@import url('https://fonts.googleapis.com/css2?family=Amatic+SC:wght@400;700&family=Cabin:wght@400;500;600;700&display=swap');

:root {
  --ink: #000000;
  --blue: #3bb1ff;
  --red: #ff5252;
  --paper: #fffdf4;
  --sh: 5px 5px 0 #000000;
  --line: 3px solid #000000;
}

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

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

body {
  margin: 0;
  overflow-x: clip;
  background: var(--paper);
  color: var(--ink);
  font-family: 'Cabin', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  font-size: 17px;
  line-height: 1.65;
  font-weight: 500;
}

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

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

:focus-visible {
  outline: 4px solid var(--red);
  outline-offset: 2px;
}

h1,
h2,
h3,
h4 {
  font-family: 'Amatic SC', 'Cabin', system-ui, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  font-weight: 700;
  line-height: 1.18;
  letter-spacing: 0.01em;
  margin: 0 0 0.5em;
}

p {
  margin: 0 0 1em;
}

/* ---------- 顶栏 ---------- */
.masthead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 12px 18px;
  background: var(--blue);
  border-bottom: var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  text-decoration: none;
  color: var(--ink);
}

.brand-txt {
  font-family: 'Amatic SC', 'Cabin', system-ui, 'PingFang SC', sans-serif;
  font-weight: 700;
  font-size: 30px;
  line-height: 1;
  letter-spacing: 0.06em;
}

.mark {
  display: inline-grid;
  place-items: center;
  width: 44px;
  height: 44px;
  flex: 0 0 auto;
  border: var(--line);
  background: #ffffff;
  box-shadow: 4px 4px 0 #000000;
  font-family: 'Amatic SC', sans-serif;
  font-weight: 700;
  font-size: 26px;
  overflow: hidden;
}

img.mark {
  object-fit: cover;
}

/* ---------- 汉堡遮罩菜单 ---------- */
.drawer {
  position: relative;
}

.drawer > summary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 8px 16px;
  border: var(--line);
  background: #ffffff;
  box-shadow: 4px 4px 0 #000000;
  font-weight: 700;
  letter-spacing: 0.12em;
  cursor: pointer;
  list-style: none;
  user-select: none;
}

.drawer > summary::-webkit-details-marker {
  display: none;
}

.bars {
  display: block;
  width: 22px;
  height: 3px;
  background: var(--ink);
  box-shadow: 0 7px 0 var(--ink), 0 -7px 0 var(--ink);
}

.drawer[open] > summary {
  position: relative;
  z-index: 80;
  background: var(--red);
}

.drawer[open] > summary .bars {
  background: #ffffff;
  box-shadow: 0 7px 0 #ffffff, 0 -7px 0 #ffffff;
}

.drawer-menu {
  position: fixed;
  inset: 0;
  z-index: 70;
  margin: 0;
  padding: 92px 20px 34px;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  overflow-y: auto;
  background: var(--red);
}

.drawer[open] .drawer-menu {
  animation: pop 0.18s ease-out both;
}

@keyframes pop {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.drawer-menu a {
  display: flex;
  align-items: center;
  min-height: 54px;
  padding: 10px 18px;
  border: var(--line);
  background: #ffffff;
  box-shadow: var(--sh);
  text-decoration: none;
  font-weight: 700;
  font-size: 19px;
}

.drawer-menu a:hover {
  background: var(--blue);
}

/* ---------- 粘性锚点条 ---------- */
.strip {
  position: sticky;
  top: 0;
  z-index: 40;
  background: #ffffff;
  border-bottom: var(--line);
  padding: 0 10px;
  overflow-x: auto;
  overscroll-behavior-x: contain;
}

.strip ul {
  display: flex;
  width: max-content;
  min-height: 52px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.strip a {
  display: flex;
  align-items: center;
  min-height: 52px;
  padding: 0 14px;
  text-decoration: none;
  font-weight: 700;
  font-size: 16px;
  white-space: nowrap;
}

.strip li + li a {
  border-left: var(--line);
}

.strip a:hover {
  background: var(--blue);
}

/* ---------- 首屏 ---------- */
.hero {
  padding: clamp(22px, 4vw, 52px) 18px;
  border-bottom: var(--line);
  background-color: var(--paper);
  background-image: radial-gradient(rgba(0, 0, 0, 0.22) 1.7px, transparent 1.8px);
  background-size: 16px 16px;
}

.hero-grid {
  max-width: 1120px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  gap: clamp(20px, 4vw, 46px);
  align-items: center;
  min-height: 70vh;
}

.hero-art {
  margin: 0;
  aspect-ratio: 4 / 3;
  border: var(--line);
  background: var(--blue);
  box-shadow: 10px 10px 0 var(--red);
  overflow: hidden;
  will-change: transform;
}

.hero-art .hero-img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  border: 0;
  box-shadow: none;
}

.hero-slab {
  display: block;
  width: 100%;
  height: 100%;
  background: repeating-linear-gradient(45deg, var(--blue) 0 14px, #ffffff 14px 28px);
}

.hero-copy {
  text-align: right;
}

.hero-copy h1 {
  font-size: clamp(36px, 7.2vw, 66px);
  margin: 0 0 14px;
  text-shadow: 5px 5px 0 var(--blue);
}

.hero-copy .lead {
  margin: 0 0 0 auto;
  max-width: 44ch;
  font-size: clamp(17px, 2.1vw, 20px);
  font-weight: 600;
  color: #111111;
}

/* ---------- 正文骨架 ---------- */
.wrap {
  max-width: 1120px;
  margin: 0 auto;
  padding: clamp(26px, 4vw, 54px) 18px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 272px;
  gap: clamp(18px, 3vw, 34px);
  align-items: start;
}

.body {
  min-width: 0;
}

.prose {
  min-width: 0;
}

.prose section {
  background: #ffffff;
  border: var(--line);
  border-bottom: 9px solid var(--blue);
  box-shadow: var(--sh);
  padding: 22px 20px;
  scroll-margin-top: 84px;
}

.prose section:nth-of-type(even) {
  border-bottom-color: var(--red);
}

.prose section + section {
  margin-top: 30px;
}

.prose h2 {
  font-size: clamp(26px, 3.6vw, 40px);
  margin: 0.1em 0 0.45em;
}

.prose h3 {
  font-size: clamp(20px, 2.4vw, 25px);
  margin: 1.2em 0 0.4em;
}

.prose h4 {
  font-size: 19px;
  margin: 1.1em 0 0.35em;
}

.prose small {
  display: inline-block;
  background: var(--ink);
  color: #ffffff;
  font-family: 'Cabin', system-ui, sans-serif;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.14em;
  line-height: 1.5;
  padding: 3px 10px;
  margin-bottom: 10px;
}

.prose p,
.prose li {
  font-size: 17px;
}

.prose ul,
.prose ol {
  margin: 0 0 1em;
  padding-left: 1.25em;
}

.prose li {
  margin: 0.35em 0;
}

.prose a {
  text-decoration: none;
  font-weight: 600;
  border-bottom: 3px solid var(--red);
}

.prose a:hover {
  background: var(--blue);
}

.prose blockquote {
  margin: 1.2em 0;
  padding: 14px 18px;
  background: #eef8ff;
  border: var(--line);
  border-left: 9px solid var(--red);
  box-shadow: var(--sh);
}

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

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 1em 0;
}

.prose th,
.prose td {
  border: 2px solid var(--ink);
  padding: 8px 10px;
  text-align: left;
  font-size: 16px;
}

.prose th {
  background: var(--blue);
}

.prose code {
  background: var(--ink);
  color: #ffffff;
  padding: 1px 6px;
  font-size: 15px;
}

.prose img {
  border: var(--line);
  box-shadow: var(--sh);
}

.prose hr {
  border: 0;
  border-top: var(--line);
  margin: 1.6em 0;
}

/* ---------- 右侧速览 ---------- */
.side {
  position: sticky;
  top: 78px;
  border: var(--line);
  background: #ffffff;
  box-shadow: 7px 7px 0 var(--blue);
  padding: 16px;
}

.side small {
  display: inline-block;
  background: var(--ink);
  color: #ffffff;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.16em;
  line-height: 1.5;
  padding: 3px 10px;
}

.side h2 {
  font-size: 28px;
  margin: 10px 0 12px;
}

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

.toc li + li {
  margin-top: 9px;
}

.toc a {
  display: flex;
  align-items: center;
  gap: 9px;
  min-height: 44px;
  padding: 6px 9px;
  border: 3px solid #000000;
  background: #ffffff;
  box-shadow: 3px 3px 0 #000000;
  text-decoration: none;
  font-weight: 600;
  font-size: 16px;
  line-height: 1.4;
}

.toc a:hover {
  background: var(--blue);
}

.num {
  flex: 0 0 auto;
  font-family: 'Amatic SC', sans-serif;
  font-weight: 700;
  font-size: 18px;
  line-height: 1.4;
  background: var(--ink);
  color: #ffffff;
  padding: 0 6px;
}

/* ---------- 页脚 ---------- */
.foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 18px 28px;
  padding: 26px 18px;
  border-top: var(--line);
  background: var(--blue);
}

.f-brand {
  flex: 0 0 auto;
}

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

.f-nav ul {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.f-nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 6px;
  text-decoration: none;
  font-weight: 600;
  font-size: 16px;
  border-bottom: 3px solid transparent;
}

.f-nav a:hover {
  border-bottom-color: #000000;
}

.f-side {
  flex: 0 0 auto;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 10px;
}

.sub {
  display: flex;
}

.sub input {
  min-height: 46px;
  width: 160px;
  padding: 0 12px;
  border: var(--line);
  border-right: 0;
  background: #ffffff;
  font: inherit;
  font-size: 16px;
  color: var(--ink);
}

.sub button {
  min-height: 46px;
  padding: 0 16px;
  border: var(--line);
  background: var(--red);
  box-shadow: 4px 4px 0 #000000;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.sub button:hover {
  background: #ffffff;
}

.copy {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
}

/* ---------- 动效 ---------- */
html.anim .rv {
  opacity: 0;
  transform: translateY(18px);
}

html.anim .rv.in {
  opacity: 1;
  transform: none;
  transition: opacity 0.5s ease-out, transform 0.5s ease-out;
}

/* ---------- 断点 ---------- */
@media (max-width: 940px) {
  .wrap {
    grid-template-columns: minmax(0, 1fr);
  }

  .side {
    position: static;
    order: 2;
  }

  .body {
    order: 1;
  }
}

@media (max-width: 860px) {
  .hero-grid {
    grid-template-columns: minmax(0, 1fr);
    min-height: 0;
  }

  .hero-copy {
    order: -1;
    text-align: left;
  }

  .hero-copy .lead {
    margin-left: 0;
  }

  .hero-art {
    aspect-ratio: 16 / 10;
    box-shadow: 7px 7px 0 var(--red);
  }

  .foot {
    flex-direction: column;
    align-items: flex-start;
  }

  .f-nav ul {
    justify-content: flex-start;
  }

  .f-side {
    align-items: flex-start;
  }
}

@media (max-width: 560px) {
  body {
    font-size: 16px;
  }

  .masthead {
    padding: 10px 12px;
  }

  .brand-txt {
    font-size: 26px;
  }

  .mark {
    width: 40px;
    height: 40px;
  }

  .hero {
    padding: 20px 12px 24px;
  }

  .wrap {
    padding: 24px 12px 34px;
  }

  .prose section {
    padding: 18px 14px;
    border-bottom-width: 7px;
  }

  .prose p,
  .prose li {
    font-size: 16px;
  }

  .side {
    box-shadow: 5px 5px 0 var(--blue);
  }

  .sub input {
    width: 100%;
    min-width: 0;
  }

  .f-nav ul {
    gap: 2px 10px;
  }
}

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

  html.anim .rv {
    opacity: 1;
    transform: none;
  }

  .drawer[open] .drawer-menu {
    animation: none;
  }

  .hero-art {
    transform: none !important;
  }
}

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