@import url('https://fonts.googleapis.com/css2?family=Nunito+Sans:wght@300;400;600;700;900&family=Varela+Round&display=swap');

:root {
  --ink: #000000;
  --paper: #ffffff;
  --mute: #6d6d6d;
  --line: #e3e3e3;
  --radius: 10px;
  --gut: clamp(1.15rem, 5vw, 4.5rem);
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: 'Nunito Sans', ui-sans-serif, system-ui, -apple-system, 'Segoe UI', sans-serif;
  font-size: 1.0625rem;
  line-height: 1.66;
  overflow-x: hidden;
  font-weight: 400;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 900;
  line-height: 1.02;
  letter-spacing: -0.03em;
  overflow-wrap: break-word;
}

p {
  margin: 0 0 1.1rem;
}

a {
  color: var(--ink);
}

img {
  max-width: 100%;
}

hr {
  border: 0;
  height: 3px;
  background: var(--ink);
  margin: 0 0 1.25rem;
}

/* ---------- 顶部 ---------- */

.top {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.menu-toggle {
  position: absolute;
  top: 0;
  left: 0;
  width: 1px;
  height: 1px;
  opacity: 0;
  margin: 0;
}

.ticker {
  margin: 0;
  background: var(--ink);
  color: var(--paper);
  font-size: 0.8rem;
  letter-spacing: 0.22em;
  padding: 0.45rem var(--gut);
  word-break: break-word;
}

.brandrow {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem var(--gut);
}

.brand {
  font-family: 'Varela Round', 'Nunito Sans', system-ui, sans-serif;
  font-size: clamp(1.35rem, 4vw, 1.9rem);
  letter-spacing: 0.01em;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.burger {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  min-height: 44px;
  padding: 0.3rem 0 0.3rem 0.2rem;
  cursor: pointer;
  font-size: 0.95rem;
  letter-spacing: 0.12em;
  user-select: none;
}

.bars {
  display: inline-block;
  width: 22px;
  height: 12px;
  position: relative;
}

.bars span {
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--ink);
}

.bars span:first-child {
  top: 0;
}

.bars span:last-child {
  bottom: 0;
}

.site-nav {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1rem;
  padding: clamp(1.6rem, 8vw, 6rem);
  background: var(--ink);
  color: var(--paper);
  transform: translateY(-102%);
  visibility: hidden;
  transition: transform 0.5s cubic-bezier(0.2, 0.9, 0.2, 1), visibility 0.5s;
  overflow-y: auto;
}

.menu-toggle:checked ~ .site-nav {
  transform: none;
  visibility: visible;
}

.nav-close {
  align-self: flex-start;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.35rem 1.1rem;
  border: 2px solid var(--paper);
  border-radius: var(--radius);
  color: var(--paper);
  font-size: 0.95rem;
  letter-spacing: 0.14em;
  cursor: pointer;
  margin-bottom: 1.4rem;
}

.site-nav p {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem 1.6rem;
  margin: 0;
}

.site-nav a {
  color: var(--paper);
  text-decoration: none;
  font-family: 'Varela Round', 'Nunito Sans', system-ui, sans-serif;
  font-size: clamp(1.5rem, 5.6vw, 3rem);
  line-height: 1.25;
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 0.25rem 0;
  border-bottom: 3px solid transparent;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  border-bottom-color: var(--paper);
}

/* ---------- 首屏 ---------- */

.hero {
  position: relative;
  overflow: hidden;
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  align-content: center;
  gap: clamp(1.6rem, 4vw, 3rem);
  padding: clamp(1.6rem, 6vw, 4rem) var(--gut) clamp(3rem, 8vw, 6rem);
}

.hero::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: clamp(18px, 3vw, 42px);
  background: var(--ink);
  transform: skewY(-1.8deg);
  transform-origin: bottom right;
}

.hero-copy h1 {
  font-size: clamp(3rem, 10vw, 12rem);
  font-weight: 900;
  letter-spacing: -0.05em;
  line-height: 0.88;
}

.hero-desc {
  margin: clamp(1.2rem, 3vw, 2rem) 0 0;
  max-width: 36ch;
  font-size: clamp(1rem, 1.6vw, 1.15rem);
  line-height: 1.7;
  color: #1a1a1a;
}

.hero-art {
  position: relative;
  min-height: 32vh;
  max-height: 62vh;
  border-radius: var(--radius);
  overflow: hidden;
  background: #ededed;
}

.hero-art img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.12);
}

.hero-art.is-rot img {
  opacity: 0;
  animation: cutaway 9s infinite;
}

.hero-art.is-rot img.is-first {
  animation-delay: 0s;
}

.hero-art.is-rot img:nth-child(2) {
  animation-delay: 3s;
}

.hero-art.is-rot img:nth-child(3) {
  animation-delay: 6s;
}

@keyframes cutaway {
  0% { opacity: 0; }
  5% { opacity: 1; }
  30% { opacity: 1; }
  36% { opacity: 0; }
  100% { opacity: 0; }
}

/* ---------- 正文 ---------- */

.wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 4.5rem);
  padding: clamp(2.6rem, 7vw, 6rem) var(--gut);
}

.side h2 {
  font-size: 0.9rem;
  letter-spacing: 0.2em;
  font-weight: 900;
  margin-bottom: 0.7rem;
}

.side hr {
  height: 3px;
  margin-bottom: 1rem;
}

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

.toc a {
  display: flex;
  align-items: center;
  min-height: 42px;
  padding: 0.35rem 0;
  font-size: 0.95rem;
  text-decoration: none;
  border-bottom: 1px solid var(--line);
}

.toc a:hover,
.toc a:focus-visible {
  border-bottom-color: var(--ink);
}

.doc {
  max-width: 48rem;
  font-size: 1.0625rem;
}

.doc > section {
  padding-block: clamp(1.9rem, 5vw, 3.4rem);
  border-top: 1px solid var(--ink);
  scroll-margin-top: 7.5rem;
}

.doc > section:first-child {
  border-top: 0;
  padding-top: 0;
}

.doc h2 {
  font-size: clamp(1.7rem, 4.4vw, 2.7rem);
  margin-bottom: 1rem;
}

.doc h3 {
  font-size: clamp(1.25rem, 2.6vw, 1.6rem);
  margin: 2rem 0 0.8rem;
}

.doc h2 + hr {
  margin-bottom: 1.6rem;
}

.doc ul,
.doc ol {
  padding-left: 1.15rem;
  margin: 0 0 1.2rem;
}

.doc li {
  margin-bottom: 0.5rem;
}

.doc img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  margin: 1.4rem 0;
}

.doc blockquote {
  margin: 1.6rem 0;
  padding: 0.4rem 0 0.4rem 1.2rem;
  border-left: 4px solid var(--ink);
  font-size: 1.05rem;
}

.doc table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.4rem 0;
  font-size: 0.98rem;
}

.doc th,
.doc td {
  border-bottom: 1px solid var(--line);
  padding: 0.65rem 0.5rem;
  text-align: left;
}

.doc th {
  border-bottom-color: var(--ink);
}

.doc a {
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

/* ---------- 页脚 ---------- */

.foot {
  border-top: 3px solid var(--ink);
  padding: clamp(2.4rem, 6vw, 4.5rem) var(--gut) 2rem;
  margin-top: clamp(2rem, 6vw, 4rem);
}

.foot-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2rem;
}

.foot address {
  font-style: normal;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.foot-brand {
  font-family: 'Varela Round', 'Nunito Sans', system-ui, sans-serif;
  font-size: 1.25rem;
  line-height: 1.4;
}

.foot-host {
  font-size: 0.95rem;
  color: var(--mute);
  word-break: break-all;
}

.foot-k {
  margin: 0 0 0.6rem;
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  font-weight: 700;
}

.foot ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.foot ul a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0.25rem 0;
  font-size: 0.95rem;
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.foot ul a:hover,
.foot ul a:focus-visible {
  border-bottom-color: var(--ink);
}

.sub {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.sub input {
  flex: 1 1 9rem;
  min-height: 44px;
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  padding: 0.45rem 0.8rem;
  font: inherit;
  font-size: 0.95rem;
  background: var(--paper);
  color: var(--ink);
}

.sub button {
  min-height: 44px;
  padding: 0.45rem 1.2rem;
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  background: var(--ink);
  color: var(--paper);
  font: inherit;
  font-size: 0.95rem;
  cursor: pointer;
}

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

.foot-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  border-top: 1px solid var(--line);
  margin-top: 2.6rem;
  padding-top: 1.3rem;
}

.copy {
  margin: 0;
  font-size: 0.9rem;
  color: var(--mute);
}

.foot-logo {
  font-family: 'Varela Round', 'Nunito Sans', system-ui, sans-serif;
  font-size: 1.1rem;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  min-height: 40px;
}

/* ---------- 断点 ---------- */

@media (min-width: 760px) {
  .foot-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 2.4rem;
  }
}

@media (min-width: 820px) {
  .hero {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: center;
  }

  .hero-art {
    min-height: 46vh;
    max-height: 68vh;
    height: 100%;
  }
}

@media (min-width: 960px) {
  .wrap {
    grid-template-columns: 210px minmax(0, 1fr);
  }

  .side {
    position: sticky;
    top: 7.5rem;
    align-self: start;
  }
}

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

  .site-nav {
    transition: none;
  }

  .hero-art.is-rot img {
    animation: none;
    opacity: 1;
  }

  .hero-art.is-rot img:not(.is-first) {
    display: none;
  }
}

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