@font-face {
  font-family: 'SilkscreenFallback';
  src: local('Courier New');
}

:root {
  --cream: #fff6e9;
  --cream-deep: #f7e6cd;
  --panel: #fffdf7;
  --ink: #46280a;
  --ink-soft: #8a6b47;
  --line: #5d3701;
  --amber: #e8930c;
  --amber-soft: #f6c98a;
  --amber-light: #fbd8a0;
  --mint: #4fa38a;
  --px: 4px;
  --font-pixel: 'Silkscreen', 'SilkscreenFallback', ui-monospace, monospace;
  --font-body: 'Nunito', -apple-system, 'Helvetica Neue', Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background-color: var(--cream);
  background-image: linear-gradient(rgba(93, 55, 1, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(93, 55, 1, 0.045) 1px, transparent 1px);
  background-size: 32px 32px;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

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

.wrap {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 像素风描边：用阶梯阴影替代圆角边框 */
.px-box {
  background: var(--panel);
  border: 3px solid var(--line);
  box-shadow: var(--px) var(--px) 0 rgba(93, 55, 1, 0.18);
}

.pixel-font {
  font-family: var(--font-pixel);
  letter-spacing: 0.04em;
}

/* ---------- header ---------- */
.top {
  position: sticky;
  top: 0;
  z-index: 40;
  border-bottom: 3px solid var(--line);
  background: rgba(255, 246, 233, 0.92);
  backdrop-filter: blur(6px);
}

.top-in {
  display: flex;
  align-items: center;
  gap: 14px;
  height: 68px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  margin-right: auto;
}

.brand img {
  width: 38px;
  height: 38px;
  border: 2px solid var(--line);
}

.brand span {
  font-family: var(--font-pixel);
  font-size: 20px;
}

.top nav {
  display: flex;
  gap: 22px;
}

.top nav a {
  font-size: 14px;
  font-family: var(--font-pixel);
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 3px solid transparent;
}

.top nav a:hover {
  border-bottom-color: var(--amber);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 18px;
  font-family: var(--font-pixel);
  font-size: 14px;
  text-decoration: none;
  color: var(--ink);
  background: var(--amber-light);
  border: 3px solid var(--line);
  box-shadow: var(--px) var(--px) 0 var(--line);
  transition: transform 0.08s linear, box-shadow 0.08s linear;
}

.btn:hover {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 var(--line);
}

.btn:active {
  transform: translate(var(--px), var(--px));
  box-shadow: 0 0 0 var(--line);
}

.btn-primary {
  background: var(--amber);
  color: #fffaf0;
}

.btn-ghost {
  background: transparent;
  box-shadow: none;
}

/* ---------- hero ---------- */
.hero {
  padding: 76px 0 40px;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 56px;
  align-items: center;
}

.tagline {
  display: inline-block;
  font-family: var(--font-pixel);
  font-size: 12px;
  padding: 6px 10px;
  background: var(--cream-deep);
  border: 2px solid var(--line);
  margin-bottom: 22px;
}

.hero h1 {
  font-family: var(--font-pixel);
  font-size: clamp(34px, 5vw, 54px);
  line-height: 1.18;
  margin: 0 0 18px;
}

.hero h1 em {
  font-style: normal;
  color: var(--amber);
}

.hero p.lead {
  font-size: 19px;
  color: var(--ink-soft);
  margin: 0 0 28px;
  max-width: 30em;
}

.cta-row {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.hint {
  font-size: 13px;
  color: var(--ink-soft);
  margin-top: 16px;
}

/* ---------- 可交互像素画板 ---------- */
.studio {
  padding: 16px;
}

.studio-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-pixel);
  font-size: 12px;
  padding-bottom: 12px;
  border-bottom: 3px solid var(--line);
  margin-bottom: 14px;
}

.studio-bar .dots {
  display: flex;
  gap: 5px;
}

.studio-bar .dots i {
  width: 9px;
  height: 9px;
  background: var(--amber);
  border: 2px solid var(--line);
}

#canvas {
  display: grid;
  grid-template-columns: repeat(16, 1fr);
  aspect-ratio: 1;
  border: 3px solid var(--line);
  background: #fffdf7;
  touch-action: none;
  cursor: crosshair;
}

#canvas i {
  border-right: 1px solid rgba(93, 55, 1, 0.07);
  border-bottom: 1px solid rgba(93, 55, 1, 0.07);
}

.tools {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 14px;
  flex-wrap: wrap;
}

.swatches {
  display: flex;
  gap: 6px;
  margin-right: auto;
}

.swatches button {
  width: 26px;
  height: 26px;
  padding: 0;
  border: 3px solid var(--line);
  cursor: pointer;
}

.swatches button[aria-pressed='true'] {
  outline: 3px solid var(--amber);
  outline-offset: 3px;
}

.mini {
  font-family: var(--font-pixel);
  font-size: 11px;
  padding: 8px 10px;
  background: var(--cream-deep);
  border: 3px solid var(--line);
  cursor: pointer;
  color: var(--ink);
}

.mini:hover {
  background: var(--amber-light);
}

/* ---------- 区块标题 ---------- */
section {
  padding: 74px 0;
}

.sec-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 34px;
}

.sec-head b {
  font-family: var(--font-pixel);
  font-size: 13px;
  color: var(--amber);
}

.sec-head h2 {
  font-family: var(--font-pixel);
  font-size: clamp(24px, 3.4vw, 34px);
  margin: 0;
}

.rule {
  flex: 1;
  height: 3px;
  background: repeating-linear-gradient(90deg, var(--line) 0 6px, transparent 6px 12px);
}

/* ---------- 展柜：一次仅展示一张截图 ---------- */
.showcase {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 48px;
  align-items: start;
}

.chapters {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 3px solid var(--line);
}

.chapters li {
  border-bottom: 3px solid var(--line);
}

.chapters button {
  width: 100%;
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 4px 18px;
  align-items: start;
  text-align: left;
  padding: 20px 6px;
  background: transparent;
  border: 0;
  cursor: pointer;
  color: var(--ink-soft);
  font-family: inherit;
  font-size: 15px;
}

.chapters .idx {
  font-family: var(--font-pixel);
  font-size: 13px;
  color: var(--amber);
  padding-top: 4px;
}

.chapters .name {
  font-family: var(--font-pixel);
  font-size: 17px;
  color: var(--ink);
}

.chapters .desc {
  grid-column: 2;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height 0.28s ease, opacity 0.2s ease;
}

.chapters button[aria-selected='true'] {
  background: rgba(232, 147, 12, 0.09);
}

.chapters button[aria-selected='true'] .desc {
  max-height: 190px;
  opacity: 1;
  margin-top: 6px;
}

.frame {
  position: sticky;
  top: 96px;
  padding: 14px 14px 18px;
  background: linear-gradient(180deg, #f9dda9, #f0c079);
}

.frame .glass {
  position: relative;
  border: 3px solid var(--line);
  background: #fdf3e1;
  overflow: hidden;
  aspect-ratio: 621 / 1344;
}

.frame .glass img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity 0.22s steps(4, end);
}

.frame .glass img.on {
  opacity: 1;
}

.plate {
  margin-top: 12px;
  text-align: center;
  font-family: var(--font-pixel);
  font-size: 11px;
  color: var(--line);
}

/* ---------- 纯文字卡片区 ---------- */
.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.card {
  padding: 26px 22px;
}

.card .glyph {
  font-family: var(--font-pixel);
  font-size: 12px;
  color: var(--amber);
  margin-bottom: 12px;
  display: block;
}

.card h3 {
  font-family: var(--font-pixel);
  font-size: 16px;
  margin: 0 0 10px;
}

.card p {
  margin: 0;
  font-size: 15px;
  color: var(--ink-soft);
}

.card:nth-child(2) {
  margin-top: 26px;
}

.card:nth-child(3) {
  margin-top: 52px;
}

/* ---------- 安全承诺 ---------- */
.pledge {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 44px;
  align-items: center;
  padding: 40px;
  background: var(--cream-deep);
}

.pledge h2 {
  font-family: var(--font-pixel);
  font-size: clamp(22px, 3vw, 30px);
  margin: 0 0 14px;
}

.pledge p {
  margin: 0 0 8px;
  color: var(--ink-soft);
}

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

.facts li {
  display: flex;
  gap: 14px;
  padding: 14px 0;
  border-bottom: 3px dotted rgba(93, 55, 1, 0.35);
  font-size: 15px;
}

.facts li:last-child {
  border-bottom: 0;
}

.facts b {
  font-family: var(--font-pixel);
  font-size: 13px;
  color: var(--amber);
  min-width: 74px;
}

/* ---------- 下载 ---------- */
.download {
  text-align: center;
}

.download img.mark {
  width: 96px;
  height: 96px;
  margin: 0 auto 22px;
  border: 3px solid var(--line);
  box-shadow: var(--px) var(--px) 0 var(--line);
}

.download h2 {
  font-family: var(--font-pixel);
  font-size: clamp(24px, 3.6vw, 36px);
  margin: 0 0 14px;
}

.download p {
  color: var(--ink-soft);
  max-width: 34em;
  margin: 0 auto 26px;
}

/* ---------- footer ---------- */
footer {
  border-top: 3px solid var(--line);
  padding: 34px 0 46px;
  font-size: 14px;
  color: var(--ink-soft);
}

.foot-in {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  align-items: center;
}

.foot-in nav {
  display: flex;
  gap: 18px;
  margin-left: auto;
  flex-wrap: wrap;
}

footer a {
  text-decoration: none;
  border-bottom: 2px solid var(--amber-light);
}

footer a:hover {
  border-bottom-color: var(--amber);
}

/* ---------- 协议文档页 ---------- */
.doc {
  max-width: 820px;
  padding: 56px 0 80px;
}

.doc h1 {
  font-family: var(--font-pixel);
  font-size: clamp(26px, 4vw, 38px);
  margin: 0 0 8px;
}

.doc .eff {
  font-family: var(--font-pixel);
  font-size: 12px;
  color: var(--amber);
  margin-bottom: 34px;
}

.doc h2 {
  font-family: var(--font-pixel);
  font-size: 17px;
  margin: 44px 0 12px;
  padding-left: 14px;
  border-left: 6px solid var(--amber);
}

.doc p,
.doc li {
  color: #5b4023;
}

.doc ul {
  padding-left: 22px;
}

.doc li {
  margin-bottom: 10px;
}

.doc hr {
  border: 0;
  height: 3px;
  background: repeating-linear-gradient(90deg, rgba(93, 55, 1, 0.4) 0 6px, transparent 6px 12px);
  margin: 40px 0;
}

.doc .toc {
  padding: 20px 24px;
  margin-bottom: 10px;
}

.doc .toc a {
  text-decoration: none;
  border-bottom: 2px solid var(--amber-light);
}

@media (max-width: 900px) {
  .hero,
  .showcase,
  .pledge {
    grid-template-columns: 1fr;
    gap: 34px;
  }
  .cards {
    grid-template-columns: 1fr;
  }
  .card:nth-child(2),
  .card:nth-child(3) {
    margin-top: 0;
  }
  .frame {
    position: static;
    max-width: 340px;
    margin: 0 auto;
  }
  .top nav {
    display: none;
  }
  section {
    padding: 52px 0;
  }
  .pledge {
    padding: 26px;
  }
}