@import url('https://fonts.googleapis.com/css2?family=Fredoka:wght@400;500;600;700&family=Nunito:wght@300;400;500;600;700&display=swap');

:root{
  --paper:#fdfbf7;
  --wash:#f5f5f5;
  --ink:#1a1a1a;
  --line:#e2ded6;
  --r:10px;
  --pad:clamp(16px,4vw,44px);
}

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

html{scroll-behavior:smooth}

body{
  margin:0;
  overflow-x:hidden;
  background-color:var(--paper);
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='160' height='160' filter='url(%23n)' opacity='0.05'/%3E%3C/svg%3E");
  color:var(--ink);
  font-family:'Nunito','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  font-size:17px;
  line-height:1.8;
  -webkit-text-size-adjust:100%;
}

h1,h2,h3,h4,.brand,.rail-title{
  font-family:'Fredoka','Nunito','PingFang SC','Microsoft YaHei',sans-serif;
  font-weight:600;
  line-height:1.24;
}

a{color:inherit}
img{max-width:100%}
:focus-visible{outline:2px solid var(--ink);outline-offset:2px}

main [id]{scroll-margin-top:132px}

/* 顶部细条 */
.strip{
  background:var(--ink);
  color:var(--paper);
  padding:7px var(--pad);
  text-align:center;
  font-size:.8125rem;
  line-height:1.4;
}
.strip span{letter-spacing:.26em}

/* 报头 */
.masthead{
  position:sticky;
  top:0;
  z-index:30;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:6px 20px;
  padding:8px var(--pad);
  background:var(--paper);
  border-bottom:1px solid var(--ink);
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:9px;
  min-height:44px;
  padding:0 2px;
  text-decoration:none;
  font-size:1.15rem;
  letter-spacing:.02em;
  border-bottom:2px solid transparent;
}
.brand:hover,.brand:focus-visible{border-bottom-color:var(--ink)}
.brand img{display:block;width:28px;height:28px;border:1px solid var(--line);border-radius:6px;object-fit:cover}

.topnav{flex:1 1 100%;}
.topnav nav{width:100%}
.topnav ul{
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  gap:2px;
  margin:0;
  padding:0;
  list-style:none;
}
.topnav a{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:0 10px;
  font-size:1rem;
  text-decoration:none;
  border:1px solid transparent;
  border-radius:var(--r);
}
.topnav a:hover,.topnav a:focus-visible{background:var(--wash);border-color:var(--ink)}
.topnav a[aria-current="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}

@media (min-width:820px){
  .topnav{flex:0 1 auto}
  .topnav ul{justify-content:flex-end;gap:6px}
}

main{
  max-width:1100px;
  margin:0 auto;
  padding:0 var(--pad);
}

/* 首屏 */
.hero{
  position:relative;
  display:grid;
  place-items:center;
  min-height:62vh;
  padding:clamp(40px,9vw,80px) 0;
}

.collage{
  position:absolute;
  inset:0;
  margin:0;
  pointer-events:none;
}
.collage img{
  position:absolute;
  object-fit:cover;
  background:var(--wash);
  border:1px solid var(--ink);
  border-radius:var(--r);
}
.collage img:nth-of-type(1){
  width:min(40%,300px);
  aspect-ratio:4 / 3;
  top:2%;
  left:0;
  transform:rotate(-2.5deg);
}
.collage img:nth-of-type(2){
  width:min(34%,240px);
  aspect-ratio:3 / 4;
  bottom:2%;
  right:0;
  transform:rotate(2deg);
}

.hero-copy{
  position:relative;
  z-index:2;
  max-width:min(100%,26ch);
  padding:clamp(16px,4vw,32px) clamp(18px,4vw,42px);
  text-align:center;
  background:var(--paper);
  border:1px solid var(--ink);
  border-radius:var(--r);
  box-shadow:7px 7px 0 var(--wash);
}

.hero-copy h1{
  margin:0;
  font-size:clamp(1.85rem,6.4vw,3.3rem);
  letter-spacing:.01em;
  text-wrap:balance;
}

@media (min-width:900px){
  .hero{min-height:68vh}
}

/* 正文 + 右侧栏 */
.spread{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:clamp(22px,4vw,48px);
  padding:8px 0 56px;
  align-items:start;
}
@media (min-width:900px){
  .spread{grid-template-columns:minmax(0,1fr) 248px}
}

.prose{min-width:0}

.prose > div{
  padding:34px 0;
  border-top:1px solid var(--line);
}
.prose > div:first-child{border-top:0;padding-top:6px}

.prose h2{
  margin:.15em 0 .85em;
  font-size:clamp(1.35rem,3.6vw,1.75rem);
  padding-bottom:.35em;
  border-bottom:2px solid var(--ink);
}
.prose h3{
  margin:1.7em 0 .5em;
  font-size:1.16rem;
  letter-spacing:.01em;
}
.prose h3::before{
  content:"";
  display:inline-block;
  width:14px;
  height:2px;
  margin-right:.5em;
  vertical-align:.32em;
  background:var(--ink);
}
.prose p{margin:0 0 1.1em;max-width:64ch}
.prose ul,.prose ol{margin:0 0 1.1em;padding-left:1.35em;max-width:64ch}
.prose li{margin:.4em 0}
.prose li::marker{color:var(--ink)}
.prose a{text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}
.prose a:hover{background:var(--wash)}
.prose strong{font-weight:700}
.prose blockquote{
  margin:1.5em 0;
  padding:14px 18px;
  background:var(--wash);
  border-left:3px solid var(--ink);
  border-radius:0 var(--r) var(--r) 0;
}
.prose blockquote p:last-child{margin-bottom:0}
.prose figure{
  margin:1.5em 0;
  padding:12px;
  background:var(--paper);
  border:1px solid var(--line);
  border-bottom:3px solid var(--ink);
  border-radius:var(--r);
}
.prose figure img{display:block;width:100%;height:auto;border-radius:6px}
.prose figcaption{padding-top:9px;font-size:.9rem;color:#4b4b4b}
.prose img{border-radius:6px}
.prose table{width:100%;border-collapse:collapse;font-size:.98rem;margin:0 0 1.2em}
.prose th,.prose td{border:1px solid var(--line);padding:9px 11px;text-align:left}
.prose th{background:var(--wash)}
.prose hr{border:0;border-top:1px solid var(--line);margin:2em 0}

/* 右侧索引栏 */
.rail{
  padding:16px;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--r);
}
@media (min-width:900px){
  .rail{position:sticky;top:118px}
}

.eyebrow{
  display:block;
  font-size:.8125rem;
  letter-spacing:.22em;
  color:#585858;
}
.rail-title{
  margin:.1em 0 .8em;
  padding-bottom:8px;
  font-size:1.08rem;
  border-bottom:2px solid var(--ink);
}

.rail-nav ul{
  display:grid;
  gap:2px;
  margin:0;
  padding:0;
  list-style:none;
}
.rail-nav a{
  display:flex;
  align-items:center;
  min-height:40px;
  padding:0 8px;
  font-size:.98rem;
  text-decoration:none;
  border-left:2px solid transparent;
}
.rail-nav a:hover,.rail-nav a:focus-visible{background:var(--wash);border-left-color:var(--ink)}
.rail-nav a[aria-current="true"]{font-weight:700;border-left-color:var(--ink);background:var(--wash)}

/* 页脚 */
footer{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:8px 24px;
  margin-top:24px;
  padding:18px var(--pad) 30px;
  border-top:1px solid var(--ink);
  font-size:.95rem;
}
footer p{margin:0;letter-spacing:.02em}
footer small{display:flex;flex-wrap:wrap;gap:6px 20px}
footer small a{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  text-decoration:none;
  border-bottom:1px solid var(--line);
}
footer small a:hover,footer small a:focus-visible{border-bottom-color:var(--ink)}

@media (max-width:560px){
  body{font-size:17px}
  .hero{min-height:58vh;padding:34px 0}
  .hero-copy{max-width:min(100%,22ch);padding:14px 16px;box-shadow:5px 5px 0 var(--wash)}
  .collage img:nth-of-type(1){width:44%;top:0}
  .collage img:nth-of-type(2){width:38%;bottom:0}
  main [id]{scroll-margin-top:150px}
  .prose > div{padding:28px 0}
  .topnav a{padding:0 8px}
}

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

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