/* ==========================================================================
   四季中心 · 共享站点样式 /assets/site.css
   奶油纸底 + 深棕黑细线 + 四季四色编码 + 直角索引墙
   ========================================================================== */

/* 1. 变量
   ========================================================================== */
:root{
  --cream:#F7F1E6;
  --ink:#241F1B;
  --blue:#2E6F8E;
  --spring:#79B79A;
  --clay:#D86B2E;
  --mist:#C8C5BD;
  --paper:#FFFDF7;
  --deep:#163E4A;
  --light-cyan:#DDEBE6;
  --light-clay:#F5D9C9;
  --ok:#3E7A5C;
  --warn:#B23A2A;

  --rule:rgba(36,31,27,.16);
  --rule-strong:rgba(36,31,27,.42);
  --on-deep:rgba(247,241,230,.74);
  --on-deep-soft:rgba(247,241,230,.52);

  --font-body:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-mono:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --wrap:1280px;
  --gutter:48px;
  --step:24px;
  --print-shadow:3px 3px 0 var(--ink);
}

@media (max-width:1024px){
  :root{ --gutter:32px; --step:20px; }
}
@media (max-width:640px){
  :root{ --gutter:20px; --step:16px; }
}

/* 2. Reset
   ========================================================================== */
*,
*::before,
*::after{ box-sizing:border-box; }

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

body,
h1,h2,h3,h4,h5,h6,
p,figure,blockquote,dl,dd,ul,ol{
  margin:0;
}

ul,ol{
  padding:0;
  list-style:none;
}

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

a{ color:inherit; }

button{
  font:inherit;
  color:inherit;
  background:none;
  border:0;
}

h1,h2,h3,h4{
  font-weight:700;
  line-height:1.25;
  letter-spacing:-.01em;
}

/* 3. 基础排版
   ========================================================================== */
body{
  background:var(--cream);
  color:var(--ink);
  font-family:var(--font-body);
  font-size:16px;
  font-weight:400;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

::selection{
  background:var(--clay);
  color:var(--paper);
}

:focus-visible{
  outline:2px solid var(--clay);
  outline-offset:3px;
}

.has-js [data-reveal]{
  opacity:0;
  transform:translateY(14px);
  transition:opacity .5s ease, transform .5s ease;
}

.has-js [data-reveal].is-revealed{
  opacity:1;
  transform:none;
}

/* 4. 容器与节奏
   ========================================================================== */
.wrap{
  width:100%;
  max-width:var(--wrap);
  margin-inline:auto;
  padding-inline:var(--gutter);
}

.section{
  padding-block:clamp(40px,6vw,72px);
}

.section--tight{
  padding-block:clamp(24px,3vw,40px);
}

.grid{
  display:grid;
  gap:var(--step);
}

.grid--2{ grid-template-columns:repeat(2,minmax(0,1fr)); }
.grid--3{ grid-template-columns:repeat(3,minmax(0,1fr)); }
.grid--4{ grid-template-columns:repeat(4,minmax(0,1fr)); }

@media (max-width:1000px){
  .grid--3,
  .grid--4{ grid-template-columns:repeat(2,minmax(0,1fr)); }
}
@media (max-width:620px){
  .grid--2,
  .grid--3,
  .grid--4{ grid-template-columns:minmax(0,1fr); }
}

/* 5. 四季刻度条
   ========================================================================== */
.season-bar{
  display:grid;
  grid-template-columns:repeat(4,1fr);
  height:6px;
  width:100%;
}

.season-bar span:nth-child(1){ background:var(--spring); }
.season-bar span:nth-child(2){ background:var(--blue); }
.season-bar span:nth-child(3){ background:var(--clay); }
.season-bar span:nth-child(4){ background:var(--mist); }

/* 6. 跳转链接
   ========================================================================== */
.skip-link{
  position:absolute;
  left:12px;
  top:-80px;
  z-index:200;
  display:inline-block;
  padding:12px 20px;
  background:var(--deep);
  color:var(--cream);
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.08em;
  text-decoration:none;
  border:1px solid var(--cream);
  transition:top .18s ease;
}

.skip-link:focus{
  top:12px;
}

/* 7. 头部
   ========================================================================== */
.site-header{
  position:relative;
  z-index:60;
  background:var(--cream);
}

.site-header__top{
  background:var(--cream);
  border-bottom:1px solid var(--rule);
}

.site-header__top-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:32px;
  min-height:78px;
  padding-block:14px;
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:14px;
  text-decoration:none;
  color:var(--ink);
}

.brand__mark{
  display:grid;
  grid-template-columns:repeat(2,9px);
  grid-template-rows:repeat(2,9px);
  gap:3px;
  flex:none;
}

.brand__mark i{
  display:block;
  background:var(--ink);
}

.brand__mark i:nth-child(1){ background:var(--spring); }
.brand__mark i:nth-child(2){ background:var(--blue); }
.brand__mark i:nth-child(3){ background:var(--clay); }
.brand__mark i:nth-child(4){ background:var(--mist); }

.brand__text{
  display:flex;
  flex-direction:column;
  gap:3px;
  line-height:1.15;
}

.brand__name{
  font-size:26px;
  font-weight:900;
  letter-spacing:.05em;
}

.brand__descriptor{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  color:rgba(36,31,27,.6);
}

.brand:hover .brand__name{ color:var(--blue); }

.utility-strip{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  margin:0;
  padding:0;
  list-style:none;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:rgba(36,31,27,.68);
}

.utility-strip__item{
  display:inline-flex;
  align-items:center;
  gap:7px;
  padding:4px 14px;
  border-left:1px solid var(--rule);
  white-space:nowrap;
}

.utility-strip__item:first-child{
  border-left:0;
  padding-left:0;
}

.utility-strip__item:last-child{ padding-right:0; }

.dot{
  display:inline-block;
  width:6px;
  height:6px;
  flex:none;
  background:var(--mist);
}

.dot--spring{ background:var(--spring); }
.dot--blue{ background:var(--blue); }
.dot--clay{ background:var(--clay); }
.dot--mist{ background:var(--mist); }

.site-header__main{
  position:relative;
  background:var(--paper);
  border-bottom:1px solid var(--ink);
}

.site-header__main-inner{
  display:flex;
  align-items:center;
  gap:20px;
  min-height:58px;
}

.primary-nav{
  position:relative;
  flex:1 1 auto;
  min-width:0;
}

.primary-nav__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:2px;
  margin:0;
  padding:0;
  list-style:none;
}

.nav-link{
  display:inline-block;
  padding:9px 14px;
  font-size:15px;
  font-weight:500;
  color:var(--ink);
  text-decoration:none;
  border-bottom:2px solid transparent;
  transition:color .18s ease, background-color .18s ease, border-color .18s ease;
}

.nav-link:hover{
  color:var(--blue);
  background:var(--light-cyan);
  border-bottom-color:var(--blue);
}

.nav-link[aria-current="page"]{
  font-weight:700;
  border-bottom-color:var(--clay);
  background:var(--light-clay);
}

.search-hint{
  display:inline-flex;
  align-items:center;
  gap:8px;
  max-width:260px;
  padding:8px 12px;
  border:1px solid var(--rule);
  color:rgba(36,31,27,.62);
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.04em;
  text-decoration:none;
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
  transition:color .18s ease, border-color .18s ease, background-color .18s ease;
}

.search-hint__glyph{
  color:var(--clay);
  font-weight:700;
}

.search-hint:hover{
  color:var(--blue);
  border-color:var(--blue);
  background:var(--light-cyan);
}

.header-cta{ white-space:nowrap; }

.nav-toggle{
  display:none;
  align-items:center;
  gap:10px;
  padding:9px 13px;
  background:var(--paper);
  border:1px solid var(--ink);
  color:var(--ink);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.12em;
  cursor:pointer;
  transition:background-color .18s ease;
}

.nav-toggle:hover{ background:var(--light-cyan); }

.nav-toggle__bars{
  display:grid;
  gap:4px;
  width:18px;
}

.nav-toggle__bars i{
  display:block;
  height:2px;
  background:currentColor;
  transition:transform .18s ease, opacity .18s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1){
  transform:translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2){
  opacity:0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3){
  transform:translateY(-6px) rotate(-45deg);
}

.nav-toggle__label{
  font-size:11.5px;
  line-height:1;
}

@keyframes nav-in{
  from{ opacity:0; transform:translateY(-6px); }
  to{ opacity:1; transform:none; }
}

@media (max-width:1180px){
  .search-hint{
    max-width:150px;
    font-size:11px;
  }
}

@media (max-width:1040px){
  .utility-strip{ display:none; }
  .site-header__top-inner{ min-height:auto; padding-block:12px; }
}

@media (max-width:900px){
  .brand__name{ font-size:21px; }
  .brand__descriptor{ font-size:10px; letter-spacing:.12em; }

  .site-header__main-inner{
    justify-content:space-between;
    gap:12px;
    min-height:54px;
  }

  .nav-toggle{ display:inline-flex; }
  .search-hint{ display:none; }

  .primary-nav{
    position:absolute;
    left:0;
    right:0;
    top:100%;
    display:none;
    flex:0 0 auto;
    background:var(--paper);
    border-bottom:1px solid var(--ink);
    box-shadow:0 6px 0 rgba(36,31,27,.06);
  }

  .primary-nav[data-open]{
    display:block;
    animation:nav-in .2s ease-out both;
  }

  .primary-nav__list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding:6px 0;
  }

  .primary-nav__list li{
    border-bottom:1px solid var(--rule);
  }

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

  .nav-link{
    display:block;
    padding:14px var(--gutter);
    border-bottom:0;
    border-left:3px solid transparent;
  }

  .nav-link[aria-current="page"]{
    background:var(--light-clay);
    border-left-color:var(--clay);
    border-bottom:0;
  }

  .header-cta{
    padding:9px 14px;
    font-size:13px;
    box-shadow:2px 2px 0 var(--ink);
  }
}

/* 8. 页脚
   ========================================================================== */
.site-footer{
  background:var(--deep);
  color:var(--cream);
  margin-top:0;
}

.site-footer__inner{
  display:grid;
  grid-template-columns:1.5fr .8fr .8fr 1.25fr;
  gap:40px;
  padding-block:56px 44px;
}

.site-footer__brand{
  display:flex;
  flex-direction:column;
  align-items:flex-start;
  gap:12px;
}

.site-footer__kicker{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.22em;
  color:var(--on-deep-soft);
}

.footer-brand{
  display:inline-block;
  font-size:30px;
  font-weight:900;
  letter-spacing:.08em;
  color:var(--cream);
  text-decoration:none;
  padding-bottom:4px;
  border-bottom:2px solid var(--clay);
  transition:color .18s ease, border-color .18s ease;
}

.footer-brand:hover{
  color:#FFFFFF;
  border-bottom-color:var(--spring);
}

.site-footer__desc{
  max-width:26em;
  font-size:14px;
  line-height:1.7;
  color:var(--on-deep);
}

.site-footer__stamp{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  color:var(--on-deep-soft);
}

.site-footer__col{ min-width:0; }

.site-footer__title{
  display:flex;
  align-items:center;
  gap:8px;
  margin-bottom:16px;
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:700;
  letter-spacing:.2em;
  color:var(--cream);
}

.site-footer__title::before{
  content:"";
  width:6px;
  height:6px;
  background:var(--clay);
  flex:none;
}

.site-footer__list{
  display:grid;
  gap:10px;
  margin:0;
  padding:0;
  list-style:none;
  font-size:14px;
}

.site-footer__link{
  display:inline-block;
  color:var(--on-deep);
  text-decoration:none;
  padding-bottom:2px;
  border-bottom:1px solid transparent;
  transition:color .18s ease, border-color .18s ease;
}

.site-footer__link:hover,
.site-footer__link:focus-visible{
  color:var(--cream);
  border-bottom-color:var(--clay);
}

.site-footer__link--sm{
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.08em;
}

.site-footer__contact-item{
  display:grid;
  grid-template-columns:46px minmax(0,1fr);
  gap:10px;
  font-size:13.5px;
  line-height:1.6;
  color:var(--on-deep);
  word-break:break-word;
}

.site-footer__k{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.1em;
  color:var(--on-deep-soft);
  padding-top:2px;
}

.site-footer__legal{
  border-top:1px solid rgba(247,241,230,.18);
}

.site-footer__legal-inner{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  padding-block:18px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:var(--on-deep-soft);
}

.site-footer__copy{ margin:0; }

.site-footer__legal-links{
  display:flex;
  flex-wrap:wrap;
  gap:18px;
  margin:0;
  padding:0;
  list-style:none;
}

@media (max-width:1040px){
  .site-footer__inner{
    grid-template-columns:1fr 1fr;
    gap:32px;
    padding-block:44px 32px;
  }
}

@media (max-width:640px){
  .site-footer__inner{
    grid-template-columns:minmax(0,1fr);
    padding-block:36px 24px;
  }
  .site-footer__legal-inner{
    flex-direction:column;
    align-items:flex-start;
  }
  .footer-brand{ font-size:25px; }
}

/* 9. 按钮
   ========================================================================== */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  padding:11px 20px;
  background:var(--paper);
  color:var(--ink);
  border:1px solid var(--ink);
  font-size:14px;
  font-weight:700;
  letter-spacing:.04em;
  line-height:1.3;
  text-decoration:none;
  cursor:pointer;
  transition:background-color .18s ease, color .18s ease, transform .12s ease, box-shadow .18s ease;
}

.btn--accent{
  background:var(--clay);
  color:var(--paper);
  box-shadow:var(--print-shadow);
}

.btn--accent:hover{
  background:#C25C22;
}

.btn--accent:active{
  transform:translate(2px,2px);
  box-shadow:1px 1px 0 var(--ink);
}

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

.btn--ghost:hover{
  background:var(--ink);
  color:var(--cream);
}

.btn--sm{
  padding:7px 14px;
  font-size:12.5px;
}

.btn--block{
  width:100%;
}

/* 10. 章节头 / 展签 / 正文
   ========================================================================== */
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.22em;
  text-transform:uppercase;
  color:var(--blue);
}

.eyebrow::before{
  content:"";
  width:22px;
  height:1px;
  background:currentColor;
  flex:none;
}

.section-head{
  display:flex;
  flex-wrap:wrap;
  align-items:flex-end;
  justify-content:space-between;
  gap:16px;
  padding-bottom:14px;
  margin-bottom:28px;
  border-bottom:1px solid var(--ink);
}

.section-head__title{
  font-size:clamp(24px,3vw,36px);
  font-weight:900;
  letter-spacing:-.015em;
  line-height:1.2;
}

.section-head__note{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:rgba(36,31,27,.6);
}

.annotation{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:rgba(36,31,27,.55);
}

.annotation--vertical{
  writing-mode:vertical-rl;
  text-orientation:mixed;
  letter-spacing:.28em;
}

.prose{
  max-width:72ch;
  font-size:16px;
  line-height:1.8;
}

.prose > * + *{ margin-top:1em; }

.prose h2{
  font-size:clamp(20px,2.4vw,28px);
  font-weight:900;
  margin-top:1.8em;
  padding-top:.6em;
  border-top:1px solid var(--rule);
}

.prose h3{
  font-size:18px;
  font-weight:700;
  margin-top:1.4em;
}

.prose ul,
.prose ol{
  padding-left:1.3em;
  list-style:disc;
}

.prose ol{ list-style:decimal; }

.prose li + li{ margin-top:.4em; }

.prose a{
  color:var(--blue);
  text-decoration:underline;
  text-underline-offset:3px;
}

.prose a:hover{ color:var(--clay); }

.prose strong{ font-weight:700; }

/* 11. 面板卡片
   ========================================================================== */
.panel{
  position:relative;
  display:flex;
  flex-direction:column;
  gap:10px;
  padding:22px;
  background:var(--paper);
  border:1px solid var(--rule-strong);
  transition:border-color .18s ease, transform .18s ease;
}

.panel--accent{
  border-left:4px solid var(--clay);
}

.panel--deep{
  background:var(--deep);
  color:var(--cream);
  border-color:var(--deep);
}

.panel__label{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  color:var(--blue);
}

.panel__title{
  font-size:20px;
  font-weight:700;
  line-height:1.35;
}

.panel__text{
  font-size:14.5px;
  line-height:1.7;
  color:rgba(36,31,27,.78);
}

.panel--deep .panel__label{ color:var(--spring); }
.panel--deep .panel__title{ color:var(--cream); }
.panel--deep .panel__text{ color:var(--on-deep); }

/* 12. 标签
   ========================================================================== */
.tag-wall{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
}

.tag{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:5px 10px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.05em;
  line-height:1.5;
  color:var(--ink);
  text-decoration:none;
  background:var(--paper);
  border:1px solid var(--rule-strong);
  transition:background-color .18s ease, border-color .18s ease, color .18s ease;
}

.tag::before{
  content:"";
  width:5px;
  height:5px;
  flex:none;
  background:currentColor;
}

.tag--spring{
  background:var(--light-cyan);
  border-color:var(--spring);
  color:#2C5A48;
}

.tag--blue{
  background:rgba(46,111,142,.12);
  border-color:var(--blue);
  color:var(--blue);
}

.tag--clay{
  background:var(--light-clay);
  border-color:var(--clay);
  color:#8F431A;
}

.tag--mist{
  background:rgba(200,197,189,.32);
  border-color:var(--mist);
  color:rgba(36,31,27,.72);
}

.tag:hover{
  border-color:var(--ink);
  color:var(--ink);
  background:var(--paper);
}

/* 13. 标签页 / 分段切换
   ========================================================================== */
.tabset{
  display:block;
}

.tabset__list{
  display:flex;
  flex-wrap:wrap;
  gap:0;
  background:var(--paper);
  border:1px solid var(--rule-strong);
  border-bottom:0;
  overflow-x:auto;
}

.tabset__tab{
  appearance:none;
  padding:12px 18px;
  background:transparent;
  border:0;
  border-right:1px solid var(--rule);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.1em;
  color:rgba(36,31,27,.68);
  cursor:pointer;
  white-space:nowrap;
  transition:background-color .16s ease, color .16s ease;
}

.tabset__tab:last-child{ border-right:0; }

.tabset__tab:hover{
  background:var(--light-cyan);
  color:var(--ink);
}

.tabset__tab[aria-selected="true"]{
  background:var(--ink);
  color:var(--paper);
}

.tabset__panel{
  padding:24px;
  background:var(--paper);
  border:1px solid var(--rule-strong);
  animation:panel-in .18s ease-out both;
}

.tabset__panel[hidden]{
  display:none;
}

@keyframes panel-in{
  from{ opacity:0; transform:translateY(6px); }
  to{ opacity:1; transform:none; }
}

/* 14. 面包屑
   ========================================================================== */
.breadcrumbs{
  padding-block:16px;
  border-bottom:1px solid var(--rule);
}

.breadcrumbs__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  margin:0;
  padding:0;
  list-style:none;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.08em;
}

.breadcrumbs__item{
  color:rgba(36,31,27,.6);
}

.breadcrumbs__item[aria-current="page"]{
  color:var(--ink);
  font-weight:700;
}

.breadcrumbs__link{
  color:var(--blue);
  text-decoration:none;
  border-bottom:1px solid transparent;
}

.breadcrumbs__link:hover{
  border-bottom-color:var(--blue);
}

.breadcrumbs__sep{
  color:var(--mist);
}

/* 15. 图片容器基础规则
   ========================================================================== */
.media-frame{
  position:relative;
  display:block;
  width:100%;
  overflow:hidden;
  aspect-ratio:16 / 9;
  background:var(--light-cyan);
  border:1px solid var(--rule-strong);
}

.media-frame--square{ aspect-ratio:1 / 1; }
.media-frame--portrait{ aspect-ratio:3 / 4; }
.media-frame--wide{ aspect-ratio:21 / 9; }

.media-frame__img{
  display:block;
  width:100%;
  height:100%;
  object-fit:cover;
}

.media-frame__caption{
  margin-top:8px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  color:rgba(36,31,27,.6);
}

/* 16. 动效降级
   ========================================================================== */
@media (prefers-reduced-motion:reduce){
  html{ scroll-behavior:auto; }

  *,
  *::before,
  *::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }

  .has-js [data-reveal]{
    opacity:1;
    transform:none;
  }

  .primary-nav[data-open],
  .tabset__panel{
    animation:none;
  }
}