier(.2,.9,.3,1.3) both;
}
@keyframes pop { from { transform: scale(.9); opacity: 0; } to { transform: none; opacity: 1; } }
.egg__card .zen { font-size: 2.6rem; margin-bottom: 0.6rem; }
.egg__card h3 { font-size: var(--step-1); margin-bottom: 0.5rem; }
.egg__card p { color: var(--muted); font-size: 0.9rem; margin: 0; }
.egg__hint { font-family: var(--mono); font-size: 0.74rem; color: var(--faint); margin-top: 1.5rem; }
.egg__hint kbd { background: var(--bg-tint); border: 1px solid var(--border); border-radius: 5px; padding: 0.1em 0.4em; color: var(--text-soft); }

/* responsive ------------------------------------------------------------ */
@media (max-width: 1080px) {
  .article-shell { grid-template-columns: 220px 1fr; }
  .article-aside-r { display: none; }
}
@media (max-width: 860px) {
  .hero__grid { grid-template-columns: 1fr; gap: 2rem; }
  .hero__photo { justify-self: start; }
  .hero__photo img { width: 150px; height: 150px; }
  .pub { grid-template-columns: 1fr; }
  .pub__media { aspect-ratio: 16/8; max-height: 200px; }
  .article-shell { grid-template-columns: 1fr; }
  .article-toc { display: none; }
  .nav__links { display: none; }
}
@media (max-width: 560px) {
  .post-row { grid-template-columns: 1fr auto; }
  .post-row__date { display: none; }
}

/* tag-filter hidden state */
.hide { display: none !important; }