/* ============================================================
   老树天空 — 纸 · 墨 · 印
   ============================================================ */

:root{
  --paper:#faf9f6;
  --paper-2:#f3f1ec;
  --ink:#17181a;
  --ink-2:#3d4046;
  --muted:#787c84;
  --faint:#a8acb4;
  --line:#e4e1da;
  --line-2:#efece6;
  --seal:#b3402e;
  --seal-soft:#c9604c;

  --serif:"Kaiti SC","STKaiti","KaiTi","Noto Serif SC","Source Han Serif SC","Songti SC","SimSun",Georgia,serif;
  --sans:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",system-ui,-apple-system,sans-serif;

  --shadow-s:0 1px 2px rgba(23,24,26,.04),0 8px 24px rgba(23,24,26,.05);
  --shadow-m:0 2px 6px rgba(23,24,26,.05),0 20px 50px rgba(23,24,26,.09);
  --ease:cubic-bezier(.2,.7,.3,1);
}

*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:var(--sans);
  background:var(--paper);
  color:var(--ink);
  font-size:16px;
  line-height:1.85;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
/* 纸张纹理 */
body::before{
  content:"";position:fixed;inset:0;z-index:0;pointer-events:none;opacity:.5;
  background-image:radial-gradient(rgba(23,24,26,.028) 1px,transparent 1px);
  background-size:4px 4px;
}
a{color:inherit;text-decoration:none}
img,svg{vertical-align:middle;display:block}
::selection{background:rgba(179,64,46,.14)}
:focus-visible{outline:2px solid var(--seal);outline-offset:3px;border-radius:2px}

/* ============ 页头 ============ */
.hdr{
  position:fixed;top:0;left:0;right:0;z-index:200;
  transition:background .35s var(--ease),box-shadow .35s var(--ease),padding .35s var(--ease);
  background:transparent;
}
.hdr.scrolled{
  background:rgba(250,249,246,.86);
  backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  box-shadow:0 1px 0 var(--line-2),0 12px 34px rgba(23,24,26,.05);
}
.hdr-in{
  max-width:1080px;margin:0 auto;padding:20px 28px;
  display:flex;align-items:center;justify-content:space-between;gap:24px;
}
.hdr.scrolled .hdr-in{padding:12px 28px}

.brand{display:flex;align-items:center;gap:12px;min-width:0}
.brand-logo{
  width:40px;height:40px;flex:none;border-radius:9px;object-fit:cover;
  box-shadow:0 2px 10px rgba(23,24,26,.14);
  transition:transform .4s var(--ease);
}
.brand:hover .brand-logo{transform:rotate(-5deg) scale(1.05)}
.brand-txt{display:flex;flex-direction:column;line-height:1.25}
.brand-name{font-family:var(--serif);font-size:19px;font-weight:700;letter-spacing:.1em}
.brand-sub{font-size:11.5px;color:var(--muted);letter-spacing:.16em;margin-top:2px}

.hdr-nav{display:flex;gap:8px}
.hdr-nav a{
  font-size:14px;letter-spacing:.08em;color:var(--ink-2);
  padding:7px 15px;border-radius:999px;position:relative;
  transition:color .25s,background .25s;
}
.hdr-nav a:hover{color:var(--seal);background:rgba(179,64,46,.055)}

/* ============ 首屏 ============ */
.hero{
  position:relative;min-height:100svh;
  display:flex;flex-direction:column;justify-content:center;align-items:center;
  padding:130px 28px 90px;z-index:1;overflow:hidden;
}
.hero-art{position:absolute;inset:0;pointer-events:none;z-index:-1}
.branch{
  position:absolute;stroke:#d9d5cc;stroke-width:1.5;stroke-linecap:round;
  fill:none;opacity:.85;
}
.branch circle{fill:#d9d5cc;stroke:none}
.b-left{width:250px;left:2%;top:46%;transform:translateY(-50%) rotate(-6deg)}
.b-right{width:230px;right:3%;top:16%;transform:rotate(9deg)}

.hero-in{max-width:820px;text-align:center;position:relative}

.hero-eyebrow{
  font-size:12.5px;letter-spacing:.42em;color:var(--seal);
  text-indent:.42em;margin-bottom:30px;font-weight:500;
}
.hero-title{
  font-family:var(--serif);font-weight:700;
  font-size:clamp(34px,6.4vw,66px);
  line-height:1.36;letter-spacing:.05em;
  margin-bottom:26px;
  color:var(--ink);
}
@supports ((-webkit-background-clip:text) or (background-clip:text)){
  .hero-title{
    background:linear-gradient(175deg,#17181a 20%,#43474e 100%);
    -webkit-background-clip:text;background-clip:text;
    -webkit-text-fill-color:transparent;
  }
}
.hero-lede{
  font-family:var(--serif);font-size:clamp(16px,2.1vw,20px);
  color:var(--muted);letter-spacing:.12em;line-height:2;
  margin-bottom:44px;
}
.hero-actions{display:flex;align-items:center;justify-content:center;gap:18px;flex-wrap:wrap}
.btn-solid{
  display:inline-flex;align-items:center;
  background:var(--ink);color:#fbfaf7;
  font-size:14.5px;letter-spacing:.1em;
  padding:13px 32px;border-radius:999px;
  transition:transform .3s var(--ease),box-shadow .3s var(--ease),background .3s;
  box-shadow:0 6px 20px rgba(23,24,26,.18);
}
.btn-solid:hover{
  background:var(--seal);transform:translateY(-2px);
  box-shadow:0 12px 28px rgba(179,64,46,.28);
}
.hero-chip{
  font-size:11px;letter-spacing:.3em;color:var(--faint);
  border:1px solid var(--line);border-radius:999px;padding:8px 18px;
  text-indent:.3em;
}

.hero-scroll{
  position:absolute;bottom:38px;left:50%;transform:translateX(-50%);
  width:22px;height:36px;border:1px solid var(--line);border-radius:999px;
  display:flex;justify-content:center;padding-top:7px;
}
.hero-scroll span{
  width:3px;height:7px;border-radius:2px;background:var(--faint);
  animation:sd 1.9s var(--ease) infinite;
}
@keyframes sd{
  0%{opacity:0;transform:translateY(0)}
  35%{opacity:1}
  100%{opacity:0;transform:translateY(13px)}
}

/* ============ 作品 ============ */
.works{
  position:relative;z-index:1;
  max-width:1080px;margin:0 auto;padding:96px 28px 110px;
  border-top:1px solid var(--line-2);
}
.sec-head{
  display:flex;align-items:flex-end;justify-content:space-between;
  gap:20px;margin-bottom:46px;
}
.sec-title{
  font-family:var(--serif);font-weight:700;
  font-size:clamp(24px,3.4vw,32px);letter-spacing:.1em;
  margin-bottom:10px;position:relative;display:inline-block;padding-bottom:14px;
}
.sec-title::after{
  content:"";position:absolute;left:0;bottom:0;width:38px;height:2px;
  background:var(--seal);border-radius:2px;
}
.sec-sub{font-size:14px;color:var(--muted);letter-spacing:.08em}
.sec-count{
  font-family:var(--serif);font-size:13px;color:var(--faint);
  letter-spacing:.16em;white-space:nowrap;padding-bottom:4px;
}

.works-grid{
  display:grid;gap:22px;
  grid-template-columns:repeat(auto-fill,minmax(310px,1fr));
}

.wcard{
  position:relative;display:flex;flex-direction:column;
  background:#fff;border:1px solid var(--line);
  border-radius:14px;padding:30px 30px 34px;
  transition:transform .45s var(--ease),box-shadow .45s var(--ease),border-color .45s;
  overflow:hidden;
  opacity:1;transform:none;
}
/* 仅在 JS 可用时才启用渐入，避免脚本失效时内容不可见 */
.js .wcard{opacity:0;transform:translateY(22px)}
.js .wcard.in{opacity:1;transform:translateY(0);transition:opacity .6s var(--ease),transform .6s var(--ease),box-shadow .45s var(--ease),border-color .45s}
.wcard::before{
  content:"";position:absolute;left:0;top:0;height:100%;width:3px;
  background:var(--seal);transform:scaleY(0);transform-origin:top;
  transition:transform .45s var(--ease);
}
.wcard:hover{
  transform:translateY(-6px);
  box-shadow:var(--shadow-m);
  border-color:#dcd8cf;
}
.wcard:hover::before{transform:scaleY(1)}

.wcard-no{
  font-family:var(--serif);font-size:12px;letter-spacing:.2em;
  color:var(--faint);margin-bottom:16px;
  transition:color .35s;
}
.wcard:hover .wcard-no{color:var(--seal)}

.wcard-name{
  font-family:var(--serif);font-size:21px;font-weight:700;
  letter-spacing:.06em;margin-bottom:14px;line-height:1.4;
}
.wcard-desc{
  font-size:14px;color:var(--muted);line-height:1.85;
  letter-spacing:.02em;flex:1;
}
.wcard-go{
  position:absolute;right:26px;top:26px;
  width:32px;height:32px;border-radius:50%;
  border:1px solid var(--line);color:var(--faint);
  display:flex;align-items:center;justify-content:center;
  transition:all .4s var(--ease);
}
.wcard-go svg{width:15px;height:15px}
.wcard:hover .wcard-go{
  background:var(--seal);border-color:var(--seal);color:#fff;
  transform:rotate(45deg) scale(1.06);
}

.works-empty{
  font-size:14.5px;color:var(--muted);padding:40px 0;
}
.works-empty a{color:var(--seal);border-bottom:1px solid rgba(179,64,46,.3)}

/* ============ 页脚 ============ */
.ftr{
  position:relative;z-index:1;
  background:var(--paper-2);border-top:1px solid var(--line);
}
.ftr-in{
  max-width:1080px;margin:0 auto;padding:66px 28px 54px;
  display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:56px;
}
.ftr-name{
  font-family:var(--serif);font-size:22px;font-weight:700;letter-spacing:.12em;
  margin-bottom:7px;
}
.ftr-sub{font-size:12px;color:var(--muted);letter-spacing:.2em;margin-bottom:22px}
.ftr-text{
  font-family:var(--serif);font-size:14.5px;color:var(--ink-2);
  line-height:2;letter-spacing:.04em;max-width:330px;
}
.ftr-col h4{
  font-size:13px;font-weight:600;letter-spacing:.16em;
  color:var(--ink);margin-bottom:18px;
}
.ftr-col ul{list-style:none;display:flex;flex-direction:column;gap:11px}
.ftr-col a{
  font-size:14px;color:var(--muted);letter-spacing:.05em;
  transition:color .25s,padding-left .25s;
}
.ftr-col a:hover{color:var(--seal);padding-left:4px}
.ftr-empty{font-size:13.5px;color:var(--faint);letter-spacing:.05em}

.ftr-bottom{border-top:1px solid var(--line)}
.ftr-bottom-in{
  max-width:1080px;margin:0 auto;padding:20px 28px;
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  font-size:12.5px;color:var(--faint);letter-spacing:.08em;
}
.ftr-bottom-in a{color:var(--faint);transition:color .25s}
.ftr-bottom-in a:hover{color:var(--seal)}

/* ============ 回到顶部 ============ */
.to-top{
  position:fixed;right:26px;bottom:26px;z-index:150;
  width:42px;height:42px;border-radius:50%;
  background:#fff;border:1px solid var(--line);
  color:var(--ink-2);font-size:16px;
  display:flex;align-items:center;justify-content:center;
  cursor:pointer;opacity:0;visibility:hidden;
  transform:translateY(10px);
  transition:all .35s var(--ease);
  box-shadow:var(--shadow-s);
  font-family:var(--sans);
}
.to-top.show{opacity:1;visibility:visible;transform:translateY(0)}
.to-top:hover{background:var(--ink);color:#fff;border-color:var(--ink)}

/* ============ 响应式 ============ */
@media(max-width:900px){
  .ftr-in{grid-template-columns:1fr 1fr;gap:40px}
  .ftr-brand{grid-column:1/-1}
  .branch{opacity:.4}
  .b-left{width:170px;left:-40px}
  .b-right{width:160px;right:-30px}
}
@media(max-width:640px){
  .hdr-in{padding:14px 18px}
  .hdr.scrolled .hdr-in{padding:10px 18px}
  .brand-sub{display:none}
  .brand-name{font-size:17px}
  .hdr-nav a{padding:6px 10px;font-size:13px}
  .hero{padding:110px 20px 80px}
  .hero-eyebrow{letter-spacing:.3em;margin-bottom:24px}
  .hero-title{line-height:1.45}
  .hero-lede{margin-bottom:36px}
  .works{padding:70px 20px 80px}
  .sec-head{flex-direction:column;align-items:flex-start;gap:12px;margin-bottom:32px}
  .works-grid{grid-template-columns:1fr;gap:16px}
  .wcard{padding:24px 22px 28px}
  .wcard-go{right:20px;top:20px;width:28px;height:28px}
  .ftr-in{padding:48px 20px 40px;gap:32px}
  .ftr-bottom-in{padding:16px 20px;flex-direction:column;gap:8px}
  .branch{display:none}
  .to-top{right:16px;bottom:16px}
}
@media(prefers-reduced-motion:reduce){
  *{animation-duration:.01ms!important;transition-duration:.01ms!important}
  .wcard,.js .wcard,.js .wcard.in{opacity:1!important;transform:none!important}
}