@import url('https://fonts.googleapis.com/css2?family=Space+Mono:wght@400;700&display=swap');

:root {
  --ink: #000000;
  --paper: #ffffff;
  --dim: #f1f1f1;
  --line: 2px solid #000000;
  --gut: 1.25rem;
  --maxw: 1180px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 132px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Space Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 1.03rem;
  line-height: 1.7;
  letter-spacing: 0.005em;
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: inherit;
}

h1,
h2,
h3 {
  margin: 0 0 0.6em;
  line-height: 1.18;
  letter-spacing: -0.012em;
}

h1 {
  font-size: clamp(1.85rem, 5.2vw, 3.4rem);
  font-weight: 700;
}

h2 {
  font-size: clamp(1.32rem, 2.5vw, 1.85rem);
  font-weight: 700;
}

h3 {
  font-size: 1.1rem;
  font-weight: 700;
}

p {
  margin: 0 0 1.1em;
}

:focus-visible {
  outline: 3px solid #000000;
  outline-offset: 2px;
}

/* ---------- 站头 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--paper);
  border-bottom: var(--line);
}

.brand-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0.5rem var(--gut);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  min-height: 42px;
  padding: 0.45rem 0;
  font-weight: 700;
  font-size: 1.02rem;
  text-decoration: none;
}

.brand i {
  display: block;
  width: 14px;
  height: 14px;
  background: var(--ink);
}

.contact {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0.5rem 0.9rem;
  border: 2px solid var(--ink);
  background: var(--ink);
  color: var(--paper);
  font-size: 0.95rem;
  text-decoration: none;
}

.contact:hover {
  background: var(--paper);
  color: var(--ink);
}

.anchor-bar {
  background: var(--ink);
  border-top: var(--line);
}

.anchor-bar p {
  display: flex;
  gap: 0 0.1rem;
  margin: 0 auto;
  max-width: var(--maxw);
  padding: 0 calc(var(--gut) - 0.35rem);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.anchor-bar a {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0.55rem 0.55rem;
  color: var(--paper);
  font-size: 0.95rem;
  text-decoration: none;
  white-space: nowrap;
}

.anchor-bar a:hover,
.anchor-bar a:focus-visible {
  background: var(--paper);
  color: var(--ink);
}

/* ---------- 首屏 ---------- */

.hero {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 70vh;
  padding: 3rem var(--gut) 4rem;
  overflow: hidden;
  background: var(--ink);
  color: var(--paper);
  text-align: center;
}

.hero-frame {
  position: absolute;
  inset: 0;
  margin: 0;
}

.hero-media {
  position: absolute;
  inset: 0;
}

.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.12);
}

.hero-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.82));
}

.hero-frame figcaption {
  position: absolute;
  left: var(--gut);
  bottom: 1.1rem;
  z-index: 3;
  padding: 0.35rem 0.7rem;
  background: var(--paper);
  color: var(--ink);
  font-size: 0.85rem;
  letter-spacing: 0.14em;
}

.hero-copy {
  position: relative;
  z-index: 2;
  max-width: 46rem;
}

.hero-copy h1 {
  margin-bottom: 0.8em;
}

.hero-lead {
  margin-bottom: 1.7rem;
  color: #e8e8e8;
  font-size: 1rem;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.7rem 1.3rem;
  border: 2px solid var(--paper);
  background: var(--paper);
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}

.hero-cta:hover {
  background: transparent;
  color: var(--paper);
}

/* ---------- 正文网格 ---------- */

.content-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 0 1rem;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 2.5rem var(--gut) 4rem;
}

.prose {
  grid-column: 1 / -1;
  min-width: 0;
  counter-reset: blk;
}

.rail {
  grid-column: 1 / -1;
  margin-top: 2.5rem;
  border: var(--line);
  background: var(--dim);
  padding: 1.2rem 1.1rem 1.4rem;
}

.prose > h2 {
  padding-bottom: 0.45rem;
  border-bottom: var(--line);
  margin-bottom: 1.4rem;
}

.prose > h2 span {
  border-bottom: 3px solid #000000;
  padding-bottom: 0.15rem;
}

.prose section[id] {
  counter-increment: blk;
  border-top: var(--line);
  padding: 2.2rem 0 0.6rem;
  scroll-margin-top: 132px;
}

.prose section[id]:first-of-type {
  border-top: 0;
  padding-top: 0.4rem;
}

.prose section[id]::before {
  content: "0" counter(blk);
  display: block;
  margin-bottom: 0.55rem;
  font-size: 0.9rem;
  letter-spacing: 0.2em;
}

.prose h2 span,
.prose h3 span {
  display: inline-block;
}

.prose h2 {
  padding-bottom: 0.4rem;
  border-bottom: 1px solid #000000;
}

.prose h2 span {
  border-bottom: 3px solid #000000;
  padding-bottom: 0.12rem;
}

.prose h3 {
  margin-top: 1.6em;
}

.prose ul,
.prose ol {
  margin: 0 0 1.2em;
  padding-left: 1.35em;
}

.prose li {
  margin-bottom: 0.45em;
}

.prose a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose blockquote {
  margin: 0 0 1.2em;
  padding: 0.9rem 1.1rem;
  border-left: 6px solid #000000;
  background: var(--dim);
}

.prose blockquote p:last-child {
  margin-bottom: 0;
}

.prose figure {
  margin: 0 0 1.4em;
}

.prose figcaption {
  padding-top: 0.5rem;
  font-size: 0.9rem;
  color: #333333;
}

.prose img {
  width: 100%;
  height: auto;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.4em;
  font-size: 0.95rem;
}

.prose th,
.prose td {
  border: 1px solid #000000;
  padding: 0.55rem 0.7rem;
  text-align: left;
  vertical-align: top;
}

.prose th {
  background: var(--ink);
  color: var(--paper);
}

.prose code {
  padding: 0.1em 0.3em;
  background: var(--dim);
}

/* ---------- 侧栏 ---------- */

.rail h2 {
  margin-bottom: 0.9rem;
  padding-bottom: 0.5rem;
  border-bottom: var(--line);
  font-size: 1rem;
  letter-spacing: 0.08em;
}

.rail ol {
  counter-reset: rail;
  margin: 0 0 1.1rem;
  padding: 0;
  list-style: none;
}

.rail li {
  counter-increment: rail;
  border-top: 1px solid #000000;
}

.rail li:first-child {
  border-top: 0;
}

.rail li a {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  min-height: 42px;
  padding: 0.45rem 0;
  font-size: 0.95rem;
  text-decoration: none;
}

.rail li a::before {
  content: "0" counter(rail);
  font-size: 0.78rem;
  letter-spacing: 0.1em;
}

.rail li a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.rail-note {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.6;
}

/* ---------- 页脚 ---------- */

.site-footer {
  border-top: var(--line);
  background: var(--ink);
  color: var(--paper);
  padding: 1.7rem var(--gut);
}

.f-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem 1.5rem;
  max-width: var(--maxw);
  margin: 0 auto;
}

.f-brand {
  font-size: clamp(1.4rem, 3.6vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.f-brand a {
  text-decoration: none;
}

.f-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0 1rem;
}

.f-nav a {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0.35rem 0;
  font-size: 0.95rem;
  text-decoration: none;
}

.f-nav a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.f-copy {
  font-size: 0.9rem;
  color: #d8d8d8;
}

/* ---------- 动效 ---------- */

@media (prefers-reduced-motion: no-preference) {
  .reveal-on [data-reveal] {
    opacity: 0;
    transform: translateY(14px);
    transition: opacity 0.55s ease, transform 0.55s ease;
  }

  .reveal-on [data-reveal].is-in {
    opacity: 1;
    transform: none;
  }
}

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

/* ---------- 断点 ---------- */

@media (min-width: 640px) {
  .prose {
    padding-right: 0.5rem;
  }
}

@media (min-width: 900px) {
  :root {
    --gut: 2rem;
  }

  .hero {
    padding: 4rem var(--gut) 5rem;
  }

  .content-grid {
    padding-top: 3.5rem;
    gap: 0 1.5rem;
  }

  .prose {
    grid-column: 1 / span 8;
  }

  .rail {
    grid-column: 10 / span 3;
    margin-top: 0;
    position: sticky;
    top: 128px;
    align-self: start;
  }

  .f-inner {
    flex-wrap: nowrap;
  }
}

@media (max-width: 420px) {
  .hero-frame figcaption {
    bottom: 0.8rem;
    font-size: 0.8rem;
    letter-spacing: 0.1em;
  }

  .anchor-bar a {
    font-size: 0.9rem;
  }
}

button[aria-expanded]{min-width:44px;min-height:44px}