/* ============================================================
   四季官网 · 共享样式 /assets/site.css
   纸底奶油 · 深棕黑 · 印章红橙 · 四季轮转主色
   ============================================================ */

/* ---------- 1. 变量 ---------- */
:root{
  --paper:#F4EFE6;
  --paper-2:#EDE6D9;
  --paper-3:#E3D9C7;
  --ink:#1E1A16;
  --ink-soft:#5A5049;
  --line:#D8D0C4;
  --seal:#C2452D;

  --spring:#7FA07A;
  --spring-2:#E8C4C4;
  --summer:#1F4E4A;
  --summer-2:#E8B93C;
  --autumn:#C0603A;
  --autumn-2:#D9B26A;
  --winter:#8FA6B8;
  --winter-2:#4A4A4A;

  --season:#7FA07A;
  --season-2:#E8C4C4;
  --season-on:#1E1A16;

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

  --shadow-hard:6px 6px 0 var(--ink);
  --shadow-soft:3px 3px 0 var(--ink);

  --header-h:68px;
  --wrap:1240px;
  --gutter:clamp(16px,4vw,48px);
}

[data-season="spring"]{--season:#7FA07A;--season-2:#E8C4C4;--season-on:#1E1A16;}
[data-season="summer"]{--season:#1F4E4A;--season-2:#E8B93C;--season-on:#F4EFE6;}
[data-season="autumn"]{--season:#C0603A;--season-2:#D9B26A;--season-on:#F4EFE6;}
[data-season="winter"]{--season:#8FA6B8;--season-2:#4A4A4A;--season-on:#1E1A16;}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box;}
html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:calc(var(--header-h) + 20px);
}
body{
  margin:0;
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  color:var(--ink);
  background-color:var(--paper);
  background-image:radial-gradient(rgba(30,26,22,.055) 1px,transparent 1px);
  background-size:4px 4px;
}
img,svg,video{display:block;max-width:100%;}
a{color:inherit;}
button{font:inherit;color:inherit;}
ul,ol{margin:0;padding:0;list-style:none;}
h1,h2,h3,h4,h5,h6,p,figure,blockquote{margin:0;}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:800;line-height:1.24;letter-spacing:-.01em;}
h1{font-size:clamp(30px,5.4vw,64px);}
h2{font-size:clamp(24px,3.2vw,32px);}
h3{font-size:clamp(19px,2.2vw,24px);}
h4{font-size:clamp(17px,1.8vw,19px);}

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

/* ---------- 3. 容器 / 栅格 ---------- */
.wrap{width:100%;max-width:var(--wrap);margin:0 auto;padding:0 var(--gutter);}
.wrap--narrow{max-width:860px;}

.split{
  display:grid;
  grid-template-columns:minmax(0,34%) minmax(0,1fr);
  gap:clamp(24px,3.5vw,56px);
  align-items:start;
}
.rail{position:sticky;top:calc(var(--header-h) + 18px);align-self:start;}

.grid-2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:clamp(18px,2.4vw,32px);}
.grid-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(18px,2.4vw,32px);}
.grid-4{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:clamp(16px,2vw,28px);}

.stagger{display:grid;gap:clamp(20px,3vw,40px);padding-bottom:clamp(20px,4vw,72px);}
.stagger > *:nth-child(even){margin-top:clamp(20px,4vw,72px);}

/* ---------- 4. 跳过链接 ---------- */
.skip-link{
  position:absolute;
  left:12px;top:-120px;
  z-index:200;
  padding:10px 18px;
  background:var(--ink);
  color:var(--paper);
  font-size:14px;
  letter-spacing:.04em;
  text-decoration:none;
  border:2px solid var(--paper);
  transition:top .18s ease;
}
.skip-link:focus{top:12px;}

/* ---------- 5. 页头 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:90;
  background:var(--paper);
  border-bottom:2px solid var(--ink);
}

/* 顶部信息带 */
.header-strip{
  background:var(--ink);
  color:var(--paper);
  overflow:hidden;
  max-height:48px;
  transition:max-height .28s ease,opacity .22s ease;
}
.header-strip.is-collapsed{max-height:0;opacity:0;}
.header-strip__inner{
  max-width:var(--wrap);
  margin:0 auto;
  padding:7px var(--gutter);
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.12em;
}
.header-strip__note{display:flex;align-items:center;gap:9px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
.header-strip__dot{
  flex:0 0 auto;
  width:7px;height:7px;border-radius:50%;
  background:var(--season);
}
.header-strip__stamp{
  flex:0 0 auto;
  border:1.5px solid rgba(244,239,230,.75);
  padding:1px 8px;
  font-size:11px;
  transform:rotate(-1.5deg);
}

/* 命令栏 */
.header-bar{
  max-width:var(--wrap);
  margin:0 auto;
  padding:0 var(--gutter);
  min-height:var(--header-h);
  display:grid;
  grid-template-columns:auto minmax(0,1fr) auto;
  align-items:center;
  gap:clamp(10px,2vw,28px);
}

.brand{
  display:flex;
  align-items:center;
  gap:11px;
  padding:8px 0;
  min-width:0;
  text-decoration:none;
}
.brand__seal{
  flex:0 0 auto;
  width:36px;height:36px;
  display:grid;
  grid-template-columns:1fr 1fr;
  place-items:center;
  background:var(--seal);
  color:var(--paper);
  border:2px solid var(--ink);
  box-shadow:3px 3px 0 var(--ink);
  font-family:var(--font-display);
  font-weight:800;
  font-size:13px;
  line-height:1;
  transform:rotate(-2deg);
  transition:transform .22s ease,box-shadow .22s ease;
}
.brand:hover .brand__seal{transform:rotate(1.5deg);box-shadow:4px 4px 0 var(--ink);}
.brand__meta{display:flex;flex-direction:column;gap:3px;min-width:0;}
.brand__name{
  font-family:var(--font-display);
  font-weight:800;
  font-size:17px;
  letter-spacing:.1em;
  line-height:1.1;
  white-space:nowrap;
}
.brand__season{
  display:flex;
  align-items:center;
  gap:6px;
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.18em;
  color:var(--ink-soft);
  line-height:1;
}
.brand__season-tag{
  writing-mode:vertical-rl;
  text-orientation:upright;
  background:var(--season);
  color:var(--season-on);
  border:1.5px solid var(--ink);
  padding:1px;
  font-size:10px;
  line-height:1;
  letter-spacing:0;
}

/* 导航 */
.nav{display:block;min-width:0;}
.nav__list{
  display:flex;
  align-items:center;
  justify-content:center;
  flex-wrap:wrap;
  gap:clamp(2px,1vw,14px);
}
.nav__item{flex:0 0 auto;}
.nav__link{
  position:relative;
  display:inline-flex;
  align-items:baseline;
  gap:5px;
  padding:9px 7px;
  color:var(--ink);
  font-size:14.5px;
  font-weight:500;
  letter-spacing:.02em;
  text-decoration:none;
  border-bottom:2px solid transparent;
  transition:border-color .18s ease,color .18s ease;
}
.nav__link:hover{border-bottom-color:var(--season);}
.nav__idx{
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.04em;
  color:var(--ink-soft);
}
.nav__link[aria-current="page"]{font-weight:700;}
.nav__link[aria-current="page"] .nav__idx{color:var(--seal);}
.nav__link[aria-current="page"]::after{
  content:"";
  position:absolute;
  right:0;top:7px;
  width:6px;height:6px;
  border-radius:50%;
  background:var(--seal);
}

.header-actions{display:flex;align-items:center;gap:10px;}

.nav-toggle{
  display:none;
  align-items:center;
  gap:8px;
  padding:8px 12px;
  background:var(--paper);
  border:2px solid var(--ink);
  box-shadow:3px 3px 0 var(--ink);
  font-size:13px;
  font-weight:600;
  letter-spacing:.08em;
  cursor:pointer;
  transition:background-color .18s ease,color .18s ease,transform .16s ease,box-shadow .16s ease;
}
.nav-toggle:active{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--ink);}
.nav-toggle__icon{
  position:relative;
  display:block;
  width:16px;height:11px;
  border-top:2px solid var(--ink);
  border-bottom:2px solid var(--ink);
}
.nav-toggle__icon::after{
  content:"";
  position:absolute;
  left:0;right:0;top:50%;
  height:2px;
  background:var(--ink);
  transform:translateY(-50%);
}
.nav-toggle[aria-expanded="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink);}
.nav-toggle[aria-expanded="true"] .nav-toggle__icon{border-color:var(--paper);}
.nav-toggle[aria-expanded="true"] .nav-toggle__icon::after{background:var(--paper);}

/* 滚动进度 */
.scroll-progress{
  position:absolute;
  left:0;right:0;bottom:0;
  height:3px;
  overflow:hidden;
  pointer-events:none;
}
.scroll-progress__bar{
  display:block;
  height:100%;
  width:0;
  background:var(--seal);
}

/* ---------- 6. 页脚 ---------- */
.site-footer{
  margin-top:clamp(48px,7vw,110px);
  background:var(--ink);
  color:var(--paper);
}
.footer__stripe{
  height:10px;
  background:linear-gradient(90deg,
    var(--spring) 0 25%,
    var(--summer) 25% 50%,
    var(--autumn) 50% 75%,
    var(--winter) 75% 100%);
}
.footer__inner{
  max-width:var(--wrap);
  margin:0 auto;
  padding:clamp(36px,5vw,64px) var(--gutter) clamp(24px,3vw,38px);
  display:grid;
  grid-template-columns:1.3fr .9fr 1.15fr 1fr;
  gap:clamp(24px,3vw,48px);
}
.footer__col{min-width:0;}
.footer__wordmark{
  font-family:var(--font-display);
  font-weight:800;
  font-size:27px;
  letter-spacing:.16em;
  line-height:1.2;
}
.footer__tagline{
  margin-top:6px;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.26em;
  color:rgba(244,239,230,.6);
}
.footer__note{
  margin-top:14px;
  max-width:24ch;
  font-size:13.5px;
  line-height:1.7;
  color:rgba(244,239,230,.55);
}
.footer__title{
  margin-bottom:14px;
  font-family:var(--font-mono);
  font-size:11px;
  font-weight:500;
  letter-spacing:.22em;
  color:rgba(244,239,230,.5);
}
.footer__list{display:flex;flex-direction:column;gap:9px;}
.footer__list a{
  display:inline-block;
  font-size:14.5px;
  color:rgba(244,239,230,.86);
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .18s ease,border-color .18s ease;
}
.footer__list a:hover{color:var(--paper);border-bottom-color:var(--seal);}
.footer__row{
  display:flex;
  gap:12px;
  margin-bottom:9px;
  font-size:13.5px;
  line-height:1.6;
}
.footer__key{
  flex:0 0 62px;
  font-size:12.5px;
  color:rgba(244,239,230,.5);
  padding-top:1px;
}
.footer__val{
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.01em;
  word-break:break-all;
  color:rgba(244,239,230,.92);
}
.footer__addr{
  font-size:14px;
  line-height:1.9;
  color:rgba(244,239,230,.82);
}
.footer__cta{margin-top:16px;}
.site-footer .btn--seal{
  border-color:var(--seal);
  box-shadow:4px 4px 0 rgba(244,239,230,.24);
}
.site-footer .btn--seal:hover{
  box-shadow:1px 1px 0 rgba(244,239,230,.24);
}
.footer__base{
  max-width:var(--wrap);
  margin:0 auto;
  padding:18px var(--gutter) 30px;
  border-top:1px solid rgba(244,239,230,.18);
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:rgba(244,239,230,.58);
}
.footer__meta{margin:0;}
.footer__legal{display:flex;flex-wrap:wrap;gap:18px;}
.footer__legal a{
  color:rgba(244,239,230,.78);
  text-decoration:none;
  border-bottom:1px solid rgba(244,239,230,.25);
  transition:color .18s ease,border-color .18s ease;
}
.footer__legal a:hover{color:var(--paper);border-bottom-color:var(--seal);}

/* ---------- 7. 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:10px 18px;
  background:var(--paper);
  color:var(--ink);
  border:2px solid var(--ink);
  box-shadow:var(--shadow-soft);
  font-family:var(--font-body);
  font-size:14px;
  font-weight:600;
  letter-spacing:.04em;
  text-decoration:none;
  cursor:pointer;
  transition:transform .16s ease,box-shadow .16s ease,background-color .16s ease,color .16s ease;
}
.btn:hover{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--ink);}
.btn:active{transform:translate(3px,3px);box-shadow:none;}
.btn--seal{background:var(--seal);color:var(--paper);}
.btn--season{background:var(--season);color:var(--season-on);}
.btn--ghost{background:transparent;box-shadow:none;}
.btn--ghost:hover{transform:none;background:var(--season-2);}
.btn--sm{padding:7px 13px;font-size:13px;}
.btn--block{width:100%;}
.btn-row{display:flex;flex-wrap:wrap;gap:12px;}

/* ---------- 8. 章节编号 / 分隔 ---------- */
.section-head{
  display:flex;
  align-items:flex-start;
  gap:16px;
  margin-bottom:clamp(18px,2.4vw,30px);
}
.section-head__num{
  flex:0 0 auto;
  padding:3px 9px;
  background:var(--season);
  color:var(--season-on);
  border:2px solid var(--ink);
  box-shadow:3px 3px 0 var(--ink);
  font-family:var(--font-mono);
  font-size:13px;
  font-weight:500;
  letter-spacing:.08em;
  line-height:1.6;
}
.section-head__body{min-width:0;}
.section-head__title{
  font-family:var(--font-display);
  font-size:clamp(20px,2.6vw,30px);
  font-weight:800;
  line-height:1.3;
}
.section-head__desc{
  margin-top:6px;
  font-size:14.5px;
  color:var(--ink-soft);
}
.kicker{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.2em;
  color:var(--ink-soft);
}
.rule{height:2px;background:var(--ink);border:0;margin:clamp(24px,3vw,40px) 0;}
.rule--season{background:var(--season);}
.rule--line{background:var(--line);height:1px;}

/* ---------- 9. 印章 / 图例 / 标签 ---------- */
.stamp{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  padding:4px 9px;
  background:rgba(194,69,45,.07);
  color:var(--seal);
  border:2px solid var(--seal);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.14em;
  transform:rotate(-2deg);
  transition:transform .22s ease,box-shadow .22s ease;
}
.stamp:hover{transform:rotate(1.5deg);box-shadow:2px 2px 0 var(--seal);}
.stamp--seal{
  writing-mode:vertical-rl;
  text-orientation:upright;
  padding:9px 5px;
  letter-spacing:.12em;
  transform:rotate(-1.5deg);
}

.legend{
  display:flex;
  flex-wrap:wrap;
  gap:10px 22px;
  padding:14px 16px;
  background:var(--paper-2);
  border:2px solid var(--ink);
  box-shadow:var(--shadow-soft);
}
.legend__item{
  display:flex;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.02em;
}
.legend__swatch{
  flex:0 0 auto;
  width:14px;height:14px;
  border:1.5px solid var(--ink);
}
.legend__swatch--spring{background:var(--spring);}
.legend__swatch--summer{background:var(--summer);}
.legend__swatch--autumn{background:var(--autumn);}
.legend__swatch--winter{background:var(--winter);}
.legend__swatch--seal{background:var(--seal);}
.legend__swatch--line{background:var(--line);}

.tag{
  display:inline-flex;
  align-items:center;
  gap:5px;
  padding:2px 8px;
  background:var(--paper);
  border:1.5px solid var(--ink);
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
}

/* ---------- 10. 筛选 ---------- */
.filter-bar{display:flex;flex-wrap:wrap;gap:8px;}
.filter-btn{
  padding:6px 13px;
  background:var(--paper);
  color:var(--ink);
  border:2px solid var(--ink);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  cursor:pointer;
  transition:background-color .16s ease,color .16s ease,transform .16s ease;
}
.filter-btn:hover{background:var(--season-2);}
.filter-btn.is-active{
  background:var(--season);
  color:var(--season-on);
}
[data-filter-item].is-filtered-out{display:none;}

/* ---------- 11. 表格 ---------- */
.table-wrap{
  overflow-x:auto;
  background:var(--paper);
  border:2px solid var(--ink);
  box-shadow:var(--shadow-soft);
}
.table{
  width:100%;
  min-width:560px;
  border-collapse:collapse;
  font-size:15px;
}
.table th,.table td{
  padding:12px 16px;
  text-align:left;
  vertical-align:top;
  border-bottom:1px solid var(--line);
}
.table thead th{
  background:var(--season);
  color:var(--season-on);
  border-bottom:2px solid var(--ink);
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:500;
  letter-spacing:.1em;
}
.table tbody tr:last-child td{border-bottom:0;}
.table .num{
  font-family:var(--font-mono);
  text-align:right;
  letter-spacing:.02em;
}

/* ---------- 12. 图片容器 ---------- */
.figure{
  position:relative;
  margin:0;
  background:var(--paper-2);
  border:2px solid var(--ink);
  box-shadow:var(--shadow-hard);
  overflow:hidden;
}
.figure__media{
  position:relative;
  display:block;
  width:100%;
  overflow:hidden;
  background:linear-gradient(135deg,var(--season-2),var(--paper-2));
}
.figure__media::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background:repeating-linear-gradient(45deg,rgba(30,26,22,.05) 0 10px,transparent 10px 20px);
}
.figure__media > img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.figure__caption{
  display:flex;
  justify-content:space-between;
  gap:12px;
  padding:10px 14px;
  background:var(--paper);
  border-top:2px solid var(--ink);
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:var(--ink-soft);
}
.ratio-1-1{aspect-ratio:1/1;}
.ratio-4-3{aspect-ratio:4/3;}
.ratio-3-4{aspect-ratio:3/4;}
.ratio-16-9{aspect-ratio:16/9;}
.ratio-21-9{aspect-ratio:21/9;}

/* ---------- 13. 正文 / 索引链接 ---------- */
.prose{max-width:68ch;}
.prose p{margin-bottom:1.1em;}
.prose p:last-child{margin-bottom:0;}
.prose h2,.prose h3{margin:2em 0 .7em;}
.prose ul{list-style:square;padding-left:1.2em;margin-bottom:1.1em;}
.prose li{margin-bottom:.4em;}
.prose strong{font-weight:700;}

.spy-link{
  display:flex;
  align-items:baseline;
  gap:10px;
  padding:9px 12px;
  color:var(--ink-soft);
  border-left:2px solid var(--line);
  font-size:14px;
  text-decoration:none;
  transition:color .18s ease,border-color .18s ease,background-color .18s ease;
}
.spy-link:hover{color:var(--ink);border-left-color:var(--season);}
.spy-link.is-current{
  color:var(--ink);
  font-weight:700;
  border-left-color:var(--seal);
  background:rgba(194,69,45,.07);
}

/* ---------- 14. 显现动效 ---------- */
[data-reveal]{
  opacity:0;
  transform:translateY(14px);
  transition:opacity .42s ease,transform .42s ease;
}
[data-reveal].is-revealed{opacity:1;transform:none;}

/* ---------- 15. 响应式 ---------- */
@media (max-width:1080px){
  .footer__inner{grid-template-columns:1fr 1fr;}
  .grid-4{grid-template-columns:repeat(2,minmax(0,1fr));}
}

@media (max-width:980px){
  :root{--header-h:62px;}

  .nav-toggle{display:inline-flex;}
  .header-cta{display:none;}

  .nav{
    position:absolute;
    left:0;right:0;top:100%;
    display:none;
    padding:4px var(--gutter) 24px;
    background:var(--paper);
    border-bottom:2px solid var(--ink);
    box-shadow:0 8px 0 rgba(30,26,22,.1);
    max-height:calc(100vh - var(--header-h));
    overflow-y:auto;
  }
  .nav[data-open]{display:block;}
  .nav__list{flex-direction:column;align-items:stretch;flex-wrap:nowrap;gap:0;}
  .nav__item{border-bottom:1px solid var(--line);}
  .nav__item:last-child{border-bottom:0;}
  .nav__link{
    display:flex;
    justify-content:flex-start;
    padding:15px 2px;
    font-size:16.5px;
    border-bottom:0;
  }
  .nav__link::after{display:none;}
  .nav__link[aria-current="page"]{color:var(--seal);}
  .nav__link[aria-current="page"] .nav__idx{color:var(--seal);}

  .split{grid-template-columns:minmax(0,1fr);}
  .rail{position:static;top:auto;}
}

@media (max-width:820px){
  .grid-2,.grid-3{grid-template-columns:minmax(0,1fr);}
}

@media (max-width:620px){
  .footer__inner{grid-template-columns:1fr;gap:30px;}
  .footer__base{flex-direction:column;align-items:flex-start;gap:8px;}
  .stagger > *:nth-child(even){margin-top:0;}
  .grid-4{grid-template-columns:minmax(0,1fr);}
  .header-strip__note{font-size:11px;letter-spacing:.08em;}
}

/* ---------- 16. 降低动效 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  [data-reveal]{opacity:1;transform:none;transition:none;}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
}