/* =========================================================
   四季 · /assets/site.css
   共享外壳：重置 / 变量 / 中文排版 / 头部 / 页脚 / 基础组件
   ========================================================= */

/* ---------- 1. 重置 ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%}
body{margin:0}
img,svg,video,canvas{display:block;max-width:100%;height:auto}
ul,ol{margin:0;padding:0;list-style:none}
h1,h2,h3,h4,h5,p,figure,blockquote{margin:0}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;padding:0;cursor:pointer}
table{border-collapse:collapse;width:100%}
hr{border:0;border-top:1px solid var(--rule);margin:0}
main:focus{outline:none}
:focus-visible{outline:2px solid var(--ember);outline-offset:3px}
::selection{background:rgba(217,102,46,.24)}

/* ---------- 2. 变量 ---------- */
:root{
  --ink:#14161A;
  --paper:#F7F3EA;
  --paper-2:#EFE8DA;
  --char:#2B2B2B;
  --char-soft:#4A4A48;
  --char-mute:#5C5B57;

  --celadon:#6E9C8A;
  --sprout:#C9B458;
  --deep-sea:#1F4E6B;
  --ember:#D9662E;
  --maple:#A83A2E;
  --amber:#C58A34;
  --frost:#E4E8EC;
  --ink-blue:#2C3A4B;

  --accent:var(--celadon);
  --accent-deep:#3F6B5A;
  --accent-2:var(--sprout);
  --accent-cta:#A8441A;

  --rule:rgba(20,22,26,.13);
  --rule-soft:rgba(20,22,26,.07);
  --rule-strong:rgba(20,22,26,.26);
  --line-dark:rgba(247,243,234,.14);

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

  --rail:96px;
  --gutter:20px;
  --ease:cubic-bezier(.22,.61,.36,1);
  --s1:8px; --s2:16px; --s3:24px; --s4:48px; --s5:96px;
}
@media (min-width:768px){:root{--gutter:32px}}
@media (min-width:1024px){:root{--gutter:56px}}

/* 季节主题：任何区块加 data-season 或 .season-* 即可切换强调色 */
[data-season="spring"],.season-spring{--accent:var(--celadon);--accent-deep:#3F6B5A;--accent-2:var(--sprout);--accent-cta:#3F6B5A}
[data-season="summer"],.season-summer{--accent:var(--deep-sea);--accent-deep:#173B52;--accent-2:var(--ember);--accent-cta:#173B52}
[data-season="autumn"],.season-autumn{--accent:var(--maple);--accent-deep:#7E2A21;--accent-2:var(--amber);--accent-cta:#8E3226}
[data-season="winter"],.season-winter{--accent:var(--ink-blue);--accent-deep:#1B2532;--accent-2:var(--frost);--accent-cta:#1B2532}

/* ---------- 3. 中文排版 ---------- */
body{
  background:var(--paper);
  color:var(--char);
  font-family:var(--sans);
  font-size:16px;
  line-height:1.8;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
}
@media (min-width:1024px){body{padding-left:var(--rail)}}

h1,h2,h3,h4{font-family:var(--serif);font-weight:700;color:var(--ink);line-height:1.24}
h1{font-size:clamp(2rem,5vw,3.4rem);line-height:1.16;max-width:22em}
h2{font-size:clamp(1.5rem,3.2vw,2.4rem);max-width:22em}
h3{font-size:clamp(1.12rem,2vw,1.5rem);line-height:1.44;max-width:24em}
h4{font-size:1.02rem;line-height:1.5}
p{max-width:38em}
strong{font-weight:700;color:var(--ink)}
.lede{font-size:17px;line-height:1.9;color:var(--char-soft);max-width:38em}
.note{font-size:12.5px;line-height:1.8;letter-spacing:.08em;color:var(--char-mute);max-width:34em}
.vertical-note{writing-mode:vertical-rl;text-orientation:upright;font-size:12px;letter-spacing:.24em;color:var(--char-mute)}
.eyebrow{font-family:var(--mono);font-size:12px;letter-spacing:.22em;color:var(--accent-deep);text-transform:uppercase}
.num,.mono{font-family:var(--mono);font-weight:600;letter-spacing:.02em}
.visually-hidden{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}

/* ---------- 4. 布局容器与网格 ---------- */
.wrap{width:min(calc(100% - var(--gutter)*2),1360px);margin-inline:auto}
.wrap--narrow{width:min(calc(100% - var(--gutter)*2),880px);margin-inline:auto}
.section{padding:56px 0}
@media (min-width:768px){.section{padding:80px 0}}
@media (min-width:1024px){.section{padding:112px 0}}
.section--tight{padding:32px 0}
@media (min-width:1024px){.section--tight{padding:48px 0}}
.section--paper2{background:var(--paper-2);border-top:1px solid var(--rule-soft);border-bottom:1px solid var(--rule-soft)}
.section--dark{background:var(--ink);color:rgba(247,243,234,.82)}
.section--dark h1,.section--dark h2,.section--dark h3,.section--dark h4{color:var(--paper)}
.section--dark p{color:rgba(247,243,234,.8)}
.section--dark .lede{color:rgba(247,243,234,.82)}
.section--dark .note{color:rgba(247,243,234,.6)}
.section--dark .eyebrow{color:var(--accent-2)}

.section-head{display:flex;flex-direction:column;gap:12px;margin-bottom:32px}
@media (min-width:1024px){.section-head{margin-bottom:48px}}

.grid{display:grid;gap:var(--s3)}
.grid--2{display:grid;gap:var(--s3);grid-template-columns:1fr}
@media (min-width:768px){.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}}

.grid-editorial{display:grid;gap:var(--s3);grid-template-columns:1fr}
@media (min-width:900px){
  .grid-editorial{grid-template-columns:repeat(12,minmax(0,1fr));column-gap:var(--s3)}
  .col-note{grid-column:1/4}
  .col-main{grid-column:5/12}
  .col-wide{grid-column:4/12}
  .col-aside{grid-column:10/13}
  .col-full{grid-column:1/13}
}

/* ---------- 5. 按钮与行动组 ---------- */
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:14px 26px;border:1px solid transparent;border-radius:999px;
  font-size:15px;line-height:1.2;letter-spacing:.08em;
  transition:background-color .3s var(--ease),color .3s var(--ease),border-color .3s var(--ease),transform .3s var(--ease);
}
.btn:hover{transform:translateY(-1px)}
.btn--primary{background:var(--accent-cta);color:#FFF7EE}
.btn--primary:hover{background:var(--ink);color:var(--paper)}
.btn--outline{border-color:var(--rule-strong);color:var(--ink)}
.btn--outline:hover{background:var(--ink);border-color:var(--ink);color:var(--paper)}
.btn--ghost{border-color:rgba(247,243,234,.34);color:var(--paper)}
.btn--ghost:hover{background:var(--paper);border-color:var(--paper);color:var(--ink)}
.cta-row{display:flex;flex-wrap:wrap;gap:14px;align-items:center}

/* ---------- 6. 面包屑 ---------- */
.crumbs{display:flex;flex-wrap:wrap;align-items:center;gap:10px;font-size:12px;letter-spacing:.14em;color:var(--char-mute)}
.crumbs__item{color:var(--char-mute)}
a.crumbs__item:hover{color:var(--ink);border-bottom:1px solid var(--accent-2)}
.crumbs__item[aria-current="page"]{color:var(--ink)}
.crumbs__sep{color:rgba(20,22,26,.28)}

/* ---------- 7. 图片与纹理容器 ---------- */
.figure{display:flex;flex-direction:column;gap:12px;margin:0}
.figure__frame{
  position:relative;overflow:hidden;border-radius:8px;
  background:var(--paper-2);aspect-ratio:4/3;
}
.figure__frame img,.figure__frame svg{width:100%;height:100%;object-fit:cover}
.figure__frame--wide{aspect-ratio:16/9}
.figure__frame--tall{aspect-ratio:2/3}
.figure__frame--square{aspect-ratio:1/1}
.figure__frame--bleed{border-radius:0}
.figure__frame--soft{border-radius:28px 8px 28px 8px}
.figure__caption{font-size:12px;letter-spacing:.08em;line-height:1.75;color:var(--char-mute);max-width:36em}
.texture{position:relative;overflow:hidden;background:var(--paper-2)}
.texture::after{
  content:"";position:absolute;inset:0;pointer-events:none;mix-blend-mode:soft-light;
  background-image:repeating-linear-gradient(115deg,rgba(255,255,255,.12) 0 2px,rgba(0,0,0,0) 2px 7px);
}
.texture--spring{background:linear-gradient(150deg,#DCE8E0 0%,var(--celadon) 100%)}
.texture--summer{background:linear-gradient(150deg,var(--deep-sea) 0%,var(--ember) 100%)}
.texture--autumn{background:linear-gradient(150deg,var(--amber) 0%,var(--maple) 100%)}
.texture--winter{background:linear-gradient(150deg,var(--frost) 0%,var(--ink-blue) 100%)}

/* ---------- 8. 标签与刻度 ---------- */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:5px 13px;border:1px solid var(--rule);border-radius:999px;
  background:var(--paper-2);font-size:12px;letter-spacing:.12em;color:var(--char-soft);
}
.tag--accent{background:var(--accent-deep);border-color:transparent;color:#FFF7EE}
.stat{display:flex;flex-direction:column;gap:4px}
.stat__num{font-family:var(--mono);font-weight:600;font-size:clamp(1.5rem,3vw,2.2rem);line-height:1.1;color:var(--accent-deep)}
.stat__label{font-size:12px;letter-spacing:.14em;color:var(--char-mute)}

/* ---------- 9. 标签页与折叠层 ---------- */
.tabs{display:flex;flex-direction:column;gap:var(--s3)}
.tabs__list{display:flex;flex-wrap:wrap;gap:4px;border-bottom:1px solid var(--rule)}
.tabs__tab{
  padding:12px 18px;border-bottom:2px solid transparent;
  font-size:14px;letter-spacing:.1em;color:var(--char-mute);
  transition:color .3s var(--ease),border-color .3s var(--ease);
}
.tabs__tab:hover{color:var(--ink)}
.tabs__tab[aria-selected="true"]{color:var(--ink);font-weight:600;border-color:var(--accent-cta)}
.tabs__panel{padding-top:4px}
.tabs__panel[hidden]{display:none}

.fold{border-top:1px solid var(--rule);padding:2px 0}
.fold__summary{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:18px 0;cursor:pointer;list-style:none;
  font-family:var(--serif);font-size:17px;line-height:1.5;color:var(--ink);
}
.fold__summary::-webkit-details-marker{display:none}
.fold__summary::after{content:"＋";font-family:var(--mono);font-size:14px;color:var(--accent-deep)}
.fold[open] .fold__summary::after{content:"－"}
.fold__body{padding:0 0 22px;font-size:15px;line-height:1.9;color:var(--char-soft)}

/* ---------- 10. 头部外壳 ---------- */
.site-header{position:relative;z-index:60}
.skip-link{
  position:absolute;left:16px;top:-72px;z-index:130;
  padding:12px 22px;border-radius:0 0 8px 8px;
  background:var(--ink);color:var(--paper);
  font-size:14px;letter-spacing:.1em;
  transition:top .24s var(--ease);
}
.skip-link:focus{top:0}

/* 移动端顶部条 */
.topbar{
  position:fixed;top:0;left:0;right:0;height:60px;z-index:95;
  display:flex;align-items:center;justify-content:space-between;
  padding:0 12px 0 var(--gutter);
  background:var(--ink);color:var(--paper);
  border-bottom:1px solid var(--line-dark);
}
.topbar__brand{
  display:flex;align-items:baseline;gap:10px;
  font-family:var(--serif);font-size:19px;letter-spacing:.2em;color:var(--paper);
}
.topbar__sub{font-family:var(--sans);font-size:10.5px;letter-spacing:.16em;color:rgba(247,243,234,.5)}
@media (max-width:420px){.topbar__sub{display:none}}

.nav-toggle{
  display:flex;align-items:center;gap:10px;
  padding:10px 14px;border:1px solid rgba(247,243,234,.26);border-radius:999px;
  color:var(--paper);
  transition:background-color .3s var(--ease),border-color .3s var(--ease);
}
.nav-toggle:hover{background:rgba(247,243,234,.08)}
.nav-toggle__text{font-size:12px;letter-spacing:.18em}
.nav-toggle__lines{position:relative;display:block;width:18px;height:10px}
.nav-toggle__lines::before,.nav-toggle__lines::after{
  content:"";position:absolute;left:0;width:18px;height:1.5px;background:currentColor;
  transition:top .3s var(--ease),opacity .3s var(--ease);
}
.nav-toggle__lines::before{top:0}
.nav-toggle__lines::after{top:8px}
.nav-toggle[aria-expanded="true"] .nav-toggle__lines::before{top:4px}
.nav-toggle[aria-expanded="true"] .nav-toggle__lines::after{top:4px;opacity:0}

/* 滚动进度 */
.scroll-progress{
  position:fixed;top:0;left:0;right:0;height:3px;z-index:120;
  background:rgba(20,22,26,.10);pointer-events:none;
}
.scroll-progress__fill{
  display:block;width:100%;height:100%;
  transform:scaleX(0);transform-origin:left center;
  background:var(--accent-cta);
  transition:transform .12s linear;
}

/* 移动端抽屉导航 */
.rail{display:none}
.rail-nav{
  position:fixed;top:0;right:0;bottom:0;width:min(86vw,352px);z-index:90;
  display:flex;flex-direction:column;
  padding:76px 0 28px;overflow-y:auto;
  background:var(--ink);color:var(--paper);
  box-shadow:-24px 0 60px rgba(20,22,26,.28);
  transform:translateX(102%);visibility:hidden;
  transition:transform .42s var(--ease),visibility .42s step-end;
}
.rail-nav[data-open]{transform:translateX(0);visibility:visible;transition:transform .42s var(--ease),visibility 0s}
.rail-nav__list{display:flex;flex-direction:column;width:100%}
.rail-nav__item{display:flex;width:100%}
.rail-link{
  display:flex;align-items:center;justify-content:space-between;gap:16px;width:100%;
  padding:16px 26px;
  color:rgba(247,243,234,.72);
  border-bottom:1px solid rgba(247,243,234,.09);
  transition:color .3s var(--ease),background-color .3s var(--ease);
}
.rail-link__label{font-family:var(--serif);font-size:19px;letter-spacing:.14em;line-height:1.3}
.rail-link__num{font-family:var(--mono);font-size:11.5px;letter-spacing:.1em;color:rgba(247,243,234,.34)}
.rail-link:hover{color:var(--paper);background:rgba(247,243,234,.05)}
.rail-link[aria-current="page"]{color:var(--paper);background:rgba(247,243,234,.07);box-shadow:inset 3px 0 0 var(--accent-2)}
.rail-link[aria-current="page"] .rail-link__num{color:var(--accent-2)}

.rail-nav__meta{
  margin-top:auto;padding:22px 26px 0;
  display:flex;flex-direction:column;gap:12px;
  border-top:1px solid rgba(247,243,234,.12);
}
.rail-nav__meta-line{font-size:12px;letter-spacing:.14em;color:rgba(247,243,234,.5);max-width:none}
.rail-nav__meta-link{
  align-self:flex-start;padding:10px 18px;border:1px solid rgba(247,243,234,.3);border-radius:999px;
  font-size:13px;letter-spacing:.12em;color:var(--paper);
  transition:background-color .3s var(--ease),color .3s var(--ease),border-color .3s var(--ease);
}
.rail-nav__meta-link:hover{background:var(--accent-2);border-color:var(--accent-2);color:var(--ink)}

@media (max-width:1023px){
  body.is-nav-open{overflow:hidden}
  body.is-nav-open::after{
    content:"";position:fixed;inset:0;z-index:85;
    background:rgba(20,22,26,.42);
  }
}

/* 桌面端：左侧墨色轨道 */
@media (min-width:1024px){
  .topbar{display:none}
  .scroll-progress{
    top:auto;left:0;right:auto;bottom:0;
    width:var(--rail);height:3px;background:rgba(247,243,234,.14);
  }
  .rail{
    display:flex;flex-direction:column;align-items:center;
    position:fixed;top:0;left:0;bottom:0;width:var(--rail);z-index:70;
    background:var(--ink);
    border-right:1px solid rgba(247,243,234,.08);
  }
  .rail::after{
    content:"";position:absolute;left:50%;bottom:36px;width:1px;height:52px;
    transform:translateX(-50%);opacity:.55;
    background:linear-gradient(to bottom,var(--celadon),var(--ember),var(--maple),var(--frost));
  }
  .rail__brand{
    position:absolute;top:30px;left:0;right:0;
    display:flex;flex-direction:column;align-items:center;gap:14px;
    color:var(--paper);
  }
  .rail__mark{font-family:var(--serif);font-size:20px;line-height:1.1;letter-spacing:.18em;text-indent:.18em}
  .rail__sub{
    writing-mode:vertical-rl;text-orientation:upright;
    font-size:10.5px;letter-spacing:.26em;line-height:1;color:rgba(247,243,234,.42);
  }
  .rail-nav{
    top:0;left:0;right:auto;bottom:0;width:var(--rail);
    padding:186px 0 104px;overflow-y:auto;
    transform:none;visibility:visible;box-shadow:none;
    background:transparent;color:var(--paper);z-index:72;
    transition:none;
  }
  .rail-nav::-webkit-scrollbar{display:none}
  .rail-nav{scrollbar-width:none}
  .rail-nav__list{width:auto;margin:auto;align-items:center;gap:10px}
  .rail-nav__item{width:auto}
  .rail-link{
    flex-direction:row;justify-content:center;gap:8px;width:auto;
    padding:8px 7px;border-bottom:0;border-radius:5px;box-shadow:none;
    color:rgba(247,243,234,.58);
  }
  .rail-link__label{writing-mode:vertical-rl;text-orientation:upright;font-size:14px;letter-spacing:.2em;line-height:1.1}
  .rail-link__num{writing-mode:horizontal-tb;font-size:11px;color:rgba(247,243,234,.3)}
  .rail-link:hover{color:var(--paper);background:transparent}
  .rail-link[aria-current="page"]{
    color:var(--paper);background:rgba(247,243,234,.06);
    box-shadow:inset 0 0 0 1px rgba(247,243,234,.2);
  }
  .rail-link[aria-current="page"] .rail-link__num{color:var(--accent-2)}
  .rail-nav__meta{display:none}
}
@media (min-width:1024px) and (max-height:800px){
  .rail-nav{padding:150px 0 92px}
  .rail__sub{display:none}
  .rail-nav__list{gap:6px}
  .rail-link__label{font-size:13px;letter-spacing:.12em}
}
@media (min-width:1024px) and (max-height:660px){
  .rail-nav{padding:130px 0 84px}
  .rail-link{padding:5px 7px}
  .rail-link__num{display:none}
}

/* ---------- 11. 页脚 ---------- */
.site-footer{position:relative;background:var(--ink);color:rgba(247,243,234,.78)}
.footer-seasons{display:grid;grid-template-columns:repeat(4,1fr);height:5px}
.footer-seasons__band{display:block;height:100%}
.footer-seasons__band.is-spring{background:linear-gradient(90deg,var(--celadon),var(--sprout))}
.footer-seasons__band.is-summer{background:linear-gradient(90deg,var(--deep-sea),var(--ember))}
.footer-seasons__band.is-autumn{background:linear-gradient(90deg,var(--maple),var(--amber))}
.footer-seasons__band.is-winter{background:linear-gradient(90deg,var(--ink-blue),var(--frost))}

.footer__inner{
  width:min(calc(100% - var(--gutter)*2),1360px);margin-inline:auto;
  padding:64px 0 48px;
  display:grid;gap:40px;grid-template-columns:1fr;
}
@media (min-width:768px){
  .footer__inner{grid-template-columns:1.35fr 1fr 1.2fr;gap:36px;padding:80px 0 56px}
}
@media (min-width:1024px){
  .footer__inner{gap:64px;padding:96px 0 64px}
}
.footer__logo{
  font-family:var(--serif);font-weight:700;
  font-size:clamp(1.8rem,4vw,2.6rem);line-height:1.1;letter-spacing:.22em;
  color:var(--paper);
}
.footer__brandline{margin-top:10px;font-family:var(--mono);font-size:11.5px;letter-spacing:.2em;color:rgba(247,243,234,.55)}
.footer__statement{margin-top:18px;font-size:14px;line-height:1.9;color:rgba(247,243,234,.72);max-width:30em}
.footer__nav-title,.footer__contact-title{
  margin-bottom:16px;font-size:11.5px;letter-spacing:.22em;color:rgba(247,243,234,.45);
}
.footer__links{display:flex;flex-direction:column;gap:10px}
.footer__link{
  align-self:flex-start;padding-bottom:2px;
  font-size:14.5px;letter-spacing:.06em;color:rgba(247,243,234,.82);
  border-bottom:1px solid transparent;
  transition:color .3s var(--ease),border-color .3s var(--ease);
}
.footer__link:hover{color:var(--paper);border-color:var(--accent-2)}
.footer__contact-line{font-family:var(--mono);font-size:14px;letter-spacing:.03em;color:var(--paper);margin-bottom:8px;max-width:none}
.footer__address{font-size:13px;line-height:1.8;color:rgba(247,243,234,.66);max-width:24em}
.footer__service{margin-top:12px;font-size:12.5px;line-height:1.8;color:rgba(247,243,234,.5);max-width:26em}

.footer__base{
  width:min(calc(100% - var(--gutter)*2),1360px);margin-inline:auto;
  padding:22px 0 30px;border-top:1px solid rgba(247,243,234,.12);
  display:flex;flex-wrap:wrap;align-items:center;gap:14px 28px;
  font-size:12px;letter-spacing:.1em;color:rgba(247,243,234,.5);
}
.footer__copy{margin-right:auto;max-width:none}
.footer__icp{font-family:var(--mono);letter-spacing:.06em;max-width:none}
.to-top{
  padding:9px 16px;border:1px solid rgba(247,243,234,.24);border-radius:999px;
  font-size:12px;letter-spacing:.14em;color:rgba(247,243,234,.82);
  transition:background-color .3s var(--ease),color .3s var(--ease),border-color .3s var(--ease);
}
.to-top:hover{background:var(--frost);border-color:var(--frost);color:var(--ink)}

/* ---------- 12. 动效与可访问性降级 ---------- */
.js [data-reveal]{opacity:0;transform:translateY(14px)}
.js [data-reveal].is-visible{
  opacity:1;transform:none;
  transition:opacity .48s var(--ease),transform .48s var(--ease);
}
@media (prefers-reduced-motion: no-preference){
  html{scroll-behavior:smooth}
}
@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .js [data-reveal]{opacity:1;transform:none}
  .rail-nav{transition:none}
}