/* 黑白瑞士网格 */
:root {
  --ink: #000;
  --paper: #fff;
  --grey: #d8d8d8;
  --line: #000;
  --pad: 1.25rem;
  --dock: 5.5rem;
}

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

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

body {
  margin: 0;
  padding-bottom: calc(var(--dock) + 2rem);
  background: var(--paper);
  color: var(--ink);
  font-family: "Atkinson Hyperlegible", system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.65;
  overflow-x: clip;
}

body > * {
  max-width: 100%;
}

a {
  color: var(--ink);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.22em;
}

a:hover {
  text-decoration-thickness: 2px;
}

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

h1,
h2,
h3 {
  line-height: 1.15;
  letter-spacing: -0.015em;
  margin: 0 0 0.6em;
}

h2 {
  font-size: clamp(1.55rem, 4vw, 2.3rem);
}

h3 {
  font-size: clamp(1.2rem, 2.6vw, 1.5rem);
}

small {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  font-weight: 700;
  margin-bottom: 0.35rem;
}

p {
  margin: 0 0 1.1em;
}

ul,
ol {
  margin: 0 0 1.2em;
  padding-left: 1.3em;
}

/* 主网格 */
main {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--pad);
  display: grid;
  grid-template-columns: 236px minmax(0, 1fr);
  column-gap: 3.5rem;
}

/* 满屏首屏 */
.hero {
  grid-column: 1 / -1;
  position: relative;
  width: 100vw;
  margin-inline: calc(50% - 50vw);
  min-height: 100svh;
  display: grid;
  place-items: center;
  overflow: hidden;
  padding: 3rem var(--pad);
  border-bottom: 2px solid var(--ink);
}

.hero-art {
  position: absolute;
  inset: 0;
  margin: 0;
  z-index: 0;
}

.tile {
  position: absolute;
  z-index: 1;
  overflow: hidden;
  background: var(--grey);
}

.tile img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.08);
}

.t1 {
  left: 0;
  top: 9%;
  width: 38%;
  height: 45%;
}

.t2 {
  right: 4%;
  bottom: 8%;
  width: 29%;
  height: 36%;
  background: var(--ink);
}

.ph {
  display: block;
  width: 100%;
  height: 100%;
}

.ph1 {
  background: var(--ink);
}

.ph2 {
  background: var(--grey);
}

.band {
  position: absolute;
  z-index: 2;
  left: -28%;
  top: 62%;
  width: 156%;
  height: 9vh;
  min-height: 52px;
  background: var(--ink);
  transform: rotate(-5deg);
}

.hero-copy {
  position: relative;
  z-index: 3;
  background: var(--paper);
  max-width: min(780px, 88vw);
  padding: 2.2rem 1.6rem;
  text-align: center;
}

.hero-copy h1 {
  font-size: clamp(2.1rem, 7.5vw, 5rem);
  letter-spacing: -0.03em;
  margin-bottom: 0.45em;
  overflow-wrap: anywhere;
}

.lead {
  font-size: clamp(1rem, 2.4vw, 1.2rem);
  max-width: 46ch;
  margin: 0 auto 1.4rem;
}

.jump {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 1.8rem;
  background: var(--ink);
  color: var(--paper);
  text-decoration: none;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.jump:hover {
  background: var(--paper);
  color: var(--ink);
  outline: 2px solid var(--ink);
}

/* 左侧栏 */
.side {
  grid-column: 1;
  grid-row: 2 / span 40;
  align-self: start;
  position: sticky;
  top: 1.5rem;
  margin-top: 2.5rem;
  padding: 0 1.6rem 2rem 0;
  border-right: 2px solid var(--ink);
}

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

.side li {
  border-bottom: 1px solid var(--ink);
}

.side a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 0.15rem 0;
  text-decoration: none;
  font-weight: 700;
  line-height: 1.2;
}

.side a:hover {
  padding-left: 0.5rem;
  background: var(--ink);
  color: var(--paper);
}

/* 正文区块 */
main > article:not(.hero) {
  grid-column: 2;
  padding: 3.5rem 0;
  border-top: 2px solid var(--ink);
  scroll-margin-top: 1rem;
}

main > article:not(.hero) h2 {
  margin-bottom: 0.8em;
}

main > article:not(.hero) p,
main > article:not(.hero) li {
  max-width: 68ch;
}

main > article:not(.hero) ul,
main > article:not(.hero) ol {
  max-width: 66ch;
}

main > article:not(.hero) img {
  width: 100%;
  filter: grayscale(1);
}

main > article:not(.hero) figure {
  margin: 1.5rem 0;
}

main > article:not(.hero) blockquote {
  margin: 1.5rem 0;
  padding: 0.4rem 0 0.4rem 1.2rem;
  border-left: 8px solid var(--ink);
  font-size: 1.08rem;
}

main > article:not(.hero) table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.2rem 0;
  font-size: 1rem;
}

main > article:not(.hero) th,
main > article:not(.hero) td {
  border: 1px solid var(--ink);
  padding: 0.6rem 0.7rem;
  text-align: left;
  vertical-align: top;
}

main > article:not(.hero) th {
  background: var(--ink);
  color: var(--paper);
}

main > article:not(.hero) hr {
  border: 0;
  border-top: 2px solid var(--ink);
  margin: 2.2rem 0;
}

/* 入场 */
.js main > article:not(.hero) {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.js main > article:not(.hero).in {
  opacity: 1;
  transform: none;
}

.js main > article:not(.hero):nth-of-type(2n) {
  transition-delay: 0.07s;
}

.js main > article:not(.hero):nth-of-type(3n) {
  transition-delay: 0.13s;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .js main > article:not(.hero) {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .band {
    transform: none;
  }
}

/* 底部固定条 */
.dock {
  position: fixed;
  z-index: 60;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.7rem var(--pad) calc(0.7rem + env(safe-area-inset-bottom, 0px));
  background: var(--paper);
  border-top: 2px solid var(--ink);
}

.brand {
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  margin-right: auto;
  padding: 0.5rem 0;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  overflow-wrap: anywhere;
}

.menu-btn,
.dock-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 1rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
}

.menu-btn {
  border: 2px solid var(--ink);
  background: var(--paper);
  color: var(--ink);
}

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

.dock-cta {
  background: var(--ink);
  color: var(--paper);
}

.dock-cta:hover {
  background: var(--paper);
  color: var(--ink);
  outline: 2px solid var(--ink);
}

/* 全屏遮罩菜单 */
.nav-check {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
}

.overlay {
  position: fixed;
  z-index: 100;
  inset: 0;
  background: var(--ink);
  color: var(--paper);
  padding: 1.4rem var(--pad) 3rem;
  overflow-y: auto;
  visibility: hidden;
  transform: translateY(-102%);
  transition: transform 0.3s ease, visibility 0.3s;
}

.nav-check:checked ~ .overlay {
  visibility: visible;
  transform: translateY(0);
}

.nav-check:focus-visible ~ .dock .menu-btn {
  outline: 3px solid var(--ink);
  outline-offset: 2px;
}

.overlay-close {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 1.1rem;
  border: 2px solid var(--paper);
  font-weight: 700;
  letter-spacing: 0.08em;
  cursor: pointer;
}

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

.overlay-nav ul {
  list-style: none;
  margin: 2.5rem 0 0;
  padding: 0;
  border-top: 1px solid var(--paper);
}

.overlay-nav li {
  border-bottom: 1px solid var(--paper);
}

.overlay-nav a {
  display: flex;
  align-items: center;
  min-height: 56px;
  padding: 0.35rem 0;
  color: var(--paper);
  text-decoration: none;
  font-size: clamp(1.35rem, 5.2vw, 2.2rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  transition: padding-left 0.22s ease;
}

.overlay-nav a:hover {
  padding-left: 0.6rem;
  text-decoration: underline;
}

/* 页脚 */
.foot {
  max-width: 1200px;
  margin: 4rem auto 0;
  padding: 1.6rem var(--pad) 0;
  border-top: 2px solid var(--ink);
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 1rem 2rem;
}

.foot-title {
  min-width: 90px;
}

.foot-title h2 {
  font-size: 1rem;
  margin: 0;
  letter-spacing: 0.1em;
}

.foot-nav {
  flex: 1 1 320px;
}

.foot-nav dl {
  display: flex;
  flex-wrap: wrap;
  gap: 0.15rem 1.4rem;
  margin: 0;
}

.foot-nav dt,
.foot-nav dd {
  margin: 0;
}

.foot-nav dt a,
.foot-nav dd a,
.foot-list a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0.15rem 0;
}

.foot-nav dt a {
  font-weight: 700;
  text-decoration: none;
}

.foot-nav dd a {
  text-decoration: none;
}

.foot address {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 0.8rem;
  font-style: normal;
}

.foot address span:first-child {
  font-weight: 700;
}

.foot-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0 1.2rem;
  margin: 0;
  padding: 0;
}

.foot-list a {
  text-decoration: underline;
}

/* 窄屏 */
@media (max-width: 860px) {
  body {
    font-size: 16px;
  }

  main {
    grid-template-columns: minmax(0, 1fr);
    column-gap: 0;
  }

  .hero {
    grid-column: 1;
    padding: 2.2rem var(--pad);
    min-height: 100svh;
  }

  .t1 {
    width: 52%;
    height: 31%;
    top: 6%;
  }

  .t2 {
    width: 42%;
    height: 26%;
    right: 0;
    bottom: 5%;
  }

  .band {
    top: 66%;
    height: 7vh;
  }

  .hero-copy {
    max-width: 94vw;
    padding: 1.6rem 1.1rem;
  }

  .side {
    grid-column: 1;
    grid-row: auto;
    position: static;
    margin: 0;
    padding: 2rem 0 1.5rem;
    border-right: 0;
    border-bottom: 2px solid var(--ink);
  }

  .side ol {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0;
    border-top: 0;
  }

  .side li {
    border-top: 1px solid var(--ink);
  }

  .side li:nth-child(odd) {
    border-right: 1px solid var(--ink);
    padding-right: 0.7rem;
  }

  .side li:nth-child(even) {
    padding-left: 0.7rem;
  }

  main > article:not(.hero) {
    grid-column: 1;
    padding: 2.6rem 0;
  }

  .foot {
    margin-top: 2.6rem;
    padding-bottom: 0.5rem;
  }

  .foot-nav {
    flex-basis: 100%;
  }

  .foot-nav dl {
    gap: 0 1rem;
  }

  .dock {
    gap: 0.55rem;
  }

  .brand {
    font-size: 0.95rem;
  }

  .menu-btn,
  .dock-cta {
    padding: 0 0.8rem;
    letter-spacing: 0.02em;
  }
}

@media (max-width: 380px) {
  .brand {
    font-size: 0.88rem;
  }

  .menu-btn,
  .dock-cta {
    padding: 0 0.6rem;
    font-size: 0.92rem;
  }
}

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